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1

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.

Satellite Imaging Corporation

2

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

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.

Monique Romeijn

4

The Aerospace Corporation 2009 Communication Satellite Systems  

E-print Network

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

Low, Steven H.

5

Corporate strategies for satellite communications  

NASA Astrophysics Data System (ADS)

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

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

1991-10-01

6

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.

7

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

8

Satellite Radio: Its Global Impact  

E-print Network

them as little as a cow appreciates the botanic marvels in the plants she munches." - Albert Einstein; Sirius uses 3 HEO (Tundra orbit) satellites XM started Sep 2001 and has >5 million subscribers Sirius

Udgaonkar, Jayant B.

9

Direct broadcast satellite-radio, receiver development  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

10

Simple rain attenuation prediction method for satellite radio links  

Microsoft Academic Search

The desirable features of a rain attenuation prediction method to be used in satellite radio link engineering are established, and a method satisfying such features is proposed. The method is tested over 77 satellite links situated in Europe, the U.S., Japan, and Australia. Comparisons are made with the International Radio Consultative Committee (CCIR) method. Using the worldwide coefficients for the

J. A. Garcia-Lopez; J. M. Hernando; J. M. Selga

1988-01-01

11

A Digital Satellite Communications System for Corporate Telecommunications  

Microsoft Academic Search

A satellite communications system has been implemented by Citicorp to meet its present and future internal domestic telecommunications requirements. This system is currently being used for voice and data transmission and video teleconferencing between corporate facilities in New York, Los Angeles, San Francisco, and Sioux Falls, SD. Six additional cities will be served by the end of 1984. This system

KENNETH A. MILLER; ARNOLD SCHOEN

1984-01-01

12

Radio occultation based on BeiDou satellite navigation  

NASA Astrophysics Data System (ADS)

With the development of GNSS systems, it has become a tendency that radio occultation is used to sense the Earth's atmosphere. By this means, the moisture, temperature, pressure, and total electron content can be derived. Based on the sensing results, more complicated models for atmosphere might come into being. Meteorology well benefits from this technology. As scheduled, the BD satellite navigation system will have a worldwide coverage by the end of 2020. Radio occultation studies in China have been highlighted in the recent decade. More and more feasibilities reports have been published in either domestic or international journals. Herein, some scenarios are proposed to assess the coverage of radio occultation based on two different phases of BD satellite navigation system. Phase one for BD is composed of GEO,IGSO and several MEO satellites. Phase two for BD consists mostly of 24 MEO satellites, some GEO and IGSO satellites. The characteristics of radio occultation based on these two phases are presented respectively.

Jiang, Hu; Hu, Haiying; Shen, Xue-min; Gong, Wenbin; Zhang, Yonghe

2014-11-01

13

Direct broadcast satellite service by direct broadcast satellite corporation  

NASA Astrophysics Data System (ADS)

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

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

1984-03-01

14

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

15

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

16

Satellite emission radio interferometric earth surveying series - GPS geodetic system  

NASA Technical Reports Server (NTRS)

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

Macdoran, P. F.

1979-01-01

17

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

Federal Register 2010, 2011, 2012, 2013, 2014

...satellite digital audio radio services for...performance of sound recordings and the making of...transmission of sound recordings and the making of ephemeral recordings in furtherance of...satellite digital audio radio...

2011-01-05

18

Improved Radio Emissivities for Satellites of Saturn  

NASA Astrophysics Data System (ADS)

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

Ries, Paul

2010-10-01

19

Fade durations in satellite-path mobile radio propagation  

NASA Astrophysics Data System (ADS)

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

Schmier, Robert G.; Bostian, Charles W.

1986-12-01

20

Fade durations in satellite-path mobile radio propagation  

NASA Technical Reports Server (NTRS)

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

Schmier, Robert G.; Bostian, Charles W.

1986-01-01

21

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

22

Towards generic satellite payloads : software radio , M.-L.Boucheret2  

E-print Network

and a foreseen solution is the software defined radio technology. In this paper we describe a way of introducing-user. In this context, the software defined radio as emerged. This concept covers a lot of techniques: hardware at the satellite level for regenerative systems. The software defined radio concept for satellite applications can

Mailhes, Corinne

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

Wireless trunked access through cellular radio and satellite systems for rural communications  

Microsoft Academic Search

The paper describes some access methods for rural telecommunication using radio links as trunk lines. A comparison is made between different radio techniques including cellular radio and satellite. A design is described for a village network connected to the outside world through fixed cellular radio links. Some economical and technical aspects are analyzed

R. Westerveld

1994-01-01

25

ATS6-satellite radio beacon measurements at Ootacamund, India  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

26

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

Code of Federal Regulations, 2012 CFR

...Licensing provisions for the 2.3 GHz satellite digital audio radio service...144 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses...

2012-10-01

27

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

Code of Federal Regulations, 2012 CFR

...214 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards 25...requirements for space stations in the satellite digital audio radio service...

2012-10-01

28

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

Code of Federal Regulations, 2011 CFR

...Licensing provisions for the 2.3 GHz satellite digital audio radio service...144 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses...

2011-10-01

29

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

Code of Federal Regulations, 2011 CFR

...214 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards 25...requirements for space stations in the satellite digital audio radio service...

2011-10-01

30

47 CFR 25.214 - Technical requirements for space stations in the Satellite Digital Audio Radio Service and...  

Code of Federal Regulations, 2013 CFR

...214 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards 25...requirements for space stations in the Satellite Digital Audio Radio Service...

2013-10-01

31

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

Code of Federal Regulations, 2014 CFR

...Licensing provisions for the 2.3 GHz satellite digital audio radio service...144 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses...

2014-10-01

32

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...144 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses...

2013-10-01

33

47 CFR 25.214 - Technical requirements for space stations in the Satellite Digital Audio Radio Service and...  

Code of Federal Regulations, 2014 CFR

...214 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards 25...requirements for space stations in the Satellite Digital Audio Radio Service...

2014-10-01

34

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

Code of Federal Regulations, 2010 CFR

...214 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards 25...requirements for space stations in the satellite digital audio radio service...

2010-10-01

35

Satellites of Radio AGN in SDSS: Insights into AGN Triggering and Feedback  

NASA Astrophysics Data System (ADS)

We study the effects of radio jets on galaxies in their vicinity (satellites) and the role of satellites in triggering radio-loud active galactic nuclei (AGNs). The study compares the aggregate properties of satellites of a sample of 7220 radio AGNs at z < 0.3 (identified by Best & Heckman from the SDSS and NVSS+FIRST surveys) to the satellites of a control sample of radio-quiet galaxies, which are matched in redshift, color, luminosity, and axis ratio, as well as by environment type: field galaxies, cluster members, and brightest cluster galaxies (BCGs). Remarkably, we find that radio AGNs exhibit on average a 50% excess (17? significance) in the number of satellites within 100 kpc even though the cluster membership was controlled (e.g., radio BCGs have more satellites than radio-quiet BCGs, etc.). Satellite excess is not confirmed for high-excitation sources, which are only 2% of radio AGN. Extra satellites may be responsible for raising the probability for hot gas AGN accretion via tidal effects or may otherwise enhance the intensity or duration of the radio-emitting phase. Furthermore, we find that the incidence of radio AGNs among potential hosts (massive ellipticals) is similar for field galaxies and for non-BCG cluster members, suggesting that AGN fueling depends primarily on conditions in the host halo rather than the parent, cluster halo. Regarding feedback, we find that radio AGNs, either high or low excitation, have no detectable effect on star formation in their satellites, as neither induced star formation nor star formation quenching is present in more than ~1% of radio AGN.

Pace, Cameron; Salim, Samir

2014-04-01

36

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

Federal Register 2010, 2011, 2012, 2013, 2014

...FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 25...Rules and Policies for the Satellite Digital Audio Radio Service...Frequency Band AGENCY: Federal Communications Commission. ACTION: Final...requirements contained in the Satellite Digital Audio Radio...

2011-09-19

37

Terrestrial Myriametric Radio Burst Observed by IMAGE and Geotail Satellites  

NASA Technical Reports Server (NTRS)

We report the simultaneous detection of a terrestrial myriametric radio burst (TMRB) by IMAGE and Geotail on 19 August 2001. The TMRB was confined in time (0830-1006 UT) and frequency (12-50kHz). Comparisons with all known nonthermal myriametric radiation components reveal that the TMRB might be a distinct radiation with a source that is unrelated to the previously known radiation. Considerations of beaming from spin-modulation analysis and observing satellite and source locations suggest that the TMRB may have a fan beamlike radiation pattern emitted by a discrete, dayside source located along the poleward edge of magnetospheric cusp field lines. TMRB responsiveness to IMF Bz and By orientations suggests that a possible source of the TMRB could be due to dayside magnetic reconnection instigated by northward interplanetary field condition.

Fung, Shing F.; Hashimoto, KoZo; Kojima, Hirotsugu; Boardson, Scott A.; Garcia, Leonard N.; Matsumoto, Hiroshi; Green, James L.; Reinisch, Bodo W.

2013-01-01

38

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Digital Audio Radio Satellite Service in the...AGENCY: Federal Communications Commission. ACTION...Operation of Wireless Communications Services in the...Digital Audio Radio Satellite Service in the...Operation of Wireless Communications Services in the...Digital Audio Radio Satellite Service in...

2013-07-23

39

Monitoring of Earthquake Disasters by Satellite Radio Tomography  

NASA Astrophysics Data System (ADS)

This work addresses lithospheric-ionospheric coupling during strong earthquakes (EQ). Particular interest is placed on the physical phenomena preceding EQs - the precursors. We discuss both the ionospheric implications of EQs, and the ionospheric precursors to EQ. The requisite ionospheric sounding is carried out using satellite navigational system data; the data are analyzed using the methods of satellite radio tomography (RT). Signals from both low-orbiting beacons (Transit, Tsikada, etc.) and high orbiting global navigational satellite systems (GNSS including GPS and GLONASS) are used. The resulting 2D and 3D tomographic images and their time flow (4D RT) make it possible to study the spatiotemporal structure of ionospheric perturbations induced by EQs and EQ precursors, and to distinguish ionospheric responses to processes of EQ preparation against the effects of other factors. Low-orbital RT (LORT) provides almost "instantaneous" (with a time span of 5-8 min) 2-D snapshots of the electron density over the seismically active region of interest. LORT allows 2D imaging of various anomalies, including wave structures such as ionospheric manifestations of acoustic-gravity waves (AGW), wave-like disturbances, and solitary waves with the gaps between images, depending on the number of operating satellites (currently, 30-100 minutes). High-orbital RT (HORT) is capable of imaging 4D distributions of ionospheric plasma (resulting in 3D snapshots every 20-30 minutes). Using this approach, one can reconstruct RT images of ionospheric irregularities, wave structures, and perturbations such as solitary waves. In regions with a sufficient number of GNSS receivers (California, Japan), 4-D RT images can be generated every 2-4 minutes. The spatial resolution of LORT and HORT systems is on the order of 20-40, and 100 km, respectively. The combination of LORT and HORT systems has the potential for exploiting data provided by other experimental techniques, including radio occultation, ionosonde, and radar measurements, inter alia. Further integration of RT systems with other multi-instrumental observations of EQ-related phenomena is possible. We present the results of long-term RT studies of the ionosphere over California, Alaska, and Southeast Asia (Taiwan region). We used the experimental data from the LORT systems in Alaska and Taiwan. At present, LORT system in California is put into operation. The input for HORT imaging was the data from IGS, UNAVCO, and Japan GPS network stations. A variety of examples are given to illustrate the ionospheric perturbations associated with EQs and to illustrate EQ-related, ionospheric precursors including specific ionospheric disturbances, AGW, and solitary-wave-like perturbations. Several dozen precursors are identified from the results of many years of RT studies in Alaska and the Taiwan region during the period from 2006-2008. We discuss the results of a HORT analysis of a series of recent EQs including San Simeon (2003), Parkfield (2004), Sumatra (2004), Sichuan (China, 2008), Haiti (2010), Chile (2010), Japan (Tohoku, 2011), and other events. We are grateful to Dr. L.-C.Tsai and Northwest Research Associates, Inc., for providing raw RT data for Taiwan and Alaska.

Kunitsyn, V.; Andreeva, E.; Nesterov, I.; Rekenthaler, D. A.

2011-12-01

40

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

41

Analysis of the Low-Frequency Radio Noise Environment at Satellite Heights from Terrestrial Sources  

Microsoft Academic Search

We have investigated the propagation of terrestrial radio sources from 1 to 30 MHz (HF spectral region) through the ionosphere for the purpose of characterizing the interference spectrum on potential space-based, low-frequency-radio telescopes. A recent survey of the HF noise environment at satellite heights from 1 to 14 MHz has been conducted using the WIND spacecraft. Radio frequencies for which

M. F. Taylor; J. P. Basart; M. McCoy; E. Rios

1996-01-01

42

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

43

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

44

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

45

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

Microsoft Academic Search

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

F. W. Perkins; R. G. Roble

1978-01-01

46

Workshop on Satellite Power Systems (SPS) effects on optical and radio astronomy  

SciTech Connect

The impacts of the SPS on astronomy were 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 causing the satellites to appear as individual stationary radio sources; finally, the fixed location of the geostationary satellite orbits would result in fixed regions of the sky being unusable for observations. (GHT)

Stokes, G.M.; Ekstrom, P.A. (eds.)

1980-04-01

47

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

48

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

Microsoft Academic Search

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

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

1998-01-01

49

Effects of the Earth's Ionosphere on HF Radio Astronomy from Artificial Satellites  

Microsoft Academic Search

A theoretical analysis of the effects of the ionosphere on HF observations from satellite-borne radio telescopes is presented. The primary effect investigated is the focusing effect of the ionosphere on incoming cosmic noise. This effect was computed according to the Hamiltonian equations for a ray path in a general magnetoionic medium, assuming the ionosphere to be a nonhomogenous, nonisotropic, magnetoionic

M. D. Grossi; K. M. Strom; S. E. Strom

1961-01-01

50

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

NASA Astrophysics Data System (ADS)

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

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

1989-11-01

51

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

52

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.; Belin, F.; Meijerink, A.; Monna, B.; Rotteveel, J.; Boer, M. A.; Bongers, E.; Boom, E.; van Tuijl, E.; van Staveren, A.

53

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

NASA Astrophysics Data System (ADS)

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

Savio Bradford, Brandon; Gutierrez Cabello, Jordi

54

Phase and pattern calibration of the Jicamarca Radio Observatory radar using satellites  

NASA Astrophysics Data System (ADS)

The Jicamarca Radio Observatory (JRO) main 50-MHz array antenna radar system with multiple receivers is being used to study meteors via two interferometric receiving modes. One of the major challenges in these studies is the phase calibration of the various receiver (interferometric) channels (legs). While investigating some ambiguous features in meteor head-echo results, we developed a `new' calibration technique that employs satellite observations to produce more accurate phase and pattern measurements than were previously available. This calibration technique, which resolves head-echo ambiguities, uses the fact that Earth-orbiting satellites are in gravitationally well-defined orbits and thus the pulse-to-pulse radar returns must be consistent (coherent) for an entire satellite pass through the radar beam. In particular, the satellite yields a reliable point source for phase and thus interferometry-derived range, Doppler and trajectory calibration. Using several satellites observed during standard meteor observations, we derive satellite orbital parameters by matching the observed and modelled three-dimensional trajectory and Doppler results. This approach uncovered subtle phase distortions that led to interferometry-derived trajectory distortions that are important only to point targets such as meteor head-echoes. We present the array calibration and radar imaging of satellite passes from our meteor observations of 2010 April 15/16. Future observations of a priori known satellites would likely yield significantly more accurate calibrations, especially of distant side lobes.

Gao, B.; Mathews, J. D.

2015-02-01

55

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

56

The Influence of The Galilean Satellites on Radio Emissions From The Jovian System  

NASA Technical Reports Server (NTRS)

The Galilean satellites influence radio emissions from the Jovian system in a variety of ways. The best and most familiar example of these is the Io control of decametric radiation discovered in 1964 by Bigg. Voyager observations of broadband kilometric radiation revealed a low-latitude shadow zone cast by the Io torus at frequencies between a few tens of kHz and about 1 MHz. Voyager also discovered narrowband kilometric radio emissions emanating from the outer edge of the torus. In this paper we will discuss expansions in the suite of satellite influences based on new observations by Galileo. These include the discovery of Ganymede's magnetosphere and evidence of radio emissions generated via mode conversion from upper hybrid waves in the frequency range of about 20 - 100 kHz. There is evidence that Ganymede may control some of the hectometric or low-frequency decametric radio emissions based on occultation measurements and statistical studies of radio emission occurrence as a function of Ganymede phase. Direction-finding measurements in the vicinity of Io suggest that a portion of the hectometric emissions may be generated near the lo L-shell. A rotationally modulated attenuation band in the hectometric emission appears to be the result of scattering at or near the Io L-shell where the waves propagate nearly parallel to the magnetic field. There is even a tantalizing hint of a Europa connection to the source of narrowband kilometric radiation.

Kurth, W. S.; Gurnett, D. A.; Menietti, J. D.

2000-01-01

57

Analysis of the Low-Frequency Radio Noise Environment at Satellite Heights from Terrestrial Sources  

NASA Astrophysics Data System (ADS)

We have investigated the propagation of terrestrial radio sources from 1 to 30 MHz (HF spectral region) through the ionosphere for the purpose of characterizing the interference spectrum on potential space-based, low-frequency-radio telescopes. A recent survey of the HF noise environment at satellite heights from 1 to 14 MHz has been conducted using the WIND spacecraft. Radio frequencies for which the interference appears to be sufficiently low for radio telescopes are 1.3, 2.9, 3.1, 8.2, and 11.4 MHz. A model was developed to predict the HF noise environment. Our current model includes a source model, an ionospheric model, and a ray tracing model. The source model was developed using known commercial broadcast stations found in the World Radio TV Handbook. The ICED ionospheric model was used to generate a model ionosphere. By ray tracing a terrestrially based broadcast source through the model ionosphere, an ionospheric transfer function (ITF) was developed. By modifying the source model using the ITF, we were able to simulate the expected noise environment at satellite heights. Comparison of modeled and measured spectra show the majority of the noise environment is due to known commercial broadcasters. Improved modeling is necessary because the slopes of the simulated spectra above the plasma frequency are too shallow, and the plasma cutoff frequencies are too high compared to the measured data.

Taylor, M. F.; Basart, J. P.; McCoy, M.; Rios, E.

1996-05-01

58

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

E-print Network

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^{20} eV, i.e. near and above the interesting GZK limit, at the very low fluxes predicted in different scenarios.

O. Stl; J. E. S. Bergman; B. Thid; L. K. S. Daldorff; G. Ingelman

2007-02-15

59

ATS-6 satellite radio beacon measurements at Ootacamund, India  

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

60

Networked Operations of Hybrid Radio Optical Communications Satellites  

NASA Technical Reports Server (NTRS)

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

Hylton, Alan; Raible, Daniel

2014-01-01

61

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

62

Detection of ultrahigh-energy cosmic rays and neutrinos by radio method using artificial lunar satellites  

Microsoft Academic Search

An estimate of the feasibility of the ultrahigh-energy cosmic ray and neutrino detection using a lunar satellite-borne radio\\u000a receiver is presented. The data obtained in the proposed experiment will make resolving the current contradictions in the\\u000a ultrahigh-energy cosmic ray spectra measured with the major ground-based instruments possible. Moreover, they will enable\\u000a us to considerably extend the accessible energy range and

G. A. Gusev; B. N. Lomonosov; K. M. Pichkhadze; N. G. Polukhina; V. A. Ryabov; T. Saito; V. K. Sysoev; E. L. Feinberg; V. A. Tsarev; V. A. Chechin

2006-01-01

63

Propagation measurements for satellite radio reception inside buildings  

NASA Technical Reports Server (NTRS)

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

Vogel, Wolfhard J.; Torrence, Geoffrey W.

