Sample records for radio satellite corporation

  1. Amateur Radio Satellite Communications.

    ERIC Educational Resources Information Center

    Koch, David P.

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

  2. Satellite Imaging Corporation: IKONOS Satellite Images

    NSDL National Science Digital Library

    Satellite Imaging Corporation

    Satellite Imaging Corporation (SIC) acquires and processes imagery from the IKONOS satellite as well as others and makes the products available through their website. The images in the gallery are arranged in several categories based on what applications the images might be useful for, such as Agriculture, Coastal Management, or Sports and Tourism.

  3. Direct Broadcast Satellite: Radio Program

    NASA Technical Reports Server (NTRS)

    Hollansworth, James E.

    1992-01-01

    NASA is committed to providing technology development that leads to the introduction of new commercial applications for communications satellites. The Direct Broadcast Satellite-Radio (DBS-R) Program is a joint effort between The National Aeronautics and Space Administration (NASA) and The United States Information Agency/Voice of America (USIA/VOA) directed at this objective. The purpose of this program is to define the service and develop the technology for a direct-to-listener satellite sound broadcasting system. The DBS-R Program, as structured by NASA and VOA, is now a three-phase program designed to help the U.S. commercial communications satellite and receiver industry bring about this new communications service. Major efforts are being directed towards frequency planning hardware and service development, service demonstration, and experimentation with new satellite and receiver technology.

  4. The Aerospace Corporation 2009 Communication Satellite Systems

    E-print Network

    Low, Steven H.

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

  5. Geostar Radio Determination Satellite System

    NASA Astrophysics Data System (ADS)

    Richards, Robert T.

    The Geostar Radio Determination Satellite System is designed to provide accurate position information and ancillary message passing capability for land mobile, marine, and aeronautical users in the United States and eventually worldwide. The Geostar system is a random access spread spectrum system capable of high positioning accuracy. Geostar can support a large population of users operating inexpensive transceivers. This paper examines the Geostar system positioning technique, error sources, anticipated accuracy, and potential applications.

  6. Satellite radio beacon monitoring of the troposphere

    Microsoft Academic Search

    Y. V. Somayajulu; T. R. Tyagi; A. B. Ghosh

    1975-01-01

    In this communication some effects of characteristic enhancements and\\/or fluctuations of the satellite radio beacon transmissions are described. It is convincingly shown that these effects are of tropospheric origin. The satellite radio beacon can thus be used for monitoring the tropospheric events.

  7. Corporate strategies for satellite communications

    NASA Astrophysics Data System (ADS)

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

    1991-10-01

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

  8. The 'Geostar' radio determination satellite system

    NASA Astrophysics Data System (ADS)

    Oneill, G. K.

    1986-05-01

    The proposed Geostar system which links portable and mobile terminals directly through satellite relays to a ground-based computer is capable of providing the following services in a variety of transportation modes: (1) navigational positioning, (2) terrain warning to pilots and hazard warning to mariners, (3) approach guidance for aircraft and (4) two-way digital message service. Able to operate in a supplementary or advisory mode, the Geostar system combines the existing technologies of orbital satellites, computers and integrated circuits. It consists of the following: (1) a ground station with a computer, two or more satellites at fixed locations in earth orbit, and terminals carried by aircraft, surface vehicles, etc. Geostar's practical implications are discussed as well as the fitting of its necessary radio frequencies in the ITU table of allocations.

  9. Direct broadcast satellite-radio, receiver development

    NASA Technical Reports Server (NTRS)

    Vaisnys, A.; Bell, D.; Gevargiz, J.; Golshan, Nasser

    1993-01-01

    The status of the ongoing Direct Broadcast Satellite-Radio (DBS-R) Receiver Development Task being performed at the Jet Propulsion Laboratory, California Institute of Technology (JPL) is reported. This work is sponsored by the Voice of America/U.S. Information Agency through an agreement with NASA. The objective of this task is to develop, build, test, and demonstrate a prototype receiver that is compatible with reception of digital audio programs broadcast via satellites. The receiver is being designed to operate under a range of reception conditions, including fixed, portable, and mobile, as well as over a sufficiently wide range of bit rates to accommodate broadcasting systems with different cost/audio quality objectives. While the requirements on the receiver are complex, the eventual goal of the design effort is to make the design compatible with low cost production as a consumer product. One solution may be a basic low cost core design suitable for a majority of reception conditions, with optional enhancements for reception in especially difficult environments. Some of the receiver design parameters were established through analysis, laboratory tests, and a prototype satellite experiment accomplished in late 1991. Many of the necessary design trades will be made during the current simulation effort, while a few of the key design options will be incorporated into the prototype for evaluation during the planned satellite field trials.

  10. APPLICATION OF SMALL SATELLITES FOR HIGH PRECISION MEASURING EFFECTS OF RADIO WAVE PROPAGATION

    Microsoft Academic Search

    K. Igarashi; N. A. Armand; A. G. Pavelyev; Ch. Reigber; J. Wickert; K. Hocke; G. Beyerle; S. S. Matyugov; O. I. Yakovlev

    The radio holography methodology may be applied in the scientific programs for future small satellite that will use radio signals emitted by radio navigation, radio communication satellites for precise measuring effects of radio waves propagation at low elevation angles and for global monitoring of radio communication channels passed through the atmosphere and ionosphere. Another task consists in monitoring of the

  11. Wave propagation and earth satellite radio emission studies

    NASA Technical Reports Server (NTRS)

    Yeh, K. C.; Liu, C. H.; Flaherty, B. J.

    1974-01-01

    Radio propagation studies of the ionosphere using satellite radio beacons are described. The ionosphere is known as a dispersive, inhomogeneous, irregular and sometimes even nonlinear medium. After traversing through the ionosphere the radio signal bears signatures of these characteristics. A study of these signatures will be helpful in two areas: (1) It will assist in learning the behavior of the medium, in this case the ionosphere. (2) It will provide information of the kind of signal characteristics and statistics to be expected for communication and navigational satellite systems that use the similar geometry.

  12. Satellite emission radio interferometric earth surveying series - GPS geodetic system

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.

    1979-01-01

    A concept called SERIES (satellite emissions radio interferometric earth surveying) which makes use of GPS (global positioning system) radio transmissions without any satellite modifications, is described. Through the use of very long baseline interferometry (VLBI) and its calibration methods, 0.5 to 3 cm three dimensional baseline accuracy can be achieved over distances of 2 to 200 km respectively, with only 2 hours of on-site data acquisition. Attention is given to such areas as: the radio flux equivalent of GPS transmissions, synthesized delay precision, transmission and frequency subsystem requirements, tropospheric and ionospheric errors. Applications covered include geodesy and seismic tectonics.

  13. Radio and television broadcasting by satellite

    Microsoft Academic Search

    C. Rosetti

    1980-01-01

    Direct broadcasting of television and radio from space transmitters in geostationary orbit is close to realisation. This article discusses the implications and technical problems of such communications systems

  14. ATMOSPHERIC REMOTE SENSING USING SPACE-BASED RADIO NAVIGATION SATELLITES

    Microsoft Academic Search

    SAMSUNG LIM; CHRIS RIZOS

    Given that agricultural cycles, human well-being, economic growth and many societal activities are affected by climate variability, a greater understanding of critical atmospheric parameters (such as refractivity, pressure, temperature and humidity) is of paramount importance. Recently many countries have investigated the feasibility of using the space-based radio navigation satellites of the Global Positioning System (GPS) for weather and environmental studies.

  15. The problem of spiral galaxies and satellite radio sources

    NASA Technical Reports Server (NTRS)

    Arp, H.; Carpenter, R.; Gulkis, S.; Klein, M.

    1976-01-01

    Regions 2-deg x 2-deg in area centered on four spiral galaxies were scanned with the Goldstone 64-m antenna in search of satellite radio sources at 2295 MHz. Four control regions of equal area but free of galaxies brighter than 13th magnitude were also scanned. No significant excess in the number density of sources with flux densities greater than 0.10 Jy relative to the control fields was found. A detailed comparison is made between the results of this program and the results of previous investigators. In particular, attention is directed to the potentially important implications of an investigation by Tovmasyan (1968), who searched a large number of spirals and found evidence that a small percentage of them apparently have radio satellites located up to 20 arcmin from the central galaxy. Fifteen sources selected from Tovmasyan's list of 43 satellite sources were measured. The present results confirm his positions and relative flux densities for each of the sources.

  16. Improved Radio Emissivities for Satellites of Saturn

    NASA Astrophysics Data System (ADS)

    Ries, Paul

    2010-10-01

    The size distribution of TNOs is one of the most important constraints on the history of the early solar system. However, while TNOs are most detectable in the visible and near-IR wavelengths, their albedos vary substantially, thus creating uncertainty in their sizes when determined from reflected light alone. One way of determining the size distribution for a large number of TNOs is to measure their thermal emission, such as has been done with Spitzer and Herschel. However, in just a few year's time, ALMA will be coming online, and will be able to detect thermal emission from even more TNOs. However, thermal emission from Solar System bodies in the millimeter and submillimeter, such as that which ALMA will detect, is not that of a pure blackbody. Pluto, the Gallillean satellites, and Vesta have all shown deviations from unity emissivity. However, the cause of this variation is not well understood. Here we re-analayze data from the Cassini RADAR instrument at 2.5 cm. Cassini RADAR measured the brightness temperature and emissivity of several of Saturn's icy satellites, at least one of which, Phoebe, is thought to be a captured TNO. Previous emissivity determinations relied on relatively simple thermal models. We recalculate emissivities using thermal models based on recent data obtained with the CIRS (infrared) instrument on Cassini which account for, among other things, diurnal effects and the rotation during the RADAR observations. For one important result, we demonstrate that deviation from unity emissivity on Iapetus is due solely to surface depth effects at long wavelengths when RADAR data at 2.5 cm is combined with data obtained at 3.3 mm on the Green Bank Telescope (GBT). This research is supported by a grant under the NRAO Student Observing Support program.

  17. Fade durations in satellite-path mobile radio propagation

    NASA Astrophysics Data System (ADS)

    Schmier, Robert G.; Bostian, Charles W.

    1986-12-01

    Fades on satellite to land mobile radio links are caused by several factors, the most important of which are multipath propagation and vegetative shadowing. Designers of vehicular satellite communications systems require information about the statistics of fade durations in order to overcome or compensate for the fades. Except for a few limiting cases, only the mean fade duration can be determined analytically, and all other statistics must be obtained experimentally or via simulation. This report describes and presents results from a computer program developed at Virginia Tech to simulate satellite path propagation of a mobile station in a rural area. It generates rapidly-fading and slowly-fading signals by separate processes that yield correct cumulative signal distributions and then combines these to simulate the overall signal. This is then analyzed to yield the statistics of fade duration.

  18. Fade durations in satellite-path mobile radio propagation

    NASA Technical Reports Server (NTRS)

    Schmier, Robert G.; Bostian, Charles W.

    1986-01-01

    Fades on satellite to land mobile radio links are caused by several factors, the most important of which are multipath propagation and vegetative shadowing. Designers of vehicular satellite communications systems require information about the statistics of fade durations in order to overcome or compensate for the fades. Except for a few limiting cases, only the mean fade duration can be determined analytically, and all other statistics must be obtained experimentally or via simulation. This report describes and presents results from a computer program developed at Virginia Tech to simulate satellite path propagation of a mobile station in a rural area. It generates rapidly-fading and slowly-fading signals by separate processes that yield correct cumulative signal distributions and then combines these to simulate the overall signal. This is then analyzed to yield the statistics of fade duration.

  19. ATS6-satellite radio beacon measurements at Ootacamund, India

    NASA Technical Reports Server (NTRS)

    Davies, K.; Donnelly, R. F.; Grubb, R. N.; Rama Rao, P. V. S.; Rastogi, R. G.; Deshpande, M. R.; Chandra, H.; Vats, H. O.; Sethia, G.

    1978-01-01

    In August 1975 the ATS6 was repositioned at 35 deg E. Radio beacon measurements of time delay, Faraday rotation and signal amplitude, made at Ootacamund, India in October 1975, are discussed with emphasis on the problem of determining the Faraday content under essentially transverse propagation conditions. It is shown that at the low geomagnetic latitude of Ootacamund the use of a fixed conversion coefficient gives an unreliable Faraday content. It is shown also that corrections to the measured Faraday rotation are important because of pitch and yaw of the satellite, particularly at night when the rotation on 140 MHz can be of the order of 10 to 20 deg. The shape factor shows a low predawn minimum indicating the nearly complete erosion of the F2 layer peak. Amplitude scintillation usually decreases with increase of radio frequency but exceptions are discussed.

  20. Integrated Satellite Apt And Weather Radio Broadcast Processor

    NASA Astrophysics Data System (ADS)

    Ruggles, Kenneth W.

    1988-01-01

    This paper describes a microcomputer-based system to simultaneously receive, process and display satellite APT cloud images, satellite APT cloud/sea surface temperature fields, weather broadcast teleprinter messages and weather broadcast facsimile charts. While performing other processing, the system can drive a facsimile recorder, a graphics printer or a landline/radio facsimile broadcast. This semi-portable and affordable system was specifically designed for use by remote users of weather data such as fishing vessels, merchant ships, smaller detached weather service centers/offices and field military units etc. The heart of the system is a unique Data Manager Card and a low-cost, high resolution image display supporting up to 64 grey shades and/or high resolution color. The paper outlines plans to conduct an at-sea evaluation of the system this winter aboard an American tuna clipper operating in the western South Pacific Ocean.

  1. Time transfer via satellite-link radio interferometry

    NASA Technical Reports Server (NTRS)

    Knowles, S. H.; Waltman, W. B.; Yen, J. L.; Cannon, W. H.; Petrachenko, W. T.; Broten, N. W.; Costain, C.; Fort, D. H.; Galt, J. A.; Popelar, J.

    1979-01-01

    Very long baseline interferometry using natural radio sources was investigated as a possible time transfer method. Antennas were linked using a synchronous communications satellite instead of the customary independent frequency standards and tape recorders. A successful preliminary time transfer was performed using a wideband data link that was accurate at the 100 nanosecond level, and frequency standards were compared to a part in 10 to the minus thirteenth power over a 24 hour period using a phase coherent satellite link. The narrow band phase coherent link method is potentially capable of timing accuracy of 10 picoseconds, and frequency comparison accuracy of 10 to the minus sixteenth power, and is in addition economical of spectrum usage.

  2. Utilizing a TDRS satellite for direct broadcast satellite-radio propagation experiments and demonstrations

    NASA Technical Reports Server (NTRS)

    Hollansworth, James E.

    1993-01-01

    The NASA/VOA Direct Broadcast Satellite - Radio (DBS-R) Program will be using a NASA Tracking Data Relay Satellite (TDRS) satellite at 62 deg West longitude to conduct live satellite S-band propagation experiments and demonstrations of satellite sound broadcasting over the next two years (1993-1994). The NASA/VOA DBS-R program has applied intensive effort to garner domestic and international support for the DBS-R concept. An S-band DBS-R allocation was achieved for Region 2 at WARC-92 held in Spain. With this allocation, the DBS-R program now needs to conduct S-band propagation experiments and systems demonstrations that will assist in the development of planning approaches for the use of Broadcast Satellite Service (Sound) frequency bands prior to the planning conference called for by WARC-92. These activities will also support receiver concept development applied to qualities ranging from AM to Monophonic FM, Stereophonic FM, Monophonic CD, and Stereophonic CD quality.

  3. Utilizing a TDRS satellite for direct broadcast satellite-radio propagation experiments and demonstrations

    NASA Technical Reports Server (NTRS)

    Hollansworth, James E.

    1993-01-01

    The NASA/VOA Direct Broadcast Satellite - Radio (DBS-R) Program will be using a NASA Tracking Data Relay Satellite (TDRS) at 62 deg West longitude to conduct live satellite S-band propagation experiments and demonstrations of satellite sound broadcasting over the next two years (1993-1994). The NASA/VOA DBS-R program has applied intensive effort to garner domestic and international support for the DBS-R concept. An S-band DBS-R allocation was achieved for Region 2 at WARC-92 held in Spain. With this allocation, the DBS-R program now needs to conduct S-band propagation experiments and systems demonstrations that will assist in the development of planning approaches for the use of Broadcast Satellite Service (Sound) frequency bands prior to the planning conference called for by WARC-92. These activities will also support receiver concept development applied to qualities ranging from AM to Monophonic FM, Stereophonic FM, Monophonic CD, and Stereophonic CD quality.

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

    ERIC Educational Resources Information Center

    Lee, William E.

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

  5. Improved radio tomography of the ionosphere using EUV\\/optical measurements from satellites

    Microsoft Academic Search

    P. A. Bernhardt; K. F. Dymond; J. M. Picone; D. M. Cotton; S. Chakrabarti; T. A. Cook; J. S. Vickers

    1997-01-01

    Computerized tomography of the ionosphere employs radio beacons on satellites and ground-based receivers that measure the integrated electron densities along line-of-sight propagation paths. The primary limitation to satellite-based ionospheric radio tomography is the lack of near-horizontal ray paths. This restricts the accuracy for the reconstruction of vertical profiles in the F region. Horizontal integration paths may be obtained using the

  6. The Last Millimeter: Interfacing the New Public Radio Satellite System. Info. Packets No. 14.

    ERIC Educational Resources Information Center

    Pizzi, Skip

    Public radio is about to achieve a new technological level as the new Public Radio Satellite System (PRSS) is deployed. The network will dramatically improve the capacity and quality of its interconnection system, but proper interfacing at member stations will be required to realize the full benefits of the new system. The new system uses digital…

  7. OLFAR a radio telescope based on nano satellites in moon orbit

    Microsoft Academic Search

    S. Engelen; C. J. M. Verhoeven; M. J. Bentum

    2010-01-01

    It seems very likely that missions with nano-satellites in professional scientific or commercial applications will not be single-satellite missions. Well structured formations or less structured swarms of nano-satellites will be able to perform tasks that cannot be done in the “traditional” way. The Dutch space-born radio telescope project OLFAR, the Orbiting Low Frequency Array, is a good example of a

  8. Communications via the radio artificial earth satellite: Design of the tracking diagram and features for conducting QSO

    NASA Technical Reports Server (NTRS)

    Dobrozhanskiy, V.; Rybkin, V.

    1980-01-01

    A detailed examination is made of the operation of a transmitting artifical Earth satellite. A tracking diagram for the satellite is constructed. The zone of radio visibility can be determined based on the techniques proposed.

  9. Frequency-hop transmission for satellite packet switching and terrestrial packet radio networks

    Microsoft Academic Search

    Michael B. Pursley

    1986-01-01

    The performance frequency-hop transmission in a packet communication network is analyzed. Satellite multiple-access broadcast channels for packet switching and terrestrial packet radio networks are the primary examples of the type of network considered. An analysis of the effects of multiple-access interference in frequency-hop radio networks is presented. New measures of 'local' performance are defined and evaluated for networks of this

  10. Copyright 2004, Intel Corporation, All rights reserved. Place Lab: Device Positioning Using Radio Beacons in the Wild

    E-print Network

    Chawathe, Yatin

    Copyright 2004, Intel Corporation, All rights reserved. Place Lab: Device Positioning Using Radio DISCLAIM ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PROPRIETARY RIGHTS, RELATING TO USE;Place Lab: Device Positioning Using Radio Beacons in the Wild Anthony LaMarca1 , Yatin Chawathe1 , Sunny

  11. The radio astronomy explorer satellite, a low-frequency observatory.

    NASA Technical Reports Server (NTRS)

    Weber, R. R.; Alexander, J. K.; Stone, R. G.

    1971-01-01

    The RAE-1 is the first spacecraft designed exclusively for radio astronomical studies. It is a small, but relatively complex, observatory including two 229-meter antennas, several radiometer systems covering a frequency range of 0.2 to 9.2 MHz, and a variety of supporting experiments such as antenna impedance probes and TV cameras to monitor antenna shape. Since its launch in July, 1968, RAE-1 has sent back some 10 billion data bits per year on measurements of long-wavelength radio phenomena in the magnetosphere, the solar corona, and the Galaxy. In this paper we describe the design, calibration, and performance of the RAE-1 experiments in detail.

  12. The ionosphere, radio navigation, and global navigation satellite systems

    Microsoft Academic Search

    Paul M. Kintner; Brent M. Ledvina

    2005-01-01

    This article is a review of Global Navigation Satellite Systems (GNSS) for space scientists who are interested in how GNSS signals and observables can be used to understand ionospheric dynamics and, conversely, how ionospheric dynamics affect the operational capabilities of GNSS receivers. The most common form of GNSS is the Global Positioning System (GPS); we will first review its operating

  13. Channel and Traffic based Adaptive Radio Resource Management strategies for the return link of Ka\\/Q\\/V band Communication Satellite systems employing Fade Mitigation Techniques

    Microsoft Academic Search

    A. Aroumont; J. Radzik; M. Bousquet; L. Castanet

    2007-01-01

    Efficient utilization of the satellite radio resource is of paramount importance to a satellite system's performance and economic competitiveness. The likely use of Ka band and above frequencies for future satellite systems and the need for a better quality of service (QoS) complicate the radio resource management process especially in the return link of a satellite system, one that connects

  14. Using a Satellite Swarm for building a Space-based Radio Telescope for Low Frequencies

    NASA Astrophysics Data System (ADS)

    Bentum, Mark; Boonstra, A. J.; Verhoeven, C. J. M.; van der Veen, A. J.; Gill, E. K. A.; Saks, N.; Falcke, H.; Klein-Wolt, M.; Rajan, R. T.; Wijnholds, S. J.; Arts, M.; van't Klooster, K.; Beliün, F.; Meijerink, A.; Monna, B.; Rotteveel, J.; Boer, M. A.; Bongers, E.; Boom, E.; van Tuijl, E.; van Staveren, A.

    In radio astronomy, as in astronomy in general, a wide range of frequencies is observed as each spectral band offers a unique window to study astrophysical phenomena. In the recent years, new observatories have been designed and built at the extreme limits of the radio spectrum. For the low frequencies several Earth-based radio telescopes are constructed at this moment. In the Netherlands, the Low Frequency Array (LOFAR) is being constructed at this moment and will be operational later this year. LOFAR observes the sky between 30 and 240 MHz. Observing at even lower frequencies is very interesting, but, due to the influence of the Earth's ionosphere this is not possible from Earth. Thus, the only option to observe low frequencies is a telescope in space. In the past several studies have been conducted on a low-frequency space-based radio tele-scope. In the recent ESA project Distributed Aperture Array for Radio Astronomy in Space (DARIS), such a mission was studied in detail. The study focused on a moderate-size three-dimensional satellite constellation operating as a coherent large-aperture synthesis array. The DARIS project is presented in a separate conference contribution. In the DARIS project the focus was on technology available at this moment, with an outlook and technological development plan/roadmap to be exploited for the future. Using current-day technologies, a space-based low-frequency array would be bulky and, thus, costly. A logical next step would be to investigate possibilities to miniaturize the electronics and use very small satellites, perhaps even nano satellites with masses between 1-10 kg to build the radio tele-scope. The approach is to use a swarm of satellites to establish a virtual telescope to perform the astronomical task. This is investigated in the NWO/STW-funded OLFAR (Orbiting Low Frequency Array) project. The OLFAR radio telescope will be composed of an antenna array based on satellites deployed at a location where the Earth's interference is limited, and where the satellites can be maintained in a three-dimensional configuration with a maximum diameter of 100 km. A Moon orbit could be suitable option. Each individual satellite will consist of deployable antennas. The sky signals will be amplified using an integrated ultra-low power direct sampling receiver and digitizer. Using digital fil-tering, any subband within the LNA passband can be selected. The data will be distributed over the available nodes in space. On-board signal processing will filter the data, invoke RFI mitigation algorithms (if necessary), and finally, correlate the data in a phased array mode. If more satellites are available, they will automatically join the array. The final correlated or beam-formed data will be sent to Earth as part of the telemetry data using a radio link. As the satellites will be far away from Earth, communication to and from Earth will require diversity communication schemes, using all the individual satellites together. In this paper, the design parameters for the satellites and the swarm will be discussed and status of the OLFAR project will be reported. Details will be given about the system and the signals that are expected.

  15. Femto-Satellite system for radio-occultation study of the Ionosphere

    NASA Astrophysics Data System (ADS)

    Savio Bradford, Brandon; Gutierrez Cabello, Jordi

    This research project proposes the use of (a swarm of) Femto-Satellites in the study of Ionospheric properties using \\underline{Radio-Occultation} techniques. It makes use of GPS signals, a computing system, tiny on-board components and a data transfer module. This project is being done as a cheaper and lightweight alternative proposal to the higher cost, already running COSMIC program and other programs which use larger satellites to perform Radio-Occultation study of the Ionosphere. Being that these femto-satellites are capable of acting as a constellation, they will be able to provide higher accuracy radio-occultation readings of the Ionosphere due to the close proximity between each satellite positioned in low earth orbit. Important parameters attempted for this system include a weight of 100 grams per satellite system and an innovative power source using solar sails. The sails also serve to provide an anti-debris system of redundancy to make sure these tiny satellites don't add to the already alarming amount of space debris, in the event of a malfunction. Ultimately, having a large amount of tiny satellites serving to study the ionosphere at closer proximities and obtain more accurate results will give the scientific community a better understanding of the constant changes in the space environment at a given altitude. This could help humanity combat adverse changes in climate, which heavily affects some regions of agriculture. This could also help advance the scientific campaign against global warming, by providing real-time readings from different regions of the ionosphere.

  16. Satellite observations of type 3 solar radio bursts at low frequencies

    NASA Technical Reports Server (NTRS)

    Fainberg, J.; Stone, R. G.

    1973-01-01

    Type III solar radio bursts were observed from 10 MHz to 10 KHz by satellite experiments above the terrestrial plasmasphere. Solar radio emission in this frequency range results from excitation of the interplanetary plasma by energetic particles propagating outward along open field lines over distances from 5 solar radii to at least 1 AU from the sun. This review summarizes the morphology, characteristics and analysis of individual as well as storms of bursts. Burst rise times are interpreted in terms of exciter length and dispersion while decay times refer to the radiation damping process. The combination of radio observations at the lower frequencies and in-situ measurements on nonrelativistic electrons at 1 AU provide data on the energy range and efficiency of the wave-particle interactions responsible for the radio emission.

  17. Radio sky mapping from satellites at very low frequencies

    NASA Technical Reports Server (NTRS)

    Storey, L. R. O.

    1991-01-01

    Wave Distribution Function (WDF) analysis is a procedure for making sky maps of the sources of natural electromagnetic waves in space plasmas, given local measurements of some or all of the three magnetic and three electric field components. The work that still needs to be done on this subject includes solving basic methodological problems, translating the solution into efficient algorithms, and embodying the algorithms in computer software. One important scientific use of WDF analysis is to identify the mode of origin of plasmaspheric hiss. Some of the data from the Japanese satellite Akebono (EXOS D) are likely to be suitable for this purpose.

  18. Broadcasting of radio programmes by satellite direct to portable/vehicle receivers

    NASA Astrophysics Data System (ADS)

    Chaplin, J.; Fromm, H.-H.; Rosetti, C.

    1984-02-01

    The technical and economic feasibility of direct satellite broadcast of sound radio to portable receivers is evaluated, with a focus on coverage of rural areas in Africa. The need for improved coverage is indicated, and the cost of the terrestrial alternative (a network of solar-powered VHF/FM transmitters) is estimated as about one million dollars/year (spread over 10 yrs) for a country like kenya. The satellite system recommended uses the 0.5-2.0-GHz UHF band, a large satellite with a 10-m-diameter antenna and at least 100-W power (perhaps a multichannel satellite serving several countries or providing both direct-broadcast and trunk-communications functions), and portable or car receivers comprising a standard VHF/FM radio plus a UHF/VHF converter and a printed-Yagi or slot-dipole antenna. It is argued that the satellite system can be economically competitive with the terrestrial network and provide more reliable service. Allocation of orbital positions and frequencies for sond broadcasting is scheduled for consideration at the next WARC, ORB-85 in August 1985.

  19. Measurement of the gravitational redshift effect with RadioAstron satellite

    E-print Network

    A. V. Birukov; V. L. Kauts; D. A. Litvinov; N. K. Porayko; V. N. Rudenko

    2015-06-07

    RadioAstron satellite admits in principle a testing the gravitational redshift effect with an accuracy of better than $10^{-5}$. It would surpass the result of Gravity Probe A mission at least an order of magnitude. However, RadioAstron's communications and frequency transfer systems are not adapted for a direct application of the non relativistic Doppler and troposphere compensation scheme used in the Gravity Probe A experiment. This leads to degradation of the redshift test accuracy approximately to the level 0.01. We discuss the way to overcome this difficulty and present preliminary results based on data obtained during special observing sessions scheduled for testing the new techniques.

  20. Measurement of the gravitational redshift effect with RadioAstron satellite

    E-print Network

    Birukov, A V; Litvinov, D A; Porayko, N K; Rudenko, V N

    2015-01-01

    RadioAstron satellite admits in principle a testing the gravitational redshift effect with an accuracy of better than $10^{-5}$. It would surpass the result of Gravity Probe A mission at least an order of magnitude. However, RadioAstron's communications and frequency transfer systems are not adapted for a direct application of the non relativistic Doppler and troposphere compensation scheme used in the Gravity Probe A experiment. This leads to degradation of the redshift test accuracy approximately to the level 0.01. We discuss the way to overcome this difficulty and present preliminary results based on data obtained during special observing sessions scheduled for testing the new techniques.

  1. ATS-6 satellite radio beacon measurements at Ootacamund, India

    NASA Technical Reports Server (NTRS)

    Davies, K.; Donnelly, R. F.; Grubb, R. N.; Rao, P. V. S. R.; Rastogi, R. G.; Deshpande, M. R.; Chandra, H.; Vats, H. O.; Sethia, G.

    1979-01-01

    ATS-6 radio beacon measurements of modulation phase and Faraday rotation made at Ootacamund, India in 1975-1976 are discussed with emphasis on the measurement and analysis errors. The modulation-phase errors are insensitive to the geomagnetic field and provide an accurate determination of the total columnar electron content. Comparison of modulation-phase measurements at different frequencies shows a minor sensitivity to the ATS-6 pitch angle. For the low geomagnetic latitude and nearly transverse propagation conditions of Ootacamund, the use of a fixed conversion coefficient gives an unreliable Faraday content. However, the Faraday rotation measurements may be used to determine the shape factor F, which provides information about the electron density height profile.

  2. Networked Operations of Hybrid Radio Optical Communications Satellites

    NASA Technical Reports Server (NTRS)

    Hylton, Alan; Raible, Daniel

    2014-01-01

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

  3. Propagation measurements for satellite radio reception inside buildings

    NASA Technical Reports Server (NTRS)

    Vogel, Wolfhard J.; Torrence, Geoffrey W.

    1993-01-01

    Swept CW signals (from 700 to 1800 MHz) were received inside six buildings of brick, corrugated sheet-metal, wood-frame, mobile-home, and reinforced concrete-wall construction. A transmitter antenna was mounted outdoors on top of an 18 m tower to simulate a satellite, and a linearly scanned directional receiver antenna was used to probe the spatial, spectral, and temporal variability of the signal indoors. Levels were found to have much structure in the spatial and frequency domain, but were relatively stable in time. Typically, people moving nearby produced variations of less than 0.5 dB, whereas a person blocking the transmission path produced fades of 6 to 10 dB. Severe losses (17.5 dB) were observed in the concrete-wall building, which also exhibited the longest multipath delays (over 100 ns). Losses inside a mobile home were even larger (over 20 dB) and were independent of antenna orientation. The power-frequency distortion increased with the logarithm of the bandwidth, but could be reduced by moving to a position of higher power. Only the losses showed a clear frequency dependence, but they could be mitigated by moving the antenna.

  4. Analysis of type 3 solar radio bursts observed at kilometric wavelengths from the OGO-5 satellite

    NASA Technical Reports Server (NTRS)

    Alvarez, H.

    1971-01-01

    Research was conducted to analyze the data on solar radio bursts obtained by the OGO-5 satellite. Since the wavelengths corresponding to the three lowest frequencies of observations exceeded one kilometer, the bursts detected in those channels were designated as kilometer-waves. The data search covered approximately 9200 hours between March 1968 and February 1970, and included the maximum of solar cycle No. 20. The study concentrated on 64 Type 3 solar radio events reaching frequencies equal or lower than 0.35 MHz. This selection criteria led to the choice of the most intense radio events. Measurements included: times of start, times of decay, and amplitudes of the 64 events. The consistency of the results, within the accuracy of the measurements, lends support to some of the assumptions made for the analysis, notably, the validity of the local plasma hypothesis, the constancy of the exciter particles velocity, and spiral shape of their trajectory.

  5. Digital Radio Broadcasting using the mixed satellite/terrestrial approach: An application study

    NASA Technical Reports Server (NTRS)

    Paiement, Richard V.; Voyer, Rene; Prendergast, Doug

    1995-01-01

    Digital radio broadcasting (DRB) is a new service that offers CD quality stereo programs to fixed, portable and mobile receivers. Terrestrial DRB in Canada is considered as a replacement technology for existing AM and FM services, and it is expected to start up in 1996. Canada currently favors Eureka 147 technology operating in the L-band, in the 1452-1492 MHz frequency band allocated during WARC'92 for DRB. Terrestrial DRB delivery is appropriate for small to medium sized service areas, such as cities and their associated suburbs. For larger areas such as provinces, as well as for sparsely populated areas such as the regions in northern Canada, satellite delivery is more appropriate. The mixed approach is based on both satellite and terrestrial broadcasting services using a common frequency band. Spectrum efficiency is achieved through close coordination of both service types, to achieve proper frequency sharing and spectrum re-use. As well, use of a common transmission format by both types of services allows for a common receiver. This mixed satellite/terrestrial approach to DRB is being seriously considered in Canada and in other countries. This paper studies the feasibility of such a mixed satellite/terrestrial DRB system. It looks at possible coverage scenarios for Canada, and at the satellite and receiver technology requirements.

  6. Recovery of refractivity profiles and pressure and temperature distributions in the lower atmosphere from satellite-to-satellite radio occultation data

    NASA Technical Reports Server (NTRS)

    Murray, C. W., Jr.

    1977-01-01

    The feasibility of recovering parameters from one-way range rate between two earth orbiting spacecraft during occultation of the tracking signal by the earth's lower atmosphere. The tracking data is inverted by an integral transformation (Abel transform) to obtain a vertical refractivity profile above the point of closest approach of the ray connecting the satellites. Pressure and temperature distributions can be obtained from values of dry refractivity using the hydrostatic equation and perfect gas law. Two methods are investigated for recovering pressure and temperature parameters. Results show that recovery is much more sensitive to satellite velocity errors than to satellite position errors. An error analysis is performed. An example is given demonstrating recovery of parameters from radio occultation data obtained during satellite-to-satellite tracking of Nimbus 6 by the ATS 6 satellite.

  7. Rural land mobile radio market assessment and satellite and terrestrial system concepts

    NASA Technical Reports Server (NTRS)

    Stevenson, S.; Provencher, C.

    1984-01-01

    The market for satellite-based mobile radio in the rural U.S. is evaluated, summarizing the results of two NASA-funded studies reported by Anderson et al. and Hornstein. The study aims are listed, and the results are presented in tables, graphs, and maps and discussed. Space systems are found to be competitive with land-based systems, providing superior service at lower subscriber charges, but having limited compatibility with urban cellular mobile-radio systems. Of the three system concepts evaluated from a technological standpoint (direct-to-mobile, mobile-translator, and hybrid), the mobile-translator concept is considered most cost effective, at least within the constraints assumed in the study.

  8. Adaptive sparse signal processing of satellite-based radio frequency (RF) recordings of lightning events

    NASA Astrophysics Data System (ADS)

    Moody, Daniela I.; Smith, David A.

    2014-05-01

    Ongoing research at Los Alamos National Laboratory studies the Earth's radio frequency (RF) background utilizing satellite-based RF observations of terrestrial lightning. Such impulsive events are dispersed through the ionosphere and appear as broadband nonlinear chirps at a receiver on-orbit. They occur in the presence of additive noise and structured clutter, making their classification challenging. The Fast On-orbit Recording of Transient Events (FORTE) satellite provided a rich RF lightning database. Application of modern pattern recognition techniques to this database may further lightning research in the scientific community, and potentially improve on-orbit processing and event discrimination capabilities for future satellite payloads. Conventional feature extraction techniques using analytical dictionaries, such as a short-time Fourier basis or wavelets, are not comprehensively suitable for analyzing the broadband RF pulses under consideration here. We explore an alternative approach based on non-analytical dictionaries learned directly from data, and extend two dictionary learning algorithms, K-SVD and Hebbian, for use with satellite RF data. Both algorithms allow us to learn features without relying on analytical constraints or additional knowledge about the expected signal characteristics. We then use a pursuit search over the learned dictionaries to generate sparse classification features, and discuss their performance in terms of event classification. We also use principal component analysis to analyze and compare the respective learned dictionary spaces to the real data space.

  9. Refractivity and temperature climate records from multiple radio occultation satellites consistent within 0.05%

    NASA Astrophysics Data System (ADS)

    Foelsche, U.; Scherllin-Pirscher, B.; Ladstädter, F.; Steiner, A. K.; Kirchengast, G.

