Science.gov

Sample records for radio satellite corporation

  1. Amateur Radio Satellite Communications.

    ERIC Educational Resources Information Center

    Koch, David P.

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

  2. Radio broadcasting via satellite

    NASA Astrophysics Data System (ADS)

    Helm, Neil R.; Pritchard, Wilbur L.

    1990-10-01

    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.

  3. Direct Broadcast Satellite: Radio Program

    NASA Technical Reports Server (NTRS)

    Hollansworth, James E.

    1992-01-01

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

  4. Oscar satellites, amateur radio in space

    NASA Astrophysics Data System (ADS)

    Henry, J. M.

    The history of amateur radio satellites is reviewed. Attention is given to the Canadian role in the development of the Orbiting Satellite Carrying Amateur Radio OSCAR payload carried aboard the Discoverer 36 satellite. Recent progress in developing new generation amateur radio satellites is addressed with reference to the AMSAT satellite which will retransmit emergency location transmitter signals from aircraft in distress. The position of the ELT is determined by computer processing of doppler information.

  5. A satellite swarm for radio astronomy

    NASA Astrophysics Data System (ADS)

    Dekens, E.; Engelen, S.; Noomen, R.

    2014-09-01

    At present the celestial sky has been mapped in considerable detail for every major wavelength band, except for the ultra-long radiowave band. A space-based interferometer consisting of a swarm of satellites would make it possible to map the celestial sources of 0.1-10 MHz radiation. Such a mission concept called the Orbiting Low Frequency Array (OLFAR) is currently undergoing a feasibility study. This paper presents an analysis of possible operational orbits for the OLFAR satellites. The strategy for OLFAR is to let the satellites drift freely after release into initial orbits. The design of the swarm's reference orbit is primarily motivated by the need for a low radio-noise environment. This results in lunar orbits being main candidates. The design of the initial swarm configuration is primarily motivated by the need for uvw-space coverage. This quantity expresses the variation of lengths and orientations of the satellite relative position vectors over time. Numerical simulations give strong indications that the required uvw-coverage can be met within 1 year of operations with a number of satellites ranging between 25 and 100. A key conclusion is that the orbital behavior of a swarm (characterized by the absence of continuous formation control) is well suited for ultra-long wavelength radio astronomy.

  6. Direct broadcast satellite-radio, receiver development

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  7. Radio occultation based on BeiDou satellite navigation

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  8. Satellite Emission Radio Interferometric Earth Surveying (SERIES). [astrometry

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.

    1980-01-01

    Existing satellite radio emissions of the global positioning system were exploited as a resource for cost effective high accuracy geodetic measurements. System applications were directed toward crustal dynamics and earthquake research.

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

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.

    1979-01-01

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

  10. Wave propagation and earth satellite radio emission studies

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  11. Direct broadcast satellite-radio, space-segment/receiver tradeoffs

    NASA Technical Reports Server (NTRS)

    Golshan, Nasser

    1993-01-01

    The balance between receiver complexity and the required satellite equivalent isotropically radiated power (EIRP) for Direct Broadcast Satellite-Radio (DBS-R) service is addressed. In general the required receiver complexity and cost can be reduced at the expense of higher space-segment cost by allowing a higher satellite EIRP. The tradeoff outcome is sensitive to the total number of anticipated receivers in a given service area, the number of audio programs, and the required audio quality. An understanding of optimum choice of satellite EIRP for DBS-R under various service requirements is a critical issue at this time when International Radio Consultative Committee (CCIR) is soliciting input in preparation for the International Telecommunications Union (ITU) planning conference for the service.

  12. Australis Oscar V - An Australian amateur radio satellite

    NASA Astrophysics Data System (ADS)

    Tonkin, R.; Mace, O.

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

  13. Direct broadcast satellite service by direct broadcast satellite corporation

    NASA Astrophysics Data System (ADS)

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

    1984-03-01

    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.

  14. Planning for Instructional Use of Radio and Computers by Satellite.

    ERIC Educational Resources Information Center

    Suppes, Patrick

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

  15. Investigations of the ionospheric using radio signals from artificial satellites

    NASA Technical Reports Server (NTRS)

    Titheridge, J. E.

    1973-01-01

    The occurrence and characteristics of ionospheric irregularities in medium latitudes and in polar regions were measured using radio signals from artificial satellites. Ionospheric changes during quiet and disturbed conditions were also measured. Electron density, elevation angle, and amplitude and frequency of these high frequency signals were determined as well as the direction of their arrival.

  16. A comparison of type III solar radio burst theories using satellite radio observations and particle measurements.

    NASA Technical Reports Server (NTRS)

    Evans, L. G.; Fainberg, J.; Stone, R. G.

    1971-01-01

    The required electron density to excite a type III solar burst can be predicted from different theories, using the low frequency radio observations of the RAE-1 satellite. Electron flux measurements by satellite in the vicinity of 1 AU then give an independent means of comparing these predicted exciter electron densities to the measured density. On this basis, one theory predicts the electron density in closest agreement with the measured values.

  17. Radio frequency interference from near-earth satellites

    NASA Technical Reports Server (NTRS)

    Levitt, B. K.; Lesh, J. R.

    1977-01-01

    A pessimistic statistical model was developed for predicting the extent of radio frequency interference (RF1). Based on the assumptions underlying the model, DSN S-band operations can expect one RF1 interruption every 4.1 days, with the average incident lasting 24 s. This implies that 52 or more such satellites, with uncorrelated orbital trajectories, will cause in excess of 5 min of RF1 per day at a DSN station.

  18. Fade durations in satellite-path mobile radio propagation

    NASA Technical Reports Server (NTRS)

    Schmier, Robert G.; Bostian, Charles W.

    1986-01-01

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

  19. Satellite observations of transient radio impulses from thunderstorms

    SciTech Connect

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

    1999-06-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  1. Coordination procedure for radio relay and communication satellite services

    NASA Technical Reports Server (NTRS)

    Eckerman, J.

    1973-01-01

    A global rain rate statistic model is used to link microwave propagation statistics to measurable rain statistics in order to develop international telecommunication site criteria for radio relay and communication satellite services that minimize interference between receivers and transmitters. This rain coordination procedure utilizes a rain storm cell size, a statistical description of the rainfall rate within the cell valid for most of the earth's surface, approximations between Raleigh scatter and constancy of precipitation with altitude, and an analytic relation between radar reflectivity and rain rate.

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

    NASA Technical Reports Server (NTRS)

    Hollansworth, James E.

    1993-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Hollansworth, James E.

    1993-01-01

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

  4. Satellites of radio AGN in SDSS: Insights into agn triggering and feedback

    SciTech Connect

    Pace, Cameron; Salim, Samir E-mail: salims@indiana.edu

    2014-04-10

    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 and 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 (17σ 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.

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

    NASA Technical Reports Server (NTRS)

    Hollansworth, James E.

    1993-01-01

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

  6. Terrestrial Myriametric Radio Burst Observed by IMAGE and Geotail Satellites

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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.

  7. Measurements of transionospheric radio propagation parameters using the FORTE satellite

    SciTech Connect

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

    1998-11-01

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

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

    ERIC Educational Resources Information Center

    Pizzi, Skip

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

  9. A radio picture of the earth. [microwave remote sensing from satellites

    NASA Technical Reports Server (NTRS)

    Webster, W. J., Jr.; Wilheit, T. T.; Chang, T. C.; Gloersen, P.; Schmugge, T. J.

    1975-01-01

    A technique called passive microwave remote sensing can be used to obtain a new view of the planet earth by means of radio telescopes carried aboard artificial satellites. An important relationship between the observed radio brightness temperature and the surface conditions provides the basis for the new technique. A radio image is presented of the entire earth on the basis of Nimbus microwave-image data taken January 12-16, 1973.

  10. Design and Validation of High Date Rate Ka-Band Software Defined Radio for Small Satellite

    NASA Technical Reports Server (NTRS)

    Xia, Tian

    2016-01-01

    The Design and Validation of High Date Rate Ka- Band Software Defined Radio for Small Satellite project will develop a novel Ka-band software defined radio (SDR) that is capable of establishing high data rate inter-satellite links with a throughput of 500 megabits per second (Mb/s) and providing millimeter ranging precision. The system will be designed to operate with high performance and reliability that is robust against various interference effects and network anomalies. The Ka-band radio resulting from this work will improve upon state of the art Ka-band radios in terms of dimensional size, mass and power dissipation, which limit their use in small satellites.

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

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

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

  12. Improving capabilities of broadband differential satellite navigation systems via radio occultation technology

    NASA Astrophysics Data System (ADS)

    Myslivtsev, T. O.; Nikiforov, S. V.; Pogoreltsev, A. I.; Savochkin, P. V.; Sakhno, I. V.; Semenov, A. A.; Troitsky, B. V.

    2016-07-01

    The existent satellite system for radio occultation monitoring the Earth's neutral atmosphere and ionosphere (COSMIC) provides data to consumers in the regions with limited possibilities of constructing dense measurement networks (e.g., in the World Ocean area). A forthcoming increase of LEO small spacecrafts and the deployment of new satellite radio navigation systems will result in a pronounced increase in the efficiency of radio occultation method and its space resolution. As a result, the Space-Based Augmentation Systems (SBAS) broadband differential system will become global, or the quality of corrections delivered to single-frequency consumers of individual systems, e.g., the Augmentation and Monitoring System, will be improved. Therefore, the methods for processing and analyzing obtained radio occultation data should be improved. A simple method to reconstruct the electron density profile at radio occultation points, based on the total electron content measurement on the satellite-satellite path and the IRI-type ionospheric model has been proposed. The method needs initial information, it does not require refraction measurements, and it is free of the assumption that the ionosphere is spherically stratified in the occultation region. Verification of the proposed method based on data for 121 radio occultation cases across Europe in May 2013 demonstrated good agreement with the vertical sounding data.

