Note: This page contains sample records for the topic radio satellite corporation from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

The Agricultural Satellite Corporation  

Microsoft Academic Search

The Agricultural satellite Corporation (AG*SAT) is a consortium of 43 land-grant universities and two agencies of the USDA joined together to produce and share educational programming via satellite, computer, and other technologies. Sparked by the opportunity to receive Federal funding for satellite receive and transmit facilities, the institutions have invested financial and personnal resources in the purchase and installation of

Randall G. Bretz

1993-01-01

2

Radio determination satellite service  

NASA Astrophysics Data System (ADS)

The capabilities and measured performance of a geosynchronous satellite-based service called the radio determination satellite service (RDSS), which operates at radio frequencies allocated by the International Telecommunications Union (ITU) and is licensed in the United States by the Federal Communications Commission (FCC), are discussed. Plans for both improvement in capability and expansion to nearly global coverage are described. Since RDSS can also provide radio navigation, some comparisons of this service with the Global Positioning System (GPS) are made.

Briskman, Robert D.

1990-07-01

3

Satellite communications and amateur radio  

Microsoft Academic Search

Amateur radio use of Radio-1 and Radio-2 satellite communications is described since its beginning in October, 1978, which involves cooperation between DOSAAF and engineering and student design bodies. Second generation satellites Radio-3 and Radio-8 offered the possibility of an expanded system, and much work was done to increase useful life and reliability of space radio communications. Soviet and foreign radio

A. Abolits

1985-01-01

4

Radio broadcasting via satellite  

NASA Astrophysics Data System (ADS)

Market areas offering potential for future narrowband broadcast satellites are examined, including international public diplomacy, government- and advertising-supported, and business-application usages. Technical issues such as frequency allocation, spacecraft types, transmission parameters, and radio receiver characteristics are outlined. Service and system requirements, advertising revenue, and business communications services are among the economic issues discussed. The institutional framework required to provide an operational radio broadcast service is studied, and new initiatives in direct broadcast audio radio systems, encompassing studies, tests, in-orbit demonstrations of, and proposals for national and international commercial broadcast services are considered.

Helm, Neil R.; Pritchard, Wilbur L.

1990-10-01

5

Satellite Imaging Corporation: IKONOS Satellite Images  

NSDL National Science Digital Library

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.

Corporation, Satellite I.

6

Satellite Imaging Corporation  

NSDL National Science Digital Library

Satellite imagery and aerial photography incorporated with geographic information systems GIS can give coastal resource managers and emergency officials a wealth of information for assessment analysis and monitoring of natural disasters such as hurricane,s tornadoes and cyclone damage from small to large regions around the globe.

Romeijn, Monique; Corporation, Satellite I.

7

Direct Broadcast Satellite: Radio Program  

NASA Astrophysics Data System (ADS)

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.

Hollansworth, James E.

1992-10-01

8

OSCAR - Amateur radio satellites and spacecraft  

Microsoft Academic Search

An historical account is presented of the Orbital Satellite Carrying Amateur Radio (OSCAR) RS series, which was primarily intended for relaying amateur radio signals, along with a description of the latest satellite in the OSCAR series, UOSAT, which differs from its predecessors in its capabilities for conducting experiments on ionospheric research. UOSAT's experimental facilities include a set of radio beacons,

A. C. Gee

1982-01-01

9

Sirius Satellite Radio: Radio entertainment in the sky  

Microsoft Academic Search

Satellite broadcasting of radio programs is an effective means of serving large and distributed markets. A space-based radio system can provide about 100 high quality music, voice, and data channels to users spread over a vast geographic area. Employing digital technology and an elaborate system design, this approach significantly outperforms traditional AM and FM radio broadcasting in signal quality, program

F. Davarian

2002-01-01

10

Satellite Television Corporations's DBS system - An update  

NASA Astrophysics Data System (ADS)

In late 1980, a request was made for approval of a direct broadcast satellite (DBS) system. The considered DBS system is to provide nationwide pay-television service on a subscription basis. The system proposed in the application to the Federal Communications Commission would provide three channels of television, using four three-channel satellites. Attention is given to the system configuration, system tradeoffs, a plan of the 1983 Regional Administrative Radio Conference, orbit locations and channel frequencies, satellite status, home equipment status, advanced concepts, and the status of the Las Vegas Broadcast Complex. AIAA Paper 84-0664

Martin, E. R.

11

Australian Broadcasting Corporation Online: Radio National  

NSDL National Science Digital Library

The highlights of this Australian Broadcasting Corporation site are transcripts of radio shows in the areas of health, law, religion, sports, and current affairs. Also included are transcripts of Ockham's Razor, a show covering many different topics in which one "thoughtful [person] has [his or her] say without pesky interviewers interrupting." Time coverage varies, with some shows' transcripts dating back to 1995. The site also contains other program and pertinent information about this network, on the air since 1932.

1997-01-01

12

Corporate strategies for satellite communications  

NASA Astrophysics Data System (ADS)

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.

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

1991-10-01

13

The development of low-earth-orbit store-and-forward satellites in the Amateur Radio Service  

Microsoft Academic Search

The author discusses several satellites whose primary mission is to provide store-and-forward message relay services for radio amateurs. The primary focus is on the PACSAT-1 satellite owned and operated by the Radio Amateur Satellite Corporation of North America (AMSAT-NA), and the UoSAT-3 and UoSAT-5 satellites constructed and operated by the University of Surrey (England) UoSAT Spacecraft Engineering Research Unit. This

ROBERT J. DIERSING

1993-01-01

14

Attenuation and scintillation of radio waves in the Earth's atmosphere from radio occultation experiments on satellite-to-satellite links  

Microsoft Academic Search

A theoretical analysis of refractive loss of radio waves by the Earth's atmosphere in radio occultation measurements along the satellite-to-satellite line for various altitude profiles of the refractive index is given. Experimental results for refractive loss on the orbital spacecraft-geostationary satellite link are presented. Theoretical calculations are compared with experimental data, and a conclusion is drawn that the signal amplitude

O. I. Yakovlev; S. S. Matyugov; I. A. Vilkov

1995-01-01

15

Characteristics of the amateur radio means of the Arsene satellite  

Microsoft Academic Search

The Arsene (Ariane amateur radio satellite for space education) satellite is designed to provide amateur radio telecommunications services. Its equatorial orbit (20,000\\/36,000 km\\/0 deg) provides some 50 hours of continuous visibility by a radioamateur station. This radioamateur network will transmit in Packet AX25, SSB, and TTY modes and will provide voice transmission. In addition to the usual Very High Frequencies

Andre Cuisin

1992-01-01

16

Satellite observations of transient radio impulses from thunderstorms  

Microsoft Academic Search

Transient radio emissions from thunderstorms detected by satellites were first reported in 1995. The nature and source of these emissions remained a mystery until the launch of the FORTE satellite in 1997. FORTE, with its more sophisticated triggering and larger memory capacity showed that these emissions were connected to major thunderstorm systems. The analysis reported here, connecting FORTE RF events

P. E. Argo; M. Kirkland; A. Jacobson; R. Massey; D. Suszynsky; K. Eack; T. J. Fitzgerald; D. Smith

1999-01-01

17

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

Microsoft Academic Search

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

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

18

Direct broadcast satellite service by direct broadcast satellite corporation  

NASA Astrophysics Data System (ADS)

It is noted that common carrier operation implies the offer to transmit television programs or any other information in electronic form for any customer at a rate posted in a tariff recorded at the FCC and applied without discrimination. The satellite system developed must be flexible enough to provide virtually any transmision service its customers may decide to offer at some future time. This means that spot beams must be available, which will permit the programmer to concentrate his offerings on particular regions of the country. Also, with the first satellite, there will be full-coverage service to the entire contiguous United States; in this way, programmers wishing to reach a nationwide audience will be able to do so from the beginning of their DBS operation. In addition, there will be an effective isotropic radiated power level that is high enough to accommodate high-definition television. As a common carrier, it is also necessary to seek the maximum possible standardization of signal transmission formats, receiver and antenna characteristics, and satellite locations so that programmers wishing to provide either subscription-supported or advertiser-supported programs can reach the widest possible audiences.

Pritchard, W. L.; Radin, H. W.

1984-03-01

19

Low cost antennas for direct broadcast satellite radio  

Microsoft Academic Search

The direct broadcast satellite radio (DBSR) program is a joint effort between NASA and the United States Information Agency\\/Voice of America (USIA\\/VOA). DBSR will offer audio signals with various levels of sound quality (AM, FM, and CD) to reach a variety of radio receiver types (fixed, portable, and mobile) in various environments (indoor\\/outdoor, rural urban, and suburban). JPL has successfully

T. K. Wu; J. Huang

1994-01-01

20

FCC proposes sharing of weather satellite radio bands  

NASA Astrophysics Data System (ADS)

The Federal Communications Commission (FCC) has published a notice of a proposed ruling in the Federal Register that could lead to the licensing of millions of radio transmitters in the 1700-1710-MHz band. Transmission of data from meteorological satellites may be affected by this proposal: Since 1979, the National Oceanic and Atmospheric Administration (NOAA) has been using that band for satellite-to-earth transmission for the High-Resolution Picture Transmission (HRPT) program.

21

Attenuation and scintillation of radio waves in the Earth's atmosphere from radio occultation experiments on satellite-to-  

Microsoft Academic Search

A theoretical analysis of refractive loss of radio waves by the Earth's atmosphere in radio occultation measurements along the satellite-to-satellite line for various altitude profiles of the refractive index is given. Experimental results for refractive loss on the orbital spacecraft - geostationary satellite link are presented. Theoretical calculations are compared with experimental data, and a conclusion is drawn that the

O. I. Yakovlev; I. A. Vilkov

1995-01-01

22

Radio wave propagation measurements for land-mobile satellite systems at 2.33 GHz  

Microsoft Academic Search

The performance of a mobile satellite communications link is dominated by roadside attenuation due to vegetation or manmade structures. Previous measurement campaigns characterized land-mobile satellite channels at UHF and L bands. In 1997, the FCC allocated S-band spectrum to the Digital Audio Radio Satellite (DARS) service to provide nationwide radio services to the North American continent via satellite. This article

L. Mousselon; R. M. Barts; S. Licul; G. Joshi

2003-01-01

23

Scintillation and Absorption of Radio Waves in the Earth's Atmosphere in Radio Occultation Experiments on the Satellite-to-Satellite Link  

Microsoft Academic Search

A radio occultation experiment where both transmitter and receiver are above troporpheric characteristic altitudes and at long distances from each other has been performed. Results from such a satellite-to-satellite link are analyzed.

I. A. Vilkov; S. S. Matyugov; O. I. Yakovlev

1996-01-01

24

Modeling GNSS Radio Occultation coverage from various satellite constellation configurations  

NASA Astrophysics Data System (ADS)

We present results of simulations of measurement strategies for satellites tracking radio occultations for weather and climate prediction. The results of these simulations are being used to help design satellite constellation geometries and receiver capabilities. Weather and climate prediction require robust sampling of the state of the atmosphere. Observations from satellites in low Earth orbit tracking occulting Global Navigation Satellite System (GNSS) signals as those signals transit the atmosphere can be inverted to yield the refractive index as a function of height. The refractive index can then be interpreted in terms of atmospheric temperature in the upper atmosphere or as water vapor content in the lower troposphere. (Hajj et al 2002) Constellations with multiple inclinations provide the best observing geometry. Radio occultation receivers on missions of opportunity can add to the overall coverage in a very cost effective way. Future receivers should be able to track GPS, Galileo, and other GNSS signals to make maximum use of the orbiting platform, and should be able to track multiple occulting signals simultaneously. One example of a coverage map for a constellation of 3 satellites at 70 degrees, 3 at 25 degrees, and 2 polar Decadal Survey missions of opportunity is shown below. Hajj, G. A., E. R. Kursinski, L. J. Romans, W. I. Bertiger, and S. S. Leroy (2002), A technical description of atmospheric sounding by GPS occultation, J. Atmos. Sol. Terr. Phys., 64, 451-469, doi:10.1016/S1364-6826 (01)00114-6.

Hurst, K. J.; Heeg, C.; Mannucci, A. J.

2010-12-01

25

Australis Oscar V - An Australian amateur radio satellite  

Microsoft Academic Search

An account is given of the design features and operational history of the 'Australis' Australian-built amateur radio satellite of NASA 'Oscar' type, which was launched into a nearly circular orbit of 500-mile altitude in January, 1970, and operated for the three-month period that its battery was designed to sustain. A total of 15 Australian companies and institutions contributed to this

R. Tonkin; O. Mace

1987-01-01

26

Development of radio seeing monitor using LEO satellite beacons  

NASA Astrophysics Data System (ADS)

To monitor the atmospheric conditions in the radio astronomical observations, we have developed a new type of the radio seeing monitor, which enables us to measure the atmospheric turbulence in real-time and in a wide range of the direction in the celestial hemisphere. The base of the measurement system is a radio interferometer, in which the beacon waves of low earth orbit satellites (LEO satellites) for mobile communication system are received as reference signals. Time variations of the differences in arrival time are measured between element antennas of the interferometer, which are given as phase variations of cross-power spectra of the signals received by the antennas. we have made test observations of the atmospheric disturbances, and obtained a typical profile that the magnitude of the phase variations tends to increase with decreasing elevation angle of the reference source, i.e., the LEO satellite. In addition, we found that the magnitude of the phase variations is locally enhanced in some directions.

Nishio, Masanori; Suzuyama, Tomonari; Kohashiguchi, Hiroshi; Miyazaki, Tomoyuki; Sumino, Yoshio; Ando, Takafusa; Hirata, Masako; Liu, Qinghui

2002-11-01

27

Fade durations in satellite-path mobile radio propagation  

NASA Astrophysics Data System (ADS)

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.

Schmier, Robert G.; Bostian, Charles W.

1986-12-01

28

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

NASA Astrophysics Data System (ADS)

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.

Hollansworth, James E.

1993-06-01

29

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

NASA Astrophysics Data System (ADS)

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.

Hollansworth, James E.

30

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

NASA Astrophysics Data System (ADS)

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.

Hollansworth, James E.

31

Measurements of Radio Star and Satellite Scintillations at a Subauroral Latitude  

Microsoft Academic Search

Observations of two radio stars, Cygnus A and Cassiopeia A, and of two satellites, Cosmos I and Transit 4A, have yielded data on lower and upper atmospheric irregularities. The frequencies studied have included 20 Mc, 40 Mc and 54 Mc for satellite transmissions, and 30 Mc to 3000 Mc for radio star signals. The antennas used have ranged from a

R. S. Allen; J. Aarons; H. Whitney

1964-01-01

32

Measurements of radio star and satellite scintillations at a subauroral latitude  

Microsoft Academic Search

Observations of two radio stars, Cygnus A and Cassiopeia A, and of two satellites, Cosmos I and Transit 4A, have yielded data on lower and upper atmospheric irregularities. The frequencies studied have included 20 Mc, 40 Mc and 54 Mc for satellite transmissions, and 30 Mc to 3000 Mc for radio star signals. The antennas used have ranged from a

R. S. ALLEN; J. Aarons; H. Whitney

1964-01-01

33

Measurements of transionospheric radio propagation parameters using the FORTE satellite  

NASA Astrophysics Data System (ADS)

We report initial measurements of ionospheric propagation parameters, particularly the total electron content (TEC), using the recently launched FORTE satellite. FORTE, which orbits the Earth at an altitude of 800 km and an inclination of 70°, contains a set of wideband radio receivers whose output is digitally recorded. A specialized triggering circuit identifies transient, broadband radio events, which include radiation from lightning, transionospheric pulse pairs, and man-made sources. Event data are transmitted to the ground station for analysis. In this paper we examine signals transmitted from an electromagnetic pulse generator operated at Los Alamos. The transmitter produces nearly impulsive signals in the VHF range. The received signal is dispersed by the ionosphere, and the received signal can be analyzed to deduce the total electron content along the path. By comparing the slant TEC thus measured with results from a ray-tracing code, we can deduce the vertical TEC to 800 km. Data from eight passes are presented. These types of data (in larger quantities) are of interest to operators of radar altimeters, who need data to corroborate their corrections for the ionospheric TEC. The combination of FORTE TEC data to 800 km and TEC measurements to 20,000 km (the Global Positioning System orbital altitude) can provide useful information for assessing the validity of models of plasmaspheric electron density. Initial estimates of the plasmaspheric density, on two daytime passes, are about 6 TECU. The signal received by FORTE, which is linearly polarized at the transmitter, is split into two magnetoionic modes by the ionosphere. The receiving antenna is also linearly polarized and therefore receives both modes. By measuring the beat frequency between the two modes, we can deduce the product of the geomagnetic field and the cosine of the angle between the field and the propagation vector. The possibility of using the measured slant TEC and the beat frequency to geolocate impulsive signals is discussed.

Massey, Robert S.; Knox, Stephen O.; Franz, Robert C.; Holden, Daniel N.; Rhodes, Charley T.

1998-11-01

34

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

ERIC Educational Resources Information Center

|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…

Pizzi, Skip

35

Ionospheric Heating by Radio Waves: Predictions for Arecibo and the Satellite Power Station  

Microsoft Academic Search

The effect of resistive heating by radio waves on ionospheric temperatures, electron densities, and airglow emissions is examined by using numerical ionospheric structure and heat balance codes. Two cases are studied: (1) a 3-GHz, 10-GW microwave beam from a proposed satellite power station and (2) IMW and 3-MW beams of 15-MHz radio waves launched by the Arecibo antenna. By intent,

F. W. Perkins; R. G. Roble

1978-01-01

36

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

ERIC Educational Resources Information Center

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…

Pizzi, Skip

37

Enhanced Specification of the Equatorial Ionospheric Scintillation Environment with Satellite Radio Beacons  

Microsoft Academic Search

Remote sensing of radio signals from low-Earth orbiting (LEO) satellites provides a wealth of information on the presence and location of disturbances in the equatorial ionosphere which result in scintillations. Results will be presented emphasizing the statistical improvements provided to existing ionospheric specification models with the assimilation of measurements from the Coherent Electromagnetic Radio Tomography (CERTO) beacon onboard the Communication\\/Navigation

R. G. Caton; K. M. Groves; M. Verlinden

2010-01-01

38

Measurements of Radio Star and Satellite Scintillations at a Subauroral Latitude.  

National Technical Information Service (NTIS)

Observations of two radio stars, Cygnus A and Cassiopeia A, and of two satellites, Cosmos I and Transit 4A, have yielded data on lower and upper atmospheric irregularities. The frequencies studied have included 20 Mc, 40 Mc and 54 Mc for satellite transmi...

R. S. Allen J. Aarons H. Whitney

1964-01-01

39

Using commercial satellites for buoy-based remote radios  

Microsoft Academic Search

This paper discusses the primary issues of using a satellite for a buoy-based remote repeater system, specifically, how to apply the antenna's beam width, pedestal motion and potential interference with other satellites to give a first cut in the selection of a commercial satellite system

D. Rickerson; M. Rhoads

1995-01-01

40

Communications services provided by the PACSAT-1, UOSAT-5, and KITSAT-1 amateur radio satellites  

Microsoft Academic Search

While many proposals to provide communications services via low-Earth-orbit (LEO) satellites have been appearing in the literature, engineers, researchers, and experimenters in the amateur radio service have been advancing the state of the art in single LEO store-and-forward satellite design and application. The scope of this paper will be limited to the PACSAT-1, UOSAT-5, and KITSAT-1 satellites, whose primary mission

Robert J. Diersing

1993-01-01

41

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

ERIC Educational Resources Information Center

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…

Lee, William E.

42

Satellite augmentation of cellular type mobile radio telephone systems  

NASA Astrophysics Data System (ADS)

An experiment in which the ATS-6 satellite relayed voice bandwidth communications between five trucks and the trucking company dispatchers as the trucks traveled about the northeastern part of the U.S. is described. The experiment demonstrated that propagation characteristics are much different for the satellite-mobile links than for terrestrial-mobile links. It is found that a properly designed satellite system can provide high quality, reliable voice and data communications except where the vehicle-satellite path is shadowed by a structure or terrain feature.

Anderson, R. E.

1981-09-01

43

Cassini Measurements of Satellite Influence on Jupiter's Radio Emission  

NASA Astrophysics Data System (ADS)

Jupiter decameter wavelength emissions (DAM) have a known correlation with the orbital phases of the four Galilean satellites. In particular, the 2.0-5.6 MHz band of the DAM emission shows a small but significant enhancement in occurrence probability at specific orbital phases of the satellites. We performed a similar study using Cassini data that includes rotation period averaging and removal of the known satellite influences. We confirm the Galileo and Voyager studies in the 2.0-5.6 MHz band of the DAM emission and investigate the higher frequency bands 6-16 MHz. These analyses give further evidence for Alfvénic interactions between the satellites and Jupiter.

Higgins, C.; Mason, P.

2007-05-01

44

Ionospheric heating by radio waves - Predictions for Arecibo and the satellite power station  

Microsoft Academic Search

The effect of resistive heating by radio waves on ionospheric temperatures, electron densities, and airglow emissions is examined by using numerical ionospheric structure and heat balance codes. Two cases are studied: a 3-GHz, 10-GW microwave beam from a proposed satellite power station and 1-MW and 3-MW beams of 15-MHz radio waves launched by the Arecibo antenna. The most dramatic heating

F. W. Perkins; R. G. Roble

1978-01-01

45

Prospects for Lunar Satellite Detection of Radio Pulses from Ultrahigh Energy Neutrinos Interacting with the Moon  

SciTech Connect

The Moon provides a huge effective detector volume for ultrahigh energy cosmic neutrinos, which generate coherent radio pulses in the lunar surface layer due to the Askaryan effect. In light of presently considered lunar missions, we propose radio measurements from a Moon-orbiting satellite. First systematic Monte Carlo simulations demonstrate the detectability of Askaryan pulses from neutrinos with energies above 10{sup 20} eV at the very low fluxes predicted in different scenarios.

Staal, O. [Swedish Institute of Space Physics, P.O. Box 537, SE-751 21 Uppsala (Sweden); High Energy Physics, Uppsala University, P.O. Box 535, SE-751 21 Uppsala (Sweden); Bergman, J. E. S. [Swedish Institute of Space Physics, P.O. Box 537, SE-751 21 Uppsala (Sweden); Thide, B.; Daldorff, L. K. S. [Swedish Institute of Space Physics, P.O. Box 537, SE-751 21 Uppsala (Sweden); LOIS Space Centre, Vaexjoe University, SE-351 95 Vaexjoe (Sweden); Ingelman, G. [High Energy Physics, Uppsala University, P.O. Box 535, SE-751 21 Uppsala (Sweden)

2007-02-16

46

ESA satellite wideband CDMA radio transmission technology for the IMT2000\\/UMTS satellite component: features and performance  

Microsoft Academic Search

The European Telecommunication Standards Institute (ETSI) decision to endorse for the Universal Telecommunication Radio Access (UTRA) techniques based upon wideband CDMA approaches for terrestrial UMTS (T-UMTS) paired frequency duplexing band will certainly constitute an important driver to steer the corresponding choice for the satellite UMTS (S-UMTS) component. In this paper it is shown how a similarity in the S-UMTS access

R. De Gaudenzi; G. Gallinaro; G. Caire; R. Lyons; M. Luglio; M. Ruggieri; A. Vernucci; H. Widmer

1999-01-01

47

Low-Earth-orbit store-and-forward satellites in the amateur radio service  

Microsoft Academic Search

The authors review the current state of the art in amateur radio store-and forward satellite communications. Several operating satellite systems are described along with the procedures, equipment, and software required to access them. For PACSAT-1 empirical data have been used to estimate a downlink bit error probability of 6.0E-5. A further description of downlink performance is given through the examination

Robert J. Diersing; Greg Jones

1992-01-01

48

A Correction Method of Orbit Elements Using Amateur Radio Facilities for Nano-Satellites  

Microsoft Academic Search

A correction method of orbit elements for nano-satellites using simple and low cost facilities is required. In this study, the Doppler shift of the beacon signal from a cubesat was observed using an amateur radio. The history of frequency variation was recorded for different TLEs with different epoch time. The frequency difference translated into seconds (FDTS) was deduced as a

Yasuhisa Oda; Shinichi Nakasuka; Priya Fernando

2008-01-01

49

A Remote Satellite-Linked Tracking System for Studying Pacific Salmon with Radio Telemetry  

Microsoft Academic Search

A remote tracking system with a satellite uplink was used to study the movements of adult chinook salmon Oncorhynchus tshawytscha and coho salmon O. kisutch in the large, isolated Taku River in Alaska and British Columbia. Salmon were tagged with pulse-coded radio trans- mitters; 10 codes identified individual fish on each of 52 frequencies. Remote tracking stations automatically collected, processed,

JOHN H. EILER

1995-01-01

50

Direct Broadcast Satellite-Radio Market, Legal, Regulatory, and Business Considerations.  

National Technical Information Service (NTIS)

A Direct Broadcast Satellite-Radio (DBS-R) System offers the prospect of delivering high quality audio broadcasts to large audiences at costs lower than or comparable to those incurred using the current means of broadcasting. The maturation of mobile comm...

D. R. Sood

1991-01-01

51

Direct broadcast satellite-radio market, legal, regulatory, and business considerations  

Microsoft Academic Search

A Direct Broadcast Satellite-Radio (DBS-R) System offers the prospect of delivering high quality audio broadcasts to large audiences at costs lower than or comparable to those incurred using the current means of broadcasting. The maturation of mobile communications technologies, and advances in microelectronics and digital signal processing now make it possible to bring this technology to the marketplace. Heightened consumer

Des R. Sood

1991-01-01

52

Wideband Radio Wave Observations of Lightning Discharge by Maido-1 Satellite  

NASA Astrophysics Data System (ADS)

Maido-1 satellite was launched on 23 January 2009. The satellite carries the radio-frequency payload, Broadband Measurement of Waveform for VHF Lightning Impulses (VHF sensor), for research on lightning discharges. The final goal of our research is to locate sources of impulsive VHF radiation from lightning discharges and constantly monitor lightning activity from space. Maido-1 satellite has the aim of proving the functions of the sensor in space and to study the radio propagation characteristics of the ionosphere. Through the operation/observation for 5 months, more than 10, 000 VHF signals have been recorded. The locations where VHF signals are detected and the examples of the received waveforms are presented in this paper. We discuss the regional dependency of the received signals.

Kikuchi, Hiroshi; Morimoto, Takeshi; Ushio, Tomoo; Kawasaki, Zen

53

An efficient demand-assignment multiple-access scheme for satellite mobile radio dispatch networks  

NASA Astrophysics Data System (ADS)

Conventional demand-assignment multiple access (DAMA) designs process mobile radio calls in much the same way as mobile telephone calls. In mobile radio dispatch networks, where the dispatcher is often the resource bottleneck, these designs result in the inefficient use of satellite channels. A novel DAMA design is presented that ameliorates this problem by using the block-calls-queued service discipline, batched processing of several calls by the network dispatcher, and pipelined messaging for channel setup verification. Analysis shows that the proposed design offers advantages in satellite channel utilization and DAMA signaling overhead compared to previous designs. As space segment resources are expected to be very expensive in the mobile satellite systems networks under development, the proposed procedures could result in significant cost savings.

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

1989-11-01

54

In-class demonstration using amateur radio satellites for the teaching of communications engineering at the Universiti Kebangsaan Malaysia  

Microsoft Academic Search

One of the most readily available demonstrations for teaching communications engineering is the amateur radio satellites orbiting the Earth. There are several advantages to using amateur satellites for classroom demonstration. The positions of the satellites are predictable, and, unlike terrestrial communications, the links are generally line of sight and more reliable. In general, the effects of the ionosphere are very

A. F. M. Zain

1994-01-01

55

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

Microsoft Academic Search

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

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

1984-01-01

56

Solar Paddle Antenna on Pico-Satellite for Amateur Radio Communication  

NASA Astrophysics Data System (ADS)

This paper describes solar paddle antenna proposed in the development of Kagawa Satellite "KUKAI." KUKAI is a mother-daughter pico-satellite for technical verification of a tethered space robot. The mother and the daughter satellites communicate respectively with the ground station by amateur radio frequencies. For the purpose of simple deployment system on orbit and antenna directivity suitable for KUKAI, solar paddle antenna mounted at the edge of a solar paddle is employed. After sufficient antenna adjustment on the ground, KUKAI was launched on 23 January 2009 by the H-IIA rocket from Tanegashima Space Center. The solar paddles were successfully deployed, and communication by the solar paddle antenna was successful.

Nohmi, Masahiro; Oi, Katsumi; Takuma, Satoshi; Ogawa, Masaaki

57

Application of frequency and space correlation of radio wave propagation conditions for the purpose of designing satellite communications links  

Microsoft Academic Search

The present consideration of the influence of rain effect prediction methods on 10-30 GHz frequency range satellite communications links gives attention to the possible application of the frequency and space correlation of radio wave propagation on earth-satellite paths. Different evaluation methods are discussed in light of results obtained by propagation experiments conducted under the Intercosmos program. Agreement is noted to

B. Balabanov; E. Aleksandrova; V. Sviatogor; V. Bykov; A. Kavetzki

1987-01-01

58

Study of sub-auroral radio emissions observed by ICE experiment onboard DEMETER satellite  

NASA Astrophysics Data System (ADS)

We report on the terrestrial kilometric and hectometric radio emissions recorded by the DEMETER/ICE (Instrument Champ Electrique) experiment. This instrument measures the electric field components of electromagnetic and electrostatic waves in the frequency range from DC to 3.25 MHz. Despite the limited satellite invariant latitude (data acquisition below about 65°), specific events have been observed, close to the sub-auroral region, in the frequency range from 100 kHz to about 1 MHz. This range covers the well-known auroral kilometric radiation (AKR), the terrestrial kilometric continuum, and the sub-auroral terrestrial emission at higher frequency up to 3 MHz. The high spectral capability of the experiment leads us to distinguish between the bursty and the continuum emissions. Selected events have been found to principally occur in the late evening and early morning sectors of the magnetosphere (22 MLT - 02 MLT) but others have been observed on the dayside. Our first results are compared to previous radio observations performed on board INTERBALL-1 (Kuril'chik et al, Cosmic Research, 43, 2005) and GEOTAIL (Hashimoto et al., JGR, 104, 1999) satellites. We also discuss the common and different features of the Earth and Jovian radio emissions. We emphasis on the observational parameters: the occurrence probability, the emission beam and the spectral emission types. We show that the physical interpretation of the auroral phenomena needs a good knowledge of the geometric configuration of the source and observer and the reception system (antenna beam and receivers).

Boudjada, M. Y.; Galopeau, P. H. M.; Mogilevski, M. M.; Sawas, S.; Blecki, J.; Berthelier, J. J.; Voller, W.

2012-04-01

59

Observations of the auroral hectometric radio emission onboard the INTERBALL-1 satellite  

NASA Astrophysics Data System (ADS)

The results of five-year (1995 2000) continuous observations of the auroral radio emission (ARE) in the hectometric wavelength range on the high-apogee INTERBALL-1 satellite are presented. Short intense bursts of the auroral hectometric radio emission (AHR) were observed at frequencies of 1463 and 1501 kHz. The bursts were observed predominantly at times when the terrestrial magnetosphere was undisturbed (in the quiet Sun period), and their number decreased rapidly with increasing solar activity. The bursts demonstrated seasonal dependence in the Northern and Southern hemispheres (dominating in the autumn-winter period). Their appearance probably depends on the observation time (UT). A qualitative explanation of the AHR peculiarities is given.

Kuril'Chik, V. N.

2007-06-01

60

A Correction Method of Orbit Elements Using Amateur Radio Facilities for Nano-Satellites  

NASA Astrophysics Data System (ADS)

A correction method of orbit elements for nano-satellites using simple and low cost facilities is required. In this study, the Doppler shift of the beacon signal from a cubesat was observed using an amateur radio. The history of frequency variation was recorded for different TLEs with different epoch time. The frequency difference translated into seconds (FDTS) was deduced as a ratio of the maximum frequency variation in the pass to the 1s-periodic variation. The FDTS has dependency on TLE. For the old TLE, the FDTS was larger than the new one. Because the FDTS is related to satellite's phase variation in the orbit, the TLE's epoch time was corrected using the measurement result. The FDTS with the observation using the corrected TLE was small.

Oda, Yasuhisa; Nakasuka, Shinichi; Fernando, Priya

61

Satellite control of Jovian 2-6 MHz radio emission using Voyager data  

NASA Astrophysics Data System (ADS)

Jupiter's satellite Io no longer has the only known effect in controlling the low-frequency Jovian radio emissions. Menietti et al. (1998, 2001) used a long and contiguous set of data in the range of 2.0-5.6 MHz from the Galileo spacecraft and found correlations with the orbital phase of Ganymede and Callisto. Recently, Higgins et al. (2006) used all of the Galileo orbiter data and found that Europa's phase shows a minor but statistically significant effect on the lower range of decametric emissions. In this paper, results are found that confirm previous work for all four Galilean satellites by combining Voyager 1 and Voyager 2 flyby data in the frequency range of 2.1-5.8 MHz. The data were analyzed using the unique occurrence probability data compilation technique that includes 10-hour averaging and satellite bias removal. A statistical significance Z-test was computed to compare sample populations for each enhanced region of occurrence against the background. We find significance values greater than the 95% confidence level (Z > 2?) for Io, Europa, Ganymede, and Callisto. Least squares fits to histograms of relative occurrence probability also show similar results. The cause of these correlations is believed to be Alfvénic interactions between the individual satellite and Jupiter.

Higgins, C. A.