    2011-09-01

    Data consistency is an important prerequisite to build radio occultation (RO) climatologies based on a combined record of data from different satellites. The presence of multiple RO receiving satellites in orbit over the same time period allows for testing this consistency. We used RO data from CHAMP (CHAllenging Minisatellite Payload for geoscientific research), six FORMOSAT-3/COSMIC satellites (Formosa Satellite Mission 3/Constellation Observing System for Meteorology, Ionosphere and Climate, F3C), and GRACE-A (Gravity Recovery and Climate Experiment). We show latitude-altitude-resolved results for an example month (October 2007) and the temporal evolution of differences in a climate record of global and monthly means from January 2007 to December 2009. Latitude- and altitude-resolved refractivity and dry temperature climatologies clearly show the influence of different sampling characteristics; monthly mean deviations from the multi-satellite mean over the altitude domain 10 km to 30 km typically reach 0.1% and 0.2 K, respectively. Nevertheless, the 3-yr average deviations (shorter for CHAMP) are less than 0.03% and 0.05 K, respectively. We find no indications for instrument degradation, temporal inhomogeneities in the RO records, or temporal trends in sampling patterns. Based on analysis fields from ECMWF (European Centre for Medium-Range Weather Forecasts), we can estimate - and subtract - the sampling error from each monthly climatology. After such subtraction, refractivity deviations are found reduced to <0.05% in almost any month and dry temperature deviations to <0.05 K (<0.02% relative) for almost every satellite and month. 3-yr average deviations are even reduced to <0.01% and <0.01 K (CHAMP: -0.05 K), respectively, establishing an amazing consistency of RO climatologies from different satellites. If applying the same processing scheme for all data, refractivity and dry temperature records from individual satellites with similar bending angle noise can be safely combined up to 30 km altitude (refractivity also up to 35 km) to a consistent single climate record of substantial value for climate monitoring in the upper troposphere and lower stratosphere.

  10. Numerical arc segmentation algorithm for a radio conference: A software tool for communication satellite systems planning

    NASA Technical Reports Server (NTRS)

    Whyte, W. A.; Heyward, A. O.; Ponchak, D. S.; Spence, R. L.; Zuzek, J. E.

    1988-01-01

    The Numerical Arc Segmentation Algorithm for a Radio Conference (NASARC) provides a method of generating predetermined arc segments for use in the development of an allotment planning procedure to be carried out at the 1988 World Administrative Radio Conference (WARC) on the Use of the Geostationary Satellite Orbit and the Planning of Space Services Utilizing It. Through careful selection of the predetermined arc (PDA) for each administration, flexibility can be increased in terms of choice of system technical characteristics and specific orbit location while reducing the need for coordination among administrations. The NASARC software determines pairwise compatibility between all possible service areas at discrete arc locations. NASARC then exhaustively enumerates groups of administrations whose satellites can be closely located in orbit, and finds the arc segment over which each such compatible group exists. From the set of all possible compatible groupings, groups and their associated arc segments are selected using a heuristic procedure such that a PDA is identified for each administration. Various aspects of the NASARC concept and how the software accomplishes specific features of allotment planning are discussed.

  11. Airborne Remote Observations of L-Band Radio Frequency Interference and Implications for Satellite Missions

    NASA Technical Reports Server (NTRS)

    Laymon, Charles; Srinivasan, Karthik; Limaye, Ashutosh

    2011-01-01

    Passive remote sensing of the Earth s surface and atmosphere from space has significant importance in operational and research environmental studies, in particular for the scientific understanding, monitoring and prediction of climate change and its impacts. Passive remote sensing requires the measurement of naturally occurring radiations, usually of very low power levels, which contain essential information on the physical process under investigation. As such, these sensed radio frequency bands are a unique natural resource enabling space borne passive sensing of the atmosphere and the Earth s surface that deserves adequate allocation to the Earth Exploration Satellite Service and absolute protection from interference. Unfortunately, radio frequency interference (RFI) is an increasing problem for Earth remote sensing, particularly for passive observations of natural emissions. Because these natural signals tend to be very weak, even low levels of interference received by a passive sensor may degrade the fidelity of scientific data. The characteristics of RFI (low-level interference and radar-pulse noise) are not well known because there has been no systematic surveillance, spectrum inventory or mapping of RFI. While conducting a flight experiment over central Tennessee in May 2010, RFI, a concern for any instrument operating in the passive L band frequency, was observed across 16 subbands between 1402-1427 MHz. Such a survey provides rare characterization data from which to further develop mitigation technologies as well as to identify bandwidths to avoid in future sensor formulation.

  12. Protection of passive radio frequencies used for earth exploration by satellite

    NASA Astrophysics Data System (ADS)

    Rochard, Guy

    2004-10-01

    Space-borne passive sensing of the Earth"s surface and atmosphere has an essential and increasing importance in Earth Observation. The impressive progress recently made or shortly expected in weather analysis, warning and forecasts (in particular for dangerous weather phenomena as rain and floods, storms, cyclones, droughts) as well as in the study and prediction of climate change, is mainly attributable to the spaceborne observations. On this basis, economic studies show that meteorological services have a high positive impact on a wide range of economic activities, notwithstanding safety of life and property aspects. Space-borne passive sensing feeds crucial observational data to numerical weather predction models run on the most advanced super-computers that are operated by a few global forecasting centers. All meteorological and environmental satellite organizations operate these crucial remote-sensing missions as part of the GOS of the World Weather Watch and others... Spaceborne passive sensing for meterological applications is performed in frequency bands allocated to the Earth Exploration-Satellite Service. This is named "EESS passive" in the ITU-R Radio Regulations. The appropriate bands are uniquely determined by the physical properties (e.g. molecular resonance) of constituents of the atmosphere, and are therefore one of the unique natural resources (similarly to Radio Astronomy bands). Passive measurements at several frequencies in the microwave spectrum must be made simultaneously in order to extract the individual contribution of the geophysical parameter of interest. Bands below 100 GHz are of particular importance to provide an "all-weather" capability since many clouds are almost transparent at these frequencies. Along this line, the two first figures below about zenithal opacity describes respectively the atmosphere optical thickness due to water vapor and dry components in the frequency range 1 to 275 GHz and 275 GHz to 1000 GHz on which have been based the definition of most of the current allocations to EESS (passive) that are listed, as currently specified in ITU-R Rec. SA.515-3 summarized below. Interference criteria and performance criteria of passive sensors are indicated in ITU-R Rec(s) SA.1028-2 and 1029-2, respectively. A common summary of these two Rec(s) is also available below.

  13. Assimilation of global navigation satellite radio occultation observations in GRAPES: Operational implementation

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Xue, Jishan

    2014-12-01

    This paper presents the design of an observation operator for assimilation of global navigation satellite system (GNSS) radio occultation (RO) refractivity and the related operational implementation strategy in the global GRAPES variational data assimilation system. A preliminary assessment of the RO data assimilation effect is performed. The results show that the RO data are one of the most important observation types in GRAPES, as they have a significant positive impact on the analysis and forecast at all ranges, especially in the Southern Hemisphere and the global stratosphere where in-situ measurements are lacking. The GRAPES model error cannot be controlled in the Southern Hemisphere without RO data being assimilated. In addition, it is found that the RO data play a key role in the stable running of the GRAPES global assimilation and forecast system. Even in a relatively simple global data assimilation experiment, in which only the conventional and RO data are assimilated, the system is able to run for more than nine months without drift compared with NCEP analyses. The analysis skills in both the Northern and Southern Hemispheres are still relatively comparable even after nine-month integration, especially in the stratosphere where the number of conventional observations decreases and RO observations with a uniform global coverage dominate gradually.

  14. Using a Satellite Swarm for building a Space-based Radio Telescope for Low Frequencies

    Microsoft Academic Search

    Mark Bentum; A. J. Boonstra; C. J. M. Verhoeven; A. J. van der Veen; E. K. A. Gill; N. Saks; H. Falcke; M. Klein-Wolt; R. T. Rajan; S. J. Wijnholds; M. Arts; K. van't Klooster; F. Beliün; A. Meijerink; B. Monna; J. Rotteveel; M. A. Boer; E. Bongers; E. Boom; E. van Tuijl; A. van Staveren

    2010-01-01

    In radio astronomy, as in astronomy in general, a wide range of frequencies is observed as each spectral band offers a unique window to study astrophysical phenomena. In the recent years, new observatories have been designed and built at the extreme limits of the radio spectrum. For the low frequencies several Earth-based radio telescopes are constructed at this moment. In

  15. Natural radio emission of Jupiter as interferences for radar investigations of the icy satellites of Jupiter

    NASA Astrophysics Data System (ADS)

    Cecconi, B.; Hess, S.; Hérique, A.; Santovito, M. R.; Santos-Costa, D.; Zarka, P.; Alberti, G.; Blankenship, D.; Bougeret, J. L.; Bruzzone, L.; Kofman, W.

    2011-10-01

    Radar instruments are part of the core payload of the two Europa Jupiter System Mission (EJSM) spacecraft: NASA-led Jupiter Europa Orbiter (JEO) and ESA-led Jupiter Ganymede Orbiter (JGO). At this point of the project, several frequency bands are under study for radar, which ranges between 5MHz and 50MHz. Part of this frequency range overlaps with that of the natural Jovian radio emissions, which are very intense in the decametric range, below 40 MHz. Radio observations above 40 MHz are free of interferences, whereas below this threshold, careful observation strategies have to be investigated. We present a review of spectral intensity, variability and sources of these radio emissions. As the radio emission are strongly beamed, it is possible to model the visibility of the radio emissions, as seen from the vicinity of Europa or Ganymede. We have investigated Io-related radio emissions as well as radio emissions related to the auroral oval. We also review the radiation belts synchrotron emission characteristics. We present radio sources visibility products (dynamic spectra and radio source location maps, on still frames or movies), which can be used for operation planning. This study clearly shows that a deep understanding of the natural radio emissions at Jupiter is necessary to prepare the future EJSM radar instrumentation. We show that this radio noise has to be taken into account very early in the observation planning and strategies for both JGO and JEO. We also point out possible synergies with RPW (Radio and Plasma Waves) instrumentations.

  16. Natural radio emission of Jupiter as interferences for radar investigations of the icy satellites of Jupiter

    NASA Astrophysics Data System (ADS)

    Cecconi, B.; Hess, S.; Hérique, A.; Santovito, M. R.; Santos-Costa, D.; Zarka, P.; Alberti, G.; Blankenship, D.; Bougeret, J.-L.; Bruzzone, L.; Kofman, W.

    2012-02-01

    Radar instruments are part of the core payload of the two Europa Jupiter System Mission (EJSM) spacecraft: NASA-led Jupiter Europa Orbiter (JEO) and ESA-led Jupiter Ganymede Orbiter (JGO). At this point of the project, several frequency bands are under study for radar, which ranges between 5 and 50 MHz. Part of this frequency range overlaps with that of the natural jovian radio emissions, which are very intense in the decametric range, below 40 MHz. Radio observations above 40 MHz are free of interferences, whereas below this threshold, careful observation strategies have to be investigated. We present a review of spectral intensity, variability and sources of these radio emissions. As the radio emissions are strongly beamed, it is possible to model the visibility of the radio emissions, as seen from the vicinity of Europa or Ganymede. We have investigated Io-related radio emissions as well as radio emissions related to the auroral oval. We also review the radiation belts synchrotron emission characteristics. We present radio sources visibility products (dynamic spectra and radio source location maps, on still frames or movies), which can be used for operation planning. This study clearly shows that a deep understanding of the natural radio emissions at Jupiter is necessary to prepare the future EJSM radar instrumentation. We show that this radio noise has to be taken into account very early in the observation planning and strategies for both JGO and JEO. We also point out possible synergies with RPW (Radio and Plasma Waves) instrumentations.

  17. 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.

  18. Comparison of equatorial electron densities measured by whistlers and by a satellite radio technique

    Microsoft Academic Search

    D. L. Carpenter; R. R. Anderson; T. F. Bell; T. R. Miller

    1981-01-01

    For the first time, data on magnetospheric equatorial electron density from multiple whistler paths have been compared with in situ satellite measurements of electron density along near-equatorial orbits. The whistlers data were recorded at Siple, Antarctica (Lapprox.4.2) on June 28 and July 10, 1978, and at Palmer, Antarctica (Lapprox.2.3) on April 10, 1978. The satellite data were obtained by the

  19. Impact of tropospheric scintillation in the Ku\\/K bands on the communications between two LEO satellites in a radio occultation geometry

    Microsoft Academic Search

    Enrica Martini; Angelo Freni; Luca Facheris; Fabrizio Cuccoli

    2006-01-01

    A theoretical analysis of the impact of clear-air tropospheric scintillation on a radio occultation link between two low Earth orbit satellites in K- and Ku-bands is presented, with particular reference to differential approaches for the measure of the total content of water vapor. The troposphere is described as a spherically symmetric turbulent medium satisfying Kolmogorov theory. Rytov's first iteration solution

  20. Design of a Digital Satellital Radio Receiver using LDGM codes and predistorted M-QAM signals

    Microsoft Academic Search

    G. Quezada; I. Soto; R. Carrasco

    In this paper a new Satellital Digital Audio Broadcasting (S-DAB) system is presented using Low Density Generator Matrix (LDGM) coding and a neural Predistortion to compensate the nonlinear distortion introduced by the High Power Amplifier (HPA). Also complexity considerations are included.

  1. Detection of Transionospheric SuperDARN HF Waves by the Radio Receiver Instrument on the enhanced Polar Outflow Probe Satellite

    NASA Astrophysics Data System (ADS)

    Gillies, R. G.; Yau, A. W.; James, H. G.; Hussey, G. C.; McWilliams, K. A.

    2014-12-01

    The enhanced Polar Outflow Probe (ePOP) Canadian small-satellite was launched in September 2013. Included in this suite of eight scientific instruments is the Radio Receiver Instrument (RRI). The RRI has been used to measure VLF and HF radio waves from various ground and spontaneous ionospheric sources. The first dedicated ground transmission that was detected by RRI was from the Saskatoon Super Dual Auroral Radar Network (SuperDARN) radar on Nov. 7, 2013 at 14 MHz. Several other passes over the Saskatoon SuperDARN radar have been recorded since then. Ground transmissions have also been observed from other radars, such as the SPEAR, HAARP, and SURA ionospheric heaters. However, the focus of this study will be on the results obtained from the SuperDARN passes. An analysis of the signal recorded by the RRI provides estimates of signal power, Doppler shift, polarization, absolute time delay, differential mode delay, and angle of arrival. By comparing these parameters to similar parameters derived from ray tracing simulations, ionospheric electron density structures may be detected and measured. Further analysis of the results from the other ground transmitters and future SuperDARN passes will be used to refine these results.

  2. Satellite emission features in two Seyfert galaxies: New evidence that radio-quiet AGN possess subrelativistic winds

    NASA Technical Reports Server (NTRS)

    Stocke, John T.; Shull, Michael; Granados, Arno F.; Sachs, Elise R.

    1994-01-01

    Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) spectra are presented for three bright Seyfert galaxies including one (PG 1351+64) which possesses blue-displaced absorption features in C IV, Si IV, N V, and Ly-alpha (but not in Mg II) similar to those seen at high redshift in the broad-absorption-line (BAL) quasi-stellar objects (QSOs). Several features of the absorptions in PG 1351+64, including variability seen in archival International Ultraviolet Explorer (IUE) data, confirm their similarity to the BAL clouds rather than to the 'associated absorber' phenomenon which they superficially resemble. In PG 1351+64 'satellite' emission lines (called herein E1 and E2) have been detected nearly symmetrically placed at +/- 4000 km/s around the Mg II emission line; this velocity is just larger than the most blue-displaced of the BALs, suggesting that these two phenomena are related. The satellite line luminosity, L(E1) approximately = (3 x 10(exp 41) erg/s)/sq. h(sub 75), requires a cloud emission measure n(sub e)(exp 2)V(sub c) approximately = (1 x 10(exp 64)/cc)/sq. h(sub 75) at T approximately = 30,000 K. We believe the Mg II lines are produced by 50-90 km/s shocks driven into dense (approximately 10(exp 6)/cc, pre-shock) clouds by the ram pressure of a 0.1 solar mass/yr wind leaving the nucleus at velocity 4000 km/s. The detection of satellite lines in Mg II, the detection of the blue-shifted cloud in H-alpha and H-beta and the nondetection of this cloud in C IV restricts the cloud shocks to velocities v(sub c) less than or = 90 km/s and requires a cloud/wind density contrast greater than or = 10(exp 3). In this model, the emitting clouds are located at distances of R(sub eff) approximately = 10(exp 18-19) cm from the nucleus and are entrained and shock-accelerated to approximately 4000 km/s. The possible detection of similar 'satellite' emission features in the non-BAL Seyfert, Ton 951, suggests that the subrelativistic wind that accelerates BAL clouds is a physical feature of many radio-quiet active galactic nuclei (AGN).

  3. Habitats used by black and surf scoters in eastern North America as determined by satellite radio telemetry

    USGS Publications Warehouse

    Perry, M.C.; Kidwell, D.M.; Wells-Berlin, A. M.; Lohnes, E.J.R.; Olsen, G.H.; Osenton, P.C.

    2005-01-01

    Satellite radio telemetry was used to determine the movements and habitats of black scoters (Melanitta nigra) and surf scoters (Melanitta perspicillata) in eastern North America. A total of 21 surf scoters were instrumented during five years (2001-05) and 32 black scoters were instrumented during three years (2002-04) with implanted PTT 100 satellite transmitters (39 g) with external antenna. Nesting habitat of black scoters was more open than surf scoters (44% vs. 11%), whereas nesting habitat for surf scoters was located in more forested areas (66% vs. 20%). Locations of black scoters in breeding areas on average were at significantly higher latitude and lower elevations than sites used by surf scoters. Satellite telemetry determined that James Bay was the major molting area for male black and surf scoters, although some males molted along the coast of Labrador-Newfoundland. Black scoters instrumented on the Restigouche River, which is a major staging area, were widely distributed along the Atlantic Coast from Cape Cod to Georgia during winter. Major wintering areas for black scoters were Cape Cod (Martha's Vineyard and Nantucket Island), Long Island, and New Jersey. In these northern marine wintering areas, black scoters were located farther from shore (4.2 km) and in deeper water (8.3 m) than black scoters in more southern estuarine areas, where distance from shore was 3.1 km and water depth was 5.2 m. Surf scoters instrumented in Chesapeake Bay in late winter showed a strong tendency to return to the Bay the following winter after they had migrated to and from breeding areas. In Chesapeake Bay, black scoters and surf scoters were located mostly in mesohaline areas that had similar water depths (5.1 m vs. 7.5 m) and distances from shore (3.0 km vs. 2.9 km). Distance from shore and depth of water increased over time during the winter for both species. Updated information from the ARGOS Systems aboard the NOAA satellites on scoter movements was made accessible on the Patuxent Website.

  4. Diagnostics of magnetospheric electron density and irregularities at altitudes <5000 km using whistler and Z mode echoes from radio sounding on the IMAGE satellite

    Microsoft Academic Search

    V. S. Sonwalkar; D. L. Carpenter; T. F. Bell; M. Spasojevic; J. Li; X. Chen; A. Venkatasubramanian; J. Harikumar; R. F. Benson; W. W. L. Taylor; B. W. Reinisch

    2004-01-01

    When the Radio Plasma Imager (RPI) on the IMAGE satellite operates in the inner plasmasphere and at moderate to low altitudes over the polar regions, pulses emitted at the low end of its 3-kHz to 3-MHz sounding frequency range can propagate in the whistler mode and\\/or in the Z mode. During soundings with both 25.6-ms pulses and 3.2-ms pulses, whistler

  5. Microelectromechanical system radio frequency switches in a picosatellite mission

    NASA Astrophysics Data System (ADS)

    Yao, J. Jason; Chien, Charles; Mihailovich, Robert; Panov, Viktor; DeNatale, Jeffrey; Studer, Judy; Li, Xiaobin; Wang, Anhua; Park, Sangtae

    2001-12-01

    Rockwell Science Center (RSC) has designed and implemented a microelectromechanical-system- (MEMS-) based radio frequency switch experiment in a miniature satellite format (picosat) as an initial demonstration of MEMS for space applications. This effort is supported by DARPA-MTO, and the mission was conducted with Aerospace Corporation and Stanford University as partners. MEMS surface-micromachined metal contacting switches were manufactured and used in a simple, yet informative, experiment aboard the miniature satellites to study the device behavior in space, and its feasibility for space applications in general. Communication links between multiple miniature satellites, as well as between the satellites and ground, were also achieved using communications circuits constructed and provided by RSC. Details of both the MEMS and radio communications and networking efforts will be discussed in this paper.

  6. OLFAR - orbiting low frequency array; using a satellite swarm for building a space-based radio telescope for low frequencies

    Microsoft Academic Search

    M. J. Bentum; A. J. Boonstra; C. J. M. Verhoeven; Veen van der A. J; E. K. A. Gill; N. Saks; H. Falcke; M. Klein-Wolt; R. T. Rajan; S. J. Wijnholds; M. Arts; Klooster van't K; F. Beliën; A. Meijerink; B. Monna; J. Rotteveel; M. A. Boer; E. Bongers; E. Boom; Tuijl van E; Staveren van A

    2010-01-01

    In radio astronomy, as in astronomy in general, a wide range of frequencies is observed as each spectral band offers a unique window to study astrophysical phenomena. In the recent years, new observatories have been designed and built at the extreme limits of the radio spectrum. For the low frequencies several Earth-based radio telescopes are constructed at this moment. In

  7. Onboard Photo: Astronauts Use Shuttle Amateur Radio Experiment II (SAREX-II)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Space Shuttle Discovery (STS-56) onboard photo of Pilot Stephen S. Oswald (wearing a headset) uses the Shuttle Amateur Radio Experiment II (SAREX-II) while sitting at the pilot's station on the forward flight deck. Oswald smiled from behind the microphone as he talks to amateur radio operators on Earth via the SAREX equipment. SAREX cables and the interface module freefloat in front of Oswald. The anterna located in the forward flight deck window is visible in the background. SAREX was established by NASA, the American Radio League/Amateur Radio Satellite Corporation and the Johnson Space Center (JSC) Amateur Radio Club to encourage public participation in the space program through a program to demonstrate the effectiveness of conducting short-wave radio transmissions between the Shuttle and ground-based radio operators at low-cost ground stations with amateur and digital techniques.

  8. The effect of secular resonances on the long-term orbital evolution of uncontrollable objects on satellite radio navigation systems in the MEO region

    NASA Astrophysics Data System (ADS)

    Bordovitsyna, T. V.; Tomilova, I. V.; Chuvashov, I. N.

    2012-09-01

    We present the results of the study of long-term orbital evolution of space debris objects, formed from end-of-life space vehicles (SV) of satellite radio navigation systems in the medium Earth orbit (MEO) region. Dynamical features of the evolution of objects in this region have been studied on the basis of 20-year laser surveillance with the Etalon-1 and Etalon-2 satellites and the results of numerical simulation of the long-term evolution of operating and disposal orbits of uncontrolled GLONASS and GPS SVs. It is shown that perturbations from secular lunisolar resonances produce an eccentricity growth for orbits with inclinations chosen for navigation constellations; this significantly changes the positions of these orbits in space and results in the ingress of end-of-life objects into the area of operating SVs.

  9. 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.

  10. Satellite positioning

    NASA Technical Reports Server (NTRS)

    Colombo, Oscar L.; Watkins, Michael M.

    1991-01-01

    Developments in satellite positioning techniques and their applications are reviewed on the basis of the theoretical and practical work published by U.S. researchers in 1987-1990. Current techniques are classified into two main categories: satellite laser tracking and radio tracking. Particular attention is given to the Geoscience Laser Ranging System, the Lunar Laser Ranging concept; GPS ephemerides determination, fiducial networks, and reference frame; static GPS positioning; and kinematic GPS positioning.

  11. STS-35 Shuttle Amateur Radio Experiment (SAREX) equipment stowed on middeck

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-35 Shuttle Amateur Radio Experiment II (SAREX-II) window antenna is shown in its stowage location (inside the window shade and filter kit) on the middeck of JSC's Full Fuselage Trainer (FFT) located in the Mockup and Integration Laboratory (MAIL) Bldg 9A. The antenna was built at no cost to the government by the Motorola Amateur Radio Club in Schaumburg, Illinois. SAREX was designed to conduct shortwave radio transmissions between ground amateur radio operators and a licensed onboard operator (in this case, Parise). Parise's call letters are WA4SIR. SAREX will communicate with amateur stations in Line-of-Site (LOS) of Columbia, Orbiter Vehicle (OV) 102, in one of four transmission modes: voice, Slow Scan Television (SSTV), data or (uplink only) Fast Scan Television (FSTV). SAREX is a jont effort of NASA and the American Radio Relay League (ARRL) / Amateur Radio Satellite Corporation (AMSAT).

  12. STS-35 Shuttle Amateur Radio Experiment (SAREX) equipment held by R. Parise

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-35 Shuttle Amateur Radio Experiment II (SAREX-II) window antenna is held by Payload Specialist Ronald A. Parise outside the JSC Full Fuselage Trainer (FFT) located in the Mockup and Integration Laboratory (MAIL) Bldg 9A. The antenna was built at no cost to the government by the Motorola Amateur Radio Club in Schaumburg, Illinois. SAREX was designed to conduct shortwave radio transmissions between ground amateur radio operators and a licensed onboard operator (in this case, Parise). Parise's call letters are WA4SIR. SAREX will communicate with amateur stations in Line-of-Site (LOS) of Columbia, Orbiter Vehicle (OV) 102, in one of four transmission modes: voice, Slow Scan Television (SSTV), data or (uplink only) Fast Scan Television (FSTV). SAREX is a jont effort of NASA and the American Radio Relay League (ARRL) / Amateur Radio Satellite Corporation (AMSAT).

  13. Satellite launchers

    Microsoft Academic Search

    Y. Sillard

    1976-01-01

    Problems in the selection or development of a suitable launcher for West European (ESRO) satellite projects are examined. Selection of the number of stages and of solid or liquid propellant are weighed. Test and vibration stands, the Pogo effect, and advantages of inertial navigation over radio guidance techniques are discussed. The importance of reliability and backup redundancy systems is emphasized.

  14. The effect of the troposphere on radio wave propagation in a ground-satellite-ground communications system

    Microsoft Academic Search

    S. Ogulewicz

    1979-01-01

    The principal effects of the troposphere on radio wave propagation at centimeter wavelengths are described, with emphasis on space communications systems operating at frequencies above 10 GHz. These effects include: absorption by atmospheric gases, absorption and scattering by hydrometeors, noise emission from absorbing media, antenna beam divergence due to normal refraction, slow fading due to large-scale variations of refractive index,

  15. 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)

  16. Transit - The first navigational satellite system

    Microsoft Academic Search

    G. Richards

    1979-01-01

    The Transit navigational satellite system, providing fixes of high accuracy for ships, is discussed. The Transit satellite, with an orbit of about 1100 km, uses a radio-Doppler navigation method in which the ship's position is calculated from the observed change in the received frequency of the satellite's radio transmissions. The satellite carries an ultra-stable oscillator to control the transmitter frequency,

  17. Migration and wintering areas of American Bitterns (Botaurus lentiginosus) that summer in central North America as determined by satellite and radio telemetry, 1998-2003

    USGS Publications Warehouse

    Huschle, Guy; Toepfer, John E.; Douglas, David C.

    2013-01-01

    Twenty adult male American Bitterns (Botaurus lentiginosus) were marked on summer range in central North America with satellite tracking Platform Transmitter Terminals (PTTs) to document migration routes and wintering range. Nineteen complete fall migration routes were documented for 17 individuals. Of the successful migrations, 63% (n = 12) went to southern Florida, 32% (n = 6) to southern Louisiana, and 5% (n = 1) to the Gulf coast of Texas. Spring migrations for nine birds were documented, and 78% (n = 7) showed fidelity to breeding range. Two complete migrations for two individuals were documented, and they demonstrated fidelity to winter range. The longest, fastest movement documented was 2,300 km in less than 74 hr. Extensive, post-breeding dispersal was not observed in the adult male American Bitterns in this study. Six male American Bitterns were marked with PTTs on winter range in Florida and Texas. Spring migration for these birds was documented to Nebraska, North Dakota, Saskatchewan, Manitoba and Ontario. Sixty-seven American Bitterns were marked with Very High Frequency radio transmitters on summer ranges, and 16% (n = 11) were located on wintering grounds used by the satellite-tracked birds, further documenting the importance of the Everglades and the Louisiana coast as winter habitat for American Bitterns that breed in Central North America.

  18. Impairment of radio wave signal by rainfall on fixed satellite service on earth-space path at 37 stations in Nigeria

    NASA Astrophysics Data System (ADS)

    Omotosho, T. V.; Oluwafemi, C. O.

    2009-06-01

    This study investigates the effect of rainfall on horizontally polarized radio waves for fixed satellite service at Ku, Ka and V bands for links to the recently launched Nigeria Communication Satellite one (NigComSat-1), for annual time availabilities of 99-99.99% in an average year for 37 stations in Nigeria. The results obtained at Ku-band downlink shows that 99.99% availability is possible in all the 37-stations in Nigeria. At Ka-band downlink the results also show that only 99.9% availability is practicable in all the 37 stations in Nigeria. At V-band downlink, 99.99% availability is also not possible in all the 37 stations in Nigeria. An availability level of 99.9% is only practicable in the North-West (NW) and North-East (NE) regions, where the attenuation is between 14 and 17.9 dB. Total fade out of signals during rainfall are probable in the South-South (SS), South-East (SE), South-West (SW) and Middle-Belt (MB) regions at 99.9% availability.

  19. S-band dual-path dual-polarized antenna system for satellite digital audio radio service (SDARS) application

    Microsoft Academic Search

    Young-Pyo Hong; Jung-Min Kim; Soon-Chul Jeong; Dong-Hyun Kim; Mun-Ho Choi; Yongshik Lee; Jong-Gwan Yook

    2006-01-01

    This paper presents a novel compact dual-polarized antenna system for S-band satellite digital broadcasting receivers. The demonstrated antenna system consists of a low form factor dual-polarized antenna pair and two-stage low-noise amplifiers (LNAs) integrated with each antenna. One antenna is a low-profile annular ring patch antenna having a 90° phase-delay element for circular polarization (CP) and the other antenna is

  20. Geometrical optics phase matching of radio occultation signals

    Microsoft Academic Search

    Arne Skov Jensen; Martin S. Lohmann; Alan Steen Nielsen; Hans-Henrik Benzon

    2004-01-01

    Remote measurements of the atmospheric state can be performed by radio occultation between satellites, a GPS satellite transmitting a radio signal to a receiving low Earth orbit (LEO) satellite, or between LEO satellites. The bending angle of the traversing optical ray can be measured by detecting the Doppler shift of radio signals. The bending angle is an integrated measure of

  1. Radio Science Observations of the Mars Express December 2013 Phobos Flyby and Implications for the Satellite's Gravity Field

    NASA Astrophysics Data System (ADS)

    Andert, T.; Paetzold, M.; Rosenblatt, P.; Lainey, V.; Pasewaldt, A.; Oberst, J.; Jaumann, R.; Thuillot, W.; Remus, S.; Gurvits, L.; Pogrebenko, S.; Bocanegra Bahamon, T.; Cimo, G.; Duev, D.; Molera Calves, G.

    2014-12-01

    On 29th December 2013, the European spacecraft Mars Express performed a very close flyby at the Martian moon Phobos dedicated to the radio science experiment MaRS. The flyby distance was 58 km, the closest ever. Almost 32 hours of continuous tracking data were collected by ESTRACK (35 m) and DSN (70 m) ground station antennas. 31 VLBI antennas worldwide also recorded the radio signal. The tracking data were interrupted by occultations of approximately 1 hour duration in each orbit revolution, when the spacecraft in Mars orbit disappeared behind the planet as seen from the ground station. Images were taken with the Super Resolution Channel (SRC) of the High Resolution Stereo Camera (HRSC) onboard Mars Express before and after the flyby in order to improve the ephemeris of Phobos. The gravity field of Phobos was estimated from a close MEX flyby in 2010 at a distance of 77 km. The derived second degree and order gravity coefficients, however, showed large errors and could not resolve the interior structure of Phobos. Hence, the close flyby in 2013 was the opportunity to estimate the gravity field of Phobos at a higher precision because of the closer flyby distance, improved Phobos ephemeris obtained from the HRSC/SRC camera, and longer observation times with the ground station antennas. We aim at measurements of the gravity coefficients C20 and C22, which are linked with the main moments of inertia of the body. By comparison with the Phobos shape model and assuming a homogeneous mass distribution these can help in interpretations of the internal structure of Phobos. The main contribution to the error budget of the gravity field is caused by the uncertainty of the Phobos ephemeris, which potentially can be improved by HRSC/SRC observations.

  2. Corporate Strategy Corporate Strategy

    E-print Network

    Zharkova, Valentina V.

    Corporate Strategy 2010-2020 Corporate Strategy 2010-2020 #12;S C I E N C E A N D T E C H N O L O G Strategic themes 16 Solutions for global challenges 18 Inspiring and involving 20 Sustaining research international influence 28 Strategic enablers 30 Developing our people 32 Financial sustainability 34 Efficient

  3. Handset antennas using satellite pack for mobile satellite telephone

    Microsoft Academic Search

    H. Arai; H. Hoshino; T. Sato; Y. Otsu

    1997-01-01

    The Engineering Test Satellite-N (ETS-N) planned to be launched about 2002 in Japan will test S-band satellite mobile commnunications and broadcasting systems by using geostationary satellite. To realize the satellite handy phone service and CD quality radio, it is required to develop a high-performance multi-beam satellite antenna of more than ten meters deployable reflector and innovative feed system, a high

  4. A comparison of field-strengths of 164 kHz radio waves transmitted from Tashkent and received at Ahmedabad with flare-time solar X-ray emissions measured in satellites

    Microsoft Academic Search

    S. C. Chakravarty; K. R. Ramanathan

    1972-01-01

    Conclusion  The comparison of X-ray flares observed in satellites and their manifestation in the field-strength records of 164 kHz radio\\u000a waves received at Ahmedabad from Tashkent show that almost all the flares between 0200–1200 hr U.T. during the period 27 October\\u000a to 3 November, 1968, were able to influence the signal intensity. The starting time and peak time of the X-ray

  5. The Era of Experimental Satellites: Where to Go from Here.

    ERIC Educational Resources Information Center

    Casey-Stahmer, Anna

    1979-01-01

    Reviews developments of experimental satellite programs and their relationship to those operational satellite systems in existence or planned for use by private communications corporations and government agencies. Emphasizes issues related to the planning and availability of satellite systems. (JMF)

  6. Satellite broadcasting in France

    NASA Astrophysics Data System (ADS)

    Georgy, Jean

    1988-12-01

    A review is presented of the role to be played by direct broadcast satellite (DBS) in changing TV and radio broadcasting in France. In addition, the status of the TDF1 and TDF2 satellite program is assessed. Satellite design is discussed along with a description of the propulsion, service, solar array, communication and antenna modules. Services offered by the TDF1 and TDF2 system are presented. Finally, trends that DBS follow-on systems must cope with are given.

  7. The effect of solar radio bursts on the GNSS radio occultation signals

    NASA Astrophysics Data System (ADS)

    Yue, Xinan; Schreiner, William S.; Kuo, Ying-Hwa; Zhao, Biqiang; Wan, Weixing; Ren, Zhipeng; Liu, Libo; Wei, Yong; Lei, Jiuhou; Solomon, Stan; Rocken, Christian

    2013-09-01

    radio burst (SRB) is the radio wave emission after a solar flare, covering a broad frequency range, originated from the Sun's atmosphere. During the SRB occurrence, some specific frequency radio wave could interfere with the Global Navigation Satellite System (GNSS) signals and therefore disturb the received signals. In this study, the low Earth orbit- (LEO-) based high-resolution GNSS radio occultation (RO) signals from multiple satellites (COSMIC, CHAMP, GRACE, SAC-C, Metop-A, and TerraSAR-X) processed in University Corporation for Atmospheric Research (UCAR) were first used to evaluate the effect of SRB on the RO technique. The radio solar telescope network (RSTN) observed radio flux was used to represent SRB occurrence. An extreme case during 6 December 2006 and statistical analysis during April 2006 to September 2012 were studied. The LEO RO signals show frequent loss of lock (LOL), simultaneous decrease on L1 and L2 signal-to-noise ratio (SNR) globally during daytime, small-scale perturbations of SNR, and decreased successful retrieval percentage (SRP) for both ionospheric and atmospheric occultations during SRB occurrence. A potential harmonic band interference was identified. Either decreased data volume or data quality will influence weather prediction, climate study, and space weather monitoring by using RO data during SRB time. Statistically, the SRP of ionospheric and atmospheric occultation retrieval shows ~4% and ~13% decrease, respectively, while the SNR of L1 and L2 show ~5.7% and ~11.7% decrease, respectively. A threshold value of ~1807 SFU of 1415 MHz frequency, which can result in observable GNSS SNR decrease, was derived based on our statistical analysis.

  8. Allocations by the 1992 World Administrative Radio Conference

    NASA Astrophysics Data System (ADS)

    Heyward, Ann O.

    1992-08-01

    An overview of the 1992 World Administrative Radio Conference is presented with viewgraphs. Allocations of radio frequency spectrum are addressed. Mobile satellite service, broadcast satellite service, and uplink power control beacons are also addressed.

  9. Radio science investigations with Voyager

    NASA Technical Reports Server (NTRS)

    Eshleman, V. R.; Tyler, G. L.; Anderson, J. D.; Fjeldbo, G.; Levy, G. S.; Wood, G. E.; Croft, T. A.

    1977-01-01

    Radio links to and from the Voyager spacecraft will be used for occultation measurements of planetary and satellite atmospheres and ionospheres, the rings of Saturn, the solar corona, and the general-relativistic time delay for radio wave propagation through the solar gravity field. In addition, the radio link measurements may provide information on the gravity fields of the planets, the masses of the satellites, properties of the interplanetary medium, and long-wavelength gravitational radiation propagation in the solar system.

