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1

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

2

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.

3

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.

4

Direct Broadcast Satellite: Radio Program  

NASA Technical Reports Server (NTRS)

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.

1992-01-01

5

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

6

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

7

Towards Generic Satellite Payloads: Software Radio  

Microsoft Academic Search

Satellite payloads are becoming much more complex with the evolution towards multimedia applications. Moreover satellite lifetime increases while standard and services evolve faster, necessitating a hardware platform that can evolves for not developing new systems on each change. The same problem occurs in terrestrial systems like mobile networks and a foreseen solution is the software defined radio technology. In this

Catherine Morlet; Marie-laure Boucheret; Vencent Calmettes; Béatrice Paillassa; Tanguy Pérennou

2003-01-01

8

Packet radio in the amateur satellite service  

NASA Astrophysics Data System (ADS)

A review of the satellite-based packet radio activities taking place in the Amateur Radio Service is presented. Five projects are discussed. The Digital Communications Experiment (DCE) on Uosat OSCAR-11 is a store-and-forward system that is accessed by a limited number of stations around the world designated as DCE gateways. These gateway stations retrieve and store messages forwarded to them via terrestrial packet radio networks. The Japanese FO-12 satellite is a store-and-forward system, and its user interface is much like computer bulletin boards accessed via land lines. It is available for use by all radio amateurs with the required equipment. Both UO-11 and FO-12 are in LEO.

Diersing, Robert J.; Ward, Jeffrey W.

1989-02-01

9

Doppler shift of radio signals transmitted between orbiting satellites  

Microsoft Academic Search

The Doppler shift of radio signals transmitted between two satellites in the ionsophere is characterized by a general expression that is applicable at VHF and above, where the contributions to the Doppler shift depend on (1) the rate of change of the free path between the satellites, (2) the satellite mean velocity and electron concentration gradients, (3) the moment of

P. L. Dyson; J. A. Bennett

1982-01-01

10

Propagation Effects at Radio Frequencies on Satellite Navigation Systems.  

National Technical Information Service (NTIS)

The report discusses the effects of the neutral and ionized atmosphere on radio frequency signals used in satellite navigation systems. Knowledge of the signal velocity along the transmission path is necessary to properly interpret the navigation measurem...

V. L. Pisacane M. M. Feen

1974-01-01

11

Wave propagation and earth satellite radio emission studies  

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

12

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

13

Method of resolving radio phase ambiguity in satellite orbit determination  

Microsoft Academic Search

For satellite orbit determination, the most accurate observable available today is microwave radio phase, which can be differenced between observing stations and between satellites to cancel both transmitter- and receiver-related errors. For maximum accuracy, the integer cycle ambiguities of the doubly differenced observations must be resolved. To perform this ambiguity resolution, a bootstrapping strategy is proposed. This strategy requires the

Charles C. Councelman III; Richard I. Abbot

1989-01-01

14

76 FR 591 - Determination of Rates and Terms for Preexisting Subscription and Satellite Digital Audio Radio...  

Federal Register 2010, 2011, 2012, 2013

...Docket No. 2011-1 CRB PSS/Satellite II] Determination of Rates and Terms for Preexisting Subscription and Satellite Digital Audio Radio Services AGENCY...for preexisting subscription and satellite digital audio radio services...

2011-01-05

15

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.

16

Global Navigation Satellite System Software Defined Radio.  

National Technical Information Service (NTIS)

There are two major trends that are driving the nature of GNSS receiver development today. First, there is a growing number of Global Navigation Satellite Systems (GNSS) that exist or are under development, so that in the near future, users will potential...

J. McGinthy

2010-01-01

17

ATMOSPHERIC REMOTE SENSING USING SPACE-BASED RADIO NAVIGATION SATELLITES  

Microsoft Academic Search

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

SAMSUNG LIM; CHRIS RIZOS

18

Planning for Instructional Use of Radio and Computers by Satellite.  

ERIC Educational Resources Information Center

This paper surveys approaches that are deemed practical for instructional use of radios and computers by satellite transmission. For each of the two instructional technologies a brief history is provided, a survey of the evaluation studies of effectiveness is given, and a concluding section on planning for application is provided. Because the…

Suppes, Patrick

19

Digital audio for satellite network radio  

NASA Astrophysics Data System (ADS)

The paper presents the time-division-multiplexed (TDM) digital system supplied by Scientific-Atlanta for ABC, CBS, and NBC. The system has a transmission rate of 8.78 Mbps, and can demodulate, decode and demultiplex the data into the desired audio and data channels, supporting data rates equivalent to twenty 15 kHz audio channels at 384 kbps each. Digital transmission is used for data and channel use flexibility, and efficient usage of the satellite transponder. This TDM digital earth terminal configuration provides very high quality audio reception, built-in expansion capability for future services, and relative immunity to terrestrial interference.

McBride, A. L.

1982-04-01

20

Method of resolving radio phase ambiguity in satellite orbit determination  

NASA Technical Reports Server (NTRS)

For satellite orbit determination, the most accurate observable available today is microwave radio phase, which can be differenced between observing stations and between satellites to cancel both transmitter- and receiver-related errors. For maximum accuracy, the integer cycle ambiguities of the doubly differenced observations must be resolved. To perform this ambiguity resolution, a bootstrapping strategy is proposed. This strategy requires the tracking stations to have a wide ranging progression of spacings. By conventional 'integrated Doppler' processing of the observations from the most widely spaced stations, the orbits are determined well enough to permit resolution of the ambiguities for the most closely spaced stations. The resolution of these ambiguities reduces the uncertainty of the orbit determination enough to enable ambiguity resolution for more widely spaced stations, which further reduces the orbital uncertainty. In a test of this strategy with six tracking stations, both the formal and the true errors of determining Global Positioning System satellite orbits were reduced by a factor of 2.

Councelman, Charles C., III; Abbot, Richard I.

1989-01-01

21

47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.  

Code of Federal Regulations, 2013 CFR

...Licensing provisions for the 2.3 GHz satellite digital audio radio service. 25...CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses...Licensing provisions for the 2.3 GHz satellite digital audio radio service....

2013-10-01

22

47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.  

Code of Federal Regulations, 2010 CFR

...Licensing provisions for the 2.3 GHz satellite digital audio radio service. 25...CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses...Licensing provisions for the 2.3 GHz satellite digital audio radio service....

2009-10-01

23

Satellite observations of transient radio impulses from thunderstorms  

SciTech Connect

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 with ground based lightning location data from the National Lightning Detection Network (NLDN), shows that localized regions within thunderstorms are responsible for the creation of the satellite detected rf signals. These regions are connected with the areas of strong radar returns from the NEXRAD Doppler radar system, indicating that they are from regions of intense convection. The authors will also show data from several storms detected in the extended Caribbean, in which the height profile of the source regions can be determined. Although as a single low earth orbit satellite FORTE cannot provide global coverage of thunderstorm/lightning events, follow-on satellite constellations should be able to provide detailed information on global lightning in near real-time.

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

1999-06-01

24

78 FR 1252 - CalAmp Wireless Networks Corporation (CWNC), Satellite Products Division, Including On-Site...  

Federal Register 2010, 2011, 2012, 2013

...Wireless Networks Corporation (CWNC), Satellite Products Division, Including On-Site...workers of CalAmp Products, Inc., Satellite Products Division, including on-site...production of converter/amplifiers for satellite television. The Department's...

2013-01-08

25

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

26

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

NASA Technical Reports Server (NTRS)

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.

1993-01-01

27

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

NASA Technical Reports Server (NTRS)

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.

1993-01-01

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) 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.

29

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

NASA Technical Reports Server (NTRS)

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.

1993-01-01

30

76 FR 57923 - Establishment of Rules and Policies for the Satellite Digital Audio Radio Service in the 2310...  

Federal Register 2010, 2011, 2012, 2013

...Establishment of Rules and Policies for the Satellite Digital Audio Radio Service in the 2310-2360...collection requirements contained in the Satellite Digital Audio Radio Service (SDARS...effective date of these rule sections. See Satellite Digital Audio Radio Service...

2011-09-19

31

78 FR 44029 - Establishment of Rules and Policies for the Digital Audio Radio Satellite Service in the 2310...  

Federal Register 2010, 2011, 2012, 2013

...Policies for the Digital Audio Radio Satellite Service in the 2310-2360 MHz Frequency...the revised information collections for Satellite Digital Audio Radio Service (SDARS...Policies for the Digital Audio Radio Satellite Service in the 2310-2360 MHz...

2013-07-23

32

Development of radio seeing monitor using LEO satellite beacons  

Microsoft Academic Search

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

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

2002-01-01

33

Internet Switching by Satellite: An Ultra Fast Processor with Radio Burst Switching.  

National Technical Information Service (NTIS)

This paper introduces a new switching approach for satellites involved in routing statistical traffic, such as Internet Protocol (IP) data. Inherited from the optical domain, Radio Burst Switching (RBS) can combine a coarse switching granularity (such as ...

C. Haardt N. Couville

2005-01-01

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

Symposium on Radio Astronomical and Satellite Studies of the Atmosphere (2nd).  

National Technical Information Service (NTIS)

The first Symposium on Radio Astronomical and Satellite Studies of the atmosphere was held in Corfu, Greece in 1962 under the aegis of NATO Advanced Study Institute program. The second Symposium was held in 1965, sponsored by the Radio Astronomy Branch of...

J. Aarons J. A. Klobuchar R. S. Allen D. A. Guidice

1966-01-01

36

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

37

Effects of a satellite power system on ground-based radio and radar astronomy  

Microsoft Academic Search

It is noted that when the satellite power system (SPS) is in operation, the power signal and its harmonics, which fall close to radio astronomy bands, may cause overloading of input stages. Mitigation will require the development of cryogenically cooled filters. Radiation within radio astronomy bands can arise from transmitter-generated noise, thermal noise from the large solar cell arrays, and

A. R. Thompson

1981-01-01

38

Study of mutual occultation phenomena of the Galilean satellites at radio wavelengths  

NASA Astrophysics Data System (ADS)

We present preliminary results for our study of mutual phenomena of the Galilean satellites performed at radio wavelengths with the Medicina and Noto antennas of the Istituto di Radioastronomia - INAF, and with the Effelsberg 100-m radio telescope of the Max-Planck-Institute for Radioastronomy, Bonn. Measurements of the radio flux density variation during the mutual occultations of Io by Europa and Ganymede were carried out during the PHEMU09 campaign at 22 GHz and 43 GHz. Flux density variations observed at radio wavelengths are consistent with the typical optical patterns measured when partial occultations occur.

Pluchino, S.; Salerno, E.; Pupillo, G.; Schillirò, F.; Kraus, A.; Mack, K.-H.

2010-01-01

39

Mobile radio alternative systems study satellite/terrestrial (hybrid) systems concepts  

NASA Technical Reports Server (NTRS)

The use of satellites for mobile radio service in non-urban areas of the United States in the years from 1985 to 2000 was investigated. Several satellite concepts are considered: a system with single-beam coverage of the fifty United States and Puerto Rico, and multi-beam satellites with greater capacity. All of the needed functions and services identified in the market study are provided by the satellite systems, including nationwide radio access to vehicles without knowledge of vehicle location wideband data transmission from remote sites, two way exchange of short data and control messages between vehicles and dispatch or control centers, and automatic vehicle location (surveillance). The costs of providing the services are within acceptable limits, and the desired returns to the system investors are attractive. The criteria by which the Federal Communication judges the competing demands for public radio spectrum are reviewed with comments on how the criteria might apply to the consideration of land mobile satellites. Institutional arrangements for operating a mobile satellite system are based on the present institutional arrangements in which the services are offered to the end users through wireline and radio common carriers, with direct access by large private and government users.

Kiesling, J. D.; Anderson, R. E.

1983-01-01

40

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

NASA Technical Reports Server (NTRS)

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

Dobrozhanskiy, V.; Rybkin, V.

1980-01-01

41

CME-associated Radio Bursts from Satellite Observations  

NASA Astrophysics Data System (ADS)

Coronal mass ejections (CMEs) are closely associated with various types of radio bursts from the Sun. All radio bursts are due to nonthermal electrons, which are accelerated during the eruption of CMEs. Radio bursts at frequencies below about 15 MHz are of particular interest because they are associated with energetic CMEs that contribute to severe space weather. The low-frequency bursts need to be observed primarily from space because of the ionospheric cutoff. The main CME-related radio bursts are associated are: type III bursts due to accelerated electrons propagating along open magnetic field lines, type II bursts due to electrons accelerated in shocks, and type IV bursts due to electrons trapped in post-eruption arcades behind CMEs. This paper presents a summary of results obtained during solar cycle 23 primarily using the white-light coronagraphic observations from the Solar Heliospheric Observatory (SOHO) and the WAVES experiment on board Wind. Particular emphasis will be placed on what we can learn about particle acceleration in the coronal and interplanetary medium by analyzing the CMEs and the associated radio bursts.

Gopalswamy, Nat

2012-05-01

42

CME-Associated Radio Bursts from Satellite Observations  

NASA Technical Reports Server (NTRS)

Coronal mass ejections (CMEs) are closely associated with various types of radio bursts from the Sun. All radio bursts are due to nonthermal electrons, which are accelerated during the eruption of CMEs. Radio bursts at frequencies below about 15 MHz are of particular interest because they are associated with energetic CMEs that contribute to severe space weather. The low-frequency bursts need to be observed primarily from space because of the ionospheric cutoff. The main CME-related radio bursts are associated are: type III bursts due to accelerated electrons propagating along open magnetic field lines, type II bursts due to electrons accelerated in shocks, and type IV bursts due to electrons trapped in post-eruption arcades behind CMEs. This paper presents a summary of results obtained during solar cycle 23 primarily using the white-light coronagraphic observations from the Solar Heliospheric Observatory (SOHO) and the WAVES experiment on board Wind. Particular emphasis will be placed on what we can learn about particle acceleration in the coronal and interplanetary medium by analyzing the CMEs and the associated radio bursts.

Gopalswamy, Nat

2012-01-01

43

Satellite-aided mobile radio concepts study: Concept definition of a satellite-aided mobile and personal radio communication system  

NASA Technical Reports Server (NTRS)

The satellite system requires the use of a large satellite antenna and spacecraft array power of about 12 kW or more depending on the operating frequency. Technology developments needed include large offset reflector multibeam antennas, satellite electrical power sybsystems providing greater than 12 kW of power, signal switching hardware, and linearized efficient solid state amplifiers for the satellite-aided mobile band. Presently there is no frequency assignment for this service, and it is recommended that an allocation be pursued. The satellite system appears to be within reasonable extrapolation of the state of the art. It is further recommended that the satellite-aided system spacecraft definition studies and supporting technology development be initiated.

Anderson, R. E.

1979-01-01

44

Analysis of satellite measurements of terrestrial radio noise  

NASA Technical Reports Server (NTRS)

Worldwide distributions of terrestrial radio noise as monitored by Radio Astronomy Explorer 1 (RAE 1) generated and compared with CCIR predictions. These contour maps show the global morphology of radio noise at 6.55 and 9.18 MHz for fall, winter, spring and summer during the local time blocks of 00-08 LT and 16-24 LT. These computer produced maps show general agreement with CCIR predictions over large land masses. The RAE and CCIR maps diverge at high latitudes over Asia and frequently over ocean regions. Higher noise levels observed by RAE at high latitudes are attributed to magnetospheric emission while higher noise levels observed by RAE over Asia are attributable to high power transmitters. Analysis of RAE noise observations in conjunction with various geophysical phenomena showed no obvious correlation.

Bakalyar, G.; Caruso, J. A.; Vargas-Vila, R.; Ziemba, E.

1974-01-01

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

New Satellite Constellation Uses Radio Occultation to Monitor Space Weather  

Microsoft Academic Search

A constellation of six satellites, expected to enhance space weather research, improve terrestrial meteorology forecasts, and monitor climate change, were launched 15 April from Vandenberg Air Force Base, Calif.

Mohi Kumar

2006-01-01

47

Terrestrial Myriametric Radio Burst Observed by IMAGE and Geotail Satellites  

NASA Technical Reports Server (NTRS)

We report IMAGE and Geotail simultaneous observations of a terrestrial myriametric radio burst (TMRB) detected on August 19, 2001. The TMRB was confined in time (0830-1006 UT) and frequency (12-50 kHz), suggesting a fan beam-like emission pattern from a single discrete source. Analysis and comparisons with existing TMR radiations strongly suggest that the TMRB is a distinct emission perhaps resulting from dayside magnetic reconnection instigated by northward interplanetary field condition.

Fung, Shing F.; Hashimoto, Kozo; Boardsen, Scott A.; Garcia, Leonard N.; Green, James L.; Matsumoto, Hiroshi; Reinisch, Bodo W.

2010-01-01

48

DSN radio science system description and requirements. [for satellite radio astronomy experiments  

NASA Technical Reports Server (NTRS)

The data system created to collect the functions performed by the Deep Space Network in support of spacecraft radio science experiments is described. Some of the major functional requirements presently being considered for the system are delineated.

Mulhall, B. D. L.

1977-01-01

49

Phase-controlled group antennas for satellite mobile radio  

NASA Astrophysics Data System (ADS)

A new concept for a phased array antenna in L-band for mobile satellite communications is presented. The array as a whole is a multilayer structure with integrated four-bit switched stub phase shifters and aperture-coupled right-hand circularly polarized antenna elements. The integrated phased array has an interface for direct computer control.

Ziegler, Volker

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

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

52

Instrumentation for Spacecraft-to-Spacecraft Radio Science Observations of Jupiter and Satellites  

Microsoft Academic Search

Investigations of planetary atmospheres and surfaces via radio occultation and scattering techniques have been successfully conducted on many planets and several large satellites in the solar system using one-way downlink from a spacecraft to a ground station. Limitations on the received SNR or geometrical coverage can be overcome with alternate observation configurations. Uplink observations where a signal is transmitted from

Sami Asmar; W. Folkner; D. Hinson; L. Iess; I. Linscott; E. Marouf; P. Tortora

2010-01-01

53

On the Passage of High-Level Pulsed Radio Frequency Interference Through a Nonlinear Satellite Transponder  

Microsoft Academic Search

Under examination in this paper is the uncoded bit error rate (BER) performance of a satellite communications system in which the modulation scheme is binary PSK, the transponder contains an arbitrary amplitude nonlinearity, and high-level pulsed radio frequency interference (RFI) is present. The RFI may be characterized as either pulsed Gaussian noise or pulsed CW, with the burst duration shorter

AARON WEINBERG

1984-01-01

54

Workshop on Satellite Power Systems (SPS) Effects on Optical and Radio Astronomy  

Microsoft Academic Search

The impacts of the satellite solar power system on astronomy are concluded to be: increased sky brightness, reducing the effective aperture of terrestrial telescopes; microwave leakage radiation causing erroneous radioastronomical signals; direct overload of radioastronomical receivers at centimeter wavelengths; and unintentional radio emissions associated with massive amounts of microwave power or with the presence of large, warm structures in orbit

G. M. Stokes; P. A. Ekstrom

1980-01-01

55

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

NASA Astrophysics Data System (ADS)

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

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

56

Radio sky mapping from satellites at very low frequencies  

NASA Technical Reports Server (NTRS)

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

Storey, L. R. O.

1991-01-01

57

Numerical arc segmentation algorithm for a radio conference - A software tool for communication satellite systems planning  

NASA Technical Reports Server (NTRS)

A detailed description of a Numerical Arc Segmentation Algorithm for a Radio Conference (NASARC) software package for communication satellite systems planning is presented. This software provides a method of generating predetermined arc segments for use in the development of an allotment planning procedure to be carried out at the 1988 World Administrative Radio Conference (WARC - 88) on the use of the GEO and the planning of space services utilizing GEO. The features of the NASARC software package are described, and detailed information is given about the function of each of the four NASARC program modules. The results of a sample world scenario are presented and discussed.

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

1988-01-01

58

Simultaneous radio and satellite optical measurements of high-altitude sprite current and lightning continuing current  

Microsoft Academic Search

We report coordinated measurements of lightning and resulting sprites using ground-level magnetic field sensors (<0.1 Hz to 30 kHz bandwidth) and the ISUAL instrument on the FORMOSAT-2 satellite. These measurements demonstrate two distinct elements of the connection between the radio and optical emissions. First, the quasi-static magnetic field signature is tightly correlated with the low-altitude optical emissions from the lightning

Steven A. Cummer; Harald U. Frey; Stephen B. Mende; Rue-Ron Hsu; Han-Tzong Su; Alfred B. Chen; Hiroshi Fukunishi; Yukihiro Takahashi

2006-01-01

59

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

Microsoft Academic Search

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

C. A. Higgins

2007-01-01

60

Effects of a satellite power system on ground-based radio and radar astronomy  

NASA Astrophysics Data System (ADS)

It is noted that when the satellite power system (SPS) is in operation, the power signal and its harmonics, which fall close to radio astronomy bands, may cause overloading of input stages. Mitigation will require the development of cryogenically cooled filters. Radiation within radio astronomy bands can arise from transmitter-generated noise, thermal noise from the large solar cell arrays, and possibly from intermodulation, component failures, and turn-on transients. It is noted that noise and harmonics can also be generated by the power-collecting rectennas, and that there may be propagation effects resulting from ionospheric heating. It is concluded that for any radio telescope, a zone of sky will be centered on the arc of satellites and observations here with high sensitivity will be precluded. It is estimated that the width of the zone, as determined by thermal radiation, will vary from about 30 deg for single-antenna telescopes to a few degrees for high-resolution arrays and interferometers. It is noted that since there will be some degradation in performance in bands close to the power signal and its second harmonic, adequate shielding by terrain between radio observatories and power receiving sites will be necessary.

Thompson, A. R.

1981-02-01

61

Radio star and satellite signal scintillation by E region irregularities: A case study  

NASA Astrophysics Data System (ADS)

We present the study of daytime scintillation due to E region irregularities at low latitudes from a set of simultaneous observations on June 3, 1993. The effects of these irregularities are clearly seen on (1) the 103 MHz signal of the radio star 3C 196 recorded at Rajkot and at Thaltej (near Ahmedabad, India), (2) the 244-MHz radio beacon of Fleetsat satellite (73 deg E) recorded at Ahmedabad, and (3) the ionosonde being operated at Ahmedabad. These observations provide an estimate of the irregularity patch with a spatial extent of around 400 km east-west and 80 km north-south. As the subionospheric points of the radio source and satellite observations are quite far apart, a study on the dynamics of these irregularities is also possible which indicates a southward movement of the patch. The drift speed of approx. 60 m/sec is calculated from the upper frequency roll off of the scintillation spectrum at 103 MHz. This is found to be consistent with earlier investigations of blanketing Es near magnetic equator.

Vats, Hari Om; Chandra, Harish; Deshpande, M. R.; Vyas, G. D.

1995-03-01

62

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

63

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

NASA Astrophysics Data System (ADS)

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

Stevenson, S.; Provencher, C.

64

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

NASA Technical Reports Server (NTRS)

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

Stevenson, S.; Provencher, C.

1984-01-01

65

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

66

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

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

67

ATS-6 - Radio Beacon Experiment: The first years. [ionospheric and satellite-to-ground electron content  

NASA Technical Reports Server (NTRS)

The Radio Beacon Experiment aboard Applications Technology Satellite-6 (ATS-6) is designed to measure the total electron content and the ionospheric electron content between the satellite and ground. The spaceborne beacon transmits signals on frequencies of 40, 140, and 360 MHz with amplitude modulations of 1 MHz and/or 0.1 MHz for the measurement of modulation phase, Faraday rotation, and amplitude. The modulation phase delays are calibrated in the satellite and in the ground equipment, and the polarization of the emitted signals are predetermined by standard antenna range techniques. The design of the ATS-6 receiver in Boulder, Colorado, is discussed. The antennae are of the short backfire type described by Ehrenspeck (1967), with nominal gains of 13, 19, and 22 dB at 40, 140, and 360 MHz, respectively. Data recording and overall supervision of the receiver is carried out by a 16-bit minicomputer with 8 k of memory. Overall performance of the system is satisfactory. Sample data on the monthly median hourly values of the total electron content, plasmospheric content, and shape factor show distinct seasonal and diurnal variations.

Davies, K.; Fritz, R. B.; Grubb, R. N.; Jones, J. E.

1975-01-01

68

Radio science with Voyager 2 at Uranus - Results on masses and densities of the planet and five principal satellites  

Microsoft Academic Search

The authors have analyzed radio Doppler data and star-satellite imaging data from Voyager 2 at Uranus, along with 8 years of ground-based astrometric data, and have obtained improved masses and densities for the satellites of Uranus as well as a new ratio of the mass of the Sun to the mass of the Uranian system of 22902.94±0.04. The mean density

J. D. Anderson; J. K. Campbell; R. A. Jacobson; D. N. Sweetnam; A. H. Taylor

1987-01-01

69

On the passage of high-level pulsed radio frequency interference through a nonlinear satellite transponder  

NASA Technical Reports Server (NTRS)

Attention is given to the uncoded bit error rate (BER) performance of a satellite communications system whose modulation scheme is binary PSK and whose transponder contains an arbitrary amplitude nonlinearity, all in the presence of high level pulsed radio frequency interference (RFI). A general approach is presented for direct BER evaluations, in contrast to other approaches which may employ SNR suppression factors. The computed results are based on arbitrarily specified RFI scenarios, in the presence of hard limiter, clipper, or blanker amplitude nonlinearities. Performance curves demonstrate the superiority of an appropriately chosen blanker when the RFI environment is most severe. The results obtained also pertain to the sensitivity of performance to the information bit rate, signal power variations, and the ratio of CW to noise content. The CW effects are found to be the most severe.