2007-05-01

62

The evolution of satellite-monitored radio tags for large whales: One laboratory's experience  

NASA Astrophysics Data System (ADS)

Despite several centuries of whaling and directed research, there are only a few whale stocks whose year-round whereabouts are reasonably well known. For the vast majority of depleted populations, the link between seasonal feeding and breeding concentrations remains unknown. This lack of information on range, seasonal distribution, stock structure, and migration routes makes it difficult to design and implement effective conservation measures to promote recovery. The use of such information would have been valuable to develop stock-specific quotas for whaling, but now it may be even more important for recovery of depleted stocks and identifying anthropogenic threats throughout a depleted stock's range. Building upon the preliminary findings of Discovery tags and more recent photo identification studies, satellite-monitored radio tags are now providing range and seasonal distribution information for many stocks of depleted large whales. These parameters are important to better estimate population abundance, characterize habitats, identify threats to recovery, and design effective protection measures when needed. This paper traces one laboratory's experience with the development of satellite-monitored radio tag technology for large whales, including attachment mechanisms and delivery systems, in the hope that others will profit from our successes and our mistakes. Selected examples are used to demonstrate how such tags contribute to new insights about whales' habitats, migrations, behaviour, and management.

Mate, Bruce; Mesecar, Roderick; Lagerquist, Barbara

2007-02-01

63

Effects of the ionosphere and solar activity on radio occultation signals: Application to CHAllenging Minisatellite Payload satellite observations  

Microsoft Academic Search

We analyze the ionospheric effect on the phase and amplitude of radio occultation (RO) signal. The introduced theoretical model predicts a correlation between the phase acceleration and intensity variations of RO signal and opens a way to locate layered structures in the propagation medium, in particular, in trans-ionospheric satellite-to-satellite links. For considered CHAllenging Minisatellite Payload (CHAMP) RO events, the locations

A. G. Pavelyev; Y. A. Liou; J. Wickert; T. Schmidt; A. A. Pavelyev; S. F. Liu

2007-01-01

64

Voyager 2 radio science observations of the uranian system: atmosphere, rings, and satellites.  

PubMed

Voyager 2 radio occultation measurements of the Uranian atmosphere were obtained between 2 and 7 degrees south latitude. Initial atmospheric temperature profiles extend from pressures of 10 to 900 millibars over a height range of about 100 kilometers. Comparison of radio and infrared results yields mole fractions near the tropopause of 0.85 and 0.15 +/- 0.05 for molecular hydrogen and helium, respectively, if no other components are present; for this composition the tropopause is at about 52 kelvins and 110 millibars. Distinctive features in the signal intensity measurements for pressures above 900 millibars strongly favor model atmospheres that include a cloud deck of methane ice. Modeling of the intensity measurements for the cloud region and below indicates that the cloud base is near 1,300 millibars and 81 kelvins and yields an initial methane mole fraction of about 0.02 for the deep atmosphere. Scintillations in signal intensity indicate small-scale stucture throughout the stratosphere and upper troposphere. As judged from data obtained during occultation ingress, the ionosphere consists of a multilayer structure that includes two distinct layers at 2,000 and 3,500 kilometers above the 100-millibar level and an extended topside that may reach altitudes of 10,000 kilometers or more. Occultation measurements of the nine previously known rings at wavelengths of 3.6 and 13 centimeters show characteristic values of optical depth between about 0.8 and 8; the maxim value occurs in the outer region of the in ring, near its periapsis. Forward-scattered signals from this ring have properties that differ from those of any of Saturn's rings, and they are inconsistent with a discrete scattering object or local (three-dimensional) assemblies of orbiting objects. These signals suggest a new kdnd of planetary ring feature characterized by highly ordered cylindrical substructures of radial scale on the order of meters and azimuthal scale of kilometers or more. From radio data alone the mass of the Uranian system is GM(sys) = 5,794,547- 60 cubic kilometers per square second; from a combination of radio and optical navigation data the mass of Uranus alone is GM(u) = 5,793,939+/- 60 cubic kilometers per square second. From all available Voyager data, induding imaging radii, the mean uncompressed density of the five major satellites is 1.40+/- 0.07 grams per cubic centimeter; this value is consistent with a solar mix of material and apparently rules out a cometary origin of the satellites. PMID:17812893

Tyler, G L; Sweetnam, D N; Anderson, J D; Campbell, J K; Eshleman, V R; Hinson, D P; Levy, G S; Lindal, G F; Marouf, E A; Simpson, R A

1986-07-01

65

Overview of Cassini radio science at Saturn, Titan, and the icy satellites  

NASA Astrophysics Data System (ADS)

The Cassini spacecraft which has been in orbit about Saturn for over two years is the first Radio Science platform to provide three downlink frequencies In addition to the X-band telemetry link 3 56 cm w l two other frequencies S-band 13 04 cm and Ka-band 0 94 cm are available This plus the high SNR 50 dBHz at X-band afforded by the 4 m diameter s c high gain antenna in combination with the excellent low noise receivers of the DSN as well as overall system stabilities of 1 part in 10 13 when referenced to the on-board ultra-stable oscillator USO in one-way operation and 1 part inx 10 15 for a two-way link make Cassini an unprecedented instrument of radio science The orbital tour phase of the mission has the following main radio science objectives a determination of the masses and gravity fields of Saturn s icy satellites Titan and Saturn through two-way tracking during fly-bys To date the masses of Phoebe Iapetus Dione Enceladus Rhea and Titan have been measured and will be reported here b Measurement of the structure and other properties of Saturn s rings through three-band occultation Seven near-diametric occultations at a high ring opening angle have been completed and the results will be presented here c Measurement of the vertical structure of the atmosphere and ionosphere of Saturn The same series of occultations have provided nearly equatorial observations of the atmosphere structure and the ionosphere and the results will be described here d Measurement of the vertical structure of

Kliore, A. J.; Ambrosini, R.; Armstrong, J. W.; Flasar, F. M.; French, R. G.; Iess, L.; Marouf, E. A..; Nagy, A. F.; Rappaport, N. J.; Tortora, P.; Jpl/Dsn Radio Science Support Team

66

Radio vision of the vertical structure of the layers and a study of radio-wave propagation conditions in the atmosphere using high-stability satellite signals  

Microsoft Academic Search

From an analysis of the CHAMP (Germany) and FORMOSAT-3 (Taiwan–USA) satellite data it follows that the second-order time derivative\\u000a of the eikonal (eikonal acceleration) and the Doppler frequency shift are two most important parameters indispensable for\\u000a the radio vision of layers in the atmosphere and the ionosphere. Measurements of the temporal evolution of the Doppler shift\\u000a permit one to study

A. G. Pavelyev

2009-01-01

67

Satellites  

SciTech Connect

The present work is based on a conference: Natural Satellites, Colloquium 77 of the IAU, held at Cornell University from July 5 to 9, 1983. Attention is given to the background and origins of satellites, protosatellite swarms, the tectonics of icy satellites, the physical characteristics of satellite surfaces, and the interactions of planetary magnetospheres with icy satellite surfaces. Other topics include the surface composition of natural satellites, the cratering of planetary satellites, the moon, Io, and Europa. Consideration is also given to Ganymede and Callisto, the satellites of Saturn, small satellites, satellites of Uranus and Neptune, and the Pluto-Charon system.

Burns, J.A.; Matthews, M.S.

1986-01-01

68

Protection of passive radio frequencies used for earth exploration by satellite  

NASA Astrophysics Data System (ADS)

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.

Rochard, Guy

2004-10-01

69

Direct broadcast satellite-radio market, legal, regulatory, and business considerations  

NASA Astrophysics Data System (ADS)

A Direct Broadcast Satellite-Radio (DBS-R) System offers the prospect of delivering high quality audio broadcasts to large audiences at costs lower than or comparable to those incurred using the current means of broadcasting. The maturation of mobile communications technologies, and advances in microelectronics and digital signal processing now make it possible to bring this technology to the marketplace. Heightened consumer interest in improved audio quality coupled with the technological and economic feasibility of meeting this demand via DBS-R make it opportune to start planning for implementation of DBS-R Systems. NASA-Lewis and the Voice of America as part of their on-going efforts to improve the quality of international audio broadcasts, have undertaken a number of tasks to more clearly define the technical, marketing, organizational, legal, and regulatory issues underlying implementation of DBS-R Systems. The results and an assessment is presented of the business considerations underlying the construction, launch, and operation of DBS-R Systems.

Sood, Des R.

1991-03-01

70

Direct Broadcast Satellites: An Interview with Hartford Gunn.  

ERIC Educational Resources Information Center

|In this interview with Hartford Gunn, Vice-President of Program Development for Satellite Television Corporation (STC), the concept of direct broadcast by satellite (DBS) is explored. Allocation of radio frequencies, services provided by DBS network, home installation and purchase of dish antenna, and comparison of DBS with cable television are…

Library Hi Tech, 1984

1984-01-01

71

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

Microsoft Academic Search

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

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

72

Computation of the key parameters of radio signals propagating through a perturbed ionosphere in the land-satellite channel  

NASA Astrophysics Data System (ADS)

An analysis of the key parameters of HF/UHF radio signals was carried out for land-satellite radio channels, which determine the effects of fading in a perturbed ionosphere. Using the parameters of the perturbed plasma, the effects of the absorption and phase fluctuations of radio signals are analyzed for a channel with fading. For the evaluation of the effect of scattering of a radio signal by ionospheric inhomogeneities in an approximation of small-scale scintillations, expressions for the root-mean-square (RMS) magnitude of signal intensity and phase scintillations are presented. Scintillation index ?{/I 2} that corresponds to variations in a signal under the conditions of multipath propagation with fading is investigated by using experimental data. It is shown that roughly ˜10% of inhomogeneities of the electron concentration in the F region of the ionosphere, perturbed during a magnetic storm, yield strong quickly fading radio signals in the VHF/UHF range with significant fluctuations (up to 1%) in the intensity of the signal and phase fluctuations (up to hundreds of radians). The calculated magnitudes of the scintillation index are in good agreement with experimentally observed data.

Blaunstein, N.; Pulinets, S. A.; Cohen, Y.

2013-04-01

73

Precise line-of-sight vector estimation based on an inter-satellite radio frequency system  

NASA Astrophysics Data System (ADS)

This paper proposes a precise line-of-sight (LOS) vector estimation using an inter-satellite radio frequency system. GNSS-like technology is inherited such that the ranging signals are locally generated inside the formation. However, the approach differs from the standard GNSS model usage in that the LOS vector to be of a unit length is fully explored as a priori constraint for the carrier phase integer ambiguity resolution. The constraint is lumped to the mapping process from the real-valued ambiguities to the integers by what is called validation or subset ambiguity bounding. These two approaches have the same rules of regarding the constraint as a gateway to accept or reject the ambiguity candidates, but differ by using "all-ambiguity-set" and "subset-ambiguity". Both show remarkable improvement with up to 80% lower integer fixing failure rates than without treating the constraint. Validation provides a slightly better performance than the subset ambiguity bounding in terms of the integer fixing failure rates and the computational efficiency. The predefined tolerance regions that are critical for these two methods are analytically determined as function of the carrier noise. The paper also introduces a LOS dependent ambiguity dilution of precision (ADOPLOS) measure that can serve as a metric to characterize the expectation of being able to successfully resolve the ambiguities. The region of ADOPLOS lower than 0.21 is empirically summarized as the safe region where the integer fixing failure rates are less than 1%. A closed form of the ADOPLOS is derived which is able to capture the impact of the various factors. Antenna baseline geometries and multiple frequencies in the form of an ultra-BOC signal structure are demonstrated as the most important influencing factors. With multiple properly arrayed antennas and using ultra-BOC structure, instantaneous ambiguity resolution can be achieved and the LOS accuracy can reach millimeter level.

Sun, R.; Guo, J.; Gill, E.

2013-04-01

74

Radio wave propagation studies along an Earth-space satellite link  

Microsoft Academic Search

The use of superhigh microwave frequencies for satellite communications has many advantages, but its major drawback lies in the effects of atmospheric hydrometeors on electromagnetic wave propagation. One research effort under way to investigate this problem is being conducted by the European Space Agency, which will launch the Olympus-1 communications satellite in June 1989. One of this satellite's four payloads

Jacques Albert

1990-01-01

75

The ABC switches on the satellite  

Microsoft Academic Search

The Australian Broadcasting Corporation (ABC) is planning to use Aussat for the on-air mixing of TV and radio programs for inter-studio program interchange. Used in conjunction with Aussat and ABC-owned earth station facilites, the Satellite Network Control System will provide substantially increased programming flexibility for both radio and TV. This system is described with emphasis on function, the control concept,

G. O'Sullivan; G. Brown

1986-01-01

76

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

NASA Astrophysics Data System (ADS)

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 foreseen for radar studies between 5MHz and 50MHz. While the high frequencies (above ˜40 MHz) are clean bands since natural jovian radio emissions show a high frequency cutoff at about 40 MHz, lower frequencies are right in the middle of the intense decametric (DAM) radio emissions. We present a review of spectral intensity, variability and sources of these radio emissions. As the radio emission are 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. One result from these simulations is that some portion of the orbit of Europa is clean from Non-Io DAM emissions above 22 MHz. We also review the radiation belts synchrotron emission characteristics. This study clearly shows that a deep understanding of the natural radio emissions at Jupiter is necessary to prepare the future EJSM radar instrumentation.

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

2010-12-01

77

Low Earth-orbit store-and-forward satellites in the amateur radio service  

Microsoft Academic Search

Several aspects of the most recently launched low-earth-orbit (LEO) store-and-forward satellites operating in the amateur satellite service are described. Included are a description of the satellites and their most interesting implementation details, with particular emphasis on the communications system; a description of the file server and broadcast protocol; a description of operation from the user's viewpoint; and some statistics characterizing

Robert J. Diersing; Greg Jones

1993-01-01

78

The CERTO and CITRIS Instruments for Radio Scintillation and Electron Density Tomography from the C/NOFS, COSMIC, NPSAT1 and STPSAT1 Satellites  

NASA Astrophysics Data System (ADS)

A new constellation of radio beacon and radio beacon receivers will be providing global measurements of radio scintillations and total electron content (TEC) for near real time measurements of the ionosphere. This constellation is comprised of the NRL Coherent Electromagnetic Radio Tomography (CERTO) beacons on the Communications/Navigation Forecast Outage System (C/NOFS) satellite, the six Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) satellites, and the Naval Postgraduate (NPSAT1) Satellite. These satellites will be launched in the time period of 2004 through 2006. The CERTO beacons operating at 150.012, 400.032, and 1066.752 MHz will be transmitting to ground receivers located in chains to acquire TEC data for computerized ionospheric tomography (CIT). In addition, in early 2006 a five frequency receiver will be placed in low earth orbit with the United States Air Force Space Test Program (STPSAT1) satellite. This CITRIS receiver will use radio beacon transmissions from the French DORIS network of ground beacons at 401.25 and 2036.25 MHz and space-based beacons at 150, 400 and 1067 MHz to measure the earth's ionosphere. On board tracking software will lock onto Doppler shifted frequencies to determine total electron content (TEC) and scintillation parameters. The STPSAT1 will be launched along with a companion satellite (NPSAT1) which carries the CERTO radio beacon and a Langmuir probe. All of the CERTO beacons as well as the ionospheric sensors on STPSAT1 and NPSAT1 are being constructed at the Naval Research Laboratory. The data obtained using the CITRIS instrument will provide a global description of the ionosphere from orbits with inclinations ranging from 15 degrees to 70 degrees and altitudes from 375 to 800 km. The tandem operations of the CITRIS and CERTO instruments will provide the fully low-earth-orbit based occultation measurements of the ionosphere. All of the data will be available for rapid assimilation ionospheric, space-weather models.

Bernhardt, P. A.; Siefring, C. L.

2004-05-01

79

Radio wave propagation in structured ionization for satellite and radar applications  

NASA Astrophysics Data System (ADS)

This report is an extension to DNA 5304D and DNA-IR-82-02 which presented the radio propagation algorithms recommended for use by DNA to calculate the properties of scintillated signals. This report covers effects related to antennas and extends the formalism to cover two component power spectra of plasma fluctuations. In addition, an improved representation of the total electron content power spectrum is included to support space radar and similar applications. Appendix E contains SUBROUTINE PROP which implements the radio propagation models.

Wittwer, Leon A.

1993-08-01

80

Two studies of diffuse gas interactions in the Magellanic System and instrumentation for suppressing satellite signal interference in radio telescopes  

NASA Astrophysics Data System (ADS)

I present observational evidence of processes taking place in two diffuse environments of the Magellanic System important to the ultimate fate of accreting material in general and its impact on a host galaxy. Using optical and radio data, I show that initial formation of NGC 602's massive stars and subsequent chain of triggered star formation in a diffuse environment likely resulted from colliding structures of expanding remnants of supernova- or wind-driven shells. The process could take place in any gaseous interaction remnant of sufficient density as a result of large scale turbulence energized by the interaction itself. The young stars produced in an accreting remnant in this fashion would eventually contribute to the diversity of the host galaxy's stellar population. I also provide all unprecedented, direct observational glimpse into the ablation processes acting on the periphery of an accreting gaseous remnant that ultimately will determine its fate, consumption by the host's halo or reaching the disk as star-formation fuel. Using novel spatial averaging methods I found that in the interaction zone between warm MS gas and hot Halo gas, a Turbulent Mixing Layer is strongly indicated. Such an interaction can significantly moderate the ablation rate of the cloud into the Halo. Finally, I describe a Radio Frequency Interference (RFI) Suppression subsystem for insertion into radio telescope hardware systems that is capable of reconstructing and directly subtracting replicas of multiple interfering signals of Global Positioning System (GPS) and other navigation satellites, including the unique and troublesome GPS L3 signal. The subsystem provides important enhancements over prior approaches and allows handling of the complex signaling of L3. The subsystem is designed to easily "plug in" to virtually any radio telescope system and operate autonomously. Its essential function has been simulated, demonstrating its ability to identify and characterize actual interferers in sampled telescope data as well as cancellation of simulated interferers.

Nigra, Lou Michael

2012-05-01

81

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

Microsoft Academic Search

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

T. V. Omotosho; C. O. Oluwafemi

2009-01-01

82

Ionospheric profiling through radio-frequency signals recorded by the FORTÉ satellite, with comparison to the International Reference Ionosphere  

NASA Astrophysics Data System (ADS)

Electromagnetic waves originating on Earth and recorded in space allow retrieval of ionospheric parameters. Using the FastOnboard Recording of Transient Events satellite (FORTÉ, it has been shown that traps-ionospheric pulsed radio-frequency (RF) signals carry sufficient information to infer the peak electron density of the ionosphere, in addition to the total electron content along a ray path between a source and a receiver. In this paper the detailed refractive properties of the ionosphere and the biref-ringent splitting of RF waves in the Earth's magnetic field are modeled using the Appleton-Hartree equation and an electron density profile based on the International Reference Ionosphere (IRI). Applications of this model to FORTÉ data provide additional information on the vertical profile of ionospheric plasma density at the time and place of measurement. Results of the FORTÉ observations are compared with the IRI.

Moses, Ronald W.; Jacobson, Abram R.

2004-01-01

83

Radio frequency radiation beam pattern of lightning return strokes: Inferred from FORTE satellite observations  

Microsoft Academic Search

The fast propagating return stroke is expected to produce a radiation pattern differing from a dipole pattern, with a ``correction'' of (1 - v cos $\\\\theta$\\/c)-1 or the so-called F factor. The FORTE satellite measures lightning Very High Frequency (VHF) radiation at different angles from the up space and offers the first opportunity of examining the F factor. In this

Xuan-Min Shao; Abram R. Jacobson; T. Joseph Fitzgerald

2005-01-01

84

Radio frequency radiation beam pattern of lightning return strokes: Inferred from FORTE satellite observations  

Microsoft Academic Search

The fast propagating return stroke is expected to produce a radiation pattern differing from a dipole pattern, with a “correction” of (1 ? v cos $\\\\theta$\\/c)?1 or the so-called F factor. The FORTE satellite measures lightning Very High Frequency (VHF) radiation at different angles from the up space and offers the first opportunity of examining the F factor. In this

Xuan-Min Shao; Abram R. Jacobson; T. Joseph Fitzgerald

2005-01-01

85

Communications and radio determination system using two geostationary satellites. Part I: System and experiments  

NASA Astrophysics Data System (ADS)

We developed two types of hybrid terminals that can provide both satellite communication and position determination services in one system. One terminal uses the single channel per carrier (SCPC) technique and the other uses the spread spectrum (SS) technique. To evaluate the performance of the two systems, we carried out experiments in Japan and in the Pacific Ocean using two geostationary satellites, ETS-V (150 deg E) and Inmarsat (180 deg E). The ranging accuracy between the mobile terminals and the base station via the satellites was found to be about 200 m using the SCPC system and about 10 m using the SS system. The measured positioning accuracy was about 1 km in the SCPC system and about 600 m in the SS system when experiments were carried out near Japan. The experimental results show that the positioning errors were mainly caused by the orbital determination errors of the two satellites. Presented here are the configurations and features of the SCPC and SS terminals, the experimental system, and the experimental results.

Morikawa, Eihisa; Miura, Ryu; Matsumoto, Yasushi; Kimura, Kazuhiro; Arakaki, Yoshiya; Ohmori, Shingo; Wakana, Hiromitsu

1995-04-01

86

A dynamic global radio frequency noise survey as observed by the FORTE satellite at 800 km altitude  

NASA Astrophysics Data System (ADS)

Detecting transient events in noisy time series is complicated by several issues. We focus on the issue of nonstationary noise, illustrate an approach (``dynamic'' strategy) on radio frequency (RF) observations from the FORTE satellite that frequently updates the estimated background, and provide a dynamic survey of FORTE noise. The performance measure is the distribution of R2/$\\overline{R2, where R2 is the squared noise amplitude at a given frequency and $\\overline{R2 is the most recent mean squared amplitude. The definition of ``most recent'' ranges from 10 ?s to 10 s. We also vary the fraction of the update period used to compute the mean from 0.1% to 100% of the previous period. For FORTE, we define 13 geographic regions and analyze signal-free records (assumed to be representative of the noise, but discussion is provided). The best dynamic case is compared to a static strategy that uses R2/$\\overline{R2static, where $\\overline{R2static is the mean over a period that covers tens of days (tens of days is the time required for the variance of the noise to reach its maximum). It is shown that some type of dynamic strategy has better statistical sensitivity than the static strategy. This survey illustrates one way to select an ``update-the-mean'' strategy that is applicable in many settings. We also describe a multiband triggering method, which together with the update-the-mean strategy helps establish the lower limit of detection of signals of interest, for example, in the case of FORTE, in satellite-based long-baseline radio astronomy and in cosmic ray shower RF emissions.

Burr, Tom; Jacobson, Abram; Mielke, Angela

2005-12-01

87

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

Microsoft Academic Search

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

Enrica Martini; Angelo Freni; Luca Facheris; Fabrizio Cuccoli

2006-01-01

88

Giant Lobes of Centaurus A Radio Galaxy Observed with the Suzaku X-Ray Satellite  

NASA Astrophysics Data System (ADS)

We report on Suzaku observations of selected regions within the southern giant lobe of the radio galaxy Centaurus A. In our analysis we focus on distinct X-ray features detected with the X-ray Imaging Spectrometer within the range 0.5-10 keV, some of which are likely associated with fine structure of the lobe revealed by recent high-quality radio intensity and polarization maps. With the available photon statistics, we find that the spectral properties of the detected X-ray features are equally consistent with thermal emission from hot gas with temperatures kT > 1 keV, or with a power-law radiation continuum characterized by photon indices ? ~ 2.0 ± 0.5. However, the plasma parameters implied by these different models favor a synchrotron origin for the analyzed X-ray spots, indicating that a very efficient acceleration of electrons up to >~ 10 TeV energies is taking place within the giant structure of Centaurus A, albeit only in isolated and compact regions associated with extended and highly polarized radio filaments. We also present a detailed analysis of the diffuse X-ray emission filling the whole field of view of the instrument, resulting in a tentative detection of a soft excess component best fitted by a thermal model with a temperature of kT ~ 0.5 keV. The exact origin of the observed excess remains uncertain, although energetic considerations point to thermal gas filling the bulk of the volume of the lobe and mixed with the non-thermal plasma, rather than to the alternative scenario involving a condensation of the hot intergalactic medium around the edges of the expanding radio structure. If correct, this would be the first detection of the thermal content of the extended lobes of a radio galaxy in X-rays. The corresponding number density of the thermal gas in such a case is ng ~ 10-4 cm-3, while its pressure appears to be in almost exact equipartition with the volume-averaged non-thermal pressure provided by the radio-emitting electrons and the lobes' magnetic field. A prominent large-scale fluctuation of the Galactic foreground emission, resulting in excess foreground X-ray emission aligned with the lobe, cannot be ruled out. Although tentative, our findings potentially imply that the structure of the extended lobes in active galaxies is likely to be highly inhomogeneous and non-uniform, with magnetic reconnection and turbulent acceleration processes continuously converting magnetic energy to internal energy of the plasma particles, leading to possibly significant spatial and temporal variations in the plasma ? parameter around the volume-averaged equilibrium condition ? ~ 1.

Stawarz, ?.; Tanaka, Y. T.; Madejski, G.; O'Sullivan, S. P.; Cheung, C. C.; Feain, I. J.; Fukazawa, Y.; Gandhi, P.; Hardcastle, M. J.; Kataoka, J.; Ostrowski, M.; Reville, B.; Siemiginowska, A.; Simionescu, A.; Takahashi, T.; Takei, Y.; Takeuchi, Y.; Werner, N.

2013-03-01

89

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

USGS Publications Warehouse

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.

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

2005-01-01

90

Second-order ionospheric effects on satellite radio occultation observations and their impact on atmospheric studies  

NASA Astrophysics Data System (ADS)

This dissertation describes the development of first-of-a-kind mathematical models that both quantify higher-order ionospheric effects and their impact on Global Positioning System radio occultation (GPS/RO) data products. We develop new and innovative models to: a) remove the second-order ionospheric effect from Total Electron Content (TEC) estimations; b) quantify the second-order ionospheric delay in GPS/RO signal propagation using the Faraday phenomenon; c) quantify the vertical distribution of the first- and second-order ionospheric residual effects on GPS/RO data products; and d) retrieve improved atmospheric water vapour profiles. For the first time we combine GPS/RO measurements with space-based gravity missions to characterize the response of the GPS/RO-derived atmospheric parameters to the Earth's gravity anomalies. Independently, we implement these mathematical models in a new GPS/RO processing software package to investigate, for the first time, the impact of higher-order ionospheric residual effects on ionospheric and atmospheric products. We observe that under low solar activity, the second-order ionospheric residual effect introduces: a) slowly varying positive systematic biases of ˜1-3 TECU on TEC estimations as function of occultation time; b) maximum negative systematic biases of ˜0.35 N-units on atmospheric refractivity close to the Earth's surface; c) negative systematic biases of ˜0.5 K close to the Earth's surface, which decrease with altitude and above 26 km become positive, peaking at ˜2.0 K at 50 km and d) negative systematic biases of ˜0.08 mbar on the water vapour pressure. Further studies reveal that the second-order ionospheric residual effect increases non-linearly with solar variability, oscillating between +/-3 mm (at Rz12=2) and +/-15 mm (at Rz12=114), whereas its value increases with increasing latitude. The first-order ionospheric residual effect arising from the geometrical splitting of the dual-frequency GPS radiowave signals is ˜2-3 orders of magnitude smaller than the second-order ionospheric residual effect, with the potential of increasing in magnitude at high solar activity. A series of sensitivity studies show that the LEO velocity uncertainties affect the GPS/RO bending angle accuracy more than the Doppler shift uncertainties. Finally, we find that the Earth's gravity anomalies can introduce negative systematic biases on the atmospheric temperature profiles of up to ˜0.5 K close to the Earth's surface. This dissertation demonstrates the simplicity, innovation, effectiveness and importance of our proposed mathematical models on the future of GPS/RO atmospheric remote sensing.

Vergados, Panagiotis

91

Radio frequency radiation beam pattern of lightning return strokes: Inferred from FORTE satellite observations  

NASA Astrophysics Data System (ADS)

The fast propagating return stroke is expected to produce a radiation pattern differing from a dipole pattern, with a "correction" of (1 - v cos ?/c)-1 or the so-called F factor. The FORTE satellite measures lightning Very High Frequency (VHF) radiation at different angles from the up space and offers the first opportunity of examining the F factor. In this report, we studied a group of FORTE-detected lightning events that were also observed by the National Lightning Detection Network (NLDN). NLDN provided the discharges' geolocations and helped to identify the discharge types. During the summers of 1998 and 1999, 25,721 coincident events were found. Among these, 2092 were found to be narrow (<100 ns), VHF-intense and highly polarized bursts and were found to be associated with the beginning of return strokes. Through careful statistical analysis regarding the distributions of the event occurrence, we found that the overall ensemble of events can be considered to have an isotropic pattern in the upper half-space. The subset of the narrow bursts displays a beam pattern that agrees with the F factor at a propagating speed of v = 0.75c. The latter is inferred by comparing FORTE observations to a free-space transmission line (TL) model. The analysis shows that the ground does not affect the narrow-burst beam pattern observed from the upper half-space; the source for the narrow burst needs to be a few tens of meters above the surface of the Earth and is apparently associated with the junction point of the attachment process. The physical size of the corresponding discharge is estimated to be less than 20 m. The analysis also suggests that a single upward current is responsible for the observations, rather than a bidirectional current as suggested by others for the attachment process. Similarly, the traveling current source (TCS) model that consists of a simultaneous downward current is found less suitable for the initiation of return strokes.

Shao, Xuan-Min; Jacobson, Abram R.; Fitzgerald, T. Joseph

2005-12-01

92

User applications unique to mobile satellites  

NASA Astrophysics Data System (ADS)

As AMSC enters the market with its mobile satellite services, it faces a sophisticated user group that has already experimented with a wide range of communications services, including cellular radio and Ku-band satellite messaging. AMSC's challenge is to define applications unique to the capabilities of its dedicated L band satellite and consistent with the provisions outlined in its FCC license. Through a carefully researched approach to its three main markets (aeronautical, land mobile, and maritime) AMSC is discovering a wellspring of interest in corporate and general aviation, trucking companies, pipeline monitoring and control companies, maritime management firms, telecommunications companies, and government agencies. A general overview is provided of AMSC's FCC license and corporate history, and the specific applications unique to each user group is discussed.

Castiel, David

93

Powerful solar radio bursts as a global and free tool for testing satellite broadband radio systems, including GPS–GLONASS–GALILEO  

Microsoft Academic Search

We investigated failures in the global positioning system (GPS) performance produced by solar radio bursts with unprecedented radio flux density during the X6.5 and X3.4 solar flares on 6 and 13 December 2006, respectively. The effect of these events on GPS was compared to that of the X17.2 solar flare of 28 October 2003. Significant experimental evidence was found that

E. L. Afraimovich; V. V. Demyanov; A. B. Ishin; G. Ya. Smolkov

2008-01-01

94

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)

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.

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

2012-09-01

95

47 CFR 25.214 - Technical requirements for space stations in the satellite digital audio radio service.  

Code of Federal Regulations, 2010 CFR

...B) 2332.5-2340.0 MHz for satellite DARS. (b) Each system authorized...outlined in § 25.144(b). The failure to meet any of the milestones contained...assignments will be made for each satellite DARS system as follows:...

2009-10-01

96

47 CFR 25.214 - Technical requirements for space stations in the satellite digital audio radio service and...  

Code of Federal Regulations, 2010 CFR

...B) 2332.5-2340.0 MHz for satellite DARS. (b) Each system authorized...outlined in § 25.144(b). The failure to meet any of the milestones contained...assignments will be made for each satellite DARS system as follows:...

2010-10-01

97

47 CFR 25.214 - Technical requirements for space stations in the satellite digital audio radio service and...  

Code of Federal Regulations, 2011 CFR

...MHz and 2332.5-2345.0 MHz; (3) Satellite DARS licensees may reduce their assigned bandwidth occupancy to provide telemetry beacons in their exclusive frequency assignments; (4) Each licensee may employ cross polarization within its...

2011-10-01

98

47 CFR 25.214 - Technical requirements for space stations in the satellite digital audio radio service and...  

Code of Federal Regulations, 2012 CFR

...MHz and 2332.5-2345.0 MHz; (3) Satellite DARS licensees may reduce their assigned bandwidth occupancy to provide telemetry beacons in their exclusive frequency assignments; (4) Each licensee may employ cross polarization within its...

2012-10-01

99

Satellite congestion  

NASA Astrophysics Data System (ADS)

At last count, there were more than 160 satellites in geostationary orbits, circling the earth at an altitude of 37,000 km, and according to a research review published recently by the Rand Corporation, that's already too crowded. The risk of physical collisions among satellites is small, say authors Alvin L. Hiebert and William Sollfrey, but there is an emerging problem with what they call “spectral and orbital congestion,” the result of too many satellites and ground stations sending out too many electromagnetic signals that can interfere with one another.The report comes at a time when the Federal Communications Commission is planning to reduce the spacing between satellites along the U.S. segment of the orbital arc so that 37 additional satellites can be squeezed into the high orbit favored for telecommunications. “As more satellites are launched and others are shifted to avoid collisions, interference problems will get more complicated,” say the authors of the report.