1993-01-01

64

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

NASA Astrophysics Data System (ADS)

Remote sensing of radio signals from low-Earth orbiting (LEO) satellites provides a wealth of information on the presence and location of disturbances in the equatorial ionosphere which result in scintillations. Results will be presented emphasizing the statistical improvements provided to existing ionospheric specification models with the assimilation of measurements from the Coherent Electromagnetic Radio Tomography (CERTO) beacon onboard the Communication/Navigation Outage Forecasting System satellite. Spatial and temporal enhancements to regional specifications from the Scintillation Network Decision Aid (SCINDA) model are analyzed in this study carried out under solar minimum conditions in the Pacific sector. In a subset of the study covering 68 days beginning at the peak of the scintillation season, more than 60% of the events in which scintillation was observed in the C/NOFS CERTO beacon data occurred during the absence of scintillation on SCINDA VHF and GPS receivers. Oftentimes, scintillation detected on the LEO beacon signal could be directly correlated with activity later observed on a SCINDA VHF link to a geosynchronous satellite providing a forecast capability of up to two hours. Numerous cases were noted, however, in which disturbances measured during C/NOFS overflights were not observed at all on SCINDA links due to geometry constraints. Conclusions from this investigation strongly support the inclusion of radio beacon data into regional ionospheric scintillation specification and forecast models.

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

2010-12-01

65

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

NASA Technical Reports Server (NTRS)

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

Alvarez, H.

1971-01-01

66

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

67

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

NASA Technical Reports Server (NTRS)

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

Murray, C. W., Jr.

1977-01-01

68

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

NASA Astrophysics Data System (ADS)

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

Moody, Daniela I.; Smith, David A.

2014-05-01

69

Classification of satellite-based radio frequency transient recordings using sparse approximations over learned dictionaries  

NASA Astrophysics Data System (ADS)

Ongoing research at Los Alamos National Laboratory studies the Earth's radio frequency (RF) background utilizing satellite-based RF observations of terrestrial lightning. Such impulsive events occur in the presence of additive noise and structured clutter and appear as broadband nonlinear chirps at a receiver on-orbit due to ionospheric dispersion. The Fast On-orbit Recording of Transient Events (FORTE) satellite provided a rich RF lightning database. Application of modern pattern recognition techniques to this database may further lightning research and potentially improve event discrimination capabilities for future satellite payloads. We extend two established dictionary learning algorithms, K-SVD and Hebbian, for use in classification of satellite RF data. Both algorithms allow us to learn features without relying on analytical constraints or additional knowledge about the expected signal characteristics. We use a pursuit search over the learned dictionaries to generate sparse classification features and discuss performance in terms of event classification using a nearest subspace classifier. We show a use of the two dictionary types in a mixed implementation to showcase algorithm distinctions in extracting discriminative information. We use principal component analysis to analyze and compare the learned dictionary spaces to the real data space, and we discuss some aspects of computational complexity and implementation.

Moody, Daniela I.; Smith, David A.

2014-01-01

70

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

71

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

72

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

73

Unexpected Very Low Frequency (VLF) Radio Events Recorded by the Ionospheric Satellite DEMETER  

NASA Astrophysics Data System (ADS)

DEMETER was a low Earth orbiting microsatellite in operation between July 2004 and December 2010. Its scientific objective was the study of ionospheric perturbations in relation to seismic activity and man-made activities. Its payload was designed to measure electromagnetic waves over a large frequency range as well as ionospheric plasma parameters (electron and ion densities, fluxes of energetic charged particles). This paper will show both expected and unusual events recorded by the satellite when it was in operation. These latter events have been selected from the DEMETER database because they are rare or even have never been observed before, because they have a very high intensity, or because they are related to abnormalities of the experiments under particular plasma conditions. Some events are related to man-made radio waves emitted by VLF ground-based transmitters or power line harmonic radiation. Natural waves, such as atypical quasi-periodic emissions or uncommon whistlers, are also shown.

Parrot, M.; Berthelier, J. J.; Blecki, J.; Brochot, J. Y.; Hobara, Y.; Lagoutte, D.; Lebreton, J. P.; N?mec, F.; Onishi, T.; Pinon, J. L.; Pa, D.; Santolk, O.; Sauvaud, J. A.; Slominska, E.

2015-02-01

74

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

75

Product amount and quality monitoring in agricultural fields with remote sensing satellite and radio-control helicopter  

NASA Astrophysics Data System (ADS)

Product amount and quality monitoring in agricultural fields with remote sensing satellite and radio-control helicopter is proposed. In particular, tealeaves and rice crop quality and amoujnt monitorings are peoposed as examples. Nitrogen rich tealeaves tasts good. Therefore, quality of tealeaves can be estimated with nitrogen content which is related with near infrared reflectance of the tealeves in concern. Also, rice crop quality depends on protein content in rice grain which is related to near infrared reflectance of rice leaves. Therefore, product quality can be estimated with observation of near infrared reflectance of the leaves in concern. Near infared reflectance is provided by near infrared radiometers onboard remote sensing satellites and by near infrared cameras onboard radio-control helicopter. This monitoring system is applicable to the other agricultural plant products. Through monitoring near ingfrared reflectance, it is possible to estimate quality as well as product amount.

Arai, Kohei

76

Overview of techniques for mitigation of fading and shadowing in the direct broadcast satellite radio environment  

NASA Technical Reports Server (NTRS)

The DBS radio propagation environment is divided into three sub-environments, indoor, rural-suburban mobile and urban mobile. Indoor propagation effects are in a large part determined by construction material. Non-metallic materials afford direct, albeit attenuated penetration of the satellite signal with a minimum of multipath signal scattering. Signal penetration into structures using significant metallic materials is often indirect, through openings such as doors and windows and propagation will involve significant multipath components. Even so, delay spread in many situations is on the order of 10's of nanoseconds resulting in relatively flat fading. Thus frequency diversity techniques such as Orthogonal Frequency Division Multiplex (OFDM) and Code Division Multiple Access (CDMA) or equalization techniques do not realize their intended performance enhancement. Antenna diversity, directivity and placement are key mitigation techniques for the indoor environment. In the Rural-Suburban mobile environment with elevation angles greater than 20 deg, multipath components from the satellite signal are 15-20 dB below the line-of-sight signal level and often originate from nearby reflectors. Thus shadowing is the dominant signal impairment and fading effects are again found to be relatively flat for a large fading margin. Because receiver motion induces rapid variations in the signal level, temporal diversity techniques such as interleaving, channel coding and retransmission can be used to combat short intermittent fading events. Antenna diversity and directivity techniques are again useful in this environment. Finally, in the Urban mobile environment, slower vehicle speeds and blockage by buildings causes signal fades that are too long and too deep to combat with signal margin or time diversity. Land-based signal boosters are needed to fill in the coverage gaps of the satellite only broadcast scheme. On frequency boosters are suggested to conserve bandwidth yet these produce long delay multipath and create a frequency selective fading environment. Enter now OFDM, spread spectrum, equalization and other techniques that are capable of deconvolving the channel effects and effecting significant performance improvements by extracting the frequency diversity or time diversity components comprising the received signal.

Bell, David; Gevargiz, John; Vaisnys, Arvydas; Julian, David

1995-01-01

77

Sporadic structures and small-scale irregularity in the nighttime polar ionosphere in the period of high solar activity according to the data of radio occultation measurements on satellite-to-satellite paths  

Microsoft Academic Search

Results of the analysis of 327 sessions of radio occultation on satellite-to-satellite paths are presented. The data are taken\\u000a in the nighttime polar ionosphere in the regions with latitudes of 6788, and in the period of high solar activity from\\u000a October 26, 2003 to November 9, 2003. Typical ionospheric changes in the amplitude and phase of decimeter radio waves on

O. I. Yakovlev; S. S. Matyugov; V. A. Anufriev; G. P. Cherkunova

2009-01-01

78

Observations of traveling ionospheric disturbances with a satellite-beacon radio interferometer: Seasonal and local time behavior  

Microsoft Academic Search

The authors have operated a very long baseline interferometer array at a northern midlatitude site, illuminated by VHF radio beacons from two geosynchronous satellites, quasi-continuously for over a year. The array can detect and measure the trace velocity of traveling ionosphere disturbances (TIDs) via their signatures in the line-of-sight total electron content (TEC). The system noise level is of the

Abram R. Jacobson; Robert C. Carlos; Robert S. Massey; Guanghui Wui

1995-01-01

79

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

NASA Astrophysics Data System (ADS)

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

Liu, Yan; Xue, Jishan

2014-12-01

80

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

NASA Technical Reports Server (NTRS)

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.

1991-01-01

81

Forecasting ionospheric space weather with applications to satellite drag and radio wave communications and scintillation  

NASA Astrophysics Data System (ADS)

The development of quantitative models that describe physical processes from the solar corona to the Earths upper atmosphere opens the possibility of numerical space weather prediction with a lead-time of a few days. Forecasting solar wind-driven variability in the ionosphere and thermosphere poses especially stringent tests of our scientific understanding and modeling capabilities, in particular of coupling processes to regions above and below. We will describe our work with community models to develop upper atmosphere forecasts starting with the solar wind driver. A number of phenomena are relevant, including high latitude energy deposition, its impact on global thermospheric circulation patterns and composition, and global electrodynamics. Improved scientific understanding of this sun to Earth interaction ultimately leads to practical benefits. We will focus on two ways the upper atmosphere affects life on Earth: by changing satellite orbits, and by interfering with long-range radio communications. Challenges in forecasting these impacts will be addressed, with a particular emphasis on the physical bases for the impacts, and how they connect upstream to the sun and the heliosphere.

Mannucci, Anthony J.; Tsurutani, Bruce T.; Verkhoglyadova, Olga P.; Meng, Xing; Pi, Xiaoqing; Kuang, Da; Wang, Chunming; Rosen, Gary; Ridley, Aaron; Lynch, Erin; Sharma, Surja; Manchester, Ward B.; van der Holst, Bart

2015-04-01

82

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

83

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

84

Estimating water vapour along the radio path between two LEO satellites through multifrequency differential power measurements  

NASA Astrophysics Data System (ADS)

The Normalized Differential Spectral Attenuation (NDSA) concept was proposed in 2002 by the authors for tropospheric water vapour sounding by means of a couple of LEO (Low Earth Orbit) satellites (one carrying a transmitter, the other a receiver and operating in the Ku/K bands) in limb geometry. In those years, in the course of the ACE+ mission studies (second call for proposal of the ESA Earth Explorer Opportunity Mission), the problem arose of the severe impact of scintillation due to tropospheric turbulence on the water vapour estimates provided by radio occultation measurements made in limb mode between two LEO satellites. In following ESA studies (AlmetLeo - 2004, ACTLIMB -2009) it was demonstrated that NDSA, thanks to its normalised differential approach, is effective for limiting scintillation and for estimating the Integrated Water Vapor (IWV) along the propagation path between the two LEO satellites. NDSA relies on the conversion of a spectral parameter (the spectral sensitivity S), into the IWV through IWV-S relationships. S is a finite-difference approximation of the derivative of the spectral attenuation at a given frequency fo, normalized to the spectral attenuation itself. To measure Sat fo,it is required that two tone signals with equal power at relatively close frequencies f1 and f2 (f1 > f2) symmetrically placed around fo are simultaneously transmitted. The two pertinent received powers P1 and P2 are simultaneously measured and S is provided by: S = -P2--P1- (f1 - f2 )P2 From the very beginning of the NDSA studies, it was evident that in ideal measurement conditions (no disturbance at the receiver nor propagation impairments) S is tightly correlated to the IWV. To verify this, we accounted for natural variations of the atmospheric conditions by generating simulated spherically symmetric atmospheres using real radiosonde profiles. We computed IWV along the radio path and simulated S separately obtaining IWV-S relationships at various altitudes through regression methods. In particular, the ESA-AlMetLEO study yielded a significant insight into such relationships up to 12 km using the K-Ku bands, while the ESA-ACTLIMB study offered the opportunity to investigate the potential of 179 to 182 GHz (M band) for estimates from 10 km upwards, exhibiting a significant robustness to scintillation fluctuations. However, two problems affected the reliability of the empirical IWV-S relations found and have been faced by us during the on-going ESA-ANISAP study: 1) the accuracy of the radiosonde data used to derive them was not uniform in the northern and southern hemisphere, and so their positions; 2) the number of radiosonde samples above 10 km was limited, and their reliability scarce, which affected the analysis of the IWV-S relations in the M band. To overcome both problems, instead of radiosonde data, we utilized atmospheric pro?les equally distributed on a global Earth scale as derived from ECMWF atmospheric analysis data. Such database includes pressure, temperature, humidity, liquid water, ice water and wind components in 8 global datasets in 4 days amid of each of the four seasons and at two time layers (12:00 UTC and 24:00 UTC). In this work, we show the main results of the global scale analysis of the IWV-S relations up to 20 altitude. We point out that NDSA requires a multi-frequency approach to provide reliable IWV estimates up to 20 km, and that S estimates at 17, 19 and 21 GHz are essential to provide IWV profiles in the lower troposphere through linear relationships, while the M band channels (179 and 182 GHz) can be reliably exploited still through linear relationships above 10 km where the water vapour content is smaller. We also demonstrate that an additional spectral sensitivity channel at 32 GHz is very effective both to detect the presence of liquid water along the link and to correct the IWV overestimates caused by such presence when using S measurements in the K/Ku band (17, 19 and 21 GHz).

Facheris, Luca; Cuccoli, Fabrizio

2013-04-01

85

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

86

The RadioSat (sm) network  

NASA Astrophysics Data System (ADS)

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.

1991-09-01

87

An adaptive antenna system for mobile reception of digital satellite radio broadcast over TV-SAT2  

NASA Astrophysics Data System (ADS)

An adaptive antenna for mobile reception of the digital satellite radio (DSR) is presented. The DSR-Signals are transmitted via the German DBS-Satellite TV-SAT2. The four preorientated planar antenna arrays are arranged in the form of a truncated pyramid. 4-bit-phase shifters are used to control the main beam in azimuth and 1-bit-phase shifters are sufficient for the elevation range. The adaptive algorithm to control the phase shifters works in a steplike manner by gradually approaching the optimal setting. At present time the signal power at the antenna output is the optimization criterion. Measurements in the laboratory and in realistic signal environments characterize the antenna performance.

Schrewe, Hans-Juergen

88

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

NASA Astrophysics Data System (ADS)

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 22902.940.04. The mean density of Uranus is 1.2850.001 g cm-3. The satellite densities are 1.250.33 for Miranda, 1.550.22 for Ariel, 1.580.23 for Umbriel, 1.6850.068 for Titania, and 1.6350.060 for Oberon. The mean uncompressed density of all five satellites is 1.480.06 g cm-3. This is 0.10 g cm-3 higher than the value expected for a homogeneous solar mix. In order to reconcile this difference, the authors suggest that the Uranian moons contain roughly 15% by mass of pure graphite, in addition to a normal solar component of rocks and ices. If so, at least 50% of the carbon within the nebular gases from which Uranus and its satellites condensed was in the form of graphite, the remaining being in CH4. The high thermal conductivity of graphite ensures that the Uranian moons have remained cold and undifferentiated since the time of their formation, despite heating caused by the decay of radioactive nuclides. Apparently, an alternative cometary origin for the satellites is ruled out.

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

1987-12-01

89

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

E-print Network

postreturn stroke extremely low frequency (ELF) magnetic pulses, the optical emissions demonstrate. On the basis of unusual extremely low frequency (ELF) radio pulses sometimes seen in asso- ciation with sprite] Lightning remote sensing by low-frequency radio emissions is an effective technique for detecting and quan

California at Berkeley, University of

90

Design of a Software Radio Prototype for the Analysis of Beamformers in Satellite Communications  

Microsoft Academic Search

Earth stations for downloading data from LEO satellites use large reflector antennas (usually, with diameters over 12 m for telemetry links). These antennas pose a number of impairments regarding their mechanical complexity, flexibility, network efficiency (only one satellite can be tracked at a time) and cost. In order to improve the performance of traditional earth stations, the feasibility of other

Ramon Martinez Rodriguez-osorio; Alberto Bravo Sanchez; Miguel A. Salas Natera

2007-01-01

91

Notice of Violation of IEEE Publication PrinciplesA single-chip digitally enhanced radio receiver for DBS satellite TV applications  

Microsoft Academic Search

Notice of Violation of IEEE Publication Principles??A Single-chip Digitally Enhanced Radio Receiver for DBS Satellite TV Applications??by A. Maxim, R. Poorfard, R. Johnson, P. Crawley, J. Kao, Z. Dong, M. Chennam, D. Trager, M. Reidin the Proceedings of the 2008 IEEE Radio and Wireless Symposium,Page(s):787-790After careful and considered review, it has been determined that the above paper is in violation

A. Maxim; R. Poorfard; R. Johnson; P. Crawley; J. Kao; Z. Dong; M. Chennam; D. Trager; M. Reid

2008-01-01

92

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 Troms 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.; Lhr, H.; Mishin, E. V.; Roth, C.; Frolov, V. L.; Parrot, M.; Rauch, J. L.

2011-07-01

93

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

NASA Technical Reports Server (NTRS)

Phase-coherent Doppler data generated by the Deep Space Network with the radio communication system during the Voyager 2 encounter with Uranus in January 1986, optical navigation data generated by the Voyager Navigation Team with the Voyager 2 imaging system, and ground-based astrometric data obtained over an 8-yr period are compiled and analyzed to determine the masses and densities of Uranus and its principal satellites. The data-analysis procedures are explained in detail, and the results are presented in tables and graphs. The mean density of Uranus is found to be 1.285 + or - 0.001 g/cu cm, whereas the mean uncompressed mass of all five satellites is 1.48 + or - 0.06 g/cu cm, or 0.10 g/cu cm above the density expected for a homogeneous solar mix of rock, H2O and NH3 ice, and CH4 as clathrate hydrate. This difference is tentatively attributed to the presence of 15 mass percent of pure graphite, which would provide the thermal conductivity required to keep the satellites cold and undifferentiated.

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

1987-01-01

94

A Major Threat of Satellite Radio Systems in Low Earth Orbit  

NASA Technical Reports Server (NTRS)

Over the last two years several satellites in Low Earth Orbit (LEO) and geosynchronous orbit (GEO) have experienced serious or catastrophic failures including interruption of desired communications due especially to non linear interference.

Perez, R.

1999-01-01

95

Small Satellite Applications of Commercial off the Shelf Radio Frequency Integrated Circuits  

E-print Network

-spacecraft platforms to expand civil and military mission possibilities. Small spacecraft have also given small organizations such as universities an increased access to space. Because small satellites are limited in size, power, and mass, new and often nontraditional...

Graves, John

2012-02-14

96

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

97

Radio Detection of Thunderstorm Activity With an Earth-Orbiting Satellite  

Microsoft Academic Search

The radio .astronomy explorer satdlite (RAE 1) measures noise temperatures at an altitude of about 6000 km on frequencies from 0.2 to 9.2 MHz. By taking into account the effects of ionospheric shielding on terrestrial noise propagating to RAE 1 from the earth's surface it is shown that on frequencies above the critical frequency the noise observed by RAE 1

John R. Herman; Robert G. Stone; Joseph A. Caruso

1975-01-01

98

Guided radio-wave propagation in the equatorial ionosphere according to the Intercosmos-19 and Alouette/ISIS satellites  

NASA Astrophysics Data System (ADS)

In addition to normal vertical-incident ionogram traces, strongly remote (up to 2000 km), traces of HF-radio-signal reflections observed on topside-sounder ionograms of the Interkosmos-19 satellite obtained in the equatorial ionosphere are presented. Such traces are connected with waveguides (ducts). These waveguides are field-aligned irregularities of ionospheric plasma with electron density depletion of a few percent and cross-field dimension of a few to several kilometers. Ray tracing confirms this supposition and allows an estimate of the typical parameters of the waveguides. The waveguide traces usually start at the cutoff frequency of the main trace. However, sometimes they begin at much lower frequencies which indicate the waveguides are located in plasma bubbles. Only one ducted trace is usually observed on the Interkosmos-19 ionograms; a second conjugate trace is rarely recorded. Waveguides are observed at all heights of Interkosmos-19 (500-1000 km) inside the equatorial anomaly region (from -40 to +40 degrees DipLat). Ducted-echo characteristics observed with the Interkosmos-19 are different from those observed earlier with the Alouette and ISIS satellites. This difference is discussed. It is shown that the ionospheric plasma irregularities responsible for the waveguides are observed much more often during nighttime than during daytime.