  10. Telemetry Data Collection from Oscar Satellite

    NASA Technical Reports Server (NTRS)

    Haddock, Paul C.; Horan, Stephen

    1998-01-01

    This paper discusses the design, configuration, and operation of a satellite station built for the Center for Space Telemetering and Telecommunications Laboratory in the Klipsch School of Electrical and Computer Engineering Engineering at New Mexico State University (NMSU). This satellite station consists of a computer-controlled antenna tracking system, 2m/70cm transceiver, satellite tracking software, and a demodulator. The satellite station receives satellite,telemetry, allows for voice communications, and will be used in future classes. Currently this satellite station is receiving telemetry from an amateur radio satellite, UoSAT-OSCAR-11. Amateur radio satellites are referred to as Orbiting Satellites Carrying Amateur Radio (OSCAR) satellites as discussed in the next section.

  11. Civil satellite navigation and location systems

    NASA Astrophysics Data System (ADS)

    Blanchard, W. F.

    1989-05-01

    The use of satellites for civil navigation and location, including satellites not necessarily launched for that purpose, is reviewed. In particular, attention is given to differences between civil and military satellites; civil use of military systems and the associated commercial considerations and regulatory issues; the use of communication satellites; and radiodetermination satellite service based on geostationary satellites. The discussion also covers integration with ground-based radio-navigation systems; existing radio-navigation satellite systems; and the Starfix, Geostar/Locstar, Starfind, Navsat, and Rexstar systems.

  12. Methods of satellite oceanography

    NASA Technical Reports Server (NTRS)

    Stewart, R. H.

    1985-01-01

    The theoretical basis for remote sensing measurements of climate and ocean dynamics is examined. Consideration is given to: the absorption of electromagnetic radiation in the atmosphere; scattering in the atmosphere; and satellite observations using visible light. Consideration is also given to: the theory of radio scatter from the sea; scatter of centimeter waves from the sea; and the theory of operation of synthetic aperture radars. Additional topics include: the coordinate systems of satellite orbits for oceanographic remote sensing applications; the operating features of the major U.S. satellite systems for viewing the ocean; and satellite altimetry.

  13. (Astro)Physics 343 Observational Radio Astronomy

    E-print Network

    Baker, Andrew J.

    . Last year: "Current and Future Radio Astronomy Projects" This year: the search for extraterrestrial intelligence? the New Jersey roots of radio astronomy? why the Iridium telecommunications satellites are evil

  14. Strategies for Protecting Radio Astronomy

    Microsoft Academic Search

    R. J. Cohen

    \\u000a Our view of the radio universe is increasingly obscured by rising levels of human-generated radio and electrical interference.\\u000a Transmissions from satellites pose a particularly serious threat since they can affect radio telescopes anywhere on Earth.\\u000a Consumer devices not intended as radio transmitters, such as computers and microwave ovens, add to the growing levels of electromagnetic\\u000a pollution. Coordinated action is needed

  15. Improvements in search and rescue distress alerting and locating using satellites

    NASA Technical Reports Server (NTRS)

    Brandel, D. L.; Schmid, P. E.; Trudell, B. J.

    1976-01-01

    This paper describes a system concept for search and rescue which is capable of making a major contribution to saving lives and reducing the search time for downed aircraft. In addition, a beacon location experiment is described using the Amateur Radio Satellite Corporation Oscar-6 and Oscar-7 spacecraft. The purpose of this experiment was to demonstrate the system concept above by determining the geographical location of a low power 'distress beacon' via satellite based on a single pass of Doppler frequency measurements. Preliminary results are presented showing beacon location recovery on the order of 10 km with indications that an order of magnitude improvement is entirely possible. This experiment is in support of NASA's current exploration into the role satellites might play in providing much needed improvements in the reliability, coverage and accuracy of present search and rescue procedures.

  16. Corporate Governance

    Microsoft Academic Search

    Luigi Zingales

    1998-01-01

    This paper summarizes my own personal view of what corporate governance is about. I argue that it makes sense to discuss corporate governance only in an incomplete contract world. In this world, the notion of corporate governance is intrinsically related to the definition of the firm. In this respect, the shortcomings of the existing definitions of the firm are reviewed

  17. Corporate Environmental Social Responsibility: Corporate \\

    Microsoft Academic Search

    Hope M. Babcock

    2010-01-01

    This article focuses on the extent to which unenforceable voluntary initiatives undertaken by corporations can change corporate behavior to make businesses more environmentally responsible, i.e. not only comply with the law, but to do more than the law actually requires of them. These initiatives, loosely gathered under the umbrella of a movement called corporate social responsibility (CSR), are often proposed

  18. Radio Galaxies.

    ERIC Educational Resources Information Center

    Downes, Ann

    1986-01-01

    Provides background information on radio galaxies. Topic areas addressed include: what produces the radio emission; radio telescopes; locating radio galaxies; how distances to radio galaxies are found; physics of radio galaxies; computer simulations of radio galaxies; and the evolution of radio galaxies with cosmic time. (JN)

  19. Global diagnostics of the ionospheric perturbations related to the seismic activity using the VLF radio signals collected on the DEMETER satellite

    Microsoft Academic Search

    O. Molchanov; A. Rozhnoi; M. Solovieva; O. Akentieva; J. J. Berthelier; M. Parrot; F. Lefeuvre; P. F. Biagi; L. Castellana; M. Hayakawa

    2006-01-01

    The analysis of the VLF signals radiated by ground transmitters and received on board of the French DEMETER satellite, reveals a drop of the signals (scattering spot) connected with the occurrence of large earthquakes. The extension of the \\

  20. Impact of the direct sequence spread spectrum signals from the global satellite navigation system GLONASS on radio astronomy: problem and proposed solution

    Microsoft Academic Search

    J. E. B. Ponsonby

    1994-01-01

    The GLONASS satellites use direct sequence spread spectrum with a P-code chip rate of 5.11 MHz. On their L1 channels near 1600 MHz they also carry a 0.511 MHz chip rate C\\/A-code. The satellites are distinguished by FDMA having carrier frequencies spaced 0.5625 MHz apart. The digital code sequences are used directly to switch the phase of the carriers. This

  1. Satellite (IRLS) tracking of elk

    NASA Technical Reports Server (NTRS)

    Buechner, H. K.

    1972-01-01

    The practicability of tracking free roaming animals in natural environments by satellite systems is reported. Satellite systems combine continuous tracking with simultaneous monitoring of physiological and environmental parameters through a combination of radio tracking and biotelemetric ground systems that lead to a better understanding of animal behavior and migration patterns.

  2. Satellite networks for education.

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

    Consideration of satellite-based educational networking. The characteristics and structure of networks are reviewed, and pressures within the educational establishment that are providing motivation for various types of networks are discussed. A number of studies are cited in which networking needs for educational sectors and services are defined. The current status of educational networking for educational radio and television, instructional television fixed services, inter- and intrastate educational communication networks, computer networks, cable television for education, and continuing and proposed educational experiments using NASA's Applications Technology Satellites is reviewed. Possible satellite-based educational telecommunication services and three alternatives for implementing educational satellite systems are described. Some remarks are made concerning public policy aspects of future educational satellite system development.

  3. Radio Astronomy Radio astronomy

    E-print Network

    Metchev, Stanimir

    ;#12;Arecibo 300m telescope #12;Radio interferometer #12;Radio interferometer Very Large Array (VLA) (New;WestVirginia) #12;Centimeter radio astronomy HI 21cm line emission traces the distribution of atomic hydrogen. Dust: far-Infrared (60-240micron) map NASA/GSFC Atomic hydrogen (HI): 21cm emission-line Dickey & Lockman

  4. Corporate Social Responsibility and Corporate Citizenship: Towards Corporate Accountability

    Microsoft Academic Search

    CARMEN VALOR

    2005-01-01

    f you were a newcomer in the field of business and social issues and you started browsing academic literature, surely you would be bewildered by a number of different terms and definitions that imply similar or identical meanings: corporate social responsi- bility, public responsibility, corporate social responsibilities, corporate societal responsibility, corporate social responsiveness, corporate social performance, corporate citizenship, business citizenship,

  5. Weather, land satellite sale

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    President Ronald Reagan announced on March 8 plans to sell to private industry the nation's land and meteorological remote-sensing satellites, including the responsibility for any future ocean-observing systems. According to the plan, the private firm successful in its bid to buy the five satellites would sell back to the government the data received by the satellites. The Reagan administration says the sale will save money and will put activities appropriate for commercial ventures into the commercial sector. Response to the announcement from scientists and congressmen has been anything but dulcet; one senator, in fact, charges that the Commerce Department and the corporation most likely to purchase the satellites are engaged in a ‘sweetheart deal.’

  6. Corporal Punishment

    Microsoft Academic Search

    Carolyn Hilarski

    2004-01-01

    It is vital to study and understand the underlying conditions that support and maintain the almost universal positive attitudes about the use of corporal punishment with children. Corporal punishment is a form of violence against children that affects child development and may possibly be a link to later violent behavior. Currently, the scientific community is in great debate regarding the

  7. Copyright Quick Guide Television and Radio Broadcasts

    E-print Network

    Blows, Mark

    Copyright Quick Guide Television and Radio Broadcasts Overview The University has extensive rights to copy and communicate television and radio broadcasts for educational purposes. This includes making ­ this includes free-to-air, satellite and cable television broadcasts, along with radio broadcasts. As a result

  8. Magnetospherically reflected, specularly reflected, and backscattered whistler mode radio-sounder echoes observed on the IMAGE satellite: 2. Sounding of electron density, ion effective mass (meff), ion composition (H+, He+, O+), and density irregularities along the geomagnetic field line

    NASA Astrophysics Data System (ADS)

    Sonwalkar, V. S.; Reddy, A.; Carpenter, D. L.

    2011-11-01

    A companion paper by Sonwalkar et al. (2011) provided new details of whistler mode radio sounding of the altitude range below ˜5000 km by the Radio Plasma Imager (RPI) instrument on the IMAGE satellite. That paper presented frequency-vs- group time delay records of echoes whose raypaths either 1) reversed direction through refraction at altitudes above the ionosphere where the wave frequency was approximately equal to the local lower hybrid resonance frequency flh (magnetospherically reflected or MR echoes), or 2) returned to IMAGE from reflection points along the sharp lower boundary of the ionosphere at ˜90 km (obliquely incident (OI) or normally incident (NI) specularly reflected (SR) echoes). The MR and OI echo paths were shown to form narrow loops, while the NI echo followed the same raypath down and back. Furthermore, the echoes were found to be discrete or broadened in time delay either by multipath propagation or by scattering from field aligned irregularities (FAIs). We begin with a direct interpretive approach, employing a combination of refractive index diagrams, ray tracings, and a plasma density model to predict the detailed frequency-vs-time properties of echoes detected when the sounder is operated over a wide range of whistler mode frequencies (typically 6 kHz to 63 kHz) and the satellite is either above or below the altitude of the maximum flh along the geomagnetic field line B0 in the upper ionosphere. We then consider the inverse problem, estimation of the parameters of the prevailing plasma density model from the observed echo properties. Thanks to variations in the sensitivity of the various echo forms to the altitude profiles of electron density and ion effective mass meff, we use the observed frequency-vs- group time delay (tg - f) details of simultaneously received MR and SR echoes to infer the properties of a diffusive equilibrium model of the plasma, including estimates of the ion composition in the important transition region from the O+-dominated ionosphere to the light ion regime above. Our results on electron density and ion composition measurements are in general agreement with those obtained from in situ measurements on the IMAGE and DMSP-F15 satellites, with bottomside sounding results from nearby Ionosondes, and with values obtained from the IRI-2007 model. We also demonstrate a method of estimating the scale sizes and locations of FAIs located along or near WM echo paths.

  9. 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…

  10. Radio observations of Planck clusters

    NASA Astrophysics Data System (ADS)

    Kale, R.

    2013-04-01

    Recently, a number of new galaxy clusters have been detected by the ESA-Planck satellite, the South Pole Telescope, and the Atacama Cosmology Telescope using the Sunyaev-Zel'dovich effect. Several of the newly detected clusters are massive, merging systems with disturbed morphology in the X-ray surface brightness. Diffuse radio sources in clusters, called giant radio halos and relics, are direct probes of cosmic rays and magnetic fields in the intra-cluster medium. These radio sources are found to occur mainly in massive merging clusters. Thus, the new SZ-discovered clusters are good candidates to search for new radio halos and relics. We have initiated radio observations of the clusters detected by Planck with the Giant Metrewave Radio Telescope. These observations have already led to the detection of a radio halo in PLCKG171.9-40.7, the first giant halo discovered in one of the new Planck clusters.

  11. Corporate Information

    NSDL National Science Digital Library

    Regnery, George Matthew.

    Gregory Regnery has put together an extensive list of sites with information on corporations from around the world. The aim of the site is to allow people to find information about a particular company quickly. Hence, the web sites featured here consist mainly of business directories and stock exchanges. Both domestic and international sources of corporate information are available; resources are sorted by country. This web site also contains a list of definitions for security identifiers and company extensions used by other countries.

  12. Radio loud far-infrared galaxies

    NASA Technical Reports Server (NTRS)

    Dey, Arjun; Vanbreugel, Wil; Shields, Joseph C.

    1990-01-01

    The first results are presented of a multiwavelength study of Infrared Astronomy Satellite (IRAS) galaxies with excess radio emission. The sample was selected by cross correlating the IRAS Faint Source Survey, and the Point Source Catalogue with the Texas radio survey. Recent optical (imaging and spectroscopic) and radio (VLA) observations are discussed. These observations will be used to investigate possible connections between radio galaxy activity, star formation and galaxy interactions.

  13. Hitchhiker payloads for new commercial satellite services

    NASA Astrophysics Data System (ADS)

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

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

  14. Financing satellites: easier said than done

    Microsoft Academic Search

    Stéphane Chenard

    1999-01-01

    The financing of satellites, as of most telecommunications equipment generally, used to be a simple thing: governments would dip into the treasury, while the few private groups which owned satellites also had the cash to rely on pure equity financing. Banks became involved to provide simple bridge loans when corporate treasurers preferred to leave the cash untouched; the European Investment

  15. Astronomy research at the Aerospace Corporation. [research projects - NASA programs

    NASA Technical Reports Server (NTRS)

    Paulikas, G. A.

    1974-01-01

    This report reviews the astronomy research carried out at The Aerospace Corporation during 1974. The report describes the activities of the San Fernando Observatory, the research in millimeter wave radio astronomy as well as the space astronomy research.

  16. The Cooperative Satellite Learning Project.

    ERIC Educational Resources Information Center

    Caler, Michelle

    This document describes the Cooperative Satellite Learning Project (CSLP) which is designed to educate students in the areas of space science, engineering, and technology in a business-like atmosphere. The project is a partnership between the National Aeronautics and Space Association (NASA), Allied Signal Technical Services Corporation, and…

  17. How Far Away Are the Satellites?

    NSDL National Science Digital Library

    Glasscoe, Maggi

    In this activity, students calculate the distance from a satellite to a receiving station on Earth. They will learn that radio signals are waves and that wave characteristics can be used to measure properties such as velocity, distance, and time.

  18. Design of the American Mobile Satellite System

    NASA Technical Reports Server (NTRS)

    Kittiver, Charles

    1991-01-01

    This paper presents an overview of the American Mobile Satellite Corporation (AMSC) Mobile Satellite System (MSS). A summary of the mobile satellite (MSAT) design and overall performance is provided. The design and components of both the forward link and return link transponders are described in detail. The design and operation of a unique hybrid matrix amplifier that offers flexible power distribution is outlined. The conceptual design and performance of three types of land mobile antennas are described.

  19. Description of the AMSC mobile satellite system

    NASA Astrophysics Data System (ADS)

    Garner, W. B.

    The American Mobile Satellite Corporation will provide a full range of mobile satellite services through a mobile satellite system dedicated to mobile use in the United States. This paper provides a summary of the system architecture with descriptions of each of the major system elements. The elements are the space segment, network control system, mobile earth terminals and feeder-link earth stations. The general transmission plan is also described.

  20. Theories of Corporate Groups: Corporate Identity Reconceived

    E-print Network

    Harper Ho, Virginia E.

    2012-06-17

    alike have persistently failed to consider the application of these concepts to corporate groups. Beginning from theories of the firm, this Article extends the standard understandings of corporate personhood to develop alternative theories of corporate...

  1. Corporal punishment.

    PubMed

    Zolotor, Adam J

    2014-10-01

    Corporal punishment is used for discipline in most homes in the United States. It is also associated with a long list of adverse developmental, behavioral, and health-related consequences. Primary care providers, as trusted sources for parenting information, have an opportunity to engage parents in discussions about discipline as early as infancy. These discussions should focus on building parents' skills in the use of other behavioral techniques, limiting (or eliminating) the use of corporal punishment and identifying additional resources as needed. PMID:25242709

  2. Satellite navigation method based on user's clock synchronization

    NASA Astrophysics Data System (ADS)

    Yamawaki, Koji

    This paper presents a satellite navigation method which is based on the synchronization of a user clock, using bidirectional satellite communication. This method is effectively applied to cope with the reduction of range-finding data due to satellite failure or limited field of view, and is also applicable to a Radio Determination Satellite System such as Geostar, which uses two geostationary satellites as means of relaying range-finding signals, and supplies communication service at the same time. Analytical results are discussed.

  3. 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.

  4. Ganymede: A New Radio Source

    NASA Technical Reports Server (NTRS)

    Kurth, W. S.; Gurnett, D. A.; Roux, A.; Bolton, S. J.

    1997-01-01

    Observations by the Galileo plasma wave receiver during the first two flybys of Ganymede revealed that this Jovian moon is the source of narrowband electromagnetic radio waves, making it the only satellite in the solar system known to generate non-thermal radio emissions. The emissions are the result of mode-coupling from electrostatic electron cyclotron emissions mu the upper hybrid resonance frequency, similar to non-thermal continuum radiation found at the known magnetized planets.

  5. Radio telescopes

    Microsoft Academic Search

    J. Findlay

    1964-01-01

    A radio telescope is used in radio astronomy to measure the intensity of the radiation received from various parts of the sky. Such a telescope must be able both to detect and to locate faint radio sources of small angular size, and also to measure the brightness distribution across extended radio sources or over large sky areas. Ideally the telescope

  6. Engineering calculations for communications satellite systems planning

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  7. A study of satellite emergency locator systems

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Satellite emergency locator systems were studied. The objective of the study was to determine the feasibility and hardware requirements for satellite systems capable of identifying and locating the position emergency locator transmitters and emergency position indicating radio beacons. Both geosynchronous and near-polar-orbiting satellites were considered. One of the most important aspects of the study was to minimize the cost of the hardware required.

  8. Linearly connected solar power satellite

    Microsoft Academic Search

    Tetsuji Narasaki; Yoshikazu Doui

    1992-01-01

    A study of the system function of Solar Power Satellite (SPS) was conducted considering related technical problems, such as power transmission (loss, heat, failure, and weight) by slip rings between the platform and rotating antenna, location of antenna installation (method of SPS connection), inertial moment of the antenna, DC (Direct Current)-RF (Radio Frequency) amplifier cooling, and maintenance and checkout (configuration).

  9. Regulation of Wire and Radio Communication.

    ERIC Educational Resources Information Center

    Federal Communications Commission, Washington, DC.

    This bulletin reviews early federal regulation of telegraphy, telephone, and radio communications, and the development of the Radio Acts of 1912 and 1927, the Communications Act of 1934, and the Communications Satellite Act of 1962. A large portion of the discussion focuses on the regulatory power and procedures of the Federal Communications…

  10. TDRS orbit determination by radio interferometry

    Microsoft Academic Search

    Michael S. Pavloff

    1994-01-01

    In support of a NASA study on the application of radio interferometry to satellite orbit determination, MITRE developed a simulation tool for assessing interferometry tracking accuracy. The Orbit Determination Accuracy Estimator (ODAE) models the general batch maximum likelihood orbit determination algorithms of the Goddard Trajectory Determination System (GTDS) with the group and phase delay measurements from radio interferometry. ODAE models

  11. Orbiting Low Frequency Array for Radio Astronomy

    E-print Network

    Langendoen, Koen

    either orbit the moon, whilst sampling during the Earth-radio eclipse phase, or orbit the Earth-moon L2 be implemented in moon orbit with today's technology. 1 #12;Number of satellites (or antennas) 10, scalableOrbiting Low Frequency Array for Radio Astronomy Raj Thilak Rajan ASTRON, Dwingeloo, NL rajan

  12. MCPC system and terminal equipment for satellite communication

    Microsoft Academic Search

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

    1982-01-01

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

  13. IMT2000 standards: radio aspects

    Microsoft Academic Search

    R. D. Carsello; R. Meidan; S. Allpress; F. O'Brien; J. A. Tarallo; N. Ziesse; A. Arunachalam; J. M. Costa; E. Berruto; R. C. Kirby; A. Maclatchy; F. Watanabe; H. Xia

    1997-01-01

    One of the key characteristics of IMT-2000 is the advanced radio technologies that will offer a whole new range of capabilities to the users of international mobile telecommunications. This article starts by comparing the significant differences between second-generation mobile systems and the major objectives envisioned for IMT-2000, with particular emphasis on the satellite component. It also describes the flexible modular

  14. The Bubbler and Radio Scintillation

    NSDL National Science Digital Library

    2012-08-03

    This is a lesson about the formation of plasma bubbles in Earth's ionosphere. Plasma bubbles cause stars to twinkle and radio signals from satellites to distort. Learners will build a model ionosphere in order to demonstrate and understand this process. This activity requires special materials including a laser pointer and silicon-based glue.

  15. Corporate manslaughter.

    PubMed

    Berry, Christopher

    2006-01-01

    The Government published its long-awaited draft Bill on the creation of a new criminal offence of corporate manslaughter shortly before the May 2005 general election. The Bill was included in the Queen's Speech after the general election and, with a Labour government back in power, the new offence could be on to the statute book as early as 2006. The Home Affairs Committee and the Work and Pensions Committee announced ajoint inquiry to consider and report on the Bill. This is expected to be completed by the end of 2005. Pressure for reform of the law relating to manslaughter and corporate killing arose out of a series of high profile fatal accidents, including several rail crashes. There has been said to be an increasing concern amongst the public that companies and organisations are not being held sufficiently accountable for deaths caused by their criminal negligence. The author acted in the first of the major cases, representing the directors accused of manslaughter following the Herald of Free Enterprise capsize disaster in 1987. PMID:16454457

  16. Radio Astronomy

    NSDL National Science Digital Library

    Tenenbaum, David

    This article is a Why Files short piece on how astronomers use information from radio astronomy. Contrary to popular belief, large radio telescopes are not looking for signs of life outside our solar system, but are making images of black holes, centers of galaxies, and gamma ray bursts. These phenomena cannot be seen in visible light, but emit radio waves which can be translated into images. The article discusses how this process works, and the information gathered from radio waves.

  17. Communication satellite services for special purpose users

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  18. International Corporate Governance and Corporate Cash Holdings

    Microsoft Academic Search

    Amy Dittmar; Jan Mahrt-Smith; Henri Servaes

    2003-01-01

    Agency problems are an important determinant of corporate cash holdings. For a sample of more than 11,000 firms from 45 countries, we find that corporations in countries where shareholders rights are not well protected hold up to twice as much cash as corporations in countries with good shareholder protection. In addition, when shareholder protection is poor, factors that generally drive

  19. Firefighters' Radios

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Public Technology Inc. asked for NASA assistance to devise the original firefighter's radio. Good short-range radio communications are essential during a fire to coordinate hose lines, rescue victims, and otherwise increase efficiency. Useful firefighting tool is lower cost, more rugged short range two-way radio. Inductorless electronic circuit replaced inductances and coils in radio circuits with combination of transistors and other low-cost components. Substitution promises reduced circuit size and cost. Enhanced electrical performance made radio more durable and improved maintainability by incorporating modular construction.

  20. Corporate Jet

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Gulfstream Aerospace Corporation, Savannah, GA, used a version of a NASA program called WIBCO to design a wing for the Gulfstream IV (G-IV) which will help to reduce transonic drag (created by shock waves that develop as an airplane approaches the speed of sound). The G-IV cruises at 88 percent of the speed of sound, and holds the international record in its class for round-the-world flight. They also used the STANS5 and Profile programs in the design. They will use the NASA program GASP to help determine the gross weight, range, speed, payload and optimum wing area of an intercontinental supersonic business jet being developed in cooperation with Sukhoi Design Bureau, a Soviet organization.

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

    Microsoft Academic Search

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

    2008-01-01

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

  2. Correlation between X-ray Lightcurve Shape and Radio Arrival Time in the Vela Pulsar

    E-print Network

    Gwinn, Carl

    -rays and radio from the RXTE satellite and the Mount Pleasant Radio Observatory in Tasmania. We sought, Madrid, Espa~na 8 University of Tasmania, Tasmania, Australia. 9 Furman University, Greenville, South

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

    NASA Astrophysics Data System (ADS)

    Olsen, Donald; Heymann, Roger

    2007-09-01

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

  4. Corporate Governance and Control

    Microsoft Academic Search

    Patrick Bolton; Marco Becht; Alisa Roell

    2002-01-01

    Corporate governance is concerned with the resolution of collective action problems among dispersed investors and the reconciliation of conflicts of interest between various corporate claimholders. In this survey we review the theoretical and empirical research on the main mechanisms of corporate control, discuss the main legal and regulatory institutions in different countries, and examine the comparative corporate governance literature. A

  5. Corporate architectures for sustainability

    Microsoft Academic Search

    Andrew Griffiths; Joseph A. Petrick

    2001-01-01

    While there exists a growing literature on corporate “green” strategies, there is a research gap about which corporate architectures and organizational change processes enable “green” strategies. This article addresses the research gap in an interdisciplinary manner by focusing on two questions: What conditions characterize ecological and humanly sustainable corporations? What alternative architectures can generate and institutionalize corporate sustainability? Three alternative

  6. Petite Amateur Navy Satellite (PANSAT)

    NASA Technical Reports Server (NTRS)

    Sakoda, D.; Hiser, J. K.

    1989-01-01

    The Naval Postgraduate School's (NPS) Space Systems Academic Group (SSAG) is designing and developing a small communications satellite for launch aboard the shuttle as a complex autonomous payload (CAP). The objectives of PANSAT are three-fold. First, PANSAT will provide an ideal educational tool for the officer students at NPS supporting Space Systems Engineering and Space Systems Operations with hands-on hardware development. Second, the satellite will provide digital store-and-forward communications, or packet radio, for the amateur radio community. The third objective is to provide a low-cost, space-based platform for small experiments. PANSAT will be launched from the shuttle at a nominal altitude of 200 n.m. and an inclination of at least 37 degrees. The satellite weight is 150 lbs. Since there is no attitude control, eight dipole whip antennas will be used to provide isotropic ground coverage for communications. FM digital communications will be used with up-link and down-link on a single frequency in the amateur band of 437.25 MHz. A maximum 50 kHz of bandwidth is envisioned for the satellite. The expected lifetime of the satellite is 1 1/2 to 2 years before atmospheric reentry. The PANSAT design consists of the following: communications subsystem (COMM); computer, or data processor and sequencer (DP&S); power subsystem; structure subsystem; and experiment payload.

  7. Navigation satellites

    NASA Astrophysics Data System (ADS)

    Weiffenbach, George C.

    The evolution, capabilities and uses of satellite-based navigation systems are explored, with emphasis on the accompanying space- and earth-based technologies. Early measurements of the Doppler shifts of Sputnik signals spurred development of the Transit satellite system as a precision navigation aid for Polaris submarines. The development of gravimetric programs to project the actual position of the satellites and the use of high frequency signals to offset ionospheric interference are noted. The design features, performances, and numerous launch and operational failures, of successive Transit spacecraft, i.e., the 5BN, 5C1 and Oscar satellites, are summarized. Details of the operational parameters and design features of the prototype and planned NAVSTAR GPS system are outlined, and plans for a SARSAT search and rescue satellite and the commercial GEOSTAR radionavigation and positioning system are described.

  8. Meteorological satellites

    NASA Technical Reports Server (NTRS)

    Allison, L. J. (editor); Schnapf, A.; Diesen, B. C., III; Martin, P. S.; Schwalb, A.; Bandeen, W. R.

    1980-01-01

    An overview is presented of the meteorological satellite programs that have been evolving from 1958 to the present, and plans for the future meteorological and environmental satellite systems that are scheduled to be placed into service in the early 1980's are reviewed. The development of the TIROS family of weather satellites, including TIROS, ESSA, ITOS/NOAA, and the present TIROS-N (the third generation operational system) is summarized. The contribution of the Nimbus and ATS technology satellites to the development of the operational-orbiting and geostationary satellites is discussed. Included are descriptions of both the TIROS-N and the DMSP payloads currently under development to assure a continued and orderly growth of these systems into the 1980's.

  9. RADIO PLANNING IN MULTIBEAM GEOSTATIONARY SATELLITE NETWORKS

    E-print Network

    , depending on many factors, and in particular on weather conditions. Indeed, dur- ing bad weather in an area. Therefore, if the objective was to maximize the global throughput, it would become non-profitable to assign bandwidth to operators in areas that suffer from bad weather if this bandwidth could be assigned to other

  10. Satellite Broadcast of Graphical Weather Data Flight Tested

    NASA Technical Reports Server (NTRS)

    Mallasch, Paul G.

    2000-01-01

    NASA Glenn Research Center at Lewis Field's aviation Weather Information Communications (WINCOMM) and NASA Langley Research Center's Aviation Weather Information (AWIN) programs collaborated in a flight test and evaluation of a worldwide weather data-link capability using satellites. This successful flight testing moves NASA closer to its goal of developing advanced communications and information technologies to enable high-quality and timely dissemination of aviation weather information to all relevant users on the aviation information network. Recognized as a major contributing factor in aviation accidents and incidents, weather contributes directly or indirectly to nearly 80 percent of fatal general aviation (small private aircraft) accidents. In 1997, the Aeronautics Safety Investment Strategy Team s weather team produced a prioritized list of investment areas under weather accident prevention. Weather data dissemination is the most critical and highest ranked priority on the list. NASA's Aviation Safety Program founded the Aviation Weather Information initiative to focus efforts on significantly reducing the number of weather-related aviation fatalities. Access to accurate and timely weather data could contribute to a major reduction of weather-related incidents and accidents. However, a cost-effective solution has eluded most general aviation pilots because of the high cost of onboard weather radar equipment. Rockwell Collins, through a contract with NASA and in cooperation with WorldSpace Corporation, successfully completed ground and flight testing of a receiver and antenna in Johannesburg, South Africa. This NASA/Rockwell Collins project is an evaluation of worldwide weather data-link capability using transmissions from the Satellite Digital Audio Radio Services (S DARS) AfriStar satellite. Owned and operated by WorldSpace, AfriStar is a geostationary satellite that broadcasts commercial digital audio services to stationary and mobile platforms. S DARS satellites are the most powerful communications satellites produced to date, allowing users to receive signals using simple, low-cost patch antennas instead of more expensive, beam-steered antenna arrays. Engineers connected an inexpensive, commercially available radio receiver to a laptop computer and an antenna designed and built by Rockwell Collins, enabling them to receive WorldSpace signals from the AfriStar satellite during flight tests. WorldSpace broadcast their composite color graphical weather data files, which were multiplexed with normal audio streams, to the flat patch antenna mounted on a single-engine aircraft. The aircraft was equipped with a modified commercial S-DARS receiver, a Global Positioning Satellite (GPS) receiver, and a laptop computer with color display. Continuous data reception occurred during normal aircraft maneuvers performed throughout takeoff, cruise, and landing operations. In addition, engineers monitored receiver power levels during steep turns and banks. In most instances, the receiver was able to maintain acceptable power levels during all phases of flight and to obtain weather data with little or with the successful completion of ground and flight testing of a receiver and antenna in Johannesburg, South Africa, the team has started to prepare for experiments using highspeed aircraft in areas of the world with limited access to timely weather data. NASA plans to provide a more advanced antenna design and consultation support. This successful test of real-time aviation-related weather data is a positive step toward solving communications-specific issues associated with the dissemination of weather data directly to the cockpit.

  11. Satellite Images

    NSDL National Science Digital Library

    In this online, interactive module, students learn about the three types of satellite images (visible, infrared, and water vapor); how to identify basic cloud types and storm systems in satellite images; and demonstrate the basic knowledge necessary to interpret satellite observations. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.

  12. Satellite Imagery

    NSDL National Science Digital Library

    John Nielsen-Gammon

    1996-01-01

    This undergraduate meteorology tutorial focuses on the use of satellite imagery by forecasters. Different types of imagery are discussed, followed by training on the identification of particular types of weather systems.

  13. American Radio Works: Power Trips

    NSDL National Science Digital Library

    Under rules enacted in 1995, members of Congress are effectively banned from accepting any gift worth more than $50, though as this latest investigative radio series from the American RadioWorks team demonstrates, it would appear that members of the House or Senate are still taking many trips at no cost. Working in tandem with a group of graduate students at Northwestern University's Medill School of Journalism, the team catalogued every privately sponsored trip taken by members of Congress since 2000. They discovered that more than $14 million was spent by universities, corporations, and other groups to take these influential persons to a variety of meetings, presentations, and other functions. On this site, visitors can listen to the complete radio presentation, along with obtaining information about how much their own representatives travel and who accepts the most money in trips. Overall, this site is quite informative and more than a bit provocative.

  14. Radio Relays Improve Wireless Products

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Signal Hill, California-based XCOM Wireless Inc. developed radio frequency micromachine (RF MEMS) relays with a Phase II Small Business Innovation Research (SBIR) contract through NASA?s Jet Propulsion Laboratory. In order to improve satellite communication systems, XCOM produced wireless RF MEMS relays and tunable capacitors that use metal-to-metal contact and have the potential to outperform most semiconductor technologies while using less power. These relays are used in high-frequency test equipment and instrumentation, where increased speed can mean significant cost savings. Applications now also include mainstream wireless applications and greatly improved tactical radios.

  15. Heart Monitoring By Satellite

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The ambulance antenna shown is a specially designed system that allows satellite-relayed two-way communications between a moving emergency vehicle and a hospital emergency room. It is a key component of a demonstration program aimed at showing how emergency medical service can be provided to people in remote rural areas. Satellite communication permits immediate, hospital- guided treatment of heart attacks or other emergencies by ambulance personnel, saving vital time when the scene of the emergency is remote from the hospital. If widely adopted, the system could save tens of thousands of lives annually in the U.S. alone, medical experts say. The problem in conventional communication with rural areas is the fact that radio signals travel in line of sight. They may be blocked by tall buildings, hills and mountains, or even by the curvature of the Earth, so signal range is sharply limited. Microwave relay towers could solve the problem, but a complete network of repeater towers would be extremely expensive. The satellite provides an obstruction-free relay station in space.

  16. Radio stars.

    PubMed

    Hjellming, R M; Wade, C M

    1971-09-17

    Up to the present time six classes of radio stars have been established. The signals are almost always very faint and drastically variable. Hence their discovery has owed as much to serendipity as to the highly sophisticated equipment and techniques that have been used. When the variations are regular, as with the pulsars, this characteristic can be exploited very successfully in the search for new objects as well as in the detailed study of those that are already known. The detection of the most erratically variable radio stars, the flare stars and the x-ray stars, is primarily a matter of luck and patience. In the case of the novas, one at least knows where and oughly when to look for radio emission. A very sensitive interferometer is clearly the best instrument to use in the initial detection of a radio star. The fact that weak background sources are frequently present makes it essential to prove that the position of a radio source agrees with that of a star to within a few arc seconds. The potential of radio astronomy for the study of radio stars will not be realized until more powerful instruments than those that are available today can be utilized. So far, we have been able to see only the most luminous of the radio stars. PMID:17836594

  17. The Mexican national satellite system

    NASA Astrophysics Data System (ADS)

    Sanchez Ruiz, M. E.; Briskman, R. D.

    1983-10-01

    The satellites, tracking, telemetry, command, and monitoring facilities, and the earth station complex for the Mexican national satellite system, Morelos, are described. The spacecraft are intended to provide educational television, rural telephony, data transmission, and business and industrial services. Scheduled for 1985 launch, the satellites will be placed in GEO and use the C and Ku bands with 12 narrow band and six wideband transponders. Spin-stabilized and solar cell powered, the functional mass will be 666 kg, including propellant. The solar panels will provide 940 W of power and 830 W will be available from NiCd batteries during eclipse conditions. The earth station will be located at Iztapalapa, which will have a 12 m antenna, redundant uplink and downlink radios, and command and ranging equipment. Back-up capability will be provided by a station at Tulancingo. Ku band and C band stations are in planning.

  18. Corporations Can Be Decent.

    ERIC Educational Resources Information Center

    Heiskell, Andrew

    1981-01-01

    The "third stage" of corporate development, in which business firms seek ways to serve society, is described. In 1980, corporations became the largest single identifiable source of giving in the United States. (Author/MLW)

  19. Essays on corporate bonds

    E-print Network

    Bao, Jack (Jack C.)

    2009-01-01

    This thesis consists of three empirical essays on corporate bonds, examining the role of both credit risk and liquidity. In the first chapter, I test the ability of structural models of default to price corporate bonds in ...

  20. Corporate sustainability assessment methodology

    E-print Network

    Pinchuk, Natallia

    2011-01-01

    Sustainability is a vague concept specifically in the context of a corporate world. There are numerous definitions for corporate sustainability and just as many ways of evaluating it. This work attempts to define, structure ...