100

RESULTS OF RADIO HOLOGRAPHIC ANALYSIS OF GPS OCCULTATION SIGNALS REGISTERED DURING CHAMP AND GPS\\/MET SMALL SATELLITES MISSIONS  

Microsoft Academic Search

In this contribution new applications regarding the GPS radio occultation (RO) method in geophysical researches are presented: (1) measuring the vertical gradients of the refractivity in the atmosphere and electron density in the lower ionosphere, (2) investigation of the internal wave's activity in the atmosphere, (3) study of the ionospheric disturbance on a global scale. The new directions may be

J. Wickert; Y. A. Liou; A. A. Pavelyev; T. Schmidt; S. S. Matyugov

101

The role of the atmosphere in satellite geodesy, radio astronomy and other applications of trans-atmospheric propagation of radio waves  

NASA Astrophysics Data System (ADS)

The influence of the atmosphere on radio waves relevant to technological applications is investigated theoretically, and the associated errors are classified and defined. Range errors are defined as the length of the phase path minus the geometric distance, and range errors are divided into those related to the troposphere and those related to the ionosphere. Ground-path error and group delay are also mentioned as important errors which can influence the angle of arrival and direct ranging. Ionospheric range errors are defined in terms of first-order and higher-order errors including the second-order refraction error, and the pulse-travel-time delay is mentioned. The parameters required to estimate ionospheric errors include slant electron content, and mean ionospheric height, and the second-order errors require knowledge of the vertical electron content, the equivalent slant thickness, the height of the F-layer peak, and the shape factor.

Leitinger, R.

102

Analysis of Global Positioning System (GPS) radio occultation measurement errors based on Satellite de Aplicaciones Cientificas-C (SAC-C) GPS radio occultation data recorded in open-loop and phase-locked-loop mode  

NASA Astrophysics Data System (ADS)

The error characteristics of Global Positioning System (GPS) radio occultation (RO) measurement errors are studied based on Satellite de Aplicaciones Cientificas-C (SAC-C) GPS radio occultation data tracked in both open-loop (OL) and phase-locked-loop (PLL) mode. The error characteristics are derived by applying dynamical error estimation, i.e., without using any external data. The computed error profiles show that the mean measurement errors are the smallest in the height range between about 5-7 km and 20-25 km, about 0.2-1% for bending angles and 0.1-0.2% for refractivity at all latitudes. The largest measurement errors are found in the lower troposphere, where the mean bending angle measurement errors are within the range from 1 to 6%, whereas the mean refractivity measurement errors are within the range from 0.2% to 1%. From the error distributions, it is found that the occultation-to-occultation variability of the measurement errors generally spans one order of magnitude. The bending angle error correlation length is about 1 km and 100 m, at high and low altitudes, respectively, corresponding approximately to the cutoff frequency of the applied noise filters. The widths of the refractivity error autocorrelation functions are notably broader. The variability and the magnitude of the OL measurement errors are larger than for the PLL measurement errors. This is mainly attributed to the ability of OL tracking to track RO signals under atmospheric conditions for which PLL tracking fails.

Lohmann, Martin S.

2007-05-01

103

Low Earth orbit communications satellite  

NASA Astrophysics Data System (ADS)

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.

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

104

Corporate Capitalism, Corporate Crime  

Microsoft Academic Search

This article considers the structural relationships between corporate crime and American corporate capitalism. Large corporations are assumed to pursue profit, growth, and market share expansion subject to constraints imposed by markets and the state. State or legal regulation of corporate behavior is in turn assumed to be constrained by the need to promote capital accumulation and to satisfy diverse economic

Harold C. Barnett

1981-01-01

105

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

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.

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

2013-01-01

106

Analysis of Radio Frequency Interference to the Deep Space Network From a Constellation of Low Earth Orbit Satellites  

Microsoft Academic Search

Recently, many low Earth orbit (LEO) satellite constellations have been proposed as an infrastructure for data, voice, and wireless communications. Among these is Motorola's M-Star system, which uses a downlink frequency band at 37.5 to 40.5 GHz. This band overlaps the band at 37.5 to 38.0 GHz that is allocated to space research service (space to Earth). Thus, interference from

H. Kuo

1998-01-01

107

Influence Nonuniformity of the Atmospheric Water Vapor Field on the Phase Measurements of Radio Signals from Global Navigation Satellite Systems  

NASA Astrophysics Data System (ADS)

We present the experimental results for the horizontal gradients of integrated content of atmospheric water vapor, which are retrieved from the phase measurements of signals in the receiver network of the global navigation satellite systems in 2011 in the Republic of Tatarstan. The seasonal gradient variation is found. The meridional gradient usually shows a decrease in integrated water vapor with increasing latitude, and its monthly mean values are equal to -1.8 mm and 0.1 mm of precipitable water per 100 km in August and December, respectively. The zonal monthly average gradient is somewhat smaller in magnitude than the meridional one and is equal 0.1 mm and -0.8 mm per 100 km in March/June and May/October, respectively. Instantaneous values of the gradients can by an order of magnitude higher than the monthly mean values. Contribution from the gradient of integral water vapor to the phase-measurement difference between two antennas spaced 30 km apart is shown to attain its maximum of 141.5 mm in August for the zenith angle 80°. Errors in determining the mutual location of the ground-based antennas of global navigation satellite systems due to the water vapor gradients can reach 66 mm and 16.9 mm in August and February, respectively.

Kalinnikov, V. V.; Khutorova, O. G.; Teptin, G. M.

2013-07-01

108

First observations of large-scale wave structure and equatorial spread F using CERTO radio beacon on the C/NOFS satellite  

NASA Astrophysics Data System (ADS)

Equatorial spread F (ESF) is a generic name, which refers to the presence of a wide spectrum of field-aligned irregularities in the equatorial nighttime F-region that can extend over nearly seven orders of magnitude. Recently, a large-scale wave structure (LSWS) in the F-layer electron density is identified as a reliable precursor to ESF. The LSWS can be identified as a quasi-periodic modulation in the altitude of isoelectron density contours in the bottomside F-region, superimposed on a mean slope that increases in altitude from west to east. First observations of large-scale wave structure (LSWS) and the subsequent development of equatorial spread F (ESF), using total electron content (TEC) derived from the ground based reception of Coherent Electromagnetic Radio Tomography (CETRO) radio beacon signals on board the C/NOFS (Communications/Navigation Outage Forecasting System) satellite will be presented. For this study the TEC observations from Bac Lieu, Vietnam (9.2°N, 105.6°E geographic, 1.7°N magnetic dip latitude), Phukhet (7.8°N, 98.38°E, 0.4°S dip lat) and Kototabang, Indonesia (0.20°S, 100.32°E, 10.36°S dip lat) are analyzed along with ionosonde observations from Bac Lieu, Chumphon (10.7°N, 99.4°E, 3.3° dip lat) and 30.8 MHz VHF radar observations from Kototabang. It should also be mentioned here that LSWS is not easily detectable with overhead measurements using a sensor at a fixed location, at least not during its early growth phase, mainly because initially it grows in amplitude without significant zonal drift. The results indicate (1) LSWS appears to play a more important role in the development of ESF than the post-sunset rise (PSSR) of the F-layer, and (2) LSWS can appear well before E-region sunset. Other findings, that LSWS does not have significant zonal drift in the initial stages of growth, and can have zonal wavelengths of several hundred kilometers, corroborate earlier reports.

Thampi, S.; Yamamoto, M.; Tsunoda, R. T.; Otsuka, Y.; Tsugawa, T.; Uemoto, J.; Ishii, M.

2009-12-01

109

Radio-relay communication  

Microsoft Academic Search

In this text book, the principles of designing conventional, tropospheric, and satellite radio-relay links are discussed. Particular attention is given to frequency modulated communication lines and lines with frequency separated channels. The principles of designing radio-relay equipments are reviewed.

V. V. Markov

1979-01-01

110

The GNSS polarimetric radio-occultation technique to sense precipitation events: a new concept to be tested aboard PAZ Low Earth Satellite  

NASA Astrophysics Data System (ADS)

The Radio Occultation and Heavy Precipitation (ROHP) experiment, to be conducted aboard the Spanish PAZ satellite, consists of a radio occultation (RO) mission provided with dual-polarization capabilities. The research with polarimetric RO data has the goal of assessing the capabilities and limitations of this technique to infer profiles of heavy precipitation. The technique aims to provide vertical profiles of precipitation simultaneously to the vertical profiles of thermodynamic parameters (standard RO products) perfectly collocated both in space and time. If successful, the polarimetric RO will represent the first technique able to provide these complementary information on precipitation. This is a relevant input for studies on heavy and violent rainfall events, which being poorly represented by the current-generation of Numerical Weather Prediction and General Circulation Models appear to be difficult to forecast on all time-scales. The Low Earth Orbiter hosting this experiment, to be launched in 2013, will orbit at 500 km altitude in a near-Polar orbit. The Radio Occulation payload includes a RO GNSS receiver and a dual polarization (H/V) limb oriented antenna to capture the signals of setting GNSS transmitters. NOAA and UCAR participate in the ground-segment of the radiometric experiment to enable near-real time dissemination of the level-1 standard RO products. The space-based GNSS RO technique scans the atmosphere vertically at fine resolution (close to 300 meter in the troposphere) by precisely measure the delay between a GNSS transmitter and a GNSS receiver aboard a Low Earth Orbiter, when the former is setting below or rising above the Earth limb. The standard, thermodynamical, products are extracted from the excess delay induced by the atmosphere at different layers. This presentation will not focus on this well-established application, but a novel concept using polarimetry to also retrieve rain information. The precipitation-measurement principle is based on the asymmetry between the vertical and horizontal axis of the rain droplets, especially when intense rates of precipitation occur. As a first approximation, the RO signals propagate across the precipitation-volume tangentially, that is, along the local horizontal axis of the droplets. Forward scattering models have been implemented to quantify the sensitivity of L-band signals to different rain rates and precipitation extension being crossed by the signals. The observable considered so far is the polarimetric phase shift: difference between the phase delay suffered by the H- and V-polarizations. Real RO events have been collocated with TRMM precipitation data. The path traveled by the RO signal under a given altitude has been projected on the TRMM grid of observations, to obtain a profile of the precipitation being crossed by the RO link at a given moment of the occultation event. This mechanism has been used to feed the propagation models and thus estimate the polarimetric phase shift that each precipitation event would have induced into the occultation observation. This simulation exercise permits to determine the detectability thresholds and the expected statistics of such collocated events. Methodology and results will be presented.

Tomás, Sergio; Oliveras, Santi; Cardellach, Estel; Rius, Antonio

2013-04-01

111

The Use of Satellites by Schools and Colleges, Part 1.  

ERIC Educational Resources Information Center

Provides information about and suggestions for using orbital satellite-carrying amateur radio (OSCAR) and National Oceanic and Atmospheric Administration (NOAA) satellites for instructional purposes. (JN)

Duff, D. A.

1981-01-01

112

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

NASA Astrophysics Data System (ADS)

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.

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

113

Improvements Made, Some Still Needed in Management of Radio Free Europe/Radio Liberty.  

National Technical Information Service (NTIS)

GAO recommended in 1976 the consolidation of two separate organizations, Radio Free Europe and Radio Liberty. Since then the parent corporations have merged, a number of dual operations were combined, and other recommendations for improving the economy an...

1981-01-01

114

DBS Radio: Deathstar or Dud? Info. Packets No. 24.  

ERIC Educational Resources Information Center

|The Federal Communications Commission (FCC) has been progressing over the past 5 years toward the institution of Direct Broadcast Satellite Radio (DBS-R) which would institute a new type of radio service. The FCC refers to the service as Satellite DARS (Digital Audio Radio Service), and it would provide reliable, high-fidelity satellite-delivered…

Pizzi, Skip

115

DBS Radio: Deathstar or Dud? Info. Packets No. 24.  

ERIC Educational Resources Information Center

The Federal Communications Commission (FCC) has been progressing over the past 5 years toward the institution of Direct Broadcast Satellite Radio (DBS-R) which would institute a new type of radio service. The FCC refers to the service as Satellite DARS (Digital Audio Radio Service), and it would provide reliable, high-fidelity satellite-delivered…

Pizzi, Skip

116

Radio imaging of layers and investigation of the internal atmospheric waves by use of high-stable signals of navigational satellites  

Microsoft Academic Search

An essential connection between the eikonal acceleration and intensity of radio waves has been established under assumption of local spherical symmetry. This connection is similar to the well known classical dynamics equation. Application of this relationship to analysis of experi-mental radio occultation data obtained during CHAMP and FORMOSAT-3 missions revealed that the second derivative of the eikonal with respect to

Alexander Pavelyev; Yuei An Liou; Vladimir Gubenko; Kefei Zhang; Yuriy Kuleshov

2010-01-01

117

Radio Galaxies.  

ERIC Educational Resources Information Center

|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)|

Downes, Ann

1986-01-01

118

Corporate Privacy and Information Technology: the Case of RFID  

Microsoft Academic Search

Like every new information technology, Radio Frequency identification (RFID) has security issues that could jeopardize corporate privacy. This paper explores the concept of corporate privacy by looking at both the development of the philosophical concept of (individual) privacy and the legal framework that governs corporate privacy. Further, it discusses the general requirements of corporate privacy: protecting economically valuable information and

Sascha Vitzthum

119

The strategic corporate intelligence and transformational marketing model  

Microsoft Academic Search

Reference to the strategic marketing and corporate intelligence interface is made explicit in this paper, and various contributions to the field of competitive intelligence are highlighted. A conceptual model, known as the strategic corporate intelligence and transformational marketing (SATELLITE) model is outlined, and can be used by corporate intelligence staff to provide better marketing intelligence. The SATELLITE model provides a

Peter R. J. Trim

2004-01-01

120

77 FR 2242 - Radio Broadcasting Services; Ehrenberg, First Mesa, Kachina Village, Wickenburg, and Williams, AZ...  

Federal Register 2010, 2011, 2012, 2013

...RM-11519; DA 11- 2059] Radio Broadcasting Services; Ehrenberg...community's fourth local transmission service, because no comments...proposals filed by Rocket Radio, Inc. (RM-11517) and Univision Radio License Corporation...

2012-01-17

121

Calibration Technology for Meteorological Satellites.  

National Technical Information Service (NTIS)

The focus of this study is the meteorological satellite and the data derived therefrom. The assurance of data quality acquired by sensors which are located hundreds of miles away, and accessible only after radio transmission and various other electronic o...

L. E. Williamson

1977-01-01

122

'RARC '83' - International planning for broadcasting satellites at 12 GHz  

NASA Astrophysics Data System (ADS)

It is pointed out that 14 corporations have applied to the Federal Communications Commission (FCC) to operate broadcasting satellite systems in the U.S. The applications are concerned with operations in the 12 GHz band. In connection with these applications, the FCC is placed into a difficult position, related partly to uncertainties regarding the portion of the limited orbit spectrum resource which will be available to the U.S. In June of 1983, the Regional Administrative Radio Conference (RARC '83) will be convened for the planning of broadcasting satellites for Region 2, which consists basically of the Americas and the Caribbean. One type of planning favored by many countries would involve very detailed specification or orbit spectrum 'allotments' to the various administrations. The consequences of such an approach are critically evaluated. Attention is given to the geostationary orbit-spectrum, U.S. preparatory efforts, and a scenario to minimize a-priori planning.

Hupe, H. H.

123

The ionosphere as a focusing lens - A case study involving simultaneous type III solar radio storm measurements from the ISIS 1 and 2 and ISEE 3 satellites  

Microsoft Academic Search

The possibility of using terrestrial ionospheric focusing to improve the directivity of electric dipoles on space missions has been investigated by comparing simultaneous observations of a solar radio storm by the ISIS 1 and ISIS 2 spacecraft, in near earth orbit, and the ISEE 3 spacecraft located beyond the magnetosphere. To this end, a three-dimensional ray tracing in a spherically

H. G. James; R. F. Benson; J. Fainberg; R. G. Stone

1990-01-01

124

Corporate Crime  

Microsoft Academic Search

Corporate criminal liability is a relatively new development in American law, although it has been expanding rapidly. We argue that there is no need for corporate criminal liability in a legal system with appropriate civil remedies and that corporate criminal liability in practice produces serious problems of overdeterrence. Copyright 1996 by the University of Chicago.

Daniel R. Fischel; Alan O. Sykes

1996-01-01

125

Corporate Environmental Social Responsibility: Corporate \\  

Microsoft Academic Search

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

Hope M. Babcock

2010-01-01

126

Multiple Scientific Uses of Radio Occultation  

Microsoft Academic Search

Global Navigation Satellite System Radio Occultation Workshop; Pasadena, California, 7-9 April 2009; There is a clear need for observing systems that characterize decadal-scale changes of the climate system. A National Research Council (NRC) report, ``Earth science and applications from space'' (2007); recommends the radio occultation (RO) technique to monitor climate change. Radio occultation establishes a global climate benchmark by measuring

Anthony J. Mannucci; Christian Rocken

2009-01-01

127

Using millimeter radio waves to probe the earth's atmosphere  

Microsoft Academic Search

We analyze the unique features involved in employing millimeter radio waves to investigate and monitor the earth's atmosphere by means of radio transmissions involving the use of two satellites. We discuss the absorption of radio waves in the atmosphere along the path of the two satellites, depending on the wavelength and the time of year. Signal attenuation is analyzed in

S. D. Eliseev; O. I. Yakovlev

1989-01-01

128

NAVY EDUCATION THROUGH AMATEUR SATELLITE DEVELOPMENT  

Microsoft Academic Search

The Naval Postgraduate School (NPS) is developing a small satellite for digital store-and-forward communication using spread spectrum techniques. NPS is looking toward the amateur radio community in an effort to utilize cost- effective engineering and proven means of radio message relay. This cooperative initiative between NPS and the amateur radio community provides numerous benefits for the education of NPS officer

J. A. Horning

129

Astronomical principles of satellite positioning  

Microsoft Academic Search

The Global Navigation Satellite Systems (GNSS) dominate the positioning technologies at the beginning of this millennium. The new concept, already common in all users' segments, refer to those radio-navigation systems providing highly precise time and position information, continuously and globally, disregarding the weather status. In the present paper, a comparison between the principles of celestial navigation and satellite navigation is

Adrian Dragusan; Sergiu Lupu; Stelian Cojocaru

2008-01-01

130

Mobile satellite communications for consumers  

NASA Astrophysics Data System (ADS)

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

Noreen, Gary K.

1991-11-01

131

Model for the prediction of the differential rain attenuation between a terrestrial line-of-sight radio relay system and a low-angle satellite path based on the two-dimensional lognormal distribution  

NASA Astrophysics Data System (ADS)

The main propagation effect on interference of a terrestrial line-of-sight radio relay system from a low-angle satellite path is the differential rain attenuation. In the present paper, a predictive method for the differential rain attenuation statistics is proposed which is based on a modified model convective raincell structure by taking into account the conventional limits of the raincell size. The assumption that the point rainfall statistics follows a lognormal form is also adopted. The results of the predictive procedure are applied to a particular problem of terrestrial line-of-sight system interference from a low-angle broadcasting satellite service in the 22.5-23 GHz band. The sensitivity of the various parameters affecting the differential attenuation is also examined. As a general remark, the conditional differential rain probability is found to be significantly dependent upon the rainfall characteristics of the climatic zone and the parameters of the spatial rainfall structure. Finally, a comparison of the present predictive procedure with a semiempirical developed model is treated and gives a quite reasonable agreement.

Kanellopoulos, J. D.; Kossidas, C.

1994-07-01

132

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)

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.

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

2011-11-01

133

GRAS SAF RADIO OCCULTATION PROCESSING CENTER  

Microsoft Academic Search

The GRAS SAF is part of EUMETSATs network of Satellite Application Facilities (SAFs) under the EUMETSAT Polar System (EPS). The objective of the GRAS SAF is to deliver operational radio occultation products from the GRAS occultation instruments (Global Navigation Satellite System Receiver for Atmospheric Sounding) onboard the three Metop satellites. The host institute is the Danish Meteorological Institute (DMI) and

K. B. Lauritsen; H. Gleisner; A. Loescher; F. Rubek; M. B. Sørensen

2005-01-01

134

Characteristics of small-scale ionospheric irregularities as deduced from scintillation observations of radio signals from satellites ETS-2 and Polar Bear 4 at Irkutsk  

NASA Astrophysics Data System (ADS)

This paper presents some new results on the small-scale inhomogeneous ionospheric structure obtained at a facility for spaced-antenna reception of transionospheric signals from ETS-2 and Polar Bear 4 near Irkutsk (Eastern Siberia, 52 deg N, 104 deg E). A technique based on transferring time spectra of scintillations to spatial spectra using measured horizontal irregularity drift velocities is used to obtain an estimate of the mean spatial spectrum of midlatitude scintillations. Two different methods were used to determine the inclination index of the scintillation spectrum, which was found to be equal to -2, in agreement with the value recently predicted for small-scale F region irregularities generated through mapping of small-scale, turbulent electric fields from the E region to the F region. Drift velocities of the diffraction pattern, and also the altitudes at which ionospheric irregularities are located, agree well with results obtained by other authors for midlatitudes. Using simultaneous measurements for a geostationary satellite and an orbiting satellite, the supposition about the existence of the southern boundary of the scintillation region has been confirmed. Finally, analysis of quasi-periodic (QP) scintillations and simultaneously determined diffraction pattern velocities is used to show that the height of isolated irregularities giving rise to QP scintillations corresponds to the maximum of the ionospheric F2 region.

Afraimovich, E. L.; Zherebtsov, G. A.; Zvezdin, V. N.; Franke, S. J.

1994-07-01

135

76 FR 14297 - The Establishment of Policies and Service Rules for the Broadcasting-Satellite Service  

Federal Register 2010, 2011, 2012, 2013

...to access the market in the United...Andrea Kelly, Satellite Division, International...the U.S. market from a Canadian...subsidiaries, Skynet Satellite Corporation...24 GHz BSS satellite operators seeking access to the market in the...

2011-03-16

136

Corporal punishment.  

PubMed

Pediatricians differ on the optimal ways to discipline children. The major controversy surrounds the use of corporal punishment. In an effort to resolve this controversy, the American Academy of Pediatrics (AAP) cosponsored a conference entitled "The Short and Long-Term Consequences of Corporal Punishment" in February 1996. This article reviews scientific literature on corporal punishment and summarizes the proceedings from the conference. The authors conclude that, although the research data are inadequate to resolve the controversy, there are areas of consensus. Practitioners should assess the spanking practices of the parent they see and counsel parents to avoid those that are, by AAP consensus, dangerous, ineffective, or abusive. PMID:9568019

Bauman, L J; Friedman, S B

1998-04-01

137

Investigation of a rift zone in the western Fimbulisen by means of airborne radio echo sounding, satellite imagery, and ice flow modelling  

NASA Astrophysics Data System (ADS)

The Fimbulisen, an ice shelf located roughly between 3°W-8°E at the coast of Dronning Maud Land, East Antarctica, consists of the fast flowing extension of Jutulstraumen and slower moving parts west and east of it. The largely rifted western part of the Fimbulisen is the subject of this study, which combines observations and modelling. Airborne radio echo sounding performed by the Alfred Wegener Institute between 1996 and 2008 with a frequency of 150 MHz and pulse length of 60 ns, respectively 600 ns, is analysed in order to study the internal structure of the ice in parts of the rift zone and to estimate the ice thickness in this area precisely. High-resolution radar imagery acquired by the TerraSAR-X in 2008 and 2009 is used to evaluate principal deformation axis at characteristic locations, to detect crack modes as well as to classify zones of similar structural characteristics. These zones were incorporated in a 2D diagnostic ice flow model as sub-domains with variable stress enhancement factor and thus treated as zones of different damage related stiffness. The temperature-dependent stiffness is calculated by applying the solution of a validated 3D temperature model of the ice shelf and thus the simulations focus on the softening effect caused by cracks. Extensive parameter studies show the effect of the stress enhancement factor on the principal deformation rates and axis. Comparison with the estimated deformation pattern aims to confine the softening effect for each zone separately.

Humbert, Angelika; Steinhage, Daniel

2010-05-01

138

Healthy satellites provide quality service  

NASA Astrophysics Data System (ADS)

The procedures used by Telesat Canada to ensure the performance of Anik satellites is described. At the Satellite Telemetry, Tracking and Command station, each Anik satellite has its own dedicated antenna. Telemetered information from the satellites is received, processed and forwarded to the Satellite Control Center. There the satellite controllers issue all commands to the satellites, and continually monitor the telemetered data. These data, describing the state of health of the satellites, are then analyzed by engineering specialists. The satellites are held in their precise orbital positions by means of specially developed software. The Anik C and D satellites employ travelling wave tube amplifiers (TWTAs) in the transpounder channels. The TWTA saturated flux density (SFD) and equivalent isotropic radiated power (EIRP) are regularly measured and their trends scrutinized. This ensures that customers receive the radio frequency power needed for high-quality service. The satellite electrical power is supplied by the solar cell array and batteries. Power system performance is evaluated regularly to ensure that power is available to operate the required number of TWTAs. In addition to rain-fades, short service interruptions can be caused by high voltage trip-offs of TWTAs, and by electrostatic discharge related anomalies. To minimize these interruptions, Telesat ensures that the satellite controllers are fully trained and prepared for any eventuality, and the relevant operational procedures are continually refined. A fully trained staff of satellite controllers keep interruptions caused by high voltage trip-offs of TWTAs and by electrostatic discharge to a minimum.

Margittai, Paul

139

TV via satellite from AT&T  

NASA Astrophysics Data System (ADS)

AT&T's Satellite Television Service, which relays TV feeds by means of the Comstar domestic communications satellite system, is discussed. Advantages include the ability to provide multiple feeds of program and advertising material simultaneously to affiliates, which can help accommodate the trend toward greater program diversity, and the ability to distribute one signal to many points, making their use economically attractive. A proposed radio service from AT&T is also discussed, which could provide radio broadcasters and programmers with a high-quality, versatile means of transmitting radio programs via satellite.

Kiely, J.

1982-04-01

140

A speech synthesizer for a highway advisory information radio system  

Microsoft Academic Search

This paper describes a highway advisory information radio system (highway radio system) and a speech synthesizer that is used in it. The Japan Highway Public Corporation has been developing highway radio systems which collect traffic information and automatically broadcast it using a speech synthesizer in order to improve safety and convenience of driving. In such systems, detailed and appropriate information,

Akio Yokota; Yasushi Ishikawa; S. Yamane

1994-01-01

141

47 CFR 80.1185 - Supplemental eligibility for mobile-satellite stations.  

Code of Federal Regulations, 2010 CFR

...eligibility for mobile-satellite stations. 80... FEDERAL COMMUNICATIONS COMMISSION...SERVICES STATIONS IN THE MARITIME...Installations Mobile-Satellite...maritime mobile-satellite... (a) A station license for...nonprofit radio communication...

2010-10-01

142

47 CFR 80.1185 - Supplemental eligibility for mobile-satellite stations.  

Code of Federal Regulations, 2010 CFR

...eligibility for mobile-satellite stations. 80... FEDERAL COMMUNICATIONS COMMISSION...SERVICES STATIONS IN THE MARITIME...Installations Mobile-Satellite...maritime mobile-satellite... (a) A station license for...nonprofit radio communication...

2009-10-01

143

47 CFR 80.1185 - Supplemental eligibility for mobile-satellite stations.  

Code of Federal Regulations, 2011 CFR

...Supplemental eligibility for mobile-satellite stations. 80.1185 Section 80...Voluntary Radio Installations Mobile-Satellite Stations § 80.1185 Supplemental eligibility for mobile-satellite stations. Stations in the...

2011-10-01

144

47 CFR 80.1185 - Supplemental eligibility for mobile-satellite stations.  

Code of Federal Regulations, 2012 CFR

...Supplemental eligibility for mobile-satellite stations. 80.1185 Section 80...Voluntary Radio Installations Mobile-Satellite Stations § 80.1185 Supplemental eligibility for mobile-satellite stations. Stations in the...

2012-10-01

145

Operating model satellite for space education  

NASA Astrophysics Data System (ADS)

Satellite technology is still a deep mystery for most of the people in the world, because there is little access to satellites, even through the media. A process has been devised to build a low-cost educational cardboard model of a communication satellite, using light beams to simulate the radio links. The construction of the model follows closely the construction process of a real satellite, and can help to understand the general technology, while producing an attractive "toy."

Pignolet, Guy G.

146

Satellite communications today  

NASA Astrophysics Data System (ADS)

Satellites have opened up prospects for the development of communications, television, and radio broadcasting systems. The area of applications of these systems were expanded and possibilities have appeared. The history of the development of commumications systems is discussed along with its advantages and shortcomings. Development prospects are examined. The implementation of the developments will make it possible to raise the technical level of satellite communications systems and to increase the number of services which can be offered to the people by the communications industry, as well as to improve the quality of an individual services for the country, especially its eastern region.

Zubarev, Yu. B.

1987-02-01

147

Satellite navigation method based on user's clock synchronization  

Microsoft Academic Search

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

Koji Yamawaki

1991-01-01

148

Small satellite launch system  

NASA Astrophysics Data System (ADS)

The World Administrative Radio Conference (WARC 92) delegates agreed to worldwide frequency allocation changes that will introduce new space communications services through low earth orbit (LEO) satellite systems. Iridium, Odyssey and Orbcomm are major proposals for these services, and each proposal is to launch 77, 12 and 18 small communications satellites. In this way, the new era of small satellites is going to be initiated. The anticipation of the expansion of the small satellite launch market, new cost-effective and flexible launch systems have been developed. In 1990 Orbital Science Corp. successfully completed the maiden flight of the PEGASUS winged launch vehicle and now has been developing the new TAURUS launch vehicle. Arianespace successfully completed two ASAP (Arian Structure for Auxiliary Payloads) missions, and its new small satellites deployment system is in the process of development. McDonnel Douglas is thinking of Delta II launch vehicle applications for small satellites. This trend is seen to continue through the 1990s. This paper describes the trend of the small satellite launch market and the availability of a planned launch system in Japan.

Kochiyama, Jiro

149

Radio Control.  

National Technical Information Service (NTIS)

Radio control of the motions of aerospace vehicles of various types and purposes (missiles, spacecraft, aircraft) is examined. Chief attention is focused on the principles and methods of radio control. Current methods of analysis and synthesis of the corr...

L. S. Gutkin V. B. Pestryakov V. N. Tipugin

1971-01-01

150

Broadcast satellite service: The international dimension  

NASA Astrophysics Data System (ADS)

The dawn of the 1990's has witnessed the birth of a new satellite service - satellite sound broadcasting. This new service is characterized by digital transmission at data rates up to 256 kb/s from satellites in geostationary orbit to small, low-cost, mobile and portable receivers. The satellite sound broadcasting service is a logical step beyond navigation satellite service, such as that provided by the GPS Navstar system. The mass market appeal of satellite sound broadcasting in the area of lightsat technology and low-cost digital radios has greatly facilitated the financing of this type of space service.

Samara, Noah

1991-09-01

151

Radio Days.  

ERIC Educational Resources Information Center

|Thousands of today's high school students run FM radio stations at school, carrying on a tradition that began 50 years ago. Radio helps students learn to work with others and develop a strong sense of responsibility. A sidebar gives advice on starting a high school radio station. (MLF)|

Sanderson, Neil

1998-01-01

152

78 FR 9915 - Radio Broadcasting Services; AM or FM Proposals To Change the Community of License  

Federal Register 2010, 2011, 2012, 2013

...AL; AZALEA RADIO CORPORATION, Station NEW, Facility ID 183371, BMPH- 20121206ACO, From ROUNDUP, MT, To LEWISTOWN HEIGHTS, MT; COLONIAL RADIO GROUP, INC. Station WBYB, Facility ID 4586, BPH-20130104ACK, From KANE, PA, To ELDRED,...

2013-02-12

153

How Far Away Are the Satellites?  

NSDL National Science Digital Library

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.

Glasscoe, Maggi

2010-06-10

154

Corporate Brand Cube: Building Strong Corporate Brands  

Microsoft Academic Search

When Chinese companies start shifting their focus from domestic markets to global markets, corporate branding is an unavoidable issue. We propose a model, corporate brand cube model (CBCM), to help Chinese companies in their corporate branding. The CBCM is an extension of the current corporate branding frame. It redefines the concept of the corporate brand as a relationship between a

An Shi; Gao Liang; Wang Jian

2006-01-01

155

Olin Corporation  

Microsoft Academic Search

Olin Corporation is evaluating the financial structure for a proposed joint venture in Brazil. The head of Olin's international operations needs to recommend a financing plan as well as the project to the directors. The case is a vehicle for analyzing overseas investments, joint ventures, and the financial structure of overseas subsidiaries.

Mark Eaker

156

Navigation Using Signals from High-Altitude Satellites  

Microsoft Academic Search

If electronics can be satisfactorily applied to celestial navigation, a system having universal coverage without weather limitations might be produced. Radio stars are not a promising possibility, but the sun and moon are being tracked by the U. S. Navy Radio Sextant, AN\\/SRN-4, to provide limited coverage. Universal coverage might be achieved by the addition of artificial earth satellites. Satellites

Alton Moody

1960-01-01

157

A Satellite Study of VLF HISS.  

National Technical Information Service (NTIS)

Broad-band VLF radio noises from about 4 kc/s to above 10 kc/s are frequently observed near the auroral zone with the Injun 3 satellite. These broad-band VLF radio noises are called VLF hiss. In this study we select VLF hiss events for analysis by requiri...

D. A. Gurnett

1966-01-01

158

NOAA's Satellites  

NSDL National Science Digital Library

The National Oceanic & Atmospheric Administration (NOAA) maintains this centralized resource on NOAA satellites, of interest to life and physical scientists alike. Featured and described here are NOAA's National Environmental Satellite, Data and Information Service (NESDIS); NOAA's CoastWatch Program; and hundreds of Archived Satellite Images, Storm Animations and Special Events. Each section of the site points users to wealth of further information, spanning the technology of satellites to real-time satellite images. For users ranging from the curious student to the driven researcher, this site plays a central role in organizing NOAA satellite information.