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

    NASA Technical Reports Server (NTRS)

    Dobrozhanskiy, V.; Rybkin, V.

    1980-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    1983-06-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.

    1979-01-01

    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.

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

    ERIC Educational Resources Information Center

    Lee, William E.

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

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

    SciTech Connect

    Stokes, G.M.; Ekstrom, P.A.

    1980-04-01

    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)

  19. Analysis of satellite measurements of terrestrial radio noise

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    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.

  20. Scientific instrumentation of the Radio-Astronomy-Explorer-2 satellite

    NASA Technical Reports Server (NTRS)

    Alexander, J. K.; Kaiser, M. L.; Novaco, J. C.; Grena, F. R.; Weber, R. R.

    1975-01-01

    The instrumentation of the RAE-2 spacecraft is described. The instruments include a pair of long travelling-wave antennas, a 37-m dipole, two radiometers making one frequency scan every 144 sec, and two rapid-sampling total-power burst receivers which cover the range from 0.025 to 13.1 MHz in 32 discrete steps. Effects of terrestrial noise on RAE-1 and RAE-2 observations are discussed, and it is noted that RAE-2 is uniquely capable of observing repeated lunar occultations of strong radio sources at very low frequencies. Some observational programs are briefly noted, including observations of the galactic background distribution, measurements of lunar occultations of solar radio bursts, and searches for more radio sources among the planets, galactic objects, and extragalactic sources.

  1. Radio detection of thunderstorm activity with an earth-orbiting satellite

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Stone, R. G.; Caruso, J. A.

    1975-01-01

    A study was made to determine the feasibility of using artificial earth satellites to monitor thunderstorm activity. The nighttime noise-temperature measurements made with the earth-oriented vee antenna of the Radio Astronomy Explorer (RAE 1) satellite in the frequency range 0.2-9.2 MHz were correlated with reported surface thunderstorm activity. Analysis shows that the minimum nighttime HF noise level (in the absence of surface thunderstorms) at an altitude of 5850 km over the United States is fixed by man-made noise. When thunderstorms are active below the satellite, the noise level is increased by about 6-12 dB. The highest level is associated with the most intense storms. It is concluded that thunderstorm regions can be detected by an orbiting satellite using HF radio techniques, but ionospheric effects must be taken into account.

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

    NASA Technical Reports Server (NTRS)

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

    1971-01-01

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

  3. Scientific instrumentation of the Radio-Astronomy-Explorer-2 satellite

    NASA Technical Reports Server (NTRS)

    Alexander, J. K.; Kaiser, M. L.; Novaco, J. C.; Grena, F. R.; Weber, R. R.

    1974-01-01

    The RAE-2 spacecraft has been collecting radio astronomical measurements in the 25 kHz to 13 MHz frequency range from lunar orbit since June, 1973. A summary is given of the technical aspects of the program including the calibration, instrumentation and operation of the RAE-2 experiments. Performance of the experiments over the first 18 months of the flight is summarized and illustrated. Among the unique features of the RAE-2 is the capability to observe repeated lunar occultations of strong radio sources at very low frequencies.

  4. The impact of the 1979 World Administrative Radio Conference on the fixed-satellite, inter-satellite, and mobile-satellite services

    NASA Astrophysics Data System (ADS)

    Reinhart, E. E.

    1981-08-01

    The impact of the changes in the international radio regulations enacted by the 1979 World Administrative Radio Conference (WARC-79) will be especially strong in the case of the space services, i.e. those services that include radio transmitters and/or receivers located on spacecraft. Attention is given to the six space services that are of greatest interest to commercial point-to-point and mobile telecommunications, including the Fixed-Satellite Service (FSS), the Inter-Satellite Service (ISS), the Mobile-Satellite Service (MSS), and its three components, the Land-Mobile, Maritime-Mobile, and Aeronautical Mobile-Satellite Services. In the case of these six space services, WARC-79 did not make substantial changes either in the technical regulations or in the regulatory procedures applicable over the next few years. However, WARC-79 did adopt major changes in the frequency allocations for the FSS, ISS, and MSS, and did agree to hold a future World Administrative Radio Conference that could drastically change the way in which countries obtain frequencies and orbital positions for their space services.

  5. Simultaneous ground- and satellite-based observation of MF/HF auroral radio emissions

    NASA Astrophysics Data System (ADS)

    Sato, Yuka; Kumamoto, Atsushi; Katoh, Yuto; Shinbori, Atsuki; Kadokura, Akira; Ogawa, Yasunobu

    2016-05-01

    We report on the first simultaneous measurements of medium-high frequency (MF/HF) auroral radio emissions (above 1 MHz) by ground- and satellite-based instruments. Observational data were obtained by the ground-based passive receivers in Iceland and Svalbard, and by the Plasma Waves and Sounder experiment (PWS) mounted on the Akebono satellite. We observed two simultaneous appearance events, during which the frequencies of the auroral roar and MF bursts detected at ground level were different from those of the terrestrial hectometric radiation (THR) observed by the Akebono satellite passing over the ground-based stations. This frequency difference confirms that auroral roar and THR are generated at different altitudes across the F peak. We did not observe any simultaneous observations that indicated an identical generation region of auroral roar and THR. In most cases, MF/HF auroral radio emissions were observed only by the ground-based detector, or by the satellite-based detector, even when the satellite was passing directly over the ground-based stations. A higher detection rate was observed from space than from ground level. This can primarily be explained in terms of the idea that the Akebono satellite can detect THR emissions coming from a wider region, and because a considerable portion of auroral radio emissions generated in the bottomside F region are masked by ionospheric absorption and screening in the D/E regions associated with ionization which results from auroral electrons and solar UV radiation.

  6. Concept of distributed corporative wireless vehicle voice networks based on radio-over-fiber technique

    NASA Astrophysics Data System (ADS)

    Bourdine, Anton V.; Bukashkin, Sergey A.; Buzov, Alexander V.; Kubanov, Victor P.; Praporshchikov, Denis E.; Tyazhev, Anatoly I.

    2016-03-01

    This work is concerned on description of the concept of corporative wireless vehicle voice networks based on Radioover- Fiber (RoF) technology, which is integration of wireless and fiber optic networks. The concept of RoF means to transport data over optical fibers by modulating lightwave with radio frequency signal or at the intermediate frequency/baseband that provides to take advantage of the low loss and large bandwidth of an optical fiber together with immunity to electromagnetic influence, flexibility and transparence. A brief overview of key RoF techniques as well as comparative analysis and ability of its application for wireless vehicle voice network realization is presented.

  7. Terrestrial Myriametric Radio Burst Observed by IMAGE and Geotail Satellites

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Mulhall, B. D. L.

    1977-01-01

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

  9. Direct broadcast satellite-radio: Portable and mobile reception trade-offs

    NASA Technical Reports Server (NTRS)

    Golshan, Nasser

    1991-01-01

    There has been considerable international effort in the areas of system studies, system development, and regulatory work for a Direct Broadcast Satellite Radio (DBS-R). An important milestone will be the 1992 World Radio Administrative Conference (WARC 1992) consideration of frequency allocation in the 500 - 3000 MHz range for such a service. There is an interagency agreement between Voice of America and the National Aeronautics and Space Administration for a coordinated program in DBS-R. This program includes seven tasks: systems tradeoff studies, propagation measurements, satellite experiment and demonstration, receiver development, market studies, regulatory studies, and WARC preparations. The findings of ongoing work under the first task, systems tradeoff studies, are discussed. Topics covered include digital bit rate and audio quality, propagation considerations and link margin estimates for portable reception, link margin estimates for mobile reception, coverage, and satellite size and cost estimates for a regional DBS-R coverage example.

  10. On-glass automotive diversity antenna and LNA design for S-band satellite digital radio

    NASA Astrophysics Data System (ADS)

    Yeğin, Korkut

    2015-11-01

    Selection combining diversity system with antennas mounted on windshield and backlite of a vehicle is proposed for satellite digital audio radio applications. Standalone exterior mount antennas on metallic vehicles perform well for satellite digital audio radio applications, but for composite body vehicles or interior mount antennas, antenna performance becomes a real issue. Proposed on-glass two-antenna diversity is one solution for such applications. The antenna correlation is calculated using the S-parameters of the antennas and found to be very low due to many wavelengths separation between the antennas. Design of low noise amplifier, which has sub 1 dB noise figure and good P1dB due to strong cellular signals, is also detailed. A diversity receiver is described and ride tests are performed to assess the performance of the diversity system in real-time, under weak satellite signal environment which is regarded as the most challenging reception condition.

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

    NASA Technical Reports Server (NTRS)

    Fainberg, J.; Stone, R. G.

    1973-01-01

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

  12. 47 CFR 25.214 - Technical requirements for space stations in the Satellite Digital Audio Radio Service and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... the Satellite Digital Audio Radio Service and associated terrestrial repeaters. 25.214 Section 25.214 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.214 Technical requirements for space stations in the Satellite Digital Audio...

  13. 47 CFR 25.214 - Technical requirements for space stations in the satellite digital audio radio service and...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the satellite digital audio radio service and associated terrestrial repeaters. 25.214 Section 25.214 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.214 Technical requirements for space stations in the satellite digital audio...

  14. 47 CFR 25.214 - Technical requirements for space stations in the satellite digital audio radio service and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... the satellite digital audio radio service and associated terrestrial repeaters. 25.214 Section 25.214 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.214 Technical requirements for space stations in the satellite digital audio...

  15. 47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Licensing provisions for the 2.3 GHz satellite... (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25.144 Licensing provisions for the 2.3 GHz satellite digital audio radio service. (a)...