  1. Institutional Investors, Corporate Ownership and Corporate Governance

    Microsoft Academic Search

    Stuart L. Gillan; Laura T. Starks

    2002-01-01

    We examine the role of institutional investors in financial markets and in corporate governance. In many countries, institutional investors have become the predominant players in financial markets and their influence worldwide is growing, chiefly due to the privatization and development of pension fund systems. Moreover, foreign institutional investors are becoming a significant presence, bringing their trading habits and corporate governance

  2. Centriolar Satellites

    PubMed Central

    Kubo, Akiharu; Sasaki, Hiroyuki; Yuba-Kubo, Akiko; Tsukita, Shoichiro; Shiina, Nobuyuki

    1999-01-01

    We identified Xenopus pericentriolar material-1 (PCM-1), which had been reported to constitute pericentriolar material, cloned its cDNA, and generated a specific pAb against this molecule. Immunolabeling revealed that PCM-1 was not a pericentriolar material protein, but a specific component of centriolar satellites, morphologically characterized as electron-dense granules, ?70–100 nm in diameter, scattered around centrosomes. Using a GFP fusion protein with PCM-1, we found that PCM-1–containing centriolar satellites moved along microtubules toward their minus ends, i.e., toward centrosomes, in live cells, as well as in vitro reconstituted asters. These findings defined centriolar satellites at the molecular level, and explained their pericentriolar localization. Next, to understand the relationship between centriolar satellites and centriolar replication, we examined the expression and subcellular localization of PCM-1 in ciliated epithelial cells during ciliogenesis. When ciliogenesis was induced in mouse nasal respiratory epithelial cells, PCM-1 immunofluorescence was markedly elevated at the apical cytoplasm. At the electron microscopic level, anti–PCM-1 pAb exclusively labeled fibrous granules, but not deuterosomes, both of which have been suggested to play central roles in centriolar replication in ciliogenesis. These findings suggested that centriolar satellites and fibrous granules are identical novel nonmembranous organelles containing PCM-1, which may play some important role(s) in centriolar replication. PMID:10579718

  3. Ionospheric effects upon a satellite navigation system at Mars

    Microsoft Academic Search

    Michael Mendillo; Xiaoqing Pi; Steven Smith; Carlos Martinis; Jody Wilson; David Hinson

    2004-01-01

    Trans-ionospheric radio propagation effects resulting in ranging errors are examined for a potential orbital network of communications and navigational satellites at Mars. Using recent results from the radio science experiment on board the Mars Global Surveyor (MGS) spacecraft and a photochemical model of Mars' ionosphere, we study the total electron content (TEC) at Mars to investigate how its latitude, local

  4. European Corporate Sustainability Framework

    Microsoft Academic Search

    Marcel Van Marrewijk; Teun W. Hardjono

    abstract The European Corporate Sustainability Framework (ECSF) is a new generation management framework, aimed to meet increased corporate complexity and support corporate transformation towards more sustainable ways of doing business. It is a multi-layer, integral business framework with an analytical, contextual, situational and dynamic dimension. Analytically, the framework is structured according to four focus points - the constitutional, conceptual, behavioural

  5. ENGAGING UNH Corporate Resources

    E-print Network

    New Hampshire, University of

    .Sciences.and.Engineering Materials.Sciences Social.and.Health.Sciences Sustainability.Programs TABLE OF CONTENTS #12;CorporateENGAGING UNH Corporate Resources www.unh.edu/corporateresources Strategic relationships to connect the University's educational, research, and outreach mission with your corporate or company goals 2007 Connecting

  6. Cosmic Radio Series Brings Celestial Science Down to Earth

    NASA Astrophysics Data System (ADS)

    2008-01-01

    A new series of short radio programs designed to bring the space-age science of radio astronomy down to Earth is being launched by the National Radio Astronomy Observatory (NRAO) and Allegheny Mountain Radio. The series, called Cosmic Radio, covers topics ranging from exciting recent scientific discoveries to how radio telescopes help explore the Universe, to the fascinating history of radio astronomy. "The discoveries and history of radio astronomy include many exciting stories, and Cosmic Radio will bring those stories to listeners across the country," said Sue Ann Heatherly, the NRAO Education Officer in Green Bank, West Virginia, and co-producer of the series. Gibbs Kinderman, of Allegheny Mountain Radio, the other co-producer, added, "The subject matter is fascinating, and we did a lot of work making the complex topics comprehensible even to a science dummy like me." Cosmic Radio includes 26 self-contained radio programs, each 2.5 minutes in length, explaining some aspect of radio astronomy. Produced with funding from the Corporation for Public Broadcasting, the programs are available to all radio stations at no cost. The programs have been provided on CD to more than 500 NPR-affiliated stations, and will be available through a Web site that will be updated with a new program each week.

  7. Corporate/Foundation Relations CORPORATE AND FOUNDATION RELATIONS The Offices of Corporate and

    E-print Network

    Mather, Patrick T.

    Corporate/Foundation Relations - 1 - CORPORATE AND FOUNDATION RELATIONS The Offices of Corporate and Foundation Relations (CR, FR) are responsible for coordinating with OSP on applications to key University development and institutional advancement prospects. Applying to Foundations or Corporations. Faculty

  8. Satellite systems for Latin American telecommunication requirements

    NASA Astrophysics Data System (ADS)

    Elizondo, Eduardo L.

    Aspects of satellite telecommunications systems of interest to Latin America are discussed. Presently existing systems are described, including both state-run and international services. Services planned for the region are examined, including Geostar, a service that provides satellite radio determination and message services, a system which will provide a high-capacity digital voice and data service for airlines, and direct broadcast satellites. Applications of these systems in education, rural telephony, data transmission, news services, publishing, emergency communications, and mobile communications are addressed.

  9. 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.

  10. Satellite data

    NASA Technical Reports Server (NTRS)

    Njoku, E. G.

    1983-01-01

    Three satellite SST data sets were analyzed, all derived from the Scanning Multichannel Microwave Radiometer (SMMR) on the Nimbus-7 satellite. The SMMR is a ten-channel instrument flown also on the SEASAT satellite (now defunct) and was designed to measure SST in addition to other oceanographic and meteorological parameters. The three SMMR data sets were referred to as SMMR-I, -II, and -III. SMMR-I and -II were produced by T. Wilheit and A. Milman, SMMR-II being an updated and refined version of SMMR-I. A description of the algorithms used is provided. SMMR-III was provided by C. Prabhakara and was obtained by a different retrieval approach from the others. For consistency with the file code conventions and to avoid confusion, SMMRs I, II, and III were renamed SMMR-A, SMMR-D, and SMMR-C, respectively.

  11. Radio Holographic and Wavelet Analyses of Radio Occultation Data

    NASA Astrophysics Data System (ADS)

    Benzon, H.-H.; Lauritsen, K. B.

    We discuss the radio occultation technique which enables one to obtain informa- tion about key atmospheric parameters. The basic idea is a measurement of the GPS (Global Positioning System) radio signals by a satellite in a low-earth orbit (LEO). The bending of the signals then contain information about atmospheric parameters such as refractivity, temperature, pressure, and water vapour. The radio holographic technique is based on the window Fourier transform of the mea- sured time signal. The Fourier transform is calculated in a small aperture that moves along the satellite trajectory. Carrying out this analysis yields a two-dimensional spec- trum of the measured signal where the maxima can be interpreted as rays. Strong water vapour gradients may give rise to multipath phenomena and this is seen in the spec- trum as multiple maxima for a given aperture. We analyze simulated data and compare radio holographic results with results from a method based on a wavelet transform which also yields a two-dimensional representation of the measured field. We discuss whether the wavelet analysis can result in improved estimates for the location of the maxima in the spectrum.

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

    Microsoft Academic Search

    Yoshitsugu Yasui

    2008-01-01

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

  13. 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.

  14. Remote Student Access to Education via Satellite Delivery.

    ERIC Educational Resources Information Center

    Boylan, Colin; Wallace, Andrew; Richmond, Wayne

    2000-01-01

    In response to the expense and unreliability of radio and telephone communications, the New South Wales (Australia) Department of Education and Training undertook a trial of satellite technology to deliver interactive lessons to elementary students in remote areas. The Gilat satellite system developed in Israel is described, including equipment,…

  15. Satellite Measurements ,of Low-Energy Electrons in the

    Microsoft Academic Search

    R. D. SHARP; J. E. EVANS; W. L. IMHOF; R. G. JOHNSON; J. B. REAGAN; R. V. SMITH

    1964-01-01

    Particle flux measurements and radio and optical measurements on auroras were made concurrently with detectors aboard a polar orbiting satellite near the northern auroral zone. The incident particle energy deposition was measured in two shielded plastic scintillators with electron thresholds of 2 and 28 key. Data were obtained for six satellite passes over the auroral zone, and for parts of

  16. Multiservice on-board switching for mobile satellite communications

    Microsoft Academic Search

    L. Bella

    1988-01-01

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

  17. Approved Module Information for EE3RSY, 2014/5 Module Title/Name: Radio Systems and Personal

    E-print Network

    Neirotti, Juan Pablo

    and satellite communications. Module Learning Outcomes: Knowledge and Understanding: * mobile communication Communications Systems: Introduce practical radio communications systems such as satellite and mobile Communications Systems Module Code: EE3RSY School: Engineering and Applied Science Module Type: Standard Module

  18. Radio Pulsars

    NASA Astrophysics Data System (ADS)

    Beskin, V. S.; Chernov, S. V.; Gwinn, C. R.; Tchekhovskoy, A. A.

    2015-06-01

    Almost 50 years after radio pulsars were discovered in 1967, our understanding of these objects remains incomplete. On the one hand, within a few years it became clear that neutron star rotation gives rise to the extremely stable sequence of radio pulses, that the kinetic energy of rotation provides the reservoir of energy, and that electromagnetic fields are the braking mechanism. On the other hand, no consensus regarding the mechanism of coherent radio emission or the conversion of electromagnetic energy to particle energy yet exists. In this review, we report on three aspects of pulsar structure that have seen recent progress: the self-consistent theory of the magnetosphere of an oblique magnetic rotator; the location, geometry, and optics of radio emission; and evolution of the angle between spin and magnetic axes. These allow us to take the next step in understanding the physical nature of the pulsar activity.

  19. Radio Pulsars

    E-print Network

    Beskin, V S; Gwinn, C R; Tchekhovskoy, A

    2015-01-01

    Almost 50 years after radio pulsars were discovered in 1967, our understanding of these objects remains incomplete. On the one hand, within a few years it became clear that neutron star rotation gives rise to the extremely stable sequence of radio pulses, that the kinetic energy of rotation provides the reservoir of energy, and that electromagnetic fields are the braking mechanism. On the other hand, no consensus regarding the mechanism of coherent radio emission or the conversion of electromagnetic energy to particle energy yet exists. In this review, we report on three aspects of pulsar structure that have seen recent progress: the self-consistent theory of the magnetosphere of an oblique magnetic rotator; the location, geometry, and optics of radio emission; and evolution of the angle between spin and magnetic axes. These allow us to take the next step in understanding the physical nature of the pulsar activity.

  20. Satellite Winds

    NSDL National Science Digital Library

    In this online, interactive module, students learn about the using successive satellite observations of clouds to determine wind direction and speed. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.

  1. Telecommunications satellites for developing countries - Extension of satellite use to rural areas

    NASA Astrophysics Data System (ADS)

    Pinglier, A.

    1980-02-01

    The potential of telecommunications satellites to improve communications in developing nations, particularly the rural areas, is considered. Requirements for improved telephone, television and radio service in developing nations are indicated, and it is argued that satellites would provide one of the most efficient means of developing networks for telephony, television and radio both for intercity trunk routes and for rural areas. The forms such satellite systems could take for rural telephony and direct, semidirect and redistributed television broadcasting are examined, and an approach to the integration of telephone and television services is proposed. Telephony and television capacity requirements for a typical sub-Saharan country are estimated, and the financial aspects of the systems are considered. It is concluded that satellites can considerably improve the general communications situation in many developing nations, giving vast rural areas access to telecommunications for the first time and with comparatively low funding requirements.

  2. Radio Tagged Adult Female Walrus on Ice Floe

    USGS Multimedia Gallery

    Adult female walrus on ice floe photographed shortly after receiving a behavior monitoring satellite-linked radio tag from USGS researchers.  Data acquired from such radio-tags are providing insights on the distribution and behavior of Pacific walruses during a time when their summer sea ice h...

  3. New Technology in Radio: A Macro- and Micro- View.

    ERIC Educational Resources Information Center

    Fletcher, James E.

    Recent developments in radio technology are reflected in increases in the number of stations available to listeners in more communities, improvements in audio technology, increased use of satellite interconnection, and extensive automation; however, too little of the impact of these continuing changes has been felt by radio management and…

  4. MARS IONOSPHERE STUDIES USING THE MGS RADIO SCIENCE EXPERIMENT

    E-print Network

    Withers, Paul

    MARS IONOSPHERE STUDIES USING THE MGS RADIO SCIENCE EXPERIMENT M. Mendillo and P. Withers Center of the Mars Global Surveyor (MGS) satellite, ionospheric science at Mars depended upon a total of 433 Radio Science (RS) experiment active at Mars since 1997, the MGS ionospheric database now includes

  5. Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking

    E-print Network

    Wichmann, Felix

    be also based on other radio access bearer techniques as, for example, single frequency networks of DVB¨at Berlin, Einsteinufer 17, 10587 Berlin, Germany 3 Ericsson Research, Mobile Multimedia Networks, EricssonHindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume

  6. A scalable range radio-communication interfacing for embedded systems

    Microsoft Academic Search

    T. Kochanski; R. Niski; A. Rucinski; J. Zurek

    2008-01-01

    This paper describes the radio-communications ldquostate-of-the-artrdquo and ldquostate-of-the-practicerdquo for interfacing nodes in an ambient intelligence network. We also discuss the role of software defined hardware for software defined radios that form the radio-communication interface for ambient intelligence networks. Nodes must be capable of communication over at least one medium from Wibree-like (Bluetooth) to broadband satellite, preferably with flexible range and

  7. A new digital land mobile satellite system

    NASA Astrophysics Data System (ADS)

    Schneider, Philip

    A description is given of the different digital services planned to be carried over existing and planned mobile satellite systems. These systems are then compared with analog services in terms of bandwidth and power efficiency. This comparison provides the rationale for the establishment of a digital land mobile satellite service (DLMSS) to use frequencies that are currently available but not yet assigned to a domestic mobile satellite system in the United States. The focus here is on the expected advantages of digital transmission techniques in accommodating additional mobile satellite systems in this portion of the spectrum, and how such techniques can fully satisfy voice, data and facsimile mobile communications requirements in a cost effective manner. A description is given of the system architecture of the DMLSS service proposed by the Geostar Messaging Corporation (GMC) and the market potential of DLMSS.

  8. A School Radio Telescope for Two Metres

    ERIC Educational Resources Information Center

    Codling, J. C.

    1973-01-01

    Discusses the arrangement, specifications, and operation of a setup designed for use as a student project to record radio storms, continuous level of the quiet sun, and scientific satellites operating near the amateur 2-m band. Included is an example of records of solar activity during 1968-73. (CC)

  9. Virtual Satellite

    NASA Technical Reports Server (NTRS)

    Hammrs, Stephan R.

    2008-01-01

    Virtual Satellite (VirtualSat) is a computer program that creates an environment that facilitates the development, verification, and validation of flight software for a single spacecraft or for multiple spacecraft flying in formation. In this environment, enhanced functionality and autonomy of navigation, guidance, and control systems of a spacecraft are provided by a virtual satellite that is, a computational model that simulates the dynamic behavior of the spacecraft. Within this environment, it is possible to execute any associated software, the development of which could benefit from knowledge of, and possible interaction (typically, exchange of data) with, the virtual satellite. Examples of associated software include programs for simulating spacecraft power and thermal- management systems. This environment is independent of the flight hardware that will eventually host the flight software, making it possible to develop the software simultaneously with, or even before, the hardware is delivered. Optionally, by use of interfaces included in VirtualSat, hardware can be used instead of simulated. The flight software, coded in the C or C++ programming language, is compilable and loadable into VirtualSat without any special modifications. Thus, VirtualSat can serve as a relatively inexpensive software test-bed for development test, integration, and post-launch maintenance of spacecraft flight software.

  10. Radio astronomy

    NASA Technical Reports Server (NTRS)

    Kellermann, Kenneth I.; Heeschen, David; Backer, Donald C.; Cohen, Marshall H.; Davis, Michael; Depater, Imke; Deyoung, David; Dulk, George A.; Fisher, J. R.; Goss, W. Miller

    1991-01-01

    The following subject areas are covered: (1) scientific opportunities (millimeter and sub-millimeter wavelength astronomy; meter to hectometer astronomy; the Sun, stars, pulsars, interstellar masers, and extrasolar planets; the planets, asteroids, and comets; radio galaxies, quasars, and cosmology; and challenges for radio astronomy in the 1990's); (2) recommendations for new facilities (the millimeter arrays, medium scale instruments, and small-scale projects); (3) continuing activities and maintenance, upgrading of telescopes and instrumentation; (4) long range programs and technology development; and (5) social, political, and organizational considerations.

  11. Battery voltage variations and radio transmitter temperatures of the small spacecraft

    NASA Astrophysics Data System (ADS)

    Shakhparonov, V. M.; Karagioz, O. V.

    2014-05-01

    Diurnal variations of the storage battery voltages as well as temperatures of the radio transmitters on board the small satellite "Universitetsky" have been revealed. Double-humped dependences have been found, related to changes of the micro satellite position relative to the Earth and the Sun and to the on-board satellite systems' operation.

  12. Corporate Energy Management Process 

    E-print Network

    Geiger, T.

    2013-01-01

    Corporation?s capital and expense projects which consume or generate energy ? Regional platform for global energy expert group Management Commitment BASF Corporate Energy Management Department ESL-IE-13-05-25 Proceedings of the Thrity-Fifth Industrial... leads to Success Energy and Process Optimization Workshops 3 ? 4 year cycle ESL-IE-13-05-25 Proceedings of the Thrity-Fifth Industrial Energy Technology Conference New Orleans, LA. May 21-24, 2013 Best Practice and Technology sharing ? Energy...

  13. Domestic mobile satellite systems in North America

    NASA Technical Reports Server (NTRS)

    Wachira, Muya

    1990-01-01

    Telest Mobile Inc. (TMI) and the American Mobile Satellite Corporation (AMSC) are authorized to provide mobile satellite services (MSS) in Canada and the United States respectively. They are developing compatible systems and are undertaking joint specification and procurement of spacecraft and ground segment with the aim of operational systems by late 1993. Early entry (phase 1) mobile data services are offered in 1990 using space segment capacity leased from Inmarsat. Here, an overview is given of these domestic MSS with an emphasis on the TMI component of the MSAT systen.

  14. Ku-band satellite digital transmission systems

    NASA Astrophysics Data System (ADS)

    McGann, W. E.

    1985-09-01

    A nation-wide data communications service is being placed in service by a major telecommunications carrier. This service will rely on a satellite network being provided and installed by Harris Satellite Communications Corporation. The network supports information data rates from 56 kb/s to 2.048 Mb/s. This data communications network has been architectured to include a number of innovative monitor and control functions, up-link power control, modular equipment shelter design and a modular antenna/feed subsystem. This paper will detail this application.

  15. 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.

  16. Satellite-to-satellite tracking orbit determination

    Microsoft Academic Search

    B. T. Fang

    1978-01-01

    In the 1980's, low-earth-satellite orbits will be determined from one-way or relayed range and range-rate measurements to high-altitude orbiting spacecraft such as the two geo-synchronous satellites in the NASA Tracking and Data Relay Satellite System (TDRSS) and the 24 twelve-hour period, 63 deg inclination spacecraft in the DOD Global Positioning System (GPS). In this study, error analysis methods for satellite-to-satellite

  17. Corporate states or corporate citizens? Chess between corporations, states and citizens with sustainable development at stake

    Microsoft Academic Search

    Tarja Ketola

    2011-01-01

    The economies of large states are run by large corporations. Smaller states have become single corporate states. Yet companies claim to be corporate citizens, talking about their responsibilities towards society. States used to have lots of power and responsibility; citizens little power and responsibility. Are corporations breaking this bond of balance by taking lots of power as corporate states but

  18. Redesigning the corporate centre

    Microsoft Academic Search

    Michael Goold; David Pettifer; David Young

    2001-01-01

    The authors report the results of a recent large study of corporate centre transformation: a question which is often an early priority when a new chief executive takes office. This article summarises their approach to corporate centre design which maximises value creation.Recognising that there are differences in the pattern of headquarters between countries, the authors base their recommendation for a

  19. Bottle Rock Power Corporation

    E-print Network

    Bottle Rock Power Corporation 1275 4th Street, No. 105 Phone: 707.541.0976 Santa Rosa, CA 95404 Fax 1516 9th Street, MS-2000 Sacramento, CA 95814-5512 RE: Bottle Rock Power Plant (79-AFC-4C) Petition for Extending Environmental Monitoring Program Dear Ms. Tronaas: The Bottle Rock Power Corporation (BRPC

  20. International Corporate Governance

    Microsoft Academic Search

    Diane K. Denis; John J. McConnell

    2002-01-01

    We survey two generations of research on corporate governance systems around the world, concentrating on countries other than the United States. The first generation of international corporate governance research is patterned after the US research that precedes it. These studies examine individual governance mechanisms - particularly board composition and equity ownership - in individual countries. The second generation of international

  1. Corporal Punishment Revisited.

    ERIC Educational Resources Information Center

    Wilson, John

    2002-01-01

    Lists arguments for using corporal punishment in educational institutions and considers some advantages of its use. Asks when it should be used, who should be empowered to administer it, and why there are increasingly strong feelings against corporal punishment in some societies while others continue to use it. (BT)

  2. Corporal Punishment Handbook.

    ERIC Educational Resources Information Center

    Maurer, Adah

    This handbook describes the use of corporal punishment, attitudes towards it, and alternatives to it. Topics covered include: (1) a definition of corporal punishment; (2) descriptions and examples of different types; (3) a brief history of its use in schools and society; (4) arguments in favor of its use; (5) arguments for abolition; (6)…

  3. Corporate Environmental Responsibility

    Microsoft Academic Search

    Joe DesJardins

    1998-01-01

    This paper offers directions for the continuing dialogue between business ethicists and environmental philosophers. I argue that a theory of corporate social responsibility must be consistent with, if not derived from, a model of sustainable economics rather than the prevailing neoclassical model of market economics. I use environmental examples to critique both classical and neoclassical models of corporate social responsibility

  4. Measuring Corporate Sustainability

    Microsoft Academic Search

    Giles Atkinson; Tannis Hett; Jodi Newcombe

    2000-01-01

    Although sustainable development has been interpreted primarily as a national (or global) goal, there is increasing discussion of the 'sustainable city', the 'sustainable sector' and the 'sustainable business'. In this paper, the notion of corporate sustainability is explored and developed. We argue that one of the keys to understanding corporate sustainability is full cost accounting, that is, valuing pollution in

  5. InProc.oftheTheFullyNetworkedCarWorkshop,GenevaInternationalMotorShow,Geneva,Switzerland,March34,2010. Opportunistic Vehicular Networks by Satellite Links

    E-print Network

    applications, based on satellite communication links (i.e., LEO/MEO satellite constellations). In such scenario,2010. Opportunistic Vehicular Networks by Satellite Links for Safety Applications A.M. Vegni1 , C. Vegni2 , and T, Boston, MA tdcl@ bu.edu Satellite radio is one of a complementary set of network connectivity

  6. Propagation considerations in the American Mobile Satellite system design

    NASA Technical Reports Server (NTRS)

    Kittiver, Charles; Sigler, Charles E., Jr.

    1993-01-01

    An overview of the American Mobile Satellite Corporation (AMSC) mobile satellite services (MSS) system with special emphasis given to the propagation issues that were considered in the design is presented. The aspects of the voice codec design that effect system performance in a shadowed environment are discussed. The strategies for overcoming Ku-Band rain fades in the uplink and downlink paths of the gateway station are presented. A land mobile propagation study that has both measurement and simulation activities is described.

  7. Space Telecommunications Radio System STRS Cognitive Radio

    NASA Technical Reports Server (NTRS)

    Briones, Janette C.; Handler, Louis M.

    2013-01-01

    Radios today are evolving from awareness toward cognition. A software defined radio (SDR) provides the most capability for integrating autonomic decision making ability and allows the incremental evolution toward a cognitive radio. This cognitive radio technology will impact NASA space communications in areas such as spectrum utilization, interoperability, network operations, and radio resource management over a wide range of operating conditions. NASAs cognitive radio will build upon the infrastructure being developed by Space Telecommunication Radio System (STRS) SDR technology. This paper explores the feasibility of inserting cognitive capabilities in the NASA STRS architecture and the interfaces between the cognitive engine and the STRS radio. The STRS architecture defines methods that can inform the cognitive engine about the radio environment so that the cognitive engine can learn autonomously from experience, and take appropriate actions to adapt the radio operating characteristics and optimize performance.

  8. 8 LINCOLN LABORATORY JOURNAL n VOLUME 21, NUMBER 1, 2014 InsIghts Into the UnIverse: Astronomy wIth hAystAck's rAdIo telescope

    E-print Network

    Williams, Brian C.

    wIth hAystAck's rAdIo telescope Insights into the Universe: Astronomy with Haystack's Radio Telescope game-changing tech- nology for radio science, and to apply it to the study of our planet, its space projects. The observatory is operated under an agreement with the Northeast Radio Observatory Corporation

  9. Radio-electronic equipment

    NASA Astrophysics Data System (ADS)

    Boldin, Viktor A.; Gorgonov, Gennadii I.; Konovalov, Viktor D.; Kurilov, N. N.; Levonchuk, V. V.

    The fundamentals of radio electronics are first elaborated, with attention given to the principles of circuits and signals, semiconductor devices, computing techniques, radio transmitters and receivers, and wave propagation. The principles of operation of onboard radio-electronic devices are then described, with emphasis on radio communication systems, radar systems, radio navigation systems, radio control systems, and electronic countermeasures. The maintenance of radio-electronic devices is also discussed.

  10. Satellites in Education.

    ERIC Educational Resources Information Center

    Jones, David

    1988-01-01

    Describes the methods and materials used to obtain satellite pictures from weather satellites. Discusses possible physics lessons which can be done using this equipment including orbital mechanics, and how the satellite works. (CW)

  11. Corporate awakening - why (some) corporations embrace public-private partnerships

    Microsoft Academic Search

    Julie LaFrance; Martin Lehmann

    2005-01-01

    Predominantly since the 1992 Rio Summit, corporations have been increasingly pur- suing partnerships with public institutions including governments, international orga- nizations and NGOs that aim to contribute to sustainable development activities. Partnerships have become more common as corporations react to mounting pres- sure from corporate stakeholders, civil society and government on the responsible nature of their business practices. The corporate

  12. Corporate Social Responsibility, Corporate Governance and Auditing in Japan

    Microsoft Academic Search

    Ryuuichiro KURIHAMA

    2005-01-01

    This paper clarifies the issues and future challenges that Japanese corporations are facing through discussion of Corporate Social Responsibility (CSR) in Japan. And it also clarifies the relationship between CSR, corporate governance, and auditing in Japan while it examines the concept of auditing as corporate auditing. In recent years, we see a growing trend toward discussion of CSR. However, CSR

  13. Corporate identity and corporate communications: creating a competitive advantage

    Microsoft Academic Search

    John M. T. Balmer; Edmund R. Gray

    2000-01-01

    Recent environmental trends are forcing senior managers to give greater import to corporate identity and corporate communications. They are discovering that conventional methods of redressing identity problems are becoming progressively less effective because, in our opinion, the traditional focus has viewed corporate identity and corporate communications as functional rather than as strategic. We suggest a much broadened view that looks

  14. Corporate identity and corporate communications: creating a competitive advantage

    Microsoft Academic Search

    John M. T. Balmer; Edmund R. Gray

    1999-01-01

    Recent environmental trends are forcing senior managers to give greater import to corporate identity and corporate communications. They are discovering that conventional methods of redressing identity problems are becoming progressively less effective because, in our opinion, the traditional focus has viewed corporate identity and corporate communication as functional rather than as strategic. We suggest a much broadened view that looks

  15. Corporate identity and corporate communications: the antidote to merger madness

    Microsoft Academic Search

    John M. T. Balmer; Keith Dinnie

    1999-01-01

    This article examines the potential relevance of corporate identity and corporate communication to the merger and acquisition process. Recent studies indicate that around 50 per cent of all mergers failed to produce the synergistic benefits that were expected of them. The authors argue that this failure rate may be attributable to the neglect of corporate identity and corporate communication issues

  16. IMAGE Satellite Scaling

    NSDL National Science Digital Library

    2012-08-03

    This is an activity about satellite size. Learners will calculate the volume of the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite, the first satellite mission to image the Earth's magnetosphere. They will then determine the effect of doubling and tripling the satellite dimensions on the satellite's mass and cost. This is the first activity in the Solar Storms and You: Exploring Satellite Design educator guide.

  17. Petite Amateur Navy Satellite (PANSAT)

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The subsystem and structural design of the Naval Post Graduate School's Petite Amateur Navy Satellite (PANSAT) is described. The objectives of PANSAT are: (1) to provide an ideal educational tool for officer students; (2) to provide digital store-and-forward communications, or packet radio, for the amateur radio community; and (3) to provide a low-cost space-based platform for small experiments. PANSAT will be launched from the Shuttle at a nominal altitude of 200 nmi. and an inclination of at least 37 deg. Since there is no attitude control, eight dipole whip antennas will be used to provide isotropic ground coverage for communications. FM digital communications will be used with up-link and down-link on a single frequency in the amateur band of 144 to 146 MHz or 437 to 438 MHz. The satellite's communications subsystem, data processor and sequencer, power subsystem, structure subsystem, and experiment payload are described. The major experiment being considered will test the on-orbit annealing of radiation damaged solar cells.

  18. Financial Statistics of CPB-Qualified Public Radio Stations: Fiscal Year 1970.

    ERIC Educational Resources Information Center

    Pedone, Ronald J.; And Others

    Financial statistics for fiscal year 1970 are reported for 91 public radio stations which meet the requirements for CPB (Corporation for Public Broadcasting) general support grants. The statistics are for the aggregate United States, classified by geographic regions and types of licensees. Total income for radio operations for the fiscal year…

  19. "SpaceCam": Legal Issues in the Use of Remote-Sensing Satellites for News Gathering.

    ERIC Educational Resources Information Center

    Smith, William E.

    News media representatives foresee a growing use of remote-sensing satellites to gather data, including data that could be used to check government claims about military and other activities occurring anywhere on the planet. The satellite technology is developing rapidly, and several nations and private corporations are involved in separate…

  20. Satellite observations of transionospheric pulse pairs

    SciTech Connect

    Holden, D.N.; Munson, C.P.; Devenport, J.C. [Los Alamos National Lab., NM (United States)] [Los Alamos National Lab., NM (United States)

    1995-04-15

    The BLACKBEARD payload aboard the ALEXIS satellite has been making broadband observations in the VHF band of the radio spectrum. Since November of 1993 several hundred unusual signals have been recorded. The peculiar nature of these bursts of radio noise is that they have a duration of approximately 10 {mu}sec, are typically 20 to 40 dB brighter than the average background, and occur in pairs separated by approximately 50 {mu}sec. The authors have dubbed these emissions TransIonospheric Pulse Pairs, or TIPP events. They do not know what the source of these emissions is, but the dispersion of these signals is consistent with an origin at or near the earth`s surface. The satellite field of view and time of day when TIPP events are generally detected are consistent with regions of thunderstorm activity such as south-central Africa or Indonesia. 4 refs., 5 figs.

  1. Integration and corporate investment

    E-print Network

    Ozbas, Oguzhan, 1971-

    2002-01-01

    This thesis consists of three chapters that broadly investigates, theoretically and empirically, the effect of firm boundaries and organizational processes on internal resource allocation and corporate investment. In the ...

  2. CORPORATE GOVERNANCE CURTIN UNIVERSITY

    E-print Network

    CORPORATE GOVERNANCE STATEMENT CURTIN UNIVERSITY 25 September 2013 (Version 1.1) Curtin University................................................................................................................5 2. CURTIN UNIVERSITY'S FRAMEWORK FOR INSTRUMENTS OF GOVERNANCE.5 2.1 Introduction.1 Council as the governing authority

  3. CORPORATE GOVERNANCE CURTIN UNIVERSITY

    E-print Network

    CORPORATE GOVERNANCE STATEMENT CURTIN UNIVERSITY 26 September 2012 (Version 1.0) Curtin University................................................................................................................5 2. CURTIN UNIVERSITY'S FRAMEWORK FOR INSTRUMENTS OF GOVERNANCE.5 2.1 Introduction.1 Council as the governing authority

  4. Antecedents of corporate volunteerism 

    E-print Network

    Henning, Jaime Blaine

    2009-05-15

    with volunteering in general, few studies have examined variables beyond simple demographics, and fewer still have examined antecedents of corporate volunteering. In the current study, the theory of planned behavior, functional motives for volunteering...

  5. Encyclopedia of Corporate Governance

    NSDL National Science Digital Library

    Encyclopedia of Corporate Governance, or encycogov for short, is created and maintained by Henrik Mathiesen, a PhD candidate at the Department of International Economics and Management at the Copenhagen Business School. Content on the site is divided into two sections: Specific Topics and General Topics. Topics in both sections begin with a paragraph explaining the overarching definition of the principle, and link to a variety of tables, "exhibitions," and models that further illustrate the definition. For example, the Bankruptcy Systems section begins with the definition and is followed up by two tables: "Effects of bankruptcy systems on corporate performance and other kinds of institutions of relevance for corporate governance" and "International corporate governance- Tentative characterizations of legal and empirical state of large firm bankruptcy systems in various countries as of 1980-95: 1) Developing countries. 2)Germany. 3) Japan. 4) Anglo-American countries. 5) Denmark." Also included on the site are references and site users information.

  6. The Rise of All-Band All-Mode Radio Steve Ellingson and S.M. Shajedul Hasan

    E-print Network

    Ellingson, Steven W.

    communications, cellular and satellite communications, and wireless local area networks (WLAN). At the same time. In this approach, disparate radio networks are integrated through the use of radios that are combined back. For decades mobile radios have been based on superheterodyne architecture, in which frequency selectivity

  7. Orbit Modelling for Satellites Using the NASA Prediction Bulletins

    NASA Technical Reports Server (NTRS)

    Bonavito, N. L.; Koch, D. W.; Maslyar, G. A.; Foreman, J. C.

    1976-01-01

    For some satellites the NASA Prediction Bulletins are the only means available to the general user for obtaining orbital information. A computational interface between the information given in the NASA Prediction Bulletins and standard orbit determination programs is provided. Such an interface is necessary to obtain accurate orbit predictions. The theoretical considerations and their computational verification in this interface modelling are presented. This analysis was performed in conjunction with satellite aided search and rescue position location experiments where accurate orbits of the Amateur Satellite Corporation (AMSAT) OSCAR-6 and OSCAR-7 spacecraft are a prerequisite.

  8. Radio tracking system

    NASA Technical Reports Server (NTRS)

    Breidenthal, J. C.; Komarek, T. A.

    1982-01-01

    The principles and techniques of deep space radio tracking are described along with the uses of tracking data in navigation and radio science. Emphasis is placed on the measurement functions of radio tracking.

  9. What is Radio Astronomy?

    NSDL National Science Digital Library

    This website contains information on radio astronomy, the NRAO, how telescopes work, the history and discovery of radio astronomy, and the radio communication process. This website has activites like "Make your own Radio Image", and visual aids on topics such as: free-free emission, spectral lines, synchrotron emission, masers, and how radio communication works. The site is also a resource for blackbody radiation, the Cosmic Microwave Backround, and the mechanisms of radio wave emission.

  10. Low cost satellite land mobile service for nationwide applications

    NASA Technical Reports Server (NTRS)

    Weiss, J. A.

    1978-01-01

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

  11. Federal Communications Commission US311 Radio astronomy observations may be made in the bands 13501400 MHz and 49504990 MHz

    E-print Network

    Bower, Geoffrey

    in the mobile­satellite service. Communications of mobile ­satellite system stations not participating in the GMDSS. Account shall be taken of the priority of safety­related communications in the mobile­satelliteFederal Communications Commission 162 US311 Radio astronomy observations may be made in the bands

  12. Learning radio astronomy by doing radio astronomy

    NASA Astrophysics Data System (ADS)

    Vaquerizo Gallego, J. A.

    2011-11-01

    PARTNeR (Proyecto Académico con el Radio Telescopio de NASA en Robledo, Academic Project with the NASA Radio Telescope at Robledo) is an educational program that allows high school and undergraduate students to control a 34 meter radio telescope and conduct radio astronomical observations via the internet. High-school teachers who join the project take a course to learn about the science of radio astronomy and how to use the antenna as an educational resource. Also, teachers are provided with learning activities they can do with their students and focused on the classroom implementation of the project within an interdisciplinary framework. PARTNeR provides students with firsthand experience in radio astronomy science. Thus, remote radio astronomical observations allow students to learn with a first rate scientific equipment the basics of radio astronomy research, aiming to arouse scientific careers and positive attitudes toward science. In this contribution we show the current observational programs and some recent results.