Weinberg, A.

1984-01-01

70

Radio Signatures of November 1998 Leonid Meteor on Transionospheric VHF Satellite Signal  

NASA Astrophysics Data System (ADS)

This letter presents, to our knowledge for the first time, two cases of scintillations of the 244 MHz satellite beacon signal recorded from the geostationary satellite FLEETSATCOM (FSC) (Long: 73°E) at the Haringhata Field Station (HFS) (Lat: 22.97°N Long: 88.50°E Dip: 32°N) of the University of Calcutta on the night of November 16/17, 1998, which corresponds to the peak period of the Leonid meteor shower in terms of its rate and visual magnitude. Scintillations produced by the sporadic-E layer (E s) generated by meteoric ionization are transient and quasi-periodic in nature. This type of scintillations have much shorter durations (˜30-100 s) than those normally observed at night in the equatorial latitudes (˜5 min to couple of hours). It is characterized by a primary deep fade out in field strength, associated with regular ringing patterns before and after it. Generation of quasi-periodic scintillations is believed to be due to a small-scale (scale size ˜100-1000 m) density enhancement or blob which acts as a radio lens in the path of the transionospheric signal. Assuming one-dimensional density irregularities, the peak phase deviation introduced in the radio wave passing through is estimated. The observed scintillation patterns have been simulated considering a series of isolated ionospheric irregularities of different strengths and scale sizes. Critical frequency of the E s layer (f 0E s) measured by the Ahmedabad ionosonde (Lat: 23.03 0N Long: 72.40 0E Dip: 34°N) for the same night shows two isolated spikes which may be due to a sudden increase in plasma density caused by meteoric ionization. In addition, the meteor visual magnitude and cumulative mean flux have been calculated using the meteor intensity data available on the Internet.

Paul, A.; Ray, S.; DasGupta, A.; Chandra, H.

2001-06-01

71

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

NASA Technical Reports Server (NTRS)

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

Laymon, Charles; Srinivasan, Karthik; Limaye, Ashutosh

2011-01-01

72

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

73

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

74

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

75

Validating Satellite Observations of Thermodynamic Variables by Reference Datasets from GPS Radio Occultation  

NASA Astrophysics Data System (ADS)

In the frame of calibration and validation activities of the European Space Agency (ESA), the WEGC prepares and provides long-term GPS radio occultation (RO) reference data from a variety of RO missions (in total up to about 2500 profiles per day) in Generic Earth Observation Metadata Standard (GEOMS) format. Applications of the data include use in the long-loop monitoring of trends related to other spaceborne instruments but also to climate change and variability. Further uses include validation of diverse atmospheric satellite data products and of geophysical retrieval algorithms or also support to scientific evaluation of atmospheric processes. Specifically, we ensure the provision of correlative RO data suitable for in-depth examination of tropospheric and stratospheric fundamental state profiles, such as of temperature, humidity and pressure as function of altitude, from other (satellite) observations. This is highly worthwhile since the unique combination of global coverage, high accuracy and vertical resolution, long-term stability, and virtual all-weather capability makes, in the free atmosphere, the validation with RO data preferable to other methods. The presentation will introduce this project on multi-mission validation by RO, its setup at the WEGC, and the quality and convenient availability of the RO datasets. It will then focus on the discussion of example results of the multi-year validation of temperature, pressure, and density profiles over the upper troposphere and lower stratosphere (UTLS) from Envisat MIPAS and GOMOS data against collocated RO data from CHAMP, Formosat-3/COSMIC, and MetOp-A/GRAS. These validations provide valuable hints for future improvements in the processing of the Envisat data. In addition, the RO dataset is inter-validated with profiling data from ground-based sites defined in the Multi-TASTE and VALID projects (Lidars, etc.), which are related to Envisat validation, and against a high-quality radiosonde dataset (RAOBCORE) available from the Univ. of Vienna, Austria. We show how these results help to obtain quantitative estimates on the quality of RO data (e.g., systematic error bounds) and on their utility to serve as reference data for the targeted climate monitoring and validation applications.

Schwärz, M.; Kirchengast, G.; Leuprecht, A.; Fritzer, J.; Scherllin-Pirscher, B.; Retscher, C.

2012-04-01

76

Conversion of a 30-m former satellite communications antenna to a radio telescope  

NASA Astrophysics Data System (ADS)

A class of large satellite communication antennas built in the mid-1970's comprise a potential set of large antennas available for use by radio astronomers upon upgrade. With the advent of low noise technology these facilities have been superseded in the communications industry by smaller, more manageable facilities. Although many have sat idle and decaying over the intervening years, these facilities remain a potential resource for research and education. A pair of such dishes has been acquired by Georgia Tech and one of the 30 meter antennas has been completely mechanically and electrically stripped and new mechanical, control, RF, and electrical systems installed. The antenna is now driven by four continuous-speed vector-controlled three-phase AC induction motors with variable frequency vector motor drives. Sixteen bit resolution optical absolute position encoders on each axis provide telescope pointing data. Sixteen bit resolution optical absolute position encoders on each axis provide telescope pointing data. A programmable logic controller provides interlock monitoring and control. The antenna is controllable both manually via a portable remote control unit and via a Pentium PC running control software on a real-time UNIX-based platform. The manual unit allows limited control at two user-selectable speeds while computer control allows full tracking capability with accuracies of better than 0.3 arcminutes. The facility can be remotely controlled via the internet, although currently only a dedicated line is used. The antenna has been refitted with an ultra-broadband feed system capable of operating from 1-7 GHz.

Deboer, David R.; Steffes, Paul G.; Glowacki, John M.

1998-05-01

77

The RadioSat (sm) network  

NASA Technical Reports Server (NTRS)

The RadioSat network under development by radio Satellite Corporation will use mobile satellite (MSAT) technology to provide diverse personal communications, broadcast, and navigation services. The network will support these services simultaneously for integrated mobile radios throughout Canada and the United States. The RadioSat network takes advantage of several technological breakthroughs, all coming to fruition by the time the first MSAT satellite is launched in 1994. The most important of these breakthroughs is the enormous radiated power of each MSAT spacecraft - orders of magnitude greater than the radiated power of previous L-band spacecraft. Another important breakthrough is the development of advanced digital audio compression algorithms, enabling the transmission of broadcast quality music at moderate data rates. Finally, continuing dramatic increases in VLSI capabilities permit the production of complex, multi-function mobile satellite radios in very large quantities at prices little more than those of conventional car radios. In addition to performance breakthroughs and their economic implications to RadioSat, the design of the RadioSat network is reviewed.

Noreen, Gary K.

1991-01-01

78

Results of 17 Independent Geopositional Accuracy Assessments of Earth Satellite Corporation's GeoCover Landsat Thematic Mapper Imagery. Geopositional Accuracy Validation of Orthorectified Landsat TM Imagery: Northeast Asia  

NASA Technical Reports Server (NTRS)

This report provides results of an independent assessment of the geopositional accuracy of the Earth Satellite (EarthSat) Corporation's GeoCover, Orthorectified Landsat Thematic Mapper (TM) imagery over Northeast Asia. This imagery was purchased through NASA's Earth Science Enterprise (ESE) Scientific Data Purchase (SDP) program.

Smith, Charles M.

2003-01-01

79

Study of the Earth's Ionosphere by Reception of Radio Waves from Satellites.  

National Technical Information Service (NTIS)

A study of ionospheric scintillations by the reception of signals from the Russian satellite 1962 Cosmos I was undertaken. The satellite transmitted at a frequency of 20 Mc/s and it was found possible to receive the first two harmonics at 40 Mc/s and 60 M...

S. Basu

1964-01-01

80

Inversion and Error Estimation of GPS Radio Occultation Data  

Microsoft Academic Search

In this paper, we describe the GPS radio occultation (RO) inversion process currently used at the University Corporation for Atmospheric Research (UCAR) COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) Data Analysis and Archive Center (CDAAC). We then evaluate the accuracy of RO refractivity soundings of the CHAMP (CHAllenging Minisatellite Payload) and SAC- C (Satellite de Aplicaciones Cientificas-C) missions

Y.-H. KUO; T.-K. WEE; S. SOKOLOVSKIY; C. ROCKEN; W. SCHREINER; D. HUNT; R. A. ANTHES

2004-01-01

81

Modification of the high-latitude ionosphere by high-power hf radio waves. 2. Results of coordinated satellite and ground-based observations  

NASA Astrophysics Data System (ADS)

We present the results of coordinated satellite and ground-based observations of the high-latitude ionospheric phenomena induced by high-power high-frequency (HF) radio waves. The ion outflow phenomenon accompanied by a strong increase in the electron temperature and thermal expansion of plasma was observed in the evening hours, when the high-latitude ionospheric F region was heated by high-power O-mode HF radio waves. The DMSP F15 satellite recorded an increase in the ion number density O+ at an altitide of about 850 km in that period. Ultralow-frequency (ULF) radiation at the modulation frequency 3 Hz of the high-power HF radio waves, which was generated in the ionosphere irradiated by high-power O-mode HF radio waves and accompanied by a strong increase in the electron temperature and the generation of artificial small-scale ionospheric irregularities, was recorded by the CHAMP satellite during the heating experiment in Tromsø in November 5, 2009. The results of the DEMETER satellite observations of extremely low frequency (ELF) radiation at the modulation frequency 1178 Hz of the high-power radio waves in the heating experiments were analyzed using the event of March 3, 2009 as an example.

Blagoveshchenskaya, N. F.; Borisova, T. D.; Kornienko, V. A.; Rietveld, M. T.; Yeoman, T. K.; Wright, D. M.; Rother, M.; Lühr, H.; Mishin, E. V.; Roth, C.; Frolov, V. L.; Parrot, M.; Rauch, J. L.

2011-07-01

82

Results from the northern New Mexico satellite-beacon radio interferometer.  

National Technical Information Service (NTIS)

An interferometer described in the Boston, 1992, meeting of the Beacon Satellite Symposium has been in full operation for over a year now. It consists of four autonomous stations; three are in a triangle 70 km on a side and one is in the center. The stati...

R. Carlos A. Jacobson R. Massey G. Wu

1994-01-01

83

GIANT LOBES OF CENTAURUS A RADIO GALAXY OBSERVED WITH THE SUZAKU X-RAY SATELLITE  

SciTech Connect

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 {Gamma} {approx} 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 {approx}> 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 {approx} 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 n{sub g} {approx} 10{sup -4} cm{sup -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 {beta} parameter around the volume-averaged equilibrium condition {beta} {approx} 1.

Stawarz, L.; Gandhi, P.; Takahashi, T.; Takei, Y. [Institute of Space and Astronautical Science JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)] [Institute of Space and Astronautical Science JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Tanaka, Y. T.; Fukazawa, Y. [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)] [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Madejski, G. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)] [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); O'Sullivan, S. P. [Sydney Institute for Astronomy, School of Physics A28, University of Sydney, Sydney, NSW 2006 (Australia)] [Sydney Institute for Astronomy, School of Physics A28, University of Sydney, Sydney, NSW 2006 (Australia); Cheung, C. C. [National Academy of Sciences, Washington, DC 20001 (United States)] [National Academy of Sciences, Washington, DC 20001 (United States); Feain, I. J. [CSIRO Astronomy and Space Science, ATNF, P.O. Box 76, Epping, NSW 1710 (Australia)] [CSIRO Astronomy and Space Science, ATNF, P.O. Box 76, Epping, NSW 1710 (Australia); Hardcastle, M. J. [School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom)] [School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Kataoka, J.; Takeuchi, Y. [Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan)] [Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Ostrowski, M. [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Krakow (Poland)] [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Krakow (Poland); Reville, B. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)] [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Siemiginowska, A. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Simionescu, A.; Werner, N., E-mail: stawarz@astro.isas.jaxa.jp [KIPAC, Stanford University, 452 Lomita Mall, Stanford, CA 94305 (United States)

2013-03-20

84

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

85

Ice sheet surface features in southwestern Greenland from satellite radio altimetry  

NASA Technical Reports Server (NTRS)

Fourteen SEASAT and ten GEOS-3 satellite radar altimeter groundtracks across a 1 deg x 2.5 deg study area in southwestern Greenland have yielded 3,328 ice sheet surface elevations. The surface elevations derived from SEASAT were recalculated based on a waveform retracking algorithm. The elevations have been utilized to develop a surface profile, a three dimensional surface representation, and surface contours. Analysis of the elevations reveals the presence of surface terraces, some greater than 100 km in length; each terrace is at a discrete elevation. Renormalized SEASAT AGC values are shown to be correlated with the surface slope. The ice surface undulations caused frequent altimeter losses-of-lock. Future satellite radar altimeters could significantly contribute to ice sheet mapping in the next decade, particularly if they incorporate tracking systems with more frequent updates.

Brooks, R. L.; Norcross, G. A.

1982-01-01

86

Comparison of F-region electron density observations by satellite radio tomography and incoherent scatter methods  

NASA Astrophysics Data System (ADS)

In November 1995 a campaign of satellite radiotomography supported by the EISCAT incoherent scatter radar and several other instruments was arranged in Scandinavia. A chain of four satellite receivers extending from the north of Norway to the south of Finland was installed approximately along a geomagnetic meridian. The receivers carried out difference Doppler measurements using signals from satellites flying along the chain. The EISCAT UHF radar was simultaneously operational with its beam swinging either in geomagnetic or in geographic meridional plane. With this experimental set-up latitudinal scans of F-region electron density are obtained both from the radar observations and by tomographic inversion of the phase observations given by the difference Doppler experiment. This paper shows the first results of the campaign and compares the electron densities given by the two methods. Acknowledgements. This work has been supported by the UK Particle-Physics and Astronomy Research Council. The assistance of the director and staff of the EISCAT Scientific Association, the staff of the Norsk Polarinstitutt and the director and staff of the Swedish Institute of Space Physics is gratefully acknowledged. In addition the authors would like to thank Professor Evgeny Tereshchenko of the Polar Geophysical Institute in Mumansk, Russia and Dr Tuomo Nygrén of the University of Oulu, Finland for provision of data from EISCAT special program time during the November 1995 campaign. Topical Editor D. Alcaydé thanks E. J. Fremouw and another referee for their help in evaluating this paper.--> Correspondence to: I. K. Walker-->

Nygrén, T.; Markkanen, M.; Lehtinen, M.; Tereshchenko, E. D.; Khudukon, B. Z.; Evstafiev, O. V.; Pollari, P.

1996-12-01

87

Interplanetary baseline observations of type 3 solar radio bursts. [by Helios satellites  

NASA Technical Reports Server (NTRS)

Simultaneous observations of type III radio bursts using spacecraft separated by several tenths of an AU were made using the solar orbiters HELIOS-A and -B. The burst beginning at 1922 UT on March 28, 1976, was located from the intersection of the source directions measured at each spacecraft, and from the burst arrival time differences. Wide baseline observations give the radial distance of the source at each observing frequency. Consequently, coronal electron densities and exciter velocity were determined directly, without the need to assume a density model as is done with single spacecraft observations. The separation of HELIOS-A and -B also provided the first measurements of burst directivity at low frequencies. For the March 28 burst, the intensity observed from near the source longitude (HELIOS-B) was significantly greater than from 60 W of the source (HELIOS-A).

Weber, R. R.; Fitzenreiter, R. J.; Novaco, J. C.; Fainberg, J.

1977-01-01

88

Radio wave propagation from antennae at satellite altitudes into the earth-ionosphere waveguide  

NASA Astrophysics Data System (ADS)

The problem of the excitation of the earth-ionosphere waveguide by a short linear antenna or by a small circular one at satellite altitudes is considered. The formulation allows for a spherical regular wave guide as well as for a radially inhomogeneous anisotropic ionsphere. A method for the solution is based on the use of the reciprocity theorems for anisotropic media. Numerical techniques have been developed. Some results for VLF are given. To gain some physical interpretations, the fields of sources at low ionospheric heights were investigated.

Rybachek, S. T.

1995-03-01

89

Future communications satellite applications  

NASA Technical Reports Server (NTRS)

The point of view of the research is made through the use of viewgraphs. It is suggested that future communications satellite applications will be made through switched point to point narrowband communications. Some characteristics of which are as follows: small/low cost terminals; single hop communications; voice compatible; full mesh networking; ISDN compatible; and possible limited use of full motion video. Some target applications are as follows: voice/data networks between plants and offices in a corporation; data base networking for commercial and science users; and cellular radio internodal voice/data networking.

Bagwell, James W.

1992-01-01

90

Design of the Radio Frequency (RF) Subsystem Printed Circuit Boards for the Petite Amateur Navy Satellite (PANSAT).  

National Technical Information Service (NTIS)

The Petite Amateur Navy Satellite (PANSAT) is a small digital communication satellite being developed by the Space Systems Academic Group and the Naval Postgraduate School. This thesis describes the layout of the three final flight printed circuit boards ...

C. A. Lahti

1997-01-01

91

The threat to radio astronomy from radio pollution  

Microsoft Academic Search

The interference of man-made signals to radio astronomy is discussed and changes to the international radio regulations are proposed to protect the future of radio astronomy. The benefits of radio astronomy are outlined and the problem of shared frequency bands is described. The interference caused by the Soviet Glonass satellite is used to illustrate the problems caused by interference.

R. J. Cohen

1989-01-01

92

Capacity of a MultiBeam, Multi-Satellite CDMA Mobile Radio Network with Interference-Mitigating Receivers  

Microsoft Academic Search

More and more interference-mitigating algorithms are being investigated in an attempt to increase the capacity of code-division multiple-access radio networks. At the moment, the main question about interference-resilient receivers is: Do they really bring forth the capacity increase they promise on theoreti- cal grounds? The aim of this study is to give a preliminary answer to such a question, through

Riccardo De Gaudenzi; Filippo Giannetti; Marco Luise

1997-01-01

93

Packet radio tests, Lake Fryxell  

NSF Publications Database

Title : Packet radio tests, Lake Fryxell Type : Antarctic EAM NSF Org: OD / OPP Date : January 09 ... Memorandum (Satellite Packet Radio Tests at Lake Fryxell) To: Files S.7 (Environment) During the ...

94

Improved Satellite-Monitored Radio Tags for Large Whales: Dependable ARGOS Location-Only Tags and a GPS-Linked Tag to Reveal 3-Dimensional Body- Orientation and Surface Movements.  

National Technical Information Service (NTIS)

Two different semi-implantable satellite-monitored radio tag technologies will be developed for whales: (1) a programmable, location-only (LO) Argos tag using contemporary technology will be available in two lengths and be adaptable to testing a variety o...

B. Mate

2012-01-01

95

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

96

Low Earth orbit communications satellite  

NASA Technical Reports Server (NTRS)

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.

1992-01-01

97

75 FR 5513 - Determination of Rates and Terms for Preexisting Subscription Services and Satellite Digital...  

Federal Register 2010, 2011, 2012, 2013

...Preexisting Subscription Services and Satellite Digital Audio Radio Services AGENCY...governing the rates for the preexisting satellite digital audio radio services' use of...period 2007 through 2012 for preexisting satellite digital audio radio services...

2010-02-03

98

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

99

Radio occultation electron density profiles from the FORMOSAT-3/COSMIC satellites over the Brazilian region: A comparison with Digisonde data  

NASA Astrophysics Data System (ADS)

This study aims to validate the electron density profiles from the FORMOSAT-3/COSMIC satellites with data from Digisondes in Brazil during the low solar activity period of the years 2006, 2007 and 2008. Data from three Brazilian Digisondes located in Cachoeira Paulista (22.7°S, 45°W), São Luís (2.5°S, 44.2°W) and Fortaleza (3.8°S, 38°W) were used in the comparisons. Only the profiles whose density peak have been obtained near the stations coordinates were chosen for the comparison. Although there is generally good agreement, some cases of discrepancies are observed. Some of these discrepancies cannot be explained simply by the differences in the position and local time of the measurements made by the satellite and the ground-based station. In such cases it is possible that local conditions, such as the presence of a trans-equatorial wind or electron density gradients, could contribute to the observed differences. Comparison of the F2 layer peak parameters, the NmF2 and hmF2, obtained from the two techniques showed that, in general, the agreement for NmF2 is pretty good and the NmF2 has a better correlation than hmF2. Cachoeira Paulista had the worst correlation for hmF2 possibly because this station is situated in the region under the influence of the equatorial ionization anomaly, a region where it is more difficult to apply the RO technique without violating the spherical symmetry condition.

Ely, C. V.; Batista, I. S.; Abdu, M. A.

2012-06-01

100

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

101

Geodetic Applications of Radio Interferometry  

Microsoft Academic Search

These proceedings contain the papers presented during Symposium No. 5, Geodetic Applications of Radio Interferometry, of the International Association of Geodesy General Meeting held in Tokyo, May 7-8, 1982. The symposium, organized by the IAG Special Study Group 2.51 on Radio Interferometry, had eight sessions and 3 6 papers. Radio interferometry on satellites, such as GPS, was not included because

C. Boucher

1983-01-01

102

[Theme Issue: Communications Satellites.  

ERIC Educational Resources Information Center

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

Howkins, John, Ed.

1976-01-01

103

Feasibility study on radio communications using high altitude radio platform in the stratosphere - Applicability to mobile radio and coverage performance  

Microsoft Academic Search

It is possible that a platform, powered by microwaves beamed from the earth, carrying radio equipment and flying in the stratosphere, could be used for radio relay such as satellite communications, terrestrial microwave radio relay, land mobile base stations. In the Communication Research Laboratory, feasibility studies were started in 1989 on application of the high altitude radio platform (HARP) to

Taiji Saruwatari

1991-01-01

104

Wireless transmission using universal software radio peripheral  

Microsoft Academic Search

Software-Defined Radio (SDR) is a technique using software to make the radio functions hardware independent. SDR is starting to be the basis of advanced wireless communication systems such as Joint Tactical Radio System (JTRS). More interestingly, the adoption of SDR technology by JTRS program is followed by military satellite communications programs. In the development of the SDR implementation, GNU Radio

Z. Tong; M. S. Arifianto; C. F. Liau

2009-01-01

105

77 FR 2241 - Radio Broadcasting Services; Ehrenberg, First Mesa, Kachina Village, Wickenburg, and Williams, AZ...  

Federal Register 2010, 2011, 2012, 2013

...RM-11517, RM-11518; DA 11-2058] Radio Broadcasting Services; Ehrenberg, First...Williams, AZ; and Application of Univision Radio License Corporation, KHOV-FM, Wickenburg...proposal, RM-11517, filed by Rocket Radio, Inc., proposes the allotment of...

2012-01-17

106

Satellite orbit predictor  

NASA Technical Reports Server (NTRS)

An analog aid to determine satellite coverage of Emergency Locator Transmitters Emergency Position Indicating Radio Beacon (ELT/EPIRB) distress incidence is discussed. The satellite orbit predictor is a graphical aid for determining the relationship between the satellite orbit, antenna coverage of the spacecraft and coverage of the Local User Terminal. The predictor allows the user to quickly visualize if a selected position will probably be detected and is composed of a base map and a satellite track overlay for each satellite.A table of equator crossings for each satellite is included.

Friedman, Morton l.; Garrett, James, Major

107

Magnetospherically reflected, specularly reflected, and backscattered whistler mode radio-sounder echoes observed on the IMAGE satellite: 1. Observations and interpretation  

NASA Astrophysics Data System (ADS)

A survey of echoes detected in 2004-2005 during pulse transmissions from the Radio Plasma Imager (RPI) instrument on the IMAGE satellite has revealed several new features of sounder generated whistler mode (WM) echoes and has indicated ways in which the echoes may be used for remote sensing of the Earth's plasma structure at altitudes <5000 km. In this paper we describe the frequency versus travel time (f - t) forms of the WM echoes as they appear on RPI plasmagrams and discuss qualitatively their raypaths and diagnostic potentials. Based on their reflection mechanism, the WM echoes can be classified as: magnetospherically reflected (MR), specularly reflected (SR), or backscattered (BS). The MR echoes are reflected at altitudes where the local lower hybrid frequency (flh) is equal to the transmitted pulse frequency f, a phenomenon familiar from both theory and passive recordings of WM wave activity. The SR echoes (previously reported in a higher frequency range) are reflected at the Earth-ionosphere boundary, either with wave vector at normal incidence or, more commonly (and unexpectedly, due to ray bending in the layered ionosphere), at oblique incidence. The BS echoes are the result of scattering from small scale size plasma density irregularities close to IMAGE. The echoes are described as discrete, multipath, and diffuse, depending upon the amount of travel-time spreading caused by the presence of field aligned density irregularities (FAIs) along echo raypaths. The WM echoes described in this paper have been observed at altitudes less than 5,000 km and at all latitudes and at most MLTs. The diagnostic potential of these phenomena for remotely studying the distribution of plasma density and composition along the geomagnetic field line B0, as well as the presence of FAIs of varying scale sizes, is enhanced by the tendency for SR and MR echoes to be observed simultaneously along with the upward propagating signals from a spatial distribution of communication VLF transmitters. We believe that our findings about WM propagation and echoing in an irregular medium have important implications for the connection between WM waves and the Earth's radiation belts. In a companion paper by Sonwalkar et al. (2011), we employ ray tracing and refractive index diagrams in quantitative support of this paper and also present two diagnostic case studies of plasma density, ion effective mass, and ion composition along B0.

Sonwalkar, V. S.; Carpenter, D. L.; Reddy, A.; Proddaturi, R.; Hazra, S.; Mayank, K.; Reinisch, B. W.