  16. 47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Licensing provisions for the 2.3 GHz satellite... (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25.144 Licensing provisions for the 2.3 GHz satellite digital audio radio service. (a)...

  17. 47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Licensing provisions for the 2.3 GHz satellite... (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25.144 Licensing provisions for the 2.3 GHz satellite digital audio radio service. (a)...

  18. 47 CFR 25.214 - Technical requirements for space stations in the satellite digital audio radio service and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... the satellite digital audio radio service and associated terrestrial repeaters. 25.214 Section 25.214 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.214 Technical requirements for space stations in the satellite digital audio...

  19. 47 CFR 25.214 - Technical requirements for space stations in the Satellite Digital Audio Radio Service and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... the Satellite Digital Audio Radio Service and associated terrestrial repeaters. 25.214 Section 25.214 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.214 Technical requirements for space stations in the Satellite Digital Audio...

  20. Radio sky mapping from satellites at very low frequencies

    NASA Technical Reports Server (NTRS)

    Storey, L. R. O.

    1991-01-01

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

  1. Networked Operations of Hybrid Radio Optical Communications Satellites

    NASA Technical Reports Server (NTRS)

    Hylton, Alan; Raible, Daniel

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1996-05-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  4. Propagation measurements for satellite radio reception inside buildings

    NASA Technical Reports Server (NTRS)

    Vogel, Wolfhard J.; Torrence, Geoffrey W.

    1993-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Alvarez, H.

    1971-01-01

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

  6. Pulsed radio frequency interference effects on data communications via satellite transponder

    NASA Technical Reports Server (NTRS)

    Weinberg, A.; Hong, Y.

    1979-01-01

    Power-limited communication links may be susceptible to significant degradation if intentional or unintentional pulsed high level radio frequency interference (RFI) is present. Pulsed RFI is, in fact, of current interest to NASA in studies relating to its Tracking and Data Relay Satellite System (TDRSS). The present paper examines the impact of pulsed RFI on the error probability performance of a power-limited satellite communication link: the assumed modulation scheme is PN coded binary PSK. The composite effects of thermal noise, pulsed CW and pulsed Gaussian noise are analyzed, where RFI arrivals are assumed to follow Poisson statistics. Under the assumption that the satellite repeater is ideal and that integrate and dump filtering is employed at the ground receiver, an exact error probability expression and associated approximations are derived. Computed results are generated using an arbitrarily specified RFI model.

  7. Solar Paddle Antenna on Pico-Satellite for Amateur Radio Communication

    NASA Astrophysics Data System (ADS)

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

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

  8. 47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Licensing provisions for the 2.3 GHz satellite digital audio radio service. 25.144 Section 25.144 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25.144 Licensing provisions for the 2.3...

  9. The Italian Radio Occultation experiment on-board the Indian OCEANSAT-2 satellite

    NASA Astrophysics Data System (ADS)

    Perona, G.; Rosa Team

    During the June 2007 the Indian satellite OCEANSAT-2 will be launched The Italian Space Agency ASI signed a Memorandum of Understandings with the Indian Space Research Organization ISRO in which it is agreed to put on-board the OCEANSAT-2 satellite the Italian GNSS receiver devoted to Radio Occultation ROSA - Radio Occultation Sounder of the Atmosphere In the framework of this mission this instrument can only be able to observe rising occultations the Radio Occultation antenna will be mounted on the aft-velocity direction collecting data both in Open-Loop and in Close-Loop modes These data will be downloaded to the Indian and the Italian receiving stations where they will be processed by the ROSA ground segment completely developed by Italian universities and research centres In particular this ground segment will be implemented at a first level in an integrated computing infrastructure installed in Matera and mirrored at Hyderbad in India and at a second level on a distributed software and hardware infrastructure This second infrastructure will perform the rapid and precise Orbit Determination and Prediction the bending and impact parameters profiles extraction the ionospheric correction and the stratospheric initialization the refractivity pressure temperature and humidity profile retrieval the value added services for meteorology climate and space weather applications by computing units of each research centre or university connected through a Web-based GRID computing infrastructure After a description of these two

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    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).

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  12. Sounding of HF heating-induced artificial ionospheric disturbances by navigational satellite radio transmissions

    NASA Astrophysics Data System (ADS)

    Kunitsyn, V. E.; Andreeva, E. S.; Frolov, V. L.; Komrakov, G. P.; Nazarenko, M. O.; Padokhin, A. M.

    2012-01-01

    During experiments carried out in 2009-2011 the midlatitude ionosphere was modified by powerful HF pulses from the Sura heating facility located near Nizhny Novgorod (Russia) and operated by the Radio Physical Research Institute. GPS/GLONASS and Parus/Tsikada satellite radio transmissions responding to the heating-induced disturbances in electron density were analyzed. The variations in the total electron content (TEC), which are proportional to the reduced phase of navigational signals, were studied for various schemes of radiation of the heating wave. The variations in TEC (their amplitudes and temporal behavior) caused by HF heating are identified in several examples. The TEC spectra contain frequency components corresponding to the modulation periods of the heating wave. For the first time, the spatial structure of the wave disturbances generated in the ionosphere by high-power radio waves radiated by the Sura heating facility with a square wave modulation of the effective radiated power at a frequency lower than or of the order of the Brunt-Vaisala frequency of the neutral atmosphere is imaged using the method of low-orbital radio tomography and GPS/GLONASS data.

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

    NASA Technical Reports Server (NTRS)

    Stevenson, S.; Provencher, C.

    1984-01-01

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

  14. Video data link provides television pictures in near real time via tactical radio and satellite channels

    NASA Astrophysics Data System (ADS)

    Hartman, Richard V.

    1987-02-01

    Advances in sophisticated algorithms and parallel VLSI processing have resulted in the capability for near real-time transmission of television pictures (optical and FLIR) via existing telephone lines, tactical radios, and military satellite channels. Concepts have been field-demonstrated with production-ready engineering development models using transform compression techniques. Preliminary design has been completed for packaging an existing command post version into a 20-pound enclosure for use on jeeps, backpacks, RPVs, helicopters, and reconnaissance aircraft. The system will also have a built-in error correction code unit, allowing operation via communciations media exhibiting a bit error rate of 0.01 or better.

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

    NASA Technical Reports Server (NTRS)

    Murray, C. W., Jr.

    1977-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Moody, Daniela I.; Smith, David A.

    2014-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Moody, Daniela I.; Smith, David A.

    2014-01-01

    Ongoing research at Los Alamos National Laboratory studies the Earth's radio frequency (RF) background utilizing satellite-based RF observations of terrestrial lightning. Such impulsive events 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.

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Mate, Bruce; Mesecar, Roderick; Lagerquist, Barbara

    2007-02-01

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

  20. The Hitachi and Takahagi 32 m radio telescopes: Upgrade of the antennas from satellite communication to radio astronomy

    NASA Astrophysics Data System (ADS)

    Yonekura, Yoshinori; Saito, Yu; Sugiyama, Koichiro; Soon, Kang Lou; Momose, Munetake; Yokosawa, Masayoshi; Ogawa, Hideo; Kimura, Kimihiro; Abe, Yasuhiro; Nishimura, Atsushi; Hasegawa, Yutaka; Fujisawa, Kenta; Tomoaki, Oyama; Kono, Yusuke; Miyamoto, Yusuke; Sawada-Satoh, Satoko; Hideyuki, Kobayashi; Kawaguchi, Noriyuki; Honma, Mareki; Shibata, Katsunori M.; Sato, Katsuhisa; Ueno, Yuji; Jike, Takaaki; Tamura, Yoshiaki; Hirota, Tomoya; Miyazaki, Atsushi; Niinuma, Kotaro; Sorai, Kazuo; Takaba, Hiroshi; Hachisuka, Kazuya; Kondo, Tetsuro; Sekido, Mamoru; Murata, Yasuhiro; Nakai, Naomasa; Omodaka, Toshihiro

    2016-05-01

    The Hitachi and Takahagi 32 m radio telescopes (former satellite communication antennas) were so upgraded as to work at 6, 8, and 22 GHz. We developed the receiver systems, IF systems, back-end systems (including samplers and recorders), and reference systems. We measured the performance of the antennas. The system temperature including the atmosphere toward the zenith, T_sys^{ast }, is measured to be ˜30-40 K for 6 GHz and ˜25-35 K for 8 GHz. T_sys^{ast } for 22 GHz is measured to be ˜40-100 K in winter and ˜150-500 K in summer seasons, respectively. The aperture efficiency is 55%-75% for Hitachi at 6 GHz and 8 GHz, and 55%-65% for Takahagi at 8 GHz. The beam sizes at 6 GHz and 8 GHz are ˜4{^'.}6 and ˜3{^'.}8, respectively. The side-lobe level is less than 3%-4% at 6 and 8 GHz. Pointing accuracy was measured to be better than ˜0{^'.}3 for Hitachi and ˜0{^'.}6 for Takahagi. We succeeded in VLBI observations in 2010 August, indicating good performance of the antenna. We started single-dish monitoring observations of 6.7 GHz methanol maser sources in 2012 December, and found several new sources showing short-term periodic variation of the flux density.

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

    PubMed

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

    1986-07-01

    alone the mass of the Uranian system is GM(sys) = 5,794,547- 60 cubic kilometers per square second; from a combination of radio and optical navigation data the mass of Uranus alone is GM(u) = 5,793,939+/- 60 cubic kilometers per square second. From all available Voyager data, induding imaging radii, the mean uncompressed density of the five major satellites is 1.40+/- 0.07 grams per cubic centimeter; this value is consistent with a solar mix of material and apparently rules out a cometary origin of the satellites. PMID:17812893

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

    NASA Astrophysics Data System (ADS)

    Parrot, M.; Berthelier, J. J.; Blecki, J.; Brochot, J. Y.; Hobara, Y.; Lagoutte, D.; Lebreton, J. P.; Němec, F.; Onishi, T.; Pinçon, J. L.; Píša, D.; Santolík, O.; Sauvaud, J. A.; Slominska, E.