  13. Satellite Cloud Computing

    Microsoft Academic Search

    Kamen Kanev; Nikolay N. Mirenkov

    2011-01-01

    In this work we present a novel concept for satellite based cloud computing integrating virtualized information resources from satellites and from the Internet. We first discuss the role of satellites in the infrastructure of cloud computing. Second we focus on some practical aspects of cloud computing, considering different configurations for access to satellite channels. We follow with reporting on our

  14. Weather satellite launched

    NASA Astrophysics Data System (ADS)

    Zielinski, Sarah

    2006-06-01

    NASA launched on 24 May the weather satellite GOES-N, the first of the new N series of Geostationary Operational Environmental Satellites. The satellite, which becomes GOES-13 once it reaches its final orbit, joins the U.S. National Oceanic and Atmospheric Administration collection of weather satellites that provide the agency with data for weather forecasts and warnings. The GOES-N series has several improvements over previous GOES satellites. A highly stable pointing platform will allow improved performance from the satellite's sounder-which gathers atmospheric data- and its imager. In addition, the satellite will enable NOAA to improve forecasts and warnings of solar disturbances.

  15. Error-free command link for sounding rockets and satellites

    NASA Astrophysics Data System (ADS)

    Ringstrand, Hans

    2003-08-01

    The Swedish Space Corporation has developed an error-free command uplink system for sounding rockets and satellites. The system architecture allows for safe command transmission without any time penalties during normal operation, and it recovers fast and wholly transparent from transmission errors without any user or operator interaction. The implementation is partly based on the CCSDS recommendations regarding satellite uplinks, but modified to better suit the PCM-based downlink systems, normally used for sounding rockets systems and small satellites. The system has proven extremely efficient and reliable during several small- and micro satellite projects such as ODIN, TeleFoton and Astrid-2. This paper presents the system architecture and shows the details for the implementations used in the Swedish scientific satellites ODIN and Astrid-2.

  16. Outer planet satellites

    SciTech Connect

    Schenk, P.M. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

    1991-01-01

    Recent findings on the outer-planet satellites are presented, with special consideration given to data on the rheologic properties of ice on icy satellites, the satellite surfaces and exogenic processes, cratering on dead cratered satellites, volcanism, and the interiors of outer-planet satellites. Particular attention is given to the state of Titan's surface and the properties of Triton, Pluto, and Charon. 210 refs.

  17. Radio Science Concepts and Approaches for Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

    Anderson, J. D.; Asmar, S. W.; Castillo, J. C.; Folkner, W. M.; Konopliv, A. S.; Marouf, E. A.; Rappaport, N. J.; Schubert, G.; Spilker, T. R.; Tyler, G. L.

    2003-01-01

    Radio Science experiments have been conducted on most deep space missions leading to numerous scientific discoveries. A set of concepts and approaches are proposed for the Jupiter Icy Moons Orbiter (JIMO) to apply Radio Science tools to investigate the interior structures of the Galilean Satellites and address key questions on their thermal and dynamical evolution. Measurements are identified that utilize the spacecraft's telecommunication system. Additional instruments can augment these measurements in order to leverage observational synergies. Experiments are also offered for the purpose of investigating the atmospheres and surfaces of the satellites.

  18. Integrated Satellite Control in REIMEI (INDEX) Satellite

    NASA Astrophysics Data System (ADS)

    Fukuda, Seisuke; Mizuno, Takahide; Sakai, Shin-Ichiro; Fukushima, Yousuke; Saito, Hirobumi

    REIMEI/INDEX (INnovative-technology Demonstration EXperiment) is a 70kg class small satellite which the Institute of Space and Astronautical Science, Japan Exploration Agency, ISAS/JAXA, has developed for observation of auroral small-scale dynamics as well as demonstration of advanced satellite technologies. An important engineering mission of REIMEI is integrated satellite control using commercial RISC CPUs with a triple voting system in order to ensure fault-tolerance against radiation hazards. Software modules concerning every satellite function, such as attitude control, data handling, and mission applications, work cooperatively so that highly sophisticated satellite control can be performed. In this paper, after a concept of the integrated satellite control is introduced, the Integrated Controller Unit (ICU) is described in detail. Also unique topics in developing the integrated control system are shown.

  19. A Deep Space Network Portable Radio Science Receiver

    NASA Technical Reports Server (NTRS)

    Jongeling, Andre P.; Sigman, Elliott H.; Chandra, Kumar; Trinh, Joseph T.; Navarro, Robert; Rogstad, Stephen P.; Goodhart, Charles E.; Proctor, Robert C.; Finley, Susan G.; White, Leslie A.

    2009-01-01

    The Radio Science Receiver (RSR) is an open-loop receiver installed in NASA s Deep Space Network (DSN), which digitally filters and records intermediate-frequency (IF) analog signals. The RSR is an important tool for the Cassini Project, which uses it to measure perturbations of the radio-frequency wave as it travels between the spacecraft and the ground stations, allowing highly detailed study of the composition of the rings, atmosphere, and surface of Saturn and its satellites.

  20. Corporate failure as a means to corporate responsibility

    Microsoft Academic Search

    Dwight R. Lee; Richard B. McKenzie

    1994-01-01

    Milton Friedman has argued that corporations have no responsibility to society beyond that of obeying the law and maximizing profits for shareholders. Individuals may have social responsibilities according to Friedman, but not corporations.

  1. Low-cost small satellites for astrophysical missions

    SciTech Connect

    Priedhorsky, W.C.

    1989-01-01

    A miniature satellite is a low-cost platform to support a small space experiment. Space astrophysics has been hindered by decades-long delays in important experiments. With miniature satellites, one hopes to reduce both experiment cost and lead time to an affordable level. Miniature satellites are not a new idea. The first scientific satellites, including Explorer I, were small and developed on a timescale of months. Important science was done by these pioneer missions. Though the easy discoveries have been made, important missions in exploration and follow-up can still be carried out from small platforms. Successful small satellite programs continue to this day. These include the OSCAR amateur radio satellite program, in which 12 small satellites, built by amateurs, have been flown over 25 years with no satellite failures (Fleeter, 1988). Two small free-flyers, GLOMAR and NUSAT, were ejected from the Shuttle in 1985. GLOMAR, a radio-relay experiment, was built in less than a year for under $1 million, and operated over a year in orbit. Small satellite projects continue to this day. Approaching launch are the Air Force STACKSAT array of 3 small satellites (P87-2), a number of other small satellites under Department of Defense auspices. The Air Force Space Test Program is developing a standard small experiment platform called STEP (Space Test Experiment Platform). NASA has started a small explorer program, beginning with SAMPEX, a solar and magnetospheric particle explorer, FAST, a fast auroral snapshot experiment, and SWAS, a submillimeter astronomy experiment. 5 refs., 2 figs., 2 tabs.

  2. The Frequency Spectrum Radio.

    ERIC Educational Resources Information Center

    Howkins, John, Ed.

    1979-01-01

    This journal issue focuses on the frequency spectrum used in radio communication and on the World Administrative Radio Conference, sponsored by the International Telecommunication Union, held in Geneva, Switzerland, in the fall of 1979. Articles describe the World Administrative Radio Conference as the most important radio communication conference…

  3. The Radio Amateur's Handbook.

    ERIC Educational Resources Information Center

    Blakeslee, Douglas, Ed.

    The objectives of this basic reference work for the radio amateur are to present radio theory and practice in terms of application and to reflect both the fundamentals and the rapidly-advancing technology of radio communications so that the radio amateur will have a guide to what is practical, meaningful, proven, and useful. Twenty-three chapters…

  4. Radio Controlled Clocks

    Microsoft Academic Search

    Michael A. Lombardi

    Radio controlled clocks have existed for decades, but have become far more common in the United States in recent years, due mainly to the explosion of new products that receive time signals from NIST radio station WWVB. This paper explores the history of radio controlled clocks, how they work, and the types of radio signals that control them.

  5. Sustainable Development and Corporate Environmental Responsibility: Evidence from Chinese Corporations

    Microsoft Academic Search

    Mao He; Juan Chen

    2009-01-01

    China is currently experiencing rapid economic growth. The price of this, however, is environment pollution. Many Chinese\\u000a corporations are lacking in corporate environmental responsibility (CER). Therefore, this study employs data from Chinese\\u000a and multinational corporations to identify why Chinese corporations seldom engage in CER by investigating their motivations\\u000a and stakeholders. The results show that the most important reason why Chinese

  6. Corporate Social Responsibility from the Perspective of Corporate Secretaries

    Microsoft Academic Search

    Samuel O. Idowu

    \\u000a Corporate secretaries make a considerable contribution to corporate social responsibility (CSR) processes by the nature of\\u000a the positions and responsibilities they hold in organisations. They act as a servant or full member of the board of directors,\\u000a the body that formulates corporate strategies; which are subsequently executed by executive directors. When corporate secretaries\\u000a become full members of the board, they

  7. Space satellites from the world's garage-the story of AMSAT

    Microsoft Academic Search

    K. Baker; D. Jansson

    1994-01-01

    AMSAT is a worldwide group of Amateur Radio Operators (Hams) who share an active interest in building, launching and then communicating with each other through non-commercial Amateur Radio satellites. By any measure, AMSAT's track record has been impressive. Since its founding 25 years ago, AMSAT has used predominantly volunteer labor and donated resources to design, construct, and, with the added

  8. Comparison of ionospheric scintillation models with experimental data for satellite navigation applications

    Microsoft Academic Search

    B. Forte; S. M. Radicella

    2003-01-01

    When traversing drifting ionospheric irregularities, a radio wave experiences fluctuations in its amplitude and phase: the fluctuations characteristics depend on the radio frequency, magnetic and solar activity, time of day, season of the year and magnetic latitude of the observation point in the case of satellite to ground links. Nowadays, one of the most important field where knowledge of ionospheric

  9. Tracking Data Relay Satellite System (TDRSS) VHF propagation study

    NASA Technical Reports Server (NTRS)

    Schleicher, L. A. H.; Llewellyn, S. K.; Bent, R. B.

    1973-01-01

    A study performed to investigate the use of the Bent Ionospheric Model in computing corrections to the range and range rate measurements of the TDRSS satellites is documented. Several orbital configurations between the two satellites are discussed as to their effects on total electron content along the radio path between the satellites. Problem areas in the accurate computation of total electron content and range rate corrections are also discussed. The Bent Ionospheric Model gives the electron density versus height profile as a function of latitude, longitude, height, time, season, and solar flux.

  10. 2009 IBM Corporation 2009 IBM Corporation IMS and Java

    E-print Network

    1 © 2009 IBM Corporation© 2009 IBM Corporation IMS and Java for Application Modernization Barbara November 4-5, 2009 This presentation discusses use of IMS and Java to modernize your applications. #12;2 2 IMS © 2009 IBM Corporation Agenda Java basics IMS Java basics IMS Java Applications IMS Database

  11. European corporate sustainability framework for managing complexity and corporate transformation

    Microsoft Academic Search

    Marcel van Marrewijk; Teun W. Hardjono

    2003-01-01

    The European Corporate Sustainability Framework (ECSF) is a new generation management framework, aimed to meet increased corporate complexity and support corporate transformation towards more sustainable ways of doing business. It is a multi-layer, integral business framework with an analytical, contextual, situational and dynamic dimension. Analytically, the framework is structured according to four focus points - the constitutional, conceptual, behavioural and

  12. 27 CFR 41.193 - Corporate documents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Products Importers § 41.193 Corporate documents. Every corporation...191, a true copy of the corporate charter or a certificate of corporate existence or incorporation...sign documents or otherwise act in behalf of the...

  13. 27 CFR 40.63 - Corporate documents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Tobacco Products § 40.63 Corporate documents. Every corporation...40.62, a true copy of the corporate charter or a certificate of corporate existence or incorporation...sign documents or otherwise act in behalf of the...

  14. 27 CFR 41.234 - Corporate documents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Processed Tobacco § 41.234 Corporate documents. Every corporation...41.231 a true copy of the corporate charter or a certificate of corporate existence or incorporation...sign documents or otherwise act in behalf of the...

  15. 27 CFR 40.494 - Corporate documents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Processed Tobacco § 40.494 Corporate documents. Every corporation...40.492 a true copy of the corporate charter or a certificate of corporate existence or incorporation...sign documents or otherwise act in behalf of the...

  16. CORPORATE SUSTAINABILITY, STRATEGY AND ACCOUNTING CONTROLS: AN

    E-print Network

    Paris-Sud XI, Université de

    1 CORPORATE SUSTAINABILITY, STRATEGY AND ACCOUNTING CONTROLS: AN EXPLORATION OF CORPORATE, with the increasing interest in sustainability comes the challenge of not only developing corporate sustainability-based management controls support the implementation of a sustainability strategy in multinational corporations

  17. The geostationary orbit and satellite communications: concepts older than commonly supposed

    Microsoft Academic Search

    N. Brady

    2002-01-01

    The first proposal for a radio-equipped, man-made satellite in geostationary orbit is customarily attributed to author Arthur Charles Clarke (1917-), however, he makes no claim to having originated the geostationary orbit. Clarke's now classic article, in the October 1945 issue of Wireless World described a system of worldwide broadcasting via three satellites in geostationary orbit. In the article, Clarke listed

  18. 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…

  19. Throughput and Delay Performance of Mobile Internet Applications Using LEO Satellite Access

    Microsoft Academic Search

    P. Loreti; M. Luglio; R. Kapoor; J. Stepanek; M. Gerla; F. Vatalaro; M. A. Vazquez-Castro

    Low Earth Orbit (LEO) satellites are an essential complement of the cellular radio infrastructure, especially the Universal Mobile Telecommunications System (UMTS), for mobile (pedestrian and, more important, vehicular) access to the Internet in sparsely populated areas, where high bandwidth UMTS cells cannot be economically deployed. LEO users would eventually switch between the satellite segment and the terrestrial one depending on

  20. The Impact of Pulsed RFI on the Coded BER Performance of the Nonlinear Satellite Communication Channel

    Microsoft Academic Search

    AARON WEINBERG

    1981-01-01

    The coded bit error rate (BER) performance of a satellite communications system, wherein the satellite repeater contains an arbitrary nonlinearity and the system operates in the presence of pulsed radio frequency interference (RFI), is examined. A major result is an analytic method for determining soft decision statistics of the receiver demodulator output in which pulsed RFI effects are accounted for.

  1. The Illiquidity of Corporate Bonds

    E-print Network

    Bao, Jack

    This paper examines the illiquidity of corporate bonds and its asset-pricing implications. Using transactions data from 2003 to 2009, we show that the illiquidity in corporate bonds is substantial, significantly greater ...

  2. Corporate governance and banking regulation

    E-print Network

    Alexander, Kern

    The globalisation of banking markets has raised important issues regarding corporate governance regulation for banking institutions. This research paper addresses some of the major issues of corporate governance as it relates to banking regulation...

  3. Corporate governance and insider trading

    E-print Network

    Rozanov, Konstantin A

    2008-01-01

    I investigate the relation between corporate governance and insider trading by corporate executives. Despite the general view that trade on non-public information adversely affects capital market participants, the impact ...

  4. BeiDou Navigation Satellite System and its time scales

    NASA Astrophysics Data System (ADS)

    Han, Chunhao; Yang, Yuanxi; Cai, Zhiwu

    2011-08-01

    The development and current status of BeiDou Navigation Satellite System are briefly introduced. The definition and realization of the system time scales are described in detail. The BeiDou system time (BDT) is an internal and continuous time scale without leap seconds. It is maintained by the time and frequency system of the master station. The frequency accuracy of BDT is superior to 2 × 10-14 and its stability is better than 6 × 10-15/30 days. The satellite synchronization is realized by a two-way time transfer between the uplink stations and the satellite. The measurement uncertainty of satellite clock offsets is less than 2 ns. The BeiDou System has three modes of time services: radio determination satellite service (RDSS) one-way, RDSS two-way and radio navigation satellite service (RNSS) one-way. The uncertainty of the one-way time service is designed to be less than 50 ns, and that of the two-way time service is less than 10 ns. Finally, some coordinate tactics of UTC from the viewpoint of global navigation satellite systems (GNSS) are discussed. It would be helpful to stop the leap second, from our viewpoint, but to keep the UTC name, the continuity and the coordinate function unchanged.

  5. Youth Radio

    NSDL National Science Digital Library

    With an impressive headquarters in downtown Oakland, Youth Radio is fast becoming a compelling and insightful media phenomenon that should be watched closely. Their mission is a laudable one, and as their website puts it, â??â?¦. is to promote young peopleâ??s intellectual creative and professional growth through training and access to media and to produce the highest quality original media for local and national outlets.â? Of course, the real heart of the site contains the actual programming, which is streamed 24 hours a day, 7 days a week. Along with unique mix of music, individuals can listen to a host of stories reported by young people. Visitors can also browse a list of recently added stories by topic, which include relationships, society, sports, poetry, and health. Those who are hoping to get some of the basic flavor of the offerings here would do well to take a look at the story featuring reporting from a group of Berkeley High School students at the World Social Forum in Caracas, or by listening to the commentary offered by Lauryn Silverman on the modern conundrum of multi-tasking.

  6. Radio frequency detection assembly and method for detecting radio frequencies

    DOEpatents

    Cown, Steven H. (Rigby, ID); Derr, Kurt Warren (Idaho Falls, ID)

    2010-03-16

    A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

  7. Corporate Strategies for Sustainable Innovations

    Microsoft Academic Search

    Marlen Arnold

    \\u000a Rerouting social and corporate activities concerning sustainable change is one of the key challenges for many businesses today\\u000a and in the near future. Implementing sustainable requirements in corporations necessitates the initiation of corporate strategic\\u000a change and the development of sustainable innovations. In the light of a wide variation of corporate activities to cope with\\u000a these challenges, the following questions arise:

  8. Comparative and International Corporate Governance

    Microsoft Academic Search

    Ruth V. Aguilera; Gregory Jackson

    2010-01-01

    In this article, we examine the state of the art in comparative and international corporate governance by identifying the key research questions, main concepts, and paradigms of explanations of cross?country diversity in corporate governance. First, we discuss the multiple definitions of corporate governance across disciplines and explore how this multi?dimensional nature of corporate governance posses challenges when making cross?national comparisons.

  9. Galileo satellite antenna modeling

    NASA Astrophysics Data System (ADS)

    Steigenberger, Peter; Dach, Rolf; Prange, Lars; Montenbruck, Oliver

    2015-04-01

    The space segment of the European satellite navigation system Galileo currently consists of six satellites. Four of them belong to the first generation of In-Orbit Validation (IOV) satellites whereas the other two are Full Operational Capability (FOC) satellites. High-precision geodetic applications require detailed knowledge about the actual phase center of the satellite and receiver antenna. The deviation of this actual phase center from a well-defined reference point is described by phase center offsets (PCOs) and phase center variations (PCVs). Unfortunately, no public information is available about the Galileo satellite antenna PCOs and PCVs, neither for the IOV, nor the FOC satellites. Therefore, conventional values for the IOV satellite antenna PCOs have been adopted for the Multi-GNSS experiment (MGEX) of the International GNSS Service (IGS). The effect of the PCVs is currently neglected and no PCOs for the FOC satellites are available yet. To overcome this deficiency in GNSS observation modeling, satellite antenna PCOs and PCVs are estimated for the Galileo IOV satellites based on global GNSS tracking data of the MGEX network and additional stations of the legacy IGS network. Two completely independent solutions are computed with the Bernese and Napeos software packages. The PCO and PCV values of the individual satellites are analyzed and the availability of two different solutions allows for an accuracy assessment. The FOC satellites are built by a different manufacturer and are also equipped with another type of antenna panel compared to the IOV satellites. Signal transmission of the first FOC satellite has started in December 2014 and activation of the second satellite is expected for early 2015. Based on the available observations PCO estimates and, optionally PCVs of the FOC satellites will be presented as well. Finally, the impact of the new antenna model on the precision and accuracy of the Galileo orbit determination is analyzed.

  10. Space telecommunications. III - The ground sector. Satellite telecommunications systems

    NASA Astrophysics Data System (ADS)

    Lombard, D.; Monnot, M.; Payet, G.; Rancy, F.; Ranvoisy, P.; Cazemajou, J.

    The operations, equipment, and principles of ground stations for communictions satellites are adescribed. The evolution of ground station configurations and capabilities is explored, with attention given to antenna design and operations, particularly in interfaces with Intelsat spacecraft. Tracking systems are detailed, together with the radio equipment and signal characteristics, the features of small earth stations, and earth stations for reception of Symphonie satellite television signals. Various communications satellite systems are described, including those of Canada, France, the U.S., the U.S.S.R., and Japan, and consideration is given to mobile services linked to satellites. Systems and appliactions for satellite backscattering are outlined and military use of communications spacecraft are analysed. Finally, the f eatures of the Eutalsat, Symphonie, and Telecom I systems and performance are presented. No individual items are abstracted in this volume

  11. Institutional Conditions of Corporate Citizenship

    Microsoft Academic Search

    Ronald Jeurissen

    2004-01-01

    Exploring the concept of citizenship from the history of political philosophy provides suggestions about what corporate citizenship could mean. The metaphor of corporate citizenship suggests an institutional approach to corporate social responsibility. Citizenship is a social role, characterized by an orientation towards the social contract, collective and active responsibility, as well as a positive attitude towards the juridical state. By

  12. Corporate-Like Financial Statements?

    ERIC Educational Resources Information Center

    Weis, Frederick M.

    1999-01-01

    A survey of 120 top independent national liberal arts colleges ranked in "U.S. News and World Report" compared the structure of their financial reports to those of publicly held corporations. Results indicate that the colleges' forms strongly resemble those of corporations, but are not as readable as the corporate forms. (MSE)

  13. CORPORATE SERVICES EXPENSE MANAGEMENT SOLUTIONS

    E-print Network

    ® Corporate Card 3 Spending power when you need it 4 Get the cash you need instantly Emergency Card may visit a participating financial institution or credit union. #12;5 Emergency Card ReplacementCORPORATE SERVICES EXPENSE MANAGEMENT SOLUTIONS Welcome to the American Express® Corporate Card

  14. Blocks, Liquidity, and Corporate Control

    Microsoft Academic Search

    Patrick Bolton; Ernst-Ludwig von Thadden

    1998-01-01

    The paper develops a simple model of corporate ownership structure in which costs and benefits of ownership concentration are analyzed. The model compares the liquidity benefits obtained through dispersed corporate ownership with the benefits from efficient management control achieved by some degree of ownership concentration. The paper reexamines the free-rider problem in corporate control in the presence of liquidity trading,

  15. The Missing Dynamic: Corporations, Individuals and Contracts

    Microsoft Academic Search

    Arun A. Iyer

    2006-01-01

    There are two opposing views on the nature of corporations in contemporary debates on corporate social responsibility. Opponents of corporate personhood hold that a corporation is nothing but a group of individuals coming together to achieve certain goals. On the other hand, the advocates of corporate personhood believe that corporations are persons in their own right existing over and above

  16. Satellite Home Tutorials vs. Satellite Classroom Tutorials.

    ERIC Educational Resources Information Center

    Beyth-Marom, Ruth; Yafe, Edna; Privman, Meira; Harpaz, Hamutal Razy

    In this study, students who registered for a course at the Open University of Israel could choose the tutorial method they preferred: group face-to-face tutorials with a local tutor in their residential vicinity; tutorials via satellite broadcasting to groups of students around the country; or getting the same satellite tutorial at home on the…

  17. Interference Mitigation Techniques for Broadband Satellite L. Cottatellucci*

    E-print Network

    Müller, Ralf R.

    MPA = Multi-Port Amplifier MUD = Multi-User Detector RF = Radio Frequency RL = Return Link * Now presents an overview of possible interference mitigation techniques aiming at increasing the system-pipe transparent satellite is assumed. After a general overview, the paper concentrates on the assessment of Linear

  18. Interference Mitigation Techniques for Broadband Satellite L. Cottatellucci * ,

    E-print Network

    Müller, Ralf R.

    MPA = Multi­Port Amplifier MUD = Multi­User Detector RF = Radio Frequency RL = Return Link * Now presents an overview of possible interference mitigation techniques aiming at increasing the system­pipe transparent satellite is assumed. After a general overview, the paper concentrates on the assessment of Linear

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

    Microsoft Academic Search

    Arnett S. Dennis

    1962-01-01

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

  20. NASA-GSFC ionospheric corrections to satellite tracking data

    NASA Technical Reports Server (NTRS)

    Schmid, P. E.; Bent, R. B.; Llewellyn, S. K.; Nesterczuk, G.; Rangaswamy, S.

    1971-01-01

    An overview is presented of the development, verification, and recent implementation of the NASA-GSFC ionospheric model for satellite tracking data corrections. This model was incorporated into the Goddard Trajectory Determination System which is providing continuous trajectory computation support for the lunar orbiting Radio Astronomy Explorer-B launched on 10 June 1973.

  1. Potential Spacecraft-to-Spacecraft Radio Observations with EJSM: Wave of the Future? (Invited)

    Microsoft Academic Search

    E. A. Marouf; P. Tortora; S. W. Asmar; W. M. Folkner; D. Hinson; L. Iess; I. R. Linscott; R. D. Lorenz; I. C. Mueller-Wodarg

    2010-01-01

    Future active radio observations of planetary and satellite atmospheres and surfaces could significantly benefit form the presence of two or more spacecraft in orbit around a target object. Traditionally, radio occultation and bistatic surface scattering experiments have been conducted using a single spacecraft operating in the Downlink (DL) configuration, with the spacecraft transmitting and at least one Earth-based station receiving.

  2. The Effect of Radio-Collar Weight on Survival of Migratory Caribou

    E-print Network

    Festa-Bianchet, Marco

    . We compared the survival of 269 randomly selected adult migratory caribou (Rangifer tarandus) fitted, radio transmitter weight, Rangifer tarandus, satellite/VHF collars, survival, Ungava caribou. Radio such as greater snow goose (Anser caerulescens atlanticus) or caribou (Rangifer tarandus) that travel hundreds

  3. Lessons from Enlightened Corporations.

    ERIC Educational Resources Information Center

    Blankstein, Alan M.

    1992-01-01

    The formula for improving U.S. schools can be found in the philosophy that helped transform Japanese industry and in Deming's 14 principles, emulated by many corporations. Deming's arguments against appraising individual performance through quotas or numerical goals call into question schools' current grading and merit pay practices. (12…

  4. PROecom Solutions: Corporate Identity

    Microsoft Academic Search

    Jane Doe

    Managing the use and implementation of the graphic elements which make up your corporate identity can present a substantial challenge. Across all industries, companies are faced with the task of continuously managing their visual identity assets to ensure that they are represented appropriately and consistently at all times. Imagine a system that would streamline this process and ensure the consistent

  5. Trends in Corporate Governance

    Microsoft Academic Search

    BENJAMIN E. HERMALIN

    2005-01-01

    The popular press and scholarly studies have noted a number of trends in corporate governance. This article addresses, from a theoretical perspective, whether these trends are linked. And, if so, how? The article finds that a trend toward greater board diligence will lead, sometimes through subtle or indirect mechanisms, to trends toward more external candidates becoming CEO, shorter tenures for

  6. Corporate Training in Museums

    ERIC Educational Resources Information Center

    Causey, Adera

    2011-01-01

    Museums often court corporate audiences through special event rentals and development and promotional partnerships. But we rarely approach them as potential adult learners. In overlooking them, we miss the potential of reaching a large number of often novice museum participants who can gain from gallery learning and develop a relationship with our…

  7. Corporate Management Invades Academe.

    ERIC Educational Resources Information Center

    Nielsen, Robert M.

    Measures taken to cut costs at the expense of the faculty and the loss in academic quality are shown to be part of a well-organized plan being adopted throughout higher education. Problems have arisen from the activities of the private or semi-private corporate consulting organization in higher education. Taken as a whole, the uncritical use of…

  8. Corporate Culture and Geopolitics

    Microsoft Academic Search

    Jean Marc de Leersnyder

    2002-01-01

    Geopolitics represents a privileged field for leading public players (the States themselves, government bodies, international organisations) and other bodies from the non-profit sector (NGOs). In the modern world, business has become one of the biggest contributors to geopolitics. Corporate strategy is developed within what is now a reconfigured space. This reconfiguration is the result of three factors: the geopolitical situation,

  9. Satellite RNAs and Satellite Viruses of Plants

    PubMed Central

    Hu, Chung-Chi; Hsu, Yau-Heiu; Lin, Na-Sheng

    2009-01-01

    The view that satellite RNAs (satRNAs) and satellite viruses are purely molecular parasites of their cognate helper viruses has changed. The molecular mechanisms underlying the synergistic and/or antagonistic interactions among satRNAs/satellite viruses, helper viruses, and host plants are beginning to be comprehended. This review aims to summarize the recent achievements in basic and practical research, with special emphasis on the involvement of RNA silencing mechanisms in the pathogenicity, population dynamics, and, possibly, the origin(s) of these subviral agents. With further research following current trends, the comprehensive understanding of satRNAs and satellite viruses could lead to new insights into the trilateral interactions among host plants, viruses, and satellites. PMID:21994595

  10. Satellite broadcasting in Europe

    NASA Astrophysics Data System (ADS)

    Bartholome, P.

    1984-05-01

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

  11. Field Operation of a Surgical Robot via Airborne Wireless Radio Link

    E-print Network

    satellites can provide wireless communication for use in mobile telesurgery, long latency as the resultField Operation of a Surgical Robot via Airborne Wireless Radio Link M.H. Lum, D.C.W. Friedman, H of signal transmission distance precludes robust use of satellite communications in telesurgery

  12. An IF Digital Down-Converter for Software Radio DVB-S2 Receivers

    Microsoft Academic Search

    Panayiotis Savvopoulos; Theodore Antonakopoulos

    2007-01-01

    The second generation of DVB specs, DVB-S2, was developed for satisfying the today's needs for reliable and effective broadband satellite communication services even under `hostile' conditions. This is achieved by exploiting the new advances in the fields of coding and modulation. Software defined radio (SDR) proves to be an enabling technology for future multimode and reconfigurable satellite receivers. This work

  13. 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.

  14. Computing Location from Ambient FM Radio Signals Adel Youssef John Krumm, Ed Miller, Gerry Cermak, Eric Horvitz

    E-print Network

    Krumm, John

    1 Computing Location from Ambient FM Radio Signals Adel Youssef John Krumm, Ed Miller, Gerry Cermak, MD 20742 Microsoft Research Microsoft Corporation One Microsoft Way Redmond, WA USA 98052 adel computing, Bayesian inference. #12;2 Computing Location from Ambient FM Radio Signals Adel Youssef John

  15. In memoriam: Grote Reber 1911-2002 founder of radio astronomy

    NASA Astrophysics Data System (ADS)

    Peratt, A. L.

    2003-12-01

    Grote Reber, amateur radio operator W9GFZ, died December 20, 2002 in Tasmania. He would have been 91 years old on December 22nd. Reber is acknowledged as the Father of Radio Astronomy and the inventor of the first true radio telescope. With the advent of space satellites, his greatest legacy may well be his invention of the parabolic dish, designed to receive nonterrestrial electromagnetic radiation, a concept that has revolutionized worldwide communication.

  16. Hearing America: A Century of Music on the Radio

    NSDL National Science Digital Library

    As one of the lyrics by the Brothers Gershwin goes: "They told Marconi/wireless was a phony." Of course, the wireless world of the radio and its galaxy of musical choices has changed from the transmission of mere Morse code in its early decades to today's overwhelming choices afforded by different satellite radio companies. This recent documentary by the American RadioWorks program explores the history of American radio, and how it has been the site of many a cultural battle over the past ten decades. This site allows users to listen to the entire program, and it also includes a number of nice web features. These include maps that chart the growth of AM and FM stations from 1922 through 2006 and some engaging essays, such as "Radio Fights Jim Crow" and "Sex, Race and Rock & Roll".

  17. IMAGE Satellite Scale Model

    NSDL National Science Digital Library

    2012-08-03

    This is an activity about scale model building. Learners will use mathematics to determine the scale model size, construct a pattern, and build a paper scale model of the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite, the first satellite mission to image the Earth's magnetosphere. This is the second activity in the Solar Storms and You: Exploring Satellite Design educator guide.

  18. Early satellite program developments

    NASA Technical Reports Server (NTRS)

    Kellogg, W. W.

    1982-01-01

    A historical overview of the pioneer projects for the development of meteorological satellites is given. In addition, the parallel development of the responsible space agencies and panels is addressed. The Vanguard 2 satellite, the first Earth radiation experiment, and the vidicon equipped TIROS-1 satellite are discussed.

  19. Tracking Weather Satellites.

    ERIC Educational Resources Information Center

    Martin, Helen E.

    1996-01-01

    Describes the use of weather satellites in providing an exciting, cohesive framework for students learning Earth and space science and in providing a hands-on approach to technology in the classroom. Discusses the history of weather satellites and classroom satellite tracking. (JRH)

  20. Small Astronomy Satellite (SAS)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Series of three pioneering NASA scientific satellites, launched 1970-75. SAS-1, also known as UHURU (Freedom), was the first dedicated x-ray astronomy satellite. SAS-2 was the first satellite to detect gamma rays, and it discovered the enigmatic Geminga source. SAS-3 also carried x-ray experiments....

  1. Neptune's small inner satellites

    Microsoft Academic Search

    Peter Thomas; Joseph Veverka

    1991-01-01

    The six small inner satellites of Neptune discovered by Voyager 2 are described. Proteus (1989N1), the largest of these sattelites, has a mean radius of 208 +\\/-8 km, while the radius of the smallest, Naiad (1989N6), is 29 +\\/-6 km. The inner satellite system of Neptune is similar to that of Uranus in that the albedos of the satellites are

  2. NORAD satellite tracking

    Microsoft Academic Search

    Joseph J. F. Liu

    1987-01-01

    NORAD routinely tracks about 6000 orbiting objects. During the last 30 days of orbital time, prior to reentry, special perturbations are used in the orbital update procedure. Besides routine orbit determination, NORAD does special tasks such as predicting satellite orbit conjunctions within 20 km, ephimerides of weather satellites, satellite decay predictions and other studies. Since their mission is operational, they

  3. Survey: National Environmental Satellite Service

    NASA Technical Reports Server (NTRS)

    1977-01-01

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

  4. Seamless Handovers in Cobra Teardrop Satellite Arrays

    NASA Astrophysics Data System (ADS)

    Draim, John E.; Cefola, Paul J.; Ernandes, Kenneth J.

    2007-06-01

    Satellite systems provide the most efficient and possibly the only means of achieving two-way global communications with mobile systems (ships, aircraft, and vehicular traffic). To date, such systems have used only circular orbits, either GEO or LEO. Medium altitude elliptical constellations, on the other hand, can provide an efficient and affordable alternative to these architectures. Users also benefit from their very high average and minimum elevation angles, resulting in minimum signal attenuation. Cobra Teardrop is unique in that it employs time synchronized 8-h left- and right-leaning elliptical orbits giving mid-latitude observers the illusion of viewing a single satellite continuously orbiting almost directly overhead! In reality, observers see six different satellites per day, for 4 h each (while in their active duty cycles). By design, Teardrop satellites are physically in very close proximity at the handover points. This favorable geometry can be utilized to achieve a seamless handover from one satellite to the other (not requiring any electronic buffering). Handover is accomplished at the precise instant that the total path lengths from the transmitting station through both satellites to the receiving station are exactly equal. In these improved Cobra Teardrop arrays, an order of magnitude increase in global communications capacity (equivalent GEO slots) can be realized over earlier Basic Cobra systems. For decades into the future, these new orbital systems could satisfy a widely expanding range of commercial, government, and military high data rate communication requirements. These would include, but not be limited to, satellite cellular, air traffic control, meteorological, and combat net radio systems. With these arrays, a much larger number of system operators could be supported, without mutual electronic interference, than would ever be possible with circular orbits.

  5. Weather Satellite and Orbits

    NSDL National Science Digital Library

    In this interactive, online module, students learn about satellite orbits (geostationary and polar), remote-sensing satellite instruments (radiometers and sounders), satellite images, and the math and physics behind satellite technology. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.

  6. Satellite Feature Identification: Cyclogenesis

    NSDL National Science Digital Library

    COMET

    2012-08-17

    This module, Satellite Feature Identification: Cyclogenesis, uses water vapor satellite imagery to present a satellite perspective of basic features associated with the formation and development of extratropical cyclones. First, through an initial case study, the precursor elements leading to cyclogenesis are identified. Then three conceptual views of different ways cyclogenesis can evolve are presented along with additional examples to illustrate the concepts. Finally a series of exercises, again using real case studies, are used to emphasize the important points and provide realistic scenarios describing some of the many ways cyclogenesis reveals itself on satellite imagery. This module is part of the series: 'Dynamic Feature Identification: The Satellite Palette'.

  7. Game Theoretical Analysis of Cognitive Radio Networks: An NCEL Perspective

    E-print Network

    Huang, Jianwei

    commercial service, from satellite broadcasting to wireless local-area network, has to compete for licensesGame Theoretical Analysis of Cognitive Radio Networks: An NCEL Perspective (Invited Review Paper) Jianwei Huang Network Communications and Economics Lab (NCEL) Department of Information Engineering

  8. Radio-wave propagation for space communications systems

    Microsoft Academic Search

    L. J. Ippolito

    1981-01-01

    The most recent information on the effects of Earth's atmosphere on space communications systems is reviewed. The design and reliable operation of satellite systems that provide the many applications in space which rely on the transmission of radio waves for communications and scientific purposes are dependent on the propagation characteristics of the transmission path. The presence of atmospheric gases, clouds,

  9. Swedish small satellites

    NASA Astrophysics Data System (ADS)

    Lundahl, Kaj; Von Schéele, Fredrik

    In 1986 the first Swedish small satellite VIKING was launched on the Ariane I rocket together with the French remote sensing satellite SPOT. This paper describes the development of the Swedish Small Satellite Program. The satellites have delivered excellent scientific data at a low cost by using streamlined project organisations, competitive procurement programs and piggy-back launch opportunities. The first micro satellite Astrid-1 was launched in January 1995 and will be followed by the launch of Astrid-2 in December 1998. The capable Odin small satellite will be launched in September 1999. SSC has completed a design study for ESA's SMART-1 probe destined to the Moon — and possibly beyond. SMART-1, planned for launch in 2001, will be used for both research and as a technology demonstrator for future projects. Future projects include micro and small satellites for ESA as Earth Explorer Opportunity Missions and for the Swedish National Space Board as galactic sky surveyors and atmospheric ozone deplition observers.