2011-11-01

108

Corporate Social Responsibility and Corporate Citizenship: Towards Corporate Accountability  

Microsoft Academic Search

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

CARMEN VALOR

2005-01-01

109

Lunar Interferometric Radio Array: LIRA  

Microsoft Academic Search

The Lunar Interferometric Radio Array (LIRA) is a performance driven design, with emphasis on utilizing the unique attributes of the far-side of the moon as a platform for radio astronomy. LIRA consists of three independent Lunar Telescope Units (LTUs), autonomously landed on the moon, and a communications relay satellite orbiting at libration point two (L2). Each LTU deploys a large

John Abbott; Shane Pixton; Christopher J. Roberts; Mahmut Reyhanoglu

2000-01-01

110

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

ERIC Educational Resources Information Center

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

Casey-Stahmer, Anna

1979-01-01

111

26 CFR 1.955-5 - Definition of less developed country corporation.  

Code of Federal Regulations, 2013 CFR

... Foreign corporation A is formed on November 1, 1963, to engage in the business of manufacturing and selling radios in Brazil, a less developed country as of November 1, 1963. Corporation A uses the calendar year as a taxable year....

2013-04-01

112

Mobile satellite broadcast system design  

Microsoft Academic Search

An innovative mobile satellite network that will broadcast data and audio signals (voice and music) to mobiles throughout the contiguous United States through MSAT, a North American mobile satellite system now under construction, is described. Mobiles with suitably equipped radios and small L-band omnidirectional mobile satellite antennas simultaneously receive one data channel and any one of many audio channels. Pages,

Gary K. Noreen

1990-01-01

113

Multinational Corporations.  

National Technical Information Service (NTIS)

Contents: The corporation; Relations with home and host governments; Economic impact--(Balance of payments, Foreign economic policy, Foreign economic relations); Political impact (Expropriation, Foreign policy, Foreign relations, International law).

1975-01-01

114

Boundary Layer Remote Sensing with Combined Active and Passive Techniques: GPS Radio Occultation and High-Resolution Stereo Imaging (WindCam) Small Satellite Concept  

NASA Technical Reports Server (NTRS)

Objective: significant progress in understanding low-cloud boundary layer processes. This is the Single largest uncertainty in climate projections. Radio occultation has unique features suited to boundary layer remote sensing (1) Cloud penetrating (2) Very high vertical resolution (approximately 50m-100m) (3) Sensitivity to thermodynamic variables

Mannucci, A.J.; Wu, D.L.; Teixeira, J.; Ao, C.O.; Xie, F.; Diner, D.J.; Wood, R.; Turk, Joe

2012-01-01

115

Progress toward a full scale mobile satellite system for Canada  

NASA Astrophysics Data System (ADS)

The MSAT satellite, planned for launch in early 1994, will provide full scale, satellite based, mobile voice and data communication services to Canada. The MSAT system will provide mobile telephone, mobile radio and mobile data services to customers on the move in any part of North America. The Telesat Mobile Inc. (TMI) satellite will be backed up by a similar satellite to be operated by the American Mobile Satellite Corporation (AMSC) in the United States. An early entry mobile data service was inaugurated in the second quarter of 1990 using channels leased from INMARSAT on Marisat or Marecs-B. The baseline TMI system is described, beginning with the MSAT satellite under contract. The network architecture and the control system that are under development to support the mobile services are discussed. Since it is clearly desirable to have a North American system, such that customers may buy a mobile earth terminal (MET) from a number of qualified suppliers and be able to use it either in Canada or the U.S., TMI and AMSC are cooperating closely in the development of the space and ground segments of the system. The time scale for the procurement of all the elements of the systems is discussed.

Roscoe, Orest S.

116

Telemetry Data Collection from Oscar Satellite  

NASA Technical Reports Server (NTRS)

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

Haddock, Paul C.; Horan, Stephen

1998-01-01

117

Radio loud far-infrared galaxies  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

118

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  

NASA Technical Reports Server (NTRS)

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 stratified ionosphere has been carried out for conditions appropriate to the observations by the ISIS spacecraft of a solar radio storm in September 1983. The procedure allows Poynting flux spectral densities measured on ISIS to be converted to spectral densities well outside the ionosphere where they can be compared directly with simultaneous observations on ISEE 3. The results demonstrate good agreement over their common observing frequency range (1-2 MHz).

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

1990-01-01

119

Satellite networks for education  

NASA Technical Reports Server (NTRS)

Satellite based educational networking is discussed with particular attention given to the potential uses of communications satellites to help meet educational needs in the United states. Four major subject areas were covered; (1) characteristics and structure of networks, (2) definition of pressures within educational establishment that provide motivation for various types of networks, (3) examination of current educational networking status for educational radio and television, instructional television fixed services, inter- and intra-state educational communication networks, computer networks, and cable television for education, and (4) identification of possible satellite based educational telecommunication services and three alternatives for implementing educational satellite systems.

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

1972-01-01

120

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

NASA Technical Reports Server (NTRS)

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

Paulikas, G. A.

1974-01-01

121

Corporal punishment  

Microsoft Academic Search

Presents a 2-part examination of the literature on corporal punishment in which J. M. Johnston's analyses of the laboratory literature are contrasted with field study literature. It is suggested that laboratory investigators have underemphasized the reality of educational and child-rearing customs while field study investigators have underemphasized the scientific aspects of their efforts. Part 1 presents an historical and psychological

Adah Maurer

1974-01-01

122

Improvements in search and rescue distress alerting and locating using satellites  

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

123

Satellite and Ground Station Configuration for an Iranian National Satellite Communication System.  

National Technical Information Service (NTIS)

A communications satellite system for Iran was designed under contract to National Iranian Radio and Television. Summary results describe the alternatives considered and recommendation configurations for satellites and for major city and rural ground stat...

B. B. Lusignan

1976-01-01

124

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

125

Firefighters' Radios  

NASA Technical Reports Server (NTRS)

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

1976-01-01

126

Mobile satellite service communications tests using a NASA satellite  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

127

Geron Corporation  

NSDL National Science Digital Library

Geron Corporation is a biopharmaceutical company specializing in therapeutic and diagnostic products for age-related diseases. Geron owns several telomerase related patents. Calvin B. Harley of Geron is one of the co-authors of the Science article. Their page describes programs and products related to cellular aging and Cancer Therapeutics. There has been a recent finding regarding telomerase, a gene which affects the mechanisms controlling human cell replication. The site above provides general information on telomerase, current telomere research, and the use of telemorase in medical practice. Telomerase increases the life-span of a cell, and is thus central to both aging and cancer.

1998-01-01

128

TDRS orbit determination by radio interferometry  

Microsoft Academic Search

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

Michael S. Pavloff

1994-01-01

129

Planetary radio astronomy experiment for Voyager missions  

Microsoft Academic Search

The planetary radio astronomy experiment will measure radio spectra of planetary emissions in the range 1.2 kHz to 40.5 MHz. These emissions result from wave-particle-plasma interactions in the magnetospheres and ionospheres of the planets. At Jupiter, they are strongly modulated by the Galilean satellite Io.

J. W. Warwick; J. B. Pearce; R. G. Peltzer; A. C. Riddle

1977-01-01

130

Radio sociology  

NASA Astrophysics Data System (ADS)

A work was conducted, using radio telemetry, to locate a migrating, radio-tagged, sharp-shinned hawk. The hawk was monitored through the noise radiation it created. The hawk was found. During this study, it was found that the concentration of population corresponds with areas of increased noise temperature. Through this study, a bigger study was planned. The study would involved the relationship between a place's radiation signature and its other attributes, such as economic type, population, geographic concentration. The method of radio sociology would be used to track the sources of radio noise.

Swenson, George W., Jr.

1996-04-01

131

Leisure, civil disobedience, and the history of low power FM (LPFM) radio  

Microsoft Academic Search

This paper traces the historical development of two trends in radio policy and practice, “megapower” (corporate) and “micropower” (also termed “pirate” or low power FM) broadcasting. In reaction to a flurry of deregulation and corporate consolidation, a micropower movement has recently emerged. My aim is to illustrate some of the political, social, and historical processes that have shaped radio as

Brett D. Lashua

2005-01-01

132

The Bubbler and Radio Scintillation  

NSDL National Science Digital Library

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

133

College Radio.  

ERIC Educational Resources Information Center

As with commercial stations, the underlying premise of the college radio station is to serve the community, whether it be the campus community or the community at large, but in unique ways often geared to underserved niches of the population. Much of college radio's charm lies in its unpredictable nature and constant mutations. The stations give…

Sauls, Samuel J.

134

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.

135

25 CFR 227.6 - Corporations and corporate information.  

Code of Federal Regulations, 2010 CFR

... false Corporations and corporate information. 227.6 ...227.6 Corporations and corporate information. (a...located, evidence showing compliance with the corporation laws...interest for themselves or in trust. Cross Reference:...

2010-04-01

136

25 CFR 213.14 - Corporations and corporate information.  

Code of Federal Regulations, 2010 CFR

... false Corporations and corporate information. 213.14...213.14 Corporations and corporate information. If...located, evidence showing compliance with the corporation laws...interest for themselves or in trust. Cross Reference:...

2010-04-01

137

25 CFR 213.14 - Corporations and corporate information.  

Code of Federal Regulations, 2010 CFR

... false Corporations and corporate information. 213.14...213.14 Corporations and corporate information. If...located, evidence showing compliance with the corporation laws...interest for themselves or in trust. Cross Reference:...

2009-04-01

138

25 CFR 227.6 - Corporations and corporate information.  

Code of Federal Regulations, 2010 CFR

... false Corporations and corporate information. 227.6 ...227.6 Corporations and corporate information. (a...located, evidence showing compliance with the corporation laws...interest for themselves or in trust. Cross Reference:...

2009-04-01

139

Weather, land satellite sale  

NASA Astrophysics Data System (ADS)

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

Richman, Barbara T.

140

GLONASS and Radio Astronomy  

NASA Astrophysics Data System (ADS)

GLONASS navigation satellites transmit one of their navigation signals in a frequency band that overlaps the frequency band 1610.6-1613.8 MHz used for radio astronomical observations of the spectral line of hydroxyl (OH) at 1612.231 MHz. Following growing levels of interference during the 1980s, IUCAF and GLONASS entered into negotiations. A joint experiment was conducted in November 1992 to verify the levels of interference to different types of radio astronomical measurements and to test possible interference mitigation methods that the GLONASS administration could employ without compromising the integrity of the navigation signal. Twelve radio observatories around the world participated. During the 2-day experiment the centre frequencies of navigation signals were removed from the radio astronomy band and some navigation signals were turned off. The results of the experiment are reviewed. These formed the basis for the GLONASS-IUCAF signed in November 1993, which has served as a model for coordination agreements between GLONASS and many administrations. The agreement sets out s step-by-step plan for interference reduction. The current status and future prospects are reviewed.

Cohen, R. J.

2004-06-01

141

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

Code of Federal Regulations, 2013 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...

2013-10-01

142

A Systems Engineering Tool for Small Satellite Design  

Microsoft Academic Search

The growing popularity of small satellites for applications of all kinds has lead to a marked increase in the number of requests from customers of The Aerospace Corporation for studies involving small satellites. The existing design tools used by the Corporation for concept evaluation of large spacecraft have, in many cases, proven inadequate for these small spacecraft studies. As a

Allan I. McInnes; Daniel M. Harps; Jeffrey A. Lang; Charles M. Swenson

143

TDRS orbit determination by radio interferometry  

NASA Technical Reports Server (NTRS)

In support of a NASA study on the application of radio interferometry to satellite orbit determination, MITRE developed a simulation tool for assessing interferometry tracking accuracy. The Orbit Determination Accuracy Estimator (ODAE) models the general batch maximum likelihood orbit determination algorithms of the Goddard Trajectory Determination System (GTDS) with the group and phase delay measurements from radio interferometry. ODAE models the statistical properties of tracking error sources, including inherent observable imprecision, atmospheric delays, clock offsets, station location uncertainty, and measurement biases, and through Monte Carlo simulation, ODAE calculates the statistical properties of errors in the predicted satellites state vector. This paper presents results from ODAE application to orbit determination of the Tracking and Data Relay Satellite (TDRS) by radio interferometry. Conclusions about optimal ground station locations for interferometric tracking of TDRS are presented, along with a discussion of operational advantages of radio interferometry.

Pavloff, Michael S.

1994-01-01

144

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.

145

Near Term Digital Radio-a first look  

Microsoft Academic Search

An ITT Industries led team is developing the Near Term Digital Radio (NTDR) Information Transport System (ITS) for PM Tactical Radio Communication Systems to meet the growing need for higher capacity digital information distribution on a highly mobile battlefield. The team consists of Motorola, Lockheed Sanders, BBN, SICOM and Group Technology Corporation. The NTDR ITS is based on open architecture

L. Williams; L. Emergy

1996-01-01

146

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

147

Application of mesh network radios to UGS  

NASA Astrophysics Data System (ADS)

During the past five years McQ has been actively pursuing integrating and applying wireless mesh network radios as a communications solution for unattended ground sensor (UGS) systems. This effort has been rewarded with limited levels of success and has ultimately resulted in a corporate position regarding the use of mesh network radios for UGS systems. A discussion into the background of the effort, the challenges of implementing commercial off-the-shelf (COTS) mesh radios with UGSs, the tradeoffs involved, and an overview of the future direction is presented.

Calcutt, Wade; Jones, Barry; Roeder, Brent

2008-05-01

148

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

149

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

150

Broadcast satellite service: The international dimension  

NASA Technical Reports Server (NTRS)

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

1991-01-01

151

Canadian Broadcasting Corporation Archives: Science and Technology  

NSDL National Science Digital Library

This collection of radio and television clips from the archives of the Canadian Broadcasting Corporation (CBC) lets users explore the scientific and medical inventions, discoveries, and developments that have shaped Canada's history. The clips are organized by topic, including climate change, medical research, natural disasters, technology, pollution, and many others. There is also a collection of "On this Day" clips celebrating the anniversaries of important scientific and technological events in Canada.

152

Radio Relays Improve Wireless Products  

NASA Technical Reports Server (NTRS)

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

2009-01-01

153

Satellite sound broadcast research aspect in CRL  

NASA Technical Reports Server (NTRS)

Researches on Satellite Sound Broadcasting Services (SSBS) have become active in the past few years. Activities of the Consultative Committee for International Radio (CCIR) and the World Administrative Radio Conference (WARC), especially about digital systems proposed in the CCIR report, are briefly reviewed. The Communications Research Laboratory (CRL) future plan of SSBS research, stressing propagation rather than communications aspects, is described.

Hase, Yoshihiro; Kondo, Kimio; Ohmori, Shingo

1990-01-01

154

The Cooperative Satellite Learning Project.  

ERIC Educational Resources Information Center

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

Caler, Michelle

155

Radio astronomy  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

156

Satellites Harming Other Satellites.  

National Technical Information Service (NTIS)

A strategy is developed for assessing the harm that one satellite can do to another. A total of 29 modes are identified through which this harm can transpire, and the parameters and characteristics of each are explained. An overall, quantitative index of ...

P. C. Hughes

1991-01-01

157

Corporate punishment: A proposal  

Microsoft Academic Search

Corporate Punishment: A Proposal” is an exercise in logic and creative thinking. I shall argue that no good reasons exist for the supposition that corporations have rights independent of the rights and interests of the persons they serve and that the error of treating corporations as though they do have autonomous rights derives from a sloppy argument from analogy. I

Robert J. Rafalko

1989-01-01

158

Organizing Corporate Memories 1  

Microsoft Academic Search

This paper presents some preliminary thoughts on how corporate memories should be organized in such a way that they maximally contribute to the competitiveness of an organization. We argue that a corporate memory should support three types of organizational learning, which are described. Then we formulate functional requirements and present an architecture for corporate memories that would satisfy these requirements.

Rob van der Spek; Eelco Kruizinga; Gertjan van Heijst

1996-01-01

159

Design of the American Mobile Satellite System  

NASA Technical Reports Server (NTRS)

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

Kittiver, Charles

1991-01-01

160

Pre-Flight Testing and Performance of a Ka-Band Software Defined Radio  

NASA Technical Reports Server (NTRS)

National Aeronautics and Space Administration (NASA) has developed a space-qualified, reprogrammable, Ka-band Software Defined Radio (SDR) to be utilized as part of an on-orbit, reconfigurable testbed. The testbed will operate on the truss of the International Space Station beginning in late 2012. Three unique SDRs comprise the testbed, and each radio is compliant to the Space Telecommunications Radio System (STRS) Architecture Standard. The testbed provides NASA, industry, other Government agencies, and academic partners the opportunity to develop communications, navigation, and networking applications in the laboratory and space environment, while at the same time advancing SDR technology, reducing risk, and enabling future mission capability. Designed and built by Harris Corporation, the Ka-band SDR is NASA's first space-qualified Ka-band SDR transceiver. The Harris SDR will also mark the first NASA user of the Ka-band capabilities of the Tracking Data and Relay Satellite System (TDRSS) for on-orbit operations. This paper describes the testbed's Ka-band System, including the SDR, travelling wave tube amplifier (TWTA), and antenna system. The reconfigurable aspects of the system enabled by SDR technology are discussed and the Ka-band system performance is presented as measured during extensive pre-flight testing.

Downey, Joseph A.; Reinhart, Richard C.; Kacpura, Thomas

2012-01-01

161

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

162

New options for satellite power systems \\/SPS  

Microsoft Academic Search

The operation of a satellite power system (SPS) involves the conversion of solar energy into electrical energy with the aid of facilities carried by a geosynchronous satellite, the transmission of the obtained energy to earth in the form of microwave radio frequency energy, and the conversion of the energy received on earth into dc current for distribution into the network.

G. M. Hanley

1977-01-01

163

Voyager-Jupiter radio science data papers  

NASA Technical Reports Server (NTRS)

The reduction and interpretation of the radio science data from the Voyager 1 and 2 encounters of the planet Jupiter and its satellites resulted in the preparation of several papers for publication in the special Voyager-Jupiter issue of the Journal of Geophysical Research. The radio science and tracking systems of the Deep Space Network provide the data which makes this research possible. This article lists submitted papers by title, with their authors and with abstracts of their contents.

Levy, G. S.; Wood, G. E.

1980-01-01

164

Use of communications. [satellite communication  

NASA Technical Reports Server (NTRS)

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

1975-01-01

165

Simulation of the Mars Ionosphere Radio Occultation Experiments  

NASA Astrophysics Data System (ADS)

The Mars ionosphere radio occultation experiment between the Chinese YH-1 spacecraft and the Russian Phobos-Grunt spacecraft orbiting Mars will be the first satellite to satellite radio occultation experiment in history, which will achieve high quality ionospheric electron density profiles. The technique used in this experiment is analyzed and introduced. Simulations of the radio occultation have been completed. Forward calculations of the radio wave observable for the ionospheric radio occultation events have been done with the 3D ray tracing method and a simple Chapman ionosphere background model. The backward inversion with the forward calculated radio occultation observation data gives reliable and consistent ionospheric electron density profiles, which show the reliability of the simulation algorithms. With the simulation method, the effects of errors from the radio signal phase measurement and the orbit determination of the satellite on the inversion are analyzed in cases. Results show that phase errors of 5% circle have a negligible effect on the daytime ionosphere radio occultation, and lead to an absolute error of less than 4×;10^8 m3 for nighttime electron density profiles. Orbit errors of the satellite mainly pose a systematic rising or descending to the ionosphere height. The above results show that Sino-Russian cooperative Mars ionosphere radio occultation experiments is expected to achieve high quality Mars ionosphere profiles. Their technique regime can be used for the lunar ionosphere exploring.

Hu, X.; Wu, X. C.; Gong, X. Y.; Wang, X.; Xu, Q. C.

2009-07-01

166

The Radio JOVE Project - Shoestring Radio Astronomy  

NASA Technical Reports Server (NTRS)

Radio JOVE is an education and outreach project intended to give students and other interested individuals hands-on experience in learning radio astronomy. They can do this through building a radio telescope from a relatively inexpensive kit that includes the parts for a receiver and an antenna as well as software for a computer chart recorder emulator (Radio Skypipe) and other reference materials

Thieman, J.; Flagg, R.; Greenman, W.; Higgins, C.; Reyes, F.; Sky, J.

2010-01-01

167

The Indian National Satellite System - Insat  

NASA Astrophysics Data System (ADS)

Insat is a multiagency multipurpose operational satellite system for domestic long-distance telecommunications, meteorological earth observation and data relay, direct satellite TV broadcasting, and radio and TV program distribution for rebroadcasting through terrestrial transmitters. The first-generation system currently in operation is described as well as plans for a second-generation Insat-II system. The Insat-II system offers greater immunity against single launch/satellite catastrophies.

Rao, U. R.; Pant, N.; Kale, P. P.; Narayanan, K.; Ramachandran, P.

1987-11-01

168

Engineering calculations for communications satellite systems planning  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

169

A study of satellite emergency locator systems  

NASA Technical Reports Server (NTRS)

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

1977-01-01

170

Space Telecommunications Radio System STRS Cognitive Radio  

NASA Technical Reports Server (NTRS)

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

Briones, Janette C.; Handler, Louis M.

2013-01-01

171

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.

172

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

173

Layered sensing with radio (LSWR)  

NASA Astrophysics Data System (ADS)

An alternative approach to a Layered Sensing System-of-Systems methodology, denoted as LSWR (Layered Sensing With Radio), is outlined in this paper. This is a novel Broadcast-TV-Driven layered sensing technique that shows potential for finding embedded objects within, for example, buildings via leveraging and combining existing commercial satellite technologies with COTS (Commercial Off-the-Shelf) wireless network technologies and state-of-the-art wireless sensor mote technologies. Specifically, compact sensor mote technologies are employed in a cost-effective manner to interface with and control low-cost satellite radio/broadcast tuners. With this approach, initial concepts of this type are investigated via the analysis of compact custom sensor node technology (i.e. wireless sensor mote interfaced with satellite broadcast tuner) integrated onto a UGV (unmanned ground vehicle) robot arm for purposes developing prototype UGV robot systems with passive integrated RF sensors that support, for example, networked thru-wall embedded object detection. The primary category of commercial satellite signal considered for analysis within this paper is known as DVB (Digital Video Broadcast).

Mitra, Atindra K.

2010-04-01

174

Solar Physics with Radio Observations  

NASA Astrophysics Data System (ADS)

Radio observations contribute a unique perspective on the many physical phenomena, which occur on the Sun. From thermal bremsstrahlung emission in the quiet solar atmosphere and filaments, to thermal gyroresonance emission in strongly magnetized solar active regions, to the nonthermal emission from MeV electrons accelerated in flares, observations of radio emission provide a powerful probe of physical conditions on the Sun and provide an additional means of understanding the myriad phenomena which occur there. Moreover, radio observing techniques have led the way in developing and exploiting Fourier synthesis imaging techniques. The Nobeyama Radioheliograph, commissioned in June, 1992, soon after the launch of Yohkoh satellite in August, 1991, is the most powerful, solar-dedicated Fourier synthesis in the world, now capable of imaging the full disk of the Sun simultaneously at frequencies of 17 and 34 GHz, with an angular resolution as much as 10" and 5", respectively, and with a time resolution as fine as 100 msec. Between 27-30 October, 1998, the Nobeyama Radio Observatory and the National Astronomical Observatory of Japan hosted the Nobeyama Symposium on Solar Physics with Radio Observations, an international meeting bringing more than sixty participants together at the Seisenryo Hotel in Kiyosato, for a meeting devoted to reviewing recent progress in outstanding problems in solar physics. Emphasis was placed on radio observations and, in particular, radio observations from the very successful Nobeyama Radioheliograph. These results were compared and contrasted with those that have emerged from the Yohkoh mission. In addition, looking forward to the next solar maximum, new instruments, upgrades, and collaborative efforts were discussed. The result is the more than seventy invited and contributed papers that appear in this volume.

Bastian, T. S.; Gopalswamy, N.; Shibasaki, K.

1999-12-01

175

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

176

STEED: Satellite Threat Evaluation Environment for Defensive Counterspace  

Microsoft Academic Search

The design knowledge company (TDKC) is currently developing a defensive counterspace intelligence tool for the air force research laboratory (AFRL) called the satellite threat evaluation environment for defensive counterspace (STEED). STEED provides analysis collaboration and situational awareness features for satellite systems operators. STEED incorporates a wide variety of data sources, including satellite as a sensor (SAS), space weather, proximity, radio

E. Loomis

2007-01-01

177

Radio Seeing Monitor Interferometer  

NASA Astrophysics Data System (ADS)

A two-element interferometer for monitoring atmospheric phase fluctuations (radio seeing) is presented; this uses the unmodulated beacon signal at 11.715 GHz from a geostationary satellite. The system measures phase differences on the signal received by two small antennas separated by 50 m. The system incorporates the best features from previous designs: a heterodyne phase-lock receiver and an IQ demodulator system. Phase fluctuations measured at this frequency may be extrapolated to millimetric and submillimetric wavelengths since the atmosphere is not dispersive at these frequencies. The instrument has been tested at the Observatory San Pedro Martir (Mexico) at 2800 m above sea level. The final destination of the instrument is Cerro la Negra (Mexico), where the Large Millimeter Telescope is under construction, at an altitude of 4600 m.

Hiriart, David; Valdez, Jorge; Zaca, Placido; Medina, José L.

