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Sample records for aeronautical satellite communications

  1. 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).

  2. 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.

  3. 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.

  4. 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.

  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. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Packet-Based Protocol Efficiency for Aeronautical and Satellite Communications

    NASA Technical Reports Server (NTRS)

    Carek, David A.

    2005-01-01

    This paper examines the relation between bit error ratios and the effective link efficiency when transporting data with a packet-based protocol. Relations are developed to quantify the impact of a protocol s packet size and header size relative to the bit error ratio of the underlying link. These relations are examined in the context of radio transmissions that exhibit variable error conditions, such as those used in satellite, aeronautical, and other wireless networks. A comparison of two packet sizing methodologies is presented. From these relations, the true ability of a link to deliver user data, or information, is determined. Relations are developed to calculate the optimal protocol packet size forgiven link error characteristics. These relations could be useful in future research for developing an adaptive protocol layer. They can also be used for sizing protocols in the design of static links, where bit error ratios have small variability.

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

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  13. Developing a global aeronautical satellite system

    NASA Technical Reports Server (NTRS)

    Dement, Donald K.

    1988-01-01

    Arinc, an airline industry-owned and operated company in the United States, has taken steps toward establishing a global aeronautical satellite communications system. Plans call for initiation of a thin-route data operation in 1989, upgrading to establish voice communications via shared spot-beam transponders carried on other satellites, and deploying a worldwide network using dedicated satellites by 1994.

  14. Irreducible error rate in aeronautical satellite channels

    NASA Technical Reports Server (NTRS)

    Davarian, F.

    1988-01-01

    The irreducible error rate in aeronautical satellite systems is experimentally investigated. It is shown that the introduction of a delay in the multipath component of a Rician channel increases the channel irreducible error rate. However, since the carrier/multipath ratio is usually large for aeronautical applications, this rise in the irreducible error rate should not be interpreted as a practical limitation of aeronautical satellite communications.

  15. An aeronautical mobile satellite experiment

    NASA Technical Reports Server (NTRS)

    Jedrey, T. C.; Dessouky, K. I.; Lay, N. E.

    1990-01-01

    The various activities and findings of a NASA/FAA/COMSAT/INMARSAT collaborative aeronautical mobile satellite experiment are detailed. The primary objective of the experiment was to demonstrate and evaluate an advanced digital mobile satellite terminal developed at the Jet Propulsion Laboratory under the NASA Mobile Satellite Program. The experiment was a significant milestone for NASA/JPL, since it was the first test of the mobile terminal in a true mobile satellite environment. The results were also of interest to the general mobile satellite community because of the advanced nature of the technologies employed in the terminal.

  16. Experimental investigation of aeronautical and maritime communications and surveillance using satellites

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.

    1973-01-01

    The experimental program described included an evaluation of every significant factor affecting the accuracy of position fixing by range measurements from geostationary satellites. The tone-code ranging technique was found to provide a precision of roughly 0.1 n mi at mid-lattitudes with one range measurement at L-band and one at VHF. The factors which introduce bias errors were studied analytically and experimentally, and means of rectifying the bias errors were developed. An operational system at L-band may be expected to provide position fix accuracy of 0.1 n mi over large regions of the earth. The ranging technique developed within this program is digital, and uses a single signalling waveform and a single modem for communications and ranging.

  17. Inmarsat aeronautical mobile satellite system: Internetworking issues

    NASA Technical Reports Server (NTRS)

    Sengupta, Jay R.

    1990-01-01

    The Inmarsat Aeronautical Mobile Satellite System (AMSS) provides air-ground and air-air communications services to aero-mobile users on a global basis. Communicating parties may be connected either directly, or more commonly, via interconnecting networks to the Inmarsat AMSS, in order to construct end-to-end communications circuits. The aircraft earth station (AES) and the aeronautical ground earth station (GES) are the points of interconnection of the Inmarsat AMSS to users, as well as to interconnecting networks. This paper reviews the internetworking aspects of the Inmarsat AMSS, by introducing the Inmarsat AMSS network architecture and services concepts and then discussing the internetwork address/numbering and routing techniques.

  18. 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…

  19. A CCIR aeronautical mobile satellite report

    NASA Technical Reports Server (NTRS)

    Davarian, Faramaz; Bishop, Dennis; Rogers, David; Smith, Ernest K.

    1989-01-01

    Propagation effects in the aeronautical mobile-satellite service differ from those in the fixed-satellite service and other mobile-satellite services because: small antennas are used on aircraft, and the aircraft body may affect the performance of the antenna; high aircraft speeds cause large Doppler spreads; aircraft terminals must accommodate a large dynamic range in transmission and reception; and due to their high speeds, banking maneuvers, and three-dimensional operation, aircraft routinely require exceptionally high integrity of communications, making even short-term propagation effects very important. Data and models specifically required to characterize the path impairments are discussed, which include: tropospheric effects, including gaseous attenuation, cloud and rain attenuation, fog attenuation, refraction and scintillation; surface reflection (multipath) effects; ionospheric effects such as scintillation; and environmental effects (aircraft motion, sea state, land surface type). Aeronautical mobile-satellite systems may operate on a worldwide basis, including propagation paths at low elevation angles. Several measurements of multipath parameters over land and sea were conducted. In some cases, laboratory simulations are used to compare measured data and verify model parameters. The received signals is considered in terms of its possible components: a direct wave subject to atmospheric effects, and a reflected wave, which generally contains mostly a diffuse component.

  20. Aeronautical mobile satellite service: Air traffic control applications

    NASA Technical Reports Server (NTRS)

    Sim, Dave

    1990-01-01

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

  1. Multipath modeling for aeronautical communications.

    NASA Technical Reports Server (NTRS)

    Painter, J. H.; Gupta, S. C.; Wilson, L. R.

    1973-01-01

    One of the fundamental technical problems in aeronautical digital communications is that of multipath propagation between aircraft and ground terminal. This paper examines in detail a model of the received multipath signal that is useful for application of modern detection and estimation theories. The model treats arbitrary modulation and covers the selective and nonselective cases. The necessarily nonstationary statistics of the received signal are determined from the link geometry and the surface roughness parameters via a Kirchhoff solution.

  2. Aeronautical audio broadcasting via satellite

    NASA Technical Reports Server (NTRS)

    Tzeng, Forrest F.

    1993-01-01

    A system design for aeronautical audio broadcasting, with C-band uplink and L-band downlink, via Inmarsat space segments is presented. Near-transparent-quality compression of 5-kHz bandwidth audio at 20.5 kbit/s is achieved based on a hybrid technique employing linear predictive modeling and transform-domain residual quantization. Concatenated Reed-Solomon/convolutional codes with quadrature phase shift keying are selected for bandwidth and power efficiency. RF bandwidth at 25 kHz per channel, and a decoded bit error rate at 10(exp -6) with E(sub b)/N(sub o) at 3.75 dB are obtained. An interleaver, scrambler, modem synchronization, and frame format were designed, and frequency-division multiple access was selected over code-division multiple access. A link budget computation based on a worst-case scenario indicates sufficient system power margins. Transponder occupancy analysis for 72 audio channels demonstrates ample remaining capacity to accommodate emerging aeronautical services.

  3. 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

  4. Aeronautical satellite antenna steering using magnetic field sensors

    NASA Technical Reports Server (NTRS)

    Sydor, John; Dufour, Martial

    1993-01-01

    Designers of aeronautical satellite terminals are often faced with the problem of steering a directive antenna from an airplane or helicopter. This problem is usually solved by using aircraft orientation information derived from inertial sensors on-board the aircraft in combination with satellite ephemeris information calculated from geographic coordinates. This procedure works well but relies heavily on avionics that are external to the terminal. For the majority of small aircraft and helicopters which will form the bulk of future aeronautical satcom users, such avionics either do not exist or are difficult for the satellite terminal to interface with. At the Communications Research Center (CRC), work has been undertaken to develop techniques that use the geomagnetic field and satellite antenna pointing vectors (both of which are stationary in a local geographical area) to track the position of a satellite relative to a moving platform such as an aircraft. The performance of this technique is examined and a mathematical steering transformation is developed within this paper. Details are given regarding the experimental program that will be undertaken to test the concepts proposed herein.

  5. Future Aeronautical Communication Infrastructure Technology Investigation

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  6. A geostationary satellite system for mobile multimedia applications using portable, aeronautical and mobile terminals

    NASA Technical Reports Server (NTRS)

    Losquadro, G.; Luglio, M.; Vatalaro, F.

    1997-01-01

    A geostationary satellite system for mobile multimedia services via portable, aeronautical and mobile terminals was developed within the framework of the Advanced Communications Technology Service (ACTS) programs. The architecture of the system developed under the 'satellite extremely high frequency communications for multimedia mobile services (SECOMS)/ACTS broadband aeronautical terminal experiment' (ABATE) project is presented. The system will be composed of a Ka band system component, and an extremely high frequency band component. The major characteristics of the space segment, the ground control station and the portable, aeronautical and mobile user terminals are outlined.

  7. 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.

  8. Navy satellite communications

    NASA Astrophysics Data System (ADS)

    Clair, William C.

    1992-03-01

    The history, current status, and future plans of Navy satellite communications are reviewed. Particular attention is given to Fleet Satellites; the Defense Satellite Communications System; the International Maritime Satellite; Core Command and Control (Core C2), General Purpose Communications, and Navy EHF SATCOM program; and the Copernicus architecture.

  9. Aeronautical satellite data link concept, design, and flight test results

    NASA Astrophysics Data System (ADS)

    Anderson, Samuel S.; Hogle, Lawrence H.; Breitwisch, Ronald; Edwards, C. P.; Hamilton, Robert J.; Lipke, David W.

    The MITRE Corporation has conducted a three-year study of aeronautical satellite communications that culminated in a set of flight tests over the North Atlantic during August of 1985. The flight tests required the cooperation of four organizations in addition to MITRE: The Communications Satellite Corporation (COMSAT), Rockwell International, Ball Aerospace and Avantek. A test aircraft, equipped with a specially designed satellite data link terminal and antenna configuration, was flown from Cedar Rapids, Iowa across the North Atlantic to Iceland, and north of Iceland to 75° latitude. The purpose of the flight tests was to measure the performance of a full duplex aeronautical satellite data link (ASDL) using the International Maritime Satellite Organization's (INMARSAT's) spacecraft and earth station at Southbury, Connecticut, and to demonstrate potential applications. The data link operates at 200 bits-per-second (bps), uses forward error correction (FEC) coding, and employs a terminal monitor that provides interfaces to on-board avionics, data recording equipment, and an industry-standard personal computer (PC). The PC serves as a user terminal as well as a real-time monitor of bit-error-rate (BER) performance. In addition to channel propagation and BER experiments, demonstrations of potential applications of an oceanic ASDL system were conducted. A standard commercial airline data link management unit (MU) was used to communicate data over the ASDL using standard protocols. The interface to the MU allowed access to data from two distinct navigation systems: an inertial navigation system (INS) and a Global Positioning System (GPS) receiver. Aircraft position data was transmitted from the aircraft to the earth station on an automatic basis to simulate automatic dependent surveillance (ADS) of oceanic air space. This paper is divided into three sections: 1) A discussion of background issues, such as the motivation for the reported research and development, and

  10. Technology Assessment for the Future Aeronautical Communications System

    NASA Technical Reports Server (NTRS)

    Budinger, James M. (Technical Monitor)

    2005-01-01

    To address emerging saturation in the VHF aeronautical bands allocated internationally for air traffic management communications, the International Civil Aviation Organization (ICAO) has requested development of a common global solution through its Aeronautical Communications Panel (ACP). In response, the Federal Aviation Administration (FAA) and Eurocontrol initiated a joint study, with the support of NASA and U.S. and European contractors, to provide major findings on alternatives and recommendations to the ICAO ACP Working Group C (WG-C). Under an FAA/Eurocontrol cooperative research and development agreement, ACP WG-C Action Plan 17 (AP-17), commonly referred to as the Future Communications Study (FCS), NASA Glenn Research Center is responsible for the investigation of potential communications technologies that support the long-term mobile communication operational concepts of the FCS. This report documents the results of the first phase of the technology assessment and recommendations referred to in the Technology Pre-Screening Task 3.1 of AP-17. The prescreening identifies potential technologies that are under development in the industry and provides an initial assessment against a harmonized set of evaluation criteria that address high level capabilities, projected maturity for the time frame for usage in aviation, and potential applicability to aviation. A wide variety of candidate technologies were evaluated from several communications service categories including: cellular telephony; IEEE-802.xx standards; public safety radio; satellite and over-the-horizon communications; custom narrowband VHF; custom wideband; and military communications.

  11. Interference Analysis for an Aeronautical Mobile Airport Communications System

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.; Kercewski, Robert J.

    2010-01-01

    The next generation of aeronautical communications for airport surface applications has been identified through a NASA research program and an international collaborative future communications study. The result, endorsed by both the United States and European regulatory agencies is called AeroMACS (Aeronautical Mobile Airport Communications System) and is based upon the IEEE 802.16e mobile wireless standard. Coordinated efforts to develop appropriate aviation standards for the AeroMACS system are now underway within RTCA (United States) and Eurocae (Europe). AeroMACS will be implemented in a recently allocated frequency band, 5091- 5150 MHz. As this band is also occupied by fixed satellite service uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference to the fixed satellite service are under analysis in order to enable the definition of standards that assure that such interference will be avoided. The NASA Glenn Research Center has been involved in this analysis, and the first results of modeling and simulation efforts directed at this analysis are the subject of this paper.12

  12. Interference Analysis for an Aeronautical Mobile Airport Communications System

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.; Kerczewski, Robert J.

    2011-01-01

    The next generation of aeronautical communications for airport surface applications has been identified through a NASA research program and an international collaborative future communications study. The result, endorsed by both the United States and European regulatory agencies is called AeroMACS (Aeronautical Mobile Airport Communications System) and is based upon the IEEE 802.16e mobile wireless standard. Coordinated efforts to develop appropriate aviation standards for the AeroMACS system are now underway within RTCA (United States) and Eurocae (Europe). AeroMACS will be implemented in a recently allocated frequency band, 5091-5150 MHz. As this band is also occupied by fixed satellite service uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference to the fixed satellite service are under analysis in order to enable the definition of standards that assure that such interference will be avoided. The NASA Glenn Research Center has been involved in this analysis, and the first results of modeling and simulation efforts directed at this analysis are the subject of this presentation.

  13. Aeronautical Satellite-Assisted Process for Information Exchange Through Network Technologies (Aero-SAPIENT) Conducted

    NASA Technical Reports Server (NTRS)

    Zernic, Michael J.

    2002-01-01

    Broadband satellite communications for aeronautics marries communication and network technologies to address NASA's goals in information technology base research and development, thereby serving the safety and capacity needs of the National Airspace System. This marriage of technology increases the interactivity between airborne vehicles and ground systems. It improves decision-making and efficiency, reduces operation costs, and improves the safety and capacity of the National Airspace System. To this end, a collaborative project called the Aeronautical Satellite Assisted Process for Information Exchange through Network Technologies, or Aero-SAPIENT, was conducted out of Tinker AFB, Oklahoma, during November and December 2000.

  14. 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.