159

Satellite reconnaissance  

NASA Astrophysics Data System (ADS)

The potential of the observation equipment in remote sensing satellites is described. United States meteorology, land use and oceanography satellites and the major US Earth observation programs are listed. Imaging satellite systems are described such as: visible light and near infrared, thermal IR window, and microwave window. It is concluded that a geometrical resolution between 10 and 40 m can be expected. In order to reduce the data flow from the satellite system the input side of the system (the object-sensor interaction) has to be known. Satellites with synthetic aperture radar are increasingly important, but satellites can never fully replace observations with aircraft and drones.

Deloor, G. P.

1984-06-01

160

Radio wave.  

PubMed

In developing countries with high rates of poverty and illiteracy, radio is emerging as an excellent medium for delivering information on health issues, family planning, nutrition, and agricultural development. Since radio does not require wired electricity, it can reach remote rural populations. Surveys have found that between 50-75% of poor rural households in developing countries own radios, and the majority listen to educational radio at least once a week. A program that reaches the urban poor outside of Lima, Peru, has been instrumental in controlling the spread of cholera. A Bolivian station broadcasts 8 hours of literacy, health, agricultural, and cultural programming a day to an audience of more than 2 million Aymara Indians. Small village radio stations with a broadcast range of 15 miles can be established for under US$400 and can generally achieve sustainability through local fundraising events such as raffles. In many cases, listeners have become broadcasters at their local radio stations. PMID:12286181

Elkin, V

161

Astronomical principles of satellite positioning  

NASA Astrophysics Data System (ADS)

The Global Navigation Satellite Systems (GNSS) dominate the positioning technologies at the beginning of this millennium. The new concept, already common in all users' segments, refer to those radio-navigation systems providing highly precise time and position information, continuously and globally, disregarding the weather status. In the present paper, a comparison between the principles of celestial navigation and satellite navigation is intended, offering additional reasoning to conclude that the roots of the global satellite navigation systems are connected to the classical principles of celestial navigation.

Dragusan, Adrian; Lupu, Sergiu; Cojocaru, Stelian

2008-09-01

162

Nanotube radio.  

PubMed

We have constructed a fully functional, fully integrated radio receiver from a single carbon nanotube. The nanotube serves simultaneously as all essential components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A direct current voltage source, as supplied by a battery, powers the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, we demonstrate successful music and voice reception. PMID:17973438

Jensen, K; Weldon, J; Garcia, H; Zettl, A

2007-10-31

163

The advisability of competitive international satellites  

NASA Astrophysics Data System (ADS)

This analysis examines the legal, political, and economic issues raised by the applications of Orion Satellites Corporation and International Satellite, Inc., before the Federal Communications Commission. The proposals request approval for the establishment of communications satellite systems potentially competitive with the International Telecommunications Satellite Organization (INTELSAT), a consortium of 109 member nations, which currently maintains a monopoly of international communications satellite traffic. The breadth of consequences resulting from a positive FCC action warrants a close scrutiny of U.S. international foreign policy objectives.

Greenhalgh, D. I.

164

The satellite communications alternative for maritime safety  

Microsoft Academic Search

The current status of satellite communication technology for maritime users is surveyed, with an emphasis on emergency communication capabilities. Topics addressed include the organizational structure of Inmarsat, the present and planned Inmarsat space segment, the coastal and ship earth stations, the compact Standard-C terminal, the Enhanced Group Call system, and the L-band Satellite Emergency Position Indicating Radio Beacon. Consideration is

James L. Fear

1988-01-01

165

Ionospheric effects on satellite land mobile systems  

Microsoft Academic Search

Satellite-ground radio systems are now so sensitive that ionospheric changes can disrupt their performance. This paper discusses some satellite-to-ground propagation problems in the UHF and L bands caused by the Earth's ionosphere. Such problems include signal time delay, signal dispersion, Faraday rotation, and scintillation.

Kenneth Davies; Ernest K. Smith

2002-01-01

166

Mobile internet access using satellite networks  

Microsoft Academic Search

SUMMARY Satellites offer a promising alternative for mobile access to the Internet by both pedestrians, and more importantly, from vehicles. As such, satellites provide an essential complement to the cellular radio (UMTS) infrastructure in sparsely populated areas where high bandwidth UMTS cells cannot be economically deployed. In this paper, we analyse various mobile Internet applications in representative urban scenarios for

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

2004-01-01

167

Maritime and Aeronautical Satellite Navigation Systems  

Microsoft Academic Search

This paper inciudes a brief survey of the generic types of radio navigation aids, including satellite navigation; then a more detailed review of the TRANSIT and NAVSTAR systems, thus encompassing the principal developmental and operational satellite navigation systems. The precision and accuracy of these systems, their basic operating characteristics, and the ancillary equipment required for their operations will be covered.

J. Litton

1977-01-01

168

The Direct Satellite Connection: Definitions and Prospects.  

ERIC Educational Resources Information Center

|Defines direct satellite broadcasting as the transmission of broadcast signals via high-powered satellites that permit direct reception of television or radio programs by means of small antennas. Outlines American, European, and Japanese plans for direct-to-home television reception and implications for the broadcasting industry. (JMF)|

Wigand, Rolf T.

1980-01-01

169

Corporate strategy and the Social Networking phenomena  

Microsoft Academic Search

The Social Networking (SN) phenomena has developed relatively overnight and is continuing to develop at an exponential pace. It allows for innovative new methods of disseminating and collecting information in ways never before dreamed possible by corporate executives. The rise of Social Networking is becoming a disruptive technology for traditional marketing and advertising medium such as radio, television, web page,

Robert L. Johnson

2010-01-01

170

Tadpole Satellite.  

National Technical Information Service (NTIS)

A low cost synchronous orbit satellite to evaluate small mercury bombardment ion thruster applications is described. The ion thrusters provide the satellite with precise north-south and east-west stationkeeping capabilities. In addition, the thrusters are...

1974-01-01

171

Meteorological Satellites.  

National Technical Information Service (NTIS)

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'...

A. Schnapf A. Schwalb B. C. Diesen L. J. Allison P. S. Martin

1980-01-01

172

Satellite reconnaissance  

Microsoft Academic Search

The potential of the observation equipment in remote sensing satellites is described. United States meteorology, land use and oceanography satellites and the major US Earth observation programs are listed. Imaging satellite systems are described such as: visible light and near infrared, thermal IR window, and microwave window. It is concluded that a geometrical resolution between 10 and 40 m can

G. P. Deloor

1984-01-01

173

Educational Radio.  

ERIC Educational Resources Information Center

This report summarizes information about the history, technology, and operation of educational radio in the U.S. Also presented are the Federal Communications Commission's (FCC) rules and regulations concerning the licensing and channel assignment of educational radio, and its auxiliary special broadcast services. Included are the application…

Federal Communications Commission, Washington, DC.

174

Radio Memories  

NSDL National Science Digital Library

The "Golden Age of Radio" that arguably lasted until the early 1950s may be hard to imagine today in an era of swirling iPod playlists and other genre-bending devices and technologies, but during this time the radio reigned supreme. People tuned in every week to hear the exploits of Flash Gordon, Sam Spade, and Amos n' Andy. Thanks to the Radio Memories website, many of these memories can be relived, or just experienced for the first time. Started in May 2005, the site contains a host of compelling programs, including episodes from the Interplanetary Adventures of Flash Gordon and a number of original episodes of the fabled Radio Detective Story Hour. If those types of programs fail to pique the interest of the casual visitor, the site also contains archived shows that explore the world of radio soap operas from the 1940s and the musical worlds of such stars as Tommy Dorsey and Harry James.

175

Studies of radio-wave propagation in the solar system  

Microsoft Academic Search

A review is given of studies of radio-wave propagation in the solar system that were conducted from 1963 to 1973 with the Soviet spacecraft Venera, Mars, and Luna. Results are presented for satellite radio-occultation investigations of the Martian atmosphere. Properties of radio-wave propagation in the dense atmosphere of Venus, involving a radio link with descending spacecraft, are examined along with

M. A. Kolosov; O. I. Iakovlev

1975-01-01

176

Transport layer protocols and architectures for satellite networks  

Microsoft Academic Search

SUMMARY Designing efficient transmission mechanisms for advanced satellite networks is a demanding task, requiring the definition and the implementation of protocols and architectures well suited to this challenging environment. In particular, transport protocols performance over satellite networks is impaired by the characteristics of the satellite radio link, specifically by the long propagation delay and the possible presence of segment losses

Carlo Caini; Rosario Firrincieli; Mario Marchese; Tomaso de Cola; Michele Luglio; Cesare Roseti; Nedo Celandroni; Francesco Potorti

2007-01-01

177

Solar Paddle Antenna Mounted on Pico-Satellite \\  

Microsoft Academic Search

This paper describes solar paddle antenna proposed in the development of Kagawa Satellite “KUKAI.” KUKAI is a mother-daughter pico-satellite for technical verification of a tethered space robot. The mother and the daughter satellites communicate respectively with the ground station by amateur radio frequencies. For the purpose of simple deployment system on orbit and antenna directivity suitable for KUKAI, antenna, which

Masahiro Nohmi; Katsumi Oi; Satoshi Takuma; Masaaki Ogawa

2010-01-01

178

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.

179

Satellite positioning  

NASA Astrophysics Data System (ADS)

Geodetic positioning programs with the U.S. Navy Transit and GPS satellite systems and satellite laser ranging programs are described. As of 1982 the number of Doppler receivers had increased to over 16,000 units, 1000 with two-frequency geodetic apparatus. The Nova 1 satellite, launched in 1981, was a drag-free satellite, incorporating a single-axis disturbance compensation system (DISCOS) to continuously correct track aberrations due to perturbing forces acting on the satellite. One of the Transit system units, Nova 1 lowered the broadcast ephemeris prediction errors to 5-15 m rms, compared to the 5-70 m rms error for the Oscar satellite. The Navstar GPS system is in full engineering development and will lead to an 18 satellite configuration, with four in view from any point on earth. Global positioning accuracies of 10 m have been found in tests. The Lageos, Starlette, beacon Explorer-C, and Geos-3 satellites have been used in laser ranging experiments to measure polar motions by reflecting laser light from the ground off reflectors on the satellite surfaces. NASA is currently moving a transportable laser station to Easter Island to obtain an accuracy of 10 cm.

Hill, R. W.

1983-04-01

180

Satellite guide  

NASA Astrophysics Data System (ADS)

The University of Rhode Island's Sea Grant Program has published what it calls the first user's guide to environmental satellite data. Written by Peter Cornillon, an oceanographer at Rhode Island, the guide spells out which agencies distribute information from 14 environmental satellites. For those unfamiliar with remote-sensing techniques, the guide also delineates the various sensors the satellites carry and the types of information they produce. The heart of the looseleaf-formatted guide is an overview of the characteristics and objectives of each satellite and the characteristics of the data available.

181

Artificial Satellites  

NSDL National Science Digital Library

Over 2,000 man-made satellites are currently orbiting the Earth, providing a wide range of services like communications, remote sensing, and global positioning. As more are launched and new technologies are developed, they will play an increasingly important role in everyday life.The Tech Museum offers this site (1) dedicated to the basics of satellites and their functions. A Java program complements the Satellite Anatomy section, which illustrates the standard components of three different categories of satellites. More information specific to satellite launches and their orbits can be found here (2). Most of the material is composed of fun experiments that demonstrate satellite operation. One of the most interesting features on this NASA site (3) is the Live 3D Java Tracking Display, which shows hundreds of different satellites and their current position in orbit. A few selected news articles and a separate section on satellite applications are also provided. The European Space Agency provides a look at solar power satellites (4), which could essentially "beam" energy to Earth. While it is not a new concept, the sheer magnitude of a project to construct a solar power satellite has thus far been too great to justify an attempt. At a conference held in December 2002 (5), representatives from the satellite industry convened to discuss current developments. Although many of the articles only address industry outlooks, some are more technology-oriented. For instance, one considers a new navigation system that could improve overall coverage and signal availability. A lesson plan (6) for grades K-5 teaches children how satellites are launched and some basic terminology. The activity uses different sized marbles, clay, and some other items to demonstrate fundamental concepts. Satellites of the Global Positioning System are being used for more than they were originally intended in England. This news article (7) describes how they are used to study earthquakes and corresponding movements in the Earth's crust. In other news (8), the largest communications satellite ever built was lost in November 2002. The failure of one of its launching rockets resulted in the satellite falling in a decaying orbit until it fell into the sea.

Leske, Cavin.

2003-01-01

182

A Study of Public Radio Stations' Educational Services, 1978-79.  

ERIC Educational Resources Information Center

|This second national survey of public radio stations' involvement in educational services to schools, colleges, and universities was conducted by the Corporation for Public Broadcasting (CPB) for use by individual public radio stations, educational agencies, and other organizations interested and involved in planning public radio's services to…

Corporation for Public Broadcasting, Washington, DC.

183

New trends in laser satellite communications: design and limitations  

Microsoft Academic Search

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

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

2008-01-01

184

The concept of an integrated terrestrial\\/land mobile satellite system  

Microsoft Academic Search

Potential satellite markets in the public safety (disaster relief, emergency medical, and law enforcement) and common carrier (mobile radio telephone) service areas are identified. The public mobile telephone segment is then examined to illustrate a methodology for identifying a potential satellite addressable market, including capacity requirements for roughly sizing a satellite. It is postulated that satellites could serve this lower

G. H. Knouse; P. A. Castruccio

1981-01-01

185

The concept of an integrated terrestrial\\/land mobile satellite system  

Microsoft Academic Search

Potential satellite markets in the Public Safety (disaster relief, emergency medical and law enforcement) and Common Carrier (mobile radio telephone) service areas are identified. The public mobile telephone segment is then examined to illustrate a methodology for identifying a potential satellite addressable market, including capacity requirements for roughly sizing a satellite. It is postulated that satellites could serve this lower

G. H. Knouse; P. A. Castruccio

1980-01-01

186

Corporate Governance and Control  

Microsoft Academic Search

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

Patrick Bolton; Marco Becht; Alisa Roell

2002-01-01

187

Controlling satellite communication system unwanted emissions in congested RF spectrum  

NASA Astrophysics Data System (ADS)

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

Olsen, Donald; Heymann, Roger

2007-09-01

188

Radio interferometry  

NASA Astrophysics Data System (ADS)

Geodetic and geophysical applications of radio interferometry are reviewed for the period 1987-1990. Emphasis is placed on geodetic very long baseline interferometry using Mark III and IIIA technology. Consideration is also given to observing campaigns and activities, data analysis techniques, and technique improvements.

Ray, Jim R.

189

47 CFR 76.66 - Satellite broadcast signal carriage.  

Code of Federal Regulations, 2012 CFR

...RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Carriage of Television Broadcast Signals § 76.66 Satellite...for point-to-multipoint distribution of television station signals, and that owns or...

2012-10-01

190

47 CFR 76.66 - Satellite broadcast signal carriage.  

Code of Federal Regulations, 2011 CFR

...RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Carriage of Television Broadcast Signals § 76.66 Satellite...for point-to-multipoint distribution of television station signals, and that owns or...

2011-10-01

191

Beyond the Ionosphere: Fifty Years of Satellite Communication.  

National Technical Information Service (NTIS)

Partial Contents: Radio Versus Cable: 'International Telecommunications Before Satellites'; 'Moon in Their Eyes: Moon Communication Relay at the Naval Research Laboratory, 1951-1962'; 'Moon Relay Experiments at Jodrell Bank'; 'Something of Value: Echo and...

A. J. Butrica

1997-01-01

192

Private land mobile radio services; amendment of the Commission's rules concerning general eligibility in the industrial radio services: Federal Communications Commission. Final rule.  

PubMed

This document adopts a rule amendment to permit the licensing of non-profit corporations and associations of eligible users in the Business and Special Industrial Radio Services in the bands below 512 MHz. The FCC now permits the licensing of non-profit corporations and associations of eligible users in each of the Industrial Radio Services except the Business and Special Industrial Radio Services below 800 MHz and permits it in all Industrial Radio Services including Business and Special Industrial above 800 MHz. The amendment will eliminate this exception. PMID:10254375

1982-02-10

193

Radio occultation data analysis by the radioholographic method  

Microsoft Academic Search

The radioholographic method is briefly described and tested by using data of 4 radio occultation events observed by the GPS\\/MET experiment on 9 February 1997. The central point of the radioholographic method (Pavelyev, 1998) is the generation of a radiohologram along the LEO satellite trajectory which allows the calculation of angular spectra of the received GPS radio wave field at

K. Hocke; A. G. Pavelyev; O. I. Yakovlev; L. Barthes; N. Jakowski

1999-01-01

194

The Mexican national satellite system  

NASA Astrophysics Data System (ADS)

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.

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

1983-10-01

195

GPS radio occultations with CHAMP: A radio holographic analysis of GPS signal propagation in the troposphere and surface reflections  

Microsoft Academic Search

Within the first nine months following the activation of the GPS radio occultation experiment aboard the low Earth orbiting satellite CHAMP, more than 25,000 occultation events have been observed. A radio holographic analysis of 3783 occultation events, recorded between 14 May 2001 and 10 June 2001, reveals that in about 20-30% of these events the received signal contains contributions from

G. Beyerle; K. Hocke; J. Wickert; T. Schmidt; C. Marquardt; C. Reigber

2002-01-01

196

GPS radio occultations with CHAMP: A radio holographic analysis of GPS signal propagation in the troposphere and surface reflections  

Microsoft Academic Search

Within the first nine months following the activation of the GPS radio occultation experiment aboard the low Earth orbiting satellite CHAMP, more than 25,000 occultation events have been observed. A radio holographic analysis of 3783 occultation events, recorded between 14 May 2001 and 10 June 2001, reveals that in about 20–30% of these events the received signal contains contributions from

G. Beyerle; K. Hocke; J. Wickert; T. Schmidt; C. Marquardt; C. Reigber

2002-01-01

197

Application of VLBI and satellite laser ranging to geodynamics  

Microsoft Academic Search

The NASA Crustal Dynamics Project has developed very-long baseline interferometer (VLBI) systems and satellite laser ranging (SLR) systems for geodynamics measurements. In VLBI, a radio noise signal from a distant quasar is received by two or more radio antennas and coherently recorded. These recordings are cross-correlated to determine the relative signal delays between stations which are used to derive the

R. J. Coates

1983-01-01

198

Ionospheric effects upon a satellite navigation system at Mars  

Microsoft Academic Search

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

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

2004-01-01

199

Loser: Consumer - Satellite TV Soccer Moms Will Hate  

Microsoft Academic Search

Sirius, first demonstrated, satellite TV for cars at the January 2003 Consumer Electronics Show in Las Vegas. They developed an impressive new transmission technology that breaks up the video signal and combines chunks of it with each of the more than 130 radio channels that fill Sirius's allocated 12.5 megahertz of spectrum. Existing radio receivers screen out that signal as

Tekla Perry

2008-01-01

200

Bringing the corporation into corporate branding  

Microsoft Academic Search

This paper describes corporate branding as an organisational tool whose successful application depends on attending to the strategic, organisational and communicational context in which it is used. A model to help managers analyse context in terms of the alignment between strategic vision, organisational culture and corporate image is presented. The model is based on a gap analysis, which enables managers

Mary Jo Hatch; Majken Schultz

2003-01-01

201

Sublime Satellites: from Cold War to Gulf War  

Microsoft Academic Search

Satellites are a sublime communication technology in the sense that they pursue a desire to escape the solidity, or even prison, of the Earth and to circulate in the realm of heavenly bodies stripped of terrestrial space-time coordinates. Satellites conquered orbital extraterrestrial space, colonized it for wealthy nation-states, enclosed it for private corporations, and exploited it for commercial and military

Rodney Giblett

2001-01-01

202

Corporate Initiatives Guidebook.  

National Technical Information Service (NTIS)

The purpose of this project was to study representative examples of corporate initiatives for downtown development and to develop a generic model for corporate response to center city economic development issues. Working through its network of local downt...

W. Black

1983-01-01

203

The concept, design, and operation of a demonstration holographic radio camera  

Microsoft Academic Search

Knowledge of the spatial characteristics and distribution of the irregularities in the ionosphere is fundamental to an understanding of the scintillation of VHF and UHF radio signals from satellites. As a means of obtaining this information radio frequency holograms of the ionosphere were recorded using the Holographic Radio Camera technique, and computer reconstructions were obtained.

W. R. Stone

1978-01-01

204

EARwitness Testimony: Applying Listener Perspectives to Developing a Working Concept of “Localism” in Broadcast Radio  

Microsoft Academic Search

Ever since the introduction of new technologies such as satellite, Internet and cable radio, the concept of “local” has been at the center of a debate in the radio industry. Ownership consolidation has led to concerns about the loss of “local identity.” Broadcast radio news providers are operating under the assumption that the geographical location of the origin of news

Gayane Torosyan; Charles Munro

2010-01-01

205

Space for celestial symphonies? Towards the establishment of international radio quiet zones  

Microsoft Academic Search

The growth of low- and medium-Earth orbit mobile satellite communications poses a threat to radio astronomers which could be mitigated by the establishment of international radio quiet zones (IRQZs), where communications traffic is managed (not eliminated) to allow radio astronomy to continue. Using the prototype of national such zones in the USA, this article explains how the system would work

Frans G. von der Dunk

2001-01-01

206

GPS radio occultation with CHAMP: An innovative remote sensing method of the atmosphere  

Microsoft Academic Search

The availability of Global Positioning System (GPS) radio signals has introduced a new promising remote sensing technique for the Earth's atmosphere. GPS based radio occultation exploit GPS signals received onboard a Low Earth Orbiting (LEO) satellite for atmospheric limb sounding. Temperature and water vapour profiles with high accuracy and vertical resolution can be derived from this measurements. GPS radio occultation

T. Schmidt; C. Marquardt; J. Wickert; G. Beyerle; C. Reigber; R. Galas; R. Koenig

2002-01-01

207

GPS radio occultation with CHAMP: an innovative remote sensing method of the atmosphere  

Microsoft Academic Search

The availability of GPS (Global Positioning System) radio signals has introduced a new promising remote sensing technique for the Earth’s atmosphere. GPS-based radio occultation exploits GPS signals received onboard a Low Earth Orbiting (LEO) satellite for atmospheric limb sounding. Temperature and water vapour profiles with high accuracy and vertical resolution can be derived from these measurements. The GPS radio occultation

T. Schmidt; J. Wickert; C. Marquardt; G. Beyerle; C. Reigber; R. Galas; R. König

2004-01-01

208

Plasma interactions of exoplanets with their parent star and associated radio emissions  

Microsoft Academic Search

The relatively high contrast between planetary and solar low-frequency radio emissions suggests that the low-frequency radio range may be well adapted to the direct detection of exoplanets. We review the most significant properties of planetary radio emissions (auroral as well as satellite induced) and show that their primary engine is the interaction of a plasma flow with an obstacle in

Philippe Zarka

2007-01-01

209

Remote Radio Sounding Science For JIMO  

Microsoft Academic Search

Radio sounding of the Earth's topside ionosphere and magnetosphere is a proven technique from geospace missions such as the International Satellites for Ionospheric Studies (ISIS) and the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE). Application of this technique to the Jupiter Icy Moons Orbiter (JIMO) mission will provide unique remote sensing observations of the plasma and magnetic field environments, and the

J. L. Green; B. W. Reinisch; P. Song; S. F. Fung; R. F. Benson; W. W. Taylor; J. F. Cooper; L. Garcia; T. Markus; D. Gallagher; P. Gogineni

2003-01-01

210

Radio-Holographic Location of Internal Waves in the Ionosphere and Atmosphere  

Microsoft Academic Search

A new radio-holographic method is introduced to locate layers in the propagation medium based on simultaneous observations of radio wave temporal amplitude and phase variations in satellite-to-satellite links The method determines position of a tangent point on the ray trajectory where gradient of refractivity is perpendicular to the ray trajectory and influence of a layered structure on radio wave parameters

A. G. Pavelyev; J. Wickert; Y. A. Liou; A. A. Pavelyev; T. Schmidt; K. Igarashi

2006-01-01

211

Reflections on corporate reputations  

Microsoft Academic Search

Purpose – The purpose of this paper is to illustrate the importance of corporate reputation to the management of contemporary organisations. Design\\/methodology\\/approach – The approach takes the form of survey research and case studies. The paper is informed by corporate image and reputation research undertaken for major international corporations, governments and NGOs in the UK and in countries throughout the

Robert Worcester

2009-01-01

212

The satellite communications alternative for maritime safety  

NASA Astrophysics Data System (ADS)

The current status of satellite communication technology for maritime users is surveyed, with an emphasis on emergency communication capabilities. Topics addressed include the organizational structure of Inmarsat, the present and planned Inmarsat space segment, the coastal and ship earth stations, the compact Standard-C terminal, the Enhanced Group Call system, and the L-band Satellite Emergency Position Indicating Radio Beacon. Consideration is given to the services available to Standard-C stations, distress and safety communication procedures, and the use of satellite communication to disseminate weather information. The equipment costs for various ship installations are indicated in a table.

Fear, James L.

1988-10-01

213

Satellite systems for Latin American telecommunication requirements  

NASA Astrophysics Data System (ADS)

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.

Elizondo, Eduardo L.

214

Satellite Telecommunications.  

ERIC Educational Resources Information Center

|This issue of a quarterly publication of the Council of Europe covers aspects of the history, technology, policies, and impact of telecommunications in Europe, with an emphasis on European television. The following articles are included: (1) "Man and the World of Telecommunications" (Piet Stoffelen); (2) "The European Communications Satellite

Forum, 1986

1986-01-01

215

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

ERIC Educational Resources Information Center

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

Texas Education Agency, Austin.

216

Observations of the ionosphere by the Ionosphere Sounding Satellite \\/ISS  

Microsoft Academic Search

The design and electronics of a global ionospheric sounding satellite are described. The satellite missions consisted of studying the global distribution of ionospheric critical frequencies and the virtual range vs frequency characteristics of the sounding echo; study of the global distribution of radio noise intensities and the occurrence frequency of atmospherics; study of such plasma parameters as electron and ion

N. Matuura; R. Nishizaki

1977-01-01

217

The rapid deployment digital satellite network  

Microsoft Academic Search

The ground mobile forces (GMF) satellite digital multichannel radio, which provided the US Marine Corps with the primary transmission links for its switched backbone during Operations Desert Shield and Desert Storm, is discussed. Reliable and highly mobile, the multichannel terminals provided clear and consistent digital pipelines for the Marine Corps circuit switched network and were rapidly deployed on military HWMMV

D. P. O'Neil

1992-01-01

218

Simulation techniques for mobile satellite channel  

Microsoft Academic Search

To evaluate the system performance for mobile satellite communications, it is necessary to take into account the effects of channel impairments by quantitative simulations. Although multipath fading is less destructive to signal propagation than in the case of land mobile radio, channel characterization is still of interest to system planners and designers. The research reported in the paper has resulted

Jone F. An; Ming H. Chen

1994-01-01

219

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

NASA Astrophysics Data System (ADS)

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.

Pinglier, A.

1980-02-01

220

Low-Altitude Remote Sensing with Unmanned Radio-Controlled Helicopter Platforms: A Potential Substitution to Satellite-based Systems for Precision Agriculture Adoption under Farming Conditions in Developing Countries  

Microsoft Academic Search

In developing countries with small and medium farm holdings, satellite-based remote sensing is found unsuitable for precision agriculture technology adoption, due to low spatial and high temporal resolution of imagery. Image acquisition system mounted on unmanned helicopter platforms can provide user-specified and near-real time images for quick assessment of the crop and soil status giving enough time for preventive measures.

Kishore C. Swain; H. P. W. Jayasuriya; V. M. Salokhe

221

The Control and Dissemination of Music in Corporate Controlled Markets  

Microsoft Academic Search

For the radio industry, music has become a tool for attracting listeners with the purpose of providing a specific demographic audience for corporate advertisers. As profit increasingly becomes a predominant focus, individual artistic expression and limited opportunity become a growing concern for aspiring musicians, producers and songwriters. This essay begins by demonstrating what hopeful artists often encounter when they begin

Robert Petti

2006-01-01

222

Radio Direction Finding.  

National Technical Information Service (NTIS)

Discussed in the book are the theoretical principles of radio direction finding and the operating principles of the various types of radio direction finders. Questions concerned with the practical use of ground station radio direction finders are reviewed...

E. S. Goikhman M. I. Rogatkin V. A. Vartanesyan

1970-01-01

223

Amateur Radio Service.  

National Technical Information Service (NTIS)

The Amateur Radio Service data file contains data for applicants and licensees operating under the Amateur Radio Service and the primary information is obtained from FCC Form 610, Application for Individual Amateur Radio Station and/or Operator License, a...

D. P. May

1978-01-01

224

Radio Astronomy Research.  

National Technical Information Service (NTIS)

Radio astronomy research has been carried out in the fields of high resolution interferometry, radio polarimetry, solar activity, and galactic and extragalactic radio sources, details of which are given in a bibliography of references to scientific journa...

R. N. Bracewell

1968-01-01

225

Frequency planning issues for direct broadcasting satellites  

NASA Astrophysics Data System (ADS)

In 1963, the International Telecommunication Union (ITU) defined the 'broadcasting satellite service' (BSS), taking into account the possibility of broadcasting directly from satellites to low-cost receiving terminals at individual homes or to more costly terminals at community centers. A World Administrative Radio Conference (WARC) was held in 1977 to carry out planning for the BSS band near 12 GHz. However, the countries of Region 2 (the Americas and Greenland) decided to postpone international BSS planning to a Regional Administrative Radio Conference (RARC) which was held in 1983. Meanwhile, in 1980, the Federal Communications Commission (FCC) began to develop domestic policies and procedures for the BSS. These policies and procedures were published in 1982. The present paper is concerned with the Direct Broadcast Satellite (DBS) frequency planning issues, taking into account the agreements and decisions made by WARC-77, RARC-83, and the FCC.

Reinhart, E. E.

226

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.

2004-07-14

227

Radio counterparts of gamma-ray pulsars  

NASA Astrophysics Data System (ADS)

Observations of pulsars with the Large Area Telescope (LAT) on the Fermi satellite have revolutionized our view of the gamma-ray pulsar population. For the first time, a large number of young gamma-ray pulsars have been discovered in blind searches of the LAT data. More generally, the LAT has discovered many new gamma-ray sources whose properties suggest that they are powered by unknown pulsars. Radio observations of gamma-ray sources have been key to the success of pulsar studies with the LAT. For example, radio observations of LAT-discovered pulsars provide constraints on the relative beaming fractions, which are crucial for pulsar population studies. Also, radio searches of LAT sources with no known counterparts have been very efficient, with the discovery of over forty millisecond pulsars. I review radio follow-up studies of LAT-discovered pulsars and unidentified sources, and discuss some of the implications of the results.

Guillemot, L.

2013-03-01

228

A bibliography of packet radio literature  

NASA Astrophysics Data System (ADS)

This bibliography is intended to contain all of the material on packet radio technology open to those within the packet radio community and, subject to possible limitations imposed by various contractors or autbors, available to the public. The titles are divided into two groups: those in the open literature and those published as corporation or agency reports. Corporate or agency reports are arranged chronologically. Many of the documents are progress reports and their title is of little help in determining content. In those instances a few key words are appended to the bibliographic entry to help guide any given inquiry. SRI, while compiling and distributing this list, does not have the documents from other contractors on file and therefore cannot provide them. All requests should be made to the individual contractor at the address given in the attachment.

1984-03-01

229

Learning radio astronomy by doing radio astronomy  

NASA Astrophysics Data System (ADS)

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.

Vaquerizo Gallego, J. A.

2011-11-01

230

Radio frequency interference  

Microsoft Academic Search

The article consists of a Powerpoint presentation on radio frequency interference. The areas discussed include: radio frequency interference; electromagnetic interference; mobile Internet device and wireless sensitivity requirement.

H. Skinner; K. Slattery

2008-01-01

231

Satellite broadcast usage and life test of high power S-band Traveling Wave Tube Amplifiers  

NASA Astrophysics Data System (ADS)

Broadcasting radio programs from satellites to mobile users has been operating for many years in the United States, Canada and South Korea. The service, generally called Satellite Radio, is provided at S-band radio frequencies. Satellite Radio users require near perfect service availability. Since most users are mobile (automobiles and handheld reception), the antennas of their receivers have little gain necessitating very high effective isotropic radiated power (EIRP) from the satellite to provide the required availability particularly under fading conditions. Despite using a satellite directive transmitting antenna, the achievement of this high EIRP requires a satellite transmitter radio frequency power output of over 7 kW. This is typically achieved by paralleling 32 Traveling Wave Tube Amplifiers (TWTAs). The configuration, usage and technical aspects of such satellite transmitters are described. These satellite transmitters are critical to Satellite Radio service both for performance and for operating lifetime, typically over 15 years. Because of this importance, detailed lifetime laboratory testing is being done on the TWTAs as reported herein.

Bosch, Ernst; Briskman, Robert D.; Foust, Joseph V.; Huebner, Karl-Heinz; Strauss, Robert

2012-12-01

232

How Satellites Work  

NSDL National Science Digital Library

Collection of seven classroom activities that focus on satellite technology. Topics include: coordinated universal time (UTC); satellite pass prediction; satellite design; satellite orbits; satellite launching; and, use of satellites in at-sea rescues. Each activity provides list of materials needed, background information, and procedure.