2002-10-01

178

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

179

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

180

Radio and X-ray states in the X-ray binary Scorpius X-1  

SciTech Connect

Radio observations of Sco X-1 were made on March 10-11, 1989 with the VLA, the WSRT, and the Australian Telescope as part of a multiwavelength campaign with the Ginga X-ray satellite, the IUE satellite, and other ground-based instruments. Two source states were detected in the radio and X-ray data, with Sco X-1 being radio-quiet when it was in the X-ray flaring branch and radio-loud when it was in the X-ray normal branch, the same type of radio-X-ray correlation seen in the Z-sources GX 17 + 2 and Cyg X-2. Both radio-quiet and radio-loud states showed radio spectrum changes indicating a multicomponent radio source, where the high-frequency component is variable on time scales of 2-3 hr. 14 refs.

Hjellming, R.M.; Stewart, R.T.; White, G.L.; Strom, R.; Lewin, W.H.G. (National Radio Astronomy Observatory, Socorro, NM (USA) CSIRO, Div. of Radiophysics, Epping (Australia) Radiosterrenwacht, Dwingeloo (Netherlands) MIT, Cambridge, MA (USA))

1990-12-01

181

A direct broadcast satellite system for the United States - System characteristics  

NASA Astrophysics Data System (ADS)

The transmission plan of the Satellite Television Corporation provides for high-quality reception of National Television System Committee color video signals together with their associated audio and control subcarrier. Quality objectives and system parameters are for the most part consistent with those adopted for region 2 in the final acts of the 1977 World Administrative Radio Conference and incorporated into the final acts of the 1979 world conference. Frequency modulation will be used in order to minimize the cost and complexity of home equipment. A table giving the planned transmission parameters is included, showing a composite bit rate of 692 kbit/s, a frequency of 5.5 MHz, and an IF bandwidth of 16 MHz.

Martin, E. R.

1981-11-01

182

A nonlinear optimal estimation inverse method for radio occultation measurements of temperature, humidity, and surface pressure  

Microsoft Academic Search

An optimal estimation inverse method is presented which can be used to retrieve simultaneously vertical profiles of temperature and specific humidity, in addition to surface pressure, from satellite-to-satellite radio occultation observations of the Earth's atmosphere. The method is a nonlinear, maximum a posteriori technique which can accommodate most aspects of the real radio occultation problem and is found to be

Paul I. Palmer; J. J. Barnett; J. R. Eyre; S. B. Healy

2000-01-01

183

Definition phase of Grand Tour missions/radio science investigations study for outer planets missions  

NASA Technical Reports Server (NTRS)

Scientific instrumentation for satellite communication and radio tracking systems in the outer planet exploration mission is discussed. Mission planning considers observations of planetary and satellite-masses, -atmospheres, -magnetic fields, -surfaces, -gravitational fields, solar wind composition, planetary radio emissions, and tests of general relativity in time delay and ray bending experiments.

Tyler, G. L.

1972-01-01

184

Radio tracking system  

Microsoft Academic Search

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

J. C. Breidenthal; T. A. Komarek

1982-01-01

185

Integrated intersystem coordination 1 1 Paper IAF95.MI.02 presented at the 46th International Astronautical Congress, 2–6 October 1995, Oslo, Norway. or How to obtain more effective access to radio frequencies for satellite communications  

Microsoft Academic Search

An overview of various factors pertaining to reliable and efficient access and utilization of the radio frequency spectrum is presented. Technological, regulatory and commercial innovations that could enhance the efficiency of utilization through minimization of the intersystem and interservice interference are proposed. Suitable approaches to increase the efficacy of the intersystem coordination on a global basis are outlined. Considerations of

Wilbur L Pritchard; Jack L Dicks; Ashok K Sinha

1997-01-01

186

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

187

Corporate Conduct Quarterly  

NSDL National Science Digital Library

_Corporate Conduct Quarterly_ is published by the Forum for Policy Research and Public Service at Rutgers, The State University of New Jersey, Camden Campus. The journal aims to offer practical advice on "corporate ethics and compliance." Visitors to the site will find an index of past articles; selected articles are available in full text.

188

Corporal Punishment Revisited.  

ERIC Educational Resources Information Center

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

Wilson, John

2002-01-01

189

Corporation-School Alliances.  

ERIC Educational Resources Information Center

As federal support has declined, corporations have played a more active role in education. But business, schools, policymakers, and students often disagree on the purpose and desired content of education. Cooperative programs have been developed to resolve this communication gap, but many concerned remain skeptical about the corporation-school…

Ascher, Carol

1984-01-01

190

Corporate governance and disappointment  

Microsoft Academic Search

This paper raises fundamental questions about the political and economic conditions and consequences of UK and US corporate governance. It does so by locating corporate governance in present day capitalism. Politically, the rise of governance since the early 1990s is part of a more general discursive attempt to combine neoliberalism with social responsibility, which works in the specific case of

Ismail Erturk; Julie Froud; Sukhdev Johal; Karel Williams

2004-01-01

191

Kids Development Corporation.  

ERIC Educational Resources Information Center

Kids Development Corporation is a simulation of economic life appropriate for gifted students in grades 4-11, in which students form a corporation; purchase land; learn about building construction, banking, and investing; create a logo; and develop a community. This article describes the program's goals and objectives, schedule of activities, and…

Davison, Betty

1993-01-01

192

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

193

Observed X-ray/Radio Correlation in the Vela Pulsar  

NASA Astrophysics Data System (ADS)

We report the results of simultaneous observations of the Vela pulsar in X-rays and radio from the RXTE satellite and the Mount Pleasant Radio Observatory in Tasmania. We sought correlations between the Vela's X-ray emission and radio arrival times on a pulse by pulse basis. At a confidence level of 99.8% we have found significantly higher flux density in Vela's main X-ray peak during radio pulses that arrived early. This excess flux shifts to the `trough' following the 2nd X-ray peak during radio pulses that arrive later. Our results suggest that the mechanism producing the radio pulses is intimately connected to the mechanism producing X-rays. Current models using resonant absorption of radio emission in the outer magnetosphere as a cause of the X-ray emission are explored as a possible explanation for the correlation.

Lommen, A.; Donovan, J.; Gwinn, C.; Arzoumanian, Z.; Harding, A.; Strickman, M.; Dodson, R.; McCulloch, P.; Moffett, D.

2008-02-01

194

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

195

Numerical Arc-Segmentation Algorithm For A Radio Conference  

NASA Technical Reports Server (NTRS)

NASARC computer program developed from general planning principles and decisions of both sessions of World Administrative Radio Conference on Use of Geostationary Satellite Orbit and on Planning of Space Services Utilizing It (WARC-85 and WARC-88). Written to help countries satisfy requirements for nationwide fixed-satellite services from at least one orbital position within predetermined arc. Written in ANSI standard FORTRAN 77.

Whyte, W. A.; Ponchak, Denise S.; Heyward, A. O.; Zuzek, John E.; Spence, R. L.

1992-01-01

196

Satellite telemetry  

NASA Astrophysics Data System (ADS)

Hydrologic application of satellite data collection systems in Brazil is discussed. The Data Collection Platform (DCP) is a telemetry station used for the acquisition of environmental parameters. Artificial satellites are employed to relay the data to receiving centers. Two meteorologic satellite data collection systems are in operation in Brazil: the ARGOS system, on board low-orbit (850 km) satellites of the TIROS-NOAA series, and the Geostationary Operational Satellite (GOES) system, on board geostationary satellites (36,000 km) of the SMS/GOES series. DCPs have been used mainly in the field of hydrology to obtain timely data, to make decisions, and to compose historical records. The first DCP network established in Brazil was in the Tocantins Basin, which has 10 telemetry stations. Other networks are currently being planned. Prototypes of ARGOS and GOES DCPs are being developed that are aimed at further industrialization and improved supply of national demand.

Deolveira, J. R.

1983-08-01

197

Engineers checkout Early Bird-Communication Satellite  

NASA Technical Reports Server (NTRS)

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

1984-01-01

198

Multiple Scientific Uses of Radio Occultation  

NASA Astrophysics Data System (ADS)

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 the effect of atmospheric temperature, pressure, and water vapor on radio signals propagating above the outer edge of Earth's surface, known as the limb. The atmospherically induced delays are tied to atomic clock standards via the Global Positioning System (GPS). Measurements obtained decades apart can be intercompared without concern for intersatellite bias or calibration drift.

Mannucci, Anthony J.; Rocken, Christian

2009-07-01

199

Coordinated observations of PHEMU at radio wavelengths.  

NASA Astrophysics Data System (ADS)

We present preliminary results for our study of mutual phenomena of the Galilean satellites performed at radio wavelengths with the Medicina and Noto antennas of the Istituto di Radioastronomia \\textendash{} INAF, and with the Effelsberg 100-m radio telescope of the Max-Planck-Institute for Radioastronomy. Measurements of the radio flux density variation occurred during the mutual occultations of Io by Europa and Ganymede were carried out during the PHEMU09 campaign at K- and Q-band. Flux density variations observed for the first time at radio wavelengths are consistent with the typical optical patterns measured when partial occultations occurred. The flux density drops indicate a non-linear dependence with the percentage of overlapped area.

Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.; Kraus, A.; Mack, K.-H.

200

Petite Amateur Navy Satellite (PANSAT)  

NASA Technical Reports Server (NTRS)

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

Sakoda, D.; Hiser, J. K.

1989-01-01

201

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

202

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

203

Radio Controlled Clocks  

Microsoft Academic Search

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

Michael A. Lombardi

204

The Frequency Spectrum Radio.  

ERIC Educational Resources Information Center

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

Howkins, John, Ed.

1979-01-01

205

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

206

Rural Communications Planning Methodology for Integrating Satellite and Terrestrial Facilities.  

National Technical Information Service (NTIS)

A computer program is described which optimizes the design of rural telephone networks by choosing the best combination of cable, open wire, VHF radio, communications satellite stations, and placement of local exchanges. Each service area is described for...

R. G. Sharma

1976-01-01

207

An impulse radio communications system  

NASA Astrophysics Data System (ADS)

Pulson Communications has built a prototype impulse radio. The transmitter has an average power of 450 microwatts as measured out of the antenna. This prototype, transmitting high quality audio, was tested to ranges in excess of 7 kilometers. The potential range of this type of system at this power level may exceed 20 kilometers. The prototype had a center frequency of 675 MHz and an approximately equal bandwidth. We used a small wideband omni-directional antenna. While Pulson's laboratory hardware has been optimized for short range, there is no theoretical reason it could not be used for longer range communications, e.g., satellite-to-ground communications or interplanetary probes.

Withington, Paul, II; Fullerton, Larry W.

1993-01-01

208

Monitoring Radio Frequency Interference in Southwest Virginia  

NASA Astrophysics Data System (ADS)

The radio signals received from astronomical objects are extremely weak. Because of this, radio sources are easily shrouded by interference from devices such as satellites and cell phone towers. Radio astronomy is very susceptible to this radio frequency interference (RFI). Possibly even worse than complete veiling, weaker interfering signals can contaminate the data collected by radio telescopes, possibly leading astronomers to mistaken interpretations. To help promote student awareness of the connection between radio astronomy and RFI, an inquiry-based science curriculum was developed to allow high school students to determine RFI levels in their communities. The Quiet Skies Project_the result of a collaboration between the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), and the National Radio Astronomy Observatory (NRAO)_encourages students to collect and analyze RFI data and develop conclusions as a team. Because the project focuses on electromagnetic radiation, it is appropriate for physics, physical science, chemistry, or general science classes. My class-about 50 students from 15 southwest Virginia high schools-participated in the Quiet Skies Project and were pioneers in the use of the beta version of the Quiet Skies Detector (QSD), which is used to detect RFI. Students have been involved with the project since 2005 and have collected and shared data with NRAO. In analyzing the data they have noted some trends in RFI in Southwest Virginia.

Rapp, Steve

2010-01-01

209

Soaring Satellites  

NSDL National Science Digital Library

Working in small teams, learners try to build a satellite that can float for at least five seconds in the marked area of a vertical wind tube. Learners think about and explore the concepts of lift and weight as they try to adapt their satellite to hover between the lines.

Museum Of Science, Boston

2010-01-01

210

Satellite Tracker  

NSDL National Science Digital Library

Students use satellite tracking software available on the Internet to monitor a very large satellite, the International Space Station. Using information from this online resource, students predict and graph the motion of the space station at their location and create a 3-D display of its path through the sky.

Integrated Teaching And Learning Program

211

Fluid satellite  

Microsoft Academic Search

Rotating planet and satellite systems with large mass ratios are examined in terms of the stability of the systems, particularly for conditions which result in the formation of planet-moon systems such as Pluto-Charon. The planet is modeled as a Maclaurin spheroid massive enough to experience little influence by the satellite. Several equilibrium sequences are calculated for the shapes which can

I. Hachisu; Y. Eriguchi

1985-01-01

212

Meteorological satellites  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

213

From Corporate Memory to Corporate Knowledge  

Microsoft Academic Search

Technology enables us to store and recuperate with a Google like interface all documents produced within the boundaries of\\u000a a company. Does this mean we have complete Corporate Memory? Yes and No because there are problems to be solved in Accountability,\\u000a Authority and Responsibility. This is not a free for all environment where people can co-create material of nonuniform quality

Dennis Tsichritzis

2008-01-01

214

Satellite Broadcast of Graphical Weather Data Flight Tested  

NASA Technical Reports Server (NTRS)

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

Mallasch, Paul G.

2000-01-01

215

Rhyme test performance of ACSB (amplitude compandored single sideband), narrow band, and FM radios  

NASA Astrophysics Data System (ADS)

In this fifth of nine reports concerning spectrum efficient technologies, amplitude compandored single sideband (ACSB) radios and narrowband (NB) radios using amplitude and frequency compandors are compared with conventional frequency modulation (FM) radios by using the Dynastat Corporation's diagnostic rhyme test (DRT). This test provides a measure of the intelligibility of a received signal based on listener identification of initial consonant sounds of single syllable words. The test also provides subjective ratings of several aspects of signal quality based on listeners' personal preference.

Wala, P.

1980-03-01

216

The Corporate Library  

NSDL National Science Digital Library

Launched in the summer of 1999 by two long-term partners in Lens Investment Management, this site "is intended to serve as a central repository for research, study and critical thinking about the nature of the modern global corporation, with a special focus on corporate governance and the relationship between company management, their boards and their shareowners." Along with current awareness articles from the staff of The Corporate Library (TCL) and outside sources including Harvard Business School Working Knowledge, CBSMarketWatch, and McKinsey and Co., the site also provides in-depth special reports on CEO Contracts and on Corporate Governance and Performance. The full-text of Power and Accountability, the book written by The Corporate Library's founders Robert AG Monks and Nell Minow, is also available free of charge. In addition, users may search the entire TCL catalog, which includes 25 years' worth of articles emphasizing the best practices in a variety of areas including disclosure and governance and corporate standing.

Minow, Nell.; Monks, Robert A.

217

Radio frequency detection assembly and method for detecting radio frequencies  

DOEpatents

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

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

2010-03-16

218

Satellite relays temperature of Mt. Rainier  

Microsoft Academic Search

An earth-orbiting Nimbus-4 weather satellite is now relaying the temperature of steam emitted from volcanic, snow-capped Mt. Rainier in Washington on command eight times each week as it passes over the 14,41 0-foot mountain.According to USGS and NASA scientists who are teamed up on the project, the satellite, flying at an altitude of about 680 miles, receives radio signals from

Anonymous

1970-01-01

219

Heart Monitoring By Satellite  

NASA Technical Reports Server (NTRS)

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

1978-01-01

220

Radio astronomy  

NASA Technical Reports Server (NTRS)

A K-band reflected-wave ruby maser was used on the 64-meter (DSS-43) antenna at the Tidbinbilla Tracking Station, near Canberra, Australia. Spectral line observations were carried out near 22 GHz for water vapor sources and near 24 GHz for ammonia sources. The water vapor observations were made in the direction of known southern OH and H2O maser sources. All of the previously detected water line sources examined were detected. In addition, two new water vapor maser sources were discovered, G301.1+1.1and G308.9+0.1. The spectrum of G301.0+1.1 is presented six ammonia sources were found: G291.3-0.7, G305.4+0.2, G322.2+0.6, G327.3-0.5, G333.6-0.2, and G268.4-0.8. Spectra of two of these sources, G291.3-0.7 (RCW 57) and G305.4+0.2, are presented. Both show clearly the presence of the quadrupole splitting satellite lines that will allow the determination of NH3 optical depths in these clouds.

Shaffer, R. D.; Mccluskey, J. T.; Gulkis, S.; Klein, M.; Kuiper, T.

1981-01-01

221

Battery voltage variations and radio transmitter temperatures of the small spacecraft  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

222

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

223

Integration of small satellite cost and design models for improved conceptual design-to-cost  

Microsoft Academic Search

In the late 1980's a new satellite paradigm, modern small satellites, arose and opened up a new class of space applications. Since 1991, the Aerospace Corporation has been studying small satellites. Two products of this on-going study are the Small Satellite Cost Model (SSCM) and the Small Satellite Design Model (SSDM). In an effort to better meet design-to-cost goals for

T. Mosher; M. Barrera; D. Bearden; N. Lao

1998-01-01

224

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

225

Corporate Crime Reporter  

NSDL National Science Digital Library

Published since 1986, the Corporate Crime Reporter is a legal newsletter that highlights recent news items about ongoing corporate crime prosecutions, along with featuring interviews with prominent attorneys who work in this rather intriguing field of law practice. The interview section is quite interesting as users can read long-form interviews with major players such as Dan Webb (who was a prosecutor in the Iran-Contra Affair) and Neil Getnick, who prosecuted the Bayer corporation after it was suspected they bilked Medicaid out of approximately $100 million. Visitors can also view various related documents, such as the indictment of Martha Stewart and a Justice Department memo regarding the federal prosecution of business organizations. The site is rounded out by several reports on the top 10 white-collar crime defense lawyers and the top 100 corporate criminals of the 1990s. Overall, the site will be of great interest to legal professionals, or those who are interested in learning more about the complex world of corporate crime in the United States.

226

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

227

A study on the relationship between ionospheric correction and data control for GPS radio occultation in Australia  

Microsoft Academic Search

GPS radio occultation, (RO) is an emerging and robust space-based earth observation system, with the potential for atmospheric profiling and meteorological applications. GPS RO requires GPS receivers onboard Low Earth Orbit (LEO) satellites to measure the radio signals from GPS satellites so that the atmospheric profiles of parameters such as temperature, pressure and water vapour can be obtained via a

Kefei Zhang; John Le Marshall; Robert Norman; Chuan-Sheng Wang; Erjiang Fu; Ying Li; Yuriy Kuleshov

2010-01-01

228

Expanding radio astronomy in Africa  

NASA Astrophysics Data System (ADS)

The Square Kilometre Array (SKA) Organisation announced in May 2012 that its members had agreed on a dual site solution for the SKA [1]. South Africa's bid for hosting the SKA has caused a ramp up of radio astronomy in Africa. To develop technology towards the SKA, the South African SKA Project (SKA SA) built a protoype radio telescope in 2007, followed in 2010 the seven antenna Karoo Array Telescope (KAT-7). Next is the 64 antenna MeerKAT, which will merge into SKA Phase 1 in Africa. As SKA Phase 2 is intended to add a high resolution capability with baselines out to 3000 km, the SKA SA brought in partner countries in Africa to host outstations. South Africa has been working with the partners to build capacity to operate the SKA and to benefit from it. The SA Department of Science and Technology (DST) developed a proposal to establish radio telescopes in the partner countries to provide hands-on learning and a capability for Very Long Baseline Interferometry (VLBI) research. Redundant 30 m class satellite antennas are being incorporated in this project.

Gaylard, M. J.

2013-04-01

229

Nanosail-D: The Small Satellite That Could!  

NASA Technical Reports Server (NTRS)

Three years from its initial design review, NanoSail-D successfully deployed its sail on January 20th, 2011. It became the first solar sail vehicle to orbit the earth and the second sail ever unfurled in space. The NanoSail-D mission had two main objectives: eject a nanosatellite from a microsatellite; deploy its sail from a highly compacted volume and low mass system to validate large structure deployment and potential de-orbit technologies. These objectives were successfully achieved and the de-orbit analysis is in process. This paper presents an overview of the NanoSail-D project and insights into how potential setbacks were overcome. Many lessons have been learned during these past three years and are discussed in light of the phenomenal success and interest that this small satellite has generated. NanoSail-D was jointly designed and built by NASA's Marshall Space Flight Center and NASA's Ames Research Center. ManTech/NeXolve Corporation also provided key sail design support. The NanoSail-D experiment is managed by Marshall and jointly sponsored by the Army Space and Missile Defense Command, the Von Braun Center for Science and Innovation and Dynetics Inc. Ground operations support was provided by Santa Clara University, with radio beacon packets received from amateur operators around the world.

Alhorn, Dean C.; Casas, Joseph P.; Agasid, Elwood F.; Adams, Charles L.; Laue, Greg; Kitts, Christopher; O'Brien, Sue

2011-01-01

230

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

231

Plasmaspheric electron content variation in the magnetic equatorial region during space weather events: Results from the CRABEX (Coherent Radio Beacon Experiment) using the beacon onboard the Indian geostationary satellite (GSAT - 2)  

NASA Astrophysics Data System (ADS)

CRABEX is a national scientific program for the investigation of the unique features associated with the equatorial and low latitude ionosphere in the Indian zone using the technique of ionospheric tomography It consists of a beacon transmitter onboard the Indian geostationary satellite GSAT-2 which transmits four coherently generated frequencies - 150 012MHz 400 032MHz along with 1 MHz modulation of these frequencies i e 149 01192 MHz and 399 03192 MHz and a unique ground receiver system designed and set up at Trivandrum dip 0 3 r N to receive these beacon transmissions The data obtained from the measurement of the differential phase between 400 MHz and 150 MHz gives the relative Total Electron Content TEC along the line of sight between the satellite and the ground receiver and the measurement of modulation phase delay of 1 MHz on the above frequencies provides a coarse estimate of TEC These two measurements together give an accurate estimate of TEC along the line of sight from the satellite to the ground receiver and the Faraday rotation measurements give a reliable estimate of electron content upto sim 2000 km i e the ionospheric content IEC The simultaneous measurements of IEC and TEC upto the geo-stationary altitude of 36000 km is used to determine the plasmaspheric electron content PEC The CRABEX program with its another segment consisting of a network of 6 receiver stations over the Indian subcontinent established along 77-78 r E meridian also makes use of the data obtained by receiving the 150 and 400 MHz

Ravindran, Sudha; Manju, G.; Devasia, C. V.; Sridharan, R.; Thampi, S. V.; Sreelatha, P.; Sreeja, V.; Pant, T. K.; Raghava Reddi, C.

232

Resonance and Radio  

ERIC Educational Resources Information Center

The science and technology of radio receives little attention in contemporary education. This article discusses ways to explore the basic operating principles of radio. (Contains 4 figures, 3 footnotes, and 2 notes.)

Starrett, Malin J.

2008-01-01

233

Recommended Radio Terms.  

National Technical Information Service (NTIS)

The report contains the draft of a compilation of 188 radio terms recommended by the USSR Scientific Commission created by the Interdepartmental Commission on Radio Frequencies for use in scientific and technical literature, education, standards, and in t...

A. L. Badalov N. I. Chistyakov V. F. Pchelkin

1972-01-01

234

Mapping with QUASAT (QUAsar SATellite) Using Short Observation Times.  

National Technical Information Service (NTIS)

QUASAT (Quasar Satellite) is the name of a proposed satellite which will be an orbiting Very Long Baseline Interferometry (VLBI) observatory. As currently conceived, QUASAT would be a joint NASA-ESA mission to fly a 15 m diameter radio antenna, with multi...

R. S. Simon J. H. Spencer K. J. Johnston

1985-01-01

235

Aeronautical mobile satellite service: Air traffic control applications  

NASA Technical Reports Server (NTRS)

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

Sim, Dave

1990-01-01

236

Solar power satellites - Microwaves deliver the power  

Microsoft Academic Search

While microwave power transmission from the Solar Power Satellite (SPS) network provides such advantages as availability of the sun's energy for more than 99% of the year, supply five GW of power from each SPS and dc-to-dc transmission efficiency of more than 60%, there are three possible environmental problems associated with the SPS system: radio frequency interference (RFI), local heating

W. C. Brown

1979-01-01

237

Satellite Doppler data processing using a microcomputer  

NASA Technical Reports Server (NTRS)

A microcomputer which was developed to compute ground radio beacon position locations using satellite measurements of Doppler frequency shift is described. Both the computational algorithms and the microcomputer hardware incorporating these algorithms were discussed. Results are presented where the microcomputer in conjunction with the NIMBUS-6 random access measurement system provides real time calculation of beacon latitude and longitude.

Schmid, P. E.; Lynn, J. J.

1977-01-01

238

25 CFR 213.14 - Corporations and corporate information.  

Code of Federal Regulations, 2011 CFR

...RESTRICTED LANDS OF MEMBERS OF FIVE CIVILIZED TRIBES, OKLAHOMA, FOR MINING How to Acquire Leases § 213.14 Corporations and corporate...associations such individual stockholders are interested in mining leases on restricted lands within the State, and whether...

2011-04-01

239

Kids Interactive Telecommunications Project by Satellite (KITES): A Telecommunications Partnership To Empower Middle School Students.  

ERIC Educational Resources Information Center

Kids Interactive Telecommunications Project by Satellite (KITES) is a cooperative international telecommunications partnership involving the University of Lowell, Digital's corporate video network, Videostar Connections Inc. (a satellite networking broker), PanAmSat (a satellite operator), and several other public education institutions in…

LeBaron, John

240

Satellite multiple access systems for mobile communication  

NASA Technical Reports Server (NTRS)

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

Lewis, J. L.