  15. Tethered Communication Satellites

    NASA Technical Reports Server (NTRS)

    Von Tiesenhausen, G.

    1986-01-01

    Report describes concept for placing several communication satellites in geostationary orbit without taking up more space than assigned to single satellite. Proposed scheme eases orbital crowding more economically than space platforms. Concept requires minimal redesign of existing satellites and accommodates many satellites in just one orbital slot. System much lighter in weight than geostationary platform and easier and more economical to transport.

  16. 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.

  17. 77 FR 30046 - Ninth Meeting: RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite (Route) Services

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ... Satellite (Route) Services AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite... RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite (Route) Services. DATES: The...

  18. 76 FR 66350 - Eighth Meeting: RTCA Special Committee 222 Inmarsat Aeronautical Mobile Satellite (Route) Services

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-26

    ... Satellite (Route) Services AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Notice of RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite (Route... Committee 222, Inmarsat Aeronautical Mobile Satellite (Route) Services for the Eighth Meeting. DATES:...

  19. 77 FR 48584 - Tenth Meeting: RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite (Route) Services

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-14

    ... Satellite (Route) Services AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite... RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite (Route) Services. DATES: The...

  20. Trends In Satellite Communication

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  1. Identification of Technologies for Provision of Future Aeronautical Communications

    NASA Technical Reports Server (NTRS)

    Gilbert, Tricia; Dyer, Glen; Henriksen, Steve; Berger, Jason; Jin, Jenny; Boci, Tony

    2006-01-01

    This report describes the process, findings, and recommendations of the second of three phases of the Future Communications Study (FCS) technology investigation conducted by NASA Glenn Research Center and ITT Advanced Engineering & Sciences Division for the Federal Aviation Administration (FAA). The FCS is a collaborative research effort between the FAA and Eurocontrol to address frequency congestion and spectrum depletion for safety critical airground communications. The goal of the technology investigation is to identify technologies that can support the longterm aeronautical mobile communication operating concept. A derived set of evaluation criteria traceable to the operating concept document is presented. An adaptation of the analytical hierarchy process is described and recommended for selecting candidates for detailed evaluation. Evaluations of a subset of technologies brought forward from the prescreening process are provided. Five of those are identified as candidates with the highest potential for continental airspace solutions in L-band (P-34, W-CDMA, LDL, B-VHF, and E-TDMA). Additional technologies are identified as best performers in the unique environments of remote/oceanic airspace in the satellite bands (Inmarsat SBB and a custom satellite solution) and the airport flight domain in C-band (802.16e). Details of the evaluation criteria, channel models, and the technology evaluations are provided in appendixes.

  2. 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.

  3. Robust Timing Synchronization in Aeronautical Mobile Communication Systems

    NASA Technical Reports Server (NTRS)

    Xiong, Fu-Qin; Pinchak, Stanley

    2004-01-01

    This work details a study of robust synchronization schemes suitable for satellite to mobile aeronautical applications. A new scheme, the Modified Sliding Window Synchronizer (MSWS), is devised and compared with existing schemes, including the traditional Early-Late Gate Synchronizer (ELGS), the Gardner Zero-Crossing Detector (GZCD), and the Sliding Window Synchronizer (SWS). Performance of the synchronization schemes is evaluated by a set of metrics that indicate performance in digital communications systems. The metrics are convergence time, mean square phase error (or root mean-square phase error), lowest SNR for locking, initial frequency offset performance, midstream frequency offset performance, and system complexity. The performance of the synchronizers is evaluated by means of Matlab simulation models. A simulation platform is devised to model the satellite to mobile aeronautical channel, consisting of a Quadrature Phase Shift Keying modulator, an additive white Gaussian noise channel, and a demodulator front end. Simulation results show that the MSWS provides the most robust performance at the cost of system complexity. The GZCD provides a good tradeoff between robustness and system complexity for communication systems that require high symbol rates or low overall system costs. The ELGS has a high system complexity despite its average performance. Overall, the SWS, originally designed for multi-carrier systems, performs very poorly in single-carrier communications systems. Table 5.1 in Section 5 provides a ranking of each of the synchronization schemes in terms of the metrics set forth in Section 4.1. Details of comparison are given in Section 5. Based on the results presented in Table 5, it is safe to say that the most robust synchronization scheme examined in this work is the high-sample-rate Modified Sliding Window Synchronizer. A close second is its low-sample-rate cousin. The tradeoff between complexity and lowest mean-square phase error determines

  4. 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…

  5. 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…

  6. 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)

  7. 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.

  8. 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)

  9. 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.

  10. The European Communications Satellite

    NASA Astrophysics Data System (ADS)

    Stone, T. A.

    1985-09-01

    Two European Communication Satellites (ECSs) are now in operation for Eutelsat, forming the orbital portion of a communications system that will operate until 1993, carrying telephony and TV for the European Broadcasting Union. A total of five ECSs are to be constructed in order to ensure continuity of service over the systems lifetime. ECSs will also serve as the bases for the European Regional Communication System, which furnishes small receiver dish specialized services and preemptive TV distribution channels within Europe.

  11. 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.

  12. Aeronautical Satellite Data Link System (SDLS) for high-density air-traffic areas

    NASA Technical Reports Server (NTRS)

    Delrieu, Alain; Loisy, Claude; Clinch, Philip; Benhaim, Philippe

    1995-01-01

    The European Space Agency has recently commissioned a study to investigate the feasibility of a low-cost aeronautical Satellite Data Link System (SDLS) to provide for the needs of Air Traffic Services, i.e. safety related communications over continental areas with high air-traffic density. This study is placed in today's context which sees the first generation of Aeronautical Mobile Satellite System (AMSS) being gradually but restrictively put into service in oceanic airspaces with low air-traffic density. This paper first discusses the case of ATS dedicated versus mixed (ATS and commercial) Comms service provision and identifies the specific ATS comms requirements context. Specific emphasis is put on the ICAO (International Civil Aviation Organization) standardization framework for both the ATN (Aeronautical Telecommunication Network) and the SSR (Secondary Surveillance Radar) Mode S specific services. An architectural system and network design for a future SDLS is then proposed, such as to meet the ATS comms requirements within the realm of existing technologies. To minimize development risk and cost, consideration is given to re-use the ESA-developed Land Mobile Communication Technology, known as MSBN (Mobile Satellite Business Network) featuring distinct subnetworks. It is particularly suited to an ATM (Air Traffic Management) decentralized architecture made of independent ATC (Air Traffic Control) Centers. Finally the study follow-on phase is introduced, which is intended to cover system design and development leading to a demonstration program, as a first step towards proposals for international standardization and acceptance.

  13. 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.

  14. 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.

  15. 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.

  16. 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)

  17. 75 FR 15770 - Fifth Meeting-Special Committee 222: Inmarsat Aeronautical Mobile Satellite (Route) Services

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-30

    ... Satellite (Route) Services AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 222: Inmarsat Aeronautical Mobile Satellite (Route) Services meeting. SUMMARY: The FAA... Aeronautical Mobile Satellite (Route) Services. DATES: The meeting will be held Tuesday, April 20, 2010 from...

  18. 75 FR 63534 - Seventh Meeting-Special Committee 222: Inmarsat Aeronautical Mobile Satellite (Route) Services

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-15

    ... Satellite (Route) Services AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 222: Inmarsat Aeronautical Mobile Satellite (Route) Services meeting. SUMMARY: The FAA... Aeronautical Mobile Satellite (Route) Services. DATES: The meeting will be held November 3-5, 2010,...

  19. 75 FR 39724 - Sixth Meeting-Special Committee 222: Inmarsat Aeronautical Mobile Satellite (Route) Services

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-12

    ... Satellite (Route) Services AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 222: Inmarsat Aeronautical Mobile Satellite (Route) Services meeting. SUMMARY: The FAA... Aeronautical Mobile Satellite (Route) Services. DATES: The meeting will be held Tuesday, August 3, 2010 from...

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. Aeronautical-Satellite-Assisted Process Being Developed for Information Exchange Through Network Technologies (Aero-SAPIENT)

    NASA Technical Reports Server (NTRS)

    Zernic, Michael J.

    2001-01-01

    Communications technologies are being developed to address safety issues during aviation travel. Some of these technologies enable the aircraft to be in constant bidirectional communications with necessary systems, people, and other aircraft that are not currently in place today. Networking technologies, wireless datalinks, and advanced avionics techniques are areas of particular importance that the NASA Glenn Research Center has contributed. Glenn, in conjunction with the NASA Ames Research Center, NASA Dryden Flight Research Center, and NASA Langley Research Center, is investigating methods and applications that would utilize these communications technologies. In mid-June 2000, the flight readiness of the network and communications technologies were demonstrated via a simulated aircraft. A van simulating an aircraft was equipped with advanced phased-array antennas (Advanced Communications/Air Traffic Management (AC/ATM) Advanced Air Transportation Technologies (AATT) project) that used commercial Ku-band satellite communications to connect Glenn, Dryden, and Ames in a combined system ground test. This test simulated air-ground bidirectional transport of real-time digital audio, text, and video data via a hybrid network configuration that demonstrated the flight readiness of the network and communications technologies. Specifically, a Controller Pilot Data Link Communications application was used with other applications to demonstrate a multiprotocol capability via Internet-protocol encapsulated ATN (Aeronautical Telecommunications Network) data packets. The significance of this combined ground test is its contribution to the Aero Information Technology Base Program Level I milestone (Software Technology investment area) of a real-time data link for the National Airspace System. The objective of this milestone was to address multiprotocol technology applicable for real-time data links between aircraft, a satellite, and the ground as well as the ability to

  5. 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.

  6. Emerging Definition of Next-Generation of Aeronautical Communications

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.

    2006-01-01

    Aviation continues to experience rapid growth. In regions such as the United States and Europe air traffic congestion is constraining operations, leading to major new efforts to develop methodologies and infrastructures to enable continued aviation growth through transformational air traffic management systems. Such a transformation requires better communications linking airborne and ground-based elements. Technologies for next-generation communications, the required capacities, frequency spectrum of operation, network interconnectivity, and global interoperability are now receiving increased attention. A number of major planning and development efforts have taken place or are in process now to define the transformed airspace of the future. These activities include government and industry led efforts in the United States and Europe, and by international organizations. This paper will review the features, approaches, and activities of several representative planning and development efforts, and identify the emerging global consensus on requirements of next generation aeronautical communications systems for air traffic control.

  7. Aeronautical Mobile Airport Communications System (AeroMACS)

    NASA Technical Reports Server (NTRS)

    Budinger, James M.; Hall, Edward

    2011-01-01

    To help increase the capacity and efficiency of the nation s airports, a secure wideband wireless communications system is proposed for use on the airport surface. This paper provides an overview of the research and development process for the Aeronautical Mobile Airport Communications System (AeroMACS). AeroMACS is based on a specific commercial profile of the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard known as Wireless Worldwide Interoperability for Microwave Access or WiMAX (WiMax Forum). The paper includes background on the need for global interoperability in air/ground data communications, describes potential AeroMACS applications, addresses allocated frequency spectrum constraints, summarizes the international standardization process, and provides findings and recommendations from the world s first AeroMACS prototype implemented in Cleveland, Ohio, USA.

  8. Additional Technologies and Investigations for Provision of Future Aeronautical Communications

    NASA Technical Reports Server (NTRS)

    Gilbert, Tricia; Jin, Jenny; Berger, Jason; Henriksen, Steve

    2008-01-01

    The following NASA Contractor Report documents the in-depth studies on select technologies that could support long-term aeronautical mobile communications operating concepts. This work was performed during the third and final phase of NASA s Technology Assessment for the Federal Aviation Administration (FAA)/EUROCONTROL Future Communications Study (FCS) under a multiyear NASA contract. It includes the associated findings of ITT Corporation and NASA Glenn Research Center to the FAA as of the end of May 2007. The activities documented in this report focus on three final technology candidates identified by the United States, and were completed before sufficient information about two additional technology candidates proposed by EUROCONTROL was made available. A separate report to be published by NASA/CR-2008-215144, entitled Final Report on Technology Investigations for Provision of Future Aeronautical Communications will include an assessment of all five final candidate technologies considered by the U.S. agencies (FAA and NASA) and EUROCONTROL. It will also provide an overview of the entire technology assessment process, including final recommendations. All three phases of this work were performed in compliance with the Terms of Reference for the Action Plan number 17 (AP-17) cooperative research agreement among EUROCONTROL, FAA, and NASA along with the general guidance of the FAA and EUROCONTROL available throughout this study.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. A TDMA Broadcast Satellite/Ground Architecture for the Aeronautical Telecommunications Network

    NASA Technical Reports Server (NTRS)

    Shamma, Mohammed A.; Raghavan, Rajesh S.

    2003-01-01

    An initial evaluation of a TDMA satellite broadcast architecture with an integrated ground network is proposed in this study as one option for the Aeronautical Telecommunications Network (ATN). The architecture proposed consists of a ground based network that is dedicated to the reception and transmissions of Automatic Dependent Surveillance Broadcast (ADS-B) messages from Mode-S or UAT type systems, along with tracks from primary and secondary surveillance radars. Additionally, the ground network could contain VHF Digital Link Mode 2, 3 or 4 transceivers for the reception and transmissions of Controller-Pilot Data Link Communications (CPDLC) messages and for voice. The second part of the ATN network consists of a broadcast satellite based system that is mainly dedicated for the transmission of surveillance data as well as En-route Flight Information Service Broadcast (FIS-B) to all aircraft. The system proposed integrates those two network to provide a nation wide comprehensive service utilizing near term or existing technologies and hence keeping the economic factor in prospective. The next few sections include a background introduction, the ground subnetwork, the satellite subnetwork, modeling and simulations, and conclusion and recommendations.

  15. 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.

  16. 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.

  17. 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.

  18. Mobile satellite communications for consumers

    NASA Astrophysics Data System (ADS)

    Noreen, Gary K.

    1991-11-01

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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Computer simulation and performance assessment of the packet-data service of the Aeronautical Mobile Satellite Service (AMSS)

    NASA Technical Reports Server (NTRS)

    Ferzali, Wassim; Zacharakis, Vassilis; Upadhyay, Triveni; Weed, Dennis; Burke, Gregory

    1995-01-01

    The ICAO Aeronautical Mobile Communications Panel (AMCP) completed the drafting of the Aeronautical Mobile Satellite Service (AMSS) Standards and Recommended Practices (SARP's) and the associated Guidance Material and submitted these documents to ICAO Air Navigation Commission (ANC) for ratification in May 1994. This effort, encompassed an extensive, multi-national SARP's validation. As part of this activity, the US Federal Aviation Administration (FAA) sponsored an effort to validate the SARP's via computer simulation. This paper provides a description of this effort. Specifically, it describes: (1) the approach selected for the creation of a high-fidelity AMSS computer model; (2) the test traffic generation scenarios; and (3) the resultant AMSS performance assessment. More recently, the AMSS computer model was also used to provide AMSS performance statistics in support of the RTCA standardization activities. This paper describes this effort as well.

  4. Commercialization of Advanced Communications Technology Satellite (ACTS) technology

    NASA Astrophysics Data System (ADS)

    Plecity, Mark S.; Strickler, Walter M.; Bauer, Robert A.