Karpachev, Alexander; Zhbankov, Gennadii; Telegin, Viktor; Kuleshova, Valentina

99

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

100

User applications unique to mobile satellites  

NASA Technical Reports Server (NTRS)

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

Castiel, David

1990-01-01

101

Coronal magnetic field and the plasma beta determined from radio and multiple satellite observations  

E-print Network

We derived the coronal magnetic field, plasma density, and temperature from the observation of polarization and intensity of radio thermal free-free emission using the Nobeyama Radioheliograph (NoRH) and extreme ultraviolet (EUV) observations. We observed a post-flare loop on the west limb 11 April 2013. The line-of-sight magnetic field was derived from the circularly polarized free-free emission observed by NoRH. The emission measure and temperature were derived from the Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO). The derived temperature was used to estimate the emission measure from the NoRH radio free-free emission observations. The derived density from NoRH was larger than that determined using AIA, which can be explained by the fact that the low temperature plasma is not within the temperature coverage of the AIA filters used in this study. We also discuss the other observation of the post-flare loops by the EUV Imager onboard the Solar Terrestrial Relations Observatory (...

Iwai, Kazumasa; Nozawa, Satoshi; Takahashi, Takuya; Sawada, Shinpei; Kitagawa, Jun; Miyawaki, Shun; Kashiwagi, Hirotaka

2014-01-01

102

Coronal magnetic field and the plasma beta determined from radio and multiple satellite observations  

NASA Astrophysics Data System (ADS)

We derived the coronal magnetic field, plasma density, and temperature from the observation of polarization and intensity of radio thermal free-free emission using the Nobeyama Radioheliograph (NoRH) and extreme ultraviolet (EUV) observations. We observed a post-flare loop on the west limb on 11 April 2013. The line-of-sight magnetic field was derived from the circularly polarized free-free emission observed by NoRH. The emission measure and temperature were derived from the Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO). The derived temperature was used to estimate the emission measure from the NoRH radio free-free emission observations. The derived density from NoRH was larger than that determined using AIA, which can be explained by the fact that the low-temperature plasma is not within the temperature coverage of the AIA filters used in this study. We also discuss the other observation of the post-flare loops by the EUV Imager onboard the Solar Terrestrial Relations Observatory (STEREO), which can be used in future studies to reconstruct the coronal magnetic field strength. The derived plasma parameters and magnetic field were used to derive the plasma beta, which is a ratio between the magnetic pressure and the plasma pressure. The derived plasma beta is about 5.7 10-4 to 7.6 10-4 at the loop top region.

Iwai, Kazumasa; Shibasaki, Kiyoto; Nozawa, Satoshi; Takahashi, Takuya; Sawada, Shinpei; Kitagawa, Jun; Miyawaki, Shun; Kashiwagi, Hirotaka

2014-12-01

103

Direct conversion of light to radio frequency energy. [using photoklystrons for solar power satellites  

NASA Technical Reports Server (NTRS)

A description is presented of the test results obtained with the latest models of the phototron. The phototron was conceived as a replacement for the high voltage solar cell-high power klystron combination for the solar power satellite concept. Physically, the phototron is a cylindrical evacuated glass tube with a photocathode, two grids, and a reflector electrode in a planar configuration. The phototron can be operated either in a biased mode where a low voltage is used to accelerate the electron beam produced by the photocathode or in an unbiased mode referred to as self-oscillation. The device is easily modulated by light input or voltage to broadcast in AM or FM. The range of operation of the present test model phototrons is from 2 to 200 MHz.

Freeman, J. W.; Simons, S.

1981-01-01

104

Mass distribution of the Leonid meteoroid stream and satellite threat by systematic radio observations  

NASA Astrophysics Data System (ADS)

A comprehensive survey of the results from joint campaigns of the Leonid meteoroid stream observed on Novembers of 1995-2000 by the BLM (Bologna-Lecce-Modra) forward scatter radar is given in terms of structural aspects and stream mass-distribution variations in connection with satellite threat. Trends of long duration echoes and variations of reflection time exhibit a multiple peak activity, which is seen to be associated to a filamentary structure of the Leonid meteoroid stream. The particle density/stream width relationship is found to match observations of IRAS (Infrared Astronomical Satellite) dust trails of short-period comets. The mass distribution indices of the Leonid meteoroids in coincidence with the peak activity, are shown to change significantly throughout the 6-year observational period in agreement with visual findings. A representation of extended components of larger particles in 1996 and mainly in 1998, and of relatively smaller particles during the minor meteor storm of 1999, is evidenced. The consequences of meteoroid high fluxes and low mass indices in 1998-2000 are examined in relation to spacecraft interactions and effects. The different values of the mass indices for the 1966 and 1999 storm meteoroids might account for the comparable critical impact probability values determined for these two years as a function of the exposed area of space platforms. On the basis of the measured fluxes, critical impact probabilities for the 1995-2000 years appear to be generally low even for large extension orbiting structures, but prospects for storm encounters are from 2001 and 2002.

Pupillo, G.; Cevolani, G.; Trivellone, G.

2001-10-01

105

The Establishment at Pittsburg State University of Radio Station KRPS Affiliated with National Public Radio and Supported by the Corporation for Public Broadcasting.  

ERIC Educational Resources Information Center

This description of the establishment of KRPS--a public radio station--at Pittsburg State University in Kansas, focuses on the strategies pursued to acquire the necessary approvals to construct the station, the problems encountered in its construction, and information on costs, equipment, and budgeting. Seven appendixes provide additional

Smoot, Joseph G.

106

Measurement of the amplitude and phase fluctuation spectrum of satellite signals in the case of the action of high-power radio waves on the ionosphere  

Microsoft Academic Search

Artificial ionospheric irregularities produced by high-power radio-frequency heating were investigated by measuring signals from NNSSA satellites at the coherent frequencies 150 and 400 MHz. Spectral processing of the data indicates the existence of two spectrum types of artificial irregularities excited by high-power short waves: (1) a spectrum with a monotonic power dependence and (2) a spectrum with a peak in

F. I. Vybornov; L. M. Erukhimov; G. P. Komrakov; V. I. Kosolapenko; V. A. Kriazhev

1986-01-01

107

INSTRUMENTS AND METHODS OF INVESTIGATION Ice satellites of planets of the Solar System and the on-orbit radio detection of ultrahigh-energy particles  

NASA Astrophysics Data System (ADS)

The problem of detecting nature's most energetic particlescosmic rays and neutrinosis reviewed. Prospects for using orbital radio detectors for these highest-energy particles are examined. Apertures are calculated for space experiments using the Moon and similar-sized ice satellites of planets of the Solar System as targets for the interaction of cosmic-ray particles and neutrinos. A comparative analysis shows that using the Moon as a target is the most promising scenario.

Gusev, G. A.; Lomonosov, B. N.; Ryabov, Vladimir A.; Chechin, V. A.

2010-12-01

108

Observations of traveling ionospheric disturbances with a satellite-beacon radio interferometer: Seasonal and local time behavior  

SciTech Connect

The authors have operated a very long baseline interferometer array at a northern midlatitude site, illuminated by VHF radio beacons from two geosynchronous satellites, quasi-continuously for over a year. The array can detect and measure the trace velocity of traveling ionosphere disturbances (TIDs) via their signatures in the line-of-sight total electron content (TEC). The system noise level is of the order of 10{sup 13} m{sup {minus}2} in the TEC, so that even very weak perturbations can be studied. They have used the year-long TID detection/velocimetry data set to describe local time and seasonal dependences of the wave parameters. The most striking finding is that the preferred azimuths of TIDs in the data set tend to belong to either of two modes: The first mode, strongest at midday and in the early afternoon, particularly around winter equinox, propagates southward. The second mode, strongest in the evening, especially during summer solstice through autumn equinox, propagates west-northwestward. The two modes are disposed in local time such as to suggest the agency of clockwise rotation of the TID preferred azimuths versus time, as expected by wind filtering in the thermospheric diurnal tide. However, there is a gap between the two modes` azimuth bands. Moreover, the two modes exist in all trace-speed quartiles of the data set TIDs, a finding which is at variance with the hypothesis of wind filtering being the primary explanation of these modes. 28 refs., 13 figs.

Jacobson, A.R.; Carlos, R.C.; Massey, R.S.; Wui, Guanghui [Los Alamos National Lab., NM (United States)] [Los Alamos National Lab., NM (United States)

1995-02-01

109

The application of a bistatic intersystem interference model to radio systems co-ordination and satellite systems optimization  

NASA Astrophysics Data System (ADS)

This paper presents results from a new theoretical model to estimate bistatic rain scatter interference between terrestrial radio relay systems and earth-satellite systems operating at the same frequency. The current model used by the CCIR was developed in the early 1970s when system packing density was low and the large earth-station antennas allowed the consideration of narrow beam approximations. This resulted in a small common volume of intersection of the two beams and large circular contours. The recent increase in microwave communications traffic and the improvements in technology have meant that very small aperture terminals (VSATs) can be employed, and hence the model must allow for the consideration of sidelobes, low gain antennas and non-uniform rain cells intersecting much larger common volumes. Aspects of the new model are discussed and different assumptions made by the CCIR model are examined. Results from the new model show that the contours are smaller and non-circular and result in much smaller coordination areas.

McGuinness, R.

1993-02-01

110

Satellite radio occultation investigations of internal gravity waves in the planetary atmospheres  

NASA Astrophysics Data System (ADS)

Internal gravity waves (IGWs) modulate the structure and circulation of the Earths atmosphere, producing quasi-periodic variations in the wind velocity, temperature and density. Similar effects are anticipated for the Venus and Mars since IGWs are a characteristic of stably stratified atmosphere. In this context, an original method for the determination of IGW parameters from a vertical temperature profile measurement in a planetary atmosphere has been developed [Gubenko et al., 2008, 2011, 2012]. This method does not require any additional information not contained in the profile and may be used for the analysis of profiles measured by various techniques. The criterion for the IGW identification has been formulated and argued. In the case when this criterion is satisfied, the analyzed temperature fluctuations can be considered as wave-induced. The method is based on the analysis of relative amplitudes of the wave field and on the linear IGW saturation theory in which these amplitudes are restricted by dynamical (shear) instability processes in the atmosphere. When the amplitude of an internal wave reaches the shear instability threshold, energy is assumed to be dissipated in such a way that the IGW amplitude is maintained at the instability threshold level as the wave propagates upwards. We have extended the developed technique [Gubenko et al., 2008] in order to reconstruct the complete set of wave characteristics including such important parameters as the wave kinetic and potential energy per unit mass and IGW fluxes of the energy and horizontal momentum [Gubenko et al., 2011]. We propose also an alternative method to estimate the relative amplitudes and to extract IGW parameters from an analysis of perturbations of the Brunt-Vaislala frequency squared [Gubenko et al., 2011]. An application of the developed method to the radio occultation (RO) temperature data has given the possibility to identify the IGWs in the Earth's, Martian and Venusian atmospheres and to determine the magnitudes of key wave parameters such as the intrinsic frequency, amplitudes of vertical and horizontal wind velocity perturbations, vertical and horizontal wavelengths, intrinsic vertical and horizontal phase (and group) speeds, kinetic and potential energy per unit mass, vertical fluxes of the wave energy and horizontal momentum. Vertical profiles of temperature retrieved from RO measurements of the CHAMP (Earth), Mars Global Surveyor (Mars), Magellan and Venus Express (Venus) missions are used and analyzed to identify discrete or narrow spectral wave events and to determine IGW characteristics in the Earths, Martian and Venusian atmospheres. This work was partially supported by the RFBR grant 13-02-00526-? and Program 22 of the RAS Presidium. References. Gubenko V.N., Pavelyev A.G., Andreev V.E. Determination of the intrinsic frequency and other wave parameters from a single vertical temperature or density profile measurement // J. Geophys. Res. 2008. V. 113. No.D08109, doi:10.1029/2007JD008920. Gubenko V.N., Pavelyev A.G., Salimzyanov R.R., Pavelyev A.A. Reconstruction of internal gravity wave parameters from radio occultation retrievals of vertical temperature profiles in the Earths atmosphere // Atmos. Meas. Tech. 2011. V. 4. No.10. P. 2153-2162, doi:10.5194/amt-4-2153-2011. Gubenko V.N., Pavelyev A.G., Salimzyanov R.R., Andreev V.E. A method for determination of internal gravity wave parameters from a vertical temperature or density profile measurement in the Earths atmosphere // Cosmic Res. 2012. V. 50. No.1. P. 21-31, doi: 10.1134/S0010952512010029.

Kirillovich, Ivan; Gubenko, Vladimir; Pavelyev, Alexander

111

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

112

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

113

Radio data transmission for SCADA  

SciTech Connect

Enron has used such wireless systems as meteor burst radio, 952 MHz multiple address radio, VSAT and L-band satellite, cellular radio and ACSB radio. The company's experience with meteor burst radio communications is discussed in this paper. It indicates good system reliability and consequently all back-up telephone lines have been removed from sites using this system.

Frasier, W.E. (Enron Corp., Houston, TX (US))

1989-09-01

114

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

NASA Technical Reports Server (NTRS)

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

1990-01-01

115

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

NASA Technical Reports Server (NTRS)

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

1990-01-01

116

[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

117

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

118

75 FR 47141 - Review of Personal Radio Services Rules  

Federal Register 2010, 2011, 2012, 2013, 2014

...in the Meteorological Aids, Meteorological Satellite, or Earth Exploration Satellite Services. MedRadio stations must accept any...in the Meteorological Aids, Meteorological Satellite, or Earth Exploration Satellite...

2010-08-04

119

Atmospheric Climate Change Detection by Radio Occultation Data Using a Fingerprinting Method  

E-print Network

Atmospheric Climate Change Detection by Radio Occultation Data Using a Fingerprinting Method Navigation Satellite System (GNSS) radio occultation (RO) provides a novel record of high into practice. The Global Navigation Satellite System (GNSS) radio occultation (RO) technique allows the re

120

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

121

Opportunities and Challenges of Nano Satellites  

E-print Network

Opportunities and Challenges of Nano Satellites August, 2010 Rei Kawashima AXELSPACE Corporation #12;2 AXELSPACE - Who are we? Space venture company specialized in nano-satellites. Developer of nano-satellites conceptual design, manufacture, testing, launch to satellite operation Established in 8/8/2008. Young

122

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

ERIC Educational Resources Information Center

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

Pizzi, Skip

123

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

124

(Astro)Physics 343 Observational Radio Astronomy  

E-print Network

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

Baker, Andrew J.

125

Methods of satellite oceanography  

NASA Technical Reports Server (NTRS)

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

Stewart, R. H.

1985-01-01

126

Radio Astronomy Radio astronomy  

E-print Network

Effelsberg 100m telescope (Germany) Green Bank 100m telescope (National Radio Astronomy ObservatoryExperiment -10m (Chile, Europe) #12;Submillimeter radio astronomy #12;Size of telescope Snow sweep at Nobeyama 45;#12;Arecibo 300m telescope #12;Radio interferometer #12;Radio interferometer Very Large Array (VLA) (New

Metchev, Stanimir

127

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

128

Radio Galaxies.  

ERIC Educational Resources Information Center

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

Downes, Ann

1986-01-01

129

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

130

Radio Science, Volume ???, Number , Pages 131, Radio tomography of the ionosphere: Analysis  

E-print Network

Radio Science, Volume ???, Number , Pages 1­31, Radio tomography of the ionosphere: Analysis AND CRESPON: 4D IONOSPHERE TOMOGRAPHY After analysing the forward and inverse problems of radio tomography, the development of Faraday rotation measurements on-board satellites opens the way to magnetospheric radio

Garcia, Raphaël

131

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

Code of Federal Regulations, 2014 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....

2014-04-01

132

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

Code of Federal Regulations, 2011 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....

2011-04-01

133

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

Code of Federal Regulations, 2012 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....

2012-04-01

134

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

135

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

Federal Register 2010, 2011, 2012, 2013, 2014

...satellite digital audio radio services' use of the ephemeral recordings statutory license...Copyright, Digital audio transmissions...Performance right, Sound recordings. Final Regulations...REPRODUCTION OF EPHEMERAL RECORDINGS BY PREEXISTING SUBSCRIPTION...SATELLITE DIGITAL AUDIO RADIO SERVICES...

2010-02-03

136

Satellite (IRLS) tracking of elk  

NASA Technical Reports Server (NTRS)

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

Buechner, H. K.

1972-01-01

137

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

138

Mobile satellite communications for consumers  

NASA Astrophysics Data System (ADS)

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

Noreen, Gary K.

1991-11-01

139

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

140

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.

141

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

142

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

143

Corporal punishment.  

PubMed

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

Zolotor, Adam J

2014-10-01

144

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

145

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

Code of Federal Regulations, 2014 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...

2014-10-01

146

Compact private hubs for corporate VSAT networks  

NASA Astrophysics Data System (ADS)

Satellite communications has played a significant role in making information networks a strategic corporate asset. Very small aperture terminal (VSAT) networks, in particular, have special appeal for the corporate network user community because of unique advantages in cost, operations, and user control. The recent rapid proliferation of these networks in a multitude of market segments, as diverse as retail and financial services, is evidence of their wide acceptance for business communications.

Shimabukuro, Tom M.; Subbarayan, Ravi

147

Mobile satellite regulation in the United States  

NASA Technical Reports Server (NTRS)

During the last decade, the U.S. FCC has developed the regulatory structure for the provision of mobile services via satellite. In May 1989, the FCC awarded American Mobile Satellite Corporation (AMSC) a license to provide the full range of domestic mobile satellite services in the U.S. At that time, the FCC reaffirmed the U.S. mobile satellite industry structure and spectrum allocations that had been adopted previously. Also in May 1989, the FCC authorized the Communications Satellite Corporation (COMSAT), the U.S. Signatory to Inmarsat, to provide international aeronautical satellite service via the Inmarsat system. Earlier in 1989, the FCC permitted the use of Ku-band satellites to provide messaging and tracking services. In the mid-1980's, the FCC established the Radiodetermination Satellite Service and awarded licenses. Among the mobile satellite matters currently facing the FCC are whether additional spectrum should be allocated for domestic 'generic' mobile satellite services, the regulatory structure for the provision of mobile satellite service on an interim basis before AMSC launches its dedicated satellites, and whether to authorize a low earth orbit satellite system to provide mobile data service.

Levin, Lon C.; Sonnenfeldt, Walter H.

1990-01-01

148

Satellite Communication.  

ERIC Educational Resources Information Center

Presents a discussion of communication satellites: explains the principles of satellite communication, describes examples of how governments and industries are currently applying communication satellites, analyzes issues confronting satellite communication, links mathematics and science to the study of satellite communication, and applies

Technology Teacher, 1985

1985-01-01

149

Corporation for Public Broadcasting: Mission and Goals, Tasks and Responsibilities.  

ERIC Educational Resources Information Center

This brochure contains two statements adopted by the Corporation for Public Broadcasting (CPB), one outlining the Corporation's mission and goals, and the other outlining its tasks and responsibilities. The mission of the CPB is to take the lead in developing a uniquely American non-commercial public radio and television system that will inform,

Corporation for Public Broadcasting, Washington, DC.

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

Strategies for corporate governance in engineering corporations  

Microsoft Academic Search

Although corporate governance plays a crucial role in shaping the vision, image and reputation of a corporation, this subject has been largely ignored in the prevailing engineering and technology management literature. In the wake of scandals like Enron and WorldCom, the call for effective corporate governance echoes across the boardrooms of many corporations. It is the intent of this paper

Karim S. Rebeiz

2002-01-01

152

Satellite oceanography - The instruments  

NASA Technical Reports Server (NTRS)

It is pointed out that no instrument is sensitive to only one oceanographic variable; rather, each responds to a combination of atmospheric and oceanic phenomena. This complicates data interpretation and usually requires that a number of observations, each sensitive to somewhat different phenomena, be combined to provide unambiguous information. The distinction between active and passive instruments is described. A block diagram illustrating the steps necessary to convert data from satellite instruments into oceanographic information is included, as is a diagram illustrating the operation of a radio-frequency radiometer. Attention is also given to the satellites that carry the various oceanographic instruments.

Stewart, R. H.

1981-01-01

153

Planning considerations for domestic replacement satellites  

NASA Astrophysics Data System (ADS)

Some aspects of the emerging multipurpose domestic satellite, which carries fixed and mobile services, TV direct broadcasting, and radio position determination, are discussed against a background of network digitalization, network expansion, circuit compression, and synchronization. Particular attention is given to transponder supply and demand, satellite replenishment, Ku-band versus C-band for TV direct satellite broadcasting, choice of modulation/multiple access for mobile communication, and expected accuracy in radio position determination. It is noted that the payload size and number of satellites per given time period depend on the type of service and on the applied transmission period.

Johannsen, Klaus G.