    2015-05-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Weinberg, A.

    1984-01-01

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

  4. 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

    2013-07-23

    ....263(b) and 25.263(c) published at 78 FR 9605, February 11, 2013, are effective July 23, 2013. FOR...- 130, published at 78 FR 9605, February 11, 2013. The OMB Control Number is 3060-1153. The Commission... COMMISSION 47 CFR Part 25 Establishment of Rules and Policies for the Digital Audio Radio Satellite...

  5. 47 CFR 25.144 - Licensing provisions for the 2.3 GHz satellite digital audio radio service.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... digital audio radio system, setting forth all pertinent technical and operational aspects of the system... receiver that will permit end users to access all licensed satellite DARS systems that are operational or... implementation milestone as specified in the system authorization, and on the basis of the...

  6. 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

    2011-09-19

    ...In this document, the Commission announces that the Office of Management and Budget (OMB) has approved, for a period of three years, the information collection requirements contained in the Satellite Digital Audio Radio Service (SDARS) Second Report and Order. The information collection requirements were approved on July 5, 2011 by...

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

    NASA Astrophysics Data System (ADS)

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

    2006-10-01

    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 flash, indicating that this radio signature is produced by continuing lightning current. Second, in two events with strong postreturn stroke extremely low frequency (ELF) magnetic pulses, the optical emissions demonstrate that there are no observable intensifications of low-altitude optical emissions associated with those pulses. If they were produced by a lightning process, such as an M-component, the connection between optical emissions and current seen in the return stroke and the continuing current suggests they should be visible. However, as has been observed previously, the bright, high-altitude optical emissions associated with the sprite are simultaneous with the ELF pulse. This is strong evidence that these ELF pulses originate in high-altitude electric current in the sprite itself and are not produced by a low-altitude lightning process.

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

    NASA Technical Reports Server (NTRS)

    Laymon, Charles; Srinivasan, Karthik; Limaye, Ashutosh

    2011-01-01

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

  9. Real-time HF Radio Absorption Maps Incorporating Riometer and Satellite Measurements

    NASA Astrophysics Data System (ADS)

    Rogers, Neil; Honary, Farideh; Warrington, Mike; Stocker, Alan; Danskin, Donald

    2016-04-01

    A real-time model of HF radio propagation conditions is being developed as a service for aircraft communications at high latitudes. An essential component of this is a real-time map of the absorption of HF (3-30 MHz) radio signals in the D-region ionosphere. Empirical, climatological Polar Cap Absorption (PCA) models in common usage cannot account for day-to-day variations in ionospheric composition and are inaccurate during the large changes in recombination rate at twilight. However, parameters of such models may be optimised using an age-weighted regression to absorption measurements from riometers in Canada and Scandinavia. Such parameters include the day- and night-time sensitivity to proton flux as measured on a geostationary satellite (GOES). Modelling the twilight transition as a linear or Gauss error function over a range of solar-zenith angles (χl < χ < χu) is found to provide greater accuracy than 'Earth shadow' methods (as applied in the Sodankylä Ionospheric Chemistry (SIC) model, for example) due to a more gradual ionospheric response for χ < 90° . The fitted χl parameter is found to be most variable, with smaller values (as low as 60°) post-sunrise compared with pre-sunset. Correlation coefficients of model parameters between riometers are presented and these provide a means of appropriately weighting individual riometer contributions in an assimilative PCA model. At times outside of PCA events, the probability of absorption in the auroral zones is related to the energetic electron flux inside the precipitation loss cone, as measured on the polar-orbiting POES satellites. This varies with magnetic local time, magnetic latitude and geomagnetic activity, and its relation to the real-time solar wind - magnetospheric coupling function [Newell et al., 2007] will be presented. Reference: Newell, P. T., T. Sotirelis, K. Liou, C.-I. Meng, and F. J. Rich (2007), A nearly universal solar wind-magnetosphere coupling function inferred from 10

  10. Comparison between GPS radio occultation electron densities and in situ satellite observations

    NASA Astrophysics Data System (ADS)

    Pedatella, N. M.; Yue, X.; Schreiner, W. S.

    2015-06-01

    Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Global Positioning System (GPS) radio occultation (RO) electron densities are compared with collocated in situ observations from the CHAllenging Minisatellite Payload (CHAMP) and Communications/Navigation Outage Forecasting System (C/NOFS) satellites. The comparison is restricted to observations occurring within 2° latitude and longitude and 15 min local time. The in situ observations occur at altitudes of ˜300-800 km, and the results of the present study represent the first global comparison of COSMIC electron densities at altitudes ranging from near the F region peak to the topside ionosphere. The correlation coefficient between the COSMIC and in situ observations is greater than 0.90, indicating an overall good agreement between GPS RO electron densities and CHAMP and C/NOFS satellite observations. Furthermore, when averaged over all latitudes and local times, we find a near-zero mean bias and root-mean-square difference of typically less than ±30% between the COSMIC electron densities and collocated in situ observations. The overall good agreement demonstrates that the COSMIC GPS RO observations provide an accurate measure of electron density in the topside ionosphere. The results also reveal a systematic structure to the error in the equatorial and low-latitude daytime ionosphere. This structure is related to the equatorial ionization anomaly and is consistent with the error introduced by the Abel inversion spherical symmetry assumption used to retrieve the COSMIC electron density profiles. The present study thus provides direct observational evidence of the Abel inversion error on GPS RO electron densities.

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    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

    The development of quantitative models that describe physical processes from the solar corona to the Earth’s 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.

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

    NASA Technical Reports Server (NTRS)

    Sood, Des R.

    1991-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Arai, Kohei

    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.

  15. Direct Broadcast Satellites: An Interview with Hartford Gunn.

    ERIC Educational Resources Information Center

    Library Hi Tech, 1984

    1984-01-01

    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…

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  18. An experimental investigation of the power spectrum of phase modulation induced on a satellite radio signal by the ionosphere

    NASA Technical Reports Server (NTRS)

    Moser, D. T.

    1972-01-01

    The power spectrum of phase modulation imposed upon satellite radio signals by the inhomogeneous F-region of the ionosphere (100 - 500 km) was studied. Tapes of the S-66 Beacon B Satellite recorded during the period 1964 - 1966 were processed to yield or record the frequency of modulation induced on the signals by ionospheric dispersion. This modulation is produced from the sweeping across the receiving station as the satellite transits of the two dimensional spatial phase pattern are produced on the ground. From this a power spectrum of structure sizes comprising the diffracting mechanism was determined using digital techniques. Fresnel oscillations were observed and analyzed along with some comments on the statistical stationarity of the shape of the power spectrum observed.

  19. Satellites

    SciTech Connect

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

    1986-01-01

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

  20. Hybrid system of communication and radio determination using two geostationary satellites

    NASA Technical Reports Server (NTRS)

    Ohmori, Shingo; Matsumoto, Yasushi; Morikawa, Eihisa; Wakao, Masayoshi

    1990-01-01

    A new hybrid satellite system which can provide both communications and positioning services in one system using two geostationary satellites is discussed. The distinctive feature is that location information can be provided by transmitting and receiving ranging signals over the same channel as communications through two geostationary satellites.

  1. The RadioSat (sm) network

    NASA Technical Reports Server (NTRS)

    Noreen, Gary K.

    1991-01-01

    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.

  2. Video Data Link Provides Television Pictures In Near Real Time Via Tactical Radio And Satellite Channels

    NASA Astrophysics Data System (ADS)

    Hartman, Richard V.

    1987-02-01

    Advances in sophisticated algorithms and parallel VLSI processing have resulted in the capability for near real-time transmission of television pictures (optical and FLIR) via existing telephone lines, tactical radios, and military satellite channels. Concepts have been field demonstrated with production ready engineering development models using transform compression techniques. Preliminary design has been completed for packaging an existing command post version into a 20 pound 1/2 ATR enclosure for use on jeeps, backpacks, RPVs, helicopters, and reconnaissance aircraft. The system will also have a built-in error correction code 2 (ECC) unit, allowing operation via communicatons media exhibiting a bit error rate of 1 X 10-or better. In the past several years, two nearly simultaneous developments show promise of allowing the breakthrough needed to give the operational commander a practical means for obtaining pictorial information from the battlefield. And, he can obtain this information in near real time using available communications channels--his long sought after pictorial force multiplier: • High speed digital integrated circuitry that is affordable, and • An understanding of the practical applications of information theory. High speed digital integrated circuits allow an analog television picture to be nearly instantaneously converted to a digital serial bit stream so that it can be transmitted as rapidly or slowly as desired, depending on the available transmission channel bandwidth. Perhaps more importantly, digitizing the picture allows it to be stored and processed in a number of ways. Most typically, processing is performed to reduce the amount of data that must be transmitted, while still maintaining maximum picture quality. Reducing the amount of data that must be transmitted is important since it allows a narrower bandwidth in the scarce frequency spectrum to be used for transmission of pictures, or if only a narrow bandwidth is available, it

  3. 1.6 GHz distress radio call system (DRCS) via geostationary satellite (Inmarsat-E) - Results of the preoperational demonstration

    NASA Astrophysics Data System (ADS)

    Goebel, Walter

    1990-10-01

    The paper discusses features and operations of the spaceborne Emergency Position Indicating Radio Beacons (EPIRBs) system for distress alerting, which is expected to be used on every ship by August 1, 1993. Two types of EPIRBs that were developed to date are described: the floatable EPIRB, used by vessels over 300 GRT (convention ships subjected to the IMO rules) and the hand-held EPIRB used by smaller vessels such as fishing boats or yachts. The transmitted message formats of both are fully compatible. The distress alerts are presently transmitted through the polar orbiting satellite service at 406 MHz. However, the 36th Inmarsat Council in 1990 passed a decision to the effect that the Inmarsat geostationary satellite shall provide service at 1.6 GHz.