233

Microwave attenuation due to dust and sand storm in earth-satellite link  

Microsoft Academic Search

ldquoCrdquo band satellite communication service introduced in Mongolia in 1971, and then established Intersputnik and Intelsat earth stations. Nowadays, satellite based international telephone, data, television, radio broadcasting and VSAT services have been penetrated in public and private sector of Mongolia. In the near future, Ku and Ka bands will be used for the Mongolian satellite communication systems. ldr To determine

E. Norinpel

2007-01-01

234

Corporate Social Responsibility  

Microsoft Academic Search

\\u000a This chapter examines the ideas and ideology associated with the contemporary corporate social responsibility (CSR) movement,\\u000a and discusses how new approaches to corporate social responsibility are changing the relationship between the corporate and\\u000a third sectors. Changes in this relationship raise questions in turn about shifts in attitudes, behaviors, and practices within\\u000a third sector organizations as well as in their external

Brenda Gainer

235

Creating corporate advantage.  

PubMed

What differentiates truly great corporate strategies from the merely adequate? How can executives at the corporate level create tangible advantage for their businesses that makes the whole more than the sum of the parts? This article presents a comprehensive framework for value creation in the multibusiness company. It addresses the most fundamental questions of corporate strategy: What businesses should a company be in? How should it coordinate activities across businesses? What role should the corporate office play? How should the corporation measure and control performance? Through detailed case studies of Tyco International, Sharp, the Newell Company, and Saatchi and Saatchi, the authors demonstrate that the answers to all those questions are driven largely by the nature of a company's special resources--its assets, skills, and capabilities. These range along a continuum from the highly specialized at one end to the very general at the other. A corporation's location on the continuum constrains the set of businesses it should compete in and limits its choices about the design of its organization. Applying the framework, the authors point out the common mistakes that result from misaligned corporate strategies. Companies mistakenly enter businesses based on similarities in products rather than the resources that contribute to competitive advantage in each business. Instead of tailoring organizational structures and systems to the needs of a particular strategy, they create plain-vanilla corporate offices and infrastructures. The company examples demonstrate that one size does not fit all. One can find great corporate strategies all along the continuum. PMID:10179655

Collis, D J; Montgomery, C A

236

Satellite-to-satellite tracking orbit determination  

Microsoft Academic Search

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

B. T. Fang

1978-01-01

237

Hyperactive Chipmunk Radio  

Microsoft Academic Search

The hyperactive chipmunk radio modulates voice signals so that the radio waves behave the same in the radio medium as sound waves normally do in the acoustic medium. This is accomplished by segmenting the voice signal and compressing the segments in time before transmitting them through the radio channel. If the compression factor is correct, the distortion characteristics of the

G. H. McGibney; S. T. Nichols

238

The Radio Sonde  

Microsoft Academic Search

The radio sonde has been developed in recent years as a practical instrument for transmitting information from the stratosphere. This paper discusses some of the problems connected with the application of the radio-sonde principle to the radio meteorograph and also to the cosmic-ray radio sonde.

W. H. Pickering

1943-01-01

239

The Radio Amateur's Handbook.  

ERIC Educational Resources Information Center

|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…

Blakeslee, Douglas, Ed.

240

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, ÂÂ. is to promote young peopleÂs intellectual creative and professional growth through training and access to media and to produce the highest quality original media for local and national outlets. 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.

241

Radio-over-fiber networks for mobile communications  

NASA Astrophysics Data System (ADS)

Distributed antenna systems based on radio over fibre technology (fibre DAS) are becoming increasingly popular for providing cellular radio coverage within large buildings such as shopping centres, airports and corporate office blocks. The main limitation with fibre DAS, however, is its lack of flexibility for providing tailored radio coverage in multi-service or multi-operator environments. A new architecture, switched DAS, is proposed for these situations, which leads to both capital and operational cost savings as well as much greater operational flexibility

Wake, David; Beacham, Keith

2004-09-01

242

Corporate sponsored image films  

Microsoft Academic Search

The vast number of high quality corporate image and advocacy films, combined with the many other instruments of persuasion and control by corporations, powerfully direct the attitudes of the populace. In the absence of equal access, the best protection against deception from any powerful institution is skepticism — minds trained in critical thinking. But technically proficient, expensive films (costing from

James R. Bennett

1983-01-01

243

International Corporate Governance  

Microsoft Academic Search

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

Diane K. Denis; John J. McConnell

2001-01-01

244

International Corporate Governance  

Microsoft Academic Search

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

Diane K. Denis; John J. McConnell

2002-01-01

245

Corporate Crime and Restitution.  

ERIC Educational Resources Information Center

|Articulates need, nature, and form of a restitutionary approach to corporate crime. Considers small, in-prison production-oriented programs; residential in-community programs, and nonresidential in-community programs for individual offenders; also considers lump sum and continuous payments for corporations to make restitution. (NRB)|

Abel, Charles F.

1985-01-01

246

Entering the Corporate Market.  

ERIC Educational Resources Information Center

|This seminar guide was designed for use with a series of slides in training administrators to market an educational program or service to corporations. The seminar explains the following eight stages in planning entry into the corporate market: identifying appropriate publics; researching the market (analyzing supply and demand, collecting data,…

Greenshields, Garry W.

247

Lower Manhattan Development Corporation  

NSDL National Science Digital Library

While the search for closure and emotional healing continues for many New Yorkers and those who lost family in the tragic events that took place on September 11, 2001, the work of the Lower Manhattan Development Corporation moves on in an attempt to coordinate long term planning for the World Trade Center. Established by Governor Pataki and then-Mayor Rudy Giuliani, the LMDC is a joint state-city corporation governed by a 16-member board of directors. The site contains information on the Corporation's primary activities, including information about the memorial design competition for the site and the programs and resources for individuals, residents, and businesses in the area coordinated by the Corporation. Most recently, the Corporation has placed the proposed new World Trade Center site design concepts on the site for public examination. The design site concepts feature the work of seven internationally known firms, such as Richard Meier and Foster and Partners.

2002-01-01

248

Feasibility of microminiature satellites  

Microsoft Academic Search

A conceptual study is conducted on technical problems and system design techniques to accomplish higher performance microminiature satellites by smaller systems. Applications of microminiature satellite technology to practical satellite mission are mentioned. Concepts of microminiature satellites, measures to miniaturize satellites, and micro-miniaturization technologies for communication and data processing, electric solar power paddle, attitude and orbit control, structure, thermal control, propulsion,

Ryouichi Imai

1991-01-01

249

Outer planet satellites  

Microsoft Academic Search

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.

Paul M. Schenk

1991-01-01

250

Coping with Radio Frequency Interference  

NASA Astrophysics Data System (ADS)

The radio spectrum is a finite resource, on which humanity makes many demands. And pressure on it is ever increasing with the development of new technology and ideas for radio services. After all, we all benefit from wifi and cell phones. Radio astronomers have a small percentage of the spectrum allocated to them at octave intervals in the metre-centimetre bands, and at important frequencies, such as that of the 21cm line of HI. Signals from other services, as well as from our own poorly-engineered equipment, sometimes contaminate our bands: these signals constitute RFI. These may totally obliterate the astronomical signal, or, in the case of CLOUDSAT, may be capable of completely destroying a receiver, which introduces us to the new possibility of 'destructive interference'. A geo-stationary satellite can block access to a piece of sky from one site. Good equipment design eliminates self-inflicted interference, while physical separation often provides adequate practical mitigation at many frequencies. However, new observatories end up being located in the West Australian desert or Antarctica. In future they may be on the back side of the Moon. But there is no Earth-bound protection via physical separation against satellite signals. Some mitigation can be achieved by frequent data dumps and the excision of RFI, or by real-time detection and blanking of the receiver, or by more sophisticated algoriths. Astronomers of necessity aim to achieve mitigation via coordination, at the local level, and by participating in spectrum management at the national and international levels. This involves them spending a lot of time in Geneva at the International Telegraphic Union protecting their access to spectrum, and access to clean spectrum from the L3 point and the far side of the Moon.

Lewis, B. M.

2009-01-01

251

Error analysis of same-beam differential VLBI technique using two SELENE satellites  

Microsoft Academic Search

The Japanese SELENE project consists of a main satellite, a relay sub-satellite (Rstar), and a VLBI sub-satellite (Vstar). Rstar will relay the Doppler ranging signal between the main satellite and the ground station for the world’s first direct measurement of the gravity field on the far side of the Moon. The differential VLBI radio sources onboard Rstar and Vstar will

Q. Liu; F. Kikuchi; K. Matsumoto; K. Asari; S. Tsuruta; J. Ping; H. Hanada; N. Kawano

2007-01-01

252

Technical basis for the Geostationary Satellite Orbit Analysis Program (GSOAP), version 2  

Microsoft Academic Search

The Geostationary Satellite Orbit Analysis Program (GSOAP) is computer software that analyzes system performance and mutual interference of communication satellites using the geostationary satellite orbit. Calculation of the carrier-to-interference ratio margins is an essential part of GSOAP. It involves a (CIR) variety of technical problems, i.e., Earth-station and satellite antenna radiation patterns, radio wave propagation models, and related problems such

H. Akima

1985-01-01

253

The Earth as a Radio Source: Terrestrial Kilometric Radiation  

Microsoft Academic Search

Radio wave experiments on the Imp 6 and 8 satellites have shown that the earth emits very intense electromagnetic radiation in the frequency range of about 50-500 kHz. At peak intensity the total power emitted in this frequency range is about l09 W. The earth is therefore a very intense planetary radio source, with a total power output comparable to

Donald A. Gurnett

1974-01-01

254

Corporate governance as a determinant of corporate values  

Microsoft Academic Search

Purpose – This paper aims to test the impact of corporate governance structure on corporate values. Design\\/methodology\\/approach – The paper employs factor analysis and three-stage least squares to identify and explain variance in corporate values. Findings – In accordance with the proposed theoretical framework ownership, board and stakeholder structure are found to influence corporate values. When value determinants are taken

Steen Thomsen

2005-01-01

255

Value creation through corporate destruction? Corporate governance in shipping takeovers  

Microsoft Academic Search

This paper investigates corporate governance implications for shareholder value in shipping takeovers. Inadequate corporate governance structures are shown to affect corporate growth and even turn a company into a takeover target. The interesting case study of Stelmar Shipping is employed in an event study model, in order to evaluate the impact of takeover bids on corporate value and assess target

Theodore Syriopoulos; Ioannis Theotokas

2007-01-01

256

Corporate ethical consulting: Developing management strategies for corporate ethics  

Microsoft Academic Search

The increase of scandals in the business sector is forcing many companies to examine their corporate ethical behavior with a view toward rebuilding their corporate value system. This article describes how value-system reconstruction must proceed in a company and demonstrates that corporate ethics can only become plausible if based on a corporate ethical ethos. It outlines a five-step development plan

Richard H. Guerrette

1988-01-01

257

Satellite observations of transionospheric pulse pairs  

SciTech Connect

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.

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

1995-04-15

258

Development of 32-m Radio Telescopes for Monitoring Observations of Methanol Masers, H2O Masers, and Radio Continuum  

NASA Astrophysics Data System (ADS)

We report the renovation of two satellite-communication antennas, named Takahagi and Hitachi 32-m antennas, into cm-wave radio telescopes. Both antennas have been successfully renovated into radio telescopes until 2012. VLBI observations at 6.7, 8, and 22 GHz have been successful since 2010. We have started single-dish observations of methanol masers at 6.7 GHz and H2O masers at 22 GHz from 2013.

Yonekura, Y.; Saito, Y.; Saito, T.; Mori, T.; Soon, K. L.; Momose, M.; Yokosawa, M.; Ogawa, H.; Fujisawa, K.; Sugiyama, K.; Motogi, K.; Takaba, H.; Sorai, K.; Nakai, N.; Kameno, S.; Kobayashi, H.; Kawaguchi, N.; Hachisuka, K.

2013-10-01

259

Corporate Author Headings.  

National Technical Information Service (NTIS)

This list of corporate author headings represents a coordinated effort of Government agencies to facilitate the exchange of scientific and technical cataloging information. Of particular value are the extensive cross references which indicate variant name...

1970-01-01

260

Corporate Teaching Help Drops.  

ERIC Educational Resources Information Center

|Electronics, pharmaceuticals, and other industry programs to loan corporate employees to colleges and universities for short-term teaching assignments are discussed, including the advantages to both industry and the institutions and the conflicts in demand for specialists. (MSE)|

Sanger, David E.

1985-01-01

261

Principles of Radio Navigation.  

National Technical Information Service (NTIS)

The textbook for radio engineering higher institutions of learning and departments explains the operating principles of radio navigational aids used to navigate flying vehicles. General questions concerned with the accuracy of navigational fixes obtained ...

O. V. Belavin

1970-01-01

262

ITSY Handheld Software Radio.  

National Technical Information Service (NTIS)

Software radio technology promises to eliminate existing radio interoperability problems, provide a path for rapidly incorporating advances in digital communications, and enable new applications and waveforms that take advantage of the tremendous flexibil...

V. G. Bose

2001-01-01

263

Detecting Corporate Failure  

Microsoft Academic Search

\\u000a This article introduces definitions of the terms bankruptcy, corporate failure, insolvency, as well as the methods of bankruptcy,\\u000a and popular economic failure prediction models. We will show that a firm filing for corporate insolvency does not necessarily\\u000a fail to pay off its financial obligations as they mature. Moreover, we will assume an appropriate risk monitoring system centered\\u000a by well-developed failure

Yanzhi Wang; Lin Lin; Hsien-Chang Kuo; Jenifer Piesse

264

[Anorexia and corporal mediations].  

PubMed

The body, the central point of expression of the anorexic symptom, is an important therapeutic lever.The young anorexic girl protects herself through corporal hypertonicity. This tension is consistent with her fears of seeing her body becoming that of an adult and to feel emotions and sensations with too much force. Corporal mediation consists in helping the young girls get to grips with this body. PMID:23923454

Bureau, Hélène; Moro, Marie Rose

265

Corporate Governance and Economic Performance  

Microsoft Academic Search

What is the best corporate governance system? Is the Germanic corporate governance system the best? The Japanese? The Anglo?Saxon? This article reviews some of the relevant literature for answering this question. Particular attention is devoted to corporate governance problems in developing countries. It emphasizes that the nature of problems that corporate governance systems must deal with can be expected to

Dennis C. Mueller

2006-01-01

266

Cognitive Radio Architecture Evolution  

Microsoft Academic Search

The radio research community has aggressively embraced cognitive radio for dynamic radio spectrum management to enhance spectrum usage, e.g., in ISM bands and as secondary users in unused TV bands, but the needs of the mobile wireless user have not been addressed as thoroughly on the question of high quality of information (QoI) as a function of place, time, and

Joseph Mitola

2009-01-01

267

Commercial Radio as Communication.  

ERIC Educational Resources Information Center

|Compares the day-to-day work routines of commercial radio with the principles of a theoretical communication model. Illuminates peculiarities of the conduct of communication by commercial radio. Discusses the application of theoretical models to the evaluation of practicing institutions. Offers assessments of commercial radio deriving from…

Rothenbuhler, Eric W.

1996-01-01

268

Introduction to Radio Astronomy  

Microsoft Academic Search

A general description of the nature of radio astronomy, its differences from optical astronomy, a review of the earliest beginnings of galactic and solar radio astronomy, and a listing of other important observational discoveries is given. A nearly complete bibliography of these early publications and of the principal review books and papers on Radio Astronomy is given. Some practical aspects

F. T. Haddock

1958-01-01

269

Mobile communication via satellite towards the year 2000  

NASA Astrophysics Data System (ADS)

Recently, mobile communication services are dramatically growing, and there is an ever increasing demand for these services. INMARSAT (International Maritime Satellite Organization) plays a very important role to establish mobile communication networks for ships and airplanes on the global basis. For personal mobile communication, INMARSAT is currently studying INMARSAT-P hand-held terminal in its Project 21. Several mobile satellite communication systems such as IRIDIUM and Globalstar systems are also proposed in order to realize personal communication services towards the 21st century. This paper presents a recent trend of mobile satellite communication systems mainly aiming at the realization of personal communication services. Activities of CCIR (International Radio Consultative Committee) and major results of WARC (World Administrative Radio Conference) '92 are also briefly introduced focusing on mobile satellite matters.

Hirata, Yasuo

270

FORMOSAT-3\\/COSMIC GPS Radio Occultation Mission: Preliminary Results  

Microsoft Academic Search

The Formosa Satellite-3 and Constellation Observing System for the Meteorology, Ionosphere, and Climate (FORMOSAT-3\\/COSMIC) radio occultation (RO) mission has been successfully launched on April 14, 2006. The FORMOSAT-3\\/COSMIC mission uses global positioning system (GPS) signals to study the atmosphere and the ionosphere with global coverage. Receivers that are installed onboard of the six small FORMOSAT-3\\/COSMIC satellites register the phase and

Yuei-An Liou; Alexander G. Pavelyev; Shuo-Fang Liu; Alexey A. Pavelyev; Nick Yen; C.-Y. Huang; Chen-Joe Fong

2007-01-01

271

FORTE observations of lightning radio-frequency signatures: Capabilities and basic results  

Microsoft Academic Search

The FORTE satellite, launched on August 29, 1997, carries both radio-frequency-receiver and optical (imaging and photometric) payloads for the study of lightning. The radio-frequency (RF) data for the first 7 months of operation are described, both to illustrate the satellite{close_quote}s capabilities and to explain the basic statistical findings so far. FORTE{close_quote}s multichannel RF trigger system represents a significant advance in

Abram R. Jacobson; Stephen O. Knox; Robert Franz; Donald C. Enemark

1999-01-01

272

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".

273

Traffic capacity and QoS of personal mobile satellite systems with dynamic channel assignment  

Microsoft Academic Search

In this paper, radio resource management strategies optimizing the traffic capacity and the QoS (quality of service) of PMSSs (personal mobile satellite systems) are presented and described. The reference PMSS implemented in the in-house developed simulation tool MoSSS (mobile satellite system simulator) and used as a reference for performance evaluation of radio resource management strategies is introduced. All its relevant

Branko Bjelajac; Axel Nollchen; Thilo Christochowitz

1997-01-01

274

Feasibility study for a future Austrian lightning nano-satellite  

Microsoft Academic Search

A feasibility study for an Austrian lightning nano-satellite is presented. The satellite will carry a radio-frequency receiver payload for the investigation of electromagnetic signatures produced by lightning strokes. A special emphasis will be on the investigation of transient electromagnetic waves in VHF range (20-40MHz) known as sferics. The onboard RF lightning triggering system will be a special capability of the

Konrad Schwingenschuh; Ghulam Jaffer; O. Koudelka; S. Khan; C. Grant; M. Unterberger; Herbert Lichtenegger; W. Macher; W. Hausleitner

2008-01-01

275

Global satellite monitoring of the atmosphere and ionosphere  

Microsoft Academic Search

The possibilities of monitoring the atmosphere and ionosphere along satellite-to-satellite radio occultation paths are considered.\\u000a A relation between the amplitude and the phase of the signal sounding the medium is substantiated. Owing to this relation,\\u000a it is possible to separate the influence of layered and wave structures from the influence of turbulence in the atmosphere\\u000a and ionosphere. The possibility to

A. G. Pavelyev; S. S. Matyugov; O. I. Yakovlev

2008-01-01

276

Feasibility of microminiature satellites  

NASA Astrophysics Data System (ADS)

A conceptual study is conducted on technical problems and system design techniques to accomplish higher performance microminiature satellites by smaller systems. Applications of microminiature satellite technology to practical satellite mission are mentioned. Concepts of microminiature satellites, measures to miniaturize satellites, and micro-miniaturization technologies for communication and data processing, electric solar power paddle, attitude and orbit control, structure, thermal control, propulsion, and instrumentation systems are outlined. Examples of miniaturizing satellite missions such as planet exploration, low-altitude communication networks, space positioning system, low-altitude earth observation mission, clustered satellites, tethered satellites, and timely observation are described. Satellite miniaturizing technology can also be used to launch systems by lasers, and superconductive linear catapults (space escalator). It is pointed out that keys to promote satellite miniaturization are electronics, precision machining, raw material, electric power source technologies, and system design technology to integrate those technologies.

Imai, Ryouichi

1991-07-01

277

Protected transitional solution to transformational satellite communications  

NASA Astrophysics Data System (ADS)

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

Brand, Jerry C.

2005-06-01

278

Harbingers of sputnik: The amateur radio preparations in the Soviet Union  

Microsoft Academic Search

After recapitulating and re?evaluating the principal early signals that the Soviet Union was planning to launch an artificial earth satellite (Sputnik 1) in 1957, which have long been familiar to space historians, this article presents some additional pre?sputnik material from Radio, the Soviet government's monthly magazine for radio amateurs, and from other sources, which has not previously been identified by

Rip Bulkeley

1999-01-01

279

Outer planet satellites  

SciTech Connect

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.

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

1991-01-01

280

Radio occultation experiments with INAF-IRA radiotelescopes.  

NASA Astrophysics Data System (ADS)

The Radio Occultation research program performed at the Medicina and Noto Radioastronomical Stations of the Istituto Nazionale di Astrofisica (INAF) - Istituto di Radioastronomia (IRA) includes observations of spacecraft by satellite and satellite by satellite events. The Lunar Radio Occultation (LRO) part of the program consists in collecting data of the lunar Total Electron Content (TEC), at different limb longitudes and at different time, in order to study long term variation of the Moon's ionosphere. The LRO program started at Medicina in September 2006 with the observation of the European probe SMART-1 during its impact on the lunar soil. It proceeded in 2007 with the observation of the lunar occultations of Saturn and Venus, and with the observation of Mars in 2008. On this occasion the probes Cassini, Venus Express, Mars Express, Mars Reconaissance Orbiter and Mars Odissey were respectively occulted by the moon. On Dec 1st 2008 a Venus lunar occultation occurred. On that occasion we performed the first Italian-VLBI (I-VLBI) tracking experiment by detecting the carrier signals coming from the Venus Express (VEX) spacecraft with both the IRA radiotelescopes together with the Matera antenna of the Italian Space Agency. The second part of the radio occultation program includes the observation of satellite by satellite occultation events, as well as mutual occultations of Jupiter satellites. These events are referred to as mutual phenomena (PHEMU). These observations are aimed to measure the radio flux variation during the occultation and to derive surface spatial characteristics such as Io's hot spots. In this work preliminary results of the Radio Occultation program will be presented.

Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.

281

Corporate marketing: apocalypse, advent and epiphany  

Microsoft Academic Search

Purpose – Corporate marketing is a marketing and management paradigm which synthesises practical and theoretical insights from corporate image and reputation, corporate identity, corporate communications and corporate branding, among other corporate-level constructs. The purpose of this paper is to explain the nature and relevance of corporate marketing and to detail the antecedents of the territory. Design\\/methodology\\/approach – Via the adoption

John M. T. Balmer

2009-01-01

282

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

Microsoft Academic Search

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

K. Baker; D. Jansson

1994-01-01

283

Building and Operating Weather Satellite Ground Stations for High School Science. Teachers Guide.  

ERIC Educational Resources Information Center

|Automatic Picture Transmission (APT) images are real-time weather pictures transmitted from satellites on a radio frequency in a video format. Amateur radio enthusiasts and electronic experimenters have for a number of years designed, built, and operated direct readout stations capable of receiving APT photographs. The equipment to receive…

Summers, R. Joe; Gotwald, Timothy

284

Observations of the 557 GHz Line of Water in Comet C/2001 A2 (LINEAR) with the Odin Satellite  

NASA Astrophysics Data System (ADS)

Odin is a small astronomical/aeronomical satellite which was launched in February 2001. One of its capacities is the observation of the 110--101 line of water at 557 GHz with a high spectral resolution (corresponding to 80 m s-1) and a spatial resolution of 2 arcmin. During its commissioning phase, Odin observed comet C/2001 A2 (LINEAR) several times in April and from June 20 until July 9, 2001. From a preliminary analysis, 10 x 10 arcmin mapping of the 557 GHz water line on July 1.5--2.4 UTC shows that the H2O coma is elongated along the comet-Sun line. The line shape is asymmetric, which may be attributed to self-absorption in the foreground of the coma. The line width indicates a H2O outflow velocity of 0.7 km s-1. The integrated line intensity peaks at 12 K km s-1 on the main-beam brightness temperature scale. The corresponding water production rate is estimated at 3.8 x 1028 molecules s-1 for July 1.7--2.0. The outflow velocity and water production rate agree with independent observations of the 18 cm lines of OH at the Nançay radio telescope. Odin (http://www.snsb.se/odin/odin.html) is a Swedish-led satellite project funded jointly by SNSB (Sweden), CSA (Canada), Tekes (Finland) and CNES (France), Swedish Space Corporation being the prime contractor.

Biver, N.; Lecacheux, A.; Crovisier, J.; Bockelée-Morvan, D.; Rickman, H.; Lagerkvist, C. I.; Winnberg, A.; ODIN Team

2001-11-01

285

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

ERIC Educational Resources Information Center

|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…

Smith, William E.

286

Radio and distance learning in Pakistan.  

PubMed

Radio is a powerful communication vehicle in Pakistan able to reach 3/4 of urban and 2/3 of rural households. Until 1974, most radio broadcasts of the Pakistan Broadcasting Corporation, a state monopoly, were in the categories of music, drama, and features; news and current affairs; and religious broadcasts. The Allama Iqbal Open University (AIOU), a distance learning educational institution, was established through an act of the Pakistan Parliament in 1974 and is the only institution in the country to use radio broadcasts for its curriculum. Also established in 1974 within the AIOU was the Institute of Educational Technology (IET). The IET channels the transmission and flow of well-designed educational messages and lessons from the teachers to the students by employing distance teaching methodology that seeks to reinforce students' weekly lessons. IET closely integrates its activities within the University's academic departments. IET staff members not only participate in the development of course curriculum and syllabi, but also help to identify course content needing reinforcement through radio. While the teachers at AIOU convert the course curricula into distance-learning self-study activity-oriented correspondence texts, IET producers transcribe these scripts into actual production scripts. Feedback from students and findings of the University's Research and Statistical Cell are used to make revisions in the scripts. The AIOU enrolls an average of 100,000 students each year. Expansion is being limited only by the costs of purchasing time from the Pakistan Broadcasting Corporation (Rs 2000 for a 15-minute lesson) and the availability of appropriate time slots. PMID:12281001

Abbas, R

1987-01-01

287

The attenuation of UHF radio signals by houses  

Microsoft Academic Search

The results of a measurement program that was conducted to determine the attenuation of UHF radio signals penetrating to the inside of a typical house is presented. This program is part of a study to determine the feasibility of using direct satellite communication to disseminate disaster warning messages. The measurements were made in a manner to determine the building attenuation

P. I. Wells

1977-01-01

288

Atmosphere sounding by GPS radio occultation: First results from CHAMP  

Microsoft Academic Search

The first radio occultation measurements of the CHAMP (CHAllenging Minisatellite Payload) satellite using Global Positioning System (GPS) signals have been performed on February 11, 2001. By the end of April 2001 more than 3000 occultations were recorded. Globally distributed vertical profiles of dry temperature and specific humidity are derived, of which a set of 438 vertical dry temperature profiles is

Jens Wickert; Christoph Reigber; Georg Beyerle; Rolf König; Christian Marquardt; Torsten Schmidt; Ludwig Grunwaldt; Roman Galas; Thomas K. Meehan; William G. Melbourne; Klemens Hocke

2001-01-01

289

Radio frequency interference at passive microwave earth observation frequencies  

Microsoft Academic Search

The retrieval of geophysical parameters of the Earth and its atmosphere from satellite observations fundamentally relies upon the accuracy of the measurements. The growth in communication technologies has led to the exploitation of regions of the electromagnetic spectrum hitherto primarily used for Earth observation. This article describes and maps the distribution of radio frequency interference in the microwave portion of

C. Kidd

2006-01-01

290

Radio-wave propagation for space communications systems  

Microsoft Academic Search

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,

L. J. Ippolito

1981-01-01

291

Profiling the Atmosphere Using the Airborne GPS Radio Occultation Technique: A Sensitivity Study  

Microsoft Academic Search

Global Positioning System (GPS) radio occultation (RO) sounding, with its high vertical resolution temperature and humidity profiling capability, is revolutionizing atmospheric science, particularly through assimilation in numerical weather prediction (NWP) models. Currently, the observations are derived from GPS receivers onboard low Earth orbiting satellites. However, with the current number of satellites, it is difficult to provide dense sounding measurements in

Feiqin Xie; Jennifer S. Haase; Stig Syndergaard

2008-01-01

292

The Soviet navigation satellites  

NASA Astrophysics Data System (ADS)

The list of the satellites officially recognized as navigation satellites is drawn up, together with the much longer list of the satellites which might be recognized as such. A survey is made of the clues which enable to corroborate or contradict the presumed navigation mission of those satellites. The development of the navigation satellites programmed is reconstructed and some details on the two big classes of navigation satellites put into circular orbits at altitudes of around 1000 and 19,000 kilometers are given.

Laurent, D.

293

Satellite image eavesdropping: a multidisciplinary science education project  

NASA Astrophysics Data System (ADS)

Amateur reception of satellite images gathers a wide number of concepts and technologies which makes it attractive as an educational tool. We here introduce the reception of images emitted from NOAA series low-altitude Earth-orbiting satellites. We tackle various issues including the identification and prediction of the pass time of visible satellites, the building of the radio-frequency receiver and antenna after modelling their radiation pattern, and then the demodulation of the resulting audio signal for finally displaying an image of the Earth as seen from space.

Friedt, Jean-Michel

2005-11-01

294

Corporate branding with the help of corporate real estate  

Microsoft Academic Search

Nowadays, many companies try to attract customers by bundling all marketing efforts under a common corpo- rate brand to reflect the organization's identity. The principle of corporate branding suggests that the corporate brand ought to be thoroughly embedded throughout the entire company in order to be successful. Therefore, also Corporate Real Estate (CRE) must be managed in accordance with it.

HAJA Appel-Meulenbroek; Dave Havermans; Anneke van Kempen

2000-01-01

295

Ownership structure, corporate governance and corporate performance in Malaysia  

Microsoft Academic Search

Purpose – Following the 1997 Asian financial crisis, the Malaysian Government introduced new regulations on corporate governance, recognizing the importance of restoring market confidence. The purpose of this paper is to evaluate the impact of the implementation of these new regulations on corporate performance. Design\\/methodology\\/approach – Regression analysis was performed to examine factors influencing corporate performance. Ownership structure was represented

Nazli Anum Mohd Ghazali

2010-01-01

296

US Radio Broadcasting Past  

NSDL National Science Digital Library

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.

White, Thomas W.

2007-02-11

297

Trends in satellite communications and the role of optical free-space communications [Invited  

Microsoft Academic Search

Feature Issue on Optical Wireless Communications (OWC) The communication needs of Earth observation satellites is steadily increasing. Within a few years, the data rate of such satellites will exceed 1 Gbit\\/s, the angular resolution of sensors will be less than 1 murad, and the memory size of onboard data recorders will be beyond 1 Tbyte. Compared with radio frequency links,

Morio Toyoshima

2005-01-01

298

Satellite CNS for maritime transportation augmentation system (MTAS)  

Microsoft Academic Search

The development of the MTAS was to identify the possible applications for enhancement of digital selective call (DCS) MF\\/HF\\/VHF radio; satellite communications, navigation and surveillance (CNS); GPS and GLONASS; and safety systems including security and control of vessels, logistic and freight at sea, on inland waters and the security of crew and passengers on board ships, cruisers, boats and hovercrafts.

S. D. Ilcev

2009-01-01

299

National Radio Observatory  

NSDL National Science Digital Library

The National Radio Astronomy Observatory (NRAO) "operates powerful, advanced radio telescopes spanning the western hemisphere." The website is nicely divided into information for the general public, astronomers, and teachers and students. Users can learn all about NRAO's many telescopes located throughout the United States. Researchers can find out about meetings, conferences, software resources, and surveys. Amateur radio astronomers can find links describing how to build antennas and interferometers. Everyone will enjoy the numerous images of astronomical phenomena and NRAO's telescopes and facilities.

300

WCDMA Radio Interface  

Microsoft Academic Search

Understanding the WCDMA radio interface is essential for engineers dealing with UMTS radio networks. A knowledge of the structure\\u000a and usage of the physical channels in the downlink and uplink directions, together with a knowledge of spreading and modulation,\\u000a provides a good background for understanding how the WCDMA radio network works. Various kinds of services with different quality-of-service\\u000a requirements and

Matti Manninen

301

Dominion Radio Astrophysical Observatory  

NASA Astrophysics Data System (ADS)

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...

Murdin, P.

2000-11-01

302

Some radio meteor news  

NASA Astrophysics Data System (ADS)

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.

Rault, Jean-Louis

2013-01-01

303

Satellite RNAs and Satellite Viruses of Plants  

PubMed Central

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.

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

2009-01-01

304

Reporting corporate crime  

Microsoft Academic Search

Examines corporate fraud and its relationship with the media. Discusses rise in volume of fraud, due to technological advances, more teamwork and the involvement of organised crime. Looks at the decline in financial reporting this century, with the fourth estate or watchdog traditions of the press not overly concerned with financial news, due to the growth in market-driven journalism. This

Clem Lloyd; Paul Walton

1999-01-01

305

Contractual corporate governance  

Microsoft Academic Search

Companies have the choice to deviate from their national corporate governance standards by opting into another system. They can do so via contractual devices – such as cross-border mergers and acquisitions, (re)incorporations, and cross-listings – which enable them to choose their preferred level of investor protection and regulation. This paper reviews these three main contractual governance devices, their effect on

Marc Goergen; L. D. R. Renneboog

2008-01-01

306

GLOBALISATION AND CORPORATE POWER  

Microsoft Academic Search

This paper seeks to establish a view of the world within which globalisation and corporate power interact and shape the nature of the modern market economy. Drawing upon a range of theory and evidence, we consider the implications of the growth of transnational firms and concentrated market structures within the advanced industrial countries. We see ourselves as offering a framework

Keith Cowling; Philip R. Tomlinson

2005-01-01

307

The Corporate Classroom.  