    1996-03-01

    In an on-going effort to maintain United States leadership in communication satellite technology, the National Aeronautics and Space Administration (NASA), led the development of the Advanced Communications Technology Satellite (ACTS). NASA's ACTS program provides industry, academia, and government agencies the opportunity to perform both technology and telecommunication service experiments with a leading-edge communication satellite system. Over 80 organizations are using ACTS as a multi server test bed to establish communication technologies and services of the future. ACTS was designed to provide demand assigned multiple access (DAMA) digital communications with a minimum switchable circuit bandwidth of 64 Kbps, and a maximum channel bandwidth of 900 MHZ. It can, therefore, provide service to thin routes as well as connect fiber backbones in supercomputer networks, across oceans, or restore full communications in the event of national or manmade disaster. Service can also be provided to terrestrial and airborne mobile users. Commercial applications of ACTS technologies include: telemedicine; distance education; Department of Defense operations; mobile communications, aeronautical applications, terrestrial applications, and disaster recovery. This paper briefly describes the ACTS system and the enabling technologies employed by ACTS including Ka-band hopping spot beams, on-board routing and switching, and rain fade compensation. When used in conjunction with a time division multiple access (TDMA) architecture, these technologies provide a higher capacity, lower cost satellite system. Furthermore, examples of completed user experiments, future experiments, and plans of organizations to commercialize ACTS technology in their own future offerings will be discussed.

  5. Research Supporting Satellite Communications Technology

    NASA Technical Reports Server (NTRS)

    Horan Stephen; Lyman, Raphael

    2005-01-01

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

  6. Interference Analysis Status and Plans for Aeronautical Mobile Airport Communications System (AeroMACS)

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Wilson, Jeffrey D.

    2010-01-01

    Interference issues related to the operation of an aeronautical mobile airport communications system (AeroMACS) in the C-Band (specifically 5091-5150 MHz) is being investigated. The issue of primary interest is co-channel interference from AeroMACS into mobile-satellite system (MSS) feeder uplinks. The effort is focusing on establishing practical limits on AeroMACS transmissions from airports so that the threshold of interference into MSS is not exceeded. The analyses are being performed with the software package Visualyse Professional, developed by Transfinite Systems Limited. Results with omni-directional antennas and plans to extend the models to represent AeroMACS more accurately will be presented. These models should enable realistic analyses of emerging AeroMACS designs to be developed from NASA Test Bed, RTCA 223, and European results.

  7. Launch vehicles for communications satellites

    NASA Technical Reports Server (NTRS)

    Mahon, J. B.

    1982-01-01

    After giving brief development histories of the Delta and the Atlas Centaur launch vehicles, attention is given to the operational characteristics of the ascent, parking orbit, transfer orbit, and orbital insertion phases of the delivery of a communications satellite to a geostationary orbit by means of a Delta launch vehicle. NASA plans to employ Delta vehicles for as long as they are needed during the transition period to the Space Shuttle. NASA planning for Atlas Centaur includes launches through 1985 for INTELSAT-VA, and through 1986 for FLTSATCOM satellites.

  8. 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.

  9. 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.

  10. ACTS broadband aeronautical experiment

    NASA Technical Reports Server (NTRS)

    Abbe, Brian S.; Jedrey, Thomas C.; Estabrook, Polly; Agan, Martin J.

    1993-01-01

    In the last decade, the demand for reliable data, voice, and video satellite communication links between aircraft and ground to improve air traffic control, airline management, and to meet the growing demand for passenger communications has increased significantly. It is expected that in the near future, the spectrum required for aeronautical communication services will grow significantly beyond that currently available at L-band. In anticipation of this, JPL is developing an experimental broadband aeronautical satellite communications system that will utilize NASA's Advanced Communications Technology Satellite (ACTS) as a satellite of opportunity and the technology developed under JPL's ACTS Mobile Terminal (AMT) Task to evaluate the feasibility of using K/Ka-band for these applications. The application of K/Ka-band for aeronautical satellite communications at cruise altitudes is particularly promising for several reasons: (1) the minimal amount of signal attenuation due to rain; (2) the reduced drag due to the smaller K/Ka-band antennas (as compared to the current L-band systems); and (3) the large amount of available bandwidth. The increased bandwidth available at these frequencies is expected to lead to significantly improved passenger communications - including full-duplex compressed video and multiple channel voice. A description of the proposed broadband experimental system will be presented including: (1) applications of K/Ka-band aeronautical satellite technology to U.S. industry; (2) the experiment objectives; (3) the experiment set-up; (4) experimental equipment description; and (5) industrial participation in the experiment and the benefits.

  11. 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.

  12. 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.

  13. 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.

  14. Cockpit weather graphics using mobile satellite communications

    NASA Astrophysics Data System (ADS)

    Seth, Shashi

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

  15. 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.

  16. Multipurpose Communication Satellite solar array

    NASA Astrophysics Data System (ADS)

    Bastard, J. L.; Guyot, Ph.

    Through research and development studies, Aerospatiale has developed with the French National Space Agency (CNES) a new concept of a rigid Solar Array (GSR) which covers a range of power between 1 kW and 10 kW EOL 7 yr. This technology is used by Aerospatiale on the currently running programs:—TELECOM 1, Telecommunication satellite, spinned in transfer; —ARABSAT, Telecommunication satellite, 3-axis stabilized in transfer; —TELE-X and TV-SAT/TDF1, Direct Broadcasting satellites, 3-axis stabilized in transfer. This paper deals with the description and the electrical and mechanical performance of the Multipurpose Communication Satellite Solar Array (M.C.S.). For this satellite, which is expected to be launched in 1984, Aerospatiale has selected the following concept: primary power (1.4 kW EOL 7 yr) will be provided by two separate sun-oriented solar array wings equipped with AEG Telefunken BSR (Back Surface Reflector) solar cells. This solar generator is directly derived from the GSR technology. Owing to the three-axis stabilization of the satellite and the partial deployment of the solar array during the transfer phase it has been necessary to use a primary and a secondary hold-down devices. In the same way the position of the shunt on the solar generator induced an increase of the mass, because of the supplementary hold-down point and of the support structure. Now scribing Laser System leads to the optimization of the solar cells dimensions and allows a better fill factor of the panels and so an increase of the power performance. Beside the M.C.S concept which is fully adapted as regards its mission specifications, it was interesting to present different concepts of solar generators optimized not only as regards mass budget but also power budget. These concepts covering a large range of powers are fully adapted to telecommunication missions.

  17. 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.

  18. Antennas for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Huang, John

    1991-01-01

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

  19. 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.

  20. 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.

  1. ACTS broadband aeronautical terminal

    NASA Technical Reports Server (NTRS)

    Agan, M. J.; Densmore, A. C.

    1995-01-01

    This paper discusses the design of, and experiments with, the ACTS Broadband Aeronautical Terminal. As part of the ongoing effort to investigate commercial applications of ACTS technologies, NASA's Jet Propulsion Laboratory and various industry/government partners are developing a broadband mobile terminal for aeronautical applications. The ACTS Broadband Aeronautical Terminal is designed to explore the use of K/Ka-band for high data rate aeronautical satellite communications. Currently available commercial aeronautical satellite communications systems are only capable of achieving data rates on the order of tens of kilobits per second. The broadband terminal used in conjunction with the ACTS mechanically steerable antenna, can achieve data rates of 384 kilobits per second, while use of an ACTS spot beam antenna with this terminal will allow up to T1 data rates (1.544 megabits per second). The aeronautical terminal will be utilized to test a variety of applications that require a high data rate communications link. The use of the K/Ka-band for wideband aeronautical communications has the advantages of spectrum availability and smaller antennas, while eliminating the one major drawback of this frequency band, rain attenuation, by flying above the clouds the majority of the time.

  2. Cost Consideration for Future Communications Satellite

    NASA Astrophysics Data System (ADS)

    Iida, Takashi

    2002-01-01

    This paper discusses the cost driving factors of the future communications satellite rather than discussing its cost itself directly, in terms of development period of time, services, and R&D by government. In the first, a period of time for development of a communications system is discussed in comparison of satellite communications system with a terrestrial communications system. Generally speaking, the terrestrial communications system is developed in a short period. Especially, the recent network related IT technology changes very rapidly, like so-called as "Dog Year". On the other hand, it takes a long time, more than several years, to develop a satellite communications system. This paper will discuss this time period of development is how to influence the system realization in various cases. In the second, the service related cost is discussed. First, a mobile communications satellite system is considered as an example. The tremendous penetration speed of the terrestrial cellular phones prevents from the success of the mobile satellite communications system. The success of the mobile satellite communications system depends on how early and user friendly to develop its user terminals. Second, the broadcasting service is described as a successful example. It is described that the satellite broadcasting has a very competitive advantage to the terrestrial broadcasting service from the cost point of view. Finally, the cost of the technology R&D for the future communication satellite by the government is discussed. A model of the future communications satellite for next 30 years has been proposed(1)(2). As an example, this paper estimates the satellite cost of the 60 Gbps range of capacity which is called as 1.5G satellite, where the capacity of the second generation Internet satellite (2G) is 50-500 Gbps per satellite. In the paper, the R&D plan of the future communications satellite will be discussed as a next R&D project to the first generation Internet

  3. National Aeronautics and Space Administration plans for space communication technology

    NASA Technical Reports Server (NTRS)

    Alexovich, R. E.

    1979-01-01

    A program plan is presented for a space communications application utilizing the 30/20 GHz frequency bands (30 GHz uplink and 20 GHz downlink). Results of market demand studies and spacecraft systems studies which significantly affect the supporting research and technology program are also presented, along with the scheduled activities of the program plan.

  4. Twenty years of international satellite communication

    NASA Astrophysics Data System (ADS)

    Evans, J. V.

    1986-08-01

    The development of satellite communications networks since 1957 is reviewed, and future trends are discussed. The emphasis is on commercial networks such as Comsat and Intelsat, and consideration is given to the early experimental satellites; the advantages of GEO satellites; the steady growth of the capabilities of satellite systems; advances in orbital injection and stationkeeping, stability and attitude control, and payload design; and communication-capacity improvements (increased bandwidths, shaped beams, TDMA, satellite-switched TDMA, and circuit multiplication). It is predicted that competition from undersea fiber-optic cables in the telephony market will shift the emphasis in satellite communications toward DBS-TV (especially in Europe), thin-route telephone and data communication using smaller earth stations, and mobile-station communication. Graphs, maps, photographs, and diagrams are provided.

  5. Technical Communications in Aeronautics: Results of an Exploratory Study. NASA Technical Memorandum 101534, Parts 1 and 2.

    ERIC Educational Resources Information Center

    Pinelli, Thomas E.; And Others

    An exploratory study investigated technical communications in aeronautics by surveying aeronautical engineers and scientists. The study had five specific objectives: to solicit the opinions of aeronautical engineers and scientists regarding the importance of technical communications to their profession; to determine their use and production of…

  6. 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…

  7. 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…

  8. 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.

  9. 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…

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Satellite Communication Hardware Emulation System (SCHES)

    NASA Technical Reports Server (NTRS)

    Kaplan, Ted

    1993-01-01

    Satellite Communication Hardware Emulator System (SCHES) is a powerful simulator that emulates the hardware used in TDRSS links. SCHES is a true bit-by-bit simulator that models communications hardware accurately enough to be used as a verification mechanism for actual hardware tests on user spacecraft. As a credit to its modular design, SCHES is easily configurable to model any user satellite communication link, though some development may be required to tailor existing software to user specific hardware.

  15. 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

  16. Advanced high capacity domestic satellite communications system

    NASA Astrophysics Data System (ADS)

    Iso, Akio; Kohiyama, Kenji; Odate, Hitoshi; Ishida, Noriaki

    This paper describes a concept of multibeam high capacity transmission possible with a 30/20 GHz and 50/40 GHz domestic satellite communication system. The relationship between satellite antenna pointing accuracy and multi-beam antenna interference, as well as the relationship between satellite antenna pointing accuracy and multi-satellite interference are looked at. The ultra high capacity domestic satellite communication system will have multi-beam antennas with a 76.0 dB at both 20 GHz and 40 GHz. These antennas will provide 4950 beams that approximately correspond to the number of end office of the Japanese telephone network, and have a pointing accuracy of 0.005 degrees. This system will be equipped with 9900 30/20 GHz and 50/40 GHz transponder channels with bit rates of 800 Mbps. Its capacity will be 119 Tbps through use of 15 large communication satellite platforms.

  17. 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.

  18. 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.

  19. A potential 21st century satellite communications application - Personal communications

    NASA Astrophysics Data System (ADS)

    Tsang, E. K.; Douville, R.

    1990-03-01

    It has been forecast that not only will the future needs for satellite communications grow, especially in the area of broadcasting and mobile services, but also that the requirements will be diversified. For voice and data traffic, satellite communications started with the requirements of the telephone companies. Over the past few years, with the availability of Ku-band and VSAT systems, private business networks have emerged. Heading into the 21st century, satellite communications will expand into the personal services domain. This paper describes a concept for a satellite-based personal radio system. To realize the personal communications system, the portable terminals have to be inexpensive and small, similar to the present portable or handheld cellular radio-phones in size. The system aspects, such as selection of frequency band, multiple access and payload configuration will be addressed. The advanced technology required for the portable personal satellite communications system will be discussed.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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…

  6. 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…

  7. 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.

  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. 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.

  10. Communication satellites: Guidelines for a strategic plan

    NASA Technical Reports Server (NTRS)

    1987-01-01

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

  11. Polarization tracking for quantum satellite communications

    NASA Astrophysics Data System (ADS)

    Wang, Gang; Shen, Dan; Chen, Genshe; Pham, Khanh; Blasch, Erik

    2014-06-01

    Satellite networks and quantum communications offer complementary opportunities for enhanced operations. Quantum communications provide security for the transmissions between satellites and ground stations; while the free-space link of satellite networks provide the potential of long distance transmission of quantum bits (qubit) for space communications. However, with the promising advantages of the two approaches, challenges remain to fully develop quantum-based satellite communications such as robust and reliable information detection which is difficult to achieve due to the movement of satellites. In this paper, a tracking algorithm is proposed for polarization-encoded quantum satellite communications where polarization states are used to determine the bit transfer between the transmitter and receiver. The polarization tracking is essential for the decoding of a qubit and the quantum key distribution (QKD). A practical channel model for free-space quantum communications is adopted in this paper. With the estimated polarization, a novel dynamic polarization compensation scheme is also proposed. The results show that our methods can accurately estimate the polarization, providing much lower quantum bit error rate (QBER) by compensation, as compared with the direct qubit detection without polarization tracking and compensation scheme.

  12. Automation of orbit determination functions for National Aeronautics and Space Administration (NASA)-supported satellite missions

    NASA Technical Reports Server (NTRS)

    Mardirossian, H.; Beri, A. C.; Doll, C. E.