1979-01-01

241

Alaska's giant satellite network  

NASA Astrophysics Data System (ADS)

The evolution and features of the Alaskan telecommunications network are described, with emphasis on the satellite links. The Alaskan terrain is rugged and largely unpopulated. Satcom V provides C-band (6/4 GHz) transmission with 24 transponders, each having a 40 MHz bandwidth. The Alascom company operated 105 4.5 m earth-based antennas for remote villages, which receive both telephone and television services. There are also 27 10-m dishes for regional and military applications and a 30 m dish, one of three dishes for links to the centerminous U.S. Currently, half the villages have private and business telephone communications facilities and 200 villages have access to two television stations, one educational, one entertainment. Teleconferencing is possible for government and educational purposes, and discussions are underway with NASA to establish a mobile radio communications capacity.

Hills, A.

1983-07-01

242

Small satellites  

NASA Technical Reports Server (NTRS)

Satellites smaller than Mimas (r = 195 km) are distinguished by irregular overall shapes and by rough limb topography. Material properties and impact cratering dominate the shaping of these objects. Long fragmentation histories can produce a variety of internal structures, but so far there is no direct evidence that any small satellite is an equilibrium ellipsoid made up of noncohesive gravitationally bound rubble. One many bodies that orbit close to their primary the tidal and rotational components of surface gravity strongly affect the directions of local g and thereby affect the redistribution of regolith by mass wasting. Downslope movement of regolith is extensive on Deimos, and is probably effective on many other small satellites. It is shown that in some cases observed patterns of downslope mass wasting cold produce useful constraints on the satellite's mean density. The diversity of features seen in the few high-resolution images of small satellites currently available suggests that these objects have undergone complex histories of cratering, fragmentation, and regolith evolution.

Thomas, P.; Veverka, J.; Dermott, S.

1986-01-01

243

Extragalactic Radio Sources  

ERIC Educational Resources Information Center

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

Kellerman, Kenneth I.

1973-01-01

244

The software radio architecture  

Microsoft Academic Search

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

J. Mitola

1995-01-01

245

Projection method of sensing and interference areas of an earth observation satellite  

NASA Astrophysics Data System (ADS)

A simple graphic display method for projecting remotely sensed areas of the earth and radio interference areas on a map using a microcomputer and an x-y plotter is presented. Transformation matrices are defined for Mercator, polar stereo, and Lambert projections of satellite imagery. Applications are illustrated in terms of an off-nadir viewing area, mapping a satellite visible area, and mapping a radio interference area between a satellite and terrestrial microwave telecommunications facilities.

Sato, H.; Igarashi, T.; Tsuchiya, K.

246

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

247

Activities of Canadian Satellite Communications, Inc.  

NASA Astrophysics Data System (ADS)

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

1992-12-01

248

Earthwatch Radio: Vanishing Act in the Arctic  

NSDL National Science Digital Library

This radio broadcast features an expert in the study of the Arctic climate who has analyzed more than 20 years of satellite images that show the steady shrinking of the reflective ice cover of the Arctic Ocean. He points out that the disappearing ice cover is highly reflective and is being replaced by dark-colored ocean that absorbs more heat, and that the melting is accelerating. He also warns that the changes may be irreversible. The clip is 2 minutes in length.

Hoops, Richard

2012-02-28

249

Radio frequency interference at the geostationary orbit  

NASA Technical Reports Server (NTRS)

Growing demands on the frequency spectrum have increased the possibility of radio frequency interference (RFI). Various approaches to obtain in orbit RFI data are compared; this comparision indicates that the most practical way to obtain RFI data for a desired orbit (such as a geostationary orbit) is through the extrapolation of in orbit RFI measurements by a low orbit satellite. It is concluded that a coherent RFI program that uses both experimental data and analytical predictions provides accurate RFI data at minimal cost.

Sue, M. K.

1981-01-01

250

Corporate information management guidance  

SciTech Connect

At the request of the Department of Energy`s (DOE) Information Management (IM) Council, IM representatives from nearly all Headquarters (HQ) organizations have been meeting over the past year as the Corporate Guidance Group (CGG) to develop useful and sound corporate information management (IM) guidance. The ability of the Department`s IM community to develop such unified guidance continues to be critical to the success of future Departmental IM planning processes and the establishment of a well-coordinated IM environment between Headquarters and field organizations. This report, with 26 specific corporate IM guidance items documented and unanimously agreed to, as well as 12 items recommended for further development and 3 items deferred for future consideration, represents a highly successful effort by the IM community. The effort has proven that the diverse DOE organizations can put aside individual preferences and work together towards a common and mutually beneficial goal. In examining most areas and issues associated with information management in the Department, they have developed specific, far-reaching, and useful guidance. The IM representatives recommend that the documented guidance items provided in this report and approved by the DOE IM Council be followed by all IM organizations. The representatives also strongly recommend that the guidance process developed by the CGG be the single process for developing corporate IM guidance.

NONE

1997-08-01

251

Corporate Training in Museums  

ERIC Educational Resources Information Center

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

Causey, Adera

2011-01-01

252

Competition and Corporate Performance  

Microsoft Academic Search

Are people right to think that competition improves corporate performance? The author's investigations indicate first that there are some theoretical reasons for believing this hypothesis to be correct but they are not overwhelming. Furthermore, the existing empirical evidence on this question is weak. However, the results reported here, based on the analysis of around 670 U.K. companies, provide some support

Stephen J. Nickell

1996-01-01

253

Second Corporate Plan.  

ERIC Educational Resources Information Center

The Technical and Further Education (TAFE) National Centre for Research and Development has two broad areas of activity: the undertaking and encouragement of research and development projects that are of national significance to TAFE and the dissemination of information on research and development in TAFE. The center issued its first corporate

TAFE National Centre for Research and Development, Payneham (Australia).

254

Corporate strategies: organizational structure.  

PubMed

In previous installments of this series, the authors outlined factors that influence corporation information system strategies. The factor that appears to be most significant is centralization vs. decentralization. This article presents examples of organizational structures, roles and responsibilities for either approach. PMID:10287579

Howe, R C; Oestreicher, V

1988-06-01

255

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

256

Maintaining the corporate memory  

Microsoft Academic Search

A well known fact is that corporations don’t have memories. This is because the majority of the knowledge is maintained in the employees’ heads and when they leave that knowledge walks out with them. This continues to be the bane of process safety as errors get perpetuated and incidents repeated. A system can be created, though, to form and keep a

Jack Chosnek

2010-01-01

257

Characteristics of Corporate Libraries.  

ERIC Educational Resources Information Center

This paper reports on a study conducted to collect the data pertaining to corporate libraries in the United States in order to provide a statistical profile of these special libraries. A review of the literature was performed. The researcher used the online "1996 Directory of Special Libraries and Information Centers," which lists 21,380 special…

Charny, Wendy

258

Ethics and Corporate Governance  

Microsoft Academic Search

The authors draw on wide professional experience to address the recent failures in corporate conduct in the United States, the emerging corrective measures and the increasing public outcry for ethical accountability in organisations and governments. They conclude that it is essential that ethics are integral to the culture of an organization; a superficial grafting on of an ethical code will

Stephen D. Potts; Ingrid Lohr Matuszewski

2004-01-01

259

Satellite Winds  

NSDL National Science Digital Library

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

260

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

261

A Deep Space Network Portable Radio Science Receiver  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

262

Comparative and International Corporate Governance  

Microsoft Academic Search

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

Ruth V. Aguilera; Gregory Jackson

2010-01-01

263

Radio frequency interference mitigation in radio astronomy  

NASA Astrophysics Data System (ADS)

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

Boonstra, Albert-Jan

2005-12-01

264

Taxation of Small Business Corporations  

PubMed Central

On December 6 1979, new legislation substantially changed the taxation of business income from Canadian-controlled private corporations. The new rules will be of particular interest to corporations providing personal, financial or management services, and to professionals contemplating the use of such corporations.

Flynn, W. Rand

1980-01-01

265

Government Deficits and Corporate Liquidity  

Microsoft Academic Search

This study examines the relationship between government deficit and corporate liquidity (cash holdings). Using data of nonfinancial firms in Taiwan from 1981 to 2009, this study finds that corporate liquidity is lower when government deficit is higher. In addition, corporate liquidity is related with other macroeconomic conditions, such as inflation, short-term interest rate, and economic growth. More precisely, results indicate

Naiwei Chen; Siting Yo

2012-01-01

266

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

267

Constructive Engagement with the Corporation  

ERIC Educational Resources Information Center

Many of the gravest concerns that critics of corporate culture have about the consequences of academic-corporate relationships are built on little more than ill-informed speculation, fueled by a lack of direct engagement with corporations. The solution to knowledge gap--and the key to liberation from fears of "creeping corporatization"--may…

Siegel, David J.

2007-01-01

268

Satellite sound broadcasting system, portable reception  

NASA Technical Reports Server (NTRS)

Studies are underway at JPL in the emerging area of Satellite Sound Broadcast Service (SSBS) for direct reception by low cost portable, semi portable, mobile and fixed radio receivers. This paper addresses the portable reception of digital broadcasting of monophonic audio with source material band limited to 5 KHz (source audio comparable to commercial AM broadcasting). The proposed system provides transmission robustness, uniformity of performance over the coverage area and excellent frequency reuse. Propagation problems associated with indoor portable reception are considered in detail and innovative antenna concepts are suggested to mitigate these problems. It is shown that, with the marriage of proper technologies a single medium power satellite can provide substantial direct satellite audio broadcast capability to CONUS in UHF or L Bands, for high quality portable indoor reception by low cost radio receivers.

Golshan, Nasser; Vaisnys, Arvydas

1990-01-01

269

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

270

Radio Science Concepts and Approaches for Jupiter Icy Moons Orbiter  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

271

Near-Infrared Spectra of Uranian Satellites  

NASA Astrophysics Data System (ADS)

We present 0.8 to 2.5 micron spectra taken on June 21 & 22, 1998 UT of the Uranian satellites Miranda, Titania, Ariel, Oberon, and Umbriel. The spectra were taken using The Aerospace Corporation's Near-Infrared Imaging Spectragraph (NIRIS) on the University of California's Lick Observatory 3 meter Shane telescope. These spectra will be compared with previous work including Brown, R.H. and Cruikshank, D.P. (1983) as well as more recent spectra and analysis by Grundy, W. et al. (1999). Support for this research was provided by The Aerospace Corporation's Independent Research and Development Program.

Venturini, C. C.; Lynch, D. K.; Rudy, R. J.; Mazuk, S.; Puetter, R. C.

2001-05-01

272

Radio Frequency Interference Mitigation in Radio Astronomy.  

National Technical Information Service (NTIS)

The next generation of radio telescopes is expected to be one to two orders of magnitude more sensitive than the current generation. Examples of such new telescopes are the Low Frequency Array (LOFAR), currently under construction in the Netherlands, and ...

A. J. Boonstra

2005-01-01

273

Communication policy, corporate language policy and corporate information portal : A Holy Trinity in corporate communications?  

Microsoft Academic Search

Purpose – The aim of this paper is to discuss a theoretical framework for increased integration of a company's communication policy, corporate language policy and corporate information portal with a view to facilitating communication management. Design\\/methodology\\/approach – The paper draws on selected theoretical contributions on corporate language policy with special emphasis on theoretical considerations on the type of language policies

Henrik Simonsen

2009-01-01

274

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".

275

Cognitive Radio will revolutionize American transportation  

SciTech Connect

Cognitive Radio will revolutionize American transportation. Through smart technology, it will anticipate user needs; detect available bandwidths and frequencies then seamlessly connect vehicles, infrastructures, and consumer devices; and it will support the Department of Transportation IntelliDrive Program, helping researchers, auto manufacturers, and Federal and State officials advance the connectivity of US transportation systems for improved safety, mobility, and environmental conditions. Using cognitive radio, a commercial vehicle will know its driver, onboard freight and destination route. Drivers will save time and resources communicating with automatic toll booths and know ahead of time whether to stop at a weigh station or keep rolling. At accident scenes, cognitive radio sensors on freight and transportation modes can alert emergency personnel and measure on-site, real-time conditions such as a chemical leak. The sensors will connect freight to industry, relaying shipment conditions and new delivery schedules. For industry or military purposes, cognitive radio will enable real-time freight tracking around the globe and its sensory technology can help prevent cargo theft or tampering by alerting shipper and receiver if freight is tampered with while en route. For the average consumer, a vehicle will tailor the transportation experience to the passenger such as delivering age-appropriate movies via satellite. Cognitive radio will enhance transportation safety by continually sensing what is important to the user adapting to its environment and incoming information, and proposing solutions that improve mobility and quality of life.

None

2013-07-22

276

Cognitive Radio will revolutionize American transportation  

ScienceCinema

Cognitive Radio will revolutionize American transportation. Through smart technology, it will anticipate user needs; detect available bandwidths and frequencies then seamlessly connect vehicles, infrastructures, and consumer devices; and it will support the Department of Transportation IntelliDrive Program, helping researchers, auto manufacturers, and Federal and State officials advance the connectivity of US transportation systems for improved safety, mobility, and environmental conditions. Using cognitive radio, a commercial vehicle will know its driver, onboard freight and destination route. Drivers will save time and resources communicating with automatic toll booths and know ahead of time whether to stop at a weigh station or keep rolling. At accident scenes, cognitive radio sensors on freight and transportation modes can alert emergency personnel and measure on-site, real-time conditions such as a chemical leak. The sensors will connect freight to industry, relaying shipment conditions and new delivery schedules. For industry or military purposes, cognitive radio will enable real-time freight tracking around the globe and its sensory technology can help prevent cargo theft or tampering by alerting shipper and receiver if freight is tampered with while en route. For the average consumer, a vehicle will tailor the transportation experience to the passenger such as delivering age-appropriate movies via satellite. Cognitive radio will enhance transportation safety by continually sensing what is important to the user adapting to its environment and incoming information, and proposing solutions that improve mobility and quality of life.

None

2013-12-06

277

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

278

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

279

PARTNeR for Teaching and Learning Radio Astronomy Basics  

Microsoft Academic Search

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 TÃl’cnica Aeroespacial) and NASA, it has been turned into an educational radio telescope. PARTNeR (Proyecto

Juan A´ngel Vaquerizo

2010-01-01

280

PARTNeR for Teaching and Learning Radio Astronomy Basics  

Microsoft Academic Search

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

Juan Ángel Vaquerizo

2010-01-01

281

MIMOSA satellite  

NASA Astrophysics Data System (ADS)

MIMOSA microsatellite is sixth satellite of the Czech Republic and it is dedicated to yield new experimental data on total atmosphere density of the upper ionosphere. The complex verification of total density analytical model (TD88) is the main project objective. The only payload on board is a highly sensitive accelerometer MACEK. Moreover, designed accelerometer accuracy (10 -9 ms -2) enables to study a weak forces like reflected solar radiation pressure or pressure of the thermal radiation dissipated by the Earth. Presented paper describes payload properties, satellite and subsystem features, budgets and mission performance. The project is at C/D phase presently. The launch is scheduled for the second half of 2000 and expected lifetime is at least two years.

Peresty, R.; Sehnal, L.; Chvojka, M.; Dostal, P.

2000-03-01

282

Managing Satellites  

NASA Technical Reports Server (NTRS)

Integral Systems, Inc.'s EPOCH 2000 forms the core of NASA's Near Earth Asteroid Rendezvous (NEAR) mission's command and control center. EPOCH 2000, which allows ground operators to monitor and control satellites over a wide area network, owes part of its heritage from work completed to support Goddard Space Flight Center. The software automates telemetry processing, commanding, anomaly detection, and archiving collected data. The NEAR spacecraft, launched in February 1996, will rendezvous in early 1999 and orbit the Asteroid Eros for a year. Integral Systems also provided Low Earth Orbit Autonomous Ground Terminals (LEO-Ts) to NASA. The LEO-T is designed to make it easier and less expensive for principal investigators to obtain telemetry, tracking and control services for their science missions. The company products have supported well over 70 satellite missions aimed at scientific research, meteorology, or communications applications.

1997-01-01

283

The Impact of Radio Interference on Future Radio Telescopes  

NASA Astrophysics Data System (ADS)

While future radio telescopes will require technological advances from the communications industry interference from sources such as satellites and mobile phones is a serious concern. In addition to the fact that the level of interference is growing constantly the increased capabilities of next generation instruments make them more prone to harmful interference. These facilities must have mechanisms to allow operation in a crowded spectrum. In this report some of the factors which may limit the effectiveness of these mechanisms are investigated. Radio astronomy is unique among other observing wavelengths in that the radiation can be fully sampled at a rate which completely specifies the electromagnetic environment. Knowledge of phases and antennae gain factors affords one the opportunity to attempt to mitigate interference from the astronomical data. At present several interference mitigation techniques have been demonstrated to be extremely effective. However the observational scales of the new facilities will push the techniques to their limits. Processes such as signal decorrelation varying antenna gain and instabilities in the primary beam will have a serious effect on some of the algorithms. In addition the sheer volume of data produced will render some techniques computationally and financially impossible.

Mitchell, Daniel A.; Robertson, Gordon J.; Sault, Robert J.

284

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

285

The Sardinia Radio Telescope  

NASA Astrophysics Data System (ADS)

We describe the Sardinia Radio Telescope (SRT), a new general purpose, fully steerable antenna of the National Institute for Astrophysics. The radio telescope is under construction near Cagliari (Sardinia). With its large aperture (64m diameter) and its active surface, SRT is capable of operations up to ˜100GHz, it will contribute significantly to VLBI networks and will represent a powerful single-dish radio telescope for many science fields. The radio telescope has a Gregorian optical configuration with a supplementary beam-waveguide (BWG), which provides additional focal points. The Gregorian surfaces are shaped to minimize the spill-over and standing wave. After the start of the contract for the radio telescope structural and mechanical fabrication in 2003, in the present year the foundation construction will be completed. The schedule foresees the radio telescope inauguration in late 2006.

Grueff, G.; Alvito, G.; Ambrosini, R.; Bolli, P.; D'Amico, N.; Maccaferri, A.; Maccaferri, G.; Morsiani, M.; Mureddu, L.; Natale, V.; Olmi, L.; Orfei, A.; Pernechele, C.; Poma, A.; Porceddu, I.; Rossi, L.; Zacchiroli, G.

286

American RadioWorks  

NSDL National Science Digital Library

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

287

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

288

Radio Link Frequency Assignment  

Microsoft Academic Search

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

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

1999-01-01

289

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

290

Radio-Locator  

NSDL National Science Digital Library

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

2006-11-14

291

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.

292

A new digital land mobile satellite system  

NASA Technical Reports Server (NTRS)

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

Schneider, Philip

1990-01-01

293

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

Microsoft Academic Search

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

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

2010-01-01

294

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

Microsoft Academic Search

We report the results of simultaneous observations of the Vela pulsar in\\u000aX-rays and radio from the RXTE satellite and the Mount Pleasant Radio\\u000aObservatory in Tasmania. We sought correlations between the Vela's X-ray\\u000aemission and radio arrival times on a pulse by pulse basis. At a confidence\\u000alevel of 99.8% we have found significantly higher flux density in Vela's

A. Lommen; J. Donovan; C. Gwinn; Z. Arzoumanian; A. Harding; M. Strickman; R. Dodson; P. McCulloch; D. Moffett

2006-01-01

295

STEM on the radio  

NASA Astrophysics Data System (ADS)

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

Showstack, Randy

2011-10-01

296

Building corporate associations: Consumer attributions for corporate socially responsible programs  

Microsoft Academic Search

Corporate social responsibility (CSR) is often used as a key criterion in gauging corporate reputation. This research examined\\u000a the influence of consumers’ attributions on corporate outcomes in response to CSR. Researchers and managers have considered\\u000a consumers’ beliefs about CSR initiatives to be simplistic, serving either economic ends or reflecting sincere social concerns.\\u000a The results of two studies established that consumers’

Pam Scholder Ellen; Deborah J. Webb; Lois A. Mohr

2006-01-01

297

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.

298

75 FR 10439 - Cognitive Radio Technologies and Software Defined Radios  

Federal Register 2010, 2011, 2012, 2013

...10-12] Cognitive Radio Technologies and Software Defined Radios AGENCY: Federal Communications...proceeding concerning the use of open source software to implement security features in software defined radios (SDRs). While, the...

2010-03-08

299

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.

300

Radio Frequency Interference and the National Radio Astronomy Observatory  

NASA Astrophysics Data System (ADS)

Radio frequency interference (RFI) and radio astronomy have been closely linked since the emergence of radio astronomy as a scientific discipline in the 1930s. Even before the official establishment of the National Radio Astronomy Observatory, protection against contemporary and future radio noise levels was seen as crucial to ensure success of any new observatory. My talk will examine the various local, regional, national, and international efforts enacted to protect NRAO and other American radio astronomy sites from RFI.

Smith, Sierra

2014-01-01

301

Corporate Governance and Competition Policy  

Microsoft Academic Search

Corporate Governance and Competition Policy\\u000aSpencer Weber Waller\\u000aAbstract\\u000aCorporate governance law addresses the misaligned incentives between officers and directors of publicly-owned companies and their shareholders, and how this can lead to the destruction of shareholder value. Antitrust law governs the interaction between corporations and other economic actors in the marketplace and prohibits and penalizes anticompetitive agreements, unilateral conduct which

Spencer Weber Waller

2011-01-01

302

International Finance Corporation  

NSDL National Science Digital Library

As a part of the World Bank, the stated vision of the International Finance Corporation (IFC) is "that poor people have the opportunity to escape poverty and to improve their lives." To whit, the IFC works to promote open and competitive markets in developing countries, generate productive jobs and deliver basic services, among other things. First-time visitors will find that the layout of the site is visually stimulating and quite user-friendly. Visitors can use the embedded search engine to look for specific materials of interest.

303

New television services on broadcasting satellites  

NASA Astrophysics Data System (ADS)

The 1983 Regional Administrative Radio Conference (RARC) has made major decisions on the usefulness of the 12 GHz band for direct broadcasting via satellites in Region 2 (North, Central, and South America). The planning conference adopted technical parameters such as satellite powers and bandwidth, and orbital separation between satellites which guarantees high performance of the channels to each administration in the Region. A Direct Broadcast Satellite (DBS) transmission format has been designed which takes account of present and future needs for video, audio, and data services. Attention has been given to the achievement of high quality in a low-cost receiver. A multiplexed analog component (MAC) format eliminates cross-color, cross-luminance, while four channels of high-quality audio are provided.

Bouchard, M.; Lucas, K.

304

Satellite systems requirements for land mobile communications  

NASA Technical Reports Server (NTRS)

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

Horstein, M.

1983-01-01

305

Forecast impact experiment with GPS radio occultation measurements  

Microsoft Academic Search

Refractivity profiles from CHAMP GPS radio occultation measurements have been assimilated into the Met Office numerical weather prediction (NWP) system. A forecast impact experiment was run using 16 days of CHAMP data from May\\/June 2001, in addition to conventional and satellite observations which are used in operational forecasts. Although typically only 160 CHAMP profiles are assimilated daily, it is demonstrated

S. B. Healy; A. M. Jupp; C. Marquardt

2005-01-01

306

New Developments in Radar and Radio Sensors for Aircraft Navigation  

Microsoft Academic Search

Recent developments in airborne Doppler and ground mapping navigation radars and ground and satellite based radio systems are described. Simultaneous lobing and slope tracking techniques can remove the well-known Doppler sea bias error in fast and slowly moving vehicles. Doppler velocity information can be extracted from coherent forward-looking mapping radars, and high position fixing accuracy can be achieved by synthetic

WALTER R. FRIED

1974-01-01

307

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

308

Radio Reflection by Free Radicals in Earth's Atmosphere.  

PubMed

Reflections of megacycle-per-second radio signals by free radicals in Earth's ionosphere are observed having about the intensity predicted for induced magnetic-dipole transitions. It seems that magnetic atoms, ions, and molecules in planetary atmospheres may be detected by this method. These cbservations were made with the topside ionosonder of the Canadian satellite Alouette II. PMID:17813036

Barry, J D; Coleman, P J; Libby, W F; Libby, L M

1967-06-30

309

Cassini Radio Science Observations of Density Waves in Saturn's Rings  

Microsoft Academic Search

Saturn's ring system is an elegant celestial mechanical laboratory for studying the interactions between a host of small and large moons, and the rings themselves. Resonances between the satellites and the ring particles result in spiral density waves whose detailed characteristics can be used to determine the physical properties of the rings. Over the past year, the Cassini Radio Science

C. A. McGhee; R. G. French; N. J. Rappaport; E. A. Marouf; R. Dawson; K. Stack

2006-01-01

310

OECD Principles of Corporate Governance  

NSDL National Science Digital Library

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

311

The Sardinia Radio Telescope  

Microsoft Academic Search

We describe the Sardinia Radio Telescope (SRT), a new general purpose, fully steerable antenna of the National Institute for Astrophysics. The radio telescope is under construction near Cagliari (Sardinia). With its large aperture (64m diameter) and its active surface, SRT is capable of operations up to ˜100GHz, it will contribute significantly to VLBI networks and will represent a powerful single-dish

G. Grueff; G. Alvito; R. Ambrosini; P. Bolli; N. D'Amico; A. Maccaferri; G. Maccaferri; M. Morsiani; L. Mureddu; V. Natale; L. Olmi; A. Orfei; C. Pernechele; A. Poma; I. Porceddu; L. Rossi; G. Zacchiroli

2004-01-01

312

The Sardinia Radio Telescope  

Microsoft Academic Search

We present the status of the Sardinia Radio Telescope (SRT) project, a new general purpose, fully steerable 64 m diameter parabolic radio telescope under construction in Sardinia. The instrument is funded by Italian Ministry of University and Research (MIUR), by the Sardinia Regional Government (RAS), and by the Italian Space Agency (ASI), and it is charge to three research structures

Nichi D’Amico

2011-01-01

313

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

314

Lunar Farside Radio Lab  

Microsoft Academic Search

It is proposed that the Farside of the Moon should be protected legally against man-made radio pollution and uncontrolled exploitation. In fact, only by establishing a radiotelescope on the Farside of the Moon it will finally be possible to cope with the Radio Frequency Interference (RFI) that is now increasingly plaguing all of Radioastronomy, Bioastronomy and Search for Extraterrestrial Intelligence

Claudio Maccone

2005-01-01

315

Radio astronomy receivers  

Microsoft Academic Search

A general survey of the principles of radio astronomy receivers is presented. System noise temperature, the sensitivity of different receiver types, and the calibration of receivers are studied. A total-power receiver is analyzed as a basic radio telescope receiver and the results are used to obtain the performance of other receiver types such as the Dicke receiver, Graham's receiver, correlation

M. Tiuri

1964-01-01

316

Stabilized radio frequency quadrupole  

DOEpatents

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

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

1984-01-01

317

Satellite-aided land mobile communications system implementation considerations  

NASA Technical Reports Server (NTRS)

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

Leroy, B. E.