ERIC Educational Resources Information Center

In many states, schools use programs developed by industry to teach about environmental issues. Corporate-sponsored curricula appear to expose children to knowledge about nature, energy use, solid waste, and recycling, but they often actually display an incomplete and self-serving picture that is raising concern among environmentalists and…

Stenger, Richard S.

1991-01-01

308

Error-free command link for sounding rockets and satellites  

NASA Astrophysics Data System (ADS)

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.

Ringstrand, Hans

2003-08-01

309

Satellite broadcasting in Europe  

NASA Astrophysics Data System (ADS)

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.

Bartholome, P.

1984-05-01

310

Aeronautical Mobile Satellite Experiment.  

National Technical Information Service (NTIS)

The various activities and findings of a NASA/FAA/COMSAT/INMARSAT collaborative aeronautical mobile satellite experiment are detailed. The primary objective of the experiment was to demonstrate and evaluate an advanced digital mobile satellite terminal de...

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

1990-01-01

311

Random Communication Satellite Coverage.  

National Technical Information Service (NTIS)

The report develops models for assessing credible satellite failure rates, population densities, coverage probabilities, and outage intervals. These models are interpreted in terms of the present random military communication satellite system. A sufficien...

C. S. Lorens

1967-01-01

312

Hurricane Katrina Satellite Imagery  

NSDL National Science Digital Library

This page provides access to a good number of satellite images of Hurricane Katrina taken by polar orbiting and geostationary satellites operated by NOAA. High resolution images are available on the site.

National Environmental Satellite, Data, and Information Service

313

The Kosmos Satellites.  

National Technical Information Service (NTIS)

The general principles and tasks of the 'Kosmos' satellites series were discussed. The operating principles of these satellites, the make-up of the service and scientific apparatus installed on them, and the most important scientific results obtained with...

Y. I. Zaytsev

1975-01-01

314

Corporate governance and liquidity management  

Microsoft Academic Search

This paper constructs an integrative indicator system of corporate governance, investigates the relation of corporate governance and liquidity, and illustrates investors' valuation of cash holding. Corporate governance significantly effects cash holding and cash value. Well-governed firms tends to hold less cash, and the cash value of them is higher than that of poorly-governed firms, which means investors pay liquidity premium

Boyan Liu; Zhebing Wang

2010-01-01

315

Corporate Largesse or Glad Hand?  

ERIC Educational Resources Information Center

|Gives a background on early educational sponsorship programs initiated by corporations. Discusses skepticism by consumers; Channel One and direct advertising to students; the need for schools to carefully manage relationships with corporations providing technology; and the necessity of corporate support for the future of technology in schools.…

Norton, Robert

1998-01-01

316

Corporate Largesse or Glad Hand?  

ERIC Educational Resources Information Center

Gives a background on early educational sponsorship programs initiated by corporations. Discusses skepticism by consumers; Channel One and direct advertising to students; the need for schools to carefully manage relationships with corporations providing technology; and the necessity of corporate support for the future of technology in schools.…

Norton, Robert

1998-01-01

317

Local Prosecutors and Corporate Crime  

Microsoft Academic Search

Based on a national survey and interviews, this article describes the attitudes and practices of local prosecutors regarding corporate crime. Although most local prosecutors did not regard corporate crime as a serious problem, their willingness to prosecute increases if an offense causes substantial harm and other agencies fail to act. Despite repeated calls for coordinated responses to corporate crime, relatively

Michael L. Benson; Francis T. Cullen; William J. Maakestad

1990-01-01

318

Creating corporate advantage through purchasing  

Microsoft Academic Search

Why do many corporate sourcing initiatives fail? In capturing corporate sourcing synergies CPO's need to manage the delicate balance between corporate synergy and decentralized business unit autonomy. This paper explains how CPO's may effectively capture purchasing synergies among individual business units. Based on our research, it will become clear that there are four important drivers for success: leadership & control,

Weele van AJ; FA Rozemeijer

2007-01-01

319

Accounting for Good Corporate Governance  

Microsoft Academic Search

Good corporate governance (GCG) is a mandatory requirement in today's corporate world by every stakeholder groups. Failure of giant corporate groups in last two-three decades strengthens the demand further. And surprisingly, in some of such failures, accounting as a discipline is held liable. The way accounting is practiced or the interpretations that may give different prescriptions in similar situations are

Nikhil Chandra Shil

2008-01-01

320

Global Corporate Security - Experiences & Lessons  

Microsoft Academic Search

This paper reviews the essential features of the philosophy of corporate security, its historical development and the growth of the impact of globalisation and the development of the corporate culture. The presentation will consider the impact of a range of external influences, including the New World Order, terrorism, environmentalism and the impact of litigation and changes in perception of corporate

Stewart Kidd

321

Modern Technologies: Satellites  

NSDL National Science Digital Library

The world's increasing dependence on satellites was recently made clear when a PanAmSat communications satellite went down, disrupting communication and data transmission around the world. The eight resources in this week's In the News highlight satellites, and the many important roles they play in our lives. Today, satellites are used to convey a wealth of information, from communications to important scientific data.

Harris, Kathryn L.

1998-01-01

322

Earth System: Satellites  

NSDL National Science Digital Library

There are thousands of artificial satellites circling our planet for navigation, communications, entertainment, and science. These satellites are an integral part of our everyday life, and they collect data which cannot be obtained from Earth's surface. This video segment describes the basic components of a satellite and some of applications that have been developed for both geostationary and orbiting satellites. The segment is three minutes fifty seconds in length. A background essay and discussion questions are included.

323

Operation of the Radio Occultation Mission in KOMPSAT-5  

NASA Astrophysics Data System (ADS)

Korea multi-purpose satellite-5 (KOMPSAT-5) is a low earth orbit (LEO) satellite scheduled to be launched in 2010. To satisfy the precision orbit determination (POD) requirement for a high resolution synthetic aperture radar image of KOMPSAT-5, KOMPSAT-5 has atmosphere occultation POD (AOPOD) system which consists of a space-borne dual frequency global positioning system (GPS) receiver and a laser retro reflector array. A space-borne dual frequency GPS receiver on a LEO satellite provides position data for the POD and radio occultation data for scientific applications. This paper describes an overview of AOPOD system and operation concepts of the radio occultation mission in KOMPSAT-5. We showed AOPOD system satisfies the requirements of KOMPSAT-5 in performance and stability.

Choi, Mansoo; Lee, Woo-Kyoung; Cho, Sungki; Park, Jong-Uk

2010-12-01

324

Geosynchronous satellites for MUOS  

Microsoft Academic Search

This paper proposes satellites in geosynchronous Earth orbit (GEO) for the mobile user objective system (MUOS). Each satellite has a large, deployable, multibeam antenna and onboard signal processing. The high directivity of the antenna enables small disadvantaged terminals with severe propagation impairments to reliably communicate via satellite and permits substantial frequency reuse. The design incorporates efficient access control, modulation, and

Samuel J. MacMullan; Christopher J. Karpinsky; Reuben E. Eaves; Andre R. Dion

1999-01-01

325

Satellite broadcasting in Europe  

Microsoft Academic Search

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

P. Bartholome

1984-01-01

326

Geostationary Satellite Server  

NSDL National Science Digital Library

This database contains imagery from geosationary satellites. Visitors can access daily images or archived imagery form GOES-9, METEOSAT, and other satellites. The imagery features hemispheric and whole-disk views of Earth, water vapor maps, and images of storms and other special events. Links to satellite homepages and to other related topics are included.

327

Digital communications by satellite  

Microsoft Academic Search

Topics in digital satellite communications are treated extensively for a readership of students or communications system designers acquainted with communications theory fundamentals and random processes. Major parts of the book are: signal quantizing and multiplexing; satellite communications; modulation and coding in distorted channels; worldwide timing by satellite relay. Some specific topics treated include: PCM quantizing, sampling of nonbandlimited signals, delta

J. J. Spilker Jr.

1977-01-01

328

Radio Frequency Interference: Radio Astronomy's Biggest Enemy  

NASA Astrophysics Data System (ADS)

As technology progresses, the demand for the usage of the electromagnetic spectrum increases with it. The development is so fast and prolific that clean band space for passive users such as Radio Astronomy is becoming ever so scarce. Even though, several spectral bands have been protected for Radio Astronomy by Federal Communication Commission (in the USA) under the recommendations of the International Telecommunication Union (ITU), pressure for making more spectral space commercially usable is extreme. Although these commercial usages make our modern living at all possible, often the extreme vulnerability of passive users are are not fully appreciated, resulting in unwanted emissions (RFI) in the Radio Astronomy Bands. Another source of RFI is the fact that many of the electronic devices used in the observatories themselves generate radio waves. If proper precautions are not taken, these can be received back through the Radio Telescope itself. This problem is referred to as internal RFI. The focus of this paper is the search and diminution of internal RFI in the Arecibo Observatory in Arecibo, Puerto Rico. Using a simple setup of a log-periodic antenna and a Spectrum Analyzer, spectra spanning a frequency range of 100 - 1800 MHZ were recorded in some areas of the Observatory and the new Visitor Center (AOVEF). The measurements disclosed sources of radio emission among some of the digital electronic equipment in the Equipment room and a few displays in the AOVEF. Most prominent of these was a 2.5 MHz comb spanning the entire range of the measurements emitted from the SRENDIP and AOFTM machines. The respective groups were informed and corrective shielding & isolations were implemented immediately. In AOVEF, three displays, some audio-visual equipment, and video/digital cameras used by the visitors were found to be "leaky". In future, the use of such cameras will be prohibited and the exhibits will be screened appropriately.

Acevedo, F.; Ghosh, Tapasi

1997-12-01

329

The Educational Radio Media  

Microsoft Academic Search

The undeniable affect of radio on the nation's economy, social structure, attitudes and behavior, not to mention marketing, business and industry, and the entertainment field has been great. But the modern broadcaster has a rather unique problem-- a problem of communication. All of the national effects of radio have caused the broadcaster to constantly review and update his knowledge in

JamesLTungate

1969-01-01

330

Radio Transmission Measurements  

Microsoft Academic Search

The paper divides naturally into three sections. The first section briefly analyses the radio transmission circuit into (a) the sending or radiating portion, (b) the transmitting portion consisting of the ether path thru which the radiated waves travel, and (c) the receiving portion. The relation of these from the standpoint of the radio transmission engineer is discussed, pointing out the

R. Bown; C. R. Englund; H. T. Friis

1923-01-01

331

Transatlantic Radio Telephone Transmission  

Microsoft Academic Search

The paper reports upon measurements of trans-Atlantic radio transmission which had been made during the past two years in a study of the possibilities of trans-Atlantic radio telephony. These measurements cover several different frequencies in the range below 60 kilocycles in both directions across the Atlantic and represent probably the most comprehensive study yet made of any transmission path. An

L. Espenschied; C. N. Anderson; A. Bailey

1926-01-01

332

Cognitive Radio Prototyping  

Microsoft Academic Search

Future wireless systems have been evolving toward a broadband and open architecture for efficient multi-service operation, which will have a great impact on the terminal and infrastructure component design methodology for supporting multiple radio schemes. Cooperation in wireless networks, requiring cognitive radio implementations, will facilitate a new dimension in the evolution of multimedia communications. The growing price pressure requires ever

Peter JUNG; Alexander VIESSMANN; Christoph SPIEGEL; A. Burnic; Z. Bai; G. H. Bruck; K. Statnikov; A. Waadt; S. Wang; X. Popon; R. R. Velilla; H. Saarnisaari; M. Alles; T. Brack; F. Kienle; F. Berens; S. Rotolo; F. M. Scalise; N. Wehn

2008-01-01

333

Designing Cognitive Radio Terminals  

Microsoft Academic Search

Ubiquitous broadband communications will be a major asset of future wireless systems, requiring a further evolution of the terminal and infrastructure component design which will need to supporting multiple radio schemes in multi- service environments. Cooperative networking, which sets out from cognitive radio implementations, will facilitate unprecedented flexibility and true multimedia. However, the price pressure mandates high integration efficiency and

Christoph Spiegel; Alexander Viessmann; Admir Burnic; Zijian Bai; Guido H. Bruck; Peter Jung; Konstantin Statnikov; Andreas Waadt; Shangbo Wang; Xavier Popon; Rafael Rodriguez Velilla; Harri Saarnisaari; Matthias Alles; Torben Brack; Frank Kienle; Friedbert Berens; Salvatore Rotolo; Fabio Mario Scalise; Norbert When

2008-01-01

334

Radio Mathematics in Nicaragua.  

ERIC Educational Resources Information Center

This document reports on the Radio Mathematics Project (RMP) over a five-year period. In 1973, the United States Agency for International Development (AID) asked the Institute for Mathematical Studies in the Social Sciences (IMSSS) at Stanford University to develop an instructional program with radio as the medium of delivery. IMSSS was to devise…

Friend, Jamesine, Ed.; And Others

335

Radio interferometric geolocation  

Microsoft Academic Search

We present a novel radio interference based sensor localization method for wireless sensor networks. The technique relies on a pair of nodes emitting radio waves simultaneously at slightly different frequencies. The carrier frequency of the composite signal is between the two frequencies, but has a very low frequency envelope. Neighboring nodes can measure the energy of the envelope signal as

Miklós Maróti; Péter Völgyesi; Sebestyén Dóra; Branislav Kusý; András Nádas; Ákos Lédeczi; György Balogh; Károly Molnár

2005-01-01

336

Deterministic Radio Broadcasting  

Microsoft Academic Search

. We consider broadcasting in radio networks: one node of thenetwork knows a message that needs to be learned by all the remainingnodes. We seek distributed deterministic algorithms to perform this task.Radio networks are modeled as directed graphs. They are unknown, inthe sense that nodes are not assumed to know their neighbors, nor thesize of the network, they are aware

Bogdan S. Chlebus; Leszek Gçasieniec; Anna Östlin; John Michael Robson

2000-01-01

337

Film, Radio, and Television.  

ERIC Educational Resources Information Center

|This journal issue covers the history of film, radio, and television in Iowa. The first article, "When Pictures and Sound Came to Iowa," summarizes the origin of movies and radio and their early beginnings in Iowa. Using old photographs and measurement charts, the viewing, reading, and listening habits of young people in 1950 and 1958 are…

Hardesty, Carolyn, Ed.

1990-01-01

338

Writing for Radio.  

ERIC Educational Resources Information Center

Describes a 24-hour commercial radio station simulation class project for eighth-grade language arts. Students wrote their own scripts, chose music and were disc jockeys on their own music and talk shows, and prepared news and traffic reports. Guest speakers from actual commercial radio came in to discuss issues such as advertising, censorship,…

Tupper, Marianna S.

1995-01-01

339

The Radio Universe  

NSDL National Science Digital Library

The Radio Universe website provides a brief introduction the electromagnetic radiation, HII regions, the structure of the Milky Way galaxy, and quasars as seen by radio wave observations. The site also contains an expliantion of the doppler effect and 21 cm line.

2005-06-07

340

Ultraviolet and radio flares from UX Arietis and HR 1099  

SciTech Connect

Simultaneous observations of the RS CVn systems UX Ari and HR 1099 with the IUE satellite and the VLA are presented. Flaring activity is observed at ultraviolet wavelengths with the IUE when none is detected at radio wavelengths with the VLA. Radio flares with no detectable ultraviolet activity have also been observed. Thus, flares in the two spectral regions are either uncorrelated or weakly correlated. The flaring emission probably originates in different regions at the two wavelengths. Radio flares from RS CVn stars may originate in sources that are larger than, or comparable to, a star in size. This is in sharp contrast to compact, coherent radio flares from dwarf M stars. The ultraviolet flares from RS CVn stars probably originate in sources that are smaller than a component star. 18 references.

Lang, K.R.; Willson, R.F.

1988-05-01

341

Radio search for gamma-ray pulsar counterparts  

NASA Astrophysics Data System (ADS)

The Fermi gamma-ray satellite, launched in June 2008 is already returning remarkable results. In particular, it has discovered a large number of gamma-ray pulsars without any known radio counterpart (where only 1 was known prior to launch) and has detected unknown sources of gamma-ray radiation in the galactic plane with arcmin positional accuracy. Here we request time to (a) search the gamma-ray pulsars for radio pulsations using very deep integrations at 1.4 GHz and (b) search the unidentified galactic plane sources for radio pulsars. Detecting (or not) pulsars in the former case will help to distinguish between models of gamma-ray emission in pulsars. Detection of radio pulsars in the latter case will enable a search for gamma-ray pulsations to be made and/or determine other causes (such as pulsar wind nebulae) for the gamma-ray emission.

Keith, Michael; Johnston, Simon; Romani, Roger W.; Thompson, David J.; Weltevrede, Patrick; Michelson, Peter

2009-04-01

342

Solar Radio Bursts with Drifting Stripes in Emission and Absorption  

NASA Astrophysics Data System (ADS)

This review covers fairly comprehensively experimental and theoretical research on the fine structure of types zebra pattern (ZP) and fiber bursts (FB) in solar type II + IV radio bursts. The basic attention is given to the latest experimental data. A comparative analysis of several recent solar type IV radio outbursts with these fine structure in dynamical radio spectra is carried out using available ground-based and satellite data (Yohkoh, SOHO, TRACE, RHESSI). New data on microwave zebra structures and fiber bursts testifies that they are analogous to similar structures observed at meter wavelengths. The discovery of the superfine structure, in the form of millisecond spikes is the most significant new effect in the cm range. All basic theoretical models of the zebra pattern and fiber bursts are discussed critically. Two main models are studied for their interpretation: (i) interactions between electrostatic plasma waves and whistlers, (ii) radio emission at double plasma resonance (DPR). The relative significance of several possible mechanisms remains uncertain.

Chernov, G. P.

2006-12-01

343

Neptune's radio emissions  

NASA Astrophysics Data System (ADS)

Different radio emissions observed by the Planetary Radio Astronomy (PRA) instrument during the inbound and outbound trajectories are reviewed. Two types of emissions (smooth and bursty) were recorded in the frequency range of 20 to 1300 kHz which differ in spectral, temporal, and polarization characteristics. The source location of the smooth radio emission have been determined through the observations at the closest approach when the radio source was occulted by the planet. Other types of emission detected by the PRA experiment include the fore shock of Neptune's magnetosphere and the impacts of dust at ring-crossings and different low frequency waves. It is concluded that there is at least one radio source in the auroral zone of the northern magnetic hemisphere where a good fit to the observations can be obtained when assuming an emission cone model.

Leblanc, Y.; Ladreiter, H. P.

1992-11-01

344

Local Oscillator Distribution Using A Geostationary Satellite  

NASA Astrophysics Data System (ADS)

A satellite communication system suitable for distribution of local oscillator reference signals for a widely spaced microwave array has been developed and tested experimentally. The system uses a round-trip correction method to remove effects of atmospheric fluctuations and radial motion of the satellite. This experiment was carried out using Telstar-5, a commercial Ku-band geostationary satellite. A typical Ku-band satellite has uplink and downlink capacity at 14 14.5 GHz and 11.7 12.2 GHz, respectively. For this initial experiment, both earth stations were located at the same site to facilitate direct comparison of the received signals. The local oscillator reference frequency was chosen to be 300 MHz and was sent as the difference between two Ku-band tones. The residual error after applying the round trip correction has been measured to be better than 3 ps for integration times ranging from 1 to 2000 s. For integration times greater than 500 s, the system outperforms a pair of hydrogen masers with the limitation believed to be ground-based equipment phase stability. The idea of distributing local oscillators using a geostationary satellite is not new; several researchers experimented with this technique in the eighties, but the achieved accuracy was 3 to 100 times worse than the present results. Since then, the cost of both leased satellite bandwidth and the Ku-band ground equipment has dropped substantially and the performance of various components has improved. An important factor is the availability of narrow bands which can be leased on a communications satellite. We lease three 100 kHz bands at approximately one hundredth the cost of a full 36 MHz-wide transponder. Further tests of the system using terminals separated by large distances and comparison tests with two hydrogen masers and radio interferometry of astronomical objects are needed.

Bardin, J.; Weinreb, S.; Bagri, D.

2004-06-01

345

Industrial Analytics Corporation  

SciTech Connect

The lost foam casting process is sensitive to the properties of the EPS patterns used for the casting operation. In this project Industrial Analytics Corporation (IAC) has developed a new low voltage x-ray instrument for x-ray radiography of very low mass EPS patterns. IAC has also developed a transmitted visible light method for characterizing the properties of EPS patterns. The systems developed are also applicable to other low density materials including graphite foams.

Industrial Analytics Corporation

2004-01-30

346

Corporate Responsibility und Sponsoring  

Microsoft Academic Search

\\u000a Anwaltskanzleien und Wirtschaftsprüfungsgesellschaften nutzen immer häufiger das breite Spektrum des Sponsorings als ein eigenständiges\\u000a Kommunikationsinstrument. Dabei ist die Definition, was unter Sponsoring verstanden wird recht uneinheitlich. Für bestimmte\\u000a Ausprägungen des Sponsorings trifft dies sicherlich zu. Jedoch gilt das Sponsoring eines Sportvereins, einer Charity-Veranstaltung\\u000a oder die großzügige Weihnachtsspende an ein Kinderhilfswerk oft auch als Ausweis gesellschaftlichen Engagements, auch Corporate\\u000a Responsibility (CR)

Sabine Reuss; Stefanie Wismeth

347

Korrespondenz und Corporate Identity  

Microsoft Academic Search

\\u000a Wally Olins schreibt in seinem Buch Corporate Identity: „Alles, was die Organisation tut, muss ihre Identität bekräftigen.\\u000a Die Produkte, die das Unternehmen herstellt oder verkauft, müssen seine Normen und Werte vermitteln. Die Gebäude, in denen\\u000a es Leistung erbringt und anbietet […], ihr Standort […] sind allesamt Ausdruck der Identität. Das Kommunikationsmaterial der\\u000a Firma, von der Werbung bis hin zur Bedienungsanleitung,

Wolf Scholz

348

The Gravity Fields of the Saturnian Satellites  

NASA Astrophysics Data System (ADS)

In its tour of the Saturnian system, begun on July 1st, 2004, the Cassini spacecraft had many close flybys of Saturn's main satellites. However, due to impossibility to carry out simultaneously remote sensing observations and microwave tracking from ground, only a small fraction of those flybys could be exploited for gravity measurements. So far, the quadrupole field has been mapped only for Titan, Rhea and Enceladus, while for Hyperion and Iapetus the mass was the only accessible parameter. For Titan and Enceladus, the only satellites targeted more than once for gravity observations, also a rough geoid to degree and order 3 has been determined. Satellite gravity investigations rely upon accurate measurements of the spacecraft range rate, enabled by coherent, two-way radio links at X and Ka band (8.4 and 32.5 GHz). The use of hydrogen masers frequency standards at the ground station and the consid-erable suppression of plasma noise at X and Ka band frequen-cies provide range rate accuracies of 10-30 micron/s at integra-tion times of 60 s. Thanks to the higher frequency of the radio link, these measurement accuracies are in the average a factor of 10 better than those attained by Galileo in its tour of the Jovian system. However, in order to attain a reliable determination of the low degree field, good measurements must be combined with appropriate flyby geometries and adequate sampling, a condition that necessarily requires multiple flybys. We review the main results obtained so far by Cassini for Titan, Rhea and Enceladus, and discuss the methods of analysis used by the Radio Science Team.

Iess, L.

2011-12-01

349

PARTNeR for Teaching and Learning Radio Astronomy Basics  

NASA Astrophysics Data System (ADS)

NASA has three satellite tracking stations around the world: CDSCC (Canberra, Australia), GDSCC (Goldstone, USA) and MDSCC (Madrid, Spain). One of the antennas located at MDSCC, DSS-61, is not used for satellite tracking any more and thanks to an agreement between INTA (Instituto Nacional de TA~l'cnica Aeroespacial) and NASA, it has been turned into an educational radio telescope. PARTNeR (Proyecto Académico con el RadioTelescopio de NASA en Robledo, Academic Project with the NASA Radio Telescope at Robledo) is a High School and University radio astronomy educational program that allows teachers and students to control this 34-meter radio telescope and conduct radio astronomical observations via the Internet. As radio astronomy is not a popular subject and astronomy has little presence in the High School Curriculum, teachers need specific training in those subjects to implement PARTNeR. Thus, High School teachers joining the project take a course to learn about the science of radio astronomy and how to use the antenna in their classrooms. Also, teachers are provided with some learning activities they can do with their students. These lesson plans are focused on the implementation of the project within an interdisciplinary framework. All educational resources are available on PARTNeR website. PARTNeR is an inquiry based approach to science education. Nowadays, students can join in three different observational programmes: variability studies in quasars, studies of radio-bursts in X-ray binaries (microquasars), and mapping of radio sources in the galactic plane. Nevertheless, any other project can be held after an evaluation by the scientific committee. The operational phase of the project started in the academic year 2003-04. Since then, 85 High Schools, seven Universities and six societies of amateur astronomers have been involved in the project. During the 2004-09 period, 103 High School teachers from Spain and Portugal have attended the training courses, and 105 radio astronomical remote observations have been performed with users. Until now, more than 2,000 students have been involved in radio astronomical observations.

Vaquerizo, Juan Ángel

2010-10-01

350

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.

351

Riding the Radio Waves  

NSDL National Science Digital Library

Through this lesson students learn how AM radios work through basic concepts about waves and magnetic fields. Waves are first introduced by establishing the difference between transverse and longitudinal waves, as well as identifying the amplitude and frequency of a given waveform. Students then learn general concepts about magnetic fields, leading into how radio waves are created and transmitted. Several demonstrations can be performed in order to help students better understand these concepts. The goal of this lesson is for students to understand how the AM radios built during the associated activity function.

Techtronics Program

352

Policies for regulation of direct broadcast satellites  

NASA Astrophysics Data System (ADS)

The potential market for satellite to home television broadcasting was examined and recommendations were made to the FCC concerning appropriate regulatory policies for direct broadcast satellites (DBS) for the period following the 1983 Regional Administrative Radio Conference (RARC). It is concluded that many substitutes for DBS will be available in the market for subscription video programming. Either conventional broadcast regulation, which assumes scarcity of channels, nor common carrier regulation, which assumes monopoly power will be appropriate. The report recommends several functions the Commission should perform because of its spectrum allocation responsibilities, but recommends that the Commission make no rules concerning compatibility, signal quality, ownership of receiving equipment, program content, prices, service offerings, or control of channels.

Setzer, F. O.; Franca, B. A.; Cornell, N. W.

1980-09-01

353

Satellite Threat Warning and Attack Reporting  

SciTech Connect

The Air Force Research Laboratory`s Satellite Threat Warning and Attack Reporting (STW/AR) program will provide technologies for advanced threat warning and reporting of radio frequency (RF) and laser threats. The STW/AR program objectives are: (a) develop cost- effective technologies to detect, identify, locate, characterize, and report attacks or interference against U.S. and Allied satellites. (b) demonstrate innovative, light-weight, low-power, laser and RF sensors. The program focuses on the demonstration of RF and laser sensors. The RF sensor effort includes the investigation of interferometric antenna arrays, multi-arm spiral and butler matrix antennas, wideband receivers, adaptive processors, and improved processing algorithms. The laser sensor effort includes the investigation of alternative detectors, broadband grating and optical designs, active pixel sensing, and improved processing algorithms.

Hilland, D. [Kirkland AFB, NM (United States). Air Force Research Lab.; Phipps, G. [Sandia National Labs., Albuquerque, NM (United States). Optics & Technologies Dept.; Jingle, C.; Newton, G. [Schafer Corp., Albuquerque, NM (United States)

1997-12-31

354

Digital audio and video broadcasting by satellite  

NASA Astrophysics Data System (ADS)

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.

Yoshino, Takehiko

355

A direct broadcast satellite-audio experiment  

NASA Astrophysics Data System (ADS)

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.

Vaisnys, Arvydas; Abbe, Brian; Motamedi, Masoud

1992-03-01

356

SERIES - Satellite Emission Range Inferred Earth Surveying  

NASA Astrophysics Data System (ADS)

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.

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

357

Atmospherics in relation to source phenomena and radio wave propagation in the VHF, UHF, microwave and millimetre wave bands  

Microsoft Academic Search

Atmospherics originating from lightning flashes have been extensively studied by radio scientists for the last several decades, with a view to assessing and predicting the interfering effect on radio communication systems. Most of the earlier studies were confined to frequencies below about 30 MHz where ionospheric propagation can be exploited. The advent of satellite communication for a global coverage has,

A. K. Sen; M. K. Das Gupta

1987-01-01

358

World atlas of satellites  

NASA Astrophysics Data System (ADS)

Features of the 17 services offered by planned or operational satellites in geostationary earth orbit (GEO) are described. The orbital inclinations, controlling organizations, and frequency bands employed by the 143 spacecraft in GEO as of 1979 are provided, together with the typical operational parameters of the 6/4 GHz transmitters and receivers. The spacecraft have nominal design lifetimes of 10-15 yr and employ FDM-FM, digital, SCPC, and video transmission techniques. Attention is given to the technology developments affecting GEO satellite system characteristics and the capacity of the GEO. Intersatellite service is characterized, as are frequency allocations and applications, and the space operation service involving frequency bands dedicated to the telemetry, tracking, and telecommand of spacecraft. Consideration is given to mobile satellite services, satellite broadcasting services, and satellite navigation, earth exploration, and positioning services. Finally, meteorological, standard frequency and time signal, and space research satellite services are explored, noting that the latter do not usually use GEO positions.

Jansky, D. M.

359

Communication satellite applications  

NASA Astrophysics Data System (ADS)

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

Pelton, Joseph N.

360

Packet Radio for Library Automation.  

ERIC Educational Resources Information Center

|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…

Brownrigg, Edwin B.; And Others

1984-01-01

361

Satellite multiple access protocols  

Microsoft Academic Search

Each one of the independent transponders in the satellite is designed to accept transmission at a selected frequency band, i.e., the uplink frequency. The satellite carries out a frequency translation to a well-defined frequency band, i.e., the downlink frequency. This scheme thus divides the total bandwidth of the satellite into well-defined channels. The advantages provided by this scheme are reduced

C. Retnadhas

1980-01-01

362

Satellites Orbiting Earth  

NSDL National Science Digital Library

In recent years, there has been a push to better understand how Earth works as a system- how land, oceans, air, and life all interact. Satellites in orbit around Earth are a fast and efficient way of gathering remotely sensed data about the planet as a whole. This animated video shows the orbital paths of the satellites in the National Aeronautics and Space Administration (NASA) Earth Observing System (EOS), a collection of satellites that work together to study Earth on a wide scale.

363

Radio Observations of Supernovae 2004dj and 2004et  

NASA Astrophysics Data System (ADS)

We present results from the on-going radio monitoring of Supernova (SN) 2004et in NGC 6946 and SN 2004dj in NGC 2403. Using the Very Large Array to monitor the supernovae at 1.3, 2, 3.6, 6 and 20 cm, we present radio light-curves of these type IIP SNe. We discuss parameterizations and modeling of this data and make predictions of the nature of the progenitor stars based on previous research. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. BCK and MTK are undergraduates at Marquette University. CJS is a Cottrell Scholar sponsored by Research Corporation. KWW is supported by the Office of Naval Research.

Kaster, B. C.; Kelley, M. T.; Panagia, N.; Sramek, R. A.; Stockdale, C. J.; Van Dyk, S. D.; Weiler, K. W.

2005-12-01

364

Corporate governance and public corruption  

Microsoft Academic Search

Corporate governance in the private sector and corruption are important for economic development and private sector development. This paper investigates how corporate governance in private-sector media companies can affect public corruption. The analytical framework, based on models of corporate governance, identifies two channels through which media ownership concentration affects corruption: an owner effect, which discourages corruption and a competition-for-control effect

Ana Cusolito

2010-01-01

365

How Satellites See  

NSDL National Science Digital Library

This lesson allows students to compare and contrast three NASA satellites: The Extreme Ultraviolet Explorer (EUVE), The Cosmic Background Explorer (COBE), and the Hubble Space Telescope (HST). The lesson includes access to data and images from these three NASA astronomy satellites, contrasting the way the sky appears in three very different electromagnetic wavelengths or colors of light. Other satellite information is included, but the focus is a simple introduction to the electromagnetic spectrum as used by the three space observatories. While participating in this activity, students will compare physical parts and orbits of each satellite and participate in hands-on experiments to begin to understand visible, infrared and ultraviolet wavelengths.

366

Direct broadcast satellite receivers  

NASA Astrophysics Data System (ADS)

The feasibility of broadcasting direct to the home from a geostationary satellite was recognized at least two decades ago and by the mid-1960s the receiver industry was already considering the implications. Attention is given to allocations and transmission parameters, broadcast satellite plans, television receiving systems, individual satellite television receiver components, and aspects of sound broadcast reception. It is concluded that satellite television broadcasting services will be introduced by a number of European countries in the next two or three years. The requirement for mass-produced equipment for individual reception of such signals has been shown to be realizable, and development of low-cost solutions is now in progress.

Freeman, K. G.