    1990-01-01

    The Flight Dynamics Facility (FDF) at Goddard Space Flight Center (GSFC) provides spacecraft trajectory determination for a wide variety of National Aeronautics and Space Administration (NASA)-supported satellite missions, using the Tracking Data Relay Satellite System (TDRSS) and Ground Spaceflight and Tracking Data Network (GSTDN). To take advantage of computerized decision making processes that can be used in spacecraft navigation, the Orbit Determination Automation System (ODAS) was designed, developed, and implemented as a prototype system to automate orbit determination (OD) and orbit quality assurance (QA) functions performed by orbit operations. Based on a machine-resident generic schedule and predetermined mission-dependent QA criteria, ODAS autonomously activates an interface with the existing trajectory determination system using a batch least-squares differential correction algorithm to perform the basic OD functions. The computational parameters determined during the OD are processed to make computerized decisions regarding QA, and a controlled recovery process is activated when the criteria are not satisfied. The complete cycle is autonomous and continuous. ODAS was extensively tested for performance under conditions resembling actual operational conditions and found to be effective and reliable for extended autonomous OD. Details of the system structure and function are discussed, and test results are presented.

  13. Automation of orbit determination functions for National Aeronautics and Space Administration (NASA)-supported satellite missions

    NASA Technical Reports Server (NTRS)

    Mardirossian, H.; Heuerman, K.; Beri, A.; Samii, M. V.; Doll, C. E.

    1989-01-01

    The Flight Dynamics Facility (FDF) at Goddard Space Flight Center (GSFC) provides spacecraft trajectory determination for a wide variety of National Aeronautics and Space Administration (NASA)-supported satellite missions, using the Tracking Data Relay Satellite System (TDRSS) and Ground Spaceflight and Tracking Data Network (GSTDN). To take advantage of computerized decision making processes that can be used in spacecraft navigation, the Orbit Determination Automation System (ODAS) was designed, developed, and implemented as a prototype system to automate orbit determination (OD) and orbit quality assurance (QA) functions performed by orbit operations. Based on a machine-resident generic schedule and predetermined mission-dependent QA criteria, ODAS autonomously activates an interface with the existing trajectory determination system using a batch least-squares differential correction algorithm to perform the basic OD functions. The computational parameters determined during the OD are processed to make computerized decisions regarding QA, and a controlled recovery process isactivated when the criteria are not satisfied. The complete cycle is autonomous and continuous. ODAS was extensively tested for performance under conditions resembling actual operational conditions and found to be effective and reliable for extended autonomous OD. Details of the system structure and function are discussed, and test results are presented.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Schertler, Ronald J.; Gedney, Richard T.

    1992-01-01

    An overview of the NASA ACTS program is presented. The key technologies of ACTS include spot beams, on-board baseband processing and routing, wide bandwidth (900 MHz), and Ka-band transponders. The discussion covers system description, current status of the spacecraft development, ACTS earth stations, NGS traffic terminal, USAT, land and aeronautical mobiles, high data rate and propagation receive only terminals, and ACTS experiments program.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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…

  5. 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…

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

    NASA Technical Reports Server (NTRS)

    Hoder, Douglas; Bergamo, Marcos

    1996-01-01

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

  8. Communications Satellites: Countdown for INTELSAT VI.

    PubMed

    Pollack, L; Weiss, H

    1984-02-10

    Since the formation of COMSAT 20 years ago, the number of international telephone circuits made through satellites has grown 400 times and the cost of a telephone call has decreased by 12,000 percent. Worldwide communications linking 109 nations are achieved with 14 satellites in earth-synchronous orbit. Advances in microwave technology have expanded the transmission bandwidth per satellite from 50 to more than 3000 megahertz. Improvements in solar cell, battery, stationkeeping, and microwave amplification technology have increased satellite lifetime from 1.5 years to 10. The sixth generation of INTELSAT satellites, now being manufactured, will be introduced into the system in 1986, and each satellite will carry more than 40,000 telephone channels plus two television programs. The next generation of satellites, now under design for expanded capacity, will be needed by the middle 1990's to meet the traffic demand. These satellites are likely to add new frequencies (20 and 30 gigahertz), onboard signal processing and switching, and more bandwidth-efficient modulation, to achieve larger communication capacity at each orbital location.

  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. 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.

  11. A new RF package suitable for aeronautical commercial and DSCS satellite applications

    NASA Technical Reports Server (NTRS)

    Hamilton, Robert J., Jr.

    1995-01-01

    Higher levels of integration through the use of GaAs and silicon MMIC devices, a die-cast housing, and the reduction of the number of subassemblies has enabled a large reduction of the size and weight of the electronics package for commercial and military satellite communications. This paper presents an electronics architecture and hardware that utilizes many new integrated circuits and design techniques, and allows flexibility for future satellite frequency changes and expansion. Key features of the radio are extended C-band, InSat, Defense Satellite Communications System (DSCS), and Ku-band coverage options; 70 (or 140) MHz transponder bandwidth or L-band block bandwidth IFs; integrated RS-232 control through local handheld terminal or remote computer; remote control of crystal reference oscillator for aging and temperature compensation; integrated 2 or 5 watt solid-state power amplifiers (SSPA); optional integrated solid-state booster amplifiers to 40 watts; optional external amplifiers to 100 watts; integral beacon tracking with second integrated downcoverter for antenna positioning; radio, including low-noise block converter (LNB) and SSPA, weighs 8.5 kg and measures 32 x 23 x 16.5 cm; environmentally ruggedized for -40 to +60 C; O-ring sealed for waterproofing; passive (convection) cooling; and simple cabling and installation, with a single cable between radio and LNB, and two cables between radio and IF interface. The small size and light weight of the radio make it ideal for mounting on stabilized antenna platforms (gyroscopic or servo). Several input power options (110 or 220 VAC; +48, +12, or -24 VDC) facilitate operation on multiple platforms.

  12. Satellite systems for land mobile communications

    NASA Astrophysics Data System (ADS)

    Iida, T.

    1980-03-01

    Two satellite systems for land mobile communications are proposed: an independent system accommodating 400,000 mobile radios in the 8 GHz band, and a system designed to complement an existing terrestrial mobile radio network using the 900 MHz band and accommodating 50,000 mobile radios. The independent system makes use of a 2000 kg satellite and a multibeam 8.7 m dish antenna. The complementary system has a smaller satellite (800 kg) and a 14.5 m dish antenna. The costs of the two systems are analyzed and compared.

  13. Handbook on satellite communications and broadcasting

    NASA Astrophysics Data System (ADS)

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

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

  14. 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.

  15. 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.

  16. 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.

  17. 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

  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. Architectural trends in military satellite communications systems

    NASA Astrophysics Data System (ADS)

    Jain, Pravin C.

    1990-07-01

    A historical overview of military communications by satellites and a detailed description of current systems are provided. The capabilities of present systems are reviewed in relation to user requirements and threats. It is concluded that use of satellite communications by a large number of small-terminal users (aircraft, ships, submarines, and land mobiles) still requires major technological innovations to meet needs for a substantial increase in system capacity and performance improvements in a jamming environment. The next-generation systems of the 1990s are reviewed with emphasis placed on the discussion of extremely-high-frequency (EHF) systems. Architectural trends are investigated for the post-2000 era. Alternative directions for future systems development, such as the use of highly proliferated satellite constellations, are explored.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Potential markets for advanced satellite communications

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  5. 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.

  6. 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.

  7. New TDRSS communications options for small satellites

    NASA Technical Reports Server (NTRS)

    Zillig, David J.; Perko, Kenneth L.; Nelson, Kathryn G.

    1996-01-01

    The NASA uses a space network which includes the tracking and data relay satellite system (TDRSS) for the provision of reliable low data rate and high data rate relay services between user spacecraft in earth orbit and the ground. In relation to future small satellite designs, new communication options for the TDRSS support of small spacecraft missions are reported on. The technologies considered include new transponder technologies, evolution to Ka band frequencies and a TDRSS demand access service capability. Multiple access aspects are considered.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Hall Thruster Satellite Communication Impact Analysis

    NASA Astrophysics Data System (ADS)

    Hallock, G. A.; Wiley, J. C.; Khanna, A.; Spencer, E. A.

    1999-11-01

    A critical issue which arises in the integration of Hall thruster technology for communication satellite stationkeeping is refraction of the microwave signals caused by the highly ionized plasma plume. This can cause pointing error, sidelobe degradation, and other changes to the antenna pattern. We have developed vector ray tracing codes, which track the trajectory, amplitude, phase, and polarization of a bundle of rays from the antenna reflector or feed. Shaped reflectors are used in modern satellites to tailor the antenna pattern to the desired receiving area. We are investigating the distortion to these patterns caused by thrusters located at various orientations. Hall thrusters exhibit several plasma instabilities, such as drift waves and transit time oscillations. This can introduce phase noise in the communication signals, which is highly undesirable, especially for digital signals. We are modeling these instabilities, which will be added to our simulations. Our codes make use of client/server software, allowing easy configuration setup and web access.

  15. 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.

  16. Modular approach for satellite communication ground terminals

    NASA Technical Reports Server (NTRS)

    Gould, G. R.

    1984-01-01

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

  17. 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.

  18. 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.

  19. 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.

  20. Space Power for Communication Satellites Beyond 1995

    NASA Technical Reports Server (NTRS)

    Pierce, P. R.

    1984-01-01

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

  1. 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.

  2. 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).

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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…

  8. The future of European Communications Satellites

    NASA Astrophysics Data System (ADS)

    Morris, R.

    1984-02-01

    The paper, which is based on the work of a Eurospace Study Group on future prospects, reviews the problems arising from the introduction of new technologies in the industrial process of developing and manufacturing communications satellites, covering the topics of engineering, manufacturing, integration and test, and in-space management. It continues by considering the commerical and industrial problems encountered by European manufacturers, and the contractual and legal problems arising from the change of customer base, from ESA to user organizations, and from the political problems which stem from cross-border transmission of TV broadcasting and data transfer. It then considers the marketing problems of the spacecraft manufacturer - his remoteness from the end-user of telecommunications circuits, the competition from new technology in conventional communications, and the intense competition from U.S. competitors, who have the advantage of both military and domestic and international civil programs on which to develop technology. It concludes with a brief review of current and future spacecraft developments by British Aerospace, and some possible communications satellite configurations for the 1990's.

  9. 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.

  10. High accuracy deployable antenna for communications satellite

    NASA Astrophysics Data System (ADS)

    Watanabe, M.; Misawa, M.; Minomo, M.; Yasaka, T.

    High frequency multi-beam satellite antennas have been studied to realize increased communication capacity, simplified earth stations, and multiple frequency reuse. The satellite antenna needs a highly accurate and large reflector. To overcome the launching vehicle's constraints in size and weight, a solid deployable antenna is under development. A petal antenna (PETAL), composed of solid shell elements, has been studied as a high frequency use deployable antenna. It is an axi-symmetric antenna composed of a fixed central shell and deployable triangular and square shells. During the launch phase, a restraining cable is bound around the periphery of deployable elements stowed in a hexagonal configuration. Deployment is initiated by pyrotechnic cable cutters, and the shells are deployed by spring action.

  11. 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.

  12. 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.

  13. 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.

  14. Delivery of Instructional Materials Using a Communications Satellite.

    ERIC Educational Resources Information Center

    Bransford, Louis A.; Diebler, Mary

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

  15. Aeronautical Communications Research and Development Needs for Future Air Traffic Management Applications

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.

    2002-01-01

    Continuing growth in regional and global air travel has resulted in increasing traffic congestion in the air and on the ground. In spite of occasional temporary downturns due to economic recessions and catastrophic events, average growth rates of air travel have remained high since the 1960s. The resulting congestion, which constrains expansion of the air transportation industry, inflicts schedule delays and decreases overall system efficiency, creating a pressing need to develop more efficient methods of air traffic management (ATM). New ATM techniques, procedures, air space automation methods, and decision support tools are being researched and developed for deployment in time frames stretching from the next few years to the year 2020 and beyond. As these methods become more advanced and increase in complexity, the requirements for information generation, sharing and transfer among the relevant entities in the ATM system increase dramatically. However, current aeronautical communications systems will be inadequate to meet the future information transfer demands created by these advanced ATM systems. Therefore, the NASA Glenn Research Center is undertaking research programs to develop communication, methods and key technologies that can meet these future requirements. As part of this process, studies, workshops, testing and experimentation, and research and analysis have established a number of research and technology development needs. The purpose of this paper is to outline the critical research and technology needs that have been identified in these activities, and explain how these needs have been determined.

  16. A 32 KBPS codec for satellite communication

    NASA Astrophysics Data System (ADS)

    Nishitani, T.; Aikoh, S.; Maruta, R.; Sawai, A.; Shimoyama, H.; Tomozawa, A.

    A 32 kbps ADPCM codec has been developed by combining a robust predictor with a predictor-driven locking quantizer. The algorithm has been chosen through careful studies on combinations of several prediction algorithms and a dynamic locking quantization scheme. By introducing a new speech and data discrimination function in the prediction algorithm, high performance encoding capability very close to that for 64 kbps PCM on both speech and modem signals has been realized without losing robustness in its ability to operate properly in spite of transmission bit errors. This codec enables channel capacity doubling in any digital network, including satellite communications.

  17. 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.

  18. 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.

  19. A new antenna concept for satellite communications

    NASA Technical Reports Server (NTRS)

    Skahill, G.; Ciccolella, D.

    1982-01-01

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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

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

    ERIC Educational Resources Information Center

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

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

  5. The National Aeronautics and Space Administration (NASA) Tracking and Data Relay Satellite System (TDRSS) program Economic and programmatic, considerations

    NASA Technical Reports Server (NTRS)

    Aller, R. O.

    1985-01-01

    The Tracking and Data Relay Satellite System (TDRSS) represents the principal element of a new space-based tracking and communication network which will support NASA spaceflight missions in low earth orbit. In its complete configuration, the TDRSS network will include a space segment consisting of three highly specialized communication satellites in geosynchronous orbit, a ground segment consisting of an earth terminal, and associated data handling and control facilities. The TDRSS network has the objective to provide communication and data relay services between the earth-orbiting spacecraft and their ground-based mission control and data handling centers. The first TDRSS spacecraft has been now in service for two years. The present paper is concerned with the TDRSS experience from the perspective of the various programmatic and economic considerations which relate to the program.

  6. The National Aeronautics and Space Administration (NASA) Tracking and Data Relay Satellite System (TDRSS) program Economic and programmatic, considerations

    NASA Astrophysics Data System (ADS)

    Aller, R. O.

    1985-10-01

    The Tracking and Data Relay Satellite System (TDRSS) represents the principal element of a new space-based tracking and communication network which will support NASA spaceflight missions in low earth orbit. In its complete configuration, the TDRSS network will include a space segment consisting of three highly specialized communication satellites in geosynchronous orbit, a ground segment consisting of an earth terminal, and associated data handling and control facilities. The TDRSS network has the objective to provide communication and data relay services between the earth-orbiting spacecraft and their ground-based mission control and data handling centers. The first TDRSS spacecraft has been now in service for two years. The present paper is concerned with the TDRSS experience from the perspective of the various programmatic and economic considerations which relate to the program.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Advanced high capacity domestic satellite communications system

    NASA Astrophysics Data System (ADS)

    Iso, A.; Kohiyama, K.; Odate, H.; Ishida, N.