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

    NASA Astrophysics Data System (ADS)

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

    2004-05-01

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

  5. 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)

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

    2011-07-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    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.

  7. Engineering parameter determination from the radio astronomy explorer /RAE I/ satellite attitude data

    NASA Technical Reports Server (NTRS)

    Lawlor, E. A.; Davis, R. M.; Blanchard, D. L.

    1974-01-01

    An RAE-I satellite description is given, taking into account a dynamics experiment and the attitude sensing system. A computer program for analyzing flexible spacecraft attitude motions is considered, giving attention to the geometry of rod deformation. The characteristics of observed attitude data are discussed along with an analysis of the main boom root angle, the bending rigidity, and the damper plane angle.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-06-01

    We analyze the ionospheric effect on the phase and amplitude of radio occultation (RO) signal. The introduced theoretical model predicts a correlation between the phase acceleration and intensity variations of RO signal and opens a way to locate layered structures in the propagation medium, in particular, in trans-ionospheric satellite-to-satellite links. For considered CHAllenging Minisatellite Payload (CHAMP) RO events, the locations of the inclined plasma layers in the lower ionosphere are estimated, and the electron density distribution is retrieved. By analysis of the CHAMP RO data, we reveal the dependence of the intensity variations of RO signal on sharp changes in the DST index and on the local time. Maps of the seasonal, geographical, and temporal distributions of the CHAMP RO events with amplitude scintillations, having high S4 index values, and observed during the years 2001-2004 indicate dependence on solar activity. As follows from this analysis, the GPS signals in the trans-ionospheric links can be used for investigating the location and parameters of inclined plasma layers and monitoring the influence of solar activity on the ionosphere with global coverage.

  10. A novel method for measuring the polarization angle of satellite radio waves

    NASA Technical Reports Server (NTRS)

    Antoniadis, D. A.

    1974-01-01

    One of the most important parameters for the study of the physics of the ionosphere is the columnar electron content. This can be obtained indirectly by measuring the Faraday rotation of signals emitted from satellites. Many different types of polarimeters have been developed for this purpose. Efforts to develop a new type of polarimeter, suitable for extensive network operation, led to a novel technique for measuring the polarization angle.

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

    SciTech Connect

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

    1994-09-01

    An interferometer described in the Boston, 1992, meeting of the Beacon Satellite Symposium has been in full operation for over a year now. It consists of four autonomous stations; three are in a triangle 70 km on a side and one is in the center. The stations receive the VHF beacons from two geosynchronous satellites, GOES-2 and ATS-3. The phases of the beacons are tracked at each station by referring them to an extremely stable rubidium oscillator. The studies of the two satellites are virtually separate experiments. The received phase of the beacon is retarded by the increased Total-Electron-Content of the dense regions of waves in the ionosphere. By comparing the phase history at four spatially separated stations, the authors can determine the two-dimensional propagation vector of the waves. This array is optimal for wavelengths of 70--300 km (periods of 300--3,000 seconds). Since the measurement is of the phase of the signal rather than the difference between the O-mode and X-mode phases, and since the beacons are in the VHF rather than in the L-band of GPS beacons, the array is very sensitive. It has a noise level of 10{sup 13} electrons/m{sup 2}, or 10{sup {minus}4} of the normal daytime TEC. This has been verified by operating two stations in the same location, so that they saw the same ionosphere. The first interesting results from a year`s study is that the authors do not see the same TID`s when looking at the two satellites. One conclusion they draw is that they do not see evidence of ionospheric winds.

  12. Recent Results From the Whistler- and Z-mode Radio Sounding From the IMAGE Satellite

    NASA Astrophysics Data System (ADS)

    Sonwalkar, V. S.; Reddy, A.; Mayank, K.; Hazra, S.; Carpenter, D. L.

    2014-12-01

    Whistler mode radio sounding method [Sonwalkar et al., JGR, 2011] was applied to two case studies: (1) daytime and nighttime cases of whistler mode echoes observed on IMAGE inside the plasmasphere (L<4, altitude <5000 km), and (2) cases of whistler mode echoes observed during geomagnetic storm activity. Preliminary results indicate: (i) O+/H+ and O+/ (H+ + He+) transition heights at nighttime are a few hundred kilometers lower than that at daytime. (ii) Electron and ion densities found from whistler mode sounding are consistent with those from the past in situ and radio sounding measurements, but differ from those predicted by IRI-2012 and GCPM. (iii) Electron and ion densities undergo temporal changes as a function of geomagnetic storm activity, and each species has different recovery period. (iv) Major, moderate, and minor storms affect Ne, H+, and O+ densities in a similar manner, but affect He+ density differently-the minor storm did not affect it. By comparing the electron and ion densities measured by whistler mode radio sounding with those predicted by physics based ionospheric models (e.g. SAMI 2) it may be possible to understand how thermospheric winds influence the evolution of the ionospheric electron and ion densities during geomagnetic storms. The application of Sonwalkar et al. [2011] method to nonducted and ducted fast Z mode echoes observed on IMAGE has led to the measurement of field aligned electron density and duct width and enhancement factor from ~1000 km up to the equator. In two cases, ducts with widths of ~0.05-0.1 L and density depletions of ~5-10 % accounted for the observed properties of ducted Z mode echoes. The measurements of both electron density and ducts are consistent with past measurements. The results from the whistler and Z mode sounding will lead to new empirical models of field aligned electron and ion densities and a statistical characterization of ducts in the magnetosphere.

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

    NASA Astrophysics Data System (ADS)

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

    1996-12-01

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

  14. The role of the magnetosphere in satellite and radio-star scintillation

    NASA Technical Reports Server (NTRS)

    Booker, H. G.

    1975-01-01

    A theory is developed to account for the scintillation phenomenon observed in equatorial regions when using communications satellites in the SHF band. The same theory is also used qualitatively to explain strong scintillations in the VHF band. Instead of confining irregularities to a narrow interval of height in the F-region and assuming that they are strong, the alternative hypothesis is used that the irregularities are weak but extend from the F-region upwards into the magnetosphere. It is suggested that the irregularities are field-aligned and extend at least up to an L-shell of 1.3 and possibly up to 2 or more.

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

    USGS Publications Warehouse

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

    2005-01-01

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

  16. Future communications satellite applications

    NASA Technical Reports Server (NTRS)

    Bagwell, James W.

    1992-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Freeman, J. W.; Simons, S.

    1981-01-01

    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.

  18. An implementation of Software Defined Radios for federated aerospace networks: Informing satellite implementations using an inter-balloon communications experiment

    NASA Astrophysics Data System (ADS)

    Akhtyamov, Rustam; Cruz, Ignasi Lluch i.; Matevosyan, Hripsime; Knoll, Dominik; Pica, Udrivolf; Lisi, Marco; Golkar, Alessandro

    2016-06-01

    Novel space mission concepts such as Federated Satellite Systems promise to enhance sustainability, robustness, and reliability of current missions by means of in-orbit sharing of space assets. This new paradigm requires the utilization of several technologies in order to confer flexibility and re-configurability to communications systems among heterogeneous spacecrafts. This paper illustrates the results of the experimental demonstration of the value proposition of federated satellites through two stratospheric balloons interoperating with a tracking ground station through Commercial Off-The-Shelf Software Defined Radios (SDRs). The paper reports telemetry analysis and characterizes the communications network that was realized in-flight. Furthermore, it provides details on an in-flight anomaly experienced by one of the balloons, which was recovered through the use of the federated technology that has been developed. The anomaly experienced led to the early loss of the directional link from the ground station to the affected stratospheric balloon node after 15 min in flight. Nevertheless, thanks to the federated approach among the systems, the ground station was still able to retrieve the balloon's data in real time through the network system, for which the other balloon operated as a federated relay for 45 min in flight, uninterrupted. In other words, the federated approach to the system allowed triplicating the useful lifetime of the defective system, which would have not been possible to realize otherwise. Such anomaly coincidentally demonstrated the value of the federated approach to space systems design. The paper paves the way for future tests on space assets.

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

    NASA Astrophysics Data System (ADS)

    Kirillovich, Ivan; Gubenko, Vladimir; Pavelyev, Alexander

    Internal gravity waves (IGWs) modulate the structure and circulation of the Earth’s 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

  20. 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)

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

    2010-12-01

    The problem of detecting nature's most energetic particles—cosmic rays and neutrinos—is 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.

  1. User applications unique to mobile satellites

    NASA Astrophysics Data System (ADS)

    Castiel, David

    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.

  2. User applications unique to mobile satellites

    NASA Technical Reports Server (NTRS)

    Castiel, David

    1990-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

    1993-01-01

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

  4. Radio data transmission for SCADA

    SciTech Connect

    Frasier, W.E. )

    1989-09-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  6. Concept and Analysis of a Satellite for Space-Based Radio Detection of Ultra-High Energy Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Romero-Wolf, Andrew; Gorham, P.; Booth, J.; Chen, P.; Duren, R. M.; Liewer, K.; Nam, J.; Saltzberg, D.; Schoorlemmer, H.; Wissel, S.; Zairfian, P.