  10. Case study on complex sporadic E layers observed by GPS radio occultations

    NASA Astrophysics Data System (ADS)

    Yue, X.; Schreiner, W. S.; Zeng, Z.; Kuo, Y.-H.; Xue, X.

    2015-01-01

    The occurrence of sporadic E (Es) layers has been a hot scientific topic for a long time. The GNSS (global navigation satellite system)-based radio occultation (RO) has proven to be a powerful technique for detecting the global Es layers. In this paper, we focus on some cases of complex Es layers based on the RO data from multiple missions processed in UCAR/CDAAC (University Corporation for Atmospheric Research (UCAR) the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Data Analysis and Archive Center (CDAAC)). We first show some examples of multiple Es layers occurred in one RO event. Based on the evaluations between colocated simultaneous RO events and between RO and lidar observations, it could be concluded that some of these do manifest the multiple Es layer structures. We then show a case of the occurrence of Es in a broad region during a certain time interval. The result is then validated by independent ionosondes observations. It is possible to explain these complex Es structures using the popular wind shear theory. We could map the global Es occurrence routinely in the near future, given that more RO data will be available. Further statistical studies will enhance our understanding of the Es mechanism. The understanding of Es should benefit both Es-based long-distance communication and accurate neutral RO retrievals.

  11. Enhancing the Security of Corporate Wi-Fi Networks Using DAIR

    Microsoft Academic Search

    Paramvir Bahl; Ranveer Chandra; Jitendra Padhye; Alec Wolman

    2006-01-01

    We present a framework for monitoring enterprise wireless networks using desktop infrastructure. The framework is called DAIR, which is short for Dense Array of Inexpensive Radios. We demonstrate that the DAIR framework is useful for detecting rogue wireless devices (e.g., access points) attached to corporate networks, as well as for detecting Denial of Service attacks on Wi-Fi networks. Prior proposals

  12. Research BulletinMulti-disciplinary Insights in Competition and Regulation News Corporation

    E-print Network

    Feigon, Brooke

    for the news from TV, radio, newspapers and the internet, the BBC is the dominant player with a wholesale1 Research BulletinMulti-disciplinary Insights in Competition and Regulation News Corporation coverage of cartels and the OFT/Competition Commission merger Issue 21.indd 1 04/05/2011 09:22 #12;2 News

  13. Characterizing Mobility and Network Usage in a Corporate Wireless LocalArea Network

    E-print Network

    Characterizing Mobility and Network Usage in a Corporate Wireless Local­Area Network Magdalena Center pcastro@us.ibm.com Abstract Wireless local­area networks are becoming increas­ ingly popular [16] also studied the Metri­ com metropolitan­area packet radio wireless network, a public network

  14. The 18th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC'07) 1-4244-1144-0/07/$25.00 2007 IEEE.

    E-print Network

    Vouyioukas, Demosthenes

    or simply SITs. The DVB-RCS Hub is vital for the operation of the DVB-RCS satellite communications network the new developments in satellite networks such as DVB-RCS. In fact, satellite communication systemsThe 18th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications

  15. Radio Diaries on National Public Radio (NPR)

    NSDL National Science Digital Library

    Radio Diaries is a nonprofit radio production company which looks "to find extraordinary stories in ordinary places, to create original and moving first-person documentaries - true radio verite - from voices that are rarely heard." And that it does. Radio Diaries staff train all kinds of people -- from teenagers to the elderly -- to become reporters. These fledgling reporters create tapes about their area of interest, tell their stories, and send their product back to Radio Diaries. A collaborative editing process then ensues, and the end product is aired as part of National Public Radio's All Things Considered. The Radio Diaries site brings together an amazing range of recorded stories divided into adult and teen areas. Two examples of diaries on the site include a piece by a teenager from New York City with Tourette's Syndrome as well as the story of the last two known remaining Civil War widows whose husbands fought on opposing sides of the war. Users can listen to the recordings using RealPlayer, or they can read transcripts; other materials are occasionally included too. The site encourages users to send in their own story ideas and will provide even more support for creative ventures with their Handbook for Teen Reporters (available in January of 2000). The site also has a store section where tapes of various radio diaries are for sale.

  16. Fundamentals of Radio Telescopes

    Microsoft Academic Search

    Jingquan Cheng

    \\u000a In this chapter, a brief review of radio astronomical telescopes is provided. The fundamental concepts of radio antennas,\\u000a including radiation pattern, antenna gain, antenna temperature, antenna efficiency, and polarization, are introduced. These\\u000a concepts are important for readers outside the radio antenna field. The emphasis of this chapter is placed on the parameter\\u000a design of reflector radio telescope antennas. These parameter

  17. Triggered Jovian radio emissions

    NASA Technical Reports Server (NTRS)

    Calvert, W.

    1985-01-01

    Certain Jovian radio emissions seem to be triggered from outside, by much weaker radio waves from the sun. Recently found in the Voyager observations near Jupiter, such triggering occurs at hectometric wavelengths during the arrival of solar radio bursts, with the triggered emissions lasting sometimes more than an hour as they slowly drifted toward higher frequencies. Like the previous discovery of similar triggered emissions at the earth, this suggests that Jupiter's emissions might also originate from natural radio lasers.

  18. Radio frequency spectrum management

    Microsoft Academic Search

    E. J. Sujdak Jr.

    1980-01-01

    This thesis is a study of radio frequency spectrum management as practiced by agencies and departments of the Federal Government. After a brief introduction to the international agency involved in radio frequency spectrum management, the author concentrates on Federal agencies engaged in frequency management. These agencies include the National Telecommunications and Information Administration (NTIA), the Interdepartment Radio Advisory Committee (IRAC),

  19. Extragalactic Radio Sources

    ERIC Educational Resources Information Center

    Kellerman, Kenneth I.

    1973-01-01

    Discusses new problems arising from the growing observational data through radio telescope arrays, involving the origin of radio sources, apparent superluminal velocities, conversion of radio sources to relativistic particles, and the nature of compact opaque and extended transparent sources. New physics may be needed to answer these cosmological…

  20. Universal portable radio communications

    Microsoft Academic Search

    D. C. Cox

    1985-01-01

    In our highly mobile society, the provision of voice and data communications to people away from their wireline telephones has become a major communications frontier. Some emerging radio systems, e.g., cellular mobile radio, cordless telephone, and radio paging, have begun to penetrate this frontier. However, each of these approaches only partially satisfies portable communication needs. That is, the approaches do

  1. Introduction Big Radio Data

    E-print Network

    Prodiæ, Aleksandar

    Introduction VLBI Pulsars Summary Big Radio Data Ue-Li Pen CITA, UofT, CIFAR July 3, 2014U. Pen Big Radio Data #12;Introduction VLBI Pulsars Summary Overview History VLBI Processing Future U. Pen Big signal processing U. Pen Big Radio Data #12;Introduction VLBI Pulsars Summary VLBI Current experiments

  2. Radio Continuum Surveys

    NASA Astrophysics Data System (ADS)

    Jonas, Justin L.; Baart, Eddie E.

    1995-08-01

    The Rhodes University radio astronomy group has been involved in radio continuum mapping of southern extended radio sources since 1976. We describe the various mapping projects undertaken with the HartRAO telescope, particularly the Rhodes/HartRAO 2300 MHz all-sky survey, and speculate on future projects.

  3. The software radio architecture

    Microsoft Academic Search

    J. Mitola

    1995-01-01

    As communications technology continues its rapid transition from analog to digital, more functions of contemporary radio systems are implemented in software, leading toward the software radio. This article provides a tutorial review of software radio architectures and technology, highlighting benefits, pitfalls, and lessons learned. This includes a closer look at the canonical functional partitioning of channel coding into antenna, RF,

  4. Radio AGN Surveys

    E-print Network

    Carlos De Breuck; Wil van Breugel; Huub Rottgering; Chris Carilli

    2001-11-13

    We present a short overview of radio surveys for AGN, including the `complete' flux limited surveys and `filtered' surveys. We also describe our ultra-steep spectrum search for the highest redshift radio galaxies, and our follow-up VLA and ATCA observations of the most distant (z=5.19) and the most luminous z<2 radio galaxy known.

  5. Terrestrial structured radio emissions occurring close to the equatorial regions

    NASA Astrophysics Data System (ADS)

    Boudjada, Mohammed Y.; Galopeau, Patrick H. M.; Sawas, Sami; Berthelier, Jean-Jacques

    2015-04-01

    We study the occurrence of terrestrial radio emissions observed by the electric field experiment (ICE) onboard DEMETER micro-satellite. We principally consider the ICE observations recorded in the HF frequency range between 10 kHz and 3.175 MHz. A dynamic spectrum is recorded each half-orbit with a time and frequency resolutions, respectively, in the order of 3.25 kHz and 2.048 sec. The terrestrial structured radio emission is found to occur when the satellite is approaching the equatorial region of the Earth. It appears as a structured narrow band 'continuum' with a positive or negative low frequency drift rate, less than 1 kHz/s. The bandwidth is, on average, of about 30 kHz. We derive from our investigation the beam and the probable location of the emission source. We discuss the origin of this terrestrial radio emission and its dependence, or not, on the solar and geomagnetic activities.

  6. Modems for emerging digital cellular-mobile radio system

    NASA Astrophysics Data System (ADS)

    Feher, Kamilo

    1991-05-01

    Digital modem techniques for emerging digital cellular telecommunications-mobile radio system applications are described and analyzed. In particular, theoretical performance, experimental results, principles of operation, and various architectures of pi/4-QPSK (pi/4-shifted coherent or differential QPSK) modems for second-generation US digital cellular radio system applications are presented. The spectral/power efficiency and performance of the pi/4-QPSK modems (American and Japanese digital cellular emerging standards) are studied and briefly compared to GMSK (Gaussian minimum-shift keying) modems (proposed for European DECT and GSM cellular standards). Improved filtering strategies and digital pilot-aided (digital channel sounding) techniques are also considered for pi/4-QPSK and other digital modems. These techniques could significantly improve the performance of digital cellular and other digital land mobile and satellite mobile radio systems. More spectrally efficient modem trends for future cellular/mobile (land mobile) and satellite communication systems applications are also highlighted.

  7. Impact of the 1985 Space World Administrative Radio Conference on frequency/orbit planning and use

    NASA Technical Reports Server (NTRS)

    Miller, E. F.

    1986-01-01

    The 1985 World Administrative Radio Conference (WARC-ORB-85) was held to determine which space radio services should be planned and which planning methods should be used. The second session of this Conference (WARC-ORB-88) will meet to develop the required plans. This paper presents the results of WARC-ORB-85, assesses the impact of those decisions, and identifies the intersessional work to be conducted by administrations and the CCIR (Consultative Committee on International Radio). The major decisions of WARC-ORB-85 were: (1) the restriction of additional planning to the fixed satellite service at identified frequencies; and (2) the selection of a planning method consisting of two parts (a) an allotment plan, and (b) improved procedures. The paper also discusses WARC-ORB-85 decisions relative to the Region 2 broadcast satellite service plans at 12 GHz, feederlink planning for Regions 1 and 3 broadcast satellites at 12 GHz, and sound broadcast satellite service.

  8. Massachusetts Corporation for Educational Telecommunications: Models of Collaboration for the Integration of Telecommunications in Education.

    ERIC Educational Resources Information Center

    Flores, John G.

    1997-01-01

    The Massachusetts Corporation for Educational Telecommunications (MCET), a quasi-public agency, plays a leadership role in distance education and the integration of telecommunications and education locally and nationally. Operator of the Mass LearnPike satellite network and the Mass Ed OnLine LearnNet computer network, MCET provides expanded…

  9. Satellite systems for the direct radiation of broadcasting programs

    NASA Astrophysics Data System (ADS)

    Lothaller, W.

    1980-11-01

    A brief historical enumeration of the earliest satellite experiments is presented, concentrating first on NASA's ATS-6, the Canadian Technology Satellite, 'Hermes', and the Japanese Broadcasting Satellite for Experimental Purposes. The three European news satellites now in geostationary orbit are mentioned: Symphonie, a German-French joint project, the Italian research satellite, SIRIO-1, and the ESA Orbital Test Satellite. Specifications for ESA's two direct broadcasting satellite projects are discussed: the H-Sat, with its two transmitting channels per broadcasting program, the increased lobe span of the antennas, its traveling wave tube transmitters at 150 W and 450 W, and its frequencies of 12168.62 MHz and 12053.54 MHz; the L-Sat, based on the H-Sat, with an improved ECS system and a potential for more flexible and widespread service. Great attention is given to West Germany's TV-Sat, built in three modules - payload, service, driving - and is marked by its high capacity traveling wave tubes, an ultra-light solar generator, high precision infrared sensors, and a radio frequency ion thrust assembly that is low on fuel consumption. Finally mention is given to NORDSAT, the Scandinavian satellite, which on a 12 GHz frequency band will have a total of 13 channels.

  10. Expected results of Cassini Radio Science experiments

    NASA Astrophysics Data System (ADS)

    Castillo, J.; Rappaport, N.

    Cassini gravity radio science experiments scheduled from February 2005 to July 2008 are expected to improve our knowledge of the Saturnian system through direct measurements of gravity parameters performed in a multidisciplinary and comparative planetary science approach. In 2005, direct mass determination will be achieved for Enceladus, Hyperion, and Dione, as well as gravity field measurement of Rhea. Detection of an ocean suspected to lie within Titan is expected to happen by 2007. However, after the two first flybys scheduled in 2006, the determination of the dimensionless moment of inertia of this body will provide scientists with enough information to build detailed models to be compared with the Galilean satellites. Density determination of all major satellites will be performed through navigation passes scheduled throughout the tour. Accurate and independent determination of Saturn's high zonal harmonics up to degree 8 will provide crucial constraints on the interior of this giant planet by the end of the initial mission. Comparison of direct mass determination with values inferred from analytical theories is very important. Besides, density distribution sampling in the Saturnian system will provide new constraints on the models of evolution of Saturn's subnebula, as well as references for compared planetology with the Jovian satellites. This is particularly timely as a mission toward Jupiter is being scheduled in the frame of NASA New Frontiers program. Fresh geophysical observations of icy satellites and the finding or absence of a deep ocean within Titan will be crucial inputs for constraining numerical models of internal and external dynamics of this category of bodies. We will especially stress out the synergy between the information provided by the Radio Science Subsystems with the other instruments onboard Cassini to leverage our understanding of the phenomena responsible for the dynamics and evolution of the icy satellites.

  11. Approved Module Information for EE402B, 2014/5 Module Title/Name: Radio Systems and Personal

    E-print Network

    Neirotti, Juan Pablo

    Communications Systems: Introduce practical radio communications systems such as satellite and mobile Communications Systems Module Code: EE402B School: Engineering and Applied Science Module Type: Standard Module. MSc Wireless Communications & Networking. MSc Photonic Networks Engineering (MAPNET). Available

  12. Corporate Headquarters Cisco Systems, Inc.

    E-print Network

    Brody, James P.

    in accordance with Cisco's installation instructions, it may cause interference with radio and television with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment may be required to correct any interference to radio or television communications at your own expense

  13. Corporate Headquarters Cisco Systems, Inc.

    E-print Network

    Westall, James M.

    in accordance with Cisco's installation instructions, it may cause interference with radio and television radiate radio-frequency energy and, if not installed and used in accordance with the instruction manual may be required to correct any interference to radio or television communications at your own expense

  14. First LEO Satellite Constellation Based on GPS

    NASA Astrophysics Data System (ADS)

    Svehla, D.; Rothacher, M.

    2005-12-01

    In the beginning, an overview is given covering precise orbit determination (POD) of Low Earth Orbiting (LEO) satellites using GPS. Kinematic and reduced-dynamic POD approaches and results are presented for a single LEO satellite like CHAMP and for the first LEO formation flying in the case of the two GRACE satellites. It is shown that, when forming a GPS baseline in space between the two GRACE satellites, almost all ambiguities can be resolved to their integer values, leading to highly accurate orbit differences between the GRACE satellites on the two-millimeter level. The Taiwan-US mission FORMOSAT3/COSMIC will be the first mission at LEO altitudes with 6 satellites flying in a constellation making use of onboard GPS receivers. By forming GPS baselines between these 6 LEO satellites and by fixing ambiguities, a unique GPS network in space can be formed. Based on such a LEO network, orbits of the GPS satellites can be estimated simultaneously with the orbits of the LEO satellites without using measurements from the ground GPS network. However, as our simulation study shows, the orbit of one reference LEO satellite has to be kept fixed and assumed to be estimated, e.g., using SLR measurement. By adding GPS data from the ground IGS network, the strength of the whole system is considerably increased and the impact of a LEO constellation on the determination of global IGS parameters like Earth rotation, station coordinates, troposphere zenith delays and the orbits of the GPS satellites can be demonstrated. The simulation shows that FORMOSAT3/COSMIC satellites may have great impact on the IGS processing. Because SLR measurements are standard to externally validate satellite orbits and can easily indicate systematic errors or problems with attitude or GPS antenna characteristics, such satellites should be equipped with SLR reflectors. In addition, results obtained applying higher-order ionosphere corrections may be tested using LEO POD and may externally be validated by means of SLR measurements. The quality of radio occultation results depends critically on the quality of the orbits and fast near-real time POD. A reduced-dynamic POD approach based on Fourier series is presented. In contrast to the present POD approach based on the estimation of small velocity changes, it provides orbits with continuous first and second time derivatives (velocity and acceleration). This POD approach can be applied for both, near real-time and post-processed orbit determination and has the additional advantage that, when introducing a high-quality gravity field model (e.g. from GRACE), the non-conservative accelerations (air-drag, solar radiation) can be used to determine, e.g., air-densities or residual temporal gravity field variations. The FORMOSAT3/COSMIC mission poses a special challenge for POD due to the two sideways-pointing POD antennas. The GPS measurements from both GPS antennas have to be combined and processed together, as they are affected by different system delays. This problem may be critical when forming baselines between the LEO satellites and may degrade the accuracy of orbit determination. In this case the data pre-processing is also more difficult than for a zenith pointing GPS antenna. Using simulated GPS data, this problem is addressed and the impact on POD performance is presented.

  15. Digital audio and video broadcasting by satellite

    NASA Astrophysics Data System (ADS)

    Yoshino, Takehiko

    In parallel with the progress of the practical use of satellite broadcasting and Hi-Vision or high-definition television technologies, research activities are also in progress to replace the conventional analog broadcasting services with a digital version. What we call 'digitalization' is not a mere technical matter but an important subject which will help promote multichannel or multimedia applications and, accordingly, can change the old concept of mass media, such as television or radio. NHK Science and Technical Research Laboratories has promoted studies of digital bandwidth compression, transmission, and application techniques. The following topics are covered: the trend of digital broadcasting; features of Integrated Services Digital Broadcasting (ISDB); compression encoding and transmission; transmission bit rate in 12 GHz band; number of digital TV transmission channels; multichannel pulse code modulation (PCM) audio broadcasting system via communication satellite; digital Hi-Vision broadcasting; and development of digital audio broadcasting (DAB) for mobile reception in Japan.

  16. A direct broadcast satellite-audio experiment

    NASA Technical Reports Server (NTRS)

    Vaisnys, Arvydas; Abbe, Brian; Motamedi, Masoud

    1992-01-01

    System studies have been carried out over the past three years at the Jet Propulsion Laboratory (JPL) on digital audio broadcasting (DAB) via satellite. The thrust of the work to date has been on designing power and bandwidth efficient systems capable of providing reliable service to fixed, mobile, and portable radios. It is very difficult to predict performance in an environment which produces random periods of signal blockage, such as encountered in mobile reception where a vehicle can quickly move from one type of terrain to another. For this reason, some signal blockage mitigation techniques were built into an experimental DAB system and a satellite experiment was conducted to obtain both qualitative and quantitative measures of performance in a range of reception environments. This paper presents results from the experiment and some conclusions on the effectiveness of these blockage mitigation techniques.

  17. SERIES - Satellite Emission Range Inferred Earth Surveying

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.; Spitzmesser, D. J.; Buennagel, L. A.

    1983-01-01

    The Satellite Emission Range Inferred Earth Surveying (SERIES) concept is based on the utilization of NAVSTAR Global Positioning System (GPS) radio transmissions without any satellite modifications and in a totally passive mode. The SERIES stations are equipped with lightweight 1.5 m diameter dish antennas mounted on trailers. A series baseline measurement accuracy demonstration is considered, taking into account a 100 meter baseline estimation from approximately one hour of differential Doppler data. It is planned to conduct the next phase of experiments on a 150 m baseline. Attention is given to details regarding future baseline measurement accuracy demonstrations, aspects of ionospheric calibration in connection with subdecimeter baseline accuracy requirements of geodesy, and advantages related to the use of the differential Doppler or pseudoranging mode.

  18. Radio frequency interference mitigation in radio astronomy

    NASA Astrophysics Data System (ADS)

    Boonstra, Albert-Jan

    2005-12-01

    The next generation of radio telescopes is expected to be one to two orders of magnitude more sensitive than the current generation. Examples of such new telescopes are the Low Frequency Array (LOFAR), currently under construction in the Netherlands, and the Square Kilometer Array (SKA), currently in a concept study phase. Another trend is that technological advances in the fields of electronics and communications systems have led to a vast increase in radio communication applications and systems, and also to an increasing demand for radio spectrum. These two trends, more sensitive telescopes and a much denser spectrum use, imply that radio astronomy will become more vulnerable to interference from radio transmitters. Although protection criteria exist for radio astronomy, it becomes increasingly difficult to keep the radio astronomy frequency bands free from interference. In order to mitigate interference in radio astronomical data, filtering techniques can be used. In this thesis, modern array signal processing techniques have been applied to narrow-band multichannel interference detection and excision, and to narrow-band spatial interference filtering. By investigating the subspace structure of the telescope array output covariance matrices, new results were found, such as upper limits on interference residuals after excision and spatial filtering. The effect of bandwidth, extendedness of the interfering sources, and multipath effects on the detection and spatial filter effectiveness were studied as well. The advantage of a multichannel approach over a single telescope approach was demonstrated by using experimental data from the Westerbork Synthesis Radio Telescope (WSRT). As the performance of mitigation algorithms can be improved by calibration of the telescope gains and noise powers, calibration algorithms were developed. These algorithms were verified both for single and dual polarised arrays. Finally, a LOFAR interference mitigation strategy was developed.

  19. Static Inflation Test of 135 foot satellite

    NASA Technical Reports Server (NTRS)

    1961-01-01

    Series showing inflation test of Echo I in Weeksville, N.C. L61-4603 shows Echo team, Wm. J. O'Sullivan is tallest, in center, Walter Bressette is to his left. (this inflation took place in 1958, LaRC copied the photos from Schjendahl Co. in 1961.) L61-4597: ECHO 1 was America's first passive communications satellite, a 100 foot diameter aluminized Mylar plastic balloon that reflected radio signals beyond Earth's curvature. Photograph published in Winds of Change, 75th Anniversary NASA publication (page 79), by James Schultz.

  20. OECD Principles of Corporate Governance

    NSDL National Science Digital Library

    The "Organisation for Economic Co-operation and Development Principles of Corporate Governance" sets out a structure for directing and controlling corporate businesses. This document (html or .pdf) consists of five sections detailing the principles: "The rights of shareholders," "The equitable treatment of shareholders," "The role of stakeholders in corporate governance," "Disclosure and transparency," and "The responsibilities of the board," as well as annotations for each of the sections. Be sure to visit the OECD Principles of Corporate Governance Q&A page, linked at the top of the page.

  1. GSM\\/Satellite Issues

    Microsoft Academic Search

    Heikki Einola

    In this presentation, the mobile satellite service (MSS) is regarded as complementary to the corresponding terrestrial systems.\\u000a The MSS may offer an outdoor service extension to the terrestrial mobile systems. This can be achieved with appropriate integration\\u000a of the satellites with the terrestrial system. This chapter considers the integration of mobile satellites into the GSM system.\\u000a On one hand, the

  2. Meteorological satellite accomplishments

    NASA Technical Reports Server (NTRS)

    Allison, L. J.; Arking, A.; Bandeen, W. R.; Shenk, W. E.; Wexler, R.

    1975-01-01

    Meteorological satellites include experimental satellites operated by NASA and operational satellites operated by the National Oceanic and Atmospheric Administration (NOAA). The operational system currently provides pictures of the entire globe, temperature measurements throughout the world, and wind measurements in selected parts of the Atlantic and Pacific oceans. Aspects of vertical sounding are discussed along with questions of parameter extraction technique development, macroscale phenomena, the heat budget of the earth-atmosphere system and the climate, and studies of ocean surface and hydrology.

  3. Sputnik 1 and the First Satellite Ionospheric Experiment

    NASA Astrophysics Data System (ADS)

    Sinelnikov, Vyacheslav; Kuznetsov, Vladimir; Alpert, Svetlana

    The world's first scientific space experiment was carried out in 1957 during the flight of the first Artificial Earth Satellite (AES) - Sputnik 1. It was an ionospheric experiment performed at IZMIRAN under the direction of Prof. Ya.L.Alpert (1911-2010). The sunrise and sunset variations in the AES radio signal were recorded in order to determine the distribution of electron density in the topside ionosphere (above the maximum). The experiment demonstrated the capabilities of the satellite radio beacon method, which is now very important and widely used for studying the ionosphere. Our report submitted to the COSPAR General Assembly in Russia describes the history and results of that experiment, as well as some other contributions by Ya.L.Alpert to ionospheric research. Yakov L.Alpert was one of the most famous and influential radiophysicists of his time, the author of many fundamental studies and of a number of classic books on the theory of propagation of electromagnetic waves, interaction of artificial bodies with ionospheric plasmas, ionospheric radio scattering, and the use of satellite radio beacon methods for studying the ionosphere.

  4. Yakov Alpert: Sputnik-1 and the first satellite ionospheric experiment

    NASA Astrophysics Data System (ADS)

    Kuznetsov, V. D.; Sinelnikov, V. M.; Alpert, S. N.

    2015-06-01

    The world first scientific space experiment was carried out in 1957 during the flight of the First Artificial Earth Satellite (AES) - Sputnik-1. It was an ionospheric experiment performed at IZMIRAN under the direction of Prof. Ya.L. Alpert (1911-2010). The sunrise and sunset variations in the AES radio signal were recorded to determine the distribution of electron density in the topside ionosphere (above the maximum). The experiment demonstrated the capabilities of the satellite radio beacon method, which is now very important and widely used for studying the ionosphere. The paper describes the history and results of that experiment as well as the contribution of Ya.L. Alpert to ionospheric research. Ya.L. Alpert was one of the most famous and influential radiophysicists, the author of many fundamental studies and a number of classic books on the theory of propagation of electromagnetic waves, interaction of artificial bodies with ionospheric plasma, ionospheric radio scattering, and the use of satellite radio beacon methods for studying the ionosphere. We give in the paper some extracts from Ya.L. Alpert's research notes. They include the history of the publication of the results from recordings of the Sputnik-1 transmitter signals, and described the method of data analysis. The first scientific publication based on Sputnik-1 data is given in the abbreviated summary. At the end of the paper there is an outline of Ya.L. Alpert's scientific biography.

  5. Commercial communications satellite survivability

    NASA Astrophysics Data System (ADS)

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

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

  6. Satellite system survivability

    NASA Astrophysics Data System (ADS)

    Shelton, F. H.

    Present U.S. military capability relies heavily on Earth satellites to maintain connectivity. The essential nature of these satellite systems has made them tempting targets to nuclear attack in wartime. The author reviews U.S. history in high-altitude nuclear device testing and nuclear effects testing on satellies, events in which he directly participated. Physics of the production of nuclear enhanced high-altitude electron belts are reviewed. The author discusses primary affects of the enhanced environment on satellite components. A glimpse into future satellite hardening reveals measures against developing directed energy weapons.

  7. Equalizers for communications satellites

    E-print Network

    Fay, Leon

    2008-01-01

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

  8. Weather satellite deactivated

    NASA Astrophysics Data System (ADS)

    Katzoff, Judith A.

    NOAA 8, the polar-orbiting weather satellite that was revived last May after tumbling in its orbit for 11 months (Eos, July 2, 1985, p. 527), recently suffered additional setbacks and has been “deactivated” by the National Oceanic and Atmospheric Administration (NOAA). The satellite's only working oscillator faltered and caused episodes of tumbling in September, November, and December 1985, according to Gary K. Davis, manager of NOAA's satellite operations control center in Suitland, Md. In addition, the episode that began December 30 apparently was accompanied by the rupture of a damaged battery, sending what seem to be pieces of the battery's thermal blankets and shields into orbits near the satellite.

  9. Satellite-aided land mobile communications system implementation considerations

    NASA Technical Reports Server (NTRS)

    Leroy, B. E.

    1982-01-01

    It was proposed that a satellite-based land mobile radio system could effectively extend the terrestrial cellular mobile system into rural and remote areas. The market, technical and economic feasibility for such a system is studied. Some of the aspects of implementing an operational mobile-satellite system are discussed. In particular, two key factors in implementation are examined: (1) bandwidth requirements; and (2) frequency sharing. Bandwidth requirements are derived based on the satellite antenna requirements, modulation characteristics and numbers of subscribers. Design trade-offs for the satellite system and potential implementation scenarios are identified. Frequency sharing is examined from a power flux density and modulation viewpoint. Previously announced in STAR as N82-25290

  10. MIMO over Satellite: A Review

    Microsoft Academic Search

    Pantelis-Daniel Arapoglou; Konstantinos Liolis; Massimo Bertinelli; Athanasios Panagopoulos; Panayotis Cottis; Riccardo De Gaudenzi

    2011-01-01

    The present article carries out a review of MIMO- based techniques that have been recently proposed for satellite communications. Due to the plethora of MIMO interpretations in terrestrial systems and the particularities of satellite communica- tions, this review is built on two pillars, namely fixed satellite and mobile satellite. Special attention is given to the characteristics of the satellite channel,

  11. Hill stability of satellite orbits

    Microsoft Academic Search

    V. V. Markellos; A. E. Roy

    1981-01-01

    Szebehely's criterion for Hill stability of satellites is derived from Hill's problem and a more exact result is obtained. Direct, Hill stable, circular satellites can exist almost twice as far from the planet as retrograde satellites. For direct satellites the new result agrees with Kuiper's empirical estimate that such satellites are stable up to a distance of half the “radius

  12. 12 CFR 5.42 - Corporate title.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Corporate title. 5.42 Section 5.42...RULES, POLICIES, AND PROCEDURES FOR CORPORATE ACTIVITIES Other Changes in Activities and Operations § 5.42 Corporate title. (a) Authority....

  13. 27 CFR 24.149 - Corporate surety.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Corporate surety. 24.149 Section 24...Consents of Surety § 24.149 Corporate surety. (a) Surety bonds...this part may be obtained only from corporate sureties which hold...

  14. 39 CFR 221.4 - Corporate officers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Corporate officers. 221.4 Section 221... GENERAL ORGANIZATION § 221.4 Corporate officers. The Board of Governors determines the number of corporate officers and appoints the...

  15. 27 CFR 19.233 - Corporate surety.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Corporate surety. 19.233 Section 19...Consents of Surety § 19.233 Corporate surety. (a) Surety bonds required...this part may be given only with corporate sureties holding...

  16. 27 CFR 28.52 - Corporate surety.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Corporate surety. 28.52 Section 28...Consents of Surety § 28.52 Corporate surety. (a) Surety bonds required...this part may be given only with corporate sureties holding...

  17. 27 CFR 26.62 - Corporate surety.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Corporate surety. 26.62 Section 26.62...in Puerto Rico Bonds § 26.62 Corporate surety. (a) Surety bonds may be given only with corporate sureties holding certificates...

  18. Corporate U. Takes the Job Training Field.

    ERIC Educational Resources Information Center

    Greenberg, Richard

    1998-01-01

    Discusses corporations such as Sears, Motorola, Saturn, and Intel that have created their own corporate universities to train and retrain their workers. Highlights Motorola, the largest of the corporate universities. (JOW)

  19. 22 CFR 96.31 - Corporate structure.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Corporate structure. 96.31 Section...UNDER THE INTERCOUNTRY ADOPTION ACT OF 2000 (IAA) Standards...and Approval Licensing and Corporate Governance § 96.31 Corporate structure. (a)...

  20. 75 FR 75648 - Corporate Credit Unions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-06

    ...proposed amendments to its rule governing corporate credit unions (corporates) contained...banks under the Federal Deposit Insurance Act and the Sarbanes-Oxley Act. The amendments require each corporate to establish an enterprise-wide...

  1. Is Sustainability Attractive for Corporate Real Estate

    E-print Network

    Paris-Sud XI, Université de

    Is Sustainability Attractive for Corporate Real Estate Decisions ? Research Center ESSEC Working Is Sustainability Attractive for Corporate Real Estate Decisions? Ingrid Nappi-Choulet Professor ESSEC BUSINESS provides an analysis of the impact of sustainable principles on corporate property decisions

  2. Assessment of Corporate Sustainability via Fuzzy Logic

    Microsoft Academic Search

    Yannis A. Phillis; Benjamin J. Davis

    2009-01-01

    Corporations interact with society and the physical and biological environment in ways that affect both sides. In this capacity,\\u000a corporations play an important role in the sustainability of a region or country. Symmetrically, a corporation’s sustainability\\u000a depends on the sustainability of its wider environment. In this paper, a multi-stage fuzzy reasoning model is presented to\\u000a assess a corporation’s sustainability. The

  3. Strategically Leveraging Corporate Social Responsibility

    Microsoft Academic Search

    Christine Vallaster; Adam Lindgreen; François Maon

    2012-01-01

    Corporate social responsibility (CSR) is changing the rules of branding but it is unclear how. While the literature offers a range of approaches seeking insight to how to manage CSR-related issues, practitioners are left in a state of confusion when having to decide on how to tackle CSR in a way that benefits both the corporate brand and society at

  4. 76 FR 68747 - Hess Corporation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-07

    ...Federal Energy Regulatory Commission [Docket No. EL12-7-000] Hess Corporation v. PJM Interconnection, L.L.C.; Notice of...and Procedures, 18 CFR 385.207(a)(2) and 385.212, Hess Corporation (Complainant) filed a Petition for...

  5. Will Corporate Income Taxation Survive?

    Microsoft Academic Search

    Ruud A. De Mooij

    2005-01-01

    This paper explores the future of corporate income taxation, with special reference to the Netherlands. We review the empirical literature on a variety of distortions and arbitrage opportunities and pay due attention to effect sizes. An attempt is made to compare the size of various distortions in terms of the ex-post revenue impact of a corporate tax reduction. Thus, we

  6. Corporate governance and executive compensation

    Microsoft Academic Search

    Martin J. Conyon

    1997-01-01

    This paper examines the impact of corporate governance innovations on top director compensation in a sample of 213 large UK companies between 1988 and 1993. An enabling factor in the analysis is access to survey data on recent corporate governance changes in UK companies. The paper finds that director compensation and current shareholder returns are positively correlated. However, in line

  7. Corporate Ownership Around the World

    Microsoft Academic Search

    Rafael La Porta; Florencio Lopez-De-Silanes; Andrei Shleifer

    1999-01-01

    We use data on ownership structures of large corporations in 27 wealthy economies to identify the ultimate controlling shareholders of these firms. We find that, except in economies with very good shareholder protection, relatively few of these firms are widely held, in contrast to Berle and Means's image of ownership of the modern corporation. Rather, these firms are typically controlled

  8. Corporate Ownership Around the World

    Microsoft Academic Search

    Rafael La Porta; Florencio Lopez-de-Silanes; Andrei Shleifer

    1998-01-01

    We present data on ownership structures of large corporations in 27 wealthy economies, making an effort to identify ultimate controlling shareholders of these firms. We find that, except in economies with very good shareholder protection, relatively few of these firms are widely-held, in contrast to the Berle and Means image of ownership of the modern corporation. Rather, these firms are

  9. Corporate Governance and National Development

    Microsoft Academic Search

    Charles P. Oman

    2001-01-01

    Corporate governance matters for national development. Case studies of Argentina, Brazil, Chile, China, India, Malaysia and South Africa suggest that it has a role of growing importance to play in helping to increase the flow of financial capital to firms in developing countries. Equally important are the potential benefits of improved corporate governance for overcoming barriers, including the actions of

  10. Corporal Punishment and Child Adjustment

    ERIC Educational Resources Information Center

    Aucoin, Katherine J.; Frick, Paul J.; Bodin, S. Doug

    2006-01-01

    The association between corporal punishment and children's emotional and behavioral functioning was studied in a sample of 98 non-referred children with a mean age of 12.35 (SD=1.72) recruited from two school systems in the southeastern United States. Children were divided into those who had experienced no corporal punishment over approximately a…

  11. The Banning of Corporal Punishment.

    ERIC Educational Resources Information Center

    Cryan, John R.