    1981-09-01

    The high capacity transmission of a 30/20 GHz and 50/40 GHz domestic satellite communication system is presented with an investigation of the relationship between satellite antenna pointing accuracy, multibeam antenna interference, and multisatellite interference. Antenna pointing is found to affect an antenna's gain and pattern and multibeam interference; thus the antenna beam width is defined to include antenna pointing accuracy. Results include a 6 m antenna gain of 69.5 dB at 20 GHz for 114 beams with a pointing accuracy of 0.05 deg, and a 17.6 m gain of 69.0 dB at 20 GHz for 630 beams with an accuracy of 0.01 deg. The frequency reuse number is given as a function of total beam number and pointing accuracy, and a bandwidth of 7 GHz allocated at 30/20 and 50/40 GHz is made possible by multispot beam antennas and linearly polarized waves.

  17. 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…

  18. 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…

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Laser crosslink configurations for RF satellite communications systems

    NASA Astrophysics Data System (ADS)

    Sebacher, K. S.; Lambert, S. G.; Pautler, J. A.; Carter, J. P.

    Predictions of future satellite communications traffic indicate that an increased capacity for satellite communications systems is required. Crosslinks between satellites provide improvements in communications throughput for these systems. Crosslinks also increase system flexibility and remove the dependence of world-wide information flow on relay ground stations located outside the continental United States. Laser crosslinks provide the additional advantage of eliminating susceptibility to space-based or ground-based jammers. Laser terminals are also smaller and require smaller antennas than an RF terminal. This paper describes the advantages of adding laser crosslinks to RF satellite communications systems. Characteristics of the required RF/optical interfaces on-board the satellites are addessed. Terminal configurations that provide reliable, accurate laser communications at high data rates are described.

  6. 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.

  7. 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.

  8. 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.

  9. Design trade-offs in antijam military satellite communications

    NASA Astrophysics Data System (ADS)

    Brandon, W. T.

    1982-07-01

    Military satellite communications system technical parameters, boundary values and anti-jamming trade-offs among parameters are described and discussed. These systems, which have become essential elements of command, control and communication structures for the U.S., NATO and the Soviet Union, are characterized by such features as global connectivity of commanders and forces, and instant reconfiguration which allows a single system to support services as varied as broadcasting, point-to-point voice communication, and teletype data, for tactical, strategic or logistic users. Attention is given to the anti-jamming concept of satellite position uncertainty, in which a group of satellites functions as uplink receiver, and a single, larger satellite is used as a downlink transmitter. It is shown that, by constraining design to a finite number of satellite orbits, frequency bands and satellite and terminal designs, a practical number of about 5000 different system designs can be stipulated for further study.

  10. 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.

  11. 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.

  12. An electro-optical communications satellite transponder

    NASA Astrophysics Data System (ADS)

    Goldman, A. M., Jr.

    The design concept of an electrooptical transponder for communications satellites operating in C-band or Ku-band is presented. A system comprising 12 single-polarization transponders 36-MHz wide is illustrated with a block diagram. The RF carrier uplink signal passes through a low-noise GaAs FET amplifier and is translated to the downlink RF frequency by a mixer and local oscillator; this signal then serves as a subcarrier to intensity modulate an 850-nm GaAlAs semiconductor laser, and the optical signal is optically switched via fiber, demodulated by pin diode or avalanche photodiode, and passed through a GaAs FET preamplifier and amplifier for downlink transmission. Both prefiber and postfiber component groups can be integrated onto monolithic electrooptical chips operating at very low power. Additional features and design options are discussed; the frequency variation involved (12 decades) is illustrated; and the optical switching speed is shown to be noncritical in present TDMA, SS/TDMA, or FDMA configurations.

  13. Satellite communications application to Pacific countries above Ku band

    NASA Astrophysics Data System (ADS)

    Iida, Takashi

    1992-08-01

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

  14. Satellite communications application to Pacific countries above Ku band

    NASA Technical Reports Server (NTRS)

    Iida, Takashi

    1992-01-01

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

  15. 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.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1991-09-01

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

  18. A novel approach for simulating the optical misalignment caused by satellite platform vibration in the ground test of satellite optical communication systems.

    PubMed

    Wang, Qiang; Tan, Liying; Ma, Jing; Yu, Siyuan; Jiang, Yijun

    2012-01-16

    Satellite platform vibration causes the misalignment between incident direction of the beacon and optical axis of the satellite optical communication system, which also leads to the instability of the laser link and reduces the precision of the system. So how to simulate the satellite platform vibration is a very important work in the ground test of satellite optical communication systems. In general, a vibration device is used for simulating the satellite platform vibration, but the simulation effect is not ideal because of the limited randomness. An approach is reasonable, which uses a natural random process for simulating the satellite platform vibration. In this paper, we discuss feasibility of the concept that the effect of angle of arrival fluctuation is taken as an effective simulation of satellite platform vibration in the ground test of the satellite optical communication system. Spectrum characteristic of satellite platform vibration is introduced, referring to the model used by the European Space Agency (ESA) in the SILEX program and that given by National Aeronautics and Space Development Agency (NASDA) of Japan. Spectrum characteristic of angle of arrival fluctuation is analyzed based on the measured data from an 11.16km bi-directional free space laser transmission experiment. Spectrum characteristic of these two effects is compared. The results show that spectra of these two effects have similar variation trend with the variation of frequency and feasibility of the concept is proved by the comparison results. At last the procedure of this method is proposed, which uses the power spectra of angle of arrival fluctuation to simulate that of the satellite platform vibration. The new approach is good for the ground test of satellite optical communication systems. PMID:22274450

  19. A novel approach for simulating the optical misalignment caused by satellite platform vibration in the ground test of satellite optical communication systems.

    PubMed

    Wang, Qiang; Tan, Liying; Ma, Jing; Yu, Siyuan; Jiang, Yijun

    2012-01-16

    Satellite platform vibration causes the misalignment between incident direction of the beacon and optical axis of the satellite optical communication system, which also leads to the instability of the laser link and reduces the precision of the system. So how to simulate the satellite platform vibration is a very important work in the ground test of satellite optical communication systems. In general, a vibration device is used for simulating the satellite platform vibration, but the simulation effect is not ideal because of the limited randomness. An approach is reasonable, which uses a natural random process for simulating the satellite platform vibration. In this paper, we discuss feasibility of the concept that the effect of angle of arrival fluctuation is taken as an effective simulation of satellite platform vibration in the ground test of the satellite optical communication system. Spectrum characteristic of satellite platform vibration is introduced, referring to the model used by the European Space Agency (ESA) in the SILEX program and that given by National Aeronautics and Space Development Agency (NASDA) of Japan. Spectrum characteristic of angle of arrival fluctuation is analyzed based on the measured data from an 11.16km bi-directional free space laser transmission experiment. Spectrum characteristic of these two effects is compared. The results show that spectra of these two effects have similar variation trend with the variation of frequency and feasibility of the concept is proved by the comparison results. At last the procedure of this method is proposed, which uses the power spectra of angle of arrival fluctuation to simulate that of the satellite platform vibration. The new approach is good for the ground test of satellite optical communication systems.

  20. 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.

  1. Advanced communication satellites worldwide - Satellites of opportunity for the ACTS mobile terminal

    NASA Technical Reports Server (NTRS)

    Girardey, Catherine C.

    1993-01-01

    Space agencies worldwide are involved in advanced satellite communication systems. This paper presents an overview of these satellites and related technologies in the U.S., Europe, and Japan. They are geostationary satellites using high frequency bands such as K/Ka (20/30 GHz) and O-band (millimeter wave), as well as optical frequencies. The similarity of these programs demonstrate a common interest to develop large capacity satellite communication systems, and shows that closer international cooperation could be set up. The ACTS Mobile Terminal (AMT) project discussed here is such an example. The AMT's compatibility with satellites other than ACTS has been studied, and a proposed common experiment is presented here. The Japanese Engineering Test Satellite ETS-VI has been identified as the best initial 'satellite of opportunity' for AMT in this preliminary assessment.

  2. 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.

  3. Future outlook on international satellite communications in Asia Pacific region

    NASA Astrophysics Data System (ADS)

    Itou, Yasuhiko

    1993-03-01

    An overview of the present status and a future trend of the international satellite communication in the Asia Pacific region is presented. The measures to solve the problems of the low penetration of the VSAT (Very Small Aperture Terminal) for international communication; the lack of standardization between different countries; regulatory difficulties and the lack of suitable satellite systems, including CCIR (Comite Consultatif International des Radio-communications) recommendations; and possibility of digital video transmission for SNG (Satellite News Gathering) are discussed. The present status and new technologies of, and satellite orbits (LEO (Low Earth Orbit)), ICO (Intermediate Circular Orbit), and GEO (Geostationary Earth Orbit)) for marine, mobile, and personal communication by hand-carried equipment are outlined.

  4. Estimation Of Interference In Satellite/Ground Communications

    NASA Technical Reports Server (NTRS)

    Kantak, Anil V.

    1990-01-01

    Relative strengths of desired and interfering signals computed for known orbits. Satellite Interference Analysis and Simulation Using Personal Computers (AKSATINT) computer program calculates interference experienced by generic satellite communications receiving station from interfering satellite. Also computes interference-to-signal-power ratio, taking into account losses suffered by links. Of general use to designers of systems and managers of frequencies in selecting proper frequencies under interference scenarios. Written in BASIC.

  5. 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.

  6. 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).

  7. 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…

  8. 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.

  9. Use of advanced solar cells for commercial communication satellites

    NASA Astrophysics Data System (ADS)

    Bailey, Sheila G.; Landis, Geoffrey A.

    1995-03-01

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

  10. Use of advanced solar cells for commerical communication satellites

    NASA Astrophysics Data System (ADS)

    Landis, Geoffrey A.; Bailey, Sheila G.

    1995-01-01

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

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

    PubMed

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

    2010-05-01

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

  12. 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.

  13. Applications of Communications Satellites in Higher Education.

    ERIC Educational Resources Information Center

    Morgan, Robert P.

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

  14. Mobile satellite communications in the 1990's

    NASA Astrophysics Data System (ADS)

    Singh, Jai

    1992-07-01

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

  15. Hard ACTS to follow. [NASA Advanced Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Moy, L.

    1986-01-01

    The Advanced Communications Technology Satellite (ACTS), the third phase of NASA's 30/20 GHz satellite communications program, is praised for its frugal usage of both the geosynchronous orbital arch and the frequency spectrum resources necessary for communications satellites. Its objective is to verify Ka-band satellite communications concepts and to develop a flight and ground system for validation of the multibeam communications proof-of-concept technologies. The ACTS ground segment (comprised of four types of terminals) is designed to compliment the spacecraft for the SS launch in 1989. Precise coordination between the ground and spacecraft segments is performed by the baseband processor (BBP), which is an in-orbit switchboard, and the tracking error word, which enables the ground terminals to remain synchronized with onboard timing. Fixed spot beams and scan beams, comprising the two types of spot beams used, both operate at the same frequency and hence, conserve frequency resources. In addition, the time division multiple access serves to enhance system efficiency. It is concluded that Ka-band satellites are a practical approach to the better usage of those resources potentially threatened by communications satellites. Comprehensive graphs and block diagrams of the system are included.

  16. 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…

  17. 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…

  18. 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…

  19. 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.

  20. 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.

  1. 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.

  2. Availability of a communications satellite - Requirement and feasibility

    NASA Technical Reports Server (NTRS)

    Gordon, G. D.

    1975-01-01

    An estimated 45 communications satellites will be in geostationary orbit in the 1980s. Based on past history, half of the subsystem failures will be due to design failures. Methods now used to achieve present availabilities are summarized in this paper. To increase the availability of a single satellite to 99.99%, new techniques are needed; several possibilities are suggested herein. New developments, including nickel-hydrogen batteries, magnetic bearings, and solid-state amplifiers, are possible solutions to long standing problem areas in communications satellites. Launching a satellite two or three years before the system is needed is one way to reduce design failures in subsequent satellites. Diversity of manufacture can be used to obtain the maximum advantage from redundant elements. Finally, unmanned module exchange at geostationary orbit has been shown to be technically feasible.

  3. 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.

  4. 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.

  5. 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.

  6. Satellite systems requirements for land mobile communications

    NASA Technical Reports Server (NTRS)

    Horstein, M.

    1983-01-01

    The system design objective is to provide a satellite link through a gateway station, connecting mobile users in areas not served by a terrestrial cellular system to the switched telephone network (STN). The proposed frequency allocation comprises a pair of 10-MHz bands in the 806-890 MHz range specified by the 1979 World Administrative Radio Conference (WARC) for land-mobile satellite service (LMSS). The satellite design is constrained by projected STS capability with an upper stage of the wide-body Centaur or Integral Propulsion System (IPS) type. For the latter (a TRW design), the payload is limited to approximately 10,400 lb. The design is to be based on 1990's technology, with initial operating capability scheduled for 1995. The satellite should be designed for a 7-year life. Mobile-unit compatibility with cellular system specifications is desirable, if consistent with other system requirements.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1982-12-01

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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

    Zhilin, Viktor A.

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

  16. 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.

  17. 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

  18. Advances in MMIC technology for communications satellites

    NASA Technical Reports Server (NTRS)

    Leonard, Regis F.

    1992-01-01

    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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. L-Band Digital Aeronautical Communications System Engineering - Initial Safety and Security Risk Assessment and Mitigation

    NASA Technical Reports Server (NTRS)

    Zelkin, Natalie; Henriksen, Stephen

    2011-01-01

    This document is being provided as part of ITT's NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: "New ATM Requirements--Future Communications, C-Band and L-Band Communications Standard Development." ITT has completed a safety hazard analysis providing a preliminary safety assessment for the proposed L-band (960 to 1164 MHz) terrestrial en route communications system. The assessment was performed following the guidelines outlined in the Federal Aviation Administration Safety Risk Management Guidance for System Acquisitions document. The safety analysis did not identify any hazards with an unacceptable risk, though a number of hazards with a medium risk were documented. This effort represents a preliminary safety hazard analysis and notes the triggers for risk reassessment. A detailed safety hazards analysis is recommended as a follow-on activity to assess particular components of the L-band communication system after the technology is chosen and system rollout timing is determined. The security risk analysis resulted in identifying main security threats to the proposed system as well as noting additional threats recommended for a future security analysis conducted at a later stage in the system development process. The document discusses various security controls, including those suggested in the COCR Version 2.0.

  6. L-Band Digital Aeronautical Communications System Engineering - Concepts of Use, Systems Performance, Requirements, and Architectures

    NASA Technical Reports Server (NTRS)

    Zelkin, Natalie; Henriksen, Stephen

    2010-01-01

    This NASA Contractor Report summarizes and documents the work performed to develop concepts of use (ConUse) and high-level system requirements and architecture for the proposed L-band (960 to 1164 MHz) terrestrial en route communications system. This work was completed as a follow-on to the technology assessment conducted by NASA Glenn Research Center and ITT for the Future Communications Study (FCS). ITT assessed air-to-ground (A/G) communications concepts of use and operations presented in relevant NAS-level, international, and NAS-system-level documents to derive the appropriate ConUse relevant to potential A/G communications applications and services for domestic continental airspace. ITT also leveraged prior concepts of use developed during the earlier phases of the FCS. A middle-out functional architecture was adopted by merging the functional system requirements identified in the bottom-up assessment of existing requirements with those derived as a result of the top-down analysis of ConUse and higher level functional requirements. Initial end-to-end system performance requirements were derived to define system capabilities based on the functional requirements and on NAS-SR-1000 and the Operational Performance Assessment conducted as part of the COCR. A high-level notional architecture of the L-DACS supporting A/G communication was derived from the functional architecture and requirements.