1982-03-01

367

Tools of radio astronomy  

Microsoft Academic Search

The fundamental physics of radio emission from astronomical objects and the principles of radio-telescope operation are reviewed in a textbook intended for graduate physics students. Topics examined include EM-wave propagation, wave polarization, antenna theory, filled-aperture antennas, interferometers and aperture synthesis, and receivers. Consideration is given to emission mechanisms of continuous radiation, thermal and nonthermal sources, the physics of line radiation,

Kristen Rohlfs

1986-01-01

368

Radio Hardware Theory  

Microsoft Academic Search

\\u000a The essence of this book is about learning the concepts of radio design, not just copying a recipe for success. This chapter\\u000a is all theory about how radios work. Once you have an understanding of the principles, you should be able to begin experiments\\u000a of your own, not necessarily copying a design but modifying a design to work with different

Jeff Lashley

369

The Radio JOVE Project  

NASA Astrophysics Data System (ADS)

Radio JOVE is an interactive educational activity which brings the radio sounds of Jupiter and the Sun to students, teachers, and the general public. This is accomplished through the construction of a simple radio telescope kit and the use of a real-time radio observatory on the Internet. Our website (http://radiojove.gsfc.nasa.gov/) will contain science information, instruction manuals, observing guides, and education resources for students and teachers. Our target audience is high school science classes, but subjects can be tailored to college undergraduate physics and astronomy courses or even to middle school science classes. The goals of the project are: 1) Educate people about planetary and solar radio astronomy, space physics, and the scientific method 2) Provide teachers and students with a hands-on radio astronomy exercise as a science curriculum support activity by building and using a simple radio telescope receiver/antenna kit 3) Create the first ever online radio observatory which provides real-time data for those with internet access 4) Allow interactions among participating schools by facilitating exchanges of ideas, data, and observing experiences. Our current funding will allow us to impact 100 schools by partially subsidizing their participation in the program. We expect to expand well beyond this number as publicity and general interest increase. Additional schools are welcome to fully participate, but we will not be able to subsidize their kit purchases. We hope to make a wide impact among the schools by advertising through appropriate newsletters, space grant consortia, the INSPIRE project (http://image.gsfc.nasa.gov/poetry/inspire/), electronic links, and science and education meetings. We would like to acknoledge support from the NASA/GSFC Director's Discretionary Fund, the STScI IDEAS grant program and the NASA/GSFC Space Science Data Operations Office.

Garcia, L.; Thieman, J.; Higgins, C.

1999-09-01

370

Kentucky Science and Technology Corporation  

NASA Website

The Kentucky Science and Technology Corporation (KSTC) is a private nonprofit organization committed to the advancement of science, technology, entrepreneurship, and innovative economic development in Kentucky.

371

Effects of implanted radio transmitters with percutaneous antennas on the behavior of Canada Geese  

USGS Publications Warehouse

We examined whether surgically-implanted radio transmitters with percutaneous antennas affected behavior of Lesser Canada Geese (Branta canadensis parvipes) in Anchorage, Alaska. We implanted either a 26-g VHF radio transmitter or a larger VHF radio that was the same mass (35 g) and shape as a satellite transmitter in the coelom of adult females captured during molt in 2000. A control group of females was marked with leg bands. We simultaneously observed behavior of radio-marked and control females from 4-62 d following capture. We observed no differences in the proportion of time birds in different treatments allocated among grazing, resting, comfort, walking, and alert behavior. Females in different treatments spent a similar proportion of time in the water. Implantation of radio transmitters did not affect the frequency of agonistic interactions. We conclude that coelomic radio transmitters with percutaneous antennas had minimal effects on the behavior of Canada Geese.

Hupp, J. W.; Ruhl, G. A.; Pearce, J. M.; Mulcahy, D. M.; Tomeo, M. A.

2003-01-01

372

Radio magazines and the development of broadcasting: Radio broadcast and radio news, 1922–1930  

Microsoft Academic Search

This paper explores the development of two early popular radio magazines: Radio Broadcast and Radio News. The two magazines developed along with the emerging broadcast industry during the 1920s. The historical review and content analysis of the magazines revealed that they enjoyed a great deal of success in the early 1920s by appealing to amateur radio enthusiasts. Both started as

Michael Brown

1998-01-01

373

CORPORATE ENTREPRENEURSHIP: A STRATEGIC AND STRUCTURAL PERSPECTIVE  

Microsoft Academic Search

Recently there has been a growing interest in the use of corporate entrepreneurship as a means for corporations to enhance the innovative abilities of their employees and, at the same time, increase corporate success through the creation of new corporate ventures. However, the creation of corporate activity is difficult since it involves radically changing internal organisational behaviour patterns. Researchers have

João Ferreira

2005-01-01

374

Corporate Entrepreneurship: a Strategic and Structural Perspective  

Microsoft Academic Search

Recently there has been a growing interest in the use of corporate entrepreneurship as a means for corporations to enhance the innovative abilities of their employees and, at the same time, increase corporate success through the creation of new corporate ventures. However, the creation of corporate activity is difficult since it involves radically changing internal organisational behaviour patterns. Researchers have

Joao Ferreira

2002-01-01

375

(Not) Advising Corporate Officers about Fiduciary Duties  

Microsoft Academic Search

This Article explores the intersection of an important, unresolved corporate law issue and an overlooked professional responsibility issue persistently arising in the corporate milieu. The corporate law question currently unaddressed in Delaware law is whether the fiduciary duties of corporate officers, as agents, are the same as, or different from, the fiduciary duties of corporate directors. A related question is

Lyman P. Q. Johnson; Robert V. Ricca

2007-01-01

376

The Canadian Corporate-Academic Complex  

ERIC Educational Resources Information Center

|As universities more aggressively embrace corporate values, corporate management practices, corporate labor-relations policies, and corporate money, faculty associations face troubling challenges. The new reality is particularly hostile to academic freedom, and people see that hostility in the actions of corporate funders and university…

Turk, James

2010-01-01

377

Thailand's Corporate Financing and Governance Structures  

Microsoft Academic Search

November 1998Weaknesses in corporate governance and the fragile financial structure of many corporations contributed to, and deepened Thailand's recent financial crisis. Large corporations need to reduce their vulnerability to economic shocks and improve corporate governance; smaller firms should achieve a more stable funding structure.Alba, Claessens, and Djankov assess Thailand's policy options for reducing large corporations' vulnerability to economic shocks and

Pedro Alba; Stijn Claessens; Simeon Djankov

1999-01-01

378

Multinational Corporations vs. Domestic Corporations: Financial Performance and Characteristics  

Microsoft Academic Search

The analysis in this paper is composed of two segments. First, the financial performance of a sample of multinational corporations (MNCs) is compared with that derived for a control group of domestic corporations (DMCs) using market-based performance measures. Then, the paper presents a comparison of selected financial characteristics of the firms in the two groups. The results suggest the DMCs

Allen Michel; Israel Shaked

1986-01-01

379

Corporate Governance in Germany and the German Corporate Governance Code  

Microsoft Academic Search

The term “corporate governance”, and all that it implies, is now in everyday use in Germany. This is due to the enormous changes Germany has experienced in recent years, in international business, international finance and in German industrial structures. This contribution deals with recent changes in the German system of corporate governance. After a short historical review, the major elements

Gerhard Cromme

2005-01-01

380

Legitimation in corporate discourse: Oil corporations after Deepwater Horizon  

Microsoft Academic Search

Despite growing interest in corporate discourse practices, linguists have rarely focused specifically on the discursive legitimation of institutional or corporate actors after perceived episodes of wrongdoing. This may be due to the fact that under normal conditions, legitimation may scarcely be perceptible, only reaching a significant pitch when a major crisis threatens the existence of the agents involved. Should such

Ruth Breeze

2012-01-01

381

The rise of corporate governance in corporate control research  

Microsoft Academic Search

This article has two related tasks. First, we review the articles published in this Special Issue on Corporate Control, Mergers, and Acquisitions. These articles provide new evidence on several aspects of corporate control and governance including the value and performance effects of various ownership groups, the impact of internal governance structures, the effects of regulatory changes on specific industries and

Jeffry Netter; Annette Poulsen; Mike Stegemoller

2009-01-01

382

Corporate irresponsibility and corporate social responsibility: competing realities  

Microsoft Academic Search

Purpose – Building on the work of Carroll this article attempts to unravel, explore and explain corporate social responsibility (CSR) as a theoretical construct that has implications and consequences for corporate governance in particular, and more generally for the economy, business and society. It aims to extend Carroll's work on definitional constructs by re-examining some of the theoretical frameworks that

Brian Jones; Ryan Bowd; Ralph Tench

2009-01-01

383

Corporate mission, corporate policies and business outcomes: evidence from Japan  

Microsoft Academic Search

Purpose – This study sets out to explore questions such as: “Does mission statement matter? If so, in what ways?” Using data on mission statements of 128 large Japanese firms, the paper aims to show that corporate mission has a significant impact on corporate policies that determine employment, board, and financial structures. Design\\/methodology\\/approach – The paper provides evidence that strong-mission

Shinichi Hirota; Katsuyuki Kubo; Hideaki Miyajima; Paul Hong; Young Won Park

2010-01-01

384

CORPORATE SOCIAL RESPONSIBILITY – CORPORATE BRANDING RELATIONSHIP: AN EMPIRICAL COMPARATIVE STUDY  

Microsoft Academic Search

Current academic research on the relationship of firms’ CSR activities with corporate branding typically focuses on consumers’ and shareholders’ viewpoints. This research aims to shed light on how organisational members in firms perceive to be the impact of CSR activities upon their corporate brand strategy. Using a survey administered to companies in the U.K. and Bulgaria, the author investigate, firstly,

Bistra Vassileva

2009-01-01

385

Study and development of contemporary (quantitative) theories on the motion of the Uranian major satellites  

NASA Astrophysics Data System (ADS)

The data of the satellites acquired by spacecraft-centered radio and optical observations during the Voyager 2 encountering Uranus provide the first reliable estimation of the masses of all five major satellites. Contemporary quantitative theories on the motion of the Uranian satellites have been promoted. Laskar (1986) developed the first relatively complete (semi-) analytical theory (GUST86) with its high accuracy being confirmed by some authors. After that, the contributions of the refinement on the theory should be mentioned Malhotra (1989), Lazzaro (1987, 1991), investigated the effect of the near-resonance on the secular motion of the satellites; Taylor (1998), re-determined the masses of the five major satellites by the theoretical fitting into observations through numerical integration; Christou and Murray (1997) applied a second order Laplace-Lagrange theory to the satellite system. A general survey of how the quantitative theories of motion for the Uranian satellites was set up and developed is presented in the paper.

Shen, Kai-Xian; Qiao, Rong-Chuan; Liu, Jian-Rong

2004-03-01

386

Educational Radio. Information Bulletin 21-B.  

ERIC Educational Resources Information Center

The term "Educational Radio" includes all radio stations licensed for noncommercial operation. A history of educational radio begins with the first domestic law for control of radio in general, The Radio Act of 1912. Federal Communication Commission (FCC) regulations pertaining to educational radio or "public radio" deal with channel assignments,…

Federal Communications Commission, Washington, DC.

387

Ontvanger voor Digitale Radio-Omroep Via een Satelliet (Receiver for Digital Radio Broadcasting Via Satellite).  

National Technical Information Service (NTIS)

Quadrature Phase Shift Keying (QPSK) demodulators were investigated; a differential-coherent demodulator (with delay-line) for a 20.48 Mbit/sec and 118 MHz medium frequency was developed. A modified professional coherent demodulator (With Costas-loop carr...

C. R. Degraaf

1984-01-01

388

Pluto has a satellite  

Microsoft Academic Search

A natural satellite of Pluto, tentatively designated Charon, was discovered in 1978 as a noticeable bulge on the photographic image of the planet Pluto. The orbit of the satellite is calculated to be circular, with a radius of about 20,000 km, inclination of 60 degrees and a period of 6.3867 days, equal to the period of rotation of Pluto around

G. Bodifee

1979-01-01

389

Satellites in Schools.  

ERIC Educational Resources Information Center

|Discusses the use of satellite data in physics classrooms. Describes the apparatus that can be used to collect and analyze data. Provides examples of how telemetry data transmitted by the satellite UoSAT-2 can be used not only in teaching physics, but also in geography, mathematics, and information technology. (TW)|

Underwood, C. I.; And Others

1987-01-01

390

Devising geodetic satellite orbits  

Microsoft Academic Search

In the present paper, an intermediate theory of satellite motion, developed within the framework of the problem of six fixed centers with allowance for the influence of eight zonal harmonics of the geopotential, is applied to the analysis of quasi-geosynchronous and heliosynchronous orbits of geodetic satellites. Expressions for selecting nominal parameters for such orbits are proposed.

E. L. Lukashevich

1979-01-01

391

Ionospheric Research Using Satellites.  

National Technical Information Service (NTIS)

An account is given of the analysis of satellite transmissions recorded at Nairobi, Addis Ababa and Dar es Salaam. Work has been concentrated on the latitude and diurnal variation of total electron content (satellites BE-B and Canary Bird), the latitude v...

A. N. Hunter R. F. Kelleher

1968-01-01

392

Audio direct broadcast satellites  

NASA Astrophysics Data System (ADS)

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.

Miller, J. E.

1983-05-01

393

Interkosmos laser satellite rangefinder  

Microsoft Academic Search

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

V. A. Yegorov

1978-01-01

394

Solar power satellite  

Microsoft Academic Search

A solar power satellite includes a truss structure having a plurality of independently controlled solar power modules mounted to one face of the truss structure. The solar power satellite is constructed in orbit by first forming and then assemblying component beam members to the truss structure. The solar power modules are constructed on a fabrication and assembly station movably attached

R. J. Copeland; J. D. Martin

1983-01-01

395

ESRO applications satellites  

Microsoft Academic Search

The ESRO programs and their user oriented features and international cooperation aspects are stressed. A regional communication satellite system using frequencies around 12 GHz is being set up for Europe. An experimental preoperative satellite (OTS) with 5000 telephone channels and two television programs (Eurovision) or alternatively 6000 telephone channels, also carrying telecommunication experiments will be launched early in 1977. The

C. Rosetti; J. P. Contzen

1974-01-01

396

Signals from Communications Satellites.  

ERIC Educational Resources Information Center

|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)|

Thomsen, Volker

1996-01-01

397

Modular survivable satellite support  

Microsoft Academic Search

The development of a highly mobile, survivable satellite system from the Transportable Mobile Ground Station (T\\/MGS) is proposed. The addition of advanced capabilities to the T\\/MGS such as telemetry processing equipment, and the flexibility of a modularly designed system are examined. The need to increase survivability and mobility while reducing life cycle costs is discussed. A modular survivable satellite support

R. E. Wagner

1984-01-01

398

Internet Satellite Challenges  

Microsoft Academic Search

The current extension of communications, embracing terrestrial and space domains, raises a few legit questions in terms of business model, compatibility, and sustainability. Related to Internet satellites, this paper considers the following questions: Who are the US-based major operational Internet satellite organizations? What was the ambitious plan, and why did it fail? What are the basic incompatibilities of Internet and

William W. Wu

2010-01-01

399

Jovian and Saturnian satellites  

Microsoft Academic Search

The years 1983-1987 follow mankind's epochal first spacecraft encounters with the giant planets Jupiter and Saturn. Possibly the most spectacular “discoveries” there were the diversity and level of geological activity on the satellites that circle each. And part of the excitement no doubt stemmed from rebuttal of pre-encounter preconceptions, as the satellites of the inner solar system, while fascinating, are

William B. McKinnon

1987-01-01

400

MIMO over Satellite: A Review  

Microsoft Academic Search

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,

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

2011-01-01

401

Satellite services beyond 1990  

NASA Astrophysics Data System (ADS)

The commercial use of satellite-system services is discussed in terms of the services that can complement high-speed optical cables. The services currently offered are reviewed, and advances in fiber optics are evaluated to determine potential satellite-service markets. The advantages of satellite implementations include large coverage area, network flexibility, direct connections, and both multipoint-to-point and point-to-multipoint connections. Potential applications and services listed include multipoint and multilateral videoconferencing, computer/data communications, universal personal telecommunications, Ka-band bulk data transfer, satellite news gathering, and single-band VSATs. One important conclusion of the present review is that satellite designs should be driven by market/service considerations as opposed to technology.

Mohajeri, M.; Lo, Gerald; Subaran, Frank; Siachinji, Kenneth

1992-03-01

402

Performance and uses of a refurbished 30-m former satellite communications antenna: The Georgia Tech Woodbury Research Facility  

Microsoft Academic Search

A class of large satellite communication antennas built in the 1970s for commercial purposes comprises a potential set of large antennas useful for education, research, satellite communications, or radio astronomy upon upgrade. Many of these facilities were abandoned as the advent of low-noise electronics obviated the need for such large antennas with their associated maintenance costs. Although many have sat

David R. DeBoer; Paul G. Steffes

1999-01-01

403

Dynamical Friction on Satellites  

NASA Astrophysics Data System (ADS)

Deienno et al 2011 (A&A, v.536, A57) investigated the effects of the planetary migration on the satellites of Uranus. We concluded that Uranus might have had more satellites than those observed today. However, due to the Late Heavy Bombardment (LHB) phenomenon, those satellites beyond Oberon were destabilized mostly by collisions involving themselves or with some regular ones. In this work we apply the same methodology for the Saturnian system. We found that the satellites with orbits inside Titan's orbit are immune to the LHB phenomenon. On the other hand, Hyperion, Iapetus, and even Titan, in some cases are strongly affected by the LHB, and depending on the value of Saturn's obliquity, Iapetus might not have resisted to the LHB event. We also found that, the final orbital elements of the surviving satellites differ from what we see today, mainly in inclination. While eccentricity and orbital semi-major axis can be easily damped by tides, for orbital inclinations, tidal effects are not so efficient. Thus, considering that eccentricity and orbital semi-major axis will still evolve by tides, to study the problem of the orbital inclination we consider that: according to our simulations, during the LHB event, collisions between planetesimals and satellites are a common event, causing in some cases destruction of satellites. So, we hypothesized that the material delivered by these catastrophic events could form a disc of particles around the remaining of satellites' orbits. This disc interacts with the remaining satellites and by dynamical friction phenomenon the orbital inclination can be damped. Some preliminary results have shown that, indeed, this tentative can be a viable way to damp conveniently the inclination of some satellites. Acknowledgement: FAPESP-CNPq

Deienno, Rogerio; Yokoyama, T.; Prado, A. F. B. A.

2012-10-01

404

Will Corporate Income Taxation Survive?  

Microsoft Academic Search

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

Ruud A. De Mooij

2005-01-01

405

Corporal Punishment and Child Adjustment  

ERIC Educational Resources Information Center

|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…

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

2006-01-01

406

Corporate Ownership Around the World  

Microsoft Academic Search

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

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

1999-01-01

407

The Global Corporate Governance Forum  

Microsoft Academic Search

The Global Corporate Governance Forum (GCGF) is a multidonor trust fund founded by the World Bank Group and the Organization for Economic Co-operation and Development (OECD) to promote global, regional, and local initiatives that aim improving the institutional framework and practices of corporate governance. \\

Ross Levine

408

Criminal Charges in Corporate Scandals.  

National Technical Information Service (NTIS)

Since the collapse of Enron Corp. in late 2001, there has been a series of scandals involving major U.S. corporations. Recurring elements in the scandals include improper or fraudulent accounting, self-enrichment by corporate officers, stock trading on in...

M. Jickling P. H. Janov

2004-01-01

409

Corporate governance and innovative leaders  

Microsoft Academic Search

Purpose – The purpose of this paper is to attract readers' attention to the importance of the integration of corporate governance and innovation for companies to strive further in business. The paper also attempts to illustrate how an innovation champion can exist in companies with a good corporate governance structure and fully utilize the structure, at the same time being

M. A. Musa; S. E. Ismail; S. Othman

2008-01-01

410

Corporate Governance in Financial Institutions  

Microsoft Academic Search

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

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

411

Corporal Punishment and Child Adjustment  

ERIC Educational Resources Information Center

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…

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

2006-01-01

412

Fostering Rural/Corporate Partnerships.  

ERIC Educational Resources Information Center

|Discusses how rural groups might approach corporations to forge partnerships for a variety of educational and community programs and activities. Makes specific suggestions for selecting corporations, writing the first requests for information, evaluating responses, and following up leads. Includes a section on the workings of Apple Computer's…

Vermillion, Mark

1986-01-01

413

Re-Enchanting the Corporation  

Microsoft Academic Search

This Essay begins with Max Weber’s observation that the condition of the modern world is “disenchanted” and goes on to argue that contesting the notion of disenchantment offers a promising framework for rethinking baseline issues in corporate law and corporate life more generally. After elaborating what disenchantment meant to Weber, this Essay offers two counter-observations. First, the world may not

Lyman P. Q. Johnson

2010-01-01

414

Superfine Structure of Jovian Millisecond Radio Bursts  

NASA Astrophysics Data System (ADS)

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.

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

2004-05-01

415

Digital Processing Equipment for the Space Radio Systems Facility and Its Utilization.  

National Technical Information Service (NTIS)

A description is given of the digital processing equipment used for the Space Radio Systems Facility at Aerospace Corporation. This equipment has been programmed to position the millimeter wave antenna to an overall pointing accuracy of 20 sec of arc. The...

R. N. Geddes

1964-01-01

416

64 FR 42728 - International Uranium (USA) Corporation  

Federal Register 2010, 2011, 2012, 2013

...Number 40-9048] International Uranium (USA) Corporation AGENCY: Nuclear Regulatory...a request from International Uranium (USA) Corporation that the NRC terminate all...a predecessor of International Uranium (USA) Corporation. The NRC received a...

1999-08-05

417

12 CFR 563.201 - Corporate opportunity.  

Code of Federal Regulations, 2013 CFR

... 2012-01-01 true Corporate opportunity. 563.201 Section 563.201...and Bonding § 563.201 Corporate opportunity. (a) If you are a director...must not take advantage of corporate opportunities belonging to the savings...

2013-01-01

418

12 CFR 163.201 - Corporate opportunity.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Corporate opportunity. 163.201 Section 163.201...and Bonding § 163.201 Corporate opportunity. (a) If you are a director...must not take advantage of corporate opportunities belonging to the savings...

2013-01-01

419

Regoliths of icy satellites: The coherent backscatter model  

NASA Astrophysics Data System (ADS)

The coherent backscatter model of radar scattering from icy satellites argues that most of the received power comes from radio waves that have been multiply scattered from numerous refractive index discontinuities randomly located under the surfaces of the regoliths. In a laboratory analog experiment the circular and linear polarizations were measured in light scattered from a suspension of polystyrene spheres in water illuminated by laser. Results confirm that coherent backscatter from particle media reproduces the large intensity and unusual polarizations observed in the radar data. The model implies that the regoliths of icy satellites consist of matrices of small reflective index containing imbedded scatterers separated by distances of the order of a wavelength.

Hapke, B.; Blewett, D.

1991-06-01

420

A planar wideband circularly polarized antenna for satellite communications  

Microsoft Academic Search

A planar wideband circularly polarized antenna for Ku-band satellite communications is presented. The antenna consists of an array of bow-tie antennas printed on a thin dielectric substrate that is fed through a corporate feed divider network. The array is backed by a low dielectric substrate coated with a metallized ground plane to provide one-sided radiation. This configuration is sandwiched by

D. F. Filipovic

1999-01-01

421

Land mobile communications and position fixing using satellites  

Microsoft Academic Search

In a recent series of experiments, the General Electric Corporate Research and Development Center demonstrated effective satellite-aided land mobile communications, analog and digital data relay, and automatic real-time vehicle position fixing. In one sequence of tests a station wagon was equipped with a specially designed antenna, a slightly modified commercial VHF transceiver, and a digital tone-code ranging responder that operated

AXEL F. BRISKEN; ROY E. ANDERSON; RICHARD L. FREY; JAMES R. LEWIS

1979-01-01

422

Swedish small satellites  

NASA Astrophysics Data System (ADS)

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.

Lundahl, K.; von Scheele, F.

2004-11-01

423

Iridium Satellite Signal Exploitation  

NASA Astrophysics Data System (ADS)

The Iridium Satellite constellation is unique to satellite communication networks in that it allows for transmission of data between satellites instead of relying on transmission by the bent pipe methodology. As such, this network is far more secure than other satellite communication networks, and forces interception to occur within the locale of the transmission from modem to satellite or within the locale of the downlink from the satellite other modem. The purpose of this project was to demonstrate the security weaknesses within the Iridium protocol, showing that it was possible to track one of these satellites with a high gain antenna, resulting in the ability to anticipate transmission, to acquire the location of that transmission, and to uncover the content of that transmission. This project was completed as part of the summer student program at the Southwest Research Institute. The presentation will demonstrate the thought process used in chronological order, essentially demonstrating how I achieved the result from my point of view as the summer progressed.

McDonough, Peter

2010-03-01

424

Attitude Detection Method of Nano Satellite HIT-SAT by Fluctuation of Received Signal Strength  

NASA Astrophysics Data System (ADS)

In recent years, many universities have already launched small satellite on-orbit. Attitude information is important for satellite operation. However, many nano-satellite communication systems used amateur radio by narrow bandwidth frequency segment. Therefore, down-link of attitude information is expected to require substantial time. In this paper, we propose establishment of the attitude estimation method by means of the received radio power. And, satellite attitude information being estimated from the fluctuation of the received power. Then, comparison of satellite data obtained from on-board sensors with ground experiment. One major problem in this approach is the effect of Earth's ionosphere. As the radio signal passes through the ionosphere, the polarization angle is rotated by the Faraday Effect. The detection of attitude by the radiation pattern has been assumed that inaccurate. However, we are get data the spin satellite of liner polarization antenna. As a result, we can estimate 0.12rad/s accuracy of angular velocity measurement. This method can be applied to the attitude detection of many small satellites.

Sato, Tatsuhiro; Mitsuhashi, Ryuichi; Satori, Shin; Sasaki, Issei

425

Corporate identity, corporate branding and corporate marketing - Seeing through the fog  

Microsoft Academic Search

Outlines 15 explanations for the fog which has enveloped the nascent domains of corporate identity and corporate marketing. However, the fog surrounding the area has a silver lining. This is because the fog has, unwittingly, led to the emergence of rich disciplinary, philosophical as well as “national”, schools of thought. In their composite, these approaches have the potential to form

John M. T. Balmer

2001-01-01

426

Type III solar radio burst storms observed at low frequencies  

Microsoft Academic Search

The analysis of a storm of type III solar radio bursts observed in August 1968 between 5 and 0.2 MHz by the RAE-1 satellite has yielded the storm morphology, a possible relation to meter and decameter storms, and an average exciter speed of 0.37 c between 10 and 40 R? (Fainberg and Stone, 1970a, b). A continuation of the analysis,

Joseph Fainberg; R. G. Stone

1971-01-01

427

New trends in laser satellite communications: design and limitations  

NASA Astrophysics Data System (ADS)

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 HAPs can be also involved. This work gives an overview of nowadays laser satellite communications. Particularly, it is focused on the factors causing degradation of the optical beam in the atmosphere. If an optical link passes through the atmosphere, it suffers from various influences such as attenuation due to absorption and scattering, intensity fluctuations due to atmospheric turbulence and background radiation. Furthermore, platform vibrations cause mispointing and following tracking losses. Suitable devices and used pointing and tracking system for laser satellite communications are discussed. At the end, various scenarios of the optical links and calculations of their power link budgets and limitations are designed. Implemented software is used for calculation of optical links. This work proves that the Free Space Optics (FSO) systems on mobile platforms, like satellites and HAPs are a promising solution for future communication networks.

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

2008-11-01

428

Rolling Stone Radio  

NSDL National Science Digital Library

Rolling Stone Radio is a fun and interesting site that may represent the future of Internet radio. The site provides a number of streaming audio channels that can be listened to via RealNetworks' RealPlayer G2 combined with a customized, radio-like interface to the site. Each channel features a particular genre of music, and the interface displays the artist and song title during play. The sound quality ranges from acceptable to excellent, and the sound controls and channel selectors are easy-to-use. While the site borders on the exploitative in its advertising and ability to purchase music by clicking through the interface, it does combine some of the best ideas on the Internet into a seamless entertainment package. All downloadable components of this site are free but run only on Win95/98/NT.

1999-01-01

429

Toward Global Soundings and Atmospheric Measurements for Climate and NWP Using GNSS Radio Occultation Systems  

Microsoft Academic Search

The history of observing radio occultations [RO] using a space-borne platform and an earth-based or another space-based platform to probe an intervening planetary atmosphere, i.e. to determine atmospheric profiles and characteristics, dates back to 1964 with the sounding of the atmosphere of Mars and subsequent soundings of planetary atmospheres using a radio transmitter on a satellite and the RO technique.

S. A. Mango; D. Ector; P. Wilczynski; R. A. Fulton; D. Whitely; L. Cucurull; V. Chu; W. S. Schreiner; C. Rocken; R. A. Anthes; Y. Kuo; K. Cook

2010-01-01

430

Search for X-ray emission from the radio lobes of Scorpius X-1  

Microsoft Academic Search

Images obtained with the low-energy imaging telescope on board the European X-Ray Astronomy Satellite have been searched for X-ray emission from the radio lobes of Sco X-1. After the scattered photons from the image of the central X-ray source in Sco X-1 are taken into account, no significant additional X-ray flux from the radio lobes can be detected above the

Barry Geldzahler; Paul Hertz

1987-01-01

431

EMC of ground-based and space radio services - Criteria, conditions, and calculations  

NASA Astrophysics Data System (ADS)

Attention in this monograph is first given to the types of radio signals employed in ground-based and space radio services; their energy spectra are examined, and a description is given of methods for calculating interference for different combinations of signal and interference. Conditions for the satisfaction of EMC criteria are described, and the calculation of the required angular distribution of geostationary satellites is discussed. The effective utilization of the geostationary orbit and its potential capacity is considered.

Borodich, Sergei V.

432

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.

433

JOI reaffirms satellite plan  

NASA Astrophysics Data System (ADS)

A recent report by the Satellite Planning Committee of Joint Oceanographic Institutions, Inc. (JOI), Washington, D.C., underscored the need for the four oceanographic satellite missions that have been proposed for the next decade to be carried out as planned and firmly on schedule. In reaffirming the need for the missions, the committee said that many important types of long-term global data auoui ihe oceans can be gathered only by research satellites. The potential benefits to vital national activities such as trade, fisheries, national defense, and waste disposal will be well worth the missions' cost, they added.

Katzoff, Judith A.

434

Joint polar satellite system  

NASA Astrophysics Data System (ADS)

The Joint Polar Satellite System (JPSS) is a joint NOAA/NASA mission comprised of a series of polar orbiting weather and climate monitoring satellites which will fly in a sun-synchronous orbit, with a 1330 equatorial crossing time. JPSS resulted from the decision to reconstitute the National Polar-orbiting Operational Environmental Satellite System (NPOESS) into two separate programs, one to be run by the Department of Defense (DOD) and the other by NOAA. This decision was reached in early 2010, after numerous development issues caused a series of unacceptable delays in launching the NPOESS system.

Trenkle, Timothy; Driggers, Phillip

2011-10-01

435

Basics of Radio Astronomy  

NSDL National Science Digital Library

This online workbook is used for training teachers and volunteers who wish to operate the Goldstone-Apple Valley Radio Telescope. The students in this district operate the telescope from the Apple Valley location. Also, students and teachers across the country can register to operate the telescope from their own classrooms. This workbook can also be used as a resource for information on how radio telescopes work, the fundamentals of the electromagnetic spectrum, thermal and non-thermal radiation, 21-cm hydrogen line, Kirchhoff's laws of spectral analysis, the Doppler effect, coordinate systems, and the SETI project.

Fisher, Diane

2004-07-16

436

Isla Earth Radio Series  

NSDL National Science Digital Library

This radio series explores environmental issues of local, national, and global importance, with the intent to increase ecological awareness, deepen understanding, and encourage environmentally sustainable choices. Topics include alternative fuels, endangered species, energy conservation, wetlands, and similar issues. Each program is accompanied by a written transcript and links to additional information from other web sites. Other materials include image galleries, puzzles and games with environmental themes, and the e-Digest--a series of written features on environmental topics. There is also information on the show's sponsor and information for radio stations that wish to carry the program.

437

Radio protection zone evaluation at the Dominion Radio Astrophysical Observatory  

Microsoft Academic Search

Increasing use of the radio spectrum by licensed and unlicensed devices, together with the encroachment of housing developments are an issue facing many radio observatories, including the Dominion Radio Astrophysical Observatory (DRAO), located near Penticton in Southern British Columbia. A joint study by Industry Canada (Canada's national spectrum manager), and the National Research Council (Operator of DRAO) is currently in

Ken Tapping

2008-01-01

438

The impact of cognitive radio on radio astronomy  

Microsoft Academic Search

The introduction of new communication techniques requires an increase in the efficiency of spectrum usage. Cognitive radio is one of the new techniques that fosters spectrum efficiency by using unoccupied frequency spectrum for communications. However, cognitive radio will increase the transmission power density and cause an increasing level of Radio Frequency Interference (RFI), which may impact other services and particularly

M. J. Bentum; A. J. Boonstra; W. A. Baan

2010-01-01

439

75 FR 10439 - Cognitive Radio Technologies and Software Defined Radios  

Federal Register 2010, 2011, 2012, 2013

...stated in the MO&O prohibit radio manufacturers and software developers...circumvented to allow operation of a radio in a manner that violates the...Commission would encourage such work by industry. The Commission's...implementing software defined radio security features. The...

2010-03-08

440

MEMOS - Mars Environment Monitoring Satellite  

NASA Astrophysics Data System (ADS)

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

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

2007-08-01

441

47 CFR 32.2231 - Radio systems.  

Code of Federal Regulations, 2010 CFR

...original cost of radio equipment used to provide radio communication channels. Radio equipment is that equipment which is used for...reception, modulation, and demodulation of radio waves in free space over which communication...

2009-10-01

442

47 CFR 32.2231 - Radio systems.  

Code of Federal Regulations, 2010 CFR

...original cost of radio equipment used to provide radio communication channels. Radio equipment is that equipment which is used for...reception, modulation, and demodulation of radio waves in free space over which communication...