1982-01-01

318

Modems for emerging digital cellular-mobile radio system  

NASA Technical Reports Server (NTRS)

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

Feher, Kamilo

1991-01-01

319

Development of SELENE small sub-satellites: Rstar and Vstar for lunar gravity field observation  

Microsoft Academic Search

Two small sub-satellites Relay Satellite Rstar and VLBI Radio Satellite Vstar which are separated from SELENE Main Orbiter will execute four-way Doppler measurements and differential VLBI observation to make global mapping of the lunar gravity field These sub-satellites are requested to be simply structured light weighted and optimized for the selenodesy mission We have therefore adopted spin stabilization without thrusters

T. Iwata; H. Minamino; N. Namiki; H. Hanada; N. Kawano; T. Takano

2006-01-01

320

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

321

Corporate environmental disclosure, corporate governance and earnings management  

Microsoft Academic Search

Purpose – The purpose of this paper is to examine the association between corporate environmental disclosure (CED) and earnings management (EM) and the impact of corporate governance (CG) mechanisms on that association. Design\\/methodology\\/approach – The paper uses performance-matched discretionary accruals (DA) as a measure of EM. The paper also uses ordinary least square regression with robust standard errors to examine

Nan Sun; Aly Salama; Khaled Hussainey; Murya Habbash

2010-01-01

322

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

323

25 CFR 227.6 - Corporations and corporate information.  

Code of Federal Regulations, 2011 CFR

...LANDS IN WIND RIVER INDIAN RESERVATION, WYOMING, FOR OIL AND GAS MINING How to Acquire Leases § 227.6 Corporations and corporate...associations such individual stockholders are interested in mining leases on restricted lands within the state, and whether...

2011-04-01

324

Petite Amateur Navy Satellite (PANSAT)  

NASA Technical Reports Server (NTRS)

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

1989-01-01

325

Satellite Power Systems (SPS) concept definition study, exhibit F  

NASA Technical Reports Server (NTRS)

Preliminary technical data were derived for three new system satellite concepts. The concepts are: a geo-solar array and antenna with free-flying geo-solar reflector; a geo-solar array and antenna with free-flying geo-radio-frequency reflector; and a sun-synchronous solar array and antenna with free-flying geo-radio-frequency reflector. Parametric data are provided on microwave sidelobe reduction as a function of design changes.

Hanley, G. M.

1981-01-01

326

Sensitivity analysis for airborne sounding of the troposphere by GNSS radio occultation  

Microsoft Academic Search

The usual geometry for radio occultation sounding using global navigation satellite system (GNSS) signals has the receiver placed on a low earth orbit (LEO) satellite. We investigate a new geometric approach, assuming an airborne rather than a spaceborne receiver. Information on the refractivity structure and hence the pressure, temperature, and humidity can be retrieved from accurate airborne measurements of amplitude

O. Lesne; J. Haase; G. Kirchengast; J. Ramsauer; W. Poetzi

2002-01-01

327

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

328

Radio Science Concepts for Exploring the Interior Structures of Jupiter's Icy Moons  

Microsoft Academic Search

A set of concepts are proposed for the Jupiter Icy Moons Orbiter (JIMO) to apply Radio Science tools to investigate the interior structures of the Galilean Satellites and address key questions on their thermal and dynamical evolution. Multi-frequency Doppler tracking and ranging of the orbiter can be used to measure the gravity harmonic coefficients of the satellites as well as

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

2003-01-01

329

Propagation considerations in the American Mobile Satellite system design  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

330

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)] [Los Alamos National Lab., NM (United States)

1995-04-15

331

Broadcasting satellite feeder links - Characteristics and planning  

NASA Technical Reports Server (NTRS)

The paper presents the results of recent studies by the Feeder Link Sub-Working Group of the FCC Advisory Committee for the 1983 Regional Administrative Radio Conference (RARC). These studies conclude that specification of a few key parameters will make feeder link planning relatively straightforward. Feeder links can be located anywhere within a country if satellite orbit locations are separated by 10 deg for adjacent service areas and key parameter values presented in the paper are adopted. Colocated satellites serving a common service area need special attention to attain sufficient isolation between a desired channel and its adjacent cross-polarized channels and alternate co-polarized channels. In addition to presenting planning conclusions by the Advisory Committee, the paper presents and analyzes actions of the International Radio Consultative Committee's Conference Planning Meeting (CPM) concerning feeder links. The CPM reached conclusions similar to, and compatible with, those of the Advisory Committee.

Kiebler, J. W.

1982-01-01

332

Satellite altimetry  

NASA Technical Reports Server (NTRS)

Since altimetry data are not really old enough to use the term data archaeology, Mr. Cheney referred to the stewardship of these data. He noted that it is very important to document the basis for an altimetry data set as the algorithms and corrections used to arrive at the Geophysical Data Record (GDR) have been improving and are continuing to improve the precision of sea level data derived from altimetry. He noted that the GEOSAT Exact Repeat Mission (ERM) data set has recently been reprocessed by his organization in the National Ocean Service of NOAA and made available to the scientific community on CD/ROM disks by the National Oceanographic Data Center of the U.S. (NODC). The new data set contains a satellite orbit more precise by an order of magnitude together with an improved water vapor correction. A new, comprehensive GDR Handbook has also been prepared.

Cheney, Robert E.

1992-01-01

333

Theory "W": The Corporate Warrior.  

ERIC Educational Resources Information Center

Describes power structure of corporations functioning under Theory W in which single leaders, in partnership with trusted followers, achieve corporate success. Basis of this industrial structure is attributed to social and developmental structures of prehistoric man and city states. Dimensions of W, X, Y, and Z theories are discussed. (MBR)

Morris, David J., Jr.

1986-01-01

334

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

335

Corporate Memory Management through Agents  

Microsoft Academic Search

The CoMMA project (Corporate Memory Management through Agents) aims at developing an open, agent-based platform for the management of a corporate memory by using the most advanced results on the technical, the content, and the user interaction level. We focus here on methodologies for the set-up of multi-agent systems, requirement engineering and knowledge acquisition approaches.

Philippe PEREZ; Rose DIENG; Olivier CORBY; Fabien GANDON INRIA; Joel QUINQUETON LIRMM; Agostino POGGI; Giovanni RIMASSA; Claudio FIETTA CSELT; Juergen MUELLER; Joachim HACKSTEIN T-Nova

2000-01-01

336

Corporate portal as security backbone  

Microsoft Academic Search

Network topologies found in audits and reviews are not capable to fulfill the needs of security and flexibility. Specialized networks and protection systems increase the complexity and reduce the overall security. Central corporate portals can be used as IT-security backbones. Constructing the corporate portals with reverse-proxy technology and with internal firewalls will secure, that no connection to sensible data or

U. Maurer

2005-01-01

337

Low cost satellite land mobile service for nationwide applications  

NASA Technical Reports Server (NTRS)

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

Weiss, J. A.

1978-01-01

338

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.

339

Observations of Scintillations of Two Satellite Beacons near the Boundary of the Irregularity Region.  

National Technical Information Service (NTIS)

By using observations of the scintillations of two synchronous satellite beacons, ATS-3 and Intelsat 2F-3, from the Sagamore Hill Radio Observatory, comparisons could be made for ionospheric characteristics at the boundary of the high latitude irregularit...

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

1972-01-01

340

Synchronous Satellite Navigation on Large Regions of the Earth's Surface and in Near Earth Space.  

National Technical Information Service (NTIS)

The article discusses radio positioning navigational systems inside and outside China as well as the general status of development and performance characteristics associated with two generations of global satellite positioning navigational systems. It int...

Z. Xiaojun

1995-01-01

341

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

342

76 FR 79531 - Corporate Credit Unions  

Federal Register 2010, 2011, 2012, 2013

...WAL limits for corporate loan and investment...also require each corporate to test those...periodically for compliance. NCUA intended...quarter, for compliance with this WAL...life (WAL) of a corporate credit...

2011-12-22

343

76 FR 54991 - Corporate Credit Unions  

Federal Register 2010, 2011, 2012, 2013

...WAL limits for corporate loan and investment...and require each corporate to test those...periodically for compliance. 12 CFR 704...quarter, for compliance with this WAL...life (WAL) of a corporate credit...

2011-09-06

344

76 FR 23861 - Corporate Credit Unions  

Federal Register 2010, 2011, 2012, 2013

...an assessment of the corporate's compliance with such laws and regulations...an assessment of the corporate's compliance with certain laws and...by management of the corporate credit union's compliance with such laws and...

2011-04-29

345

Corporate U. Takes the Job Training Field.  

ERIC Educational Resources Information Center

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

Greenberg, Richard

1998-01-01

346

75 FR 73000 - Corporate Credit Unions  

Federal Register 2010, 2011, 2012, 2013

...asset-liability management controls; amend some corporate governance provisions; and limit a corporate CUSO to categories...c)(3) IPA's Reports Consistent with good corporate governance, proposed paragraph (c)(3) requires a...

2010-11-29

347

Array Signal Processing for Radio Astronomy  

NASA Astrophysics Data System (ADS)

Radio astronomy forms an interesting application area for array signal processing techniques. Current synthesis imaging telescopes consist of a small number of identical dishes, which track a fixed patch in the sky and produce estimates of the time-varying spatial covariance matrix. The observations sometimes are distorted by interference, e.g., from radio, TV, radar or satellite transmissions. We describe some of the tools that array signal processing offers to filter out the interference, based on eigenvalue decompositions and factor analysis, which is a more general technique applicable to partially calibrated arrays. We consider detection of interference, spatial filtering techniques using projections, and discuss how a reference antenna pointed at the interferer can improve the performance. We also consider image formation and its relation to beamforming.

Veen, Alle Jan; Leshem, Amir; Boonstra, Albert Jan

2004-06-01

348

Satellite sound broadcast propagation measurements and system impairments  

NASA Astrophysics Data System (ADS)

An evaluation of the operational characteristics of indoor portable reception of satellite sound reception has identified the nature of UHF and L-band signals' penetration loss in the cases of buildings having intricate spectral and spatial signal structures. These propagation impairments must be mitigated by resort to a combination of link margin, diversity techniques, and/or the efforts of a listener to place the radio (or its antenna) in an advantageous location. Attention is given to cost/performance tradeoffs for a mix of these measures, with a view to Direct Broadcast Satellite Radio system design.

Vogel, Wolfhard J.; Torrence, Geoffrey W.; Golshan, Nasser

1992-03-01

349

Satellite sound broadcast propagation measurements and system impairments  

NASA Technical Reports Server (NTRS)

An evaluation of the operational characteristics of indoor portable reception of satellite sound reception has identified the nature of UHF and L-band signals' penetration loss in the cases of buildings having intricate spectral and spatial signal structures. These propagation impairments must be mitigated by resort to a combination of link margin, diversity techniques, and/or the efforts of a listener to place the radio (or its antenna) in an advantageous location. Attention is given to cost/performance tradeoffs for a mix of these measures, with a view to Direct Broadcast Satellite Radio system design.

Vogel, Wolfhard J.; Torrence, Geoffrey W.; Golshan, Nasser

1992-01-01

350

Radio interference in the near-earth environment  

NASA Technical Reports Server (NTRS)

Natural and man-made radio frequency interference (RFI) are potentially serious obstacles to the successful operation of an array of spacecraft used for low frequency (1 to 30 MHz) radio interferometry in the near-earth environment. Several satellites and planetary probes have carried radio astronomy experiments, and the moderate data base that they provide are examined to help understand the near-earth RFI environment. The general conclusion is that the region of space within 100 earth-radii of the earth is a hostile environment for any radio astronomy experiment. If a low frequency array in earth orbit is to yield useful astronomical results, severe interference problems must be anticipated and overcome. A number of recommendations are made to further examine the feasibility of such an array.

Erickson, W. C.

1988-01-01

351

Outer planet satellites  

NASA Technical Reports Server (NTRS)

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.

Schenk, Paul M.

1991-01-01

352

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. Then students learn general concepts about magnetic fields, leading into how radio waves are created and transmitted. Several demonstrations are performed to help students better understand these concepts. The lesson goal is for students to comprehend how the AM radios they will build during the associated activity function.

Techtronics Program

353

Modeling of radio meteors  

SciTech Connect

A modified version of a computer model of radio meteors, based on empirical data for the arrival of meteoric material in circumterrestrial space, is presented. Good agreement with the experimental data for the Moscow-Kazan radio link is obtained. Results of calculations of the angular sizes of the reflection area for the St. Petersburg-Kazan radio link are presented. The reflection area is shown to be a sufficiently compact object with angular sizes 34.6{degrees}{+-}2.1{degrees} in the azimuthal plane and 12.7{degrees}{+-}1.2{degrees} in the vertical plane.

Karpov, A.V.; Sidorov, V.V.; Tereshin, S.N. [Kazan State Univ., Tatarstan (Russian Federation)

1995-11-01

354

Rural Community Assistance Corporation  

NSDL National Science Digital Library

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

355

The performance of a satellite link using the BBC Transportable Earth Station with EBU-leased capacity in the European Communication Satellite System  

NASA Astrophysics Data System (ADS)

A series of tests on a satellite link established between the British Broadcasting Corporation (BBC) Transportable Satellite Earth Station and a BTI fixed earth station using an EBU-leased transponder on the European Communication Satellite (ECS) 2 satellite are described. The transmitted power was limited to comply with new regulations imposed by the satellite operator, but the results indicate that a high quality television link can still be established over a potential coverage area which includes most of Europe. Also, under these conditions an adequate fading margin is obtained for all but 1.75 hours per year.

Gandy, C.

1985-11-01

356

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

357

Radio-optical alignments in a low radio luminosity sample  

Microsoft Academic Search

We present an optically based study of the alignment between the radio axes and the optical major axes of eight z~0.7 radio galaxies in a 7C sample. The radio galaxies in this sample are ~20 times less radio-luminous than 3C galaxies at the same redshift, and are significantly less radio-luminous than any other well-defined samples studied to date. Using Nordic

Mark Lacy; Susan E. Ridgway; Margrethe Wold; Per B. Lilje; Steve Rawlings

1999-01-01

358

Preliminary validation efforts of GRAS radio occultation data recorded in raw-sampling mode  

Microsoft Academic Search

Atmospheric remote soundings of tropo-\\/stratospheric temperature profiles by the GNSS (Global Navigation Satellite System) radio occultation (RO) method provide valuable input for numerical weather prediction models and climate change studies. The RO-instrument GRAS (GNSS Receiver for Atmospheric Sounding) on-board of EUMETSAT's (European Organisation for the Exploitation of Meteorological Satellites) MetOp satellite has been designed for observing setting and rising occultations

Florian Zus; Christian Marquardt; Magnus Bonnedal

2010-01-01

359

Variational data assimilation for deriving global climate analyses from GNSS radio occultation data  

Microsoft Academic Search

A comprehensive global navigation satellite system (GNSS) based radio occultation (RO) data set is available for meteorology\\u000a and climate applications since the start of GNSS RO measurements aboard the CHAllenging Mini-satellite Payload (CHAMP) satellite\\u000a in February 2001. Global coverage, all-weather capability, long-term stability and accuracy not only makes this innovative\\u000a use of GNSS signals a valuable supplement to the data

A. Löscher; G. Kirchengast

2008-01-01

360

Inexpensive Megabit Packet Radio System.  

National Technical Information Service (NTIS)

Although packet radio is relatively new to the amateur radio community, there are now over 10,000 amateur packet radio units in service. These units cost between $500 and $800, including the controller and radio, and generally operate at 1200 baud. An eff...

R. Bisbey R. Parker R. Cole

1986-01-01

361

BEA Symposium: Research in Radio.  

ERIC Educational Resources Information Center

The seven articles in this journal issue examine trends and topics related to radio and other broadcast media. The articles discuss the following: (1) current trends in radio audience measurement, (2) the policy implications of radio research, (3) a research study of the relationships between age and radio usage, (4) the role of the part-time…

Finney, Robert G., Ed.; Neckowitz, Alan, Ed.

1980-01-01

362

The Sardinia Radio Telescope  

NASA Astrophysics Data System (ADS)

We present the status of the Sardinia Radio Telescope (SRT) project, a new general purpose, fully steerable 64 m diameter parabolic radio telescope under construction in Sardinia. The instrument is funded by Italian Ministry of University and Research (MIUR), by the Sardinia Regional Government (RAS), and by the Italian Space Agency (ASI), and it is charge to three research structures of the National Institute for Astrophysics (INAF): the Institute of Radio Astronomy of Bologna, the Cagliari Astronomical Observatory (in Sardinia), and the Arcetri Astrophysical Observatory in Florence. The radio telescope has a shaped Gregorian optical configuration with a 8 m diameter secondary mirror and additional Beam-Wave Guide (BWG) mirrors. One of the most challenging feature of SRT is the active surface of the primary reflector which provides good efficiency up to about 100 GHz. This paper reports on the most recent advances of the construction.

D'Amico, Nichi

2011-08-01

363

Broadcast Radio Service.  

National Technical Information Service (NTIS)

The tape contains data for applicants and licensees operating radio equipment approved by the Federal Communications Commission. Data records include station and license identification, location, radiofrequency, mailing address (all items do not contain c...

J. J. Sharkey

1974-01-01

364

General Radio Service.  

National Technical Information Service (NTIS)

The tape contains data for applicants and licensees operating radio equipment approved by the Federal Communications Commission. Data records include station and license identification, location, radiofrequency, mailing address (all items do not contain c...

J. J. Sharkey

1974-01-01

365

Broadcast Auxiliary Radio Service.  

National Technical Information Service (NTIS)

The tape contains data for applicants and licensees operating radio equipment approved by the Federal Communications Commission. Data records include station and license identification, location, radiofrequency, mailing address (all items do not contain c...

J. J. Sharkey

1974-01-01

366

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

NASA Technical Reports Server (NTRS)

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

Miller, E. F.

1986-01-01

367

Properties of SELENE Small Satellites for Selenodetic Measurements: Rstar (OKINA) and Vstar (OUNA)  

NASA Astrophysics Data System (ADS)

SELENE Main Orbiter (KAGUYA) has separated two small sub-satellite (1) the Relay Satellite “Rstar (OKINA)”, and (2) the VLBI Radio Satellite “Vstar (OUNA)”. These sub-satellites started to perform 4-way Doppler measurements using Relay Satellite Transponder (RSAT) and multi frequency differential VLBI using VLBI Radio Sources (VRAD) for selenodesy. Initial check out was executed and properties of satellite bus equipments, onboard mission instruments, and observation systems including ground stations were evaluated. Electric power and thermal control subsystems have shown that they conduct as designed and inspected in the ground tests. The release mechanisms have given the spin which can maintain the stability of the satellite attitudes. Communication functions of mission instruments conform to the link budgets. These results suggest that Rstar and Vstar have enough performances to produce efficient selenodetic data by RSAT/VRAD observations.

Iwata, Takahiro; Namiki, Noriyuki; Hanada, Hideo; Noda, Hirotomo; Kawano, Nobuyuki; Matsumoto, Koji; Tsuruta, Seiitsu; Liu, Qinghui; Kikuchi, Fuyuhiko; Minamino, Hiroyuki; Sasaki, Takeshi

368

The allocation of the radio spectrum  

NASA Astrophysics Data System (ADS)

The system of the radio spectrum (10 kHz-300 GHz) allocation is discussed in its technical, economic, and managerial aspects. Possible improvements to the system are considered, such as minimizing human management, establishing a single authority for the allocation of the spectrum, and stimulating a more efficient use of the spectrum with economic incentives. The 'anarchy band' concept, a system of dynamic allocation, is suggested as a means of replacing human management with electronic equipment. The growing importance of the satellite portion of the spectrum is also shown.

Jackson, C. L.

1980-02-01

369

Burst interference in TDMA radio systems  

NASA Astrophysics Data System (ADS)

Burst interference is inherent in TDMA subscriber radio and satellite communications systems. Spectral and interference properties of burst modulated signals are investigated. Owing to the burst mode operation of the TDMA system its spectrum spreads; this spread increases with the increase of burst gating rate and the decrease of the burst length. A theoretical derivation of the Pe = f(Eb/N0; I) performance, computer simulation and experimental results of IJF-OQPSK and conventional QPSK burst operated systems are presented. The performance of these systems in the presence of burst mode TDMA co-channel and adjacent channel interference (I) is evaluated.

Lei, Z.; Chen, M.-X.; Feher, K.

1985-12-01

370

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 weather…

Summers, R. Joe; Gotwald, Timothy

371

Radio Telescope Design  

Microsoft Academic Search

\\u000a This is an important chapter concerning radio telescope design. In the first part of this chapter, all the major design issues\\u000a of radio telescopes are discussed, which include the reflector surface transmission loss, the antenna tolerance theory, the\\u000a antenna homology design, the antenna surface best fitting, the antenna component positional tolerance, the antenna aperture\\u000a blockage, the ground radiation pick-up, and

Jingquan Cheng

372

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

373

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

ERIC Educational Resources Information Center

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

Krause, Lloyd I.

374

An overview of satellite transmission issues and the ISDN  

NASA Astrophysics Data System (ADS)

Satellite communications are examined in terms of services, flexibility, connectivity, and quality. Present business communications services and the need for a corporate communication network are discussed. The development of an integrated services digital network (ISDN) is proposed; the capabilities and advantages of ISDN are described. Consideration is given to the interconnectibility of ISDN and methods for improving transmission quality.

Knight, Ivor N.; Neibert, Mark T.

375

IMAGE Satellite Scaling  

NSDL National Science Digital Library

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

376

The provision of mobile satellite services in Canada  

NASA Astrophysics Data System (ADS)

Telesat Mobile Inc. (TMI) is a private company authorized to provide mobile satellite services in Canada. TMI will operate a dedicated MSAT satellite to provide mobile telephone, mobile radio and mobile data services to customers on the move in any part of Canada. The baseline TMI system is described in this paper. The network architecture and the signaling system under development to support the mobile services are discussed. The time-scale for procurement of the system is discussed.

Davies, N. G.; Roscoe, O. S.

1990-05-01

377

Propagation aspects of ISDN satellite links above 10 GHz  

NASA Astrophysics Data System (ADS)

A model is introduced for dealing with the latest CCITT criteria for the design of single, 64 Kb/s uncoded digital Fixed Satellite Service (FSS) channels below 15 GHz radio frequency. The Stored Channel concept, known from the area of mobile satellite communications is presented as a suitable approach for performing simultaneous BER and a fade measurements to verify the model at frequencies above 10 GHz while employing various transmission rates, channel codes, and multiplexing schemes.

Hendrickx, M. P. M.

378

25 CFR 227.6 - Corporations and corporate information.  

Code of Federal Regulations, 2013 CFR

...227.6 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF CERTAIN LANDS IN WIND RIVER INDIAN RESERVATION, WYOMING, FOR OIL AND GAS MINING How to Acquire Leases § 227.6 Corporations and...

2013-04-01

379

Satellite outreach in Asia and the Pacific.  

PubMed

Communication by satellite is rapidly changing information exchange in Asia, especially for rural areas. The integrated education planned for satellite networks includes family planning as part of general development. A series of conferences has already been held successfully via satellite for family planning associations who are members of the East and Southeast Asia and Oceania Region of the International Planned Parenthood Federation. These included a conference on nursing training. In India the Satellite Instructional Television Experiment (SITE) made history during its 1-year trial. By 1981 the entire nation is to be linked by satellite. The question is whether the television education will truly change rural life or whether it will become merely a diversion. In Indonesia, satellites were chosen as the fastest way to obtain interisland communication. The Domsat system links the entire 13,000-island archipelago and is already being used for emergency communications. The system, which was developed in 1 1/2 years by the Hughes Aircraft Corporation will be used for teaching basic health, hygiene, and family planning. It will be several years before Domsat is fully operational, but it bears watching. PMID:12260108

1977-01-01

380

Extragalactic Radio Jets and Intergalactic Medium 2  

NASA Technical Reports Server (NTRS)

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

Birkinshaw, Mark

2000-01-01

381

Orbit modelling for satellites using the NASA prediction bulletins  

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

382

Radio Variability of Radio-quiet and Radio-loud Quasars  

NASA Astrophysics Data System (ADS)

The majority of quasars are weak in their radio emission, with flux densities comparable to those in the optical, and energies far lower. A small fraction, about 10%, are hundreds to thousands of times stronger in the radio. Conventional wisdom holds that there are two classes of quasars, the radio-quiets and radio-louds, with a deficit of sources having intermediate power. Are there really two separate populations, and if so, is the physics of the radio emission fundamentally different between them? This paper addresses the second question, through a study of radio variability across the full range of radio power, from quiet to loud. The VLA was used during 10 epochs to study three carefully selected samples of 11 radio-quiet quasars, 11 radio-intermediate quasars, and 8 radio-loud quasars. A fourth sample consists of 20 VLA calibrators used for phase correction during the observations, all of which are radio-loud. The basic findings are that the root mean square amplitude of variability is independent of radio luminosity or radio-to-optical flux density ratio and that fractionally large variations can occur on timescales of months or less in both radio-quiet and radio-loud quasars. Combining this with similarities in other indicators, such as radio spectral index and the presence of VLBI-scale components, leads to the suggestion that the physics of radio emission in the inner regions of all quasars is essentially the same, involving a compact, partially opaque core together with a beamed jet. It is possible that differences in large-scale radio structures between radio-loud and radio-quiet quasars could stem from disruption of the jets in low-power sources before they can escape their host galaxies.