  7. Ground stations for aeronautical and space laser communications at German Aerospace Center

    NASA Astrophysics Data System (ADS)

    Moll, Florian; Shrestha, Amita; Fuchs, Christian

    2015-10-01

    Free-space laser communications are subject of current research and development in many research and industrial bodies. Long distance air-ground and space-ground can be implemented in future communication networks as feeder, backbone and backhaul links for various air- and space-based scenarios. The Institute of Communications and Navigation of the German Aerospace Center (DLR) operates two ground stations to investigate the communication channel and system: the Optical Ground Station Oberpfaffenhofen and the Transportable Optical Ground Station. The first one is a fixed installation and operated as experimental station with focus on channel measurements and tests of new developments. Various measurement devices, communication receivers and optical setups may easily be installed for different objectives. The facility is described with its dome installation, telescope setup and infrastructure. Past and current deployment in several projects is described and selected measurement achievements presented. The second ground station is developed for semi-operational use and demonstration purposes. Based on experience with the experimental ground station, this one is developed with higher level of integration and system robustness. The focus application is the space-ground and air-ground downlink of payload data from Earth observation missions. Therefore, it is also designed to be easily transportable for worldwide deployment. The system is explained and main components are discussed. The characteristics of both ground stations are presented and discussed. Further advancements in the equipment and capability are also presented.

  8. 47 CFR 25.216 - Limits on emissions from mobile earth stations for protection of aeronautical radionavigation...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... for protection of aeronautical radionavigation-satellite service. 25.216 Section 25.216 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... radionavigation-satellite service. (a) The e.i.r.p. density of emissions from mobile earth stations placed...

  9. 47 CFR 25.216 - Limits on emissions from mobile earth stations for protection of aeronautical radionavigation...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... for protection of aeronautical radionavigation-satellite service. 25.216 Section 25.216 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... radionavigation-satellite service. (a) The e.i.r.p. density of emissions from mobile earth stations placed...

  10. 47 CFR 25.216 - Limits on emissions from mobile earth stations for protection of aeronautical radionavigation...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... for protection of aeronautical radionavigation-satellite service. 25.216 Section 25.216 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... radionavigation-satellite service. (a) The e.i.r.p. density of emissions from mobile earth stations placed...

  11. 47 CFR 25.216 - Limits on emissions from mobile earth stations for protection of aeronautical radionavigation...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... for protection of aeronautical radionavigation-satellite service. 25.216 Section 25.216 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... radionavigation-satellite service. (a) The e.i.r.p. density of emissions from mobile earth stations placed...

  12. 47 CFR 25.216 - Limits on emissions from mobile earth stations for protection of aeronautical radionavigation...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... for protection of aeronautical radionavigation-satellite service. 25.216 Section 25.216 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... radionavigation-satellite service. (a) The e.i.r.p. density of emissions from mobile earth stations placed...

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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).

  2. A frequency-domain channel model and emulator for aeronautical communications

    NASA Astrophysics Data System (ADS)

    Yang, Xiaopeng; Liang, Jun; Yao, Kun; Shi, Haoshan

    2005-11-01

    In this paper, we propose a frequency domain simulation structure for aeronautical wideband frequency-selective channel, which features ground-air and air-air wireless links. With appropriate channel parameters, the emulator can model the parking, taxi and en-route scenarios. The wideband frequency-selective channel consists of some parallel sub-channels in frequency domain, which are assumed to be independent to each other and have Rayleigh-distributed envelopes. The sub-channel models and emulators are based on a simple structure and characterized by flat fading. Through such decomposition approach, a frequency domain frequency-selective channel model can be achieved, which is suitable for an implementation of orthogonal frequency-division multiplexing (OFDM) or multi-carrier code-division multi-access (MC-CDMA) channel emulator on computer. Some appropriate emulator parameters have been proposed through channel sounding data collected for different scenarios. Particularly, in order to emulate the time-varying fading model well, the parameter sets are generated from time to time before the simulation with the same statistics.

  3. 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.

  4. 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.

  5. 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).

  6. 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.).

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Canadian aeronautical mobile data trials

    NASA Technical Reports Server (NTRS)

    Pedersen, Allister; Pearson, Andrea

    1993-01-01

    This paper describes a series of aeronautical mobile data trials conducted on small aircraft (helicopters and fixed wing) utilizing a low-speed store-and-forward mobile data service. The paper outlines the user requirements for aeronautical mobile satellite communications. 'Flight following' and improved wide-area dispatch communications were identified as high priority requirements. A 'proof-of-concept' trial in a Cessna Skymaster aircraft is described. This trial identified certain development work as essential to the introduction of commercial service including antenna development, power supply modifications and doppler software modifications. Other improvements were also proposed. The initial aeronautical mobile data service available for pre-operational (Beta) trials is outlined. Pre-operational field trials commenced in October 1992 and consisted of installations on a Gralen Communications Inc. Cessna 177 and an Aerospatiale Astar 350 series light single engine helicopter. The paper concludes with a discussion of desirable near term mobile data service developments, commercial benefits, current safety benefits and potential future applications for improved safety.

  12. 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.

  13. 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.

  14. Discrete estimation of continuous angle-modulated signals over multipath channels for aeronautical communication

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    The multipath channel for communication between an aerospace vehicle and a ground terminal is modeled by a multiplicative first-order Markov process. The multiplicative process is treated as a component of the message model and the discrete-time demodulation algorithms using the extended Kalman nonlinear estimation technique are developed for continuous-time angle-modulated signals. The equivalent baseband form of the demodulator structure is derived. Two examples of the message process are discussed for an FM system. The simulation results are presented for various values of the bandwidth expansion ratio and the additive SNR. The performance of the baseband algorithms is discussed.

  15. The use of digital signal processing in satellite communication

    NASA Astrophysics Data System (ADS)

    Bramwell, Jonathan Richard

    1988-06-01

    The recent emphasis on information technology has increased the need for methods of data communications with a greater interest in the areas of satellite communications. Data communications over a satellite can be easily achieved by the use of excessive power and bandwidth but efficient management of the satellite resource requires more elegant means of transmission. The optimum modulator and demodulator can be described by mathematical expressions to represent the physical processes that are required to transmit and receive a signal. Digital signal processing circuits can be used to implement these mathematical functions and once correctly designed are not susceptible to variations in accuracy and hence can maintain an accurate representation of the mathematical model. This thesis documents an investigation into the algorithms and techniques that can be used in the digital implementation of a satellite data modem. The technique used for carrier phase recovery and data decoding is a major variation on a method proposed by Viterbi and Viterbi and relies on phase estimation instead of the more common carrier regeneration techniques. A computer simulation of this algorithm and its performance is described and the overall performance of the simulation is compared to theoretical analysis and experimental performance of a multi-data rate satellite modem covering data rates in the range of 16 Ksymbol/sec to 256 Ksymbol/sec in both the BPSK and QPSK data formats.

  16. 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.

  17. 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.

  18. 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

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

    NASA Technical Reports Server (NTRS)

    Chakraborty, Dayamoy

    1994-01-01

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

  20. Communications technology satellite output-tube design and development

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  1. 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.

  2. 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.

  3. 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.

  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. New techniques in communications satellites and their implications

    NASA Astrophysics Data System (ADS)

    Hockeimer, H. E.

    Advances in communications technologies featured on Intelsat V are reviewed and used as an indicator for further progress through the 1980s. Each Intelsat spacecraft, and there will be 12-15 of them, has 12,000 two-way voice links and two television channels. The satellites feature three-axis stabilization, multiple beam antennas, interband connectivity, metal-hydride batteries, and a low-mass communications filter multiplexer. The structures feature the use of graphite-fiber reinforced composites and electrothermal monopropellant thrusters for stationkeeping chores. Intelsat VI satellites, intended for launch in 1986, will triple the Intelsat capabilities, use millimeter waves, solid-state power amplifiers, microprocessor-based data-handling equipment, have bipropellant propulsion systems, and an intersatellite link operating at RF and optical frequencies. A necessity is asserted for assuring the profitability of the satellite manufacturing industry.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. [NASA/DOD Aerospace Knowledge Diffusion Research Project. Report 1, part 1:] Technical communications in aeronautics: Results of an exploratory study

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Glassman, Myron; Oliu, Walter E.; Barclay, Rebecca O.

    1989-01-01

    A study was undertaken that explored several aspects of technical communications in aeronautics. The study, which utilized survey research in the form of a self-administered questionnaire, was sent to 2,000 randomly selected members of the American Institute of Aeronautics and Astronautics. Six hundred and six usable questionnaires (30.3 percent) were received by the established cut off date. The study had five objectives. The first was to solicit the opinions of aeronautical engineers and scientists regarding the importance of technical communications to their profession; second, to determine their use and production of technical communications; third, to seek their views on the content of an undergraduate course in technical communications; fourth, to determine their use of libraries/technical information centers; and finally, to determine the use and importance of computer and information technology to them. The findings add considerable information to the knowledge of technical communications practices among aeronautical engineers and scientists and reinforce some of the conventional wisdom about technical communications and question other widely-held notions.

  12. 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…

  13. 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…

  14. 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.

  15. 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

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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.

  2. 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.

  3. A Low Earth Orbit satellite marine communication system demonstration

    NASA Technical Reports Server (NTRS)

    Elms, T. Keith; Butt, Kenneth A.; Asmus, Ken W.

    1995-01-01

    An application of Low Earth Orbit (LEO) satellite communications technology was investigated during a joint Canadian/American scientific expedition to the north pole in the summer of 1994. The Canadian ice breaker involved, was equipped with a store-and-forward LEO satellite terminal which was linked to a ground station in St. John's, Newfoundland, via the near-polar-orbiting satellite, HealthSat-l. The objective was to evaluate the performance of such a system while providing an alternate means of communications in the far north. The system performed well, given its inherent limitations. All 151 attempts to send data files to the ship were successful. Only two (2) of the 35 attempts to send files from the ship were unsuccessful. The files ranged in size from 0.1 to 60 Kbytes. In the high arctic, above 80 deg north, this system often provided the only practical means of data communications. This experiment demonstrated the potential of such a system for not-real-time communications with remote and/or mobile stations, and highlighted the many issues involved. This paper describes the project objectives, system configuration and experimental procedure used, related technical issues, trial results, future work, and conclusions.

  4. 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.

  5. 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...

  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. Planning satellite communication services and spectrum-orbit utilization

    NASA Technical Reports Server (NTRS)

    Sawitz, P. H.

    1982-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Potter, J. G.

    1978-01-01

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

  9. Channel simulation to facilitate mobile-satellite communications research

    NASA Technical Reports Server (NTRS)

    Davarian, Faramaz

    1987-01-01

    The mobile-satellite-service channel simulator, which is a facility for an end-to-end hardware simulation of mobile satellite communications links is discussed. Propagation effects, Doppler, interference, band limiting, satellite nonlinearity, and thermal noise have been incorporated into the simulator. The propagation environment in which the simulator needs to operate and the architecture of the simulator are described. The simulator is composed of: a mobile/fixed transmitter, interference transmitters, a propagation path simulator, a spacecraft, and a fixed/mobile receiver. Data from application experiments conducted with the channel simulator are presented; the noise converison technique to evaluate interference effects, the error floor phenomenon of digital multipath fading links, and the fade margin associated with a noncoherent receiver are examined. Diagrams of the simulator are provided.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Phased-Array Satcom Antennas Developed for Aeronautical Applications

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.

    2001-01-01

    The Advanced Communications (AC) for Aeronautics research at the NASA Glenn Research Center integrates both aeronautics and space communications technologies to achieve the national objective of upgrading the present National Airspace System infrastructure by responding to the agency's aviation capacity and safety goals. One concept for future air traffic management, free flight, presents a significantly increased demand for communications systems capacity and performance in comparison to current air traffic management practices. Current aeronautical communications systems are incapable of supporting the anticipated demands, and the new digital data communications links that are being developed, or are in the early stages of implementation, are not primarily designed to carry the data-intensive free flight air traffic management (ATM) communications loads. Emerging satellite communications technologies are the best potential long-term solution to provide the capacity and performance necessary to enable a mature free flight concept to be deployed. NASA AC/ATM funded the development of a Boeing-designed Ku-band transmit phased-array antenna, a combined in-house and contract effort. Glenn designed and integrated an Aeronautical Mobile Satellite Communications terminal based on the transmit phased-array antenna and a companion receive phased-array antenna previously developed by Boeing.

  1. 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.

  2. OSI-compatible protocols for mobile-satellite communications: The AMSS experience

    NASA Technical Reports Server (NTRS)

    Moher, Michael

    1990-01-01

    The protocol structure of the international aeronautical mobile satellite service (AMSS) is reviewed with emphasis on those aspects of protocol performance, validation, and conformance which are peculiar to mobile services. This is in part an analysis of what can be learned from the AMSS experience with protocols which is relevant to the design of other mobile satellite data networks, e.g., land mobile.

  3. Assessment of voice coders for ATC/pilot voice communications via satellite digital communication channels

    NASA Astrophysics Data System (ADS)

    Troll, N. L.

    1989-03-01

    An Air Traffic Control (ATC) simulation testbench constructed for the purpose of assessing the use of voice coding equipment (vocoders) for relaying voice communications between air traffic controllers and pilots via satellite digital communication channels is described. The development of the testbench and the analysis procedures is described. Several vocoders employing different coding algorithms which have been proposed for use over satellite data channels are assessed. Within the limitations imposed by the simulation, the assessment suggests that voice coded speech at 8 to 9.6 k bit/sec would be acceptable for some ATC tasks. The assessment results were also used to rank the vocoders for acceptability to support ATC voice communications under various bit error rates over the digital communication channel.

  4. [NASA/DOD Aerospace Knowledge Diffusion Research Project. Report 1, part 2:] Technical communications in aeronautics: Results of an exploratory study

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Glassman, Myron; Oliu, Walter E.; Barclay, Rebecca O.

    1989-01-01

    A study was undertaken that explored several aspects of technical communications in aeronautics. The study, which utilized survey research in the form of a self-administered questionnaire, was sent to 2,000 randomly selected members of the American Institute of Aeronautics and Astronautics. Six hundred and six usable questionnaires (30.3 percent) were received by the established cut off date. Part 2 of this study lists appendices to part 1, including survey instrument, aggregate totals, cross tabulations, and open-ended comments.

  5. 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).

  6. 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.

  7. 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.

  8. 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…

  9. 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…

  10. Hall Thruster Impact Analysis on Satellite Communi-cation

    NASA Astrophysics Data System (ADS)

    Hallock, G. A.; Wiley, J. C.; Khanna, A.; Spencer, E. A.; Meyer, J. W.; Loane, J. T.