    2014-01-01

    We present a concept for on-orbit radio detection of ultra-high energy cosmic rays (UHECRs) that has the potential to provide collection rates of ~100 events per year for energies above 10^20 eV. The synoptic wideband orbiting radio detector (SWORD) mission's high event statistics at these energies combined with the pointing capabilities of a space-borne antenna array could enable charged particle astronomy. The detector concept is based on ANITA's successful detection UHECRs where the geosynchrotron radio signal produced by the extended air shower is reflected off the Earth's surface and detected in flight.

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

    NASA Technical Reports Server (NTRS)

    1990-01-01

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

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

    NASA Technical Reports Server (NTRS)

    1990-01-01

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

  9. Comparison of topside electron density measured by Radio Occultation (RO) of FORMOSAT-3/COSMIC satellites and Digisondes on a global scale with IRI

    NASA Astrophysics Data System (ADS)

    Das, Tanmay; Haralambous, Haris

    2016-07-01

    This paper represents a comparison of the topside electron density of the F2-layer measured by FORMOSAT-3/COSMIC satellites in terms of GPS radio occultation technique and digisondes as manually scaled ionograms being provided by DIDBase (Digital Ionogram Database) with IRI. This study encompasses data from more than 40 locations for an extended period from January 2007 to December 2015. It utilises a subset of around 1000 very well matched (in terms of bottomside) FORMOSAT-3/COSMIC - Digisonde electron density profile pairs to compare the corresponding topside electron density profiles with IRI. The selection criteria for the electron density profile pairs, apart from coincidence of COSMIC and Digisonde electron density in the bottomside, is a collocation distance of less than 2.5o in terms of latitude and longtitude and 15 min maximum time difference in measuring NmF2 with the two techniques.

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

    USGS Publications Warehouse

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

    2013-01-01

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

  11. Anomalies in VLF radio signals related to the seismicity during November-December 2004: A comparison of ground and satellite results

    NASA Astrophysics Data System (ADS)

    Biagi, P. F.; Castellana, L.; Maggipinto, T.; Maggipinto, G.; Minafra, A.; Ermini, A.; Molchanov, O.; Rozhnoi, A.; Solovieva, M.; Hayakawa, M.

    A previous study of the intensity of VLF signals radiated by two ground transmitters located in Germany ( f = 16.6 kHz) and France ( f = 18.3 kHz) and received on board the French satellite DEMETER, revealed an intensity drop in the time interval November 23-December 12, 2004, probably connected with the occurrence of earthquakes ( M = 5.4-5.5) in central Europe. From 2002 a receiver has been operating at Bari (Italy) and the intensity and the phase of the VLF/LF radio signals radiated by GB ( f = 16 kHz, United Kingdom), FR ( f = 20.9 kHz, France), GE ( f = 23.4 kHz, Germany), IC ( f = 37.5 kHz, Island) and IT ( f = 54 kHz, Sicily, Italy) are being monitored with a 5 s sampling rate. In order to confirm the results obtained by the satellite measurements, both the intensity and the phase data collected by the Bari receiver from October 2004 to January 2005 have been analysed. As concerns the intensity, drops of the GB, FR, GE and IC signals were revealed before the middle of November and a drop of the IT signal appeared before December 10. The geomagnetic activity gives satisfactory justification of the November drops; on the contrary no correspondence stood up with the drop in December and seismic effects can be claimed. As concerns the phase data, at first the wavelet analysis was applied and clear anomalies were revealed on the FR and IC signals at the end of November. These anomalies appear as precursors with respect to all the mentioned seismic activity. Then, the standard deviation of the phase data sets was investigated and a clear drop was revealed on the GE signal on 23-24 November, that is just before one of the previous large earthquakes. So, not only an agreement of the ground results with those obtained by the satellite appears, but also a more precise definition of the connection between the radio anomalies and the earthquakes stands up using the ground data.

  12. Low Earth orbit communications satellite

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    A current thrust in satellite communication systems considers a low-Earth orbiting constellations of satellites for continuous global coverage. Conceptual design studies have been done at the time of this design project by LORAL Aerospace Corporation under the program name GLOBALSTAR and by Motorola under their IRIDIUM program. This design project concentrates on the spacecraft design of the GLOBALSTAR low-Earth orbiting communication system. Overview information on the program was gained through the Federal Communications Commission licensing request. The GLOBALSTAR system consists of 48 operational satellites positioned in a Walker Delta pattern providing global coverage and redundancy. The operational orbit is 1389 km (750 nmi) altitude with eight planes of six satellites each. The orbital planes are spaced 45 deg., and the spacecraft are separated by 60 deg. within the plane. A Delta 2 launch vehicle is used to carry six spacecraft for orbit establishment. Once in orbit, the spacecraft will utilize code-division multiple access (spread spectrum modulation) for digital relay, voice, and radio determination satellite services (RDSS) yielding position determination with accuracy up to 200 meters.

  13. Theory of intense radio waves in an underdense ionosphere: application to solar power satellite transmissions. Final report

    SciTech Connect

    Goldman, M V

    1980-11-01

    The instabilities in the F-region plasma are investigated that can be created by the passage of a solar power satellite beam (2.45 Ghz frequency, at a power flux of 23 mW/cm/sup 2/) at frequencies much higher than the cut-off plasma frequency of the ionosphere. The threshold geometry and frequency and intensity scaling laws are calculated for the thermal self-focusing instability, and its saturation level is estimated. The possibility is considered of scaled experiments at HF power to detect the thermal self-focusing instability for an underdense ionosphere. Other experimental possibilities are discussed in terms of the scaling laws. (LEW)

  14. The effect of circular satellite orbits assumption on inverting earth's stmospheric parameters byGPS radio occultation

    NASA Astrophysics Data System (ADS)

    Jiang, H.

    2001-08-01

    The analytic expressions for refracting angle in GPS radio occultation is presented Taking the refracting angle under circular orbit assumptions as a priori value iterative processing is employed to derive refracting angle series devoid of circular orbit assumptions. Further, differenced atmospheric parameters are calculated based on an inverse method, taking into account the two different cases cases (inclusive of and exclusive of circular orbit assumptions).It has demonstrated that effect of circular orbit assumptions will bring about up to one milli-bar bias in pressure and up to one Kelvin bias in temperature. On one hand, this result supports those researchers who are engaged in qualitative error sourced analyses and are liable to employ circular orbit assumptions; on the other hand, it warns it necessary to keep in mind forsaking the circular orbit assumptions when demanding accuracy is the atmospheric parameters.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  16. Variability of Atmospheric Boundary Layer height over the tropical oceans - A study using atmospheric refractivity profiles from multi campaign in-situ and satellite radio occultation data.

    NASA Astrophysics Data System (ADS)

    Santosh, M.

    2016-07-01

    Atmospheric Boundary Layer (ABL) over the tropical oceans controls and regulates the influx of water vapour into the free atmosphere due to evaporation. The availability of in situ data for determining the ABL characteristics over tropical oceans are limited to different ship based campaigns and hence restricted in spatial and temporal coverage. For ABL studies the Radio Occultation (RO) based satellite data over tropical oceans have good temporal and spatial coverage but limited in temporal and spatial resolution. Atmospheric refractivity profiles are extensively used in many studies to determine the ABL height from both platforms. The present study attempts to use the advantages in both in-situ and satellite (RO) based data to quantify the variability in the ABL height over the tropical oceans. All studies done so far to identify the ABL height from RO derived refractivity profiles rely extensively on the detection of the minimum refractivity gradient (MRG) below ~6 km along with additional threshold criteria. This leads to an over estimation of ABL heights especially in presence of strong subsidence inversion caused by local/ mesoscale/ synoptic scale processes where the MRG lies significantly above the ABL. The present study attempts to quantify this over estimation using atmospheric refractivity profiles derived from thermo-dynamical parameters from radiosonde ascents over the tropical ocean, suggests an improved method of ABL detection and quantifies the variability so deduced. Over 1000 radiosonde ascents from four ship cruises conducted during DYNAMO 2011 field campaign over the tropical Indian Ocean are used for the purpose. ABL heights determined from radiosonde data using traditional methods (using virtual potential temperature and specific humidity) are compared with those identified from simulated atmospheric refractivity profiles from same data (using prevalent methods for RO) to quantify the over estimation. A new method of ABL detection from

  17. [Theme Issue: Communications Satellites.

    ERIC Educational Resources Information Center

    Howkins, John, Ed.

    1976-01-01

    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…

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  19. Radio Galaxies.

    ERIC Educational Resources Information Center

    Downes, Ann

    1986-01-01

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

  20. Satellite myths

    NASA Astrophysics Data System (ADS)

    Easton, Roger L.; Hall, David

    2008-01-01

    Richard Corfield's article “Sputnik's legacy” (October 2007 pp23-27) states that the satellite on board the US Vanguard rocket, which exploded during launch on 6 December 1957 two months after Sputnik's successful take-off, was “a hastily put together contraption of wires and circuitry designed only to send a radio signal back to Earth”. In fact, the Vanguard satellite was developed over a period of several years and put together carefully using the best techniques and equipment available at the time - such as transistors from Bell Laboratories/Western Electric. The satellite contained not one but two transmitters, in which the crystal-controlled oscillators had been designed to measure both the temperature of the satellite shell and of the internal package.