    1995-01-01

    Presents the 1985 resolution of the Association for Childhood Education International (ACEI) for participation in the interdisciplinary effort to ban corporal punishment. Discusses distinctions between discipline and child abuse. Reports medical and psychological effects of physical punishment, and relationships between school corporal punishment…

  12. Corporal Punishment in the Schools.

    ERIC Educational Resources Information Center

    Review and Evaluation Bulletins, 1981

    1981-01-01

    A continuing dichotomy in public opinion concerning the use of corporal punishment in Canadian schools provided the impetus for this paper, which includes a review of the relevant literature. Morality issues surrounding corporal punishment are discussed and public opinion data are exerpted from the Provincial Review of School Disciplinary Policy…

  13. Corporate Governance in Financial Institutions

    Microsoft Academic Search

    Spyros G. Stavrinakis; Christian Harm; David T. Llewellyn; Bridget Gandy; Peter Shaw; Peter Tebbutt; Mark Young

    On 29th - 30th March 2007, SUERF and the Central Bank of Cyprus jointly organized a Seminar: Corporate Governance in Financial Institutions. The papers in the present publication are based on a sample of the presentations at the Seminar. Together, the papers illuminate a number of key issues in corporate governance in a variety of financial firms. In the first

  14. French by Satellite.

    ERIC Educational Resources Information Center

    Rose, Russell G.

    Satellite television is proposed as a useful source of authentic materials for French language instruction at the college level. It is argued that this medium illustrates to students that the language is used in a wide variety of everyday situations and contexts. The discussion begins with a brief description of common satellite technology,…

  15. 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)

  16. Satellite Teleconference Final Report.

    ERIC Educational Resources Information Center

    Elgin Community Coll., IL.

    The vocational education satellite teleconference project accomplished two goals: (1) identified, acquired, copied, and distributed to the Illinois Vocational Curriculum Center 100 marketing or training videotapes for staff development and classroom use; and (2) provided from 15-25 variable time (1- to 3-hour) satellite teleconferences in four…

  17. Interkosmos laser satellite rangefinder

    Microsoft Academic Search

    V. A. Yegorov

    1978-01-01

    A laser satellite rangefinder, with the capability of measuring distances up to 3,000 km with an accuracy to plus or minus 5 m was developed. The instrument includes: a pointing mechanism, photoelectric detector, time interval counter and a standard time service system. Five copies of this instrument have already been fabricated and are now operating at the artificial earth satellite

  18. Mobile satellite communications

    Microsoft Academic Search

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

    1994-01-01

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

  19. Efficient Packet Satellite Communications

    Microsoft Academic Search

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

    1979-01-01

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

  20. Audio direct broadcast satellites

    NASA Technical Reports Server (NTRS)

    Miller, J. E.

    1983-01-01

    Satellite sound broadcasting is, as the name implies, the use of satellite techniques and technology to broadcast directly from space to low-cost, consumer-quality receivers the types of sound programs commonly received in the AM and FM broadcast bands. It would be a ubiquitous service available to the general public in the home, in the car, and out in the open.

  1. ASTER's Satellite Image Gallery

    NSDL National Science Digital Library

    NASA Jet Propulsion Laboratory

    This site provides access to satellite images acquired by NASA's Advanced Spaceborne Thermal Emission and Reflection Radiometer satellite. The images are sorted into eight categories: Archeology, Cities, Geology, Hydrology, Land Use, Natural Hazards, and Volcanoes. Users can also view the most popular images and the most recent additions to the gallery.

  2. Disk-satellite interactions

    Microsoft Academic Search

    P. Goldreich; S. Tremaine

    1980-01-01

    The rate at which angular momentum and energy are transferred between a disk and a satellite which orbit a central mass is calculated. It is shown that the angular momentum and energy transfer at Lindblad resonances tends to increase the satellite's orbit to lowest order in eccentricity, whereas the transfer at corotation resonances tends to decrease it. The results are

  3. A Small Radio Telescope for Instructional Purposes

    NASA Astrophysics Data System (ADS)

    Spangler, S. R.; Wurster, J. E.; Nellermoe, B. L.

    1996-12-01

    Radio astronomers nowadays have a number of excellent instruments to choose from for their research projects, such as the VLA, VLBA, Arecibo,etc. However, these instruments do not readily furnish the opportunity for student instruction in the technical aspects of radio astronomy that was available twenty five years ago or more. Such experience can in part be provided by small dedicated telescopes at universities. Such a radiotelescope has been installed at the University of Iowa. A commercial 4.5 meter satellite TV antenna has been modified to work as a radiotelescope. The radio telescope operates as a transit instrument, with computer control of elevation pointing. Working receivers exist at 5.0 and 1.4 GHz. Components exist for construction of receivers at 610 MHz and 15.0 GHz. Observations to date have been made of the Sun, Moon, Crab Nebula, and galactic HI. We have recently installed a mechanical switch in the 5 GHz front end, built switching electronics, and written a Labview virtual instrument to provide a Dicke radiometer. In the immediate future we plan to use this instrument to repeat the determination of the 5.0 GHz radio phase function of the Moon. Our presentation will include information on commercial sources of critical components for the system, such as low loss RF cables, low insertion loss mechanical switches, low noise amplifiers, etc.

  4. Optimization of Satellite Constellation Reconfiguration

    E-print Network

    Optimization of Satellite Constellation Reconfiguration by Uriel Scialom Submitted Students #12;2 #12;Optimization of Satellite Constellation Reconfiguration by Uriel Scialom Submitted for the degree of Master of Science in Aeronautics and Astronautics Abstract Traditional satellite constellation

  5. US Radio Broadcasting Past

    NSDL National Science Digital Library

    White, Thomas W.

    Thomas H. White discusses the history of United States radio in detail from the late 1800�s to the 1940�s in this informative site featuring a compilation of materials and articles. The site features 24 different sections arranged by title and year for users to browse, each section allows the user to discover the beginnings of radio in the United States. Sections include some that outline the changes of radio in relation to U.S. history, including but not limited to the World Wars, as well as discussions of big business and radio, and early government regulation to name only a few. For anyone interested in the history of radio and how radio got to where it is today, this site is an excellent resource.

  6. American RadioWorks

    NSDL National Science Digital Library

    Radio documentaries have been around almost since the beginning of regularly scheduled radio programming, but not all are created equal (or with great aplomb), and the American Radio Works is certainly one of the finer documentary production units in the field. Based at Minnesota Public Radio in St. Paul, Minnesota, Radio Works' primary themes include public affairs documentaries on major social and economic issues, investigative reporting, and the Living History series, which seeks to document the 20th century American experience "through the lives of those who witnessed it." The web-browsing public will be glad to know that all of the radio projects are available online here, and can be listened to in their entirety. Visitors can listen to close to 40 of their productions, including their most recent production which deals with the extensive phone conversations recorded by Presidents Johnson, Kennedy, and Nixon during their terms in the White House

  7. Experimental Satellite Quantum Communications

    E-print Network

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

    2014-06-16

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

  8. The software radio development system

    Microsoft Academic Search

    S. P. Reichhart; B. Youmans; R. Dygert

    1999-01-01

    This article focuses on the effort to advance the field of software reprogrammable radios and the building of a software radio testbed to develop advanced radio waveforms and techniques. The Air Force Research Laboratory has performed research on software reprogrammable radios since 1990 when the SPEAKeasy program was begun to determine if a multiband, multimode software radio was technically feasible.

  9. Radio-Locator

    NSDL National Science Digital Library

    Radio-Locator is a comprehensive database of radio stations throughout the United States and Canada. Stations can be searched by location and format, or even more specifically with the site's advanced search. Users can even search for vacant frequencies on the dial. The bulk of their information come from the FCC's public databases, but is also updated and corrected. Radio-Locator also provides links to individual stations website and internet streams if available.

  10. Radio Link Frequency Assignment

    Microsoft Academic Search

    Bertrand Cabon; Simon De Givry; Lionel Lobjois; Thomas Schiex; Joost P. Warners

    1999-01-01

    Abstract: The problem of radio frequency assignment is to provide communication channelsfrom limited spectral resources whilst keeping to a minimum the interference suered by thosewhishing to communicate in a given radio communication network. This problem is a combinatorial(NP-hard) optimization problem. In 1993, the CELAR (the French \\\\Centre d'Electronique del'Armement") built a suite of simplied versions of Radio Link Frequency Assignment

  11. Some radio meteor news

    NASA Astrophysics Data System (ADS)

    Rault, Jean-Louis

    2013-01-01

    Radio meteor observing for astronomy purposes is still alive, despite the fact that traditional TV transmitters used for decades tend to disappear. Radio observers are now starting to develop their own dedicated transmitters, and are using new kinds of transmitters, such as military and radio-navigation systems to continue their studies. Encouraging results are also obtained in the aeronomy/geophysics domain when searching for evidence of modifications of the Earth/ionosphere waveguide by discrete ionized meteor trails.

  12. Dominion Radio Astrophysical Observatory

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The Dominion Radio Astrophysical Observatory began operating in 1959, and joined the NATIONAL RESEARCH COUNCIL in 1970. It became part of the Herzberg Institute of Astrophysics in 1975. The site near Penticton, BC has a 26 m radio telescope, a seven-antenna synthesis telescope on a 600 m baseline and two telescopes dedicated to monitoring the solar radio flux at 10.7 cm. This part of the Institu...

  13. Mechanically-Steered, Mobile Satellite-Tracking Antenna

    NASA Technical Reports Server (NTRS)

    Bell, D. J.; Berner, J. B.; Jamnejad, V.; Woo, K. E.

    1990-01-01

    Signal from satellite tracked in moving vehicle. L-band, mechanically-steered, medium-gain antenna part of prototype radio equipment mounted in vehicle to demonstrate concept of land-mobile/satellite communication system. Provides such services as mobile telephone, voice or alphanumeric dispatch, paging, position-location information, and low-rate data transmission, for users within continental United States and Alaska. Antenna rotated mechanically until it finds direction from which maximum signal comes. Rate sensors provide inertial frame of reference during acquisition, so antenna locks onto signal even when vehicle turning.

  14. Direct/community broadcast projects using space satellites

    NASA Technical Reports Server (NTRS)

    Frutkin, A. W.

    1975-01-01

    A review is presented of direct/community broadcast projects which are currently in preparation in India, Canada, and Japan. It is shown that the satellite broadcast experiments involved are conducted for practical domestic reasons. The broadcast activities in all three projects will not reach other countries' TV receivers unless those countries take deliberate steps to enable themselves to receive such broadcasts. It is pointed out that for technological reasons problems of intrusion and interference connected with the use of satellites in broadcast operations may be much easier to handle than similar problems related to conventional radio broadcasting.

  15. TIDs over Tucuman by GPS radio interferometry

    NASA Astrophysics Data System (ADS)

    Rios, Victor

    This paper presents some results investigating the new possibilities of radio interferometry of Travelling Ionospheric Disturbances (TIDs) that are based on exploiting standard measurements of transionospheric radio signal characteristics and coordinate-time measurements using dual-frequency multichannel receivers of the Global Positioning System (GPS). We consider some methods of reconstructing TID characteristics, which were used in classical radio interferometry and can be useful when processing GPS data. Let us consider an interferometer that consist of three receivers, installed at vertexes of triangle on Tucuman (26°49' 00" S ;65°13' 00" W) with sides oriented to the north and east. A Statistical Angle-of-arrival and Doppler Method for GPS radio interferometry is proposed for determining the characteristics of the TIDs dynamics by measuring variations of GPS phase derivatives with respect to time and spatial coordinates. These data are used to calculate corresponding values of the velocity vector, in view of a correction for satellite motions based on the current information available regarding the angular coordinates of the satellites. Our findings show that : a) We learnt that Gravity Waves (GW) can be measured with a system of 3 closely located GPS receivers, b) It is possible to detect the angle of arrival, velocity, and period of the GWs, c) Attention has to be paid to cases when there are TEC depletions as they can be mistaken by GWs, d) To avoid a false detection is possible to use a spectral analysis that will help us differentiate between perturbations that are moving with different velocities.

  16. STEM on the radio

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2011-10-01

    Looking for an Internet radio station focusing on programing about science, technology, engineering, and math (STEM)? The U.S. National Science Foundation (NSF) announced on 26 September the launch of Science360 Radio, which it says is the first Internet radio stream dedicated to STEM programing. Science360 includes more than 100 radio shows and podcasts that are available on the Web as well as on iPhone and Android devices. The shows originate from a variety of sources, including NSF, other U.S. government agencies, science organizations, universities, and media outlets. For more information, see http://science360.gov/files/.

  17. Satellite Services Workshop, Volume 1

    NASA Technical Reports Server (NTRS)

    1982-01-01

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

  18. Satellite broadcasting - Capabilities for public service

    NASA Technical Reports Server (NTRS)

    Marsten, R. B.

    1975-01-01

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

  19. Rural Community Assistance Corporation

    NSDL National Science Digital Library

    Founded in 1978, the Rural Community Assistance Corporation (RCAC) is dedicated â??to assisting rural communities in achieving their goals and visions by providing training, technical assistance and access to resources.â? Their work is primarily focused on work in the 13 Western states and for communities with populations under 50,000. The homepage is quite inviting, and allows users to peruse a list of upcoming events and support activities sponsored by the RCAC or other like-minded organizations. Persons seeking assistance or working on behalf of such communities will appreciate information from the homepage on such programs as housing, financing, and rural infrastructure development initiatives. The publications area of the site is quite strong, especially considering that visitors can study over ten newsletters here, including Alaska Anew, which details specifically with the search for finding solutions to the solid waste problem in Alaska.

  20. Design considerations for data networks via satellite systems

    NASA Astrophysics Data System (ADS)

    Hoversten, E. V.

    The design of satellite data-communications systems is reviewed from a systems perspective, emphasizing the role of baseband functions. The basic types of services likely to be required in the immediate future and the traffic characteristics they imply are examined, and the need for an integrated design approach is stressed. The satellite-link equations are presented, and their implications for system design are discussed. Topics considered include propagation effects; antenna size; choice of multiple-access technique; demand assignment and channel multiplication; the interaction of switching, channel multiplication, voice processing, and DAMA; satellite delay; coding; encryption; and multitransponder networks. The typical basic design parameters of a data-collection/acquisition network, a small corporate network, and a large common-user digital network are listed in tables and compared. Drawings, block diagrams, and graphs of important physical relationships are provided.

  1. Swedish small satellites

    NASA Astrophysics Data System (ADS)

    Lundahl, K.; von Scheele, F.

    2004-11-01

    In 1986 the first Swedish small satellite VIKING was launched on the Ariane 1 rocket together with the French remote sensing satellite SPOT-1. This paper describes the development of Swedish small satellites in an international framework. The satellites have delivered excellent scientific data to a low cost by using e.g. streamlined project organisations, competitive procurement programs and piggy-back launch opportunities. The first micro satellite Astrid-1 was launched in January 1995 and was followed by the launch of Astrid-2 in December 1998. The capable Odin small satellite was launched in February 2001. SSC was also contracted for ESA's SMART-1 probe destined to the Moon. SMART-1, launched in September 2003, is used for both research and as a technology demonstrator for future projects. Future proposed projects include micro and small satellites for climate research as the Atmosphere and Climate Explorer Plus (ACE+), the Stratosphere-Troposphere Exchange And climate Monitor (STEAM) and PRISMA, a technology demonstrator for formation flying, new propulsion system and commercial development methods.

  2. MEMOS - Mars Environment Monitoring Satellite

    NASA Astrophysics Data System (ADS)

    Ott, T.; Barabash, S.; von Schéele, F.; Clacey, E.; Pokrupa, N.

    2007-08-01

    The Swedish Institute of Space Physics (IRF) in cooperation with the Swedish Space Corporation (SSC) has conducted first studies on a Mars Environment Monitoring Satellite (MEMOS). The MEMOS microsatellite (mass < 20 kg) will accommodate four scientific instruments: solar EUV/UV monitor (SEM), solar wind monitor (SWIM), magnetometer (MAG) and radiation environment monitor (REM). The payload monitors the solar conditions at Mars and characterizes the Mars environment to support other missions and science investigations. Monitoring of the solar wind parameters (velocity, density, and field) is the key for any aeronomy and solar wind interaction mission at Mars. The solar EUV / UV (HeII 30.4 nm and HII 121.6 nm) flux monitoring is required for upper atmosphere / ionosphere studies. The radiation environment monitoring is needed to study space weather effects on the near-Mars environment as well as for the preparations for man-flights. MEMOS follows the design philosophy of a detached and autonomously flying instrument for achieving the mentioned objectives. It is intended to be carried "piggy-back" to Mars on a suitable mission. Potential missions are: ESA Mars orbiters within the NEXT or Cosmic Vision programs, NASA Mars orbiters, national / bilateral Mars missions. At Mars MEMOS is separated from its carrier (parent satellite) via the release mechanism implemented in the dual formation flight mission PRISMA. The separation will take place during the orbit insertion scenario of the parent satellite at Mars thus placing MEMOS in a highly elliptical orbit guarantying sufficient observation time in the solar wind. In orbit MEMOS will autonomously detumble and spin-up to ~1 rpm for reasons of stabilization and to fulfill instrument requirements. Such a low spin-rate is sufficient for a required inertial pointing accuracy of 2.5° because of the small external disturbance torques (< 10-7 Nm) predominant at Mars responsible for nutation and precession of the spin-axis. The advances in micropropulsion systems providing ?NmN adjustable thrust levels and reducing the dry mass to ~2 kg respectively are key factors in keeping the microsatellite stabilized and sun-pointed without stressing the mass budget. The low thrust level enables precise and active nutation damping. Moreover the system offers the possibility of implementing active orbit control or formation flight demonstrations at Mars. Attitude will be determined on-board with an accuracy < 1.0° using miniaturized Horizon Crossing Indicators, a two-axis sun sensor and in support accelerometers and gyroscopes based on MEMS-technology. TM/TC will be relayed via the parent satellite in the UHF frequency range. Therefore the Electra Lite (ELT) Proximity-1 transceiver will autonomously communicate with the parent satellite at inter-satellite ranges < 10 000 km featuring adaptive bit rates > 2 kbit/s. The transceiver also implements a coherent transponding mode for orbit determination through two-way Doppler ranging between the parent satellite and MEMOS. In addition ELT is compatible with a future Martian communication and navigation network pursued by NASA, which could be taken advantage of in the future for relaying data or performing ranging via other satellites part of the network. A system design driver for inter-satellite communication at Mars is the high demand of power. This leads to a disk-shape and thus easy to accommodate spacecraft configuration of MEMOS comprising a single sun-pointing solar array favourable in terms of power and spin stability. Multi-junction solar cells, which currently have an efficiency of ~29% under laboratory conditions are a key factor to keep MEMOS solar array area of ~1.15 m2 small compared to the worst case system power requirements of ~105 W. During eclipse periods high-efficient Li-ion batteries (6 x 20 Wh) will ensure power supply. The spacecraft and payload design will incorporate new technology developments such as autonomous navigation, MicroElectroMechanical Systems MEMS, Micro- Opto-ElectroMechanical Sys

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  4. Satellite selection criteria

    NASA Technical Reports Server (NTRS)

    Klosko, S. M.; Lerch, F. J.; Wagner, C. A.; Colombo, O. L.

    1985-01-01

    An attempt is made to give relative weight to the factors which influence the selection of satellites for inclusion in the gravity modeling problem associated with TOPEX. This scheme gives both credits and demerits in this process and does so in a relative sense stressing characteristics which are most important while factoring in the major problems associated with some satellites. Selection factors include a data value assessment, uniqueness of orbital characteristics, satellite similarity to TOPEX sensitivities, apsidal coverage, nonconservative force influences, and sensitivity to the anomalous field.

  5. Remote Sensing Using Satellites

    NSDL National Science Digital Library

    Kathryn Ginger

    1998-06-30

    This website was developed for undergraduate students enrolled in an introductory earth or atmospheric science course. It is designed to supplement lecture and textbooks. Its goal is to make you a better consumer of weather information by providing dynamic graphics, animations, and science content about remote sensing, visible and infrared satellite imagery, and hurricanes. As part of the module, you will apply what you've learned by exploring recent hurricanes through satellite imagery. When you have completed this module, you should be able to view satellite imagery in a typical weather forecast on TV or the Web and recognize the importance of some features.

  6. Satellite Tracking Threatened Species

    NSDL National Science Digital Library

    The Patuxent Wildlife Research Center and NASA's Goddard Space Flight Center have combined forces to produce this Website on the use of satellite tracking to monitor migration routes of endangered birds. Targeting the general public, the site introduces readers to satellite tracking (using Direct Readout technology), offers animations of bird flight paths (see the section entitled Birdtracks), and gives additional information on birds (in the Bird Data Archives, select a bird and watch its flight path through time). While bird information is limited to several larger species (due to the size/weight of attached transmitters), the resource serves as a useful information base for anyone wishing to learn more about satellite tracking.

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

    NASA Technical Reports Server (NTRS)

    Freibaum, Jerry

    1990-01-01

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

  8. Enhanced performance of the Westinghouse Series 1000 Mobile Satellite Telephone System

    NASA Technical Reports Server (NTRS)

    Martinson, Richard E.

    1995-01-01

    The Westinghouse Series 1000 Mobile Satellite Telephone System is designed for land mobile, maritime, and fixed site land applications. The product currently operates on the Optus Mobilesat system in Australia and will operate on American Mobile Satellite Corporation's (AMSC) Skycell service in the U.S. and TMI Communications' (TMIC) MSAT service in Canada. The architecture allows the same transceiver electronics to be used for diverse mobile applications. Advanced antenna designs have made land mobile satellite communications a reality. This paper details the unique high performance product and its configuration for the vehicle mounted land mobile application.

  9. Tax aspects of collapsible corporations 

    E-print Network

    Lehmann, Herman August

    1960-01-01

    construction. 30 T. C. 969. Ibid. 28 A further interpretation of "with a view to" was made in Burge v. 12 Commissioner. Burge in his testimony, conterded that he did not have the requisite intent of selling or exchanging his stock, but that he intended.... was a principal corporate activity even if the "view to" collapse was not the principal corporate objective when the corporation was formed or availed of. In Burge v. Commissioner the taxpayer contended that principally modified "with a view to...

  10. Stabilized radio frequency quadrupole

    DOEpatents

    Lancaster, Henry D. (Orinda, CA); Fugitt, Jock A. (Berkeley, CA); Howard, Donald R. (Danville, CA)

    1984-01-01

    A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

  11. Radio Astronomy for Amateurs

    Microsoft Academic Search

    N. Quinn

    2003-01-01

    Karl Jansky is considered the father of RADIOASTRONOMY. During the 1930s, Jansky worked for the Bell Telephone Laboratories studying the origin of static noise from thunderstorms. During the course of this work he discovered that some signals had an extraterrestrial origin. However, it was Grote Reber, a professional radio engineer and radio amateur, who carried out further investigations. In 1937...

  12. Radio Astronomy for Amateurs

    NASA Astrophysics Data System (ADS)

    Quinn, N.; Murdin, P.

    2003-04-01

    Karl Jansky is considered the father of RADIOASTRONOMY. During the 1930s, Jansky worked for the Bell Telephone Laboratories studying the origin of static noise from thunderstorms. During the course of this work he discovered that some signals had an extraterrestrial origin. However, it was Grote Reber, a professional radio engineer and radio amateur, who carried out further investigations. In 1937...

  13. Radio spectrum surveillance station

    Microsoft Academic Search

    D. R. Hersey

    1979-01-01

    The paper presents a general and functional description of a low-cost surveillance station designed as the first phase of NASA's program to develop a radio spectrum surveillance capability for deep space stations for identifying radio frequency interference sources. The station described has identified several particular interferences and is yielding spectral signature data which, after cataloging, will serve as a library

  14. The Radio Transient Sky

    NASA Astrophysics Data System (ADS)

    Lazio, J.

    Radio transients are known on time scales from nanoseconds to years, from sources in the Galaxy and beyond, and with either coherent or incoherent emission mechanisms. Observations of this wide variety of sources are relevant to many of the highest profile questions in astronomy and astrophysics. As illustrations of the breadth of the radio transient sky, both coherent and incoherent radio emission has long been known from stars and stellar remnants and has informed topics ranging from stellar evolution to Galactic structure to relativistic jet dynamics to tests of fundamental physics. Coherent radio emission is now also known from brown dwarfs, and there are active programs to find similar emissions from extrasolar planets. Outside of the Galaxy, incoherent radio counterparts to supernovae, tidal disruption events, and gamma-ray bursts is well known and have contributed to topics such as understanding the cosmic star formation rate and the formation of relativistic jets. Excitingly, coherent radio bursts that appear to be at cosmological distances were recently discovered. I provide a survey of the radio transient sky, illustrating both how radio transients are part of the Hot-Wired Sky and are likely to help drive the Hot-Wiring. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  15. A refracting radio telescope

    Microsoft Academic Search

    Paul Bernhardt; A. V. da Rosa

    1977-01-01

    Observations of extraterrestrial radio sources at the lower end of the radio frequency spectrum are limited by reflection of waves from the topside ionosphere and by the large size of antenna apertures necessary for the realization of narrow beamwidths. The use of the ionosphere as a lens is considered. The lens is formed by the release of chemicals such as

  16. Radio on the Internet.

    ERIC Educational Resources Information Center

    Raeder, Aggi

    1996-01-01

    Discusses the availability of radio "cybercasts" on the Internet, either in real time or on demand. Topics include problems and opportunities, copyright issues, equipment and software needed for listening, and searchability of sites. Provides an annotated list of radio-related Uniform Resource Locators (URLs), including music, news, talk, and…

  17. The Radio Jove Project

    NASA Technical Reports Server (NTRS)

    Thieman, J. R.

    2010-01-01

    The Radio love Project is a hands-on education and outreach project in which students, or any other interested individuals or groups build a radio telescope from a kit, operate the radio telescope, transmit the resulting signals through the internet if desired, analyze the results, and share the results with others through archives or general discussions among the observers. Radio love is intended to provide an introduction to radio astronomy for the observer. The equipment allows the user to observe radio signals from Jupiter, the Sun, the galaxy, and Earth-based radiation both natural and man-made. The project was started through a NASA Director's Discretionary Fund grant more than ten years ago. it has continued to be carried out through the dedicated efforts of a group of mainly volunteers. Dearly 1500 kits have been distributed throughout the world. Participation can also be done without building a kit. Pre-built kits are available. Users can also monitor remote radio telescopes through the internet using free downloadable software available through the radiosky.com website. There have been many stories of prize-winning projects, inspirational results, collaborative efforts, etc. We continue to build the community of observers and are always open to new thoughts about how to inspire the observers to still greater involvement in the science and technology associated with Radio Jove.

  18. Stabilized radio frequency quadrupole

    DOEpatents

    Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

    1984-12-25

    Disclosed is a long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator. 5 figs.

  19. Orbit determination accuracies using satellite-to-satellite tracking

    NASA Technical Reports Server (NTRS)

    Vonbun, F. O.; Argentiero, P. D.; Schmid, P. E.

    1977-01-01

    The uncertainty in relay satellite sate is a significant error source which cannot be ignored in the reduction of satellite-to-satellite tracking data. Based on simulations and real data reductions, it is numerically impractical to use simultaneous unconstrained solutions to determine both relay and user satellite epoch states. A Bayesian or least squares estimation technique with an a priori procedure is presented which permits the adjustment of relay satellite epoch state in the reduction of satellite-to-satellite tracking data without the numerical difficulties introduced by an ill-conditioned normal matrix.

  20. Smart Radio Spectrum Management for Cognitive Radio

    E-print Network

    Bhattacharya, Partha Pratim; Gera, Rishita; Agarwal, Anjali

    2011-01-01

    Today's wireless networks are characterized by fixed spectrum assignment policy. The limited available spectrum and the inefficiency in the spectrum usage necessitate a new communication paradigm to exploit the existing wireless spectrum opportunistically. Cognitive radio is a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users. In this work, a fuzzy logic based system for spectrum management is proposed where the radio can share unused spectrum depending on some parameters like distance, signal strength, node velocity and availability of unused spectrum. The system is simulated and is found to give satisfactory results.

  1. GUST86 - An analytical ephemeris of the Uranian satellites. [General Uranus Satellite Theory

    NASA Technical Reports Server (NTRS)

    Laskar, J.; Jacobson, R. A.

    1987-01-01

    The General Uranus Satellite Theory GUST (Laskar, 1986) is used for the construction of an analytical ephemeris for the Uranian satellites. The theory is fitted against earth-based observations from 1911 to 1986, and all radio and optical data obtained during Voyager encounter with Uranus. Earth-based observations alone allow the determination of masses which are within 15 percent of the values determined by the Uranus flyby. The analysis of all the observations confirm the values of the masses obtained during the encounter (Stone and Miner, 1986) and give a complete set of dynamical parameters for the analytical theory. An analytical ephemeris, GUST86, with an estimated precision of about 100 km with respect to Uranus is obtained.

  2. Recommendations for the attachment of satellite transmitters to cranes

    USGS Publications Warehouse

    Ellis, D.H.; Howey, P.W.; Krapu, G.L.

    2001-01-01

    Recent advances in miniaturization of satellite transmitters have resulted in thumb-sized packages weighing less than 30 g. These are smaller than VHF radios routinely mounted on crane leg bands. With this development and with favorable signal reception results, there is no need for, and much to recommend against the continued use of back-pack mounts. We provide details for leg-mount attachments.

  3. 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.

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

    Microsoft Academic Search

    N. Blaunstein; Y. Cohen; M. Hayakawa

    2010-01-01

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

  5. 27 CFR 44.83 - Corporate documents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Corporate documents. 44.83 Section 44...Export Warehouse Proprietors § 44.83 Corporate documents. Every corporation...required by § 44.82, a true copy of the corporate charter or a certificate...

  6. Reforming corporate governance: redirecting the European agenda

    Microsoft Academic Search

    Erik Berglöf

    1997-01-01

    Corporate governance reform is in the air. This article warns against partial and hastily conceived interventions in complex and fragile governance arrangements. Reformers should step back and analyse the fundamental links between corporate law and corporate finance, and between corporate governance and the rest of the economic and legal system. Reform efforts should not meddle with specific ownership and control

  7. Corporal Punishment: Legalities, Realities, and Implications.

    ERIC Educational Resources Information Center

    Hinchey, Patricia H.

    2003-01-01

    Presents a quiz that will help readers determine the reliability of their own perceptions relating to corporal punishment in schools. Discusses U.S. Courts and corporal punishment, worldwide and nationwide legality, and the realities of corporal punishment in the United States. Discusses implications for what teachers can do to address corporal…

  8. The Knowledge-Productive Corporate University

    ERIC Educational Resources Information Center

    Jansink, Femke; Kwakman, Kitty; Streumer, Jan

    2005-01-01

    Purpose: In this paper the concept of knowledge production is used as a framework to study Dutch corporate universities. Knowledge production serves not simply as a desirable aim of corporate universities, as the concept also offers guidelines for the design of corporate universities. The purpose is to clarify the extent to which corporate…

  9. The Corporate Sustainability Model for Airline Business

    Microsoft Academic Search

    Ayse Kucuk Yilmaz

    The corporate sustainability subject is important challenge for airline managers in the today's risky, competitive and complex business environment. The corporate sustainability model is offered to be a suitable and effective managerial approach for the airline business. The new corporate sustainability model (CSM) is introduced as a useable way for implementation of corporate sustainability management in order to meet financial,

  10. Planetary radio lasing

    NASA Technical Reports Server (NTRS)

    Calvert, W.

    1988-01-01

    Both the Earth's auroral kilometric radiation (AKR) and Jupiter's decametric radio S-bursts are attributed to natural radio lasing. Presumably consisting of self-excited, closed-loop wave feedback oscillations between local irregularities of the source plasma density, this radio lasing is comparable to that which occurs in man-made optical lasers, although at radio, rather than optical wavelengths. As a result, it should produce a multiple discrete emission spectrum and intense, coherent beams. Recent observations of the AKR's discreteness and coherence have clearly ruled out the previous open-loop amplifier model for such emissions, and recent observations of the Jovian S-bursts have shown the expected, regularly-spaced, longitudinal laser modes. These new observations thus confirm the proposed planetary cyclotron radio lasing at both planets.

  11. A FUZZY GENETIC ALGORITHM FOR AUTOMATIC CHANNEL ASSIGNMENT FOR TACTICAL HF RADIO NETWORKS

    E-print Network

    Kaminsky, Alan

    Kaminsky Harris Corporation RF Communications Division, USA ABSTRACT An innovative method for automatically in the desired pattern. The set of assigned channels is called a communication plan, or commplan. Designing. There is a set of available chan- nels the radios are allowed to use. Each channel is de- fined by its emission

  12. Summary Statistics of CPB-Qualified Public Radio Stations: Fiscal Year 1971.

    ERIC Educational Resources Information Center

    Lee, S. Young; Pedone, Ronald J.

    Basic statistics on finance, employment, and broadcast and production activities of 103 Corporation for Public Broadcasting (CPB)--qualified radio stations in the United States and Puerto Rico for Fiscal Year 1971 are collected. The first section of the report deals with total funds, income, direct operating costs, capital expenditures, and other…

  13. Summary Statistics of CPB-Qualified Public Radio Stations, Fiscal Year 1972.

    ERIC Educational Resources Information Center

    Lee, S. Young; Pedone, Ronald J.

    Statistics in the areas of finance, employment, and broadcast and production for CPB-qualified (Corporation for Public Broadcasting) public radio stations are given in this report. Tables in the area of finance are presented specifying total funds, income, direct operating costs, and capital expenditure. Employment is divided into all employment…

  14. Small Satellite Propulsion Options

    NASA Technical Reports Server (NTRS)

    Myers, Roger M.; Oleson, Steven R.; Curran, Francis M.; Schneider, Steven J.

    1994-01-01

    Advanced chemical and low power electric propulsion offer attractive options for small satellite propulsion. Applications include orbit raising, orbit maintenance, attitude control, repositioning, and deorbit of both Earth-space and planetary spacecraft. Potential propulsion technologies for these functions include high pressure Ir/Re bipropellant engines, very low power arcjets, Hall thrusters, and pulsed plasma thrusters, all of which have been shown to operate in manners consistent with currently planned small satellites. Mission analyses show that insertion of advanced propulsion technologies enables and/or greatly enhances many planned small satellite missions. Examples of commercial, DoD, and NASA missions are provided to illustrate the potential benefits of using advanced propulsion options on small satellites.

  15. Civil satellite navigation systems

    NASA Astrophysics Data System (ADS)

    Blanchard, Walter F.

    1991-07-01

    The use of satellite navigation for civil purposes is examined critically to compare the merits and costs of existing and practical satellite systems. Accuracy and range considerations are reviewed, and the basic requirements of radionavigation systems are set forth. Specific data are given regarding coverage area, integration with ground-based systems, monitoring and control, and accuracy. Systems reviewed include 'Starfix,' Inmarsat, EVA Vavsat, and Geostar/Locstar/Omnitracs, and extensive illustrations are provided to demonstrate constellation geometries. When in view, two or three geosynchronous satellites can provide acceptable fixing, and 9 satellites can provide global coverage. It is argued that systems such as 'Starfix' are commercially viable with less than 100 users, and Inmarsat is identified as an effective European civil system.

  16. Communication satellite antennas

    Microsoft Academic Search

    LEON J. RICARDI

    1977-01-01

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

  17. Disaster warning satellite study

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The Disaster Warning Satellite System is described. It will provide NOAA with an independent, mass communication system for the purpose of warning the public of impending disaster and issuing bulletins for corrective action to protect lives and property. The system consists of three major segments. The first segment is the network of state or regional offices that communicate with the central ground station; the second segment is the satellite that relays information from ground stations to home receivers; the third segment is composed of the home receivers that receive information from the satellite and provide an audio output to the public. The ground stations required in this system are linked together by two, separate, voice bandwidth communication channels on the Disaster Warning Satellites so that a communications link would be available in the event of disruption of land line service.

  18. Satellite Research Group

    NSDL National Science Digital Library

    NOAA's Ocean Remote Sensing Division runs the Satellite Research Group, which uses data from environmental satellites to study seasonal and interannual climate variability. Research areas include air-sea interaction (and transfers of heat, momentum, and water); the global hydrological cycle (including water vapor and precipitation); the Earth's radiation budget; and real-time monitoring of the El Nino/La Nina oscillation. Each research area is described in detail at the Website, and links connect users to the latest real-time geostationary satellite data images, as well as to the absolutely spectacular climate image archives. For researchers interested in regional or global scale climate patterns or the use of satellite technology for research purposes, this is an excellent resource.

  19. Corporate Governance and Corporate Social Responsibility in Bangladesh with special reference to Commercial Banks

    Microsoft Academic Search

    Victoria Wise; Muhammad Mahboob Ali

    2009-01-01

    This is an exploratory paper with the aim of determining the nature and extent of corporate social responsibility reporting in the banking sector in Bangladesh, and to assess the need to improve corporate social responsibility by such firms. Corporate social responsibility is associated with corporate governance and ethical business procedure. Good corporate governance is expected to underpin effective and efficient

  20. Ownership structure, corporate governance and corporate liquidity policy : Evidence from the Ghana Stock Exchange

    Microsoft Academic Search

    Godfred A. Bokpin; Zangina Isshaq; Francis Aboagye-Otchere

    2011-01-01

    Purpose – The purpose of this paper is to examine the impact of ownership structure and corporate governance on corporate liquidity policy from a developing country perspective, Ghana Stock Exchange (GSE). Design\\/methodology\\/approach – The authors adopt multiple regression analysis in estimating the relationship between ownership structure, corporate governance and corporate liquidity policy as well as the impact of corporate governance

  1. Radio efficiency of pulsars

    SciTech Connect

    Szary, Andrzej; Melikidze, George I.; Gil, Janusz [Kepler Institute of Astronomy, University of Zielona Góra, Lubuska 2, 65-265 Zielona Góra (Poland); Zhang, Bing [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States); Xu, Ren-Xin, E-mail: aszary@astro.ia.uz.zgora.pl, E-mail: zhang@physics.unlv.edu [School of Physics and Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

    2014-03-20

    We investigate radio emission efficiency, ?, of pulsars and report a near-linear inverse correlation between ? and the spin-down power, E-dot , as well as a near-linear correlation between ? and pulsar age, ?. This is a consequence of very weak, if any, dependences of radio luminosity, L, on pulsar period, P, and the period derivative, P-dot , in contrast to X-ray or ?-ray emission luminosities. The analysis of radio fluxes suggests that these correlations are not due to a selection effect, but are intrinsic to the pulsar radio emission physics. We have found that, although with a large variance, the radio luminosity of pulsars is ?10{sup 29} erg s{sup –1}, regardless of the position in the P-- P-dot diagram. Within such a picture, a model-independent statement can be made that the death line of radio pulsars corresponds to an upper limit in the efficiency of radio emission. If we introduce the maximum value for radio efficiency into the Monte Carlo-based population syntheses we can reproduce the observed sample using the random luminosity model. Using the Kolmogorov-Smirnov test on a synthetic flux distribution reveals a high probability of reproducing the observed distribution. Our results suggest that the plasma responsible for generating radio emission is produced under similar conditions regardless of pulsar age, dipolar magnetic field strength, and spin-down rate. The magnetic fields near the pulsar surface are likely dominated by crust-anchored, magnetic anomalies, which do not significantly differ among pulsars, leading to similar conditions for generating electron-positron pairs necessary to power radio emission.