    2000-10-01

    Hall thrusters are currently under development for stationkeeping of geosynchrnous communications satellites. These thrusters produce an inhomogeneous plasma plume, which must be carefully evaluated in terms of possible degradation of the microwave communications signals (typ. 1-20 GHz). The electron density on the axis of a 5 kW class Hall thruster at a distance of 1 m is ~ 10^16 m-3, with a gradual decrease off-axis. We have developed a geometrical optics ray tracing code to study the effect of plasma thrusters on communication satellite antennas. The code has recently been enhanced to include the reflector feed and offset reflector antennas. We also analyze shaped reflectors, where the parabolic shape is modified slightly to generate an antenna pattern matched to the desired area of coverage. We will present parametric studies, where the plume-antenna interaction is quantified as a function of separation and geometry. Code development will also be presented, including the quintic pseudospline technique used to interpolate shaped reflector grid points, feed models, and exit plane effects on code accuracy.

  11. 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.

  12. 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.

  13. Study of information transfer optimization for communication satellites

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  14. Two way satellite communication for telemetrology and remote control

    NASA Astrophysics Data System (ADS)

    Hanebrekke, H.

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

  15. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1987-05-01

    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.

  17. 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.

  18. 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.

  19. A CDMA Spotbeam Architecture for the Next Generation Satellite System (NGSS) for the Aeronautical Telecommunications Network (ATN)

    NASA Technical Reports Server (NTRS)

    Raghavan, Rajesh S.; Shamma, Mohammed A.

    2003-01-01

    This paper will present work being done to model and simulate a CDMA based Mobile Satellite System architecture for providing all or part of the future Air Traffic Management (ATM) services. Such a system, will help in relieving the dependence on ground based networks, if not eliminate it. Additionally such an architecture can be used in parallel or as a supplementary service along with ground based links to help alleviate any capacity bottlenecks, or in areas where such services are difficult to make available such as in oceanic, remote areas outside the jet highways, or in developing countries where ground services are less available.

  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. 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.

  2. The use of digital circuit multiplication equipment in satellite communications

    NASA Astrophysics Data System (ADS)

    Viklund, Nils-Erik; Nycander, Claes

    1990-12-01

    The use, within satellite communications, of low rate encoding (LRE) techniques, based on 24, 32 and 40 kb/s ADPCM coding, coupled with digital speech interpolation (DSI) to form a digital circuit multiplication equipment (DCME), is addressed in this paper. The need for a system simulation tool, in order to plan for and correctly use the DCME concept is identified. Results obtained with this simulation tool are presented. The simulation model makes it possible to predict the behavior of the system from a quality point of view, with external conditions simulated to be very close to actual operating conditions.

  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. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Mitigation of weather on channel propagation for satellite communications

    NASA Astrophysics Data System (ADS)

    Shu, Zhihui; Tian, Xin; Wang, Gang; Shen, Dan; Pham, Khanh; Blasch, Erik; Chen, Genshe

    2016-05-01

    This paper investigates weather effects on a satellite communication (SATCOM) link communication channel model. Specifically, rain attenuation in the Ka band and X band of the SATCOM link for both uplink and downlink scenarios are presented. The weather model for the SATCOM link uses a Markov chain model with an average probability and transition probability for different states of weather, to investigate the impact of dynamic weather on the SATCOM link channel propagation model. Also, a power control method is proposed to achieve the required carrier to noise ratio in a SATCOM scenario using a Bayesian Network in Netica. The Bayesian Network models the space-ground link geometry and transmit power control to adapt to the dynamic weather. Simulations are implemented for the weather states during relatively long and short periods, path loss variations, and transmit power distributions over different scenarios. The simulation results demonstrate the effectiveness of the proposed weather model, Markov chain model, and the power control method for SATCOM.

  13. 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…

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

    NASA Technical Reports Server (NTRS)

    Zollars, G. F.

    1980-01-01

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

  15. 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.

  16. 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.

  17. 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.

  18. Protocol Support for a New Satellite-Based Airspace Communication Network

    NASA Technical Reports Server (NTRS)

    Shang, Yadong; Hadjitheodosiou, Michael; Baras, John

    2004-01-01

    We recommend suitable transport protocols for an aeronautical network supporting Internet and data services via satellite. We study the characteristics of an aeronautical satellite hybrid network and focus on the problems that cause dramatically degraded performance of the Transport Protocol. We discuss various extensions to standard TCP that alleviate some of these performance problems. Through simulation, we identify those TCP implementations that can be expected to perform well. Based on the observation that it is difficult for an end-to-end solution to solve these problems effectively, we propose a new TCP-splitting protocol, termed Aeronautical Transport Control Protocol (AeroTCP). The main idea of this protocol is to use a fixed window for flow control and one duplicated acknowledgement (ACK) for fast recovery. Our simulation results show that AeroTCP can maintain higher utilization for the satellite link than end-to-end TCP, especially in high BER environment.

  19. 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.

  20. 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.

  1. EHF dielectric lens antenna for Satellite Communication Systems

    NASA Astrophysics Data System (ADS)

    Rotman, W.

    1983-01-01

    Dielectric lens antennas are applicable to the design of multiple-beam antenna (MBA) systems on EHF communication satellites. Advantages include excellent wide angle scanning properties and elimination of feed blockage. This report describes an experimental 90 lambda dia. zoned dielectric lens, operating at 44 GHz, which was fabricated and tested in order to estimate the performance of a dielectric lens MBA. Measurements showed that the lens generated a beam with a half-power beamwidth (HPBW) of 0.7 deg which could be steered over a total scan angle of 18 deg (corresponding to the Earth's field-of-view from a geosynchronous satellite) with a scanning loss of less than 1 dB and a gain in excess of 47 dBi measured at the sub-satellite point over a 5% bandwidth. A theoretical analysis of the radiation characteristics of the lens antenna, using ray tracing and geometric optics techniques, gave excellent agreement with the measurements. Simplified design equations were developed to facilitate evaluation and development of lens antenna systems of this type.

  2. 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.

  3. NASA aeronautics

    NASA Technical Reports Server (NTRS)

    Anderton, D. A.

    1982-01-01

    Aeronautical research programs are discussed in relation to research methods and the status of the programs. The energy efficient aircraft, STOL aircraft and general aviation aircraft are considered. Aerodynamic concepts, rotary wing aircraft, aircraft safety, noise reduction, and aircraft configurations are among the topics included.

  4. Aeronautic instruments

    NASA Technical Reports Server (NTRS)

    Everling, E; Koppe, H

    1924-01-01

    The development of aeronautic instruments. Vibrations, rapid changes of the conditions of flight and of atmospheric conditions, influence of the air stream all call for particular design and construction of the individual instruments. This is shown by certain examples of individual instruments and of various classes of instruments for measuring pressure, change of altitude, temperature, velocity, inclination and turning or combinations of these.

  5. 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.

  6. 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.

  7. 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).

  8. Advanced Civilian Aeronautical Concepts

    NASA Technical Reports Server (NTRS)

    Bushnell, Dennis M.

    1996-01-01

    Paper discusses alternatives to currently deployed systems which could provide revolutionary improvements in metrics applicable to civilian aeronautics. Specific missions addressed include subsonic transports, supersonic transports and personal aircraft. These alternative systems and concepts are enabled by recent and envisaged advancements in electronics, communications, computing and Designer Fluid Mechanics in conjunction with a design approach employing extensive synergistic interactions between propulsion, aerodynamics and structures.

  9. 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.

  10. 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.

  11. 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

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. K band tracking system for the domestic satellite communication system

    NASA Astrophysics Data System (ADS)

    Kaitsuka, T.; Inoue, T.

    1980-09-01

    The paper is concerned with system design and operational results of a tracking system for an earth station antenna operating in the 20 and 30 GHz bands. The antenna is either an 11.5-m-diam axisymmetrical Cassegrain antenna or an equivalent offset Cassegrain antenna. Monopulse tracking technique using higher-order waveguide modes is utilized. An investigation was conducted to clarify the rainfall effect and the effect of oscillator phase noise on the tracking receiver. The result is that the tracking system can be operated normally even when rain attenuation reaches 20 dB. Experiments were performed using the Medium Capacity Communications Satellite. No cross coupling was seen in the pull-in patterns. Sufficiently good results were obtained in tracking accuracy - less than 0.005 deg (peak value) under normal conditions, and less than 0.01 deg under an average wind velocity of more than 20 m/s.

  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. A novel digital burst demodulator for TDMA satellite communication systems

    NASA Astrophysics Data System (ADS)

    Sakata, Tetsu; Morikura, Masahiro; Kato, Shuzo

    A baseband reverse modulation carrier revovery scheme with phase compensated carrier filters is proposed as a high performance digital burst demodulator for TDMA (Time Division Multiple Access) satellite communication systems. Computer simulations show that the phase acquisition time of the proposed scheme is 90% less than that of the conventional Costas loop scheme, assuming that they have the same carrier cycle slipping rate at an Eb/No of 2dB. Moreover, a novel carrier AFC (Automatic Frequency Control) circuit is proposed to realize simple and digitalized AFC. The proposed AFC circuit reduces the hardware size to 25% of that of a conventional cross product frequency discriminator, and computer simulations show good AFC performance to countermeasure common carrier frequency error.

  20. Spectrum-orbit utilization - An overview. [domestic satellite communication systems

    NASA Technical Reports Server (NTRS)

    Sawitz, P. H.

    1975-01-01

    This paper discusses the problems associated with the efficient utilization of the natural resources of frequency spectrum and geo-stationary orbital arc. The nature of these resources is explained and their quantities are estimated. The present and projected future demand for them is given, and the problem areas are identified and discussed. Special emphasis is placed on mutual interference, launch limitations, propagation effects, and operational restrictions. The technical factors bearing on these problems, such as antenna patterns, modulation methods, emission restrictions, equipment characteristics, and system requirements, are discussed in detail. Some important trade-offs are presented, and special techniques that can be used to increase spectrum-orbit utilization are described. Particular emphasis is given throughout to U.S. domestic satellite communication systems.

  1. 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.

  2. Using Geostationary Communications Satellites as a Sensor: Telemetry Search Algorithms

    NASA Astrophysics Data System (ADS)

    Cahoy, K.; Carlton, A.; Lohmeyer, W. Q.

    2014-12-01

    For decades, operators and manufacturers have collected large amounts of telemetry from geostationary (GEO) communications satellites to monitor system health and performance, yet this data is rarely mined for scientific purposes. The goal of this work is to mine data archives acquired from commercial operators using new algorithms that can detect when a space weather (or non-space weather) event of interest has occurred or is in progress. We have developed algorithms to statistically analyze power amplifier current and temperature telemetry and identify deviations from nominal operations or other trends of interest. We then examine space weather data to see what role, if any, it might have played. We also closely examine both long and short periods of time before an anomaly to determine whether or not the anomaly could have been predicted.

  3. 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.

  4. Optical phase locked loop for transparent inter-satellite communications.

    PubMed

    Herzog, F; Kudielka, K; Erni, D; Bächtold, W

    2005-05-16

    A novel type of optical phase locked loop (OPLL), optimized for homodyne inter-satellite communication, is presented. The loop employs a conventional 180? 3 dB optical hybrid and an AC-coupled balanced front end. No residual carrier transmission is required for phase locking. The loop accepts analog as well as digital data and various modulation formats. The only requirement to the transmitted user signal is a constant envelope. Phase error extraction occurs through applying a small sinusoidal local oscillator (LO) phase disturbance, while measuring its impact on the power of the baseband output signal. First experimental results indicate a receiver sensitivity of 36 photons/bit (-55.7 dBm) for a BER of 10 ;-9, when transmitting a PRBS-31 signal at a data rate of 400 Mbit/s. The system setup employs diode-pumped Nd:YAG lasers at a wavelength of 1.06 mum.

  5. 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

  6. 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.

  7. Aeronautics and Space Report of the President: Fiscal Year 1996 Activities

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Topics considered include: (1) Space launch activities: space shuttle missions; expendable launch vehicles. (2) Space science: astronomy and space physics; solar system exploration. (3) Space flight and technology: life and microgravity sciences; space shuttle technology; reuseable launch vehicles; international space station; energy; safety and mission assurance; commercial development and regulation of space; surveillance. (4) Space communications: communications satellites; space network; ground networks; mission control and data systems. (5) Aeronautical activities: technology developments; air traffic control and navigation; weather-related aeronautical activities; flight safety and security; aviation medicine and human factors. (6) Studies of the planet earth: terrestrial studies and applications: atmospheric studies: oceanographic studies; international aeronautical and space activities; and appendices.

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

    NASA Technical Reports Server (NTRS)

    Golshan, Nassar (Editor)

    1996-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Otsu, Toru; Umehira, Masahiro; Onuki, Masafumi; Nakashima, Hiroshi

    1992-03-01

    This paper describes an advanced satellite communication system for ISDN subscriber and trunk applications that is integrated into a terrestrial ISDN. The system concept of DYANET (DYnamic channel Assigning and routing satellite aided digital NETwork) has been extended to a new platform called DYANET-II which allows satellite communications to be applied to ISDN subscriber lines as well as trunk circuits. New network control technologies have been developed to achieve efficient satellite channel utilization and to ensure a single hop connection of a satellite channel without modifying existing networks. Moreover, compact earth station equipment has been newly developed for use on customer premises.

  10. 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...

  11. 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)

  12. 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…

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1995-05-01

    The United States military gained experience with a deployed telemedicine team and unit during the deployment of United States military troops to Haiti as part of `Operation Uphold Democracy.' Consults were conducted primarily between the 28th combat support hospital in Haiti and Walter Reed Army Medical Center in Washington, D.C. The Advanced Communications Technology Satellite and International Maritime Satellite services were used for telecommunications during the deployment. A total of 30 telemedicine consultations were performed during the deployment. All consultations were conducted prospectively, and data was entered in a database for later review. Treatment plans and plans for patient disposition were recorded prior to consultation. Following completion of the telemedicine consultations, each case was reviewed to determine the impact of the telemedicine consult upon the treatment plan or disposition. Fifty percent of the consultations resulted in a significant modification in the patient's treatment plan. Seventeen percent resulted in a significant or possible change in evacuation planning. The most frequently used consultants were the dermatologists, radiologists, and hand surgeons. This experience demonstrates that telemedicine can be used effectively in a deployed military environment. In addition, the ability to obtain remote consultations does impact upon medical treatment and upon medical evacuation. Having support personnel in the field was found to be an important factor in utilization of the system.

  20. Aeronautics and space report of the President, 1982 activities

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Achievements of the space program are summerized in the area of communication, Earth resources, environment, space sciences, transportation, aeronautics, and space energy. Space program activities of the various deprtments and agencies of the Federal Government are discussed in relation to the agencies' goals and policies. Records of U.S. and world spacecraft launchings, successful U.S. launches for 1982, U.S. launched applications and scientific satellites and space probes since 1975, U.S. and Soviet manned spaceflights since 1961, data on U.S. space launch vehicles, and budget summaries are provided. The national space policy and the aeronautical research and technology policy statements are included.

  1. Western Aeronautical Test Range

    NASA Technical Reports Server (NTRS)

    Sakahara, Robert D.