Barvainis, Richard; Lehár, Joseph; Birkinshaw, Mark; Falcke, Heino; Blundell, Katherine M.

2005-01-01

383

Radio frequency observations of lightning discharges by the forte satellite.  

SciTech Connect

FORTE-observed VHF signatures for different lightning discharges are presented. For in-cloud discharges, a pulse pair is typically recorded and is named a 'transionospheric pulse pair' (TIPP). Many intense TIPPs are coherent and polarized, whereas initial and dart leaders do not show a recognizable degree of polarization. TIPPs are optically weaker than cloud-to-ground (CG) strokes, and stronger VHF TIPPs are optically darker. About 10% of CG strokes, mostly over seawater, produce extremely narrow, powerful VHF pulses at the very beginning of the return strokes. These narrow pulses are found to form an upward beam pattern.

Shao, X. (Xuan-Min); Jacobson, A. R.; Light, T. (Tracy E.); Suszcynsky, D. M. (David M.)

2002-01-01

384

Individual and Corporate Social Responsibility  

Microsoft Academic Search

Society's demands for individual and corporate social responsibility as an alternative response to market and distributive failures are becoming increasingly prominent. We first draw on recent developments in the \\

Roland Benabou; Jean Tirole

2009-01-01

385

A Concept of Corporate Memory.  

National Technical Information Service (NTIS)

This report describes a concept of 'corporate memory' which attempts to provide information systems support to the organization as a whole. It also examines the propositions that organizations incur higher information gathering costs than individuals and ...

H. L. Morgan D. J. Root

1979-01-01

386

Hot on the Corporate Trail  

ERIC Educational Resources Information Center

The key sources for public company information are annual reports, company reports published by Moody's Investors Service and Standard and Poor's Corporation, industry surveys, and periodical indexes. (Author/PF)

Truelson, Judith A.

1976-01-01

387

Satellite sound broadcasting system study: Mobile considerations  

NASA Technical Reports Server (NTRS)

Discussed here is the mobile reception part of a study to investigate a satellite sound broadcast system in the UHF or L bands. Existing propagation and reception measurements are used with proper interpretation to evaluate the signaling, coding, and diversity alternatives suitable for the system. Signal attenuation in streets shadowed by buildings appear to be around 29 db, considerably higher than the 10 db adopted by CCIR. With the marriage of proper technologies, an LMSS class satellite can provide substantial direct satellite audio broadcast capability in UHF or L bands for high quality mobile and portable indoor reception by low cost radio receivers. This scheme requires terrestrial repeaters for satisfactory mobile reception in urban areas. A specialized bandwidth efficient spread spectrum signalling technique is particularly suitable for the terrestrial repeaters.

Golshan, Nasser

1990-01-01

388

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

389

A Cooperative Approach to Corporate Memory Modeling  

Microsoft Academic Search

Nowadays, the importance of Knowledge Management is growing in organizational contexts. Corporate Memory is an appropriate tool to represent organizational knowledge. This work presents an ontology-based approach to Corporate Memory modeling. In it, the members of an organization act as 'knowledge builders' and they construct the Corporate Memory co- operatively. Furthermore, the employees who take part of the Corporate Memory

Jesualdo Tomás; Fernández Breis; Rodrigo Martínez-Béjar; Laura María Campoy-Gómez; Fernando Martín-Rubio; Juan José García-Martínez

390

Corporate Governance and Earnings Management  

Microsoft Academic Search

Abstract This study investigates whether a firm’s corporate governance practices have an effect onthe quality of its publicly released financial information. In particular, we examine the relationship between,audit committee,and board of directors characteristics and the extent of corporate,earnings ,management ,as measured ,by the ,level of positive ,and ,negative discretionary accruals. Using two groups of US firms, one with relatively high

Sonda Marrakchi Chtourou; Jean Bédard; Lucie Courteau

2001-01-01

391

Corporate Governance and Firm Diversification  

Microsoft Academic Search

We empirically investigate whether corporate governance structure is different between focused and diversified firms, and whether any differences in corporate governance are associated with the value loss from diversification. We find that, relative to focused firms, CEOs in diversified firms have lower stock ownership and lower pay-for-performance sensitivities. Diversified companies, however, have more outside directors, no difference in independent block-holdings,

Ronald C. Anderson; Thomas W. Bates; John M. Bizjak; Michael L. Lemmon

2000-01-01

392

Corporal punishment and child adjustment  

Microsoft Academic Search

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

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

2006-01-01

393

Corporate Governance and Business Ethics  

Microsoft Academic Search

\\u000a Corporate governance can be an important defense against unethical corporate behavior (Carcello 2009). For example, a firm’s\\u000a board of directors is responsible for overseeing firm management. If the board does not adequately perform this oversight,\\u000a then it may be easier for managers to behave unethically. In fact, Hoffman and Rowe (2007) report that various investigations\\u000a found that poor oversight of

Andrew J. Felo

394

Mashup-Aware Corporate Portals  

Microsoft Academic Search

\\u000a Unlike other Web applications, corporate portals reckon to provide an integration space for corporate services. Mashups contribute\\u000a to this goal by bringing a relevant customization technique whereby portal users can supplement portal services with their\\u000a own data needs. The challenge is to find a balance between portal reliability and mashup freedom. Our approach is to split\\u000a responsibilities between service providers

Sandy Pérez; Oscar Díaz

2010-01-01

395

Correlation between X-Ray Light-Curve Shape and Radio Arrival Time in the Vela Pulsar  

Microsoft Academic Search

We report the results of simultaneous observations of the Vela pulsar in X-rays and radio from the RXTE satellite and the Mount Pleasant Radio Observatory in Tasmania. We sought correlations between Vela's X-ray emission and radio arrival times on a pulse-by-pulse basis. At a confidence level of 99.8% we have found significantly higher flux density in Vela's main X-ray peak

A. Lommen; J. Donovan; C. Gwinn; Z. Arzoumanian; A. Harding; M. Strickman; R. Dodson; P. McCulloch; D. Moffett

2007-01-01

396

Applications of a corporate synergy system to promote cleaner production in small and medium enterprises  

Microsoft Academic Search

A Corporate Synergy System (CSS) is a management mechanism through which a group of manufacturing companies work together to achieve certain production or management goals. Established among firms in supply chains, a CSS usually consists of a central firm and its satellite manufacturing suppliers. The system is being adopted in Taiwan as the key mechanism for promoting cleaner production (CP)

Shen-yann Chiu; Jerry H. Huang; Chih-Sen Lin; Yi-hua Tang; Wen-huei Chen; Shen-Chia Su

1999-01-01

397

GEOSAT Follow-On Radar Altimeter Satellite Performance Studies  

NASA Astrophysics Data System (ADS)

Under a Navy Contract with Ball Aerospace and Technologies Corporation, the first GFO satellite was completed in 1997 and launched on 10 February 1998 on an Orbital Taurus launch vehicle. The satellite was operationally accepted on 29 November 2000. With an anticipated 8-year or more life, GFO (http://gfo.bmpcoe.org/Gfo) is a DoD satellite mission managed by the Space and Naval Warfare Systems Command's (SPAWAR's) Meteorological and Oceanographic (METOC) Systems Program Office (PMW 155) located in San Diego, California. The satellite is in the same Exact Repeat Orbit (ERO) as the original GEOSAT (800 km by 108 degrees inclination). All GFO's data products are available to the scientific community and are distributed by NOAA's Laboratory for Satellite Altimetry. The primary program objective was to develop an operational series of radar altimeter satellites to maintain continuous ocean observation for accurate global measurements of both mesoscale and basin-scale oceanography. Since its acceptance, Computer Sciences Corporation (CSC), under contract with the Navy, has provided a team known as the GFO Cal/Val and assisted by NASA and NOAA personnel has undertaken extensive and continuing calibration and validation activities on an exact repeat cycle basis. This paper will discuss the results of those Cal/Val efforts and present charts showing the performance history of the satellite, its sensors (both the Radar Altimeter and the Water Vapor Radiometer), and other relevant performance measures such as orbit accuracy.

Finkelstein, J. L.; Rau, M.; McMillan, J. D.

2002-12-01

398

BSA Radio Merit Badge  

NSDL National Science Digital Library

The radio merit badge is one of many elective merit badges a Boy Scout can earn while on his path to completing the rank of Eagle Scout. One of the purposes of this merit badge is to inform, educate, and train Scouts in radio communication. It is also designed to help each young man develop additional skills and increase their enjoyment and expand their adventures. This instructional module is aimed at providing a structured beginning to any Boy Scout wishing to achieve the radio merit badge. This instruction in no way replaces the merit badge booklet of which I highly recommend reviewing while working through the requirement and a merit badge counselor; both of which are necessary in completing the requirement. I recommend that you contact your radio merit badge counselor for guidance and instruction prior to working through the requirements and beginning this instruction. OBJECTIVES: After completing this instructional module, you will have the knowledge base and skills to complete all the requirements of the Boy Scouts of America Radio Merit Badge. MATERIALS: To complete this learning activity, each student will need: Access to a computer with internet connection capabilities. A contact name and number of your nearest ...

Hjorten, Mr.

2006-02-03

399

The Smiley Radio Telescope  

NASA Astrophysics Data System (ADS)

More than ever modern astronomy is based upon a multi-wavelength approach combining data-sets from optical, infrared, radio, X-ray and gamma ray observatories to provide improved understanding of astrophysical phenomena. In the field of astronomy education however, until recently most teaching resources available to high schools have been limited to small optical telescopes, with little coverage of other branches of observational astronomy. To fill in this resource gap, PARI has developed the School of Galactic Radio Astronomy and the Smiley 4.6 m Radio Telescope to provide high schools access to a state-of-the-art, internet accessable radio observatory for class projects and activities. We describe here the development of the Smiley radio telescope, its control systems and give examples of several class activities which have been developed for use by high school students. We describe the future development of Smiley and plans to upgrade its performance. The SGRA has been supported by grants from Progress Energy, Z. Smith Reynolds, STScI IDEAS, and the AAS Small Research Grant Program which is supported by NASA.

Blake, R. M.; Castelaz, M. W.; Daugherty, J.; Owen, L.

2004-12-01

400

Broadband Satellite Systems  

Microsoft Academic Search

Recently, the interest in broadband satellite multimedia (BSM) systems has grown rapidly. Advancements in transmission technology have led to the availability of low-cost satellite earth terminals. The superior remote access capabilities of satellite networks are foreseen to provide broadband services to geographically diverse user groups. The desire to support a wide range of broadband services in satellite networks implies that

Daniel Jozef Bem; Tadeusz W. Wieckowski; Ryszard J. Zielinski

2000-01-01

401

The Satellites of Jupiter  

Microsoft Academic Search

The objective of this paper is to deduce the revolution of the four Galilean satellites and the distances of those satellites from Jupiter. Galileo discovered Jupiter's four largest satellites, Io, Callisto, Ganymede and Europa, in 1610 with a telescope that would be regarded by today's standard as rudimentary (Kaufmann & Freedman 1999). The Galilean satellites, as they were to be

RONALD E. MICKLE

1931-01-01

402

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

403

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

404

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

Microsoft Academic Search

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

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

2011-01-01

405

Potential radio frequency interference with the GPS L5 band for radio occultation measurements  

NASA Astrophysics Data System (ADS)

New Radio Occultation (RO) receivers are planned to utilize the newly implemented Global Positioning System (GPS) L5 signal centered at 1176.45 MHz. Since there are currently no operational GPS L5 receivers used for space-based RO applications, the interference environment is unclear. Distance Measuring Equipment (DME) and Tactical Air Navigation (TACAN) stations share the same frequency band as the GPS L5 signal. DME/TACAN signals have been identified to be a means of interference for any GPS L5 receiver. This study focuses on implementing a Systems Tools Kit (STK) simulation to gain insight into the power received by a RO satellite in Low Earth Orbit (LEO) from a DME/TACAN transmission. In order to confirm the validity of utilizing STK for communication purposes, a theoretical scenario was recreated as a simulation and the results were confirmed. Once the method was validated, STK was used to output a received power level aboard a RO satellite from a DME/TACAN station as well as a tool to predict the number of interfering DME/TACAN stations at any point in time. Taking a conservative approach, the signal power received was much greater than the typical power level received by a RO satellite from a GPS satellite transmission. This relatively high received power along with a high number of interfering DME/TACAN stations as an RO satellite passes over North America or Western Europe indicate that DME/TACAN interference may conflict with RO receivers.

Wolff, A. M.; Akos, D. M.; Lo, S.

2014-05-01

406

Projection method of sensing and interference areas of an earth observation satellite  

Microsoft Academic Search

A simple graphic display method for projecting remotely sensed areas of the earth and radio interference areas on a map using a microcomputer and an x-y plotter is presented. Transformation matrices are defined for Mercator, polar stereo, and Lambert projections of satellite imagery. Applications are illustrated in terms of an off-nadir viewing area, mapping a satellite visible area, and mapping

H. Sato; T. Igarashi; K. Tsuchiya

1982-01-01

407

A Satellite-Based System for Redundant Maritime Distress Signaling.  

National Technical Information Service (NTIS)

The loss of life and property in sudden maritime disasters represent a significant global problem. In many such disasters, no radio distress call is received. Emergency alerting via satellite is perceived as a cost-effective means of reducing the loss of ...

W. S. Scales

1978-01-01

408

Satellite Power System Concept Development and Evaluation Program  

Microsoft Academic Search

The progress made by the Concept Development and Evaluation Program (CDEP), set up to consider the Satellite Power System (SPS) program, is assessed. It is pointed out that from a technical standpoint the SPS concept now has at least two options for each of the following subsystems: conversion of solar energy to electrical energy; conversion of electrical energy to radio

F. A. Koomanoff; C. A. Sandahl

1980-01-01

409

Usage and protection of the earth exploration satellite service  

Microsoft Academic Search

Earth observations by microwave radiometers are typically performed at frequencies allocated for passive use to the Earth Exploration Satellite Service (EESS). Many of these allocations are shared with the Radio Astronomy Service (RAS) and are also often shared with generally compatible active services. The problem of RFI in spaceborne microwave radiometer data has been known since 1978 when it was

Jeffrey Piepmeier

2008-01-01

410

New American Radio  

NSDL National Science Digital Library

It's quite unusual that a long-defunct radio program would garner a new website, but this is the case with the New American Radio (NAR) show. During its 10-year run, NAR commissioned and distributed over 300 original works, including conceptual new drama works, language explorations, sonic meditations, and works that "pioneer new dimensions in acoustic space." On the site's homepage, visitors can peruse a list of full-length works, excerpts, and even a set of meditative essays on the creative process. A good work to start with here is "O Little Town of East New York" by Shelley Hirsch. It's a compelling autobiographical "docu-musical" about growing up in this diverse neighborhood in the 1960s. The site could be used by any number of students studying communication, drama, theater, radio production, and related subjects.

411

High redshift radio galaxies  

NASA Technical Reports Server (NTRS)

High redshift galaxies that host powerful radio sources are examined. An overview is presented of the content of radio surveys: 3CR and 3CRR, 4C and 4C/USS, B2/1 Jy, MG, MRC/1Jy, Parkes/PSR, B3, and ESO Key-Project. Narrow-line radio galaxies in the visible and UV, the source of ionization and excitation of the emission lines, emission-line luminosities, morphology of the line-emitting gas, physical properties and energetics, kinematics of the line-emitting gas, and implications from the emission lines are discussed. The morphologies and environments of the host galaxies, the alignment effect, and spectral energy distributions and ages are also examined.

Mccarthy, Patrick J.

1993-01-01

412

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

413

VHF radio scintillations at Bombay  

NASA Astrophysics Data System (ADS)

The simultaneous recordings of the amplitude scintillations of VHF radio signals from nearby geostationary satellites Fleetsat (at 73 deg E long.) and Sirio (at 65 deg E) received at Bombay (geog. lat. 19 deg N, geog. long. 73 deg E, mag. lat. 15 deg N) have revealed systematic time shifts in the starting and the ending of the individual scintillation events. The ionosphere crossover points of the two transmission paths were separated by only 80 km in the east-west direction, which was smaller than the average size of the irregularity patches. Scintillations normally started after 1930 h, reached a maximum at 2200 h, and slowly decreased until 1000 h, after which no scintillations were observed. The speed of the irregularity patches computed from the time shifts of these events was about 150 m/s in the early hours of the night, decreasing to about 100 m/s by midnight and showing much lower velocities in the post-midnight hours.

Koparkar, P. V.; Rastogi, R. G.

1985-10-01

414

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

415

Quad-Tree Visual-Calculus Analysis of Satellite Coverage  

NASA Technical Reports Server (NTRS)

An improved method of analysis of coverage of areas of the Earth by a constellation of radio-communication or scientific-observation satellites has been developed. This method is intended to supplant an older method in which the global-coverage-analysis problem is solved from a ground-to-satellite perspective. The present method provides for rapid and efficient analysis. This method is derived from a satellite-to-ground perspective and involves a unique combination of two techniques for multiresolution representation of map features on the surface of a sphere.

Lo, Martin W.; Hockney, George; Kwan, Bruce

2003-01-01

416

Developments in land mobile satellite service in Europe  

NASA Technical Reports Server (NTRS)

The evolution of land mobile radio has reached a stage to benefit from satellite communications. The provision of a service on a pan-European basis makes the use of satellites a viable proposition. The paper describes the European position on both system and space segment aspects of the land mobile satellite service. Also, some of the functions of the European institutions, such as the European Telecommunications Standards Institute (ETSI), the Conference of European Postal and Telecommunications Administrations (CEPT), and the Commission of European Communities (CEC), in establishing these services are identified.

Jayasuriya, D. A. R.

1990-01-01

417

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

418

Advances in Radio Telescopes  

NASA Astrophysics Data System (ADS)

The editors of the third Special Issue on Radio Telescopes, which appeared in the Proceedings of the IEEE in May 1994, surmised in their introduction that "perhaps yet a future issue is merited, one devoted to those new telescopes that are still on the drawing boards." Now, 15 years later, such an issue lies in front of you, featuring 16 papers describing both the realization of new instruments and the status of several giant radio telescopes, most of which are moving from the drawing board to different stages of construction. The development of astronomy over this period has led radio astronomers to concentrate on both the highest and the lowest ranges of the radio spectrum. The technological advance in the millimeter wavelength domain has enabled an enormous improvement in observing capabilities. In the low frequency range, roughly 10 - 2000 MHz, new telescopes are being planned that combine a large instantaneous field of view with a large number of high- resolution antenna beams. In addition to these developments, this issue features papers on several new single aperture telescopes. We also have three papers covering advances in technologies that are applicable to multiple projects, namely, antenna metrology, imaging techniques, and the use of phased array techniques. The issue begins with a short paper by the guest editors on "Radio Astronomy in the Early Twenty-First Century." There we attempt to put the topics of the following papers in historical perspective and to provide background information for readers whose expertise lies outside astronomy. The remaining papers are organized into three broad categories: single antenna telescopes, synthesis array telescopes, and the Square Kilometre Array (SKA). Although the last is also a synthesis array, the intensity of SKA-related work now under way around the world justifies a separate set of papers devoted to it. This issue features new single-aperture and synthesis array radio telescopes and covers advances in antenna metrology, imaging techniques, and the use of phased array technology.

Baars, Jacob W. M.; D'Addario, Larry R.; Thompson, A. Richard

2009-08-01

419

Remote Radio Sounding Science for JIMO  

NASA Technical Reports Server (NTRS)

Radio sounding of the Earth's top side 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 subsurface conductivities, of Europa, Ganymede, and Callisto. Spatial structures of ionospheric plasma above the moon surfaces vary in response to magnetic field perturbations from (1) magnetospheric plasma flows, (2) ionospheric currents from ionization of sputtered surface material, and (3) induced electric currents in salty subsurface oceans. Radio sounding at 3 kHz to 10 MHz can provide globally-determined electron densities necessary for the extraction of the oceanic current signals and supplements in-situ plasma and magnetic field measurements. Subsurface variations in conductivity, can be investigated by radio sounding from 10 MHz to 40 MHz allowing the determination of the presence of dense and solid-liquid phase boundaries associated with oceans and related structures in overlying ice crusts.

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

2003-01-01

420

The Solar Imaging Radio Array (SIRA) Mission  

NASA Astrophysics Data System (ADS)

The Solar Imaging Radio Array will be proposed to NASA as a Medium Explorer (MIDEX) mission by a team of investigators at GSFC, JPL, NRL, MIT, and UC Berkeley. The main science goal of the mission is imaging and tracking of solar radio bursts, particularly those associated with coronal mass ejections, and understanding their evolution and influence on Earth's magnetosphere. Related goals are mapping the 3-dimensional morphology of the interplanetary magnetic field and improving the prediction of geomagnetic storms. A number of topics in galactic and extragalactic astrophysics will also be addressed by SIRA. The mission concept is a free-flying array of about 16 small, inexpensive satellites forming an aperture synthesis interferometer in space. By observing from above the ionosphere, and far from terrestrial radio interference, SIRA will cover frequencies between a few tens of kHz up to 15 MHz. This wide spectral window is essentially unexplored with high angular resolution. Part of this work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Jones, D. L.; MacDowall, R.; Gopalswamy, N.; Kaiser, M.; Reiner, M.; Demaio, L.; Weiler, K.; Kasper, J.; Bale, S.; Howard, R.

2004-12-01

421

Digital-to-radio converter for software radio  

Microsoft Academic Search

We have proposed a digital-to-radio (D\\/R) converter that can directly change a digital signal generated by a logic circuit into a radio signal. This D\\/R converter enables an RF circuit and an antenna to be composed of one simple device, and the radio can be directly controlled by software; this is the essence of software radio. The proposed converter is

Takeharu Kohri; Takeshi Hattori

2000-01-01

422

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.

423

Radio Emission from Supernovae  

SciTech Connect

Study of radio supernovae over the past 27 years includes more than three dozen detected objects and more than 150 upper limits. From this work it is possible to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. It is also possible to detect ionized hydrogen along the line of sight, to demonstrate binary properties of the presupernova stellar system, and to detect dumpiness of the circumstellar material.

Weiler, Kurt W. [Naval Research Laboratory, Code 7210, Washington, DC 20375-5351 (United States); Panagia, Nino [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Supernova Ltd., Olde Yard Village 131, Northsound Road, Virgin Gorda, British Virgin Islands (United States); Sramek, Richard A. [INAF/Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); PO Box 0, National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Van Dyk, Schuyler D. [IPAC/Caltech, Mail Code 100-22, Pasadena, CA 91125 (United States); Williams, Christopher L. [Naval Research Laboratory, Code 7210, Washington, DC 20375-5351 (United States); Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Stockdale, Christopher J.; Kelley, Matthew T. [Marquette University, Physics Department, P.O. Box 1881, Milwaukee, WI 53214-1881 (United States)

2009-05-03

424

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

425

NASARC - NUMERICAL ARC SEGMENTATION ALGORITHM FOR A RADIO CONFERENCE  

NASA Technical Reports Server (NTRS)

NASARC was developed from the general planning principles and decisions of both sessions of the World Administrative Radio Conference on the Use of the Geostationary Satellite Orbit and on the Planning of Space Services Utilizing It (WARC-85, WARC-88). NASARC was written to help countries satisfy requirements for nation-wide Fixed Satellite services from at least one orbital position within a predetermined arc. The NASARC-generated predetermined arcs are each based on a common arc segment visible to a group of compatible service areas, and provide a means of generating a highly flexible allotment plan with a reduced need for coordination among administrations. The selection of particular groupings of service areas and their associated predetermined arcs is made according to a heuristic approach using several figures of merit designed to confront the most difficult allotment problems. NASARC attempts to select groupings and predetermined arc sizes so that the requirements of all administrations are met before the available orbital arc is exhausted. The predetermined arcs allow considerable freedom of choice in the positioning of space stations for all members of any grouping. The approach to allotment planning for which NASARC was designed consists of two phases. The first is the use of NASARC to identify predetermined arc segments common to groups of administrations. Those administrations within a group and sharing a common predetermined arc segment would be able to position their individual space stations at any one of a number of orbital positions within the predetermined arc. The second phase involves the use of a plan synthesis program (such as the ORBIT program resident at the International Frequency Registration Board in Geneva, Switzerland) to identify example scenarios of specific space station placements. NASARC software is modular, and consists of several programs to be run in sequence. The grouping module, NASARC1, identifies compatible groups of several service areas that are sufficiently separated geographically so that co-location or near co-location of their space stations will permit a user-specified downlink performance criterion to be satisfied. Pairwise compatibility between systems is assessed on the basis of the satellite separation required to meet this criterion. NASARC2 examines all groups of compatible administrations with their corresponding arc segments and computes a common predetermined arc. After an orbital slot of sufficient size has been found, NASARC2 calculates the required orbital separation between the critical group and its potential east and west neighbors and determines predetermined arc placement accordingly. NASARC3 updates and extends the feasible orbital locations for predetermined arcs associated with compatible groups of service areas to provide flexibility for rearrangement if necessary. NASARC4 performs rearrangement of predetermined arc segments where rearrangement will provide increased total arc available for subsequent placement of additional predetermined arcs and produces the final output report of the NASARC package. In addition to planning assumed homogeneous systems, NASARC can take into account such factors as rain attenuation, individual antenna parameters, power calculation options, minimum power values, different required carrier-to-interface ratios, variable grouping criteria, and affiliated sets of service areas. The modules allow the baseline assumptions to be modified, some on an individual service area basis. NASARC array dimensions have been structured to fit within the currently available 12MB memory capacity of the International Frequency Registration Board computer facility. NASARC was written in ANSI standard FORTRAN 77 and developed on an AMDAHL 5860 running under the IBM VM operating system. The package requires 8.1MB of central memory. NASARC (version 4.0) was written in 1988. IBM and VM are registered trademarks of International Business Machines. AMDAHL 5860 is a trademark of Amdahl Corporation.