  2. Satellite Delivery of Aviation Weather Data

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Haendel, Richard

    2001-01-01

    With aviation traffic continuing to increase worldwide, reducing the aviation accident rate and aviation schedule delays is of critical importance. In the United States, the National Aeronautics and Space Administration (NASA) has established the Aviation Safety Program and the Aviation System Capacity Program to develop and test new technologies to increase aviation safety and system capacity. Weather is a significant contributor to aviation accidents and schedule delays. The timely dissemination of weather information to decision makers in the aviation system, particularly to pilots, is essential in reducing system delays and weather related aviation accidents. The NASA Glenn Research Center is investigating improved methods of weather information dissemination through satellite broadcasting directly to aircraft. This paper describes an on-going cooperative research program with NASA, Rockwell Collins, WorldSpace, Jeppesen and American Airlines to evaluate the use of satellite digital audio radio service (SDARS) for low cost broadcast of aviation weather information, called Satellite Weather Information Service (SWIS). The description and results of the completed SWIS Phase 1 are presented, and the description of the on-going SWIS Phase 2 is given.

  3. Silicon Satellites: Picosats, Nanosats, and Microsats

    NASA Technical Reports Server (NTRS)

    Janson, Siegfried W.

    1995-01-01

    Silicon, the most abundant solid element in the Earth's lithosphere, is a useful material for spacecraft construction. Silicon is stronger than stainless steel, has a thermal conductivity about half that of aluminum, is transparent to much of the infrared radiation spectrum, and can form a stable oxide. These unique properties enable silicon to become most of the mass of a satellite, it can simultaneously function as structure, heat transfer system, radiation shield, optics, and semiconductor substrate. Semiconductor batch-fabrication techniques can produce low-power digital circuits, low-power analog circuits, silicon-based radio frequency circuits, and micro-electromechanical systems (MEMS) such as thrusters and acceleration sensors on silicon substrates. By exploiting these fabrication techniques, it is possible to produce highly-integrated satellites for a number of applications. This paper analyzes the limitations of silicon satellites due to size. Picosatellites (approximately 1 gram mass), nanosatellites (about 1 kg mass), and highly capable microsatellites (about 10 kg mass) can perform various missions with lifetimes of a few days to greater than a decade.

  4. Launching a Satellite

    NSDL National Science Digital Library

    The Concord Consortium

    2011-12-11

    Isaac Newton?s famous thought experiment about what would happen if you launched a cannon from a mountaintop at a high velocity comes to life with an interactive computer model. You are charged with the task of launching a satellite into space. Control the angle and speed at which the satellite is launched, and see the results to gain a basic understanding of escape velocity.

  5. Sea Turtle Satellite Tracking

    NSDL National Science Digital Library

    Near real-time tool for collecting, managing and sharing marine life satellite tracking data. Over 30 projects in US, Caribbean, Mediterranean, Indo-Pacific, and Australian waters. Provides links to background information for each project, the animals they are tracking, and maps that are updated regularly. Teaching resources include maps for tracking, suggestions for using data in lessons on geography, biology, earth science, math. Good introduction to satellite telemetry methodology and applications.

  6. G-MG Satellite

    NSDL National Science Digital Library

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: A satellite orbiting the earth uses radar to communicate with two control stations on the earth's surface. The satellite is in a geostationary orbit. T...

  7. Recent Korean R&D in Satellite Communications

    NASA Astrophysics Data System (ADS)

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

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

  8. Time varying interference statistical distribution for direct-to-user satellite applications

    Microsoft Academic Search

    Athanasios D. Panagopoulos

    2009-01-01

    Adjacent co-channel satellite systems might lead to unacceptable mutual radio interference levels due to their close spacing in orbit and to the reduced antenna sizes at the user's reception. Tropospheric propagation impairments along with the interference effects are of utmost importance for the reliable design of modern satellite communication systems operating at Ku (14\\/12 GHz) and Ka(30\\/20 GHz) frequency bands

  9. Harvard Corporation and Board of

    E-print Network

    President Harvard Corporation and Board of Overseers VP & Secretary Treasurer Harvard Mgmt Co Policy VP General Counsel VP Alumni Affairs & Development VP Harvard Public Affairs & Communications VP collaboration in the sciences, social sciences, and humanities; ·Improving Harvard's performance in building

  10. Corporate Partners with industry to

    E-print Network

    that is investigating active diesel particulate filters." - Ken Boshart, President, Boshart Engineering Bank of America Public Affairs, Bank of America innovation Economy Corporation (gold Member) "The economy needs, our public-private pa

  11. The Corporate Propensity to Save

    Microsoft Academic Search

    LEIGH A. RIDDICK; TONI M. WHITED

    2009-01-01

    Why do corporations accumulate liquid assets? We show theoretically that intertemporal trade-offs between interest income taxation and the cost of external finance determine optimal savings. Intriguingly, we find that, controlling for Tobin's?\\

  12. Corporal punishment in Tanzania's schools

    NASA Astrophysics Data System (ADS)

    Feinstein, Sheryl; Mwahombela, Lucas

    2010-10-01

    The purpose of this survey was to acquire descriptive information regarding corporal punishment in Tanzania's O-level secondary schools. 448 individuals participated in the study: 254 teachers and 194 students, all from government or private secondary schools in the Iringa Region of Tanzania. In addition, 14 students and 14 teachers were interviewed. It was found that corporal punishment was the most common form of punishment in secondary schools. The majority of teachers supported its continued use, but believed in moderation. The majority of students and teachers were unaware of national laws to restrict corporal punishment. There was agreement between students and teachers that corporal punishment was used for major and minor student offences such as misbehaviour and tardiness. Students reported disliking the practice and believed it was ineffective and resulted in emotional, as well as physical, distress.

  13. Corporate Security and Conflict Outcomes 

    E-print Network

    Tkach, Benjamin K

    2013-10-21

    This dissertation investigates the effects of private security firms (PSFs) on conflict outcomes. PSFs are corporations that are publicly or individually owned that provide security services for hire. Security services ...

  14. ASAP- ARTIFICIAL SATELLITE ANALYSIS PROGRAM

    NASA Technical Reports Server (NTRS)

    Kwok, J.

    1994-01-01

    The Artificial Satellite Analysis Program (ASAP) is a general orbit prediction program which incorporates sufficient orbit modeling accuracy for mission design, maneuver analysis, and mission planning. ASAP is suitable for studying planetary orbit missions with spacecraft trajectories of reconnaissance (flyby) and exploratory (mapping) nature. Sample data is included for a geosynchronous station drift cycle study, a Venus radar mapping strategy, a frozen orbit about Mars, and a repeat ground trace orbit. ASAP uses Cowell's method in the numerical integration of the equations of motion. The orbital mechanics calculation contains perturbations due to non-sphericity (up to a 40 X 40 field) of the planet, lunar and solar effects, and drag and solar radiation pressure. An 8th order Runge-Kutta integration scheme with variable step size control is used for efficient propagation. The input includes the classical osculating elements, orbital elements of the sun relative to the planet, reference time and dates, drag coefficient, gravitational constants, and planet radius, rotation rate, etc. The printed output contains Cartesian coordinates, velocity, equinoctial elements, and classical elements for each time step or event step. At each step, selected output is added to a plot file. The ASAP package includes a program for sorting this plot file. LOTUS 1-2-3 is used in the supplied examples to graph the results, but any graphics software package could be used to process the plot file. ASAP is not written to be mission-specific. Instead, it is intended to be used for most planetary orbiting missions. As a consequence, the user has to have some basic understanding of orbital mechanics to provide the correct input and interpret the subsequent output. ASAP is written in FORTRAN 77 for batch execution and has been implemented on an IBM PC compatible computer operating under MS-DOS. The ASAP package requires a math coprocessor and a minimum of 256K RAM. This program was last updated in 1988 with version 2.03. IBM PC is a registered trademark of International Business Machines. MS-DOS is a registered trademark of Microsoft Corporation. Lotus and 1-2-3 are registered trademarks of Lotus Development Corporation.

  15. Corporate Governance and Accounting Scandals

    Microsoft Academic Search

    Anup Agrawal; Sahiba Chadha

    2005-01-01

    This paper empirically examines whether certain corporate governance mechanisms are related to the probability of a company restating its earnings. We examine a sample of 159 U.S. public companies that restated earnings and an industry-size matched sample of control firms. We have assembled a novel, hand-collected data set that measures the corporate governance characteristics of these 318 firms. We find

  16. Corporal punishment and child adjustment

    Microsoft Academic Search

    Katherine J. Aucoin; Paul J. Frick; S. Doug Bodin

    2006-01-01

    The association between corporal punishment and children's emotional and behavioral functioning was studied in a sample of 98 non-referred children with a mean age of 12.35 (SD=1.72) recruited from two school systems in the southeastern United States. Children were divided into those who had experienced no corporal punishment over approximately a two-week period, those who had experienced mild levels of

  17. Extragalactic Radio Jets and Intergalactic Medium 2

    NASA Technical Reports Server (NTRS)

    Birkinshaw, Mark

    2000-01-01

    During the mid 1990s, the ROSAT satellite provided the highest resolution X-ray imaging, with useful X-ray spectroscopy, and excellent sensitivity. ROSAT"s PSPC and HRI instruments gave us our first high-quality data on the AGN phenomenon in nearby galaxies - the central theme of this research project. Initially this project concentrated on separating the AGN-related component of the X-ray emission from thermal radiation from the surrounding atmospheres in radio galaxies. There was ample reason to believe that this separation would be possible, although earlier work had taken the view that the X-ray emission from radio galaxies is either wholly AGN-related (and hence of sub-arcsec scale), or wholly from the galaxy and cluster atmospheres (and hence of scales - 10 arcsec or more in the low-redshift radio galaxies that we chose to study). First with the PSPC, and then with the HRI, we proved that a wide range of AGN core X ray emissivities could be found, and that the generic radio galaxy produces both AGN-related and atmosphere-related X-radiation. We demonstrated that there is a close relationship between the core X-ray power and the core radio power, and found instances in which the hot atmospheres of the galaxies must be participating in cooling flows, and other cases where those atmospheres are relatively stable. In some cases, there is a clear active relationship between the extended radio emission and the X-ray atmospheres: thus in NGC 326, we interpret the distorted radio structure as evidence of buoyancy as the radio plasma rises through the cluster atmosphere. In 3C 449, we can see that the radio plasma is displacing the X-ray emitting gas. In a further case (NGC 1265), we hoped that the motion of a radio galaxy through a cluster atmosphere would be apparent though the wake that it might establish - unfortunately, other structure in the atmosphere of the Perseus cluster tends to dominate our X-ray image, and no useful limits could be placed on the strength of the wake. In the light of so-called "unified" models of AGN, it is expected that the low-power radio galaxies studied under these programmes are the unbeamed counterparts of BL Lac objects. Accordingly, we predicted that BL Lac objects, as a class, should show X-ray halos from atmospheres similar to those associated with radio galaxies. The difficulty with studying this is that BL Lac objects tend to be X-ray bright, and the halos then vanish under the wings of the point response function. We found a BL Lac with less of a dynamic range problem, mapped it with the ROSAT HRI, and duly found an atmosphere (Hardcastle et al. 1999). Unfortunately for unification models, this atmosphere is exceptionally dense, so that it must be participating in an intense cooling flow. The implications of this for unification models are far from clear, and further work is under way.

  18. Ionosphere/microwave beam interaction study. [satellite solar energy conversion

    NASA Technical Reports Server (NTRS)

    Duncan, L. M.; Gordon, W. E.

    1977-01-01

    A solar power satellite microwave power density of 20mw sq cm was confirmed as the level where nonlinear interactions may occur in the ionosphere, particularly at 100 km altitude. Radio wave heating at this altitude, produced at the Arecibo Observatory, yielded negative results for radio wave heating of an underdense ionosphere. Overdense heating produced striations in the ionosphere which may cause severe radio frequency interference problems under certain conditions. The effects of thermal self-focusing are shown to be limited severely geographically. The aspect sensitivity of field-aligned striations makes interference-free regions above magnetic latitude about 60 deg. A test program is proposed to simulate the interaction of the SPS beam with the ionosphere, to measure the effects of the interaction on the ionosphere and on communication and navigation systems, and to interpret the results.

  19. Multiple Radios for Effective Rendezvous in Cognitive Radio Networks

    E-print Network

    Chu, Xiaowen

    Multiple Radios for Effective Rendezvous in Cognitive Radio Networks Lu Yu1 , Hai Liu1 , Yiu in cognitive radio networks (CRNs) for establishing a communication link on a commonly-available channel, we investigate the rendezvous problem in CRNs where cognitive users are equipped with multiple radios

  20. Multiple Radios for Fast Rendezvous in Cognitive Radio Networks

    E-print Network

    Chu, Xiaowen

    , Xiaowen Chu, and Zhiyong Lin Abstract--Rendezvous is a fundamental operation in cognitive radio networks1 Multiple Radios for Fast Rendezvous in Cognitive Radio Networks Lu Yu, Hai Liu, Yiu-Wing Leung. The existing work on rendezvous implicitly assumes that each cognitive user is equipped with one radio (i

  1. Radio-communications architectures 1 Radio-communications architectures

    E-print Network

    Paris-Sud XI, Université de

    Radio-communications architectures 1 X Radio-communications architectures Antoine Diet*, Martine Paris-Est, ESYCOM, ESIEE Paris France 1. Introduction Wireless communications, i.e. radio-communications of the architecture is that a transceiver is built with respect to the radio-communications signals. We classify them

  2. Corporeal reflexivity and autism.

    PubMed

    Ochs, Elinor

    2015-06-01

    Ethnographic video recordings of high functioning children with autism or Aspergers Syndrome in everyday social encounters evidence their first person perspectives. High quality visual and audio data allow detailed analysis of children's bodies and talk as loci of reflexivity. Corporeal reflexivity involves displays of awareness of one's body as an experiencing subject and a physical object accessible to the gaze of others. Gaze, demeanor, actions, and sotto voce commentaries on unfolding situations indicate a range of moment-by-moment reflexive responses to social situations. Autism is associated with neurologically based motor problems (e.g. delayed action-goal coordination, clumsiness) and highly repetitive movements to self-soothe. These behaviors can provoke derision among classmates at school. Focusing on a 9-year-old girl's encounters with peers on the playground, this study documents precisely how autistic children can become enmeshed as unwitting objects of stigma and how they reflect upon their social rejection as it transpires. Children with autism spectrum disorders in laboratory settings manifest diminished understandings of social emotions such as embarrassment, as part of a more general impairment in social perspective-taking. Video ethnography, however, takes us further, into discovering autistic children's subjective sense of vulnerability to the gaze of classmates. PMID:25939529

  3. Unbundling the corporation.

    PubMed

    Hagel, J; Singer, M

    1999-01-01

    No matter how monolithic they may seem, most companies are really engaged in three kinds of businesses. One business attracts customers. Another develops products. The third oversees operations. Although organizationally intertwined, these businesses have conflicting characteristics. It takes a big investment to find and develop a relationship with a customer, so profitability hinges on achieving economies of scope. But speed, not scope, drives the economics of product innovation. And the high fixed costs of capital-intensive infrastructure businesses require economies of scale. Scope, speed, and scale can't be optimized simultaneously, so trade-offs have to be made when the three businesses are bundled into one corporation. Historically, they have been bundled because the interaction costs--the friction--incurred by separating them were too high. But we are on the verge of a worldwide reduction in interaction costs, the authors contend, as electronic networks drive down the costs of communicating and of exchanging data. Activities that companies have always believed were central to their businesses will suddenly be offered by new, specialized competitors that won't have to make trade-offs. Ultimately, the authors predict, traditional businesses will unbundle and then rebundle into large infrastructure and customer-relationship businesses and small, nimble product innovation companies. And executives in many industries will be forced to ask the most basic question about their companies: What business are we really in? Their answer will determine their fate in an increasingly frictionless economy. PMID:10387769

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

    NASA Astrophysics Data System (ADS)

    Yasui, Yoshitsugu

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

  5. OneWorldRadio

    NSDL National Science Digital Library

    A number of media commentators have been complaining lately about the lack of ideological viewpoints within the vast sea of radio programming, something that has not been lost on the people at OneWorldRadio. Funded by the Department for International Development, OneWorld Radio is part of an international network of over 1200 partner organizations that are utilizing the internet "to promote human rights and sustainable development worldwide." With online audio content from member organizations (such as radio stations) available in French, Spanish, and a number of other languages, visitors can listen or download any one of hundreds of programs archived here. Additionally, visitors can elect to search their impressive archive by language, region, or topic. Persons interested in the use of radio for development and human rights will want to examine the news and events section as it contains important updates about events dealing with conferences on media freedom throughout the world and links to important radio broadcasts of note. Finally, visitors (and all who sign up for the free membership) can elect to receive the helpful OneWorldRadio e-newsletter.

  6. Radio source evolution

    E-print Network

    Perucho, Manel

    2015-01-01

    Baldwin (1982) wrote that "the distribution of sources in the radio luminosity, P, overall physical size, D, diagram" could be considered as "the radio astronomer's H-R diagram". However, unlike the case of stars, not only the intrinsic properties of the jets, but also those of the host galaxy and the intergalactic medium are relevant to explain the evolutionary tracks of radio radio sources. In this contribution I review the current status of our understanding of the evolution of radio sources from a theoretical and numerical perspective, using the P-D diagram as a framework. An excess of compact (linear size < 10 kpc) sources could be explained by low-power jets being decelerated within the host galaxy, as shown by recent numerical simulations. These decelerated jets could also explain the population of the radio sources that have been recently classified as FR0. I will discuss the possible tracks that radio sources may follow within this diagram, and some of the physical processes that can explain the d...

  7. Generic satellite monitoring expert system

    NASA Astrophysics Data System (ADS)

    Kelemen, Loretta A.

    1994-12-01

    Air Force Satellite Operations is undergoing major changes. Operators no longer receive detailed satellite training, instead they are taught basic fundamentals of satellite operations and expected to control multiple multimillion dollar satellites. The need is clear. An efficient and economical automated system is necessary to assist the satellite operator in the daily tasks of maintaining these DOD priority resources. Satellite intelligent controllers have been under R&D since the early 1980's to meet this need. These systems, however, have focused on the control of one constellation of satellites. In a military striving for efficiency and lower costs, developing a unique intelligent controller for each satellite constellation is unaffordable. This research provided support for the concept of a generic satellite intelligent controller, through the development of a prototype expert system. This capability would allow a generic rule-base to operate and maintain multiple satellite systems. The initial prototype detected anomalies on one subsystem of two different satellites. After the third satellite prototype was created, a third satellite was analyzed to show support for the viability of the satellite prototype. More research is necessary, but this thesis has created support for the concept of generic satellite controller and has laid the foundation for future extensions.

  8. --ibm corporate responsibility report--The IBM Corporate Responsibility Report represents the information reported in various categories on IBM's Corporate Responsibility Web site.

    E-print Network

    Accountability and Sustainability · Corporate Citizenship · Global Leadership Network · GRI Index Supply Chain-- ibm corporate responsibility report-- #12;The IBM Corporate Responsibility Report represents the information reported in various categories on IBM's Corporate Responsibility Web site. Every effort has been

  9. 12 CFR 704.11 - Corporate Credit Union Service Organizations (Corporate CUSOs).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 false Corporate Credit Union Service Organizations (Corporate CUSOs...11 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS CORPORATE CREDIT UNIONS § 704.11...

  10. 12 CFR 704.11 - Corporate Credit Union Service Organizations (Corporate CUSOs).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 false Corporate Credit Union Service Organizations (Corporate CUSOs...11 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS CORPORATE CREDIT UNIONS § 704.11...

  11. 12 CFR 704.11 - Corporate Credit Union Service Organizations (Corporate CUSOs).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 false Corporate Credit Union Service Organizations (Corporate CUSOs...11 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS CORPORATE CREDIT UNIONS § 704.11...

  12. 78 FR 60375 - Rogue Valley Terminal Railroad Corporation-Corporate Family Transaction Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-01

    ...Docket No. FD 35768] Rogue Valley Terminal Railroad Corporation--Corporate...Transaction Exemption Rogue Valley Terminal Railroad Corporation (Rogue Valley...WCTU Railway LLC, or White City Terminal & Utility Co. (WCTU) and...

  13. 75 FR 20389 - Resinoid Engineering Corporation Hebron, OH; Resinoid Engineering Corporation Heath, OH; Amended...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-19

    ...TA-W-71,175; TA-W-71,175A] Resinoid Engineering Corporation Hebron, OH; Resinoid Engineering Corporation Heath, OH; Amended Certification...2010, applicable to workers of Resinoid Engineering Corporation, Hebron, Ohio. The...

  14. 76 FR 35024 - Precision Dynamics Corporation San Fernando, CA; Precision Dynamics Corporation, Also Known as...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-15

    ...Dynamics Corporation, Also Known as the St. John Companies, Valencia, CA; Amended Certification...Dynamics Corporation, also known as The St. John Companies, operated in conjunction with...Dynamics Corporation, also known as The St. John Companies, Valencia, California...

  15. Density waves in Saturn's rings probed by radio and optical occultation - Observational tests of theory

    NASA Technical Reports Server (NTRS)

    Brophy, Thomas G.; Rosen, Paul A.

    1992-01-01

    A parallel examination is conducted of Voyager radio and photopolarimeter occultation observations of the Saturn A ring's density waves. The radio instrument waves exhibit an average -90 deg offset from the dynamical phase. A warping height of about 100-m amplitude can qualtitatively reproduce this phase shift, while preserving the overall model wave shape. These results may be profoundly relevant for satellite-ring torque calculations in Saturn's rings, given the deposition of all of the net torque of the standard model in the first wavelength.

  16. An experiment to enable commercial mobile satellite service

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  17. Observations of OH in comet Levy with the Nancay radio telescope

    NASA Technical Reports Server (NTRS)

    Bockelee-Morvan, Dominique; Colom, P.; Crovisier, Jacques; Gerard, E.; Bourgois, G.

    1992-01-01

    Due to extremely favorable excitation conditions, comet Levy (1990c) exhibited in August-September 1990 the strongest OH 18-cm signal ever recorded in a comet at the Nancay radio telescope. This unique opportunity was used to measure the OH satellite lines at 1612 and 1721 MHz, to perform extensive mapping of the OH radio emission and to make a sensitive evaluation of the cometary magnetic field, of the H2O outflow velocity and of the OH production rate.

  18. A new design for a very low frequency spaceborne radio interferometer

    Microsoft Academic Search

    Divya Oberoi; Jean-Louis Pinçon

    2005-01-01

    The nontransparency and severe propagation effects of the terrestrial ionosphere make it impossible for Earth-based instruments to study the universe at low radio frequencies. An exploration of the low-frequency radio window with the resolution and sensitivity essential to meet the scientific objectives will necessarily require a dedicated satellite-based interferometer operating at these frequencies. Such missions have been proposed in the

  19. GPS Radio Occultation with CHAMP and GRACE: Recent Results

    Microsoft Academic Search

    J. Wickert; T. Schmidt; G. Beyerle; G. Michalak; R. König; S. Heise; C. Reigber

    The German CHAMP (CHAllenging Minisatellite Payload) satellite provides continuously GPS radio occultation data since February\\u000a 2001. The measurements are analyzed by an operational orbit and occultation processing system at GFZ. In total ?170 000 high\\u000a quality globally distributed vertical profiles of refractivity, temperature and water vapor are provided as of October 2004.\\u000a The ground infrastructure from GFZ allows for the

  20. A Tour of the Goldstone-Apple Valley Radio Telescope

    NASA Technical Reports Server (NTRS)

    Ardenski, Brooke; Stephan, George R.

    1997-01-01

    Goldstone-Apple Valley Radio Telescope (GAVRT) is located in a remote area of the Mojave Desert, 40 miles north of Barstow, California. The antenna, identified as DSS-12, is a 34-meter diameter dish, 11 times the diameter of a ten foot microwave dish used for satellite television. DSS-12 has been used by NASA to communicate with robotic space probes for more than thirty years.

  1. An Introduction to Radio Astronomy

    Microsoft Academic Search

    Bernard F. Burke; Francis Graham-Smith

    1996-01-01

    Radio astronomy uses unique observational techniques and offers the only way to investigate many phenomena in the Universe. This book, by two founders of the field, presents both a clear introduction to radio telescopes and techniques and a broad overview of the radio universe. In the first half of the book, we are shown clearly how radio telescopes work -

  2. Packet Radio for Library Automation.

    ERIC Educational Resources Information Center

    Brownrigg, Edwin B.; And Others

    1984-01-01

    This tutorial on packet radio (communication system using radio and digital packet-switching technology) highlights radio transmission of data, brief history, special considerations in applying packet radio to library online catalogs, technology, defining protocol at physical and network levels, security, geographic coverage, and components. (A…

  3. Aspects of the future use of broadcasting and remote sensing satellites

    NASA Astrophysics Data System (ADS)

    Hartl, P.

    1981-05-01

    The increasing use of broadcasting satellites is first discussed and exemplified on a general growth curve. Particular attention is then given to current TV and radio satellites and commercial satellites as well as future large satellites. The market situation and aspects for future technical development are also considered. With respect to remote sensing, preoperational satellites are expected to be in use until the late 1980s; the operational phase for these satellites is expected sometime in the 1990s. The possibility of developing a microwave remote sensing satellite for sea-state and weather forecasting is discussed: the satellite should have the ability to communicate directly with ships as well as provide the facilities needed for search and rescue purposes. A list of the current broadcasting and remote sensing satellites is given. Reflectors and feed systems of the Intelsat IV A are shown. The surface converage of the Intelsat V is illustrated on a map, and a diagram of the European Satellite Assembly System is presented.

  4. Earth-satellite propagation above GHz: Papers from the 1972 spring URSI session on experiments utilizing the ATS-5 satellite

    NASA Technical Reports Server (NTRS)

    Ippolito, L. J. (compiler)

    1972-01-01

    Papers are reported from the Special Session on Earth-Satellite Propagation Above 10 GHz, presented at The 1972 Spring Meeting of the United States National Committee, International Union of Radio Science, April 1972, Washington, D. C. This session was devoted to propagation measurements associated with the Applications Technology Satellite (ATS-5), which provided the first operational earth-space links at frequencies above 15 GHz. A comprehensive summary is presented of the major results of the ATS-5 experiment measurements and related radiometric, radar and meteorological studies. The papers are organized around seven selected areas of interest, with the results of the various investigators combined into a single paper presented by a principal author for that area. A comprehensive report is provided on the results of the ATS-5 satellite to earth transmissions. A complete list of published reports and presentations related to the ATS-5 Millimeter Wave Experiment is included.

  5. Superfine Structure of Jovian Millisecond Radio Bursts

    NASA Astrophysics Data System (ADS)

    Rucker, H. O.; Litvinenko, G.; Taubenschuss, U.; Leitner, M.; Lecacheux, A.; Konovalenko, A.

    2004-05-01

    Jupiter decameter (DAM) radio emission mainly consists of wide-band radio storms with time scales in seconds (L-bursts) and milliseconds (S-bursts), the latter comprising a series of short pulses with duration of a few to tens of milliseconds, and strongly controlled by the satellite Io. First in-depth analysis of the subpulse structure was made by Carr and Reyes (1999) with the discovery of successive deep envelope modulations, with time resolution better than 30 microseconds, and during these subpulse periods the discovery of phase coherence. Recent observations by means of the newly developed waveform receiver (at present unsurpassed in spectral resolution) and connected to the decameter world-largest radio telescope UTR-2 (Kharkov) yielded waveform measurements of Jovian S-bursts which have been analyzed by the wavelet analysis method. Main outcome of the present investigation is the detection of clear signatures of microsecond modulations, providing evidence of a superfine burst structure with the following parameters: a) instantaneous frequency band of one separated microsecond pulse of 100 to 300 kHz, b) time duration of one separated micropulse of 6 to 15 microseconds, and c) time interval between closest subsequent microsecond pulses of 5 to 25 microseconds. The apparent frequency drift of a millisecond burst evidently results from sequentially decreasing frequencies of subsequent subpulses, each representing an island of phase coherent gyrating electron bunches.

  6. The Globalstar mobile satellite system for worldwide personal communications

    NASA Astrophysics Data System (ADS)

    Wiedeman, Robert A.; Viterbi, Andrew J.

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

  7. Modeling Radio Networks

    E-print Network

    Lynch, Nancy

    2009-06-04

    We describe a modeling framework and collection of foundational composition results for the study of probabilistic distributed algorithms in synchronous radio networks. Existing results in this setting rely on informal ...

  8. Eratosthenes via Ham Radio

    ERIC Educational Resources Information Center

    Koser, John F.

    1975-01-01

    A secondary geology class used Eratosthenes' method for measuring the circumference of the earth by comparing their measurements of the shadow of a vertical rod to the measurements made by another person contacted by ham radio. (MLH)

  9. A Radio Theatre Laboratory.

    ERIC Educational Resources Information Center

    Potter, Doug

    1982-01-01

    Briefly discusses the potential of radio theater for high school drama. Sketches a modest equipment layout that will provide students with the fundamental combination of hardware and wires to produce audio drama. (PD)

  10. RADIO-SCIENTIFIQUE INTERNATIONALE

    E-print Network

    Goldberg, Bennett

    the Earths ionospherebeginningwiththelaunch of Sputnik, died peacefully in his sleep at his home in Newton at middle and auroral latitudes, first using radio starsandthensatellitebeacons,to define an equatorward

  11. British Broadcasting Corporation (BBC): Science and Nature (title provided or enhanced by cataloger)

    NSDL National Science Digital Library

    This is the Science and Nature portal for the British Broadcasting Corporation (BBC). Topics include Animals, Prehistoric Life, Human Body and Mind, Genes, Space, and Hot Topics in science and nature. Other links lead to featured stories, message boards, quizzes, picture galleries, games, wallpaper, screensavers, and web postcards. In addition, there is a list of science programs on radio and television and links to science news stories.

  12. PUBLIC INTEREST ISSUES, AND SUPPLEMENTAL LEGAL BRIEF, BEFORE THE FEDERAL COMMUNICATIONS COMMISSION, IN THE MATTER OF THE ESTABLISHMENT OF DOMESTIC COMMUNICATIONS SATELLITE FACILITIES BY NON-GOVERNMENTAL ENTITIES, DOCKET 16495.

    ERIC Educational Resources Information Center

    Ford Foundation, New York, NY.

    VOLUME I OF THE FORD FOUNDATION RESPONSE TO THE ORIGINAL AND SUPPLEMENTAL FEDERAL COMMUNICATIONS COMMISSION (FCC) NOTES OF INQUIRY CONTAINS SUGGESTIONS FOR COOPERATION BETWEEN THE PROPOSED SYSTEMS OF THE CORPORATION FOR PUBLIC TELEVISION (CPTV) AND THE BROADCASTERS' NONPROFIT SATELLITE CORPORATION (BNSC) ON STRUCTURE, FISCAL POLICY, AND…

  13. Astrometry of southern radio sources

    NASA Technical Reports Server (NTRS)

    White, Graeme L.; Jauncey, David L.; Harvey, Bruce R.; Savage, Ann; Gulkis, Samuel; Preston, Robert A.

    1991-01-01

    An overview is presented of a number of astrometry and astrophysics programs based on radio sources from the Parkes 2.7 GHz catalogs. The programs cover the optical identification and spectroscopy of flat-spectrum Parkes sources and the determination of their milliarcsecond radio structures and positions. Work is also in progress to tie together the radio and Hipparcos positional reference frames. A parallel program of radio and optical astrometry of southern radio stars is also under way.

  14. Radio Emission from Supernovae

    Microsoft Academic Search

    J. I. Katz

    2001-01-01

    I consider radio emission from the remarkable supernova (SN) 1998bw. Decay of 56Ni and 56Co produces a gamma-ray flux, whose Compton-scattered electrons naturally explain the observed mildly relativistic expansion of the radio source and its double-peaked history. Such models require a surrounding plasma, perhaps produced by the supernova progenitor, whose interaction with the nonrelativistic debris may account for the observed

  15. Integration between terrestrial-based and satellite-based land mobile communications systems

    NASA Technical Reports Server (NTRS)

    Arcidiancono, Antonio

    1990-01-01

    A survey is given of several approaches to improving the performance and marketability of mobile satellite systems (MSS). The provision of voice/data services in the future regional European Land Mobile Satellite System (LMSS), network integration between the Digital Cellular Mobile System (GSM) and LMSS, the identification of critical areas for the implementation of integrated GSM/LMSS areas, space segment scenarios, LMSS for digital trunked private mobile radio (PMR) services, and code division multiple access (CDMA) techniques for a terrestrial/satellite system are covered.

  16. Uranus satellites - Surface properties

    NASA Technical Reports Server (NTRS)

    Veverka, J.; Brown, R. H.; Bell, Jeffrey F.

    1991-01-01

    The post-Voyager knowledge of the photometric, colorimetric, spectral, and thermal properties of the Uranian satellites is reviewed, focusing on such fundamental physical properties as albedo, color, and surface texture. While albedo variations of at least a factor of 2 exist, color differences are almost absent (Miranda) or subdued (Oberon). In the case of Titania, the strong opposition effect reported by ground-based observers was confirmed by Voyager. Voyager did not observe the opposition parts of the phase curves of the other satellites. Voyager thermal observations of Ariel and Miranda suggest that both have highly porous regoliths, thermophysically similar to those of Jupiter's icy satellites. At the time of the flyby (south pole facing the sun), maximum surface temperatures reached or exceeded 85 K, but nighttime polar temperatures are predicted to drop to 20 to 30 K because each pole spends about 40 yr in darkness. Ground-based spectroscopy identified water ice as an important surface constituent.

  17. The Clementine satellite

    SciTech Connect

    Not Available

    1994-06-01

    The first US satellite to the Moon in more than two decades was launched from Vandenberg Air Force Base (Santa Barbara County), California, on January 25, 1994. The satellite was named Clementine because it carried only enough fuel to complete its mission before it was [open quotes]lost and gone forever.[close quotes] The Clementine satellite tested 23 advanced technologies during its mission for the Ballistic Missile Defense Organization. In fulfilling its scientific goals, Clementine provided a wealth of information relevant to the mineralogy of the lunar surface. Using six on-board cameras designed and built at the Laboratory, Clementine mapped the entire surface of the Moon at resolutions never before attained. Clementine also provided range data that will be used to construct a relief map of the lunar surface.

  18. Soviet early warning satellites

    NASA Astrophysics Data System (ADS)

    Perry, G. E.

    1982-02-01

    Satellite orbits and groups for the Cosmos spacecraft are discussed, noting that the orbits are configured to provide full early warning system coverage. The regular crossing of a ground track which includes all the Minuteman bases in the U.S. is noted, as are time constraints for the launch into a suitable orbit without introducing orbital anomalies. Cosmos 1024 was observed to need four corrections in order to reach a point where free libration over a fixed ground station was possible for a year until replacement by the Cosmos 1124 occurred. The current configuration is a total of nine satellites with 40 deg spacing, which yields full coverage, although it is indicated that only three satellites ever operate simultaneously.

  19. Flux density monitoring of radio stars observable by HIPPARCOS at S-band and X-band

    NASA Astrophysics Data System (ADS)

    Estalella, R.; Paredes, J. M.; Rius, A.

    1983-08-01

    Single-dish simultaneous S-band (13 cm) and X-band (3.6 cm) flux density measuremets of radio stars are reported. The aim of the observational program is to monitor the variability and flux density of radio stars with an optical counterpart observable by the future astrometric satellite Hipparcos. From a list of 69 selected radio stars for astrometric purposes, 49 of them have been observed during 1982 with the 64 m antenna of the Madrid DSCC. The number of radio stars that have been detected is 15.

  20. Radio maps around five spiral and peculiar galaxies.

    NASA Technical Reports Server (NTRS)

    Arp, H.

    1973-01-01

    Areas of from 1 to 2 degrees square around five spiral and peculiar galaxies of apparent brightness between 10.3 and 12.7 mag have been mapped at a wavelength of 13 cm. In this small sample of observations it is found that, on the average, about two, counting the galaxy itself, radio sources of flux strength between 0.1 and 0.4 f.u. are physically associated with each spiral. This result supports the conclusion of De Jong that satellite radio sources are associated with spiral galaxies. If these preliminary results are indicative, then the radio sources associated with spiral galaxies differ from those classically associated with elliptical galaxies by being (1) intrinsically weaker and (2) not as accurately aligned as pairs across the central galaxy.