1987-09-01

154

Corporate strategy and the Social Networking phenomena  

Microsoft Academic Search

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

Robert L. Johnson

2010-01-01

155

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

156

Radio telescopes  

Microsoft Academic Search

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

J. Findlay

1964-01-01

157

Corporate Governance and Accountability  

Microsoft Academic Search

This book chapter on Corporate Governance and Accountability is a contribution to the book CORPORATE GOVERNANCE - SYNTHESIS OF THEORY, RESEARCH, AND PRACTICE (Wiley, forthcoming 2010), edited by Ronald Anderson and H. Kent Baker. This chapter describes the sources of corporate governance standards for American corporations and analyzes the accountability mechanisms designed to ensure that corporate officials act faithfully in

Renee M Jones

2010-01-01

158

Notice of Violation of IEEE Publication PrinciplesA Zero-Second-IF SiGe BiCMOS Satellite Radio Tuner Using a Single PLL for Both RF and IF LO Generation and a Replica Ring-VCO Calibrated IF Filter  

Microsoft Academic Search

Notice of Violation of IEEE Publication Principles??A Zero-Second-IF SiGe BiCMOS Satellite Radio Tuner Using a Single PLL for Both RF and IF LO Generation and a Replica Ring-VCO Calibrated IF Filter??by Maxim, A.; Gheorge, M.; Turinici, C.;in the Proceedings of the IEEE Bipolar\\/BiCMOS Circuits and Technology Meeting, 2007. BCTM '07.Sept. 30 2007-Oct. 2 2007 Page(s):1 - 4After careful and considered

A. Maxim; M. Gheorge; C. Turinici

2007-01-01

159

Solar Power Satellite (SPS) pilot beam and communication link subsystem investigation study, phase 1. [ionospheric propagation, radio frequency interference, and microwave transmission  

NASA Technical Reports Server (NTRS)

A preliminary engineering model of ionospheric interactions with the pilot beam was established and used to demonstrate that the dual frequency baseline pilot beam system might not be viable in the presence of an unstable transmission path. Alternate approaches to remove this difficulty are described. Although ionospheric fluctuations will not significantly degrade beam pointing or raise the sidelobe levels, they will reduce transmission efficiency by upwards of 25%. Mitigating strategies to substantially reduce this effect are proposed. Based on the Klystron noise spectrum, the pilot beam transmitter power was determined as a function of frequency offset from the power beam carrier frequency. The RFI from the pilot beam, on the ground and at geosynchronous orbit is shown. Noise levels on the earth's surface due to the SPS are presented as a function of frequency and the number of SPS systems. Analysis of the communication subsystem indicates that a standard telemetry line of 1.544 MB/s would satisfy both voice and data link requirements. Additional links would be required for TV and radio transmissions.

1979-01-01

160

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.

161

Satellite observations of transionospheric pulse pairs  

Microsoft Academic Search

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 μsec, are typically 20 to 40 dB brighter than the average

D. N. Holden; C. P. Munson; J. C. Devenport

1995-01-01

162

25 CFR 213.14 - Corporations and corporate information.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Corporations and corporate information. 213.14 Section 213...Leases 213.14 Corporations and corporate information. If the applicant...showing compliance with the corporation laws thereof. Statements of changes in...

2010-04-01

163

25 CFR 226.8 - Corporation and corporate information.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Corporation and corporate information. 226.8 Section 226...Royalty 226.8 Corporation and corporate information. (a) If the applicant...showing compliance with the corporation laws thereof. (b) Whenever deemed...

2010-04-01

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

Radio imaging of Jupiter's magnetosphere with LOFAR  

Microsoft Academic Search

Jupiter emits intense decameter radio waves, detectable from the ground in the range ~10 to 40 MHz. They are produced by energetic electron precipitations in its auroral regions, as well as near the magnetic footprints of the galilean satellite Io. Radio imaging imaging of these decameter emissions with arcsecond angular resolution and millisecond time resolution should give access to: -

P. Zarka

2003-01-01

166

Stimulation of Jupiter's Radio Emission by Io  

Microsoft Academic Search

Variations in the decameter radio signals from Jupiter are known to be associated with one of the planet's five satellites. It is now suggested that Io travels in the analogue of the inner Van Allen radiation belt surrounding Jupiter, giving rise to a plasma wake which streams ahead of it by about 130,000 km and stimulates the radio emission from

L. Marshall; W. F. Libby

1967-01-01

167

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

168

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.

169

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

170

Irregularities in ionospheric plasma clouds: Their evolution and effect on radio communication  

Microsoft Academic Search

Both satellite radio communications, which travel through the Earth's ionosphere, and high frequency (HF) sky wave circuits, which use the ionosphere as a refracting medium, can be strongly affected by radio wave scintillation. High altitude nuclear explosions cause scintillation (by strongly disturbing the ionosphere) and thus severely degrade satellite radio communications over a large region. Since further atmospheric nuclear tests

J. F. Vesecky; J. W. Chamberlain; J. M. Cornwall; D. A. Hammer; F. W. Perkins

1980-01-01

171

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

172

Radio Ghosts  

E-print Network

We investigate the possibility that patches of old radio plasma (`radio ghosts') of former radio galaxies form a second distinct phase of the inter-galactic medium (IGM), not mixed with the thermal gas. The separation of this phase from the ambient gas and its resistance against eroding turbulent forces is given by magnetic fields, which are expected to be roughly in pressure equilibrium with the surrounding medium. Since patches of this plasma are largely invisible in the radio we use the term `radio ghost' to characterize their nature. Possibilities and difficulties of different detection strategies of ghosts are discussed. These involve radio emission, cosmic microwave background (CMB) and starlight Comptonization, and Faraday rotation. Re-activation of the electron population in shock waves of cosmological structure formation, which seems to lead to the cluster radio relic phenomena. We discuss the role radio ghosts can have: They are able to store relativistic particles for cosmological times, but are al...

Ensslin, T A

1999-01-01

173

An integrated mobile satellite broadcast, paging, communications and navigation system  

NASA Astrophysics Data System (ADS)

The present integrated mobile satellite broadcast, paging, communications and navigation system will use Ku-band and Radiosat ground stations to broadcast digital audio signals and data packets to mobile receivers via a satellite scheduled for launch in 1993. Each mobile radio simultaneously receives L-band digital audio and data broadcasts from GPS through a common omnidirectional mobile antenna and receiver front end. Radiosat mobile radios will employ the GPS broadcasts and differential corrections through the satellite with 2-m accuracy.

Noreen, Gary K.

1990-12-01

174

Radio Astronomy  

NSDL National Science Digital Library

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

Tenenbaum, David

175

Cognitive radio: Making software radios more personal  

Microsoft Academic Search

Software radios are emerging as platforms for multiband multimode personal communications systems. Radio etiquette is the set of RF bands, air interfaces, protocols, and spatial and temporal patterns that moderate the use of the radio spectrum. Cognitive radio extends the software radio with radio-domain model-based reasoning about such etiquettes. Cognitive radio enhances the flexibility of personal services through a Radio

Joseph Mitola; Gerald Quentin Maguire Jr.

1999-01-01

176

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.

177

How Satellite Observations Impact NWP  

NSDL National Science Digital Library

Satellite observations have a huge impact on numerical weather prediction (NWP) model analyses and forecasts, with sounding data from polar orbiting and GPS-radio occultation satellites reducing model forecast error by almost half. All of this despite the fact that NWP models only assimilate 5% of all satellite observations! This lesson discusses the use of satellite observations in NWP and how model limitations prevent more of the data from being assimilated. The lesson begins by briefly describing the history of satellite observations in NWP and their impact on NWP model forecast skill. The next part provides background information about the types of environmental satellites that provide input to NWP, the satellite observations that are assimilated, the major components of NWP models, and how they forecast atmospheric behavior. This sets the stage for the main part of the lesson, which examines how observations from new satellite instruments are vetted for inclusion in data assimilation systems and how observations deemed acceptable are actually assimilated. The final part describes current challenges to making optimal use of satellite observations in NWP and advances that are expected to address these challenges and improve model forecasts.

COMET

2014-03-12

178

Discovering corporate consciousness  

Microsoft Academic Search

This paper attempts to first define the concept of corporate consciousness and to locate it within a nomological net of related concepts. It is found that corporate consciousness may be an identifiable concept, but its differentiation from such related constructs as corporate social responsibility is unclear. Second, some methodological issues related to the study of corporate consciousness are discussed such

Michael A. Campion; David K. Palmer

1996-01-01

179

LDEF Satellite Radiation Analyses  

NASA Technical Reports Server (NTRS)

This report covers work performed by Science Applications International Corporation (SAIC) under contract NAS8-39386 from the NASA Marshall Space Flight Center entitled LDEF Satellite Radiation Analyses. The basic objective of the study was to evaluate the accuracy of present models and computational methods for defining the ionizing radiation environment for spacecraft in Low Earth Orbit (LEO) by making comparisons with radiation measurements made on the Long Duration Exposure Facility (LDEF) satellite, which was recovered after almost six years in space. The emphasis of the work here is on predictions and comparisons with LDEF measurements of induced radioactivity and Linear Energy Transfer (LET) measurements. These model/data comparisons have been used to evaluate the accuracy of current models for predicting the flux and directionality of trapped protons for LEO missions.

Armstrong, T. W.; Colborn, B. L.

1996-01-01

180

TCP, PEP and DTN performance on disruptive satellite channels  

Microsoft Academic Search

Fixed GEO satellite communications are impaired by long RTTs and the possible presence of packet losses on the satellite radio channel. Moreover, when the satellite receiver is mobile, short and long disruptions due to line of sight obstructions can cause further performance deterioration. In this paper, we present a preliminary assessment of disruption impact on performance comparing different approaches, such

C. Caini; P. Cornice; R. Firrincieli; M. Livini; D. Lacamera

2009-01-01

181

Developing a MANET radio for the advanced robotic controller  

Microsoft Academic Search

In conjunction with Exponent Corporation, Sensoria Corporation has developed and demonstrated a secure MANET radio for the U.S. Army's Rapid Equipping Force. This paper summarizes the capabilities of that system, demonstrated with up to forty-three radios. This system is based on an 802.11b physical layer, upon which mobile ad hoc routing, and secure communication has been layered. It provides a

W. Merill; Aidan Doyle; Rocco Costanza; Josef Kriegl; Lew Girod; Bud Patterson

2004-01-01

182

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

183

Digene Corporation.  

PubMed

Digene Corporation is a molecular diagnostics company that develops, manufactures and markets proprietary gene-based testing systems for the screening, monitoring and diagnosis of human diseases. The company's primary focus is in women's cancers and infectious diseases. Our proprietary, patented Hybrid Capture((R)) technology has been successfully applied to the development of diagnostic tests for human papillomavirus (HPV), Chlamydia, Gonorrhea, hepatitis B virus and cytomegalovirus. Digene's Hybrid Capture 2 (hc2) trade mark HPV DNA test has now been established as part of the standard of care for cervical cancer screening in the US. We are focusing our research and development activities on support and improvement of existing product lines as well as the development of several new products. We have several ongoing basic research programs with the goal of developing improved molecular diagnostic assay systems for the detection of HPV and other targets of interest in the area of women's cancers and infectious diseases. Digene's goal is to establish primary screening by the Hybrid Capture HPV DNA Test as the worldwide standard of care for cervical cancer screening. PMID:14683424

Obiso, Richard; Lorincz, Attila

2004-01-01

184

The Rapidly Deployable Radio Network  

E-print Network

. Frost, Fellow, IEEE, Ben Ewy, Ricardo Sanchez, Craig Sparks, Member, IEEE, K. Malinimohan, James Roberts, Senior Member, IEEE, Richard Plumb, Senior Member, IEEE, and Dave Petr, Senior Member, IEEE AbstractThe Rapidly Deployable Radio Network (RDRN...-223, with funding from Sprint Corporation and the State of Kansas. J. B. Evans, G. J. Minden, K. S. Shanmugan, G. Prescott, V. S. Frost, R. Sanchez, C. Sparks, J. Roberts, R. Plumb, and D. Petr are with the In- formation and Telecommunication Technology Center...

Evans, Joseph B.; Minden, Gary J.; Shanmugan, K. S.; Prescott, Glenn Eugene; Frost, Victor S.; Ewy, Ben; Sanchez, R; Sparks, Craig; Malinimohan, K.; Roberts, James A.; Plumb, R. G.; Petr, Dave

1999-04-01

185

Evaluation of CHAMP radio occultation refractivity using data assimilation office analyses and radiosondes  

E-print Network

Evaluation of CHAMP radio occultation refractivity using data assimilation office analyses occultation experiment on the CHAMP satellite has been collecting observations of the Earth's atmosphere since candidate than geometrical optics and back-propagation for generating GPS radio occultation datasets

Joiner, Joanna

186

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

E-print Network

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

Gwinn, Carl

187

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

188

Radio wave.  

PubMed

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

Elkin, V

1992-01-01

189

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.

190

Radio Ghosts  

E-print Network

We investigate the possibility that patches of old radio plasma (`radio ghosts') of former radio galaxies form a second distinct phase of the inter-galactic medium (IGM), not mixed with the thermal gas. The separation of this phase from the ambient gas and its resistance against eroding turbulent forces is given by magnetic fields, which are expected to be roughly in pressure equilibrium with the surrounding medium. Since patches of this plasma are largely invisible in the radio we use the term `radio ghost' to characterize their nature. Possibilities and difficulties of different detection strategies of ghosts are discussed. These involve radio emission, cosmic microwave background (CMB) and starlight Comptonization, and Faraday rotation. Re-activation of the electron population in shock waves of cosmological structure formation, which seems to lead to the cluster radio relic phenomena. We discuss the role radio ghosts can have: They are able to store relativistic particles for cosmological times, but are also able to release them under the influence of very strong turbulence. This might happen during a major merger event of clusters of galaxies. The released relativistic proton population could produce the observed radio halos of some cluster of galaxies via hadronic reactions with the background gas leading to the production of secondary electrons and positrons. Destroyed ghosts, mixed with the IGM can help to magnetize it. Finally, the strong field strength within ghosts should have a significant impact on the propagation of extragalactic high energy cosmic rays.

Torsten A. Ensslin

1999-06-11

191

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

192

Essays on corporate bonds  

E-print Network

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

Bao, Jack (Jack C.)

2009-01-01

193

ENGAGING UNH Corporate Resources  

E-print Network

ENGAGING UNH Corporate Resources www.unh.edu/corporateresources Strategic relationships to connect the University's educational, research, and outreach mission with your corporate or company goals 2007 Connecting.Relations.and.Philanthropy CAREER RESOURCES, INTERNSHIPS, FELLOWSHIPS

New Hampshire, University of

194

Corporate Governance and Taxation  

E-print Network

links between corporate tax avoidance and private benefitscorporate governance system, and the equilibrium level of tax avoidance.corporate resources. We validate this assumption by investigating an environment Russia where both tax avoidance

Dyck, Alexander

2004-01-01

195

Corporate sustainability assessment methodology  

E-print Network

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

Pinchuk, Natallia

2011-01-01

196

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

197

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.

198

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.

199

Radio Traffic  

Microsoft Academic Search

The functions of the traffic department of a radio company, namely: procuring and moving traffic, procuring equipment contracts, and operating ship and shore stations economically and efficiently, are described. In connection with the work of the Marconi Company, the cooperation between the Western Union and Postal Telegraph Companies and the radio company is treated in detail. The complete routine procedure

D. Sarnoff

1914-01-01

200

Scaling the Corporate Heights.  

ERIC Educational Resources Information Center

Reviews "Black Life in Corporate America" (Davis and Watson), "Women at Work: A Psychologist's Secrets to Getting Ahead in Business" (Senter), and "The Black Manager, Making It in the Corporate World" (Dickens and Dickens). All three books address general issues confronting Black/female managers, and two offer guidance to corporate newcomers. (CMG)

Campbell, Bebe Moore

1983-01-01

201

Basiselemente Corporate Design  

E-print Network

Farbspektrums. #12;Corporate Design t Sekundrfarben Beispiele passiver Farbergnzungen Beispiele aktiver Paderborn. Basisfarbe1Pantone281Blau Basisfarbe2Pantone420Grau #12;Corporate Design t Passive;Corporate Design t Definition passiver Zusatzfarben Farben Definition von Farbtnen fr ein passives

Hellebrand, Sybille

202

Corporate governance & IT  

Microsoft Academic Search

Known for its international approach to corporate governance and its accessible nature, Corporate Governance has established itself as an invaluable text for both undergraduate and postgraduate students. Chris Mallin introduces the reader to the theories and development of corporate governance, before looking at owners and stakeholders and directors, all the time illustrating the theory with examples from the press and

Michael S. Weisbach; Francis E. Warnock; Rohan Williamson

1996-01-01

203

VLBI observations of geosynchronous satellites  

NASA Astrophysics Data System (ADS)

The principle of determining spacecraft angular position with differential VLBI (Very Long Baseline Interferometry) technique is described. The first domestic differential VLBI observations of geosynchronous satellites were performed with participations of Shanghai, Urumqi and Kunming stations. Three strong quasars within angular separation of 15 from target satellites were selected as reference radio sources. The main purpose of such observations is to obtain interferometric fringes of the satellites, and to estimate accuracy of differential VLBI observations. A 2-station FX type correlator at SHAO (Shanghai Astronomical Observatory) was used to do cross-correlations of radio signals in MK3A-C tape format. Strong fringes of the satellites were detected to all stations. The precision of time delay and rate was derived from the correlator output. Based on system errors analysis, we estimated that ?DOR (Delta Differential One-way Ranging) error was about 41 cm, and ?DOD (Delta Differential One-way Doppler) error was about 0.148mm/s, which corresponded, respectively, to the position error of 8m and the velocity error of 2.8mm/s for the geosynchronous satellite on the plane of sky.

Shu, Fengchun; Zhang, Xiuzhong; Zheng, Weimin

204

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.

2013-08-30

205

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,

206

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

207

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

208

The American mobile satellite system  

NASA Technical Reports Server (NTRS)

During 1989, the American Mobile Satellite Corporation (AMSC) was authorized to construct, launch, and operate satellites to provide mobile satellite services (MSS) to the U.S. and Puerto Rico. The AMSC has undertaken three major development programs to bring a full range of MSS services to the U.S. The first program is the space segment program that will result in the construction and launch of the satellites as well as the construction and installation of the supporting ground telemetry and command system. The second segment will result in the specification, design, development, construction, and installation of the Network Control System necessary for managing communications access to the satellites, and the specification and development of ground equipment for standard circuit switched and packet switched communications services. The third program is the Phase 1 program to provide low speed data services within the U.S. prior to availability of the AMSC satellites and ground segment. Described here are the present status and plans for these three programs as well as an update on related business arrangements and regulatory matters.

Garner, William B.

1990-01-01

209

Radio Telescopes  

NASA Astrophysics Data System (ADS)

``Radio Telescopes" starts with a brief historical introduction from Jansky's1931 discovery of radio emission from the Milky Way through the development ofradio telescope dishes and arrays to aperture synthesis imaging. It includessufficient basics of electromagnetic radiation to provide some understanding of thedesign and operation of radio telescopes. The criteria such as frequencyrange, sensitivity, survey speed, angular resolution, and field of view thatdetermine the design of radio telescopes are introduced. Because it is soeasy to manipulate the electromagnetic waves at radio frequencies, radiotelescopes have evolved into many different forms, sometimes with "wire"structures tuned to specific wavelengths, which look very different from anykind of classical telescope. To assist astronomers more familiar with otherwavelength domains, the appendix A.1. includes a comparison of radioand optical terminology. Some of the different types of radio telescopesincluding the filled aperture dishes, electronically steered phased arrays, andaperture synthesis radio telescopes are discussed, and there is a sectioncomparing the differences between dishes and arrays. Some of the morerecent developments including hierarchical beam forming, phased arrayfeeds, mosaicing, rotation measure synthesis, digital receivers, and longbaseline interferometers are included. The problem of increasing radiofrequency interference is discussed, and some possible mitigation strategies areoutlined.

Ekers, Ron; Wilson, Thomas L.

210

ECS - The European Communication Satellite system  

NASA Astrophysics Data System (ADS)

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

Wooster, C. B.

1981-09-01

211

Configuration development of the Land Mobile Satellite System (LMSS) Spacecraft  

NASA Technical Reports Server (NTRS)

Configurations for a Land Mobile Satellite System Spacecraft are discussed. It is a preliminary concept of a quad aperture reflector spacecraft capable of relaying radio messages to land mobile units throughout the United States.