  1. Domestic Communication Satellites

    ERIC Educational Resources Information Center

    Horowitz, Andrew

    1974-01-01

    A discussion of the Federal Communications Commission's new policy on domestic satellites in light of our 1) military and economic history; 2) corporate interests; 3) citizen surveillance; and 4) media control. (HB)

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    The Radio Occultation and Heavy Precipitation (ROHP) experiment, to be conducted aboard the Spanish PAZ satellite, consists of a radio occultation (RO) mission provided with dual-polarization capabilities. The research with polarimetric RO data has the goal of assessing the capabilities and limitations of this technique to infer profiles of heavy precipitation. The technique aims to provide vertical profiles of precipitation simultaneously to the vertical profiles of thermodynamic parameters (standard RO products) perfectly collocated both in space and time. If successful, the polarimetric RO will represent the first technique able to provide these complementary information on precipitation. This is a relevant input for studies on heavy and violent rainfall events, which being poorly represented by the current-generation of Numerical Weather Prediction and General Circulation Models appear to be difficult to forecast on all time-scales. The Low Earth Orbiter hosting this experiment, to be launched in 2013, will orbit at 500 km altitude in a near-Polar orbit. The Radio Occulation payload includes a RO GNSS receiver and a dual polarization (H/V) limb oriented antenna to capture the signals of setting GNSS transmitters. NOAA and UCAR participate in the ground-segment of the radiometric experiment to enable near-real time dissemination of the level-1 standard RO products. The space-based GNSS RO technique scans the atmosphere vertically at fine resolution (close to 300 meter in the troposphere) by precisely measure the delay between a GNSS transmitter and a GNSS receiver aboard a Low Earth Orbiter, when the former is setting below or rising above the Earth limb. The standard, thermodynamical, products are extracted from the excess delay induced by the atmosphere at different layers. This presentation will not focus on this well-established application, but a novel concept using polarimetry to also retrieve rain information. The precipitation-measurement principle is

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

    ERIC Educational Resources Information Center

    Pizzi, Skip

    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…

  4. Satellite broadcasting

    NASA Astrophysics Data System (ADS)

    Gregory, D.; Rainger, P.; Harvey, R. V.; Jennings, A.

    Questions related to direct broadcasting satellites are addressed with attention given to celestial mechanics, synchronous orbits, propagation, international plans, domestic installation, related laws and system costs. The role of the World Administrative Planning Conference (WARC) organization is discussed and contrasted with that of the regional administrative radio conference. Topics related to the field of law include coverage and overspill, regulation and control, copyrights and international organizations. Alternative ways of estimating direct broadcasting system costs are presented with consideration given to satellite costs as a function of mass, launch costs and system costs as a function of power.

  5. Satellite orbit predictor

    NASA Technical Reports Server (NTRS)

    Friedman, Morton l.; Garrett, James, Major

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

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

    ERIC Educational Resources Information Center

    Duff, D. A.

    1981-01-01

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

  7. 33 CFR 401.63 - Radio procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Radio procedures. 401.63 Section 401.63 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Radio Communications § 401.63 Radio procedures....

  8. 33 CFR 401.63 - Radio procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Radio procedures. 401.63 Section 401.63 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Radio Communications § 401.63 Radio procedures....

  9. 33 CFR 401.63 - Radio procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Radio procedures. 401.63 Section 401.63 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Radio Communications § 401.63 Radio procedures....

  10. 33 CFR 401.63 - Radio procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Radio procedures. 401.63 Section 401.63 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Radio Communications § 401.63 Radio procedures....

  11. 33 CFR 401.63 - Radio procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Radio procedures. 401.63 Section 401.63 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Radio Communications § 401.63 Radio procedures....

  12. A Question of Interference: FM Radio's Early Struggle for Survival 1934-1945.

    ERIC Educational Resources Information Center

    Zenaty, Jayne W.

    This paper explores FM radio's struggle for survival in the 1940s, focusing primarily on the impact of Federal Communications Commission (FCC) decision making and on the influence and activities of the well-established radio corporations, primarily the Radio Corporation of America (RCA). It describes the invention of FM radio by Edwin H. Armstrong…

  13. Fundamentals of satellite navigation

    NASA Astrophysics Data System (ADS)

    Stiller, A. H.

    The basic operating principles and capabilities of conventional and satellite-based navigation systems for air, sea, and land vehicles are reviewed and illustrated with diagrams. Consideration is given to autonomous onboard systems; systems based on visible or radio beacons; the Transit, Cicada, Navstar-GPS, and Glonass satellite systems; the physical laws and parameters of satellite motion; the definition of time in satellite systems; and the content of the demodulated GPS data signal. The GPS and Glonass data format frames are presented graphically, and tables listing the GPS and Glonass satellites, their technical characteristics, and the (past or scheduled) launch dates are provided.

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

    ERIC Educational Resources Information Center

    Casey-Stahmer, Anna

    1979-01-01

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

  15. Live Satellite Communications... An Exciting Teaching Aid

    ERIC Educational Resources Information Center

    Journal of Aerospace Education, 1976

    1976-01-01

    Describes ways that orbiting satellites carrying amateur radios can be used in the classroom at various grade levels to supplement physics, mathematics, electronics, and social science curricula. (MLH)

  16. Telemetry Data Collection from Oscar Satellite

    NASA Technical Reports Server (NTRS)

    Haddock, Paul C.; Horan, Stephen

    1998-01-01

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

  17. Civil satellite navigation and location systems

    NASA Astrophysics Data System (ADS)

    Blanchard, W. F.

    1989-05-01

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

  18. 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)

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

    2012-01-01

    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

  19. Analysis, prediction and control of radio frequency interference with respect to DSN

    NASA Technical Reports Server (NTRS)

    Degroot, N. F.

    1982-01-01

    Susceptibility modeling, prediction of radio frequency interference from satellites, operational radio frequency interference control, and international regulations are considered. The existing satellite interference prediction program DSIP2 is emphasized. A summary status evaluation and recommendations for future work are given.

  20. Methods of satellite oceanography

    NASA Technical Reports Server (NTRS)

    Stewart, R. H.

    1985-01-01

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

  1. Satellite networks for education

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  2. 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)

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

    1990-01-01

    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).

  3. 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

    SciTech Connect

    James, H.G.; Benson, R.F.; Fainberg, J.; Stone, R.G. NASA, Goddard Space Flight Center, Greenbelt, MD )

    1990-06-01

    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). 21 refs.

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

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  5. Satellite (IRLS) tracking of elk

    NASA Technical Reports Server (NTRS)

    Buechner, H. K.

    1972-01-01

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

  6. Galileo radio science investigations

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    Galileo radio-propagation experiments are based on measurements of absolute and differential propagation time delay, differential phase delay, Doppler shift, signal strength, and polarization. These measurements can be used to study: the atmospheric and ionospheric structure, constituents, and dynamics of Jupiter; the magnetic field of Jupiter; the diameter of Io, its ionospheric structure, and the distribution of plasma in the Io torus; the diameters of the other Galilean satellites, certain properties of their surfaces, and possibly their atmospheres and ionospheres; and the plasma dynamics and magnetic field of the solar corona. The spacecraft system provides linear rather than circular polarization on the S-band downlink signal, the capability to receive X-band uplink signals, and a differential downlink ranging mode. A highly-stable, dual-frequency, spacecraft radio system is developed that is suitable for simultaneous measurements of all the parameters normally attributed to radio waves.

  7. Mobile satellite service communications tests using a NASA satellite

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  8. Ganymede: A New Radio Source

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1994-07-01

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

  10. Educational Radio.

    ERIC Educational Resources Information Center

    Arafeh, Sousan

    1999-01-01

    Examines the effectiveness of the radio in education and the crucial role of the radio in distance education in first half of the 20th century; dramatic social changes in the 1960s that led to a review of educational institutions and of educational media; and the radio today as a neglected but inexpensive medium of communication that should be…

  11. TDRSS Augmentation System for Satellites

    NASA Technical Reports Server (NTRS)

    Heckler, Gregory W.; Gramling, Cheryl; Valdez, Jennifer; Baldwin, Philip

    2016-01-01

    In 2015, NASA Goddard Space Flight Center (GSFC) reinvigorated the development of the TDRSS Augmentation Service for Satellites (TASS). TASS is a global, space-based, communications and navigation service for users of Global Navigation Satellite Systems(GNSS) and the Tracking and Data Relay Satellite System (TDRSS). TASS leverages the existing TDRSS to provide an S-band beacon radio navigation and messaging source to users at orbital altitudes 1400 km and below.

  12. Satellite networks for education.

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  13. Firefighters' Radios

    NASA Technical Reports Server (NTRS)

    1976-01-01

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

  14. 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)

    1979-01-01

    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.

  15. Corporal Punishment.

    ERIC Educational Resources Information Center

    Ball, Joan

    1989-01-01

    The National PTA opposes the use of corporal punishment in schools. Several states and foreign countries have banned this form of discipline, and studies show it to be ineffective. Alternative methods of controlling student behaviors are suggested. (IAH)

  16. Regulation of Wire and Radio Communication.

    ERIC Educational Resources Information Center

    Federal Communications Commission, Washington, DC.

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

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

    NASA Astrophysics Data System (ADS)

    Humbert, Angelika; Steinhage, Daniel

    2010-05-01

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

  18. Radio wave.

    PubMed

    Elkin, V

    1992-01-01

    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

  19. Radio receivers

    NASA Astrophysics Data System (ADS)

    Bankov, V. N.; Barulin, L. G.; Zhodzishskii, M. I.; Malyshev, I. V.; Petrusinskii, V. V.

    The book is concerned with the design of microelectronic radio receivers and their components based on semiconductor and hybrid integrated circuits. Topics discussed include the hierarchical structure of radio receivers, the synthesis of structural schemes, the design of the principal functional units, and the design of radio receiver systems with digital signal processing. The discussion also covers the integrated circuits of multifunctional amplifiers, analog multipliers, charge-transfer devices, frequency filters, piezoelectronic devices, and microwave amplifiers, filters, and mixers.

  20. TV via satellite from AT&T

    NASA Astrophysics Data System (ADS)

    Kiely, J.

    1982-04-01

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

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

    NASA Technical Reports Server (NTRS)

    Paulikas, G. A.

    1974-01-01

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

  2. Weather, land satellite sale

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

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

  3. Educational Radio.

    ERIC Educational Resources Information Center

    Federal Communications Commission, Washington, DC.