    2008-01-01

    NASA's Western Aeronautical Test Range (WATR) is a network of facilities used to support aeronautical research, science missions, exploration system concepts, and space operations. The WATR resides at NASA's Dryden Flight Research Center located at Edwards Air Force Base, California. The WATR is a part of NASA's Corporate Management of Aeronautical Facilities and funded by the Strategic Capability Asset Program (SCAP). It is managed by the Aeronautics Test Program (ATP) of the Aeronautics Research Mission Directorate (ARMD) to provide the right facility at the right time. NASA is a tenant on Edwards Air Force Base and has an agreement with the Air Force Flight Test Center to use the land and airspace controlled by the Department of Defense (DoD). The topics include: 1) The WATR supports a variety of vehicles; 2) Dryden shares airspace with the AFFTC; 3) Restricted airspace, corridors, and special use areas are available for experimental aircraft; 4) WATR Products and Services; 5) WATR Support Configuration; 6) Telemetry Tracking; 7) Time Space Positioning; 8) Video; 9) Voice Communication; 10) Mobile Operations Facilities; 11) Data Processing; 12) Mission Control Center; 13) Real-Time Data Analysis; and 14) Range Safety.

  2. 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.

  3. 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.

  4. 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.

  5. 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...

  6. Aeronautics and space report of the President: 1981 activities

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Achievements in the aeronautics and space program by function are summarized. Activities in communications, Earth's resources and environment, space science, space transportation, international activities, and aeronautics are included.

  7. 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.

  8. Game theoretic power allocation and waveform selection for satellite communications

    NASA Astrophysics Data System (ADS)

    Shu, Zhihui; Wang, Gang; Tian, Xin; Shen, Dan; Pham, Khanh; Blasch, Erik; Chen, Genshe

    2015-05-01

    Game theory is a useful method to model interactions between agents with conflicting interests. In this paper, we set up a Game Theoretic Model for Satellite Communications (SATCOM) to solve the interaction between the transmission pair (blue side) and the jammer (red side) to reach a Nash Equilibrium (NE). First, the IFT Game Application Model (iGAM) for SATCOM is formulated to improve the utility of the transmission pair while considering the interference from a jammer. Specifically, in our framework, the frame error rate performance of different modulation and coding schemes is used in the game theoretic solution. Next, the game theoretic analysis shows that the transmission pair can choose the optimal waveform and power given the received power from the jammer. We also describe how the jammer chooses the optimal power given the waveform and power allocation from the transmission pair. Finally, simulations are implemented for the iGAM and the simulation results show the effectiveness of the SATCOM power allocation, waveform selection scheme, and jamming mitigation.

  9. 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.

  10. Characteristics of scale models of large deployable mesh reflector antenna for mobile communications satellites

    NASA Astrophysics Data System (ADS)

    Akaishi, Akira; Orikasa, Teruaki; Kashiki, Kanshiro; Okamoto, Teruki; Otsu, Yuichi; Satoh, Hideo

    1993-10-01

    In the land mobile satellite system (LMSS) using a geostationary platform (GPF), a 30 m diameter satellite antenna is desirable for small portable terminal communications. SCR has adopted two deployment types of antenna structure, the Hexa-Link Truss reflector and the Tetra-Triagonal Prism Truss (TETRUS) reflector, and has developed scale models of them. Both of them represent important aspects of large satellite antenna technology. This paper describes the SCR outline of a land mobile satellite communications system and the experimental results of the scale models. This research establishes the basic technical information necessary for the development of a 30 m diameter antenna and a conceptual GPF design.

  11. Characteristics of scale models of large deployable mesh reflector antennas for mobile communications satellites

    NASA Astrophysics Data System (ADS)

    Akaishi, Akira; Orikasa, Teruaki; Kashiki, Kanshiro; Okamoto, Teruki; Otsu, Yuichi; Satoh, Hideo

    In the land mobile satellite system (LMSS) using a geostationary platform (GPF), a 30 m diameter satellite antenna is desirable for small portable terminal communications. SCR has adopted two deployment types of antenna structure, the Hexa-Link Truss reflector and the Tetra-Triagonal Prism Truss (TETRUS) reflector, and has developed scale models of them. Both of them represent important aspects of large satellite antenna technology. This paper describes the SCR outline of a land mobile satellite communications system and the experimental results of the scale models. This research establishes the basic technical information necessary for the development of a 30 m diameter antenna and a conceptual GPF design.

  12. 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.

  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. Civil and military satellite communications: A systems overview and the future developments

    NASA Astrophysics Data System (ADS)

    Dezaire, J. P.

    1991-02-01

    The project A90KM616, Orientatie SATCOM, is being performed on behalf of the Royal Netherlands Navy (RNLN) to assist the Navy on the subject of satellite communications. An overview is given of the phenomenon satellite communication. The result is a general overview of satellite communications for both civil and military applications. Some examples of applications are; international telephony, television broadcasting, small private business networks, and mobile (at the moment still principally maritime) communications. In these applications satellite communication systems provide a global coverage and a high flexibility. The scientific articles have not been considered because in this stage it was the intention to study on a specialist level the broad area of techniques. Magazines, books, and a number of reports of universities and research institutes have been the main sources of information. They provided afforded an understanding of the existing systems and insight in the future developments.

  15. [Exploring Aeronautics

    NASA Technical Reports Server (NTRS)

    Robinson, Brandi

    2004-01-01

    This summer I have been working with the N.A.S.A. Project at Cuyahoga Community College (Tri-C) under the title of Exploring Aeronautics Project Leader. The class that I have worked with is comprised of students that will enter the eighth grade in the fall of 2004. The program primarily focuses upon math proficiency and individualized class projects. My duties have encompassed both realms. During the first 2-3 weeks of my internship, I worked at NASA Glenn Research Center (GRC) researching, organizing, and compiling information for weekly Scholastic Challenges and the Super Scholastic Challenge. I was able to complete an overview of Scholastic Challenge and staff responsibilities regarding the competition; a proposal for an interactive learning system, Quizdom; a schedule for challenge equipment, as well as a schedule listing submission deadlines for the staff. Also included in my tasks, during these first 2-3 weeks, were assisting Tammy Allen and Candice Thomas with the student application review and interview processes for student applicants. For the student and parent orientation, I was assigned publications and other varying tasks to complete before the start of the program. Upon the commencement of the program, I changed location from NASA GRC to Tri-C Metro Campus, where student classes for the Cleveland site are held. During the duration of the program, I work with the instructor for the Exploring Aeronautics class, kkkk, assisting in classroom management, daily attendance, curriculum, project building, and other tasks as needed. These tasks include the conducting of the weekly competition, known as Scholastic Challenge. As a Project Leader, I am also responsible for one subject area of the Scholastic Challenge aspect of the N.A.S.A. Project curriculum. Each week I have to prepare a mission that the participants will take home the following Monday and at least 10 questions that will be included in the pool of questions used for the Scholastic Challenge

  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. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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)

  3. 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.

  4. 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)

  5. 78 FR 14952 - Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-08

    ... Electronic Comment Filing System (ECFS). See Electronic Filing of Documents in Rulemaking Proceedings, 63 FR... COMMISSION 47 CFR Part 2 Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service.... FOR FURTHER INFORMATION CONTACT: Andrea Kelly, Satellite Division, International Bureau, FCC,...

  6. 78 FR 19172 - Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-29

    ..., FR Doc. 2013-04429, on page 14952, column 1, correct the DATES section to read as follows: DATES... COMMISSION 47 CFR Parts 2 and 25 Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service... Stations Aboard Aircraft. FOR FURTHER INFORMATION CONTACT: Andrea Kelly, Satellite Division,...

  7. 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…

  8. 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…

  9. 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.

  10. 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)

  11. 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.

  12. 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

  13. 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…

  14. Communications Satellites: A Rural Response to the Tyranny of Distance.

    ERIC Educational Resources Information Center

    Jordahl, Gregory

    1989-01-01

    Provides an overview of several current satellites-based instructional systems and assesses their potential role in rural education. Highlights include the Oklahoma Arts and Sciences Teleconferencing Service (ASTS); the Texas Interactive Instructional Network (TI-IN); Washington's Satellite Telecommunications Educational Programming (STEP);…

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Flight and ground tests of a GOES satellite time receiver for satellite communications applications

    NASA Technical Reports Server (NTRS)

    Swanson, R. L.; Nichols, S. A.

    1981-01-01

    A satellite time receiver was tested in various environmental conditions during the past year. The commercial receiver designed to work with the National Oceanic and Atmospheric Administration's (NOAA) Geostationary Operational Environmental Satellites (GOES). The test program included operation at low elevation during flight in a military cargo aircraft and long term comparison with laboratory standards. The GOES satellite time receiver offers an opportunity to provide easy wide area coverage synchronization at low cost.

  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.

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

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  2. 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

  3. Detection and compensation of basis deviation in satellite-to-ground quantum communications.

    PubMed

    Zhang, Ming; Zhang, Liang; Wu, Jincai; Yang, Shiji; Wan, Xiong; He, Zhiping; Jia, Jianjun; Citrin, D S; Wang, Jianyu

    2014-04-21

    Basis deviation is the reference-frame deviation between a sender and receiver caused by satellite motion in satellite-to-ground quantum communications. It increases the quantum-bit error ratio of the system and must be compensated for to guarantee reliable quantum communications. We present a new scheme for compensating for basis deviation that employs a BB84 decoding module to detect basis deviation and half-wave plate to provide compensation. Based on this detection scheme, we design a basis-deviation compensation approach and test its feasibility in a voyage experiment. Unlike other polarization-correction schemes, this compensation scheme is simple, convenient, and can be easily implemented in satellite-to-ground quantum communications without increased burden to the satellite. PMID:24787870

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

    NASA Astrophysics Data System (ADS)

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

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

  5. 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.

  6. Detection and compensation of basis deviation in satellite-to-ground quantum communications.

    PubMed

    Zhang, Ming; Zhang, Liang; Wu, Jincai; Yang, Shiji; Wan, Xiong; He, Zhiping; Jia, Jianjun; Citrin, D S; Wang, Jianyu

    2014-04-21

    Basis deviation is the reference-frame deviation between a sender and receiver caused by satellite motion in satellite-to-ground quantum communications. It increases the quantum-bit error ratio of the system and must be compensated for to guarantee reliable quantum communications. We present a new scheme for compensating for basis deviation that employs a BB84 decoding module to detect basis deviation and half-wave plate to provide compensation. Based on this detection scheme, we design a basis-deviation compensation approach and test its feasibility in a voyage experiment. Unlike other polarization-correction schemes, this compensation scheme is simple, convenient, and can be easily implemented in satellite-to-ground quantum communications without increased burden to the satellite.

  7. 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…

  8. 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…

  9. 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…

  10. Program on Application of Communications Satellites to Educational Development. Progress Report.

    ERIC Educational Resources Information Center

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

    An interdisciplinary program is exploring the educational services which communications satellites may help provide and the synthesis of systems for delivering these services in the United States. From November 1970 to November 1971 substantial progress was made in three primary program categories: needs analysis, communications technology…

  11. The Veterans Administration Experiments in Health Communications on the Applications Technology Satellite (ATS-6). Final Report.

    ERIC Educational Resources Information Center

    Caldwell, Kathryn S.

    Because many of the Veterans Administration hospitals in Appalachia are located great distances from medical teaching facilities, high powered communication satellites have been employed to facilitate quality two-way communication between medical personnel scattered throughout the region. To achieve diagnostic, therapeutic, and educational…

  12. Optimizing Satellite Communications With Adaptive and Phased Array Antennas

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  14. The link availability analysis of GEO satellite-to-ground laser communication

    NASA Astrophysics Data System (ADS)

    Chen, Erhu; Mei, Haiping; Zhang, Changquan; Chang, Chengwu

    2015-08-01

    The performance of satellite-to-ground laser communication is affected by the atmospheric environment seriously, so it is a key issue for system design and operation to analyze the link availability quantitatively according to the channel characteristics. Firstly, the basic concept of laser communication link availability is put forward. Secondly, the preliminary theory model and calculation method of geostationary satellite-to-ground laser communication link availability are established by analyzing influencing factors. Lastly, the link availability of 77°E GEO satellite-to-ground laser communication is analyzed, combining with the atmospheric statistics data of typical optical ground stations in China. The results show that, it is feasible to achieve more than 90% joint link availability by implementing two stations, or to achieve more than 95% joint link availability by implementing three stations.

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

    NASA Technical Reports Server (NTRS)

    Hayase, Joshua Y.

    1995-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.

    2006-01-01

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

  17. Joint Polar Satellite System (JPSS) Common Ground System (CGS) Block 3.0 Communications Strategies

    NASA Astrophysics Data System (ADS)

    Miller, S. W.; Grant, K. D.; Ottinger, K.

    2015-12-01

    The National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation civilian weather and environmental satellite system: the Joint Polar Satellite System (JPSS). The JPSS program is the follow-on for both space and ground systems to the Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA. The JPSS satellites will carry a suite of sensors designed to collect meteorological, oceanographic, climatological and geophysical observations of the Earth. The ground processing system for JPSS is known as the JPSS Common Ground System (JPSS CGS). Developed and maintained by Raytheon Intelligence, Information and Services (IIS), the CGS is a globally distributed, multi-mission system serving NOAA, NASA and their national and international partners. The CGS has demonstrated its scalability and flexibility to incorporate multiple missions efficiently and with minimal cost, schedule and risk, while strengthening global partnerships in weather and environmental monitoring. In a highly successful international partnership between NOAA and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), the CGS currently provides data routing from McMurdo Station in Antarctica to the EUMETSAT processing center in Darmstadt, Germany. Continuing and building upon that partnership, NOAA and EUMETSAT are collaborating on the development of a new path forward for the 2020's. One approach being explored is a concept of operations where each organization shares satellite downlink resources with the other. This paper will describe that approach, as well as modeling results that demonstrate its feasibility and expected performance.

  18. Two-tone intermodulation analysis of communication satellite transponders

    NASA Technical Reports Server (NTRS)

    Riddle, L. P.

    1985-01-01

    Amplitudes of the in-band intermodulation products that arise when two equal-amplitude sinusoids are transmitted through a satellite transponder can be found from a linear transformation when the transponder characteristic is represented by a polynomial. Conversely, the nonlinearity that produces the intermodulation levels measured in a two-tone test can be found from the inverse transformation. As an application, the bandpass nonlinearity is deduced that gives rise to two-tone IM amplitudes that were measured during orbital tests of a satellite transponder, and compared with the measured bandpass characteristic.

  19. Communication satellite ground station receiver performance at low data rates

    NASA Astrophysics Data System (ADS)

    Riddle, L. P.

    Performance of satellite ground station receivers at low data rates is analyzed for power-limited satellites, when various amounts of frequency dynamics are present. Specifically, the lowest data rates for which the receiver can successfully demodulate suppressed-carrier BPSK data under a wide variety of conditions are determined. Minimum data rates on the order of 100 to 1400 bits per second are achievable with a bit error probability less than 0.00001 and with a mean time to cycle slip on the order of 1/2 hour or more, when Costas loops are employed for carrier extraction.

  20. Communication satellite ground station receiver performance at low data rates

    NASA Technical Reports Server (NTRS)

    Riddle, L. P.

    1982-01-01

    Performance of satellite ground station receivers at low data rates is analyzed for power-limited satellites, when various amounts of frequency dynamics are present. Specifically, the lowest data rates for which the receiver can successfully demodulate suppressed-carrier BPSK data under a wide variety of conditions are determined. Minimum data rates on the order of 100 to 1400 bits per second are achievable with a bit error probability less than 0.00001 and with a mean time to cycle slip on the order of 1/2 hour or more, when Costas loops are employed for carrier extraction.