Golden, C. T.; Lackey, J. A.; Spear, E. E.

1982-01-01

212

Satellite Imagery  

NSDL National Science Digital Library

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

John Nielsen-Gammon

1996-01-01

213

Satellite Images  

NSDL National Science Digital Library

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

214

CB Radios  

ERIC Educational Resources Information Center

Citizen band radios keep trucking across the American scene, and no doubt your students are caught in the folk craze. Provides some suggestions for channeling students' interests with a unit on CBs. (Author/RK)

Martin, Dick

1977-01-01

215

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

216

Managing Mobile/Satellite Propagation Data  

NASA Technical Reports Server (NTRS)

"Data Management System for Mobile Satellite Propagation" software package collection of FORTRAN programs and UNIX shell scripts designed to handle huge amounts of data resulting from mobile/satellite radio-propagation experiments. Data from experiments converted into standard and more useful forms. Software package contains program to convert binary format of data into standard ASCII format suitable for use with wide variety of computing-machine architectures. Written in either FORTRAN 77 or UNIX shell scripts.

Kantak, Anil V.

1990-01-01

217

Leo satellite-based telecommunication network concepts  

NASA Technical Reports Server (NTRS)

Design considerations are discussed for Low Earth Orbit (LEO) satellite based telecommunications networks. The satellites are assumed to be connected to each other via intersatellite links. They are connected to the end user either directly or through gateways to other networks. Frequency reuse, circuit switching, packet switching, call handoff, and routing for these systems are discussed by analogy with terrestrial cellular (mobile radio) telecommunication systems.

Aiken, John G.; Swan, Peter A.; Leopold, Ray J.

1991-01-01

218

Satellite Threat Warning and Attack Reporting  

Microsoft Academic Search

The Air Force Research Laboratory`s Satellite Threat Warning and Attack Reporting (STW\\/AR) program will provide technologies for advanced threat warning and reporting of radio frequency (RF) and laser threats. The STW\\/AR program objectives are: (a) develop cost- effective technologies to detect, identify, locate, characterize, and report attacks or interference against U.S. and Allied satellites. (b) demonstrate innovative, light-weight, low-power, laser

D. Hilland; G. Phipps; C. Jingle; G. Newton

1997-01-01

219

Satellite threat warning and attack reporting  

Microsoft Academic Search

The Air Force Research Laboratory's Satellite Threat Warning and Attack Reporting (STW\\/AR) program will provide technologies for advanced threat warning and reporting of radio frequency (RF) and laser threats. The STW\\/AR program objectives are: (1) Develop cost-effective technologies to detect, identify, locate, characterize, and report attacks or interference against U.S. and Allied satellites. (2) Demonstrate innovative, lightweight, low-power, RF and

D. H. Hilland; G. S. Phipps; C. M. Jingle; G. Newton

1998-01-01

220

78 FR 59633 - Wireless Telecommunications Bureau Opens Docket To Seek Comment on DISH Network Corporation's...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Extension of Time filed by DISH Network Corporation (``DISH Request...September 9, 2013, the DISH Network Corporation, on behalf of...DISH, which is also the Mobile Satellite Service licensee...necessary for DISH to update its network and device planning to...

2013-09-27

221

Preface: International Reference Ionosphere and Global Navigation Satellite Systems  

NASA Astrophysics Data System (ADS)

The International Reference Ionosphere (IRI) is a joint undertaking by the Committee on Space Research (COSPAR) and the International Union of Radio Science (URSI) with the goal of developing and improving an international standard for the specification of Earth's ionosphere. This endeavor was originally triggered by the need for an ionosphere model for the satellite/experiment design and satellite data analysis (COSPAR) and for radio propagation studies (URSI) but has meanwhile found a much broader range of users with space weather concerns.

Bilitza, Dieter; Reinisch, Bodo

2015-04-01

222

Radio astronomy  

Microsoft Academic Search

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)

Kenneth I. Kellermann; David Heeschen; Donald C. Backer; Marshall H. Cohen; Michael Davis; Imke de Pater; David De Young; George A. Dulk; J. R. Fisher; W. Miller Goss

1991-01-01

223

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

224

Analysis and Modeling of Jovian Radio Emissions Observed by Galileo  

NASA Technical Reports Server (NTRS)

Our studies of Jovian radio emission have resulted in the publication of five papers in refereed journals, with three additional papers in progress. The topics of these papers include the study of narrow-band kilometric radio emission; the apparent control of radio emission by Callisto; quasi-periodic radio emission; hectometric attenuation lanes and their relationship to Io volcanic activity; and modeling of HOM attenuation lanes using ray tracing. A further study of the control of radio emission by Jovian satellites is currently in progress. Abstracts of each of these papers are contained in the Appendix. A list of the publication titles are also included.

Menietti, J. D.

2003-01-01

225

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

226

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

227

Satellite systems for Latin American telecommunication requirements  

NASA Astrophysics Data System (ADS)

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

Elizondo, Eduardo L.

228

Radio occultation data analysis by the radioholographic method  

Microsoft Academic Search

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

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

1999-01-01

229

Radio Tagged Adult Female Walrus on Ice Floe  

USGS Multimedia Gallery

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

230

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

ERIC Educational Resources Information Center

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

Texas Education Agency, Austin.

231

"Globalstar, Iridium and other Satellite-Based Mobile Phone  

E-print Network

tubes], radio was ­ Primarily broadcast ­ Receivers were fixed locations or automobiles · In the 70's's, satellites were ­ Mostly geosynchronous earth orbit or GEO ­ Invaluable for relay and broadcast of the LEO · Mobile phones have small, omni antenna ­ Could not reach existing GEO satellites ­ Could reach

232

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.

2012-08-03

233

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

234

Entering the Corporate Market.  

ERIC Educational Resources Information Center

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

Greenshields, Garry W.

235

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

236

The Corporate Law Curriculum  

ERIC Educational Resources Information Center

On the premise that corporate counsel must be an able diagnostician before he can focus on highly specialized and interrelated issues of business law, the author suggests an approach to corporate law curriculum in which the basic course balances the quality and quantity of material designed to create the needed sensitivity. (JT)

Mofsky, James S.

1976-01-01

237

Making the Corporate Connection.  

ERIC Educational Resources Information Center

Corporate sponsorship is a marketing strategy by which companies communicate about their products or services by affiliating with events or institutions valued by targeted customer groups. Increasingly, campus communicators are seeking to establish corporate sponsorships but first must resolve legal and ethical concerns. Various types of

Cornforth, Suzanne; Simpson, Kristen

1999-01-01

238

Bottle Rock Power Corporation  

E-print Network

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

239

Bank Community Development Corporations.  

ERIC Educational Resources Information Center

This handbook provides a brief overview of bank and bank holding company community development corporations (CDCs), the types of activities for which they can be used, the legal requirements in establishing such an entity, and how they are organized and operated. Case studies, including studies of the Shorebank Corporation of Chicago, the First

Illinois State Dept. of Commerce and Community Affairs, Springfield.

240

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

241

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

NASA Astrophysics Data System (ADS)

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

Pinglier, A.

1980-02-01

242

77 FR 45352 - Radio Broadcasting Services; AM or FM Proposals To Change the Community of License  

Federal Register 2010, 2011, 2012, 2013, 2014

...BROADCATING CORPORATION, Station WRSV, Facility ID 54823, BPH-20120530AFQ, From ROCKY MOUNT, NC, To ELM CITY, NC; SIERRA RADIO, INC., Station KVXX, Facility ID 31618, BPH- 20101004ACX, From QUINCY, CA, To CONCOW, CA. DATES:...

2012-07-31

243

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

244

The seasonal cycle of planetary boundary layer depth determined using COSMIC radio occultation data  

E-print Network

The seasonal cycle of planetary boundary layer depth determined using COSMIC radio occultation data, and Climate (COSMIC) satellite mission. COSMIC uses GPS radio occultation to derive the vertical profile), The seasonal cycle of planetary boundary layer depth determined using COSMIC radio occultation data, J. Geophys

Wood, Robert

245

A School Radio Telescope for Two Metres  

ERIC Educational Resources Information Center

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

Codling, J. C.

1973-01-01

246

Radio astronomy at Stanford  

NASA Astrophysics Data System (ADS)

Many astronomical topics were addressed by students and staff of the Stanford Radio Astronomy Institute over the course of decades, and some of the memorable milestones can be discussed here at length. These are antenna design and construction, the sunspot number series, astronomical tomography, the cosmic microwave background radiation, nulling interferometry for peering into circumstellar environments, celestial mechanics of the early Earth satellites, the extraterrestrial connection, dynamic spectra of exospheric phenomena, the versatile Hartley transform and Centaurus A. In addition to the text references, a complete list of solar publications related to the microwave spectroheliograph is appended. Further detail, and non-solar publications, are available in the annual reports published in the Astronomical Journal and Bulletin American Astronomical Society from 1961 to1980, especially the final report.

Bracewell, R. N.

2005-12-01

247

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

248

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

249

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

250

The monarchy as a corporate brand : Some corporate communications dimensions  

Microsoft Academic Search

Purpose The purpose of this paper is to examine the role of corporate communications on behalf of the monarchy as a corporate brand. Design\\/methodology\\/approach Draws on the preliminary findings of a major study on monarchies. Findings Argues that corporate communications is an important aspect of corporate brand management (especially in relation to constitutional monarchies). Research implications

Stephen A. Greyser; John M. T. Balmer; Mats Urde

2006-01-01

251

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.

252

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

253

Virtual Satellite  

NASA Technical Reports Server (NTRS)

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

Hammrs, Stephan R.

2008-01-01

254

Domestic mobile satellite systems in North America  

NASA Technical Reports Server (NTRS)

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

Wachira, Muya

1990-01-01

255

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

E-print Network

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

Williams, Brian C.

256

Essays in corporate finance  

E-print Network

This dissertation presents three essays in Corporate Finance. In the first essay, I study managerial incentives in internal capital markets. In particular, I develop a two-tiered agency model to study division managers' ...

Motta Gregori, Adolfo de, 1970-

2001-01-01

257

Encyclopedia of Corporate Governance  

NSDL National Science Digital Library

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

258

The Development of a Materials Distribution Service for a Satellite-Based Educational Telecommunications Experiment. Satellite Technology Demonstration, Technical Report No. 0501.  

ERIC Educational Resources Information Center

Because 16mm film programs for classroom use are expensive and distribution is unpredictable, the Satellite Technology Demonstration (STD) established a Materials Distribution Service (MDS) to transmit material via satellite to rural sites in the Rocky Mountains. The STD leased 300 programs from Encyclopedia Britannica Educational Corporation and

Lonsdale, Helen C.

259

Radio Variability of Radio Quiet and Radio Loud Quasars  

E-print Network

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 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.

Richard Barvainis; Joseph Lehar; Mark Birkinshaw; Heino Falke; Katherine M. Blundell

2004-09-22

260

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.

261

The Arctic Regional Communications Small SATellite (ARCSAT)  

NASA Technical Reports Server (NTRS)

Traditional satellite missions are extremely complex and expensive to design, build, test, launch and operate. Consequently many complementary operational, exploration and research satellite missions are being formulated as a growing part of the future space community capabilities using formations of small, distributed, simple to launch and inexpensive highly capable small scale satellites. The Arctic Regional Communications small SATellite (ARCSAT) initiative would launch a Mini-Satellite "Mothership" into Polar or Sun Sync low-earth-orbit (LEO). Once on orbit, the Mothership would perform orbital insertion of four internally stored independently maneuverable nanosatellites, each containing electronically steerable antennas and reconfigurable software-defined radios. Unlike the traditional geostationary larger complex satellite communication systems, this LEO communications system will be comprised of initially a five small satellite formation that can be later incrementally increased in the total number of satellites for additional data coverage. ARCSAT will provide significant enabling capabilities in the Arctic for autonomous voice and data communications relay, Maritime Domain Awareness (MDA), data-extraction from unattended sensors, and terrestrial Search & Rescue (SAR) beacon detection missions throughout the "data starved desert" of the Arctic Region.

Casas, Joseph; Kress, Martin; Sims, William; Spehn, Stephen; Jaeger, Talbot; Sanders, Devon

2013-01-01

262

Hindawi Publishing Corporation EURASIP Journal on Applied Signal Processing  

E-print Network

) and an online phase (i.e., mobile position estimation). In the off-line phase, a "radio-map" of the environment in the outdoor environment, where the line-of-sight propagation paths to GPS satellites exist. However, it cannot 51673, Pages 1­13 DOI 10.1155/ASP/2006/51673 Application of Beamforming in Wireless Location Estimation

263

Telecommunications Radio Lease  

E-print Network

Telecommunications Radio Lease 1. Fax completed form to 979.847.1111. 2. If you do not receive. Note: There is an air time charge for the use of the radios. Radio lease rates depend on the radio type to any of the radios, chargers and accessories until signed back over to the Telecommunications office

264

Educational Radio. What the Research Says. A Literature Survey. Internal Report.  

ERIC Educational Resources Information Center

This review of the literature on educational radio covers reports on research from many areas of the world. Prepared as an internal report for the South African Broadcasting Corporation (SABC) and Educational Radio and Television (ERTV), it was intended to provide a basis for both fruitful discussions and more specific and practical local

Duby, Aliza

265

ASUSat1: the development of a low-cost satellite  

Microsoft Academic Search

In October 1993, the students at Arizona State University (ASU) were challenged by Orbital Sciences Corporation to develop a 4.5-kg (10-lb) satellite (ASUSat1) to be launched as a piggyback payload on a Pegasus rocket. The challenge included the requirements for the satellite to perform meaningful science and to fit inside the Pegasus avionics section (0.033 m diam. X 0.027 m).

Shea Ferring; Joel D. Rademacher; Assi Friedman; David Waller; Helen L. Reed

1997-01-01

266

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

E-print Network

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

267

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.

268

Radio Jove: Jupiter Radio Astronomy for Citizens  

NASA Astrophysics Data System (ADS)

Radio JOVE is a hands-on educational activity that brings the radio sounds of the Sun, Jupiter, the Milky Way Galaxy, and terrestrial radio noise to students, teachers, and the general public. Participants may build a simple radio telescope kit, make scientific observations, and interact with professional radio observatories in real-time over the Internet. Our website (http://radiojove.gsfc.nasa.gov) includes science information, construction manuals, observing guides, and education resources for teachers and students. Radio Jove is continually expanding its participants with over 1800 kits sold to more than 70 countries worldwide. Recently some of our most dedicated observers have upgraded their Radio Jove antennas to semi-professional observatories. We have spectrographs and wide band antennas, some with 8 MHz bandwidth and some with dual polarization capabilities. In an effort to add to the science literature, these observers are coordinating their efforts to pursue some basic questions about Jupiters radio emissions (radio source locations, spectral structure, long term changes, etc.). We can compare signal and ionosphere variations using the many Radio Jove observers at different locations. Observers are also working with members of the Long Wavelength Array Station 1 (LWA1) radio telescope to coordinate observations of Jupiter; Radio Jove is planning to make coordinated observations while the Juno Mission is active beginning in 2015. The Radio Jove program is overviewed, its hardware and software are highlighted, recent sample observations are shown, and we demonstrate that we are capable of real citizen science.

Higgins, Charles; Thieman, J. R.; Flagg, R.; Reyes, F. J.; Sky, J.; Greenman, W.; Brown, J.; Typinski, D.; Ashcraft, T.; Mount, A.

2014-01-01

269

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

270

For internal use only Corporate Banking & Securities: Corporate Finance  

E-print Network

and other key emerging markets. Together, we drive forward innovative solutions that lead the global banking industry. About Corporate Finance Part of Deutsche Bank's Corporate Banking & Securities (CB&S) division

Scholz, Bernhard

271

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.

272

Master of Science in Corporate Communication Corporate Communication  

E-print Network

and corporate culture, it partners human resources specialists; in communicating with customers, it collaborates access to strate- gic resources. In this it is a strategic partner of other corporate functions with marketers, etc. Corporate communication specialists therefore need to acquire solid general management

Krause, Rolf

273

The integration of corporate governance in corporate social responsibility disclosures  

Microsoft Academic Search

In recent years, not only has attention to corporate governance increased but also the notion has broadened considerably, and started to cover some aspects traditionally seen as being part of corporate social responsibility (CSR). CSR, corporate governance and their interlink seem particularly relevant for multinational enterprises (MNEs), which, due to their activities in multiple contexts around the world and concomitant

A. Kolk; J. Pinkse

2010-01-01

274

Corporate social responsibility: an attitude of Ethiopian corporates  

Microsoft Academic Search

Purpose The purpose of this research is to find an attitude of Ethiopian corporate sector towards corporate social responsibility (CSR). In addition this research analyzed the opinion of employees, customers' as well the general public about the Ethiopian corporate sector's socially responsible actions. Design\\/methodology\\/approach This paper reviewed the relevant literature of CSR. Through structured questionnaires and in-depth interviews

Rajasekhara Mouly Potluri; Zelalem Temesgen

2008-01-01

275

Corporations and the financing of innovation: The corporate venturing experience  

Microsoft Academic Search

During the past forty years, the media and academics have frequently maligned corporate investments in venture capital and highlighted visible failures. Many corporations' best ideas have languished, whether because of internal resistance or an inability to execute on the initial insight. In other cases, more nimble companies, often venture-backed start-ups, have turned corporations' innovative ideas into commercial successes. So how

Paul A. Gompers

2002-01-01

276

2009 IBM Corporation 2009 IBM Corporation IMS and Java  

E-print Network

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

277

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.

2012-08-03

278

COGNITIVE RADIO APPLICATIONS IN SOFTWARE DEFINED RADIO  

Microsoft Academic Search

The topic of cognitive radios has been garnering a great deal of attention in the past several years. Opinions regarding the level of sophistication necessary to qualify a system as cognitive vary widely, and discussions have ensued regarding this technology. The software defined radio forum is also involved and has working group activity in the area of cognitive radio. Some

John Polson

2004-01-01

279

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

280

The Illiquidity of Corporate Bonds  

E-print Network

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

Bao, Jack

281

Corporate governance and insider trading  

E-print Network

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

Rozanov, Konstantin A

2008-01-01

282

A Survey of Corporate Governance  

Microsoft Academic Search

This article surveys research on corporate governance, with special attention to the importance of legal protection of investors and of ownership concentration in corporate governance systems around the world. Copyright 1997 by American Finance Association.

Andrei Shleifer; Robert W Vishny

1997-01-01

283

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.

284

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

285

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

286

Corporal Punishment and the Schools.  

ERIC Educational Resources Information Center

In order to understand and evaluate the continued prevalence of corporal punishment in school systems, this article reviews the following topics: (1) historical issues; (2) current demographics and correlates; (3) the effectiveness of corporal punishment in school settings; (4) myths; (5) alternatives to corporal punishment; and (6) social policy.

Bauer, Gordon B.; And Others

1990-01-01

287

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

288

Corporate Affiliate Event Details  

E-print Network

Counsel Institute Affiliate Program? Affiliates of the Corporate Counsel Institute (CCI) are law firms, and most other states. #12; CCI draws up to 150 participants from around the country The majority Institute Contact Peter Skrabacz (312) 503-4213 peter.skrabacz@law.northwestern.edu #12;2013 CCI Firm

Shahriar, Selim

289

The Corporate Classroom.  

ERIC Educational Resources Information Center

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

Stenger, Richard S.

1991-01-01

290

Pinnacle West Capital Corporation  

E-print Network

Power Park Pinnacle West Capital Corporation #12;Objectives Economic hydrogen production Renewable new technology Solar reforming of natural gas Low cost electrolysis opportunities Identify hydrogen storage models Chemical by-product management model Pilot Solar reforming of natural gas model #12

291

The corporate trustee evolution  

SciTech Connect

Trustees have an increasing role in the public debt market for project finance. With the responsibility comes the need for clearly defined guidelines. This article examines the need for public financing of power projects, and the role and responsibilities of corporate trustees in this environment.

Joiner, B.A.; Ross, M.D.

1994-03-01

292

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

293

Corporate Energy Management Process  

E-print Network

-05-25 Proceedings of the Thrity-Fifth Industrial Energy Technology Conference New Orleans, LA. May 21-24, 2013 BASF North America BASF Corporation (U.S.), BASF Canada, BASF Mexicana ESL-IE-13-05-25 Proceedings of the Thrity-Fifth Industrial Energy Technology...

Geiger, T.

2013-01-01

294

Corporate Management Invades Academe.  