2010-10-01

443

Advanced Satellite Communication System.  

National Technical Information Service (NTIS)

The objective of this research program was to develop an innovative advanced satellite receiver/demodulator utilizing surface acoustic wave (SAW) chirp transform processor and coherent BPSK demodulation. The algorithm of this SAW chirp Fourier transformer...

E. J. Staples S. Lie

1992-01-01

444

Aiming a Satellite Dish.  

ERIC Educational Resources Information Center

Develops a pair of equations for calculating the elevation and azimuth angles for the various satellites. Uses 3-dimensional vector difference calculations. Provides a practical example, figures, and table. (YP)

Zebrowski, Ernest, Jr.

1988-01-01

445

Commercial Satellite Leased Capacity.  

National Technical Information Service (NTIS)

This report is the fourth in a series resulting from our audit, 'Communications Capability Within DoD to Support Two Major Regional Conflicts Nearly Simultaneously'. This report discusses the management, procurement, and usage of commercial satellite syst...

1999-01-01

446

NASA: Satellite Tracking  

NSDL National Science Digital Library

While NASA has offered a number of fine sites about their research for the general public over the years, this particular site may be one of their best. With a minimum of fuss, visitors can use several of the online tracking applications offered here to locate hundreds of satellites and other such large objects in space. A good way to start a visit to this site is by taking a look at the J-Track 2.5 section, as it offers a quick way to find out the current location of the Space Station and the Chandra X-Ray Observatory. Additionally, visitors can also locate weather satellites using this application. The Live 3D Java Tracking Display here allows visitors to monitor close to 700 satellites that are in motion around the earth. Finally, visitors can also use a handy application offered here that allows them to determine which satellites might be seen from their location in the night sky.

2005-01-01

447

Satellite Power System (SPS).  

National Technical Information Service (NTIS)

Potential organizational options for a solar power satellite system (SPS) were investigated. Selection and evaluation criteria were determined to include timeliness, reliability, and adequacy to contribute meaningfully to the U.S. supply; political feasib...

H. G. Edler

1978-01-01

448

Civil satellite navigation systems  

NASA Astrophysics Data System (ADS)

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.

Blanchard, Walter F.

1991-07-01

449

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.

450

Overview of commercial satellite communications  

NASA Astrophysics Data System (ADS)

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

Beakley, G. W.

1984-07-01

451

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.

452

Launching a Satellite  

NSDL National Science Digital Library

Isaac NewtonÂs 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.

Consortium, The C.

2011-12-11

453

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...

454

Data communications via satellite  

NASA Astrophysics Data System (ADS)

The Americom satellite communications system is described with respect to data service offerings that range from teletype traffic to wideband services in excess of 60 Mbps. Present wideband services are discussed, along with voice bandwidth data, satellite channel delay, bit rate variations, and the commercial wideband data system known as 56 Plus. Attention is given to the forward error correction, TDMA transmission, terminal operation, and piggyback data on TV distribution.

Langhans, R. A.; Mitchell, T. H.

1980-12-01

455

Satellite clocks characterization and monitoring for global navigation satellite systems  

Microsoft Academic Search

In Global Navigation Satellite Systems (GNSS) the user’s position is determined measuring the time of flight of the signals broadcast from satellites, which is proportional to the distance between the user and each satellite of the constellation. Time and frequency metrology has an essential role in satellite navigation systems: since a distance can be measured from a time, any error

A. Cernigliaro; I. Sesia

2011-01-01

456

Corporate Governance and Corporate Social Responsibility in Profit and in Non-ProfitOrganizations  

Microsoft Academic Search

Corporate Governance governs corporations. To discuss the law and economics of corporations, their performance on the market\\u000a and management control by legislation and government, is to discuss Corporate Governance. Now, Corporate Governance is being\\u000a challenged by a new concept to conceive the role of corporations in the world and to control their managers: this is the concept\\u000a of Corporate Social

Claus Ott

2009-01-01

457

Forecasting scintillations, the CNOFS satellite challenge  

NASA Astrophysics Data System (ADS)

This paper describes the science issues associated with the Communication / Navigation Outage Forecasting System (C/NOFS) Mission of the Air Force Research Laboratory. The primary purpose of C/NOFS is to forecast ionospheric irregularities that adversely impact communication and navigation systems. A satellite, scheduled for launch in January 2004 into a low inclination (13^o), elliptical (˜400 × 700 km) orbit, is the main component of the C/NOFS Mission. Complementary ground-based measurements are also part of the Mission. Difficulties in predicting the presence of scintillation-producing irregularities may be organized into three categories: (1) understand physical processes active in the background ionosphere and thermosphere, in order to nowcast and forecast the equatorial ionosphere; (2) identify mechanisms that trigger or quench the plasma irregularities; and (3) determine how irregularity spectra evolve. C/NOFS is the first satellite solely dedicated to forecasting ionospheric irregularities and radio wave scintillations. Its sensors will measure the following parameters: ambient and fluctuating electron densities; ion and electron temperatures; AC and DC electric fields; magnetic fields; neutral winds; ionospheric scintillations; and electron content along the lines of sight between the C/NOFS and GPS satellites. Forecasting will be based on both ground and space data. Significant international participation in pursuing C/NOFS science goals is desired and anticipated.

de La Beaujardiere, O.; Retterer, J.; Groves, K.; Burke, W.; Rich, F.; Basu, B.; Decker, D.; Jeong, L.

2003-04-01

458

Satellite-aided mobile communications limited operational test in the trucking industry  

NASA Astrophysics Data System (ADS)

An experiment with NASA's ATS-6 satellite, that demonstrates the practicality of satellite-aided land mobile communications is described. Satellite communications equipment for the experiment was designed so that it would be no more expensive, when mass produced, than conventional two-way mobile radio equipment. It embodied the operational features and convenience of present day mobile radios. Vehicle antennas 75 cm tall and 2 cm in diameter provided good commercial quality signals to and from trucks and jeeps. Operational applicability and usage data were gathered by installing the radio equipment in five long-haul tractor-trailer trucks and two Air Force search and rescue jeeps. Channel occupancy rates are reported. Air Force personnel found the satellite radio system extremely valuable in their search and rescue mission during maneuvers and actual rescue operations. Propagation data is subjectively analyzed and over 4 hours of random data is categorized and graded as to signal quality on a second by second basis. Trends in different topographic regions are reported. An overall communications reliability of 93% was observed despite low satellite elevation angles ranging from 9 to 24 degrees.

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

1980-07-01

459

Ham Radio is Mir Magic.  

ERIC Educational Resources Information Center

Presents a classroom activity in which students communicated with U.S. and Russian astronauts via ham radio while they were in orbit on the space station Mir. Gives suggestions for other ham radio classroom activities as well as names of organizations, publications, and grant programs that teachers can access to help in bring ham radio into their…

Evans, Gary

1997-01-01

460

Radio: Your Publics Are Listening!  

ERIC Educational Resources Information Center

|The purpose of this booklet is to provide school board members, administrators, teachers, and others interested in education with an understanding of radio, how it works, and how school systems can take advantage of the communications possibilities offered by radio. After providing background information on radio as a mass communications medium…

Marx, Gary

461

Earthwatch Radio: Rock Bottom  

NSDL National Science Digital Library

In this radio broadcast, a college geology department chairman explains that very few students currently entering college are choosing to study geology. He points out that most high schools teach little or no geology, many recent news stories involve geological issues, and that, for those who do study it, the job outlook is bright. The clip is 2 minutes in length.

Pomplun, Steve

2010-08-24

462

Highway advisory radio  

Microsoft Academic Search

In 1977, two years after its initial Notice of Proposed Rule Making in Docket 20509, the Federal Communications Commission (FCC) authorized the establishment of travelers' information stations (TIS) in the Local Government Radio Service, Part 90 of the FCC Rules and Regulations. Stations may he authorized on either 530 kHz or 1610 kHz for the purpose of providing useful noncommercial

H. C. Turnage

1980-01-01

463

Transmission System Radio Influence  

Microsoft Academic Search

An economic overhead electric power transmission system which produces no radio influence is beyond the present state of the art. However, sound engineering and attention to relevant aspects of design can produce a system having an acceptable (or tolerable) influence level. Such criteria as have been proved by research or experience together with accepted practices in instrumentation and measurement of

1965-01-01

464

Cognitive MIMO radio  

Microsoft Academic Search

Radio regulatory bodies are recognizing that the rigid spectrum assignment granting exclusive use to licensed services is highly inefficient, due to the high variability of the traffic statistics across time, space, and frequency. Recent Federal Communications Commission (FCC) measurements show that, in fact, the spectrum usage is typically concentrated over certain portions of the spectrum, while a significant amount of

Gesualdo Scutari; Daniel P. Palomar; Sergio Barbarossa

2008-01-01

465

Japanese Radio Exercises. Revised.  

ERIC Educational Resources Information Center

|This unit focuses on Japanese radio exercises which became popular in Japan just after World War II and are still used among students and workers in companies to help raise morale and form group unity. The exercises reflect the general role of exercise in Japanese culture--to serve as a symbol of unity and cooperation among the Japanese, as well…

Young, Jocelyn

466

Nobeyama Radio Observatory  

NASA Astrophysics Data System (ADS)

Nobeyama Radio Observatory has telescopes at millimeter and submillimeter wavelengths. It was established in 1982 as an observatory of Tokyo Astronomical Observatory (NATIONAL ASTRONOMICAL OBSERVATORY, JAPAN since 1987), and operates the 45 m telescope, Nobeyama Millimeter Array, and Radioheliograph. High-resolution images of star forming regions and molecular clouds have revealed many aspects of...

Murdin, P.

2000-11-01

467

Seasonal and annual movements of radio-collared polar bears ( Ursus maritimus) in northeast Greenland  

Microsoft Academic Search

The distribution and movements of polar bears (Ursus maritimus) in the Northeast Water (NEW) area (NE Greenland) were studied from 28 May 1993 to 31 May 1995, using satellite telemetry. Between 28 May and 17 June 1993 satellite-linked radio transmitters were attached to eight adult females in the NEW area between approximately 79° and approximately 80°30?N. By 31 May 1995

E. W. Born; Ø. Wiig; J. Thomassen

1997-01-01

468

The LOFAR radio environment  

NASA Astrophysics Data System (ADS)

Aims: This paper discusses the spectral occupancy for performing radio astronomy with the Low-Frequency Array (LOFAR), with a focus on imaging observations. Methods: We have analysed the radio-frequency interference (RFI) situation in two 24-h surveys with Dutch LOFAR stations, covering 30-78 MHz with low-band antennas and 115-163 MHz with high-band antennas. This is a subset of the full frequency range of LOFAR. The surveys have been observed with a 0.76 kHz/1 s resolution. Results: We measured the RFI occupancy in the low and high frequency sets to be 1.8% and 3.2% respectively. These values are found to be representative values for the LOFAR radio environment. Between day and night, there is no significant difference in the radio environment. We find that lowering the current observational time and frequency resolutions of LOFAR results in a slight loss of flagging accuracy. At LOFAR's nominal resolution of 0.76 kHz and 1 s, the false-positives rate is about 0.5%. This rate increases approximately linearly when decreasing the data frequency resolution. Conclusions: Currently, by using an automated RFI detection strategy, the LOFAR radio environment poses no perceivable problems for sensitive observing. It remains to be seen if this is still true for very deep observations that integrate over tens of nights, but the situation looks promising. Reasons for the low impact of RFI are the high spectral and time resolution of LOFAR; accurate detection methods; strong filters and high receiver linearity; and the proximity of the antennas to the ground. We discuss some strategies that can be used once low-level RFI starts to become apparent. It is important that the frequency range of LOFAR remains free of broadband interference, such as DAB stations and windmills.

Offringa, A. R.; de Bruyn, A. G.; Zaroubi, S.; van Diepen, G.; Martinez-Ruby, O.; Labropoulos, P.; Brentjens, M. A.; Ciardi, B.; Daiboo, S.; Harker, G.; Jeli?, V.; Kazemi, S.; Koopmans, L. V. E.; Mellema, G.; Pandey, V. N.; Pizzo, R. F.; Schaye, J.; Vedantham, H.; Veligatla, V.; Wijnholds, S. J.; Yatawatta, S.; Zarka, P.; Alexov, A.; Anderson, J.; Asgekar, A.; Avruch, M.; Beck, R.; Bell, M.; Bell, M. R.; Bentum, M.; Bernardi, G.; Best, P.; Birzan, L.; Bonafede, A.; Breitling, F.; Broderick, J. W.; Brüggen, M.; Butcher, H.; Conway, J.; de Vos, M.; Dettmar, R. J.; Eisloeffel, J.; Falcke, H.; Fender, R.; Frieswijk, W.; Gerbers, M.; Griessmeier, J. M.; Gunst, A. W.; Hassall, T. E.; Heald, G.; Hessels, J.; Hoeft, M.; Horneffer, A.; Karastergiou, A.; Kondratiev, V.; Koopman, Y.; Kuniyoshi, M.; Kuper, G.; Maat, P.; Mann, G.; McKean, J.; Meulman, H.; Mevius, M.; Mol, J. D.; Nijboer, R.; Noordam, J.; Norden, M.; Paas, H.; Pandey, M.; Pizzo, R.; Polatidis, A.; Rafferty, D.; Rawlings, S.; Reich, W.; Röttgering, H. J. A.; Schoenmakers, A. P.; Sluman, J.; Smirnov, O.; Sobey, C.; Stappers, B.; Steinmetz, M.; Swinbank, J.; Tagger, M.; Tang, Y.; Tasse, C.; van Ardenne, A.; van Cappellen, W.; van Duin, A. P.; van Haarlem, M.; van Leeuwen, J.; van Weeren, R. J.; Vermeulen, R.; Vocks, C.; Wijers, R. A. M. J.; Wise, M.; Wucknitz, O.

2013-01-01

469

The radio pulsar Geminga  

NASA Astrophysics Data System (ADS)

We report the results of our search for pulsed radio emission from Geminga carried out in 1992, 1993 and 1996-1997 at 102.5 MHz using the BSA radiotelescope of the Pushchino Radioastronomy Observatory. The Geminga radio pulsar (PSR J0633+1746) was detected in all three observation periods. With the best signal to noise ratio Geminga was detected in records taken in 1993, when the maximum passband of the radiotelescope was used for the searches. The main criterion for radio pulsar detection was the presence of records containing the dominant spectral line at the rotation frequency of the pulsar ? = 4.22 Hz in the amplitude spectra. The method of averaging the amplitude spectra, obtained for many days in February-June 1993, was used for the determination of the mean flux density of the Geminga radio emission at 102.5 MHz.We report the main parameters of the pulsar PSR J0633 + 1746, obtained from our observations. The mean flux S102 = 8(-2+3)mJy. The average pulse profile is very wide and has a shape like in X-rays (Halpern and Holt, 1992 [Natur, 357, 222]). The profile width on the 0.5 level W0.5 ? 120 ms, i.e. about 180°. The dispersion measure DM = 3.2±0.3 pc · cm-3. A timing analysis, which was performed for the best profiles, obtained from 1992 to 1997, yields values for the period P and derivative P, which are, within error limits, in agreement with the data published by Mayer-Hasselwander et al. (1994)[ApJ, 421, 276]. We discuss possible reasons for the extremely low radio luminosity of the Geminga pulsar.

Shitov, Yu. P.; Pugachev, V. D.

1998-03-01

470

Overview of commercial satellite communications  

Microsoft Academic Search

A brief history of communications satellites is presented, taking into account the launching of Sputnik 1 in October 1957, the Explorer 1 in January of 1958, the launch of the Score as the world's first active communications satellite in December 1958, the Communications Satellite Act in 1962, and the launch of 'Early Bird' in 1964. The Intelsat satellites are considered

G. W. Beakley

1984-01-01

471

Direct Broadcasting Satellites in Japan.  

ERIC Educational Resources Information Center

|The development and use of broadcasting satellites in Japan are discussed in this paper. The paper describes the medium-scale experimental broadcasting satellite, YURI, launched by NASA in 1978, and reports that experiments with YURI in the areas of basic technologies in the broadcasting satellite system, experiments on satellite control…

Maeda, Jiro

472

Corporate environmental violence and racism  

Microsoft Academic Search

Drawing upon a social justice framework, this analysis expands and integrates issues relating to corporate violence and environmental\\u000a justice to investigate the spatial distribution of chemical accidents across census tracts in Hillsborough County, Florida.\\u000a To test the hypothesis that corporate environmental violence (CEV) is more likely to impact blacks and Hispanics, data from\\u000a the 1990 census was combined with chemical

Paul Stretesky; Michael J. Lynch

1998-01-01

473

Convergence of corporate governance systems  

Microsoft Academic Search

Differentiates market (e.g. USA) from group-based (e.g. Germany) corporate governance systems, traces their evolution and asks whether they are converging. Puts forward a theoretical convergence model based on the belief that agency problems can best be solved by specific corporate control mechanisms, recognizing that it would demand more changes from group-based than from market systems. Examines current trends for both

Guido Carati; Alireza Tourani Rad

2000-01-01

474

Corporate Yoga and Its Implications  

Microsoft Academic Search

\\u000a Yoga is being practiced as a complete means of total health and human excellence for time immemorial. So attraction towards\\u000a Yoga has been highly increased in corporate world, especially in developed countries. Merely US invests $ 5.7 billion dollar\\u000a per year for yoga classes and products [1]. Large corporations of the world like MICROSOFT, IBM, HBO, The White House, New

Rudra Bhandari; Balkrishna Acharya; V. K. Katiyar

475

Corporate governance and stakeholder conflict  

Microsoft Academic Search

The stakeholder management literature is dominated by the ‘shareholder value’ and ‘inclusive stakeholder’ views of the corporation.\\u000a Each views the governance problem in terms of inter-functional conflicts between stakeholder groups, such as between investors and managers or managers and employees, and rests on the\\u000a assumption of an idealized corporate structure characterized by the separation of ownership from management. Our review

Michael Carney; Eric Gedajlovic; Sujit Sur

2011-01-01

476

An Overview of Cassini Radio Science  

NASA Astrophysics Data System (ADS)

The Cassini spacecraft, which has been in orbit about Saturn for over a year, is the first Radio Science platform to provide three downlink frequencies. In addition to the X-band telemetry link (3,56 cm w.l.), two other frequencies, S-band (13.04 cm), and Ka-band (0.94 cm) are available. This, plus the high SNR (>50 dBHz at X-band) afforded by the 4 m diameter s/c high gain antenna in combination with the excellent low noise receivers of the DSN, as well as overall system stabilities of 1 x 10-13 when referenced to the on-board ultra-stable oscillator (USO) in one-way operation, and 1 x 10-15 for a two-way link, make Cassini an unprecedented instrument of radio science. In addition to Gravitational Wave Search and Solar Conjunction experiments conducted during the cruise phase, the orbital tour phase of the mission has as its main radio science objectives: a) determination of the masses and gravity fields of Saturn's icy satellites, Titan, and Saturn through two-way tracking during fly-bys. To date, the masses of Phoebe, Iapetus, Dione and Enceladus have been measured, and will be reported here. b) Measurement of the structure and other properties of Saturn's rings through three-band occultation. Several near-diametric occultations at a high ring opening angle have been completed, and the results will be presented here. c) Measurement of the vertical structure of the atmosphere and ionosphere of Saturn. The same series of occultations have provided nearly equatorial occultations, and the results on the atmosphere structure, the ionosphere, and the abundances of microwave-absorbing gases in Saturn's atmosphere will be described here. In the remaining years of the Cassini mission, these results will be expanded to include the atmosphere, ionosphere, surface, and gravity field of Titan, the gravity field and masses of Saturn and the remaining icy satellites, and the completion of the Saturn objectives described above. The Cassini Radio Science Team wishes to express its gratitude to the personnel of the DSN, whose contributions have made our results possible.

Kliore, A.; Rappaport, N.; Anabtawi, A.; Asmar, S.; Armstrong, J.; Barbinis, E.; Goltz, G.; Johnston, D.; Fleischman, D.; Rochblatt, D.; Anderson, J.; Marouf, E.; Wong, K.; Thomson, F.; Flasar, F. M.; Schinder, P.; French, R.; McGhee, C.; Mohammed, P.; Steffes, P.; Nagy, A.; Iess, L.; Tortora, P.; Ambrosini, R.; Flamini, E.

2005-08-01

477

Search for X-ray emission from the radio lobes of Scorpius X-1  

SciTech Connect

Images obtained with the low-energy imaging telescope on board the European X-Ray Astronomy Satellite have been searched for X-ray emission from the radio lobes of Sco X-1. After the scattered photons from the image of the central X-ray source in Sco X-1 are taken into account, no significant additional X-ray flux from the radio lobes can be detected above the background. The 3 sigma upper limit is less than 0.7 micro-Jy for the northeast radio lobe and less than 1.0 micro-J for the southwest radio lobe. This eliminates the embedded source model of Kundt and Gopal-Krishna as a viable model of the radio emission. These limits are three orders of magnitude too high to constrain models of synchrotron or inverse Compton X-ray emission. 22 references.

Geldzahler, B.; Hertz, P.

1987-11-01

478

Corporate Governance in China: a Step Forward  

Microsoft Academic Search

AbstractRecently, the presumed benefits of corporate governance have become one of the most contentious issues especially for emerging markets in Asia where institutional settings are quite different from other parts of the world. Using an internationally accepted benchmark (OECD's Principles of Corporate Governance, OECD, 2004), this study evaluates the progress of corporate governance practice of Chinese listed companies. A corporate

Yan-Leung Cheung; Ping Jiang; Piman Limpaphayom; Tong Lu

2010-01-01

479

Study on Corporate Hereditary Central Dogma  

Microsoft Academic Search

Based on analyzing the central dogma of biology, this paper raises hypothesis, using the analogism method to set up the corporate hereditary central dogma. It analyzes the differences between the Corporate hereditary central dogma and the central dogma of biology, which explains the significance of research on Corporate hereditary central dogma; it discusses the meanings of all factors of Corporate

Li Xianbai

2010-01-01

480

The Corporation and the Local Community  

Microsoft Academic Search

The corporation and the local community repre sent sometimes conflicting ends for members of the corporate hierarchy. There is a citizenship of the corporation and a citizenship of the local territorial community that may and do conflict. The corporation offices constitute many of the top status positions in the local community; the behavior of cor porate managers influences that of

Norton E. Long

1962-01-01

481

Risk Management, Real Options, Corporate Social Responsibility  

Microsoft Academic Search

The relationship of corporate social responsibility to risk management has been treated sporadically in the business society literature. Using real options theory, I develop the notion of corporate social responsibility as a real option its implications for risk management. Real options theory allows for a strategic view of corporate social responsibility. Specifically, real options theory suggests that corporate social responsibility

Bryan W. Husted

2005-01-01

482

Corporal Punishment: Legalities, Realities, and Implications.  

ERIC Educational Resources Information Center

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

Hinchey, Patricia H.

2003-01-01

483

An introduction to satellite communications  

NASA Astrophysics Data System (ADS)

An expository treatment of the principles and practice of satellite communications is presented. The development of communications satellite services is described, and the evolution of satellites and earth stations to meet changing requirements is reviewed. The physics and geometry of the geostationary orbit and the construction and operation of satellites and launch vehicles are addressed. The essential factors governing the quality of speech, data, and television signals received via satellite are analyzed. Special attention is given to growth areas in satellite communications (including analog television transmission); digital methods of transmission of voice and data; the use of satellites for maritime, aeronautical, and land-mobile communications; and very-small-aperture terminals.

Dalgleish, Don I.

484

Using GPS-GLONASS-GALILEO data and IRI modeling for ionospheric calibration of radio telescopes and radio interferometers  

NASA Astrophysics Data System (ADS)

VHF and HF radio signals are widely used to observe the Sun and pulsars. Nowadays, large low-frequency radio astronomical arrays (LOFAR, 30-240 MHz; MIRA, 80-300 MHz) are being constructed to record radiation of pulsars at the maximum distance. registration of the solar radio emission intensity at fixed frequencies and in the spectral VHF band is very important along with other methods of monitoring of coronal mass ejections. Interpreting radio astronomical data is known to be necessary to take into account possible distortions of these signals in the Earth ionosphere. However, in contrast to modern navigation systems (Global Position System (GPS), GLObal NAvigation Satellite System (GLONASS), GALILEO), in which a very accurate reconstruction of ionosphere parameters is a built-in function, in present-day radio astronomy a retrieve of ionosphere transfer characteristics has not been appropriately worked out. This collides with increasing requirements to accuracy of the analysis of a radio emission amplitude profile and to the angular and polarizing resolution of radio telescopes of new generation (LOFAR, SKA, etc.). We have developed a method and software to calculate the ionosphere rotation measure (RM) and dispersion measure (DM). We used the ionosphere model IRI-2001, magnetic field model IGRF-10, and the ionosphere total electron content values obtained from GPS measurements. The obtained values of DM and RM were recalculated into characteristics of the phase delay, Faraday amplitude modulation, and polarization changes. We calculated ones for different levels of geomagnetic activity as well as different angular positions of radio sources. Our main idea is to use a signal of navigation satellites (GPS, GLONASS, GALILEO) as a testing signal from a "reference" source located at minimal angle distance from a source studied. Our project allows development of methods and systems of ADAPTIVE RADIO ASTRONOMY, adaptive to the non-uniform and non-stationary ionosphere, by analogy with known systems of adaptive optics intended to adapt optical telescopes to varying conditions of the optically non-uniform and non-stationary troposphere.

Afraimovich, E. L.; Yasukevich, Yu. V.

2008-12-01

485

Satellite Applications for Public Service: Project Summaries.  

ERIC Educational Resources Information Center

Summaries of 18 different projects involving the use of satellite communications are presented in this report, including PEACESAT Education and Communication Experiments, USP Network Satellite Communication Project, Project Satellite, Satellite Instructional Television Experiment (SITE), Appalachian Education Satellite Program, Alaska Education…

Lauffer, Sandra; And Others

486

Satellite Applications for Public Service: Project Summaries.  

ERIC Educational Resources Information Center

|Summaries of 18 different projects involving the use of satellite communications are presented in this report, including PEACESAT Education and Communication Experiments, USP Network Satellite Communication Project, Project Satellite, Satellite Instructional Television Experiment (SITE), Appalachian Education Satellite Program, Alaska Education…

Lauffer, Sandra; And Others

487

The Relationship between Corporate Governance and Corporate Performance in China's Civilian-Owned Listed Enterprise  

Microsoft Academic Search

This paper examines the relationship between corporate governance and corporate performance. An overall set of measures are constructed to evaluate the practice of corporate governance in Chinapsilas civilian-owned listed enterprises. Factor analysis is introduced to construct a comprehensive performance variable. The result demonstrates better corporate governance mechanism is not associated with higher corporate performance in Chinapsilas civilian-owned listed enterprises. Such

Bo Zhang; Tian Lei

2009-01-01

488

Corporate profits and social responsibility: “Subsidization” of corporate income under charitable giving tax laws  

Microsoft Academic Search

Private U.S. corporations donated approximately $6 billion to nonprofit organizations in 1994. Corporations may donate money both directly to charities and indirectly through a corporate-sponsored foundation. Tax and financial advantages, as well as differences in corporate image, arise due to policy differences in the treatment of certain gifts. This paper presents a new model of corporate giving, and examines the

Natalie J. Webb

1996-01-01

489

Corporate Identity and Corporate Reputation in Silicon Valley: Case Studies in Public Relations and Integrated Communications  

Microsoft Academic Search

This two-case study of high-tech firms in Silicon Valley, near San Jose, California, explored how and why corporate identity principles were used in establishing a model campaign plan for these companies. In this process, it was necessary to establish a clearer relationship among the terms, corporate identity, corporate image, corporate branding, and corporate reputation from the organizational, advertising and public

Kenneth D. Plowman; Satina Chiu

2007-01-01

490

International communications via satellite  

NASA Astrophysics Data System (ADS)

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

McLucas, J. L.

491

Satellite-induced electron acceleration and related auroras  

NASA Astrophysics Data System (ADS)

Satellite-induced auroral emissions are known since decades, in particular those associated with the interaction of Io with the Jovian ionosphere. These emissions range from low frequency radio to UV. Flyby of Io allowed to better understand the power generation close to the satellite, and showed the existence of electron beams accelerated at high latitude. We will present a study of the power transfer between the local interaction at Io and the electron accelerated close to Jupiter. It shows that Alfvén acceleration can explain the morphology and brightness of the Io-related auroraeand the observed accelerated electrons in Io's wake. The study is extended to the Europa, Ganymede and Enceladus for which auroral emissions have been observed, as well as to Callisto and to the principal inner satellites of Saturn.

Hess, S. L. G.; Delamere, P. A.; Bonfond, B.; Dols, V.

2012-09-01

492

A new phase for NASA's communications satellite program  

NASA Astrophysics Data System (ADS)

NASA's research in communications satellite technology is discussed, including orbit-efficient techniques and applications by the commercial sector. Attention is given to expanding the capacities of the C-band (6-4 GHz) and the Ku-band (14-11 GHz), opening the Ka-band (30/20 GHz), broadly applied 're-use' of the spectrum, and developing multibeam spacecraft antennas with on-board switching. Increasing wideband services in video, high-speed data, and voice trunking is considered, as are narrow-band systems that may be used for data collection or public safety, with possible expansion to a thin-route satellite system. In particular, communication for medical, disaster, or search-and-rescue emergencies may be met by the integration of a satellite service with land mobile communications via terrestrial radio links. Also considered is a large geostationary platform providing electrical power, thermal rejection, and orbital station-keeping for many communications payloads.

Dement, D. K.

1980-01-01

493

Satellite Antenna Pointing Procedure Driven by the Ground Service Quality  

NASA Astrophysics Data System (ADS)

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.

Yasui, Yoshitsugu

494

Satellite failures revisited  

NASA Astrophysics Data System (ADS)

In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.

Balcerak, Ernie

2012-12-01

495

How Satellites See  

NSDL National Science Digital Library

This classroom project will compare and contrast three NASA satellites: The Extreme Ultraviolet Explorer (EUVE), The Cosmic Background Explorer (COBE), and the Hubble Space Telescope (HST). The lesson includes access to data and images from these three satellites, contrasting the way the sky appears in three very different electromagnetic wavelengths or colors of light. Other satellite information is included, but the focus of the project is a simple introduction to the electromagnetic spectrum as used by the three space observatories. The site provides background information, a list of materials and objectives as well as required data, illustrations, and images. A detailed procedure is followed by ideas for assessment, extensions and homework assignments, ties to science framework(s), references, and related lessons.

496

The Clementine satellite  

SciTech Connect

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.

Not Available

1994-06-01

497

The Dynamic Radio Sky  

NASA Astrophysics Data System (ADS)

The radio band is known to be rich in variable and transient sources, but exploration of it has only begun only in the last few years. Relevant time scales are as small as a fraction of a nanosecond (giant pulses from the Crab pulsar). Short transients (less than one second, say) have signal structure in the time-frequency plane at the very least because of interstellar plasma propagation effects (dispersion and scattering), and in some cases due to emission structure. Optimal detection requires handling a range of signal types in the time-frequency plane. Short bursts by necessity have very large effective radiation brightness temperatures associated with coherent emission processes. This paper surveys relevant source classes and summarizes propagation effects that must be considered to optimize detection in large-scale surveys. Scattering horizons for the interstellar and intergalactic media are defined, and the role of the radio band in panchromatic and multimessenger studies is discussed.

Cordes, James M.

2012-04-01

498

Mobile radio - An overview  

NASA Astrophysics Data System (ADS)

Following a brief prologue and historical overview, such technical issues as the repertoire of systems and services, management of the airwaves, the operating environment, service quality, network issues and cell size, channel coding and modulation, speech coding, diversity, multiplex, and multiple access (FDMA, TDMA, CDMA) are discussed. Also addressed are the potential economic and sociological impacts of mobile radio communications in the wake of the redistribution of airwaves at the World Administrative Radio Conference WARC '92. Performance dependence on multipath delay (related to the cell size and terrain configuration), Doppler frequency (related to the carrier frequency, data rate, and the speed of vehicles), and message length (can dictate the choice of multiple access) is briefly discussed.

Kucar, Andy D.

1991-11-01

499

RTE Radio 1  

NSDL National Science Digital Library

In keeping with the broad landscape of honorable and respected public radio broadcasting, RTE (Radio Telefis Eireann) serves Ireland as its public broadcast network. Over the past few years, the organization has seen fit to develop a strong Web presence, and the Web-browsing public may now avail themselves of the programming via this site. Visitors can peruse a number of thematic sections dedicated to programming that includes shows that investigate religion, contemporary music, and special programs. Some of these specials include tributes to Dean Martin and songs about labor. One particular show that is worth listening to is "The State We Are In", which investigates issues of relevance to Ireland. The current set of programs looks at how Irish cities are planned and includes sessions with different persons in government and private industry.

2005-01-01

500

Apparent precision of GPS radio occultation temperatures  

NASA Astrophysics Data System (ADS)

The abundant atmospheric data provided by radio occultation (RO) via the Global Positioning System satellite network have improved short and long-term forecasts and have demonstrated the potential to provide a long-term, consistent, and independent climate dataset. Previous studies have already verified the consistency and reliability of the RO method, listing a range of precision estimates. Uncertainties arising during temperature retrievals, and confounding effects of atmospheric variability, have made the precision of RO temperature data difficult to determine. In this paper, we introduce the concept of apparent precision, and describe a simple, robust method for estimating the apparent temperature precision using data from the COSMIC project. We examine apparent RO temperature precision by latitude, and find it to be somewhat lower than previous estimates. We attribute this to apparent precision being a function of the true precision plus representativeness errors.

Staten, Paul W.; Reichler, Thomas

2009-12-01