Whyte, W. A.

1994-01-01

426

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

Federal Register 2010, 2011, 2012, 2013

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

2011-06-15

427

Establishment of Alternative Corporations by Selected Legal Services Corporation Grant Recipients.  

National Technical Information Service (NTIS)

GAO reviewed corporations established by three Legal Services Corporation (LSC) grant recipients allegedly to avoid grant restrictions. In reviewing these 'alternative' corporations, GAO found that: The LSC Act and regulations do not prohibit LSC grant re...

1985-01-01

428

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

Federal Register 2010, 2011, 2012, 2013

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

2010-04-19

429

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

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

2014-01-01

430

Algorithmic Advances for Software Radios.  

National Technical Information Service (NTIS)

Software radios replace most communication hardware with software. Software radios require new algorithms. Demodulation is the bottleneck in a software 802.11b implementation. Standard maximum-likelihood demodulator based on the fast Walsh-Hadamard transf...

M. Frigo

2003-01-01

431

The Black Hole Mass and Radio Characteristics of Radio Quasars  

NASA Astrophysics Data System (ADS)

In this paper, we collect the redshift, bolometric luminosity, full-width at half maximum (FWHM), monochromatic luminosity at 5100&:Aring;, radio loudness of 117 quasars, including 20 radio quiet quasars and 97 radio loud quasars. Then we calculate the black hole mass and Eddington ratio with the reverberation mapping method, and calculate the radio luminosity using total 5 GHz flux density. By analyzing the relations among them, our conclusions are as follows: (1) there are weak correlations between black hole mass and bolometric luminosity, between black hole mass and radio loudness, and between black hole mass and radio luminosity for radio quiet quasars (RQQs), while there are strong correlations between black hole mass and bolometric luminosity, between black hole mass and radio loudness, and between black hole mass and radio luminosity for radio loud quasars (RLQs); (2) there are weak correlations between bolometric luminosity and radio luminosity, and between bolometric luminosity and monochromatic luminosity at 5100Å for RQQs, while there are strong correlations between bolometric luminosity and radio luminosity, and between bolometric luminosity and monochromatic luminosity at 5100Å for RLQs; (3) the distributions of black hole mass, FWHM and Eddington ratio between RQQs and RLQs are different. From these results we suggest that the difference in black hole mass between RQQs and RLQs is predominantly due to the difference in FWHM between RQQs and RLQs; the difference between RQQs and RLQs is not due to the difference in orientation, but due to the difference in intrinsic property; the black hole mass, spin of black hole, Eddington ratio and morphology of host galaxy play an important role in explaining the origin of radio loudness and the radio loudness "bimodality"; there is a close link between the disk accretion rate and the generation of the relativistic radio jet.

Xiong, D. R.; Zhang, X.; Zheng, Y. G.; Huang, B. R.; Mao, L. S.; Liu, W. G.

2012-09-01

432

Correlation between X-Ray Light-Curve Shape and Radio Arrival Time in the Vela Pulsar  

NASA Astrophysics Data System (ADS)

We report the results of simultaneous observations of the Vela pulsar in X-rays and radio from the RXTE satellite and the Mount Pleasant Radio Observatory in Tasmania. We sought correlations between Vela's X-ray emission and radio arrival times on a pulse-by-pulse basis. At a confidence level of 99.8% we have found significantly higher flux density in Vela's main X-ray peak during radio pulses that arrived early. This excess flux shifts to the ``trough'' following the second X-ray peak during radio pulses that arrive later. Our results suggest that the mechanism producing the radio pulses is intimately connected to the mechanism producing X-rays. Current models using resonant absorption of radio emission in the outer magnetosphere as a cause of the X-ray emission are explored as a possible explanation for the correlation.

Lommen, A.; Donovan, J.; Gwinn, C.; Arzoumanian, Z.; Harding, A.; Strickman, M.; Dodson, R.; McCulloch, P.; Moffett, D.

2007-03-01

433

Radio frequency identification (RFID)  

Microsoft Academic Search

First conceived in 1948, Radio Frequency Identification (RFID) has taken many years for the technology to mature to the point where it is sufficiently affordable and reliable for widespread use. From Electronic Article Surveillance (EAS) for article (mainly clothing) security to more sophisticated uses, RFID is seen by some as the inevitable replacement for bar codes. With increasing use comes

C. M. Roberts

2006-01-01

434

#EdChat Radio  

NSDL National Science Digital Library

This iTunes radio channel is available for free download by discussion or the entire database by subscription. Each podcast reflects on the Twitter #EdChat conversation of the week on a range of educational topics. Some topics of particular interest to math coaches are Mentoring New Teachers and Reinventing the Classroom.

Network, Bam R.

2013-01-01

435

Today'S Radio Electronics.  

National Technical Information Service (NTIS)

The directives of the 23rd Congress of the CPSU regarding the Five-Year-Plan for the Development of the National Economy of the USSR for the 1966-1970 period call for accelerating growth rates in a number of production sectors, including that of radio and...

1970-01-01

436

Radio Wall Street  

NSDL National Science Digital Library

Radio Wall Street, brought to you by Investor Broadcast Network, offers current financial news for investors. RealAudio files are organized in sections including top stories, technology news, IPOs, and mutual funds. Special sections provide interviews with leading CEOs and investment analysts. Daily features and popular programs are listed at the bottom of the site.

437

World Wide Radio  

NSDL National Science Digital Library

The World Wide Radio (WWR) is the best way for people to stay in touch with some of the hottest new bands from throughout the world. Audio clips and biographies are available for most of the bands listed. Also, you can order CDs or cassettes for most of the bands listed. http://www.bigplanet.com/wwr.html

438

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

439

Cassini Radio Science  

Microsoft Academic Search

Cassini radio science investigations will be conducted both during the cruise (gravitational wave and conjunction experiments) and the Saturnian tour of the mission (atmospheric and ionospheric occultations, ring occultations, determinations of masses and gravity fields). New technologies in the construction of the instrument, which consists of a portion on-board the spacecraft and another portion on the ground, including the use

A. J. Kliore; J. D. Anderson; J. W. Armstrong; S. W. Asmar; C. L. Hamilton; N. J. Rappaport; H. D. Wahlquist; R. Ambrosini; F. M. Flasar; R. G. French; L. Iess; E. A. Marouf; A. F. Nagy

2004-01-01

440

Cassini Radio Science  

Microsoft Academic Search

Cassini radio science investigations will be conducted both during the cruise (gravitational wave and conjunction experiments) and the Saturnian tour of the mission (atmospheric and ionospheric occultations, ring occultations, determinations of masses and gravity fields). New technologies in the construction of the instrument, which consists of a portion on-board the spacecraft and another portion on the ground, including the use

A. J. KLIORE; J. D. ANDERSON; J. W. ARMSTRONG; S. W. ASMAR; C. L. HAMILTON; N. J. RAPPAPORT; H. D. WAHLQUIST; R. Ambrosini; F. M. FLASAR; R. G. FRENCH; L. Iess; E. A. MAROUF; A. F. NAGY

441

Extremely red radio galaxies  

Microsoft Academic Search

At least half the radio galaxies at z > 1 in the 7C Redshift Survey have extremely red colours (R-K > 5), consistent with stellar populations which formed at high redshift (z >~eq 5). We discuss the implications of this for the evolution of massive galaxies in general and for the fraction of near-IR-selected EROs which host AGN, a result

C. J. Willott; S. Rawlings; K. M. Blundell

2001-01-01

442

Mullard Radio Astronomy Observatory  

NASA Astrophysics Data System (ADS)

The Mullard Radio Astronomy Observatory (MRAO) is operated by the Astrophysics Group of the Department of Physics at the Cavendish Laboratory. The observatory is located 8 km south-west of Cambridge at Lord's Bridge and was established in 1957 through the generosity of Mullard Limited with support from the Science Research Council. Current work is supported by the PARTICLE PHYSICS AND ASTRONOMY R...

Murdin, P.

2000-11-01

443

Common Submarine Radio Room.  

National Technical Information Service (NTIS)

The CSRR program represents a paradigm shift in the way radio room equipment is procured in the submarine fleet. This program is managed under PEO C4I by SPAWAR PMW 770. This thesis examines the cost, schedule, and performance parameters of the CSRR progr...

S. S. Roderick

2011-01-01

444

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

445

Community Control of Local Radio.  

ERIC Educational Resources Information Center

This study was designed to determine to what extent local communities control the local radio which serves them, by what formal mechanisms their control is secured, and the underlying assumptions and goals which govern the practice of the professionals who have charge of the facilities. Two British radio stations, BBC Radio Bristol and the…

Lewis, Peter M.

446

ROSAT Results for Radio Galaxies  

NASA Technical Reports Server (NTRS)

Simple conclusions concerning the origin of X-ray emission in radio galaxies from pre-ROSAT correlations (e.g., X-ray versus core-radio luminosity) are not to be trusted. Radio galaxies are complex and diverse X-ray emitters. Current answers to key questions are presented.

Worrall, Diana M.; Birkinshaw, M.

1996-01-01

447

The Nicaragua Radio Mathematics Project.  

ERIC Educational Resources Information Center

The Radio Mathematics Project was funded by the Agency for International Development to design, implement, and evaluate, in conjunction with personnel of a developing country, a system for teaching primary-grade mathematics by radio. In July 1974, a project in Nicaragua began with a series of radio presentations, each followed by 20 minutes of…

Searle, Barbara

448

Concept-Level Analytical Procedures for Loading Nonprocessing Communication Satellites with Direct-Sequence, Spread-Spectrum Signals.  

National Technical Information Service (NTIS)

This report is the second in a series devoted to presenting the analytical procedures and mathematical formulations required to construct a computer model of a military communication satellite system, load it efficiently with the radio signals required to...

E. Bedrosian G. Huth

1996-01-01

449

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

450

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

451

What are Satellites?  

NSDL National Science Digital Library

In this activity, students differentiate between natural satellites and artificial satellites, and are challenged to create a model of an artificial satellite, including calculating the amount of energy required to power the satellite and the size of the solar array required to generate that power. Student worksheets, answer sheet, illustrations of satellites, teacher tips and Web links are included. This is Lesson 2 in What are Satellites, part of IMAGERS, Interactive Media Adventures for Grade School Education using Remote Sensing. The website provides hands-on activities in the classroom supporting the science content in two interactive media books, The Adventures of Echo the Bat and Amelia the Pigeon.

452

Remote Radio Sounding Science For JIMO  

NASA Astrophysics Data System (ADS)

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 subsurface structures of Europa, Ganymede, and Callisto. Spatial structures of ionospheric plasma above the surfaces of these bodies will vary in response to magnetic field perturbations from magnetospheric plasma flows, ionospheric currents from ionization of sputtered surface material, and induced electric currents in salty subsurface oceans. Radio sounding at 3 kHz to 10 MHz will provide globally-determined electron densities necessary for the extraction of the oceanic current signals and will supplement in-situ plasma and magnetic field measurements. Long-range magnetospheric sounding, pioneered by the radio plasma imager (RPI) instrument on IMAGE, has provided electron density distributions along magnetic field lines and in radial directions on time scales of minutes. RPI has also been able to measure the entire electron plasma density distributions (in the orbit plane) of the Earth's polar cap and the plasmasphere within one pass of the spacecraft. In a similar manner, a radio sounder orbiting an icy moon would be able to measure the electron density along the magnetic field into each hemisphere and provide information on the Jovian magnetospheric background, the magnetospheric influences on the moon's ionospheres, and distortions of magnetic field line geometry from model predictions. The higher-power source available from JIMO would allow radio sounding transmissions at much higher powers than those used on ISIS or IMAGE making subsurface sounding of the Jovian icy moons possible at frequencies above the ionosphere peak plasma frequency from~5 MHz to 40 MHz. Subsurface variations in dielectric properties, can be investigated by radio sounding allowing the detection of dense and solid-liquid phase boundaries associated with oceans and related structures in overlying ice crusts.

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

2003-12-01

453

International Ultraviolet Explorer (IUE) satellite mission analysis  

NASA Technical Reports Server (NTRS)

The results are presented of the mission analysis performed by Computer Sciences Corporation (CSC) in support of the International Ultraviolet Explorer (IUE) satellite. The launch window is open for three separate periods (for a total time of 7 months) during the year extending from July 20, 1977, to July 20, 1978. The synchronous orbit shadow constraint limits the launch window to approximately 88 minutes per day. Apogee boost motor fuel was computed to be 455 pounds (206 kilograms) and on-station weight was 931 pounds (422 kilograms). The target orbit is elliptical synchronous, with eccentricity 0.272 and 24 hour period.

Cook, R. A.; Griffin, J. H.

1975-01-01

454

Radio search for gamma-ray pulsar counterparts  

Microsoft Academic Search

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

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

2009-01-01

455

Satellite diversity in mobile satellite CDMA systems  

Microsoft Academic Search

The paper addresses the exploitation of satellite diversity in a satellite mobile network. In particular, we focus on the impact of diversity on service availability and on system capacity, considering the forward link of a CDMA system with a multisatellite and multibeam architecture. The analysis includes the effects of path blockage, intrabeam and interbeam interference, imperfect power control, and fading

Carlo Caini; Giovanni Emanuele Corazza

2001-01-01

456

Potential markets for advanced satellite communications  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

457

Measurement of a large deployable antenna for radio astronomy in space  

Microsoft Academic Search

A large radio astronomy antenna on Halca satellite was deployed in 1997 in space. The main reflector with the maximum diameter of 10 m is composed in a novel deployment scheme of tension truss as shown. The operating frequencies are 1.66 GHz (L-band), 4.85 GHz (C-band) and 22.15 GHz (Ka-band), all protected for radio astronomy use. If a mast is

T. Takano; S. Kuroda; H. Kobayashi; N. Kawaguch; E. Hanayama

2001-01-01

458

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

459

ROSAT results for radio galaxies  

NASA Technical Reports Server (NTRS)

Previous, pre-Rosat conclusions concerning the origin of X-ray emission in radio galaxies derived from correlations of X-ray versus core radio luminosity are considered to be unreliable. In relation to this, the following questions that are intended to be solved by Rosat observations are discussed: are the X-rays nuclear, thermal or a combination; what constraints are placed on relativistic beaming models which unify BL Lac objects and Fanaroff and Riley type radio galaxies through orientation; is there sufficient external pressure to give static support to the radio jets and lobes, and if hot gaseous atmospheres are seen, are they shaped by the radio jets?

Worrall, D. M.; Birkinshaw, M.

1996-01-01

460

25 CFR 226.8 - Corporation and corporate information.  

Code of Federal Regulations, 2011 CFR

...evidence of authority of its officers to execute papers; and with its first application it shall also file a certified copy of its Articles of Incorporation and, if foreign to the State of Oklahoma, evidence showing compliance with the corporation laws...

2011-04-01

461

Which satellites were used?  

The three satellites ERBS, NOAA-9, NOAA-10 carrying two ERBE instrument packages (Scanner ... and Atmospheric Administration (NOAA) weather monitoring satellites, NOAA-9 and NOAA-10 in 1984 and 1986, respectively. ...

2012-07-19

462

Olympus Satellite Program.  

National Technical Information Service (NTIS)

The history of the Olympus program is described. The factors taken into consideration in designing the satellite and the reasons for building the satellite are described. A program timeline is included.

J. Paul

1989-01-01

463

Satellite Maneuver Evaluation Tool.  

National Technical Information Service (NTIS)

When first introduced to orbital mechanics, students often experience difficulty in visualizing a satellite's actual path through space. The Satellite Maneuver Evaluation Tool (SMET) seeks to alleviate that problem. SMET is a three-dimensional color graph...

C. I. Noriega

1990-01-01

464

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

465

Are Satellites for People?  

ERIC Educational Resources Information Center

The author identifies some of the jobs which satellites can do for education," looks at the constraints which limit satellite use" and trys to raise the questions for education which they present." (Author/AK)

Perraton, H. D.

1971-01-01

466

Mobile satellite communications in the Forest Service  

NASA Astrophysics Data System (ADS)

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

Warren, John R.

1988-05-01

467

Operating frequencies for educational satellite services  

NASA Technical Reports Server (NTRS)

The factors affecting the choice of transmission frequencies are identified. These include international radio regulations, natural environment, man-made environment, hardware considerations, and interconnection and spectrum space considerations. An analysis is presented of international radio regulations with emphasis on 1963 EARC and 1971 WARC frequency allocations, powerflux density restrictions, and resolutions concerning introduction of broadcasting-satellite systems. Natural-environmental effects were divided into two categories: (1) those due to transionospheric propagation, and (2) those that can be credited to the earth's atmosphere and its constituents. The frequency dependence of the signal attenuation, signal distortion, and contributions to system noise temperature due to environmental effects are discussed, and comparisons were made for frequencies of interest. Man-made environmental effects were examined in terms of various sharing limitations as well as the indigenous noise contribution to the overall system noise.

Singh, J. P.

1971-01-01

468

Mobile satellite communications in the Forest Service  

NASA Technical Reports Server (NTRS)

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

Warren, John R.

1988-01-01

469

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

470

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.

471

Optical data communication for Earth observation satellite systems  

NASA Astrophysics Data System (ADS)

The current development status of optical communication engineering in comparison to the conventional microwave systems and the different configurations of the optical data communication for Earth observation satellite systems are described. An outlook to future optical communication satellite systems is given. During the last decade Earth observation became more and more important for the extension of the knowledge about our planet and the human influence on nature. Today pictures taken by satellites are used, for example, to discover mineral resources or to predict harvest, crops, climate, and environment variations and their influence on the population. A new and up to date application for Earth observation satellites can be the verification of disarmament arrangements and the control of crises areas. To solve these tasks a system of Earth observing satellites with sensors tailored to the envisaged mission is necessary. Besides these low Earth orbiting satellites, a global Earth observation system consists of at least two data relay satellites. The communication between the satellites will be established via Inter-Satellite Links (ISL) and Inter-Orbit Links (IOL). On these links, bitrates up to 1 Gbit/s must be taken into account. Due to the increasing scarcity of suitable frequencies, higher carrier frequencies must probably be considered, and possible interference with terrestrial radio relay systems are two main problems for a realization in microwave technique. One important step to tackle these problems is the use of optical frequencies for IOL's and ISL's.

Fischer, J.; Loecherbach, E.

1991-10-01

472

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

473

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.

474

IMAGE Satellite Scale Model  

NSDL National Science Digital Library

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

475

Satellite horn antennas design  

Microsoft Academic Search

Telecommunication satellite horn antennas require now-a-days more and more stringent requirements based mainly in the increased bandwidth necessary to accommodate more transponders to increase the capacity of the new satellite services. In this aspect horn antennas play a key role in the development of wider bandwidth services on board satellites because they are usually the reason that limits bandwidth in

Jorge Teniente; Ramón Gonzalo; Carlos del Río

2009-01-01

476

A satellite for Asia  

Microsoft Academic Search

In April 1990, an American satellite will be launched by China on the Long March 3 rocket. This satellite, called AsiaSat 1 will provide domestic telecommunications service to the countries of Asia. AsiaSat 1 is designed to provide satellite communications services to China, Thailand and Pakistan. These services will also be available for the use of neighboring countries such as

John D. R. Lawrence

1989-01-01

477

Save Money with a Corporate Style Guide.  

ERIC Educational Resources Information Center

Argues that corporate style guides create consistency in documents, promote a professional image, train new employees, and define document generation. Describes how to develop a corporate style guide. (SR)

Allen, Paul R.

1995-01-01

478

Beyond Compliance: Integrating Nonproliferation into Corporate Sustainability  

SciTech Connect

This paper investigates nonproliferation as a potential corporate sustainability value. It reviews the history of corporate sustainability, builds the case for nonproliferation as a sustainability value, and develops recommendations for the integration of nonproliferation into the frameworks of sustainability.

Hund, Gretchen; Kurzrok, Andrew J.

2013-06-01

479

Corporate Civil Disobedience in the Consumer Interest.  

ERIC Educational Resources Information Center

Through catalytic issue management, corporations proactively seek to affect resolutions of issues in which they have some interest. Corporations now catalyze legal changes by purposely disobeying existing law, facing the associated consequences, and lobbying for desired changes. (Author)

Dennis, Michael R.; And Others

1994-01-01

480

78 FR 29366 - Green Mountain Power Corporation  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF ENERGY Federal Energy Regulatory Commission...TS04-277-002] Green Mountain Power Corporation...that on May 2, 2013, Green Mountain Power Corporation...intervention to the Federal Energy Regulatory...

2013-05-20

481

43 CFR 3902.25 - Corporations.  

Code of Federal Regulations, 2013 CFR

...to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL SHALE MANAGEMENT-GENERAL Qualification Requirements § 3902.25 Corporations. Corporate officers or...

2013-10-01

482

25 CFR 214.3 - Corporate information.  

Code of Federal Regulations, 2011 CFR

...BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.3 Corporate information. A corporation shall file with its first lease a...

2011-04-01

483

Advertising Strategies: Corporate and Product-Specific.  

National Technical Information Service (NTIS)

Presents a discussion of the corporate and product-specific advertising, strategies used in civilian industry. Variables affecting corporations' ad campaigns, e.g., media selection, are discussed. Report summarizes lessons learned form civilian advertisin...

R. F. Koenig

1984-01-01

484

Is Corporate Governance Ineffective in Emerging Markets.  

National Technical Information Service (NTIS)

The writer tests whether corporate governance is ineffective in emerging markets by estimating the link between CEO turnover and firm performance for over 1,200 firms in eight emerging markets. While previous papers on corporate governance in emerging mar...

M. S. Gibson

1999-01-01

485

Ten Principles of Corporate Real Estate Management  

Microsoft Academic Search

Offers a distillation of the central principles of corporate real estate management into ten concise points covering – inter alia – matching business and property strategies, monitoring property performance and integrating the physical, financial and organizational aspects of corporate real estate management.

Ranko Bon

1994-01-01

486

Pacifica Radio Archives  

NSDL National Science Digital Library

The Internet Archive has partnered with the Pacific Radio Archives to bring together this collection of over 460 audio files that chronicle "the political, cultural and artistic movements of the second half of the 20th century." The items here include documentaries, performances, discussions, debates, drama, poetry readings, commentaries, and radio arts. First-time visitors can start by look over the Most Downloaded Items Last Week area, which has included offerings such as "Say it LOUD: New Songs for Peace." One rather arresting item here is an interview with noted journalist Seymour Hersh about the My Lai incident. Also, visitors can browse the collection by subject or keyword, like Gore Vidal, Politics, or Allen Ginsberg.

487

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

488

Rosetta Radio Science Investigations  

NASA Technical Reports Server (NTRS)

The Rosetta Radio Science Investigations (RSI) experiment was selected by the European Space Agency to be included in the International Rosetta Mission to comet P/Wirtanen (launch in 2003, arrival and operational phase at the comet 2011-2013). The RSI science objectives address fundamental aspects of cometary physics such as the mass and bulk density of the nucleus, the gravity field, non-gravitational forces, the size and shape, the internal structure, the composition and roughness of the nucleus surface, the abundance of large dust grains and the plasma content in the coma and the combined dust and gas mass flux on the orbiter. RSI will make use of the radio system of the Rosetta spacecraft.

Patzold, M.; Neubauer, F. M.; Wennmacher, A.; Aksnes, K.; Anderson, J. D.; Asmar, S. W.; Tinto, M.; Tsurutani, B. T.; Yeomans, D. K.; Barriot, J. -P.; Bird, M. K.; Boehnhardt, H.; Gill, E.; Montenbruck, O.; Grun, E.; Hausler, B.; Ip, W. H.; Thomas, N.; Marouf, E. A.; Rickman, H.; Wallis, M. K.; Wickramasinghe, N. C.

1996-01-01

489

City Schools with Corporate Partners.  

ERIC Educational Resources Information Center

Discusses the District of Columbia's new career programs in its high schools, each in fields with projected job growth and each with corporate sponsors who participated in the program's design and curriculum development. Examines program costs, program development, design, and effectiveness. (CT)

McKenzie, Floretta Dukes

1985-01-01

490

The concept of corporate responsibility  

Microsoft Academic Search

Opening with Ford Motor Company as a case in point, this essay develops a broad and systematic approach to the field of business ethics. After an analysis of the form and content of the concept of responsibility, the author introduces the ‘principle of moral projection’ as a device for relating ethics to corporate policy. Pitfalls and objections to this strategy

Kenneth E. Goodpaster

1983-01-01