ERIC Educational Resources Information Center

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

Nielsen, Robert M.

295

Signalling characteristics in satellite-aided land mobile communications  

NASA Technical Reports Server (NTRS)

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

Anderson, R. E.

1982-01-01

296

The Cassini Radio Science Observations of the Enceladus Plasma Cloud  

NASA Astrophysics Data System (ADS)

Cassini Radio Science Subsystem (RSS) observations of the plasma environment of Enceladus from the radio occultation of 26 January 2006 are reported. The radio occultation technique was used to measure the electron content as a function of distance along a the orbital path of Enceladus with the radio line-of-sight passing about 45 km below the South Pole. The RSS observations, when applied to a toroidal model of a plasma cloud along the orbit of Enceladus show a significant enhancement of the electron density, extending out to distances from the satellite in excess of 88 Enceladus radii in both directions. Simple estimates show that this is consistent with a photoionization plasma source together with transport away from the satellite due to the plasma flow. In addition, the occultation data shows an electron density depletion near the plume, in agreement with other instruments, and this is possibly due to electron attachment to grains.

Kliore, A. J.; Nagy, A. F.; Cravens, T.; Anabtawi, A.

2013-12-01

297

Extended Extragalactic Radio Emission  

E-print Network

Extended radio emission and its relation to parent galaxy properties is briefly reviewed. Our current understanding of the relation between absolute radio and optical luminosity, radio morphology and linear size is discussed. The impact of radio jets on dense cluster cores is discussed using M87 as an example. Finally, the relation of AGN's to star-bursting galaxies at high redshift is considered.

F. N. Owen; M. J. Ledlow; J. A. Eilek; N. E. Kassim; N. A. Miller; K. S. Dwarakanath; R. J. Ivison

2000-06-11

298

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

299

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

300

Using a co-located GNSS radio occultation payload for microwave radiometer calibration  

E-print Network

This study presents a new method of calibrating an orbital cross-track scanning microwave radiometer using a co-located radio occultation (RO) instrument with Global Navigation Satellite Systems (GNSS). The radiometer and ...

Dav, Pratik K. (Pratik Kamlesh)

2014-01-01

301

Modulate Internet Radio Into FM Using GNU Radio  

E-print Network

1 Modulate Internet Radio Into FM Using GNU Radio By: Elie Salameh Outline. · Fm in gnu radio · Audio Streams in Internet Radio · Gnu & Audio Files · Sox command · Playlist ".pls" · Recording internet radio #12;2 Project description · Using gnu radio to modulate internet radio into fm. · Using usrp

Yu, Chansu

302

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

303

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

304

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

305

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

306

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

307

Telecommunications Radio Rental  

E-print Network

Telecommunications Radio Rental 1. Fax completed form to 979.847.1111. 2. If you do not receive://telecom.tamu.edu/Accounts/Rate_Information.php). There is an air time charge for the use of the radios. Rental radios will be pro-rated per radio per daily usage of the radios, chargers and accessories until signed back over to the Telecommunications office. Amount

308

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

309

Youth Radio  

NSDL National Science Digital Library

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

310

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

311

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

312

The Submillimeter Wave Astronomy Satellite: instrument hardware.  

NASA Astrophysics Data System (ADS)

The Submillimeter Wave Astronomy Satellite (SWAS) will study Galactic star formation and interstellar chemistry through a survey of dense molecular clouds in five astrophysically important transitions of H2O, H218O, O2, C I, and 13CO. To carry out this mission the SWAS instrument and spacecraft are designed to embody all the elements of a ground-based radio telescope. The "instrument" portion of the satellite is comprised of: (1) the antenna, (2) two heterodyne receivers, (3) an acousto-optical spectrometer, (4) the thermal control system, (5) the instrument control electronics, (6) the star tracker, and (7) the instrument structure. The "spacecraft" portion of the satellite is comprised of: (1) the attitude control system (ACS), (2) the solar arrays and power regulating hardware, (3) the onboard command, data, and ACS computer, (4) the solid-state memory for data recording, and (5) all data uplink and downlink receivers and transmitters. This contribution discusses the instrument hardware.

Tolls, V.; Melnick, G. J.; Erickson, N.; Goldsmith, P.; Harwit, M.; Schieder, R.; Snell, R. L.; Stauffer, J. R.

313

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

314

Benchmarking Corporate Energy Management  

E-print Network

's energy management procedures and perfonnance compare to that of other companies. Energy management involves everything from setting goals and targets to implementing best maintenance practices. This paper, however, discusses benchmarking energy... co-authored by me for the IETC 2000 titled "Corporate Energy Management: A Survey of Large Manufacturing Companies," eight elements of best energy management practice were presented and data on the energy management practices of 23 companies...

Norland, D. L.

315

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

316

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

317

Small satellites: cost methodologies and remote sensing issues  

NASA Astrophysics Data System (ADS)

Increasing interest in small satellites has generated a need for detailed information regarding the capabilities and costs of such systems. Of specific interest are comparisons of the cost- effectiveness of small satellites for remote sensing applications with the more traditional large satellites. An additional issue is whether small satellite acquisition philosophies actually enable cost reductions at acceptable levels of risk. To address these issues a series of studies has been conducted at The Aerospace Corporation over the past five years. A large database of cost, technical, and performance characteristics has been assembled for small satellites actually flown or in late stages of development. A small satellite cost model (SSCM) has been derived from this database with cost-estimating relationships (CERs) based largely on small satellite performance characteristics. Associated risk analysis techniques and cost-engineering models (CEMs) have also been formulated, with the SSCM functioning as the central engine for cost analysis of small satellite approaches. These and other tools are applicable to a wide range of small remote sensing satellite analyses.

Abramson, Robert L.; Bearden, David A.; Glackin, David L.

1995-12-01

318

An African VLBI network of radio telescopes  

E-print Network

The advent of international wideband communication by optical fibre has produced a revolution in communications and the use of the internet. Many African countries are now connected to undersea fibre linking them to other African countries and to other continents. Previously international communication was by microwave links through geostationary satellites. These are becoming redundant in some countries as optical fibre takes over, as this provides 1000 times the bandwidth of the satellite links. In the 1970's and 1980's some two dozen large (30 m diameter class) antennas were built in various African countries to provide the satellite links. Twenty six are currently known in 19 countries. As these antennas become redundant, the possibility exists to convert them for radio astronomy at a cost of roughly one tenth that of a new antenna of similar size. HartRAO, SKA Africa and the South African Department of Science and Technology (DST) have started exploring this possibility with some of the African countries...

Gaylard, M J; Combrinck, L; Booth, R S; Buchner, S J; Fanaroff, B L; MacLeod, G C; Nicolson, G D; Quick, J F H; Stronkhorst, P; Venkatasubramani, T L

2014-01-01

319

Low-cost small satellites for astrophysical missions  

SciTech Connect

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

Priedhorsky, W.C.

1989-01-01

320

Educative Activities of the Canadian Broadcasting Corporation and the National Film Board of Canada. New Technologies in Canadian Education Series. Paper 8.  

ERIC Educational Resources Information Center

The Canadian Broadcasting Corporation (CBC) is Canada's publicly-owned broadcast network that provides programming to both English and French national television and AM/FM radio networks. While the CBC was not designed to fill a formal education role in Canada, it does broadcast informative radio and television programs on a complete range of

Swan, Susan

321

First results from an airborne GPS radio occultation system for atmospheric profiling  

E-print Network

First results from an airborne GPS radio occultation system for atmospheric profiling J. S. Haase1, Indiana, USA Abstract Global Positioning System (GPS) radio occultation (RO) from low Earth Satellite Systems Instrument System for Multistatic and Occultation Sensing (GISMOS), has been developed

Larson, Kristine

322

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

323

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

324

Tracking Data Relay Satellite System (TDRSS) VHF propagation study  

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

325

Foundation 1% Corporate 3%  

E-print Network

Archives and Records AdministrationRecords Administration The NaTioN's ReseaRch UNiveRsiTy Climate Change and predict global climate changes by analyzing sophisticated satellite data that track sea surface Commercialization 24 Research Park, Selected Research Centers and Research Profile Inside Back Cover National

Hill, Wendell T.

326

47 CFR 80.333 - Stations in the maritime mobile-satellite service.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 false Stations in the maritime mobile-satellite service. 80.333...SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Safety Watch Requirements...Procedures 80.333 Stations in the maritime mobile-satellite service. The...

2014-10-01

327

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

Microsoft Academic Search

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

N. Brady

2002-01-01

328

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

Microsoft Academic Search

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

Morio Toyoshima

2005-01-01

329

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".

330

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.

2012-08-03

331

Corporate governance and public corruption  

Microsoft Academic Search

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

Ana Cusolito

2010-01-01

332

Energy Efficient Radio Resource  

E-print Network

Energy Efficient Radio Resource Management in a Coordinated Multi-Cell Distributed Antenna System Omer HALILOGLU Introduction System Model Performance Evaluation Conclusion References Energy Efficient Hacettepe University 5 September 2014 Omer HALILOGLU (Hacettepe University) Energy Efficient Radio Resource

Yanikomeroglu, Halim

333

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

334

Radio Diaries on National Public Radio (NPR)  

NSDL National Science Digital Library

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

335

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.

336

Estimating lightning current moment waveforms from satellite optical measurements  

E-print Network

Estimating lightning current moment waveforms from satellite optical measurements Toru Adachi,1 and Duke magnetometer observed clear optical and radio signatures of 12 sprite- producing lightning events to remotely measure lightning current moment, which is critical for understanding the production of sprites

California at Berkeley, University of

337

Multiband propagation experiment for narrowband characterisation of high elevation angle land mobile-satellite channels  

NASA Astrophysics Data System (ADS)

Results of a recent multiband propagation measurement campaign for the high elevation angle land mobile satellite channel are reported. Simultaneous narrowband sounding of the channel has been carried out in suburban, wooded and open areas of the UK using a helicopter-mounted platform to simulate the satellite signal at various elevation angles. Propagation related link degradations in the land mobile-satellite channel have been observed to be less severe when the path elevation angle is increased or radio frequency decreases.

Butt, G.; Evans, B. G.; Richharia, M.

1992-07-01

338

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

339

Exotic animal corporate practice.  

PubMed

I have attempted to give insight into many of the aspects of a corporate veterinary job in the retail pet industry. Understand that these are my experiences, and corporate jobs are as diverse as the number of corporations in this field. My experiences have been positive because I have been fortunate enough to become an integral part of a company with an outstanding company ethic regarding animal care and business as a whole. This is a dream position for a veterinarian who wishes to make a far-reaching difference for animals. At PETCO I am the Animal Advocate and I do have the responsibility to look at every situation through the eyes of the animals. I take this responsibility very seriously and understand that every decision I make has a lasting impact on not only the animals we sell but also the associates who daily give their heart and soul as they care for the animals in our stores. This is the way I have chosen to make a difference in the world: by using my veterinary education as well as my life experiences in ways that are very different from the James Herriot of old-different from the advanced veterinary practices in this new millennium but steadfastly following the same principles we promised to uphold when we took the veterinary oath... Being admitted to the profession of veterinary medicine, I solemnly swear to use my scientific knowledge and skills for the benefit of society through the protection of animal health, the relief of animal suffering,the conservation of livestock resources, the promotion of public health, and the advancement of medical knowledge. I will practice my profession conscientiously, with dignity, and in keeping with the principles of veterinary medical ethics. I accept as a lifelong obligation the continual improvement of my professional knowledge and competence. PMID:16129360

Edling, Thomas M

2005-09-01

340

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

341

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

342

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

343

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.

344

Galileo radio science investigations  

Microsoft Academic Search

The radio science investigations planned for Galileo's 6-year flight to and 2-year orbit of Jupiter use as their instrument the dual-frequency radio system on the spacecraft operating in conjunction with various US and German tracking stations on Earth. The planned radio propagation experiments are based on measurements of absolute and differential propagation time delay, differential phase delay, Doppler shift, signal

H. T. Howard; V. R. Eshleman; D. P. Hinson; A. J. Kliore; G. F. Lindal; R. Woo; M. K. Bird; H. Volland; P. Edenhoffer; M. Paetzold; H. Porsche

1992-01-01

345

Cognitive Radio Architecture Evolution  

Microsoft Academic Search

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

Joseph Mitola

2009-01-01

346

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

347

Introduction Big Radio Data  

E-print Network

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

Prodiæ, Aleksandar

348

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

349

Hurricane Katrina Satellite Imagery  

NSDL National Science Digital Library

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

National Environmental Satellite, Data, and Information Service

350

MARS IONOSPHERE STUDIES USING THE MGS RADIO SCIENCE EXPERIMENT  

E-print Network

MARS IONOSPHERE STUDIES USING THE MGS RADIO SCIENCE EXPERIMENT M. Mendillo and P. Withers Center of the Mars Global Surveyor (MGS) satellite, ionospheric science at Mars depended upon a total of 433 published electron density profiles obtained over a period of about one solar cycle (1965-1976). With its

Withers, Paul

351

Radio Reflection by Free Radicals in Earth's Atmosphere  

Microsoft Academic Search

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 observations were made with the topside ionosonder of the Canadian satellite Alouette II.

J. Dale Barry; Paul J. Coleman; W. F. Libby; L. Marshall Libby

1967-01-01

352

Radio and distance learning in Pakistan.  

PubMed

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

Abbas, R

1987-01-01

353

The interrelationship between corporate income tax and corporate social responsibility  

Microsoft Academic Search

Purpose The purpose of this paper is to discuss the interrelationship between corporate income tax (CIT) and corporate social responsibility (CSR) within the international framework of the European Union (EU). Design\\/methodology\\/approach The theoretical framework of the paper is based on taxation and social responsibility theories that evaluate the impact of economic, financial and social decisions taken by firms,

Ftima David; Isabel Gallego

2009-01-01

354

Legitimation in corporate discourse: Oil corporations after Deepwater Horizon  

Microsoft Academic Search

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

Ruth Breeze

2012-01-01

355

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

356

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.

357

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 Louise.

1998-01-01

358

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; Ramn Gonzalo; Carlos del Ro

2009-01-01

359

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

360

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.

361

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.

2012-08-03

362

Tracking Weather Satellites.  

ERIC Educational Resources Information Center

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

Martin, Helen E.

1996-01-01

363

Project Leader : Kenji Esaki (Toyota Motor Corporation)  

E-print Network

Project Leader : Kenji Esaki (Toyota Motor Corporation) Research / Toyota City / National Institute of Advanced Industrial Science and Technology / Institute of Physical and Chemical Research / Asahi Glass Co., Ltd. / DENSO Corporation / Toshiba Corporation / Toyota Motor

Takahashi, Ryo

364

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

365

27 CFR 19.233 - Corporate surety.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

366

27 CFR 24.149 - Corporate surety.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

367

Corporate citizenship: Statoil.  

PubMed

Open markets alone do not guarantee equitable and sustainable development. Income disparities are growing both within and between countries to the extent that the marginalization of the poor has become a key challenge of globalization. To meet this challenge, the global community must address the governance gap between global finance/economics and local or national politics in world affairs. This article discusses how globalization is shaping Statoil's approach to corporate citizenship. The Norwegian firm, with 17,000 workers in some 25 countries, is one of the major net sellers of crude oil and supplies Europe with natural gas. Statoil maintains that corporations can contribute to global governance by conducting business in a manner that is ethical, economically viable, environmentally sound, and socially responsible. This contribution can be achieved through development partnerships with national governments, multilateral institutions, and nongovernmental organizations. Norway's Statoil ASA is one of the world's largest net sellers of crude oil and a major supplier of natural gas to Europe. It is the leading Scandinavian retailer of petroleum and other oil products. Statoil employs approximately 17,000 workers and operates in 25 countries. PMID:17208716

Fjell, Olav

2003-01-01

368

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

369

Seamless Handovers in Cobra Teardrop Satellite Arrays  

NASA Astrophysics Data System (ADS)

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

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

2007-06-01

370

The Case for Corporate Colleges.  

ERIC Educational Resources Information Center

Discusses the love/hate relationship that the human resources development community has with corporate training programs. Indicates three major objectives of effective programs: (1) build generic management skills; (2) build skills and knowledge applicable to a particular organization; and (3) forge and maintain a cohesive corporate culture. (JOW)

Gordon, Jack

1988-01-01

371

Corporate Ownership Around the World  

Microsoft Academic Search

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

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

1998-01-01

372

A Profile of Corporate Contributions.  

ERIC Educational Resources Information Center

The extent and distribution of charitable contributions by corporations were studied. In addition to a history of giving from 1936 to 1981, information is presented on corporate contributions in 1977 in terms of the distribution of companies (1) by size of contributions, (2) by contributions as percentage of net income, (3) by industry, and (4) by

Smith, Hayden W.

373

The Farm and Ranch Corporation.  

E-print Network

rooc - ~ TA245.7 1873 0.1302 The Texas A&M University System Texas Agricultural Extension Service 8-1302 Director Daniel C. Pfannstiel College Station, Texas 77843 The Farm and Ranch Corporation Farm and Ranch Busin 0 nization... in Texas CONTENTS Alternative Forms of Business Organization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3 Closely Held Farm Corporations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4...

Brints, Norman; Sartin, Marvin

1980-01-01

374

CORPORATE MERGERS, ACQUISITIONS AND DIVESTMENTS  

Microsoft Academic Search

Mergers, acquisitions and divestitures in varying forms are a central activity of corporations and partnerships which (often mistakenly) are convinced that transactions will significantly increase shareholder value due usually to synergies encompassing cost reductions, reduced capital expenditures, market expansion and occasionally to P\\/E multiple expansion. Increasingly, corporations feel that restructuring or divesting businesses will \\

Charles H. McGill

375

The Changing Shape of Corporations.  

ERIC Educational Resources Information Center

This newsletter contains two articles dealing with the changing shape of corporations. The article "Trends in Business Culture" argues that Wal-Mart's emergence as the largest corporation in the United States reflects the larger economic shift in the U.S. economy from production of goods to provision of abstract goods such as services and

Wagner, June G.

2003-01-01

376

Corporate Social Responsibility in China  

Microsoft Academic Search

Current understandings of corporate social responsibility practices and attitudes have been mainly driven by 'western-centric' data and philosophical approaches. China is undergoing a vast economic boom, and research attention is turning to the practices and attitudes of Chinese firms in regard to corporate social responsibility. The current paper used a qualitative multi-case method to examine CSR motivations, policies, and practices

Michael Ewing; Lydia Windisch

377

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

378

Corporal Punishment and Child Adjustment  

ERIC Educational Resources Information Center

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

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

2006-01-01

379

The Banning of Corporal Punishment.  

ERIC Educational Resources Information Center

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

Cryan, John R.

1995-01-01

380

The Birth of Corporate Governance  

Microsoft Academic Search

Part I of this Article briefly examines the concept of corporate governance and argues for dating the concepts origins to the debates of the 1920s. Part II then moves on to examine early scholarly and popular discussions of the separation of ownership and control. After surveying the historical developments that produced the recognizably modern corporate economy around the turn of

Harwell Wells

2010-01-01

381

Corporate personality and criminal liability  

Microsoft Academic Search

[extract] The objectives of this article are to review the dominance in the common law world of derivative models of corporate criminal liability, to examine the deficiencies that have led to the current spate of reform proposals, to describe some of these proposals, and to address certain key questions about how to construct an organizational model of corporate criminal liability.

Eric Colvin

1995-01-01

382

Compensation strategy in transnational corporations  

Microsoft Academic Search

Forces associated with globalization have facilitated the development of transnational corporations (TNCs). Such companies have a geocentric orientation and attempt to be responsive to both national markets, while simultaneously seeking global coordination. In this paper we propose that such companies need to reconsider the traditional balance sheet approach to expatriate compensation. Accordingly, we suggest that transnational corporations need to engage

Larry Phillips; Mark A. Fox

2003-01-01

383

A Survey of Corporate Governance  

Microsoft Academic Search

This article surveys research on corporate governance, with special attention to the importance of legal protection of investors and of ownership concentration in corpo- rate governance systems around the world. CORPORATE GOVERNANCE DEALS WITH the ways in which suppliers of finance to

ANDREI SHLEIFER; ROBERT W. VISHNY

1988-01-01

384

Satellite Feature Identification: Cyclogenesis  

NSDL National Science Digital Library

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

COMET

2012-08-17

385

Weather Satellite and Orbits  

NSDL National Science Digital Library

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

386

Build It Yourself: Satellite!  

NSDL National Science Digital Library

"Build It Yourself: Satellite!" is an online Flash game hosted on the James Webb Space Telescope website. The goal of the game is to explain the decision-making process of satellite design. The user can choose to build a "small," "medium," or "large" astronomy satellite. The user then selects science goals, wavelength, instruments, and optics. The satellite is then launched on the appropriate rocket (shown via an animation). Finally, the user is shown what their satellite might look like, as well as what kind of data it might collect, via examples from similar real-life satellites. Satellites range from small X-ray missions without optics (like the Rossi X-ray Timing Explorer) to large missions with segmented mirrors (like the James Webb Space Telescope).

387

Philippe Zarka Recherche de transitoires radio associs  

E-print Network

TO GW EVENTS RADIO PROPAGATION TRANSIENT RADIO SKY LOFAR TELESCOPE & OPERATING MODES LOFAR EARLY REFERENCES #12; RADIO COUNTERPARTS TO GW EVENTS RADIO PROPAGATION TRANSIENT RADIO SKY LOFAR TELESCOPEPhilippe Zarka LESIA Recherche de transitoires radio associs des ondes gravitationnelles avec

Demoulin, Pascal

388

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

Microsoft Academic Search

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

John M. T. Balmer

2001-01-01

389

The optical communication link outage probability in satellite formation flying  

NASA Astrophysics Data System (ADS)

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

Arnon, Shlomi; Gill, Eberhard

2014-02-01

390

The Solar Development Corporation  

SciTech Connect

This paper describes a proposed stand alone company, the Solar Development Corporation (SDC), to be a business development and financing entity for photovoltaic operations with the potential to be commercially sustainable. SDC will have a fully integrated policy advocacy link to the World Bank. SDC will define target countries where the potential exists for significant early market expansion. In those countries it will provide: market and business development services that will accelerate the growth of private firms and deepen the penetration of Solar Home Systems (SHS) and other rural PV applications in the market; and access to pre-commercial and parallel financing for private firms to (1) expand their capability in PV distribution businesses, and (2) strengthen their ability to provide credit to end users. SDC itself will not engage in direct financing of the final consumer. It is intended that as far as possible SDC`s finance will be provided in parallel with financing from Financial Intermediaries.

Singer, C.E.

1997-12-01

391

High Energy Astrophysics: Radio Galaxies Geoffrey V. Bicknell Radio Galaxies  

E-print Network

High Energy Astrophysics: Radio Galaxies © Geoffrey V. Bicknell Radio Galaxies 1 Fanaroff Laing #12;High Energy Astrophysics: Radio Galaxies 2/56 The prototype FR 2 radio galaxy, Cygnus A Energy Astrophysics: Radio Galaxies 3/56 Cygnus A at 850 microns. Only the hot spots and core are visible

Bicknell, Geoff

392

Spectrum agile radio: radio resource measurements for opportunistic spectrum usage  

Microsoft Academic Search

Radio spectrum allocation is undergoing radical rethinking. Regulators, government agencies, industry, and the research community have recently established many initiatives for new spectrum policies and seek approaches to more efficiently manage the radio spectrum. In this paper, we examine new approaches, namely, spectrum agile radios, for opportunistic spectrum usage. Spectrum agile radios use parts of the radio spectrum that were

Stefan Mangold; Zhun Zhong; Kiran Challapali; Chun-Ting Chou

2004-01-01

393

The 1992 World Administrative Radio Conference: Technology and Policy Implications  

NASA Astrophysics Data System (ADS)

As the 20th century draws to a close, new radio technologies and services are poised to change the ways we communicate. Radio waves already make possible a wide range of services considered commonplace--AM and FM radio broadcasting, television, cellular telephones, remote garage-door openers, and baby monitors. Advances in radio technology are giving birth to even more new products and services, including pocket-sized telephones that may allow people to make and receive calls anywhere in the world, high-definition televisions (HDTV) with superior quality pictures and sound, and static-free digital radios. The 1992 World Administrative Radio Conference (WARC-92) authorized frequencies for many of these new radio communication services, and granted additional frequencies for many existing services, including international broadcasting, satellite-based mobile communications, and communications in space. The effects of these changes will be felt well into the 21st century as countries around the world develop and deploy new communications systems to serve the needs of consumers, businesses, and governments. For the United States, the decisions made at the conference will critically affect how we develop new radio technologies and applications, how competitive this country will be in radio communications equipment and services, and how effectively the United States can exercise its role as a leader in world radio communication policymaking. This study of the outcomes and implications of WARC-92 was requested by the House Committee on Energy and Commerce and the Senate Committee on Commerce, Science, and Transportation. OTA was asked to evaluate the success of U.S. proposals at the conference, discuss the implications of the decisions made for U.S. technology and policy development, and identify options for improving U.S. participation in future world radio communication conferences.

1993-05-01

394

The nexus between ethical corporate marketing, ethical corporate identity and corporate social responsibility : An internal organisational perspective  

Microsoft Academic Search

Purpose The commentary aims to consider the nexus between corporate marketing, ethical corporate marketing, ethical corporate identity and corporate social responsibility. It seeks to take an explicit internal organisational perspective. It also aims to identify future research avenues. Design\\/methodology\\/approach The commentary explains the relevance of the previous interlinking concepts with a discussion based on a review of past

Shaun M. Powell

2011-01-01

395

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

396

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

397

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

398

25 CFR 227.6 - Corporations and corporate information.  

Code of Federal Regulations, 2012 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...

2012-04-01

399

25 CFR 227.6 - Corporations and corporate information.  

Code of Federal Regulations, 2011 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...

2011-04-01

400

Mapping the Galilean satellites of Jupiter with Voyager data.  

USGS Publications Warehouse

The four Galilean satellites of Jupiter are being mapped using image data from the Voyager 1 and 2 spacecraft. The maps are published at several scales and in several versions. Preliminary maps at 1:25,000,000-required for mission planning and preliminary science reports-were compiled within three weeks of data acquisition and have been published. Later maps incorporate Rand Corporation photogrammetric triangulations. - from Authors

Batson, R.M.

1980-01-01

401

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.

402

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

403

The Deep Space Network as an instrument for radio science research  

NASA Technical Reports Server (NTRS)

Radio science experiments use radio links between spacecraft and sensor instrumentation that is implemented in the Deep Space Network. The deep space communication complexes along with the telecommunications subsystem on board the spacecraft constitute the major elements of the radio science instrumentation. Investigators examine small changes in the phase and/or amplitude of the radio signal propagating from a spacecraft to study the atmospheric and ionospheric structure of planets and satellites, planetary gravitational fields, shapes, masses, planetary rings, ephemerides of planets, solar corona, magnetic fields, cometary comae, and such aspects of the theory of general relativity as gravitational waves and gravitational redshift.

Asmar, S. W.; Renzetti, N. A.

1993-01-01

404

SERIES - Satellite Emission Range Inferred Earth Surveying  

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

405

A direct broadcast satellite-audio experiment  

NASA Technical Reports Server (NTRS)

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

Vaisnys, Arvydas; Abbe, Brian; Motamedi, Masoud

1992-01-01

406

Satellite Threat Warning and Attack Reporting  

SciTech Connect

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

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

1997-12-31

407

Corporate social responsibility disclosure and corporate governance in Malaysia  

Microsoft Academic Search

Using 743 Malaysian public listed companies, this study attempts to investigate the impact of corporate governance mechanism on corporate social responsibility (CSR) disclosure level and to examine the difference of CSR disclosure level in government-linked companies and non-government linked companies. Employing multivariate analysis, the study reveals that the presence of larger non-executive directors and a higher involvement of institutional shareholders,

Ying Zhee Lim; Mohammad Talha; Junaini Mohamed; Abdullah Sallehhuddin

2008-01-01

408

Satellite Communications with NRAO Green Bank Antennas  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

409

Radio Surveys: an Overview  

NASA Astrophysics Data System (ADS)

Radio astronomy has provided important surveys that have made possible key (and sometimes serendipitous) discoveries. I will briefly mention some of the past continuum and line (HI) radio surveys as well as new, on-going surveys and surveys planned for the near future. This new generation of large radio surveys is bringing extra challenges in terms of data handling but also great new possibilities thanks to the wider range of data products that they will provide.

Morganti, Raffaella

2015-03-01

410

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.

411

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.

412

Sputnik 1 and the First Satellite Ionospheric Experiment  

NASA Astrophysics Data System (ADS)

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

Sinelnikov, Vyacheslav; Kuznetsov, Vladimir; Alpert, Svetlana

413

Communicating Corporate Social Responsibility - Brand management  

Microsoft Academic Search

Corporate action is subject to more scrutiny than ever. An attempt to legitimize the corporate role is seen in corporate social responsibility as a part of a triple bottom line framework. Corporate principles are communicated in various forms to a wide set of stakeholders. Ideally, what is communicated in terms of principles is also seen in busi- ness practice. In

Cecilia Mark-Herbert; Carolina von Schantz

2007-01-01

414

Corporal Punishment: Legalities, Realities, and Implications.  

ERIC Educational Resources Information Center

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

Hinchey, Patricia H.

2003-01-01

415

27 CFR 40.63 - Corporate documents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Corporate documents. 40.63 Section 40...Manufacturers of Tobacco Products 40.63 Corporate documents. Every corporation...required by 40.62, a true copy of the corporate charter or a certificate...

2010-04-01

416

25 CFR 214.3 - Corporate information.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Corporate information. 214.3 Section 214...MINING, EXCEPT OIL AND GAS 214.3 Corporate information. A corporation shall...showing compliance with local corporation laws in duplicate; a list of all...

2010-04-01

417

Radio Properties of AGN  

NASA Astrophysics Data System (ADS)

To study the radio properties of AGN, we cross-correlate and investigate Veron-Cetty & Veron catalog of QSOs and Active Galaxies (v.13, 2010) with a number of radio catalogs: NVSS, FIRST, GB6, 87GB, SUMSS, WISH, WENSS, and 7C. This catalog contains 168,940 objects with positional accuracy of mostly 1 arcsec, though many positions have larger errors. We use new cross-correlation software based on accuracy of each object independently. In this software we take into account errors for each source and take identifications with errors within 3 sigma. Altogether, we find ~16,000 AGN having radio detection in any of the listed catalogs. Using all data from radio catalogs, we derive a homogeneous sample of radio AGN. The sample allows accomplish several tasks, including study of the distribution of radio sources by activity types, differences in physical properties of radio-loud and radio-quiet AGN, luminosity functions for various types of radio AGN, study of the q parameter by AGN types and its evolution, etc.

Abrahamyan, Hayk V.; Mickaelian, Areg M.

2014-07-01

418

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

419

Satellite to satellite tracking error analysis studies and data processing  

NASA Technical Reports Server (NTRS)

An error analysis was conducted to examine the effects of placing the target satellite in an orbit nearly coplanar with the relay satellite and of data span length on the accuracy with which the satellite states can be recovered. An analysis of error models using actual satellite to satellite tracking data spans is included. Results are tabulated.

Ayres, C. L.; Rosenblatt, G.

1975-01-01

420

75 FR 10439 - Cognitive Radio Technologies and Software Defined Radios  

Federal Register 2010, 2011, 2012, 2013, 2014

...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

421

The European Satellite Users' Association as an education broadcaster on Olympus  

NASA Astrophysics Data System (ADS)

The possibilities opened to educators by the offer of transmission time on the Olympus DBS (Direct Broadcast Satellite) are outlined. The need for proper organization and funding of potential education and training programs is stressed. Eurostep, a cooperative association for educators using satellites is introduced. New markets for tele-education in the fields of medical consultation, vocational and corporate training, and language teaching are described. The need for cooperation between various tele-education programs is stressed.

Groombridge, Brian

1989-05-01

422

Satellites Orbiting Earth  

NSDL National Science Digital Library

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

423

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

424

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

425

The concept of an integrated terrestrial/land mobile satellite system  

NASA Technical Reports Server (NTRS)

Potential satellite markets in the Public Safety (disaster relief, emergency medical and law enforcement) and Common Carrier (mobile radio telephone) service areas are identified. The public mobile telephone segment is then examined to illustrate a methodology for identifying a potential satellite addressable market, including capacity requirements for roughly sizing a satellite. It is postulated that satellites could serve this lower density (mobiles/sq. km), thin-route markets at a competitive cost and thus complement terrestrial systems in the urban and more densely populated areas to provide an integrated nationwide mobile service.

Knouse, G. H.; Castruccio, P. A.

1980-01-01

426

Use of the 30/20 GHz band by multipurpose satellite systems  

NASA Technical Reports Server (NTRS)

The World Administrative Radio Conference (WARC) held in 1992 allocated the bands 19.7-20.2 GHz and 29.5-30.0 GHz to both the Mobile Satellite Service (MSS) and the Fixed Satellite Service (FSS) on a co-primary basis. An economic and flexible solution for the provision of both services is to place both payloads on one spacecraft. Some of the proposed applications of such a hybrid satellite network are described. It also examines the facility for spectrum sharing between the various applications and discusses the impact on coordination. It is concluded that the coordination process would not be more onerous than traditional FSS inter-satellite coordination.

Mcneil, Stephen; Mimis, Vassilios; Sahay, Vishnu; Bowen, Robert

1993-01-01

427

Polar Operational Environmental Satellite  

NSDL National Science Digital Library

The National Oceanic & Atmospheric Administration (NOAA) operates POES, the Polar Operational Environmental Satellite system. Comprised of several components (namely, the Advanced Very High Resolution Radiometer (AVHRR) and the Tiros Operational Vertical Sounder (TOVS)), these satellites make nearly polar orbits daily, providing global coverage of land, ocean, and atmospheric data. The POES Website includes an overview of the satellite system and lists data types such as vegetation index, sea surface temperature charts, volcanic eruption clouds, and much more. For researchers interested in environmental monitoring using satellite-based data, the POES Webpage will serve as a useful reference point.

428

Satellite communication antenna technology  

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

429

Corporate Security and Conflict Outcomes  

E-print Network

of the state as a firm that trades services for rents. I propose that PSFs' influence conflict based on corporate structure, competition and transparency. The empirical analysis examines PSF operations in the U.S.-Iraq conflict. Insurgent attacks...

Tkach, Benjamin K

2013-10-21

430

Campuses Weld the Corporate Link.  

ERIC Educational Resources Information Center

A 1984 survey by American Council on Education, Campus Trends, offers evidence of the extent of academe's involvement in corporate-college collaborative activities. Links including assisting students, supporting research, training employees, and joint programs are discussed. (MLW)

El-Khawas, Elaine

1985-01-01

431

A Case against Corporal Punishment.  

ERIC Educational Resources Information Center

The use of corporal punishment in schools is cited as creating more problems than it solves. Educational and psychological perspectives for the elimination of physical discipline in schools is presented. (JMF)

Ellenberg, F. C.; ominy, James Alton

1978-01-01

432

Corporal punishment in Tanzania's schools  

NASA Astrophysics Data System (ADS)

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

Feinstein, Sheryl; Mwahombela, Lucas

2010-10-01

433

Encycogov: Encyclopedia of Corporate Governance  

NSDL National Science Digital Library

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

434

Application of Field System-FS9 and a PC to Antenna Control Unit interface in Radio Astronomy in Peru  

Microsoft Academic Search

We are in the process to transform a 32m antenna in Peru, used for telecommunications, into a Radio Telescope to perform Radio Astronomy in Peru. The 32m antenna of Peru constructed by NEC was used for telecommunications with communications satellites at 6 GHz for transmission, and 4 GHz for reception. In collaboration of National Institute of Information and Communications Technology

Erick Vidal; Jos Ishitsuka; Yasuhiro Koyama

2006-01-01

435

Tax aspects of collapsible corporations  

E-print Network

TAX ASPECTS OF COLLAPSIBLE CORPORATIONS A Thesis By HERMAN AUGUST LEHMANN Submitted to the Graduate School of the Agricultural and 14 echanical College of Texas in partial fulfillment of the requirements for the degree of MASTER OF BUSINESS... his sincere appreciation for the guidance and assistance rendered by Professor Thomas Vi'. Leland in the preparation of this thesis. TABLE OF CONTENTS Chapter Page I. INTRODUCTION II. PROBLEMS RELATING TO COLLAPSIBLE CORPORATIONS Definition...

Lehmann, Herman August

1960-01-01

436

Managerial Optimism and Corporate Finance  

Microsoft Academic Search

Two dominant features emerge from a simple model of corporate finance with excessively optimistic managers and efficient capital markets.First,optimistic managers believe that capital markets undervalue their firm s risky securities,and may decline positive net present value projects that must be financed externally.Second,optimistic managers overvalue their own corporate projects and may wish to invest in negative net present value projects even

J. B. Heaton

2002-01-01

437

Corporate Yoga and Its Implications  

Microsoft Academic Search

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

Rudra Bhandari; Balkrishna Acharya; V. K. Katiyar

438

Two Essays in Corporate Finance  

E-print Network

TWO ESSAYS IN CORPORATE FINANCE A Dissertation by KERSHEN HUANG Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY May 2011 Major Subject...: Finance TWO ESSAYS IN CORPORATE FINANCE A Dissertation by KERSHEN HUANG Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Co...

Huang, Kershen

2012-07-16

439

Corporate Governance and Equity Prices  

Microsoft Academic Search

Corporate-governance provisions related to takeover defenses and shareholder rights vary substantially across firms. In this paper, we use the incidence of 24 different provisions to build a 'Governance Index' for about 1,500 firms per year, and then we study the relationship between this index and several forward-looking performance measures during the 1990s. We find a striking relationship between corporate governance

Paul A. Gompers; Joy L. Ishii; Andrew Metrick

2001-01-01

440

Unbundling the corporation.  

PubMed

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

Hagel, J; Singer, M

1999-01-01

441

MIMO over Satellite: A Review  

Microsoft Academic Search

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

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

2011-01-01

442

TACTICAL RADIO OPERATIONS August 2009  

E-print Network

FM 6-02.53 TACTICAL RADIO OPERATIONS August 2009 DISTRIBUTION RESTRICTION. Approved for public August 2009 TACTICAL RADIO OPERATIONS Contents Page PREFACE ...........................................................................................................viii Chapter 1 APPLICATIONS FOR TACTICAL RADIO DEPLOYMENT.............................. 1-1 Modularity

US Army Corps of Engineers

443

PARTNeR for Teaching and Learning Radio Astronomy Basics  

NASA Astrophysics Data System (ADS)

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

Vaquerizo, Juan ngel

2010-10-01

444

An overview of satellite-based tele-education activities in Canada  

NASA Astrophysics Data System (ADS)

An overview of the major Canadian tele-educational activities is presented. The need for tele-educational services in a country as large as Canada is outlined. The Access network of the Alberta Educational Communications Corporation is described. The educational radio services in Canada are outlined. The cost effectiveness of tele-education in Canada is evaluated.

Kerr, W. T.; Kawashima, Junichi

1989-05-01

445

Radio Emission from Exoplanets  

E-print Network

We present results from new low frequency observations of two extrasolar planetary systems (Epsilon Eridani and HD128311) taken at 150 MHz with the Giant Metrewave Radio Telescope (GMRT). We do not detect either system, but are able to place tight upper limits on their low frequency radio emission.

Samuel J. George; Ian R. Stevens

2008-04-24

446

Writing for Radio.  

ERIC Educational Resources Information Center

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

Tupper, Marianna S.

1995-01-01

447

Film, Radio, and Television.  

ERIC Educational Resources Information Center

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

Hardesty, Carolyn, Ed.

1990-01-01

448

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

449

A refracting radio telescope  

Microsoft Academic Search

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

Paul Bernhardt; A. V. da Rosa

1977-01-01

450

Smart Radio Spectrum Management for Cognitive Radio  

E-print Network

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

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

2011-01-01

451

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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

452

77 FR 41808 - General Dynamics Itronix Corporation, a Subsidiary of General Dynamics Corporation, Including...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Administration [TA-W-81,448] General Dynamics Itronix Corporation, a Subsidiary of General Dynamics Corporation, Including Remote Workers...to workers and former workers of General Dynamics Itronix Corporation, a subsidiary of...

2012-07-16

453

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

Federal Register 2010, 2011, 2012, 2013, 2014

...TA-W-74,292; TA-W-74,292A] Precision Dynamics Corporation San Fernando, CA; Precision Dynamics Corporation, Also Known as the St. John...2011, applicable to workers of Precision Dynamics Corporation, San Fernando,...

2011-06-15

454

Radio Frequency Identification Technology and the Risk Society: A Preliminary Review and Critique for Justice Studies  

Microsoft Academic Search

Radio Frequency Identification (RFID) technology promises to revolutionize the way in which citizens interact with society, guaranteeing heightened security and increased protection speculatively critiques the soundness of this logic, especially mindful of the risk society thesis. Relevant historical background on RFID is provided, several notable applications in the corporate and governmental sectors are delineated, and the ethical and

Brian Sellers

2009-01-01

455

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

Federal Register 2010, 2011, 2012, 2013, 2014

...The application requests the upgrade of Station KHOV-FM, Wickenburg, from Channel 287C2 to Channel 286C0. See File No. BPH-20080915AFP. To accommodate this proposal, Univision Radio License Corporation filed a petition for rule making...

2012-01-17

456

The First Wave: The Beginnings of Radio in Canadian Distance Education  

ERIC Educational Resources Information Center

This article describes one of the first developments and deployment of radio for distance learning and education in Canada, beginning in the early 1920s. Anticipating a recent initiative of public-private partnerships, the impetus, infrastructure, and initial programs were provided by a large corporation. Description of the system, its purpose,

Buck, George H.

2006-01-01

457

VLBI tracking of GNSS satellites: recent achievements  

NASA Astrophysics Data System (ADS)

While the ITRF (International Terrestrial Reference Frame) is realized by the combination of the various space geodetic techniques, VLBI (Very Long Baseline Interferometry) is the only technique for determining the ICRF (International Celestial Reference Frame) through its observations of extragalactic radio sources. Therefore, small inconsistencies between the two important frames do exist. According to recent comparisons of parameters derived by GNSS (Global Navigation Satellite Systems) and VLBI (e.g. troposphere delays, gradients, UT1-UTC), evidences of discrepancies obtained by the vast amounts of data become obvious. Terrestrial local ties can provide a way to interlink the otherwise independent technique-specific reference frames but only to some degree. It is evident that errors in the determination of the terrestrial ties, e.g. due to the errors when transforming the locally surveyed coordinates into global Cartesian three dimensional coordinates, introduce significant errors in the combined analysis of space geodetic techniques. A new concept for linking the space geodetic techniques might be to introduce celestial ties, e.g. realized by technique co-location on board of satellites. A small satellite carrying a variety of space geodetic techniques is under investigation at GFZ. Such a satellite would provide a new observing platform with its own additional unknowns, such as the orbit or atmospheric drag parameters. A link of the two techniques VLBI and GNSS might be achieved in a more direct way as well: by VLBI tracking of GNSS satellites. Several tests of this type of observation were already successfully carried out. This new kind of hybrid VLBI-GNSS observation would comprise a new direct inter-technique tie without the involvement of surveying methods and would enable improving the consistency of the two space geodetic techniques VLBI and GNSS, in particular of their celestial frames. Recently the radio telescopes Wettzell and Onsala have successfully observed a GNSS satellite for the first time, using also new receiver developments, done at Wettzell. In this contribution we want to develop the motivation for this kind of innovative observation and we will show first results of the test observations.

Liu, Li; Heinkelmann, Robert; Tornatore, Vincenza; Li, Jinling; Mora-Diaz, Julian; Nilsson, Tobias; Karbon, Maria; Raposo-Pulido, Virginia; Soja, Benedikt; Xu, Minghui; Lu, Cuixian; Schuh, Harald

2014-05-01

458

Communication satellite technology trends  

NASA Technical Reports Server (NTRS)

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

Cuccia, Louis

1986-01-01

459

Satellites of spiral galaxies  

NASA Technical Reports Server (NTRS)

We present a survey of satellites around a homogeneous set of late-type spirals with luminosity similar to that of the Milky Way. On average, we find fewer than 1.5 satellites per primary, but we argue that we can treat the survey as an ensemble and so derive the properties of the halo of a 'typical' isolated spiral. The projected density profile of the ensemble falls off approximately as 1/r. Within 50 kpc the azimuthal distribution of satellites shows some evidence for the 'Holmberg effect', an excess near the minor axis of the primary; however, at larger projected distances, the distribution appears isotropic. There is a weak but significant correlation between the size of a satellite and its distance from its primary, as expected if satellites are tidally truncated. Neither Hubble type nor spectral characteristics correlate with apparent separation. The ensemble of satellites appears to be rotating at about 30 km/s in the same direction as the galactic disk. Satellites on prograde orbits tend to be brighter than those on retrograde orbits. The typical velocity difference between a satellite and its primary shows no clear dependence either on apparent separation, or on the rotation speed of the primary. Thus our survey demonstrates that isolated spiral galaxies have massive halos that extend to many optical radii.

Zaritsky, Dennis; Smith, Rodney; Frenk, Carlos; White, Simon D. M.

1993-01-01

460

Satellite Teleconference Final Report.  

ERIC Educational Resources Information Center

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

Elgin Community Coll., IL.

461

ASTER's Satellite Image Gallery  

NSDL National Science Digital Library

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

NASA Jet Propulsion Laboratory

462

Signals from Communications Satellites.  

ERIC Educational Resources Information Center

Discusses the Doppler effect for relative motion between a source of waves and an observer and the orbital dynamics of communications satellites. Presents preliminary calculations of the satellite's altitude and linear velocity using only the concepts of the Doppler shift and the mechanics of motion in a circular path. (JRH)

Thomsen, Volker

1996-01-01

463

Mobile satellite communications  

Microsoft Academic Search

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

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

1994-01-01

464

Efficient Packet Satellite Communications  

Microsoft Academic Search

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

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

1979-01-01

465

Communications technology satellite  

NASA Technical Reports Server (NTRS)

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

1976-01-01

466

Satellites pinpoint tornado clouds  

Microsoft Academic Search

Research into ways to integrate data from satellites and other sources is helping weather forecasters improve their ability to determine quickly where thunderstorm clouds, and perhaps tornados, may occur. Field offices of the National Earth Satellite Service are using new technology to help Weather Service forecasters determine within hours when conditions are right for potentially dangerous storms. J. Purdom, a

Peter M. Bell

1981-01-01

467

Engineer a Satellite  

NSDL National Science Digital Library

In this activity, learners select the scientific instruments for their satellite, calculate the power requirements for all the subsystems, and construct a scale model of their very own Earth observing satellite using building blocks and/or Legos. Includes instructions and worksheets.

468

Prsentation de la radio Badr Benmammar  

E-print Network

combinant anciennes et nouvelles techniques, on parle alors de radio logicielle restreinte (software defined-25Mar2012 #12;2 Plan Radio logicielle (software radio) Radio logicielle restreinte (SDR) Radio cognitive spectre (Spectrum mobility) cel-00680189,version2-25Mar2012 #12;3 Radio logicielle (software radio)Radio

Paris-Sud XI, Universit de

469

Experimental Satellite Quantum Communications  

E-print Network

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

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

2014-06-16

470

Optimization of Satellite Constellation Reconfiguration  

E-print Network

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

471

AB Levitrons and their Applications to Earth's Motionless Satellites  

E-print Network

Author offers the new and distinctly revolutionary method of levitation in artificial magnetic field. It is shown that a very big space station and small satellites may be suspended over the Earth's surface and used as motionless radio-TV translators, telecommunication boosters, absolute geographic position locators, personal and mass entertainment and as planet-observation platforms. Presented here is the theory of big AB artificial magnetic field and levitation in it is generally developed. Computation of three macro-projects: space station at altitude 100 km, TV-communication antenna at height 500 m, and multi-path magnetic highway. Key words: levitation, AB Levitrons, motionless space satellite.

Alexander Bolonkin

2007-08-18

472

Search and rescue satellite-aided tracking system  

NASA Technical Reports Server (NTRS)

The objective of Sarsat is to demonstrate that satellites can greatly facilitate the monitoring, detection, and location of distress incidents alerted by Emergency Locator Transmitters (ELTs) and Emergency Position Indicating Radio Beacons (EPIRBs) carried on commercial, military, and general aviation aircraft and some marine vessels. The detection and location will be accomplished by relaying, via satellite, ELT/EPIRB distress information to ground stations, which will complete the data processing and forward alert and position location data to rescue coordination services. This paper presents a Sarsat system description and a summary of Coast Guard and USAF objectives for the initial demonstration and evaluation tests of Sarsat.

Trudell, B.; Gutwein, J. M.; Vollmers, R.; Wammer, D.

1980-01-01

473

Satellite-aided mobile communications, experiments, applications and prospects  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

474

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

USGS Publications Warehouse

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

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

2003-01-01

475

Detection of X-ray Emission from the Eastern Radio Lobe of PICTOR A  

E-print Network

The XMM-Newton satellite has revealed extended X-ray emission from the eastern radio lobe of the Fanaroff-Riley II Radio Galaxy Pictor A. The X-ray spectrum, accumulated on a region covering about half the entire radio lobe, is well described by both a thermal model and a power law. The X-ray emission could be thermal and produced by circum-galactic gas shocked by the expanding radio lobe or, alternatively, by Inverse Compton (IC) of cosmic microwave background photons by relativistic electrons in the lobe. The latter possibility seems to be supported by the good agreement between the lobe-average synchrotron radio index and the X-ray energy slope. However, if this is the case, the magnetic field, as deduced from the comparison of the IC X-ray and radio fluxes, is more than a factor 2 below the equipartition value estimated in the same X-ray region.

Paola Grandi; Matteo Guainazzi; Laura Maraschi; Raffaella Morganti; Roberto Fusco-Femiano; Mariateresa Fiocchi; Lucia Ballo; Fabrizio Tavecchio

2002-11-25

476

Satellite Services Workshop, Volume 1  

NASA Technical Reports Server (NTRS)

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

1982-01-01

477

Astronaut Ron Parise checks timeline for monitoring Jupiter and its satellites  

NASA Technical Reports Server (NTRS)

Astronaut Ronald A. Parise, STS-67 payload specialist and a senior scientist in the Space Observatories Department of Computer Sciences Corporation (CSC), checks a timeline for monitoring of Jupiter and its satellites. Parise is on the aft flight deck of the Earth-orbiting Space Shuttle Endeavour.

1995-01-01

478

Cognitive Radio An Integrated Agent Architecture for Software Defined Radio  

E-print Network

Cognitive Radio An Integrated Agent Architecture for Software Defined Radio Dissertation Doctor learning and natural language processing technology into software radio. The thesis defines and develops-based control, natural language processing, and machine learning technology into software-defined radio

Maguire Jr., Gerald Q.

479

Multiple Radios for Effective Rendezvous in Cognitive Radio Networks  

E-print Network

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

Chu, Xiaowen

480

Multiple Radios for Fast Rendezvous in Cognitive Radio Networks  

E-print Network

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

Chu, Xiaowen

481

Techniques and Technology Article Optimizing Radio Retention and Minimizing Radio  

E-print Network

Techniques and Technology Article Optimizing Radio Retention and Minimizing Radio Impacts the duration of transmitter attachment and minimizing the impacts of radios on the behavior and demography of the study animal. We tested 4 methods of radio attachment for a breeding population of upland sandpipers

Sandercock, Brett K.

482

Sunsat-2004 satellite and synoptic VLF payload  

NASA Astrophysics Data System (ADS)

Sunsat 2004 is a second satellite from the University of Stellenbosch, with intended suns-synchronous launch in late 2005. The first satellite, Sunsat, was launched in February 1999, and was Africa's first satellite The three-axis stabilised bus will normally point its main solar panel at the sun, but will rotate for imaging. The attitude determination and control system will use coarse sun sensors, magnetometers, rate gyros, and a star mapper, and use reaction wheels and torquer rods for actuation. The payloads include a multispectral pushbroom imager with less than 5m GSD, TV cameras, an Amateur Radio communications payload, and science experiments. The main South African science experiment is a VLF receiver. In the magnetosphere VLF waves play an important role in energy exchange processes with energetic particles. The wave-particle interactions can lead to particle precipitation into the atmosphere or introduce additional energy into particle populations in the magnetosphere. The former is important due to its effect on terrestrial communications while the latter is of interest, as it affects the environment in which satellites operate. A full understanding, of the magnetosphere and phenomena such as the aurora, airglow and particle precipitation, depends on comprehensive wave and particle models together with models of the background plasma density The energetic particle populations and background plasma densities have been extensively modelled using data from a large number of satellite, rocket and ground-based experiments but no comprehensive model of the wave environment exist. The proposed synoptic VLF experiment will start to address this need by locating and tracking the morphology of regions in the magnetosphere where waves are generated. The experiment would consist of a nine channel VLF receiver with a loop antenna. The data would be recorded on board and transmitted to ground stations at appropriate times. A number of additional science payloads are also being evaluated for the mission, and will be reported on in the paper.

Milne, Gw; Hughes, A.; Mostert, S.; Steyn, Wh

483

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.

484

Radio Science in Africa  

NASA Astrophysics Data System (ADS)

Radio science activities covered by URSI (International Radio Science Union) are briefly reviewed. They encompass the knowledge and study of all aspects of electromagnetic fields and waves in a wide frequency range running from micro pulsation frequencies (i.e. from ~1 mHz) to Terahertz. The topics include: electromagnetic measurements and standards, electromagnetic theory and applications, radio-communication systems and signal processing, electronics and Photonics, electromagnetic environment and interference, wave propagation and remote sensing, ionospheric radio and propagation, waves in plasmas, radio astronomy, and electromagnetics in biology and medicine. The main radio science activities conducted by the URSI national Committees of South Africa, Egypt and Nigeria, and by African radio scientists groups gathered in GIRGEA (Groupe International de Recherche en Gophysique Europe Afrique) are reviewed. The emphasis is put on the activities developed in the context of the IHY programme and of the SCINDA network for forecasting ionospheric irregularities that adversely impact communication and navigation systems in the low latitude regions.

Lefeuvre, Francois; Mc Kinnel, Lee-Anne; Chukwuma, Victor; Amory-Mazaudier, Christine

2010-05-01

485

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

486

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

NASA Technical Reports Server (NTRS)

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

Freibaum, Jerry

1990-01-01

487

Upcoming communications satellites  

NASA Astrophysics Data System (ADS)

A new series of international and business communications satellites will be launched by workhorse rocket systems, including updated Delta and Atlas/Centaur rockets, over the next few years. There is, of course, a long-shot option that the space shuttle, as originally conceived, will be used to place the satellites in orbit, but no one is willing to bet right now that the shuttle will be functional and operational in time. Instead, the U.S. will employ updated versions of 15-20-year-old rockets to launch a series of satellites with names like INTELSAT, INSAT, Palapa, and SBS into geosynchronous orbits.INTELSAT V is the first of a new generation of international telecommunications satellites sponsored by the 105-nation International Telecommunications Satellite Organization (INTELSAT), headquartered in Washington, D.C. The satellite, which weighs 1,928 kg at launch, has almost double the communications capability of early satellites in the INTELSAT series. It is positioned in geosynchronous orbit over the Atlantic Ocean so as to provide communications between North America and Europe.

Bell, Peter M.

488

Riding the Radio Waves  

NSDL National Science Digital Library

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 given waveforms. 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. This prepares students to be able to comprehend the functionig of the AM radios they will build during the associated activity.

2014-09-18

489

Overview of commercial satellite communications  

NASA Astrophysics Data System (ADS)

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

Beakley, G. W.

1984-07-01

490

Satellite Tracking Threatened Species  

NSDL National Science Digital Library

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

491

Remote Sensing Using Satellites  

NSDL National Science Digital Library

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

Kathryn Ginger

1998-06-30

492

Skeletal muscle satellite cells  

NASA Technical Reports Server (NTRS)

Evidence now suggests that satellite cells constitute a class of myogenic cells that differ distinctly from other embryonic myoblasts. Satellite cells arise from somites and first appear as a distinct myoblast type well before birth. Satellite cells from different muscles cannot be functionally distinguished from one another and are able to provide nuclei to all fibers without regard to phenotype. Thus, it is difficult to ascribe any significant function to establishing or stabilizing fiber type, even during regeneration. Within a muscle, satellite cells exhibit marked heterogeneity with respect to their proliferative behavior. The satellite cell population on a fiber can be partitioned into those that function as stem cells and those which are readily available for fusion. Recent studies have shown that the cells are not simply spindle shaped, but are very diverse in their morphology and have multiple branches emanating from the poles of the cells. This finding is consistent with other studies indicating that the cells have the capacity for extensive migration within, and perhaps between, muscles. Complexity of cell shape usually reflects increased cytoplasmic volume and organelles including a well developed Golgi, and is usually associated with growing postnatal muscle or muscles undergoing some form of induced adaptive change or repair. The appearance of activated satellite cells suggests some function of the cells in the adaptive process through elaboration and secretion of a product. Significant advances have been made in determining the potential secretion products that satellite cells make. The manner in which satellite cell proliferative and fusion behavior is controlled has also been studied. There seems to be little doubt that cellcell coupling is not how satellite cells and myofibers communicate. Rather satellite cell regulation is through a number of potential growth factors that arise from a number of sources. Critical to the understanding of this form of control is to determine which of the many growth factors that can alter satellite cell behavior in vitro are at work in vivo. Little work has been done to determine what controls are at work after a regeneration response has been initiated. It seems likely that, after injury, growth factors are liberated through proteolytic activity and initiate an activation process whereby cells enter into a proliferative phase. After myofibers are formed, it also seems likely that satellite cell behavior is regulated through diffusible factors arising from the fibers rather than continuous control by circulating factors.(ABSTRACT TRUNCATED AT 400 WORDS).

Schultz, E.; McCormick, K. M.

1994-01-01

493

Satellite Breakup Risk Mitigation  

NASA Technical Reports Server (NTRS)

Many satellite breakups occur as a result of an explosion of stored energy on-board spacecraft or rocket-bodies. These breakups generate a cloud of tens or possibly hundreds of thousands of debris fragments which may pose a transient elevated threat to spaceflight crews and vehicles. Satellite breakups pose a unique threat because the majority of the debris fragments are too small to be tracked from the ground. The United States Human Spaceflight Program is currently implementing a risk mitigation strategy that includes modeling breakup events, establishing action thresholds, and prescribing corresponding mitigation actions in response to satellite breakups.

Leleux, Darrin P.; Smith, Jason T.

2006-01-01

494

Satellite selection criteria  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

495

Hunting for Neutron Star with the Swift Satellite  

Microsoft Academic Search

We are currently pursuing a long-term project to identify new isolated neutron stars from the ROSAT All-Sky Survey Bright Source Catalog using short observations with NASA's Swift satellite. We select our targets via catalog cross-correlation as being likely, on general grounds, to possess a high X-ray to optical\\/IR\\/radio flux ratio. These sources are then observed with Swift on a time-available

Andrew Shevchuk; R. E. Rutledge; D. B. Fox

2007-01-01

496

Modulation/demodulation techniques for satellite communications. Part 1: Background  

NASA Technical Reports Server (NTRS)

Basic characteristics of digital data transmission systems described include the physical communication links, the notion of bandwidth, FCC regulations, and performance measurements such as bit rates, bit error probabilities, throughputs, and delays. The error probability performance and spectral characteristics of various modulation/demodulation techniques commonly used or proposed for use in radio and satellite communication links are summarized. Forward error correction with block or convolutional codes is also discussed along with the important coding parameter, channel cutoff rate.

Omura, J. K.; Simon, M. K.

1981-01-01

497

Requirements for a mobile communications satellite system. Volume 2: Technical report  

NASA Technical Reports Server (NTRS)

Three types of satellite aided mobile communications are considered for users in areas not served by (terrestrial) cellular radio systems. In system 1, mobile units are provided a direct satellite link to a gateway station, which serves as the interface to the terrestrial toll network. In system 2, a terrestrial radio link similar to those in cellular systems connects the mobile unit to a translator station; each translator relays the traffic from mobile units in its vicinity, via satellite, to the regional gateway. It is not feasible for system 2 to provide obiquitous coverage. Therefore, system 3 is introduced, in which the small percentage of users not within range of a translator are provided a direct satellite link as in system 1.

Horstein, M.

1983-01-01

498

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

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

499

ASAP- ARTIFICIAL SATELLITE ANALYSIS PROGRAM  

NASA Technical Reports Server (NTRS)

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

Kwok, J.

1994-01-01

500

NationalRadio Observatory  

E-print Network

exhibits and displays in our exhibit hall where you will discover what radio astronomers are learning about, at least 48 hours before the tour. 15 participants max. No photography. A high-tech tour through telescope

Groppi, Christopher