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

  4. Radio astronomy

    NASA Technical Reports Server (NTRS)

    Wolken, P. R.; Schaffer, R. D.; Gorenstein, M. V.

    1981-01-01

    The activities of the Deep Space Network in support of Radio Astronomy Operations during April and May 1981 are reported. Work in progres in support of an experiment selected for use of the DSN by the Radio Astronomy Experiment Selection Panel, Twin Quasi-Stellar Object VLBI, is reported.

  5. Radio astronomy

    NASA Technical Reports Server (NTRS)

    Taylor, R. M.; Manchester, R. N.

    1980-01-01

    The activities of the Deep Space Network in support of radio and radar astronomy operations during July and August 1980 are reported. A brief update on the OSS-sponsored planetary radio astronomy experiment is provided. Also included are two updates, one each from Spain and Australia on current host country activities.

  6. Radio astronomy

    NASA Technical Reports Server (NTRS)

    Shaffer, R. D.; Wolken, P. R.; Gulkis, S.

    1981-01-01

    The activities of the Deep Space Network in support of radio astronomy operations during the first quarter of 1981 are reported. Results of the use of a low noise maser are presented, as well as updates in DSN support of experiments sanctioned by the Radio Astronomy Experiment Selection Panel.

  7. Radio Astronomy

    NASA Technical Reports Server (NTRS)

    Shaffer, R. D.; Wolken, P. R.; Niell, A. E.

    1981-01-01

    The activities of the DSN in support of Radio and Radar Astronomy Operations during September through December 1980 are described. Emphasis is on a report of an experiment selected for use of the DSN by the radio Astronomy Experiment Selection Panel: that of VLBI observations of the energetic galactic object SS-433.

  8. Radio stars.

    PubMed

    Hjellming, R M; Wade, C M

    1971-09-17

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

  9. College Radio.

    ERIC Educational Resources Information Center

    Sauls, Samuel J.

    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…

  10. Corporal punishment.

    PubMed

    Zolotor, Adam J

    2014-10-01

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

  11. Satellite oceanography - The instruments

    NASA Technical Reports Server (NTRS)

    Stewart, R. H.

    1981-01-01

    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.

  12. Satellite Communication.

    ERIC Educational Resources Information Center

    Technology Teacher, 1985

    1985-01-01

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

  13. Corporate Raiding.

    ERIC Educational Resources Information Center

    Evelyn, Jamilah

    1999-01-01

    The search for college faculty members of color has led one organization to recruit doctoral candidates from the business world. Funded with $6 million in corporate sponsorship, the project subsidizes business professionals' doctoral study, helps run doctoral student associations, and brings students and business school officials to annual…

  14. Pupil projects involving satellites

    NASA Astrophysics Data System (ADS)

    Perry, G.

    1984-05-01

    The techniques used by pupils at Kettering School, UK, to monitor the USSR space program (using NASA-supplied NORAD radar data and radio transmissions from the spacecraft) are reviewed, and some results are summarized. The main methods used by the pupils include plotting plane spacings, determining orbital periods, and monitoring transmissions from meteorological and navigation satellites and cosmonaut voice communications. The programs covered are briefly characterized, and a glossary of terms is provided.

  15. Compact private hubs for corporate VSAT networks

    NASA Astrophysics Data System (ADS)

    Shimabukuro, Tom M.; Subbarayan, Ravi

    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.

  16. Radio Pulsars

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  17. Radio Astronomy

    NASA Technical Reports Server (NTRS)

    Wolken, P. R.; Shaffer, R. D.

    1983-01-01

    Deep Space Network (DSN) 26- and 64-meter antenna stations were utilized in support of Radio Astronomy Experiment Selection Panel experiments. Within a time span of 10 days, in May 1983 (267.75 hours total), nine RAES experiments were supported. Most of these experiments involved multifacility interferometry using Mark 3 data recording terminals and as many as six non-DSN observatories. Investigations of black holes, quasars, galaxies, and radio sources are discussed.

  18. 47 CFR 73.4091 - Direct broadcast satellites.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Direct broadcast satellites. 73.4091 Section 73.4091 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4091 Direct broadcast satellites. (a)...

  19. 47 CFR 73.4091 - Direct broadcast satellites.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Direct broadcast satellites. 73.4091 Section 73.4091 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4091 Direct broadcast satellites. (a)...

  20. 47 CFR 73.4091 - Direct broadcast satellites.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Direct broadcast satellites. 73.4091 Section 73.4091 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4091 Direct broadcast satellites. (a)...

  1. 47 CFR 73.4091 - Direct broadcast satellites.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Direct broadcast satellites. 73.4091 Section 73.4091 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4091 Direct broadcast satellites. (a)...

  2. 47 CFR 73.4091 - Direct broadcast satellites.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Direct broadcast satellites. 73.4091 Section 73.4091 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.4091 Direct broadcast satellites. (a)...

  3. Mobile satellite regulation in the United States

    NASA Technical Reports Server (NTRS)

    Levin, Lon C.; Sonnenfeldt, Walter H.

    1990-01-01

    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.

  4. Satellite sound broadcast research aspect in CRL

    NASA Technical Reports Server (NTRS)

    Hase, Yoshihiro; Kondo, Kimio; Ohmori, Shingo

    1990-01-01

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

  5. Mobile radio interferometric geodetic systems

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.; Niell, A. E.; Ong, K. M.; Resch, G. M.; Morabito, D. D.; Claflin, E. S.; Lockhart, T. G.

    1978-01-01

    Operation of the Astronomical Radio Interferometric Earth Surveying (ARIES) in a proof of concept mode is discussed. Accuracy demonstrations over a short baseline, a 180 km baseline, and a 380 km baseline are documented. Use of ARIES in the Sea Slope Experiment of the National Geodetic Survey to study the apparent differences between oceanographic and geodetic leveling determinations of the sea surface along the Pacific Coast is described. Intergration of the NAVSTAR Global Positioning System and a concept called SERIES (Satellite Emission Radio Interferometric Earth Surveying) is briefly reviewed.

  6. Radio Relays Improve Wireless Products

    NASA Technical Reports Server (NTRS)

    2009-01-01

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

  7. Application of mesh network radios to UGS

    NASA Astrophysics Data System (ADS)

    Calcutt, Wade; Jones, Barry; Roeder, Brent

    2008-04-01

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

  8. Public Radio Programming Content by Category, Fiscal Year 1982.

    ERIC Educational Resources Information Center

    Mendel, Robin; And Others

    Part of a series of statistical surveys on public broadcasting based on data supplied by public television and Corporation for Public Broadcasting qualified public radio stations, this report provides details of public radio program content for fiscal year 1982. The chapters include information on the following: (1) definitions and categories; (2)…

  9. Satellite communications

    NASA Astrophysics Data System (ADS)

    Saha, M. K.

    1982-11-01

    The paper describes the basic principles and the historial development of satellite communications. Various satellite systems for global communications are discused and compared. Some typical operational communication satellite systems summary including geostationary systems are presented. Considerations leading to the system design including the link design for various multiple access techniques and the future trends in satellite communications systems are also discussed.

  10. Satellite communications

    NASA Astrophysics Data System (ADS)

    Rubin, Philip A.

    A review of the economic and technological status of the satellite communications industry is presented. The history of satellite communications is outlined, focusing on the launching of Syncom III in 1963. The basic operation of communication satellites is explained. The differences between C and Ku frequency bands are examined. Economic issues related to satellite communications are discussed in detail.

  11. The Direct Satellite Connection: Definitions and Prospects.

    ERIC Educational Resources Information Center

    Wigand, Rolf T.

    1980-01-01

    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)

  12. Use of communications. [satellite communication

    NASA Technical Reports Server (NTRS)

    1975-01-01

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

  13. Radio astronomy

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  14. Gentris corporation.

    PubMed

    Crean, Jennifer

    2002-01-01

    Gentris Corporation is engaged in the development and rapid commercialization of innovative proprietary clinical pharmacogenomic products and services. The company provides global pharmaceutical research organizations with turn-key pharmacogenomic solutions to improve the efficiency and predictability of drug development. The ultimate benefit to these organizations is to shorten drug development cycles, improve new drug approval rates and allow marginal drugs to advance towards final approval. In the near future, the company will develop specialized, high quality, reliable diagnostic products, which will provide physicians and their patients with access to pharmacogenomic testing, as personalized medicine becomes the new standard of medical practice. PMID:11966411

  15. Financial Statistics of CPB-Qualified Public Radio Stations: Fiscal Year 1970. Advance Edition.

    ERIC Educational Resources Information Center

    Pedone, Ronald J.; And Others

    Based on information provided by public television and radio station licensees to the Corporation for Public Broadcasting (CPB), this report presents financial data for fiscal year 1970 for CPB-qualified public radio stations in the United States. A brief discussion of the 91 CPB-qualified public radio stations is provided first, along with an…

  16. A study of satellite emergency locator systems

    NASA Technical Reports Server (NTRS)

    1977-01-01

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

  17. Engineering calculations for communications satellite systems planning

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  18. Voyager-Jupiter radio science data papers

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    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.

  20. Corporate Jet

    NASA Technical Reports Server (NTRS)

    1991-01-01

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

  1. Analysis and Modeling of Jovian Radio Emissions Observed by Galileo

    NASA Technical Reports Server (NTRS)

    Menietti, J. D.

    2003-01-01

    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.

  2. Layered sensing with radio (LSWR)

    NASA Astrophysics Data System (ADS)

    Mitra, Atindra K.

    2010-04-01

    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).

  3. The Radio JOVE Project - Shoestring Radio Astronomy

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  4. Space Telecommunications Radio System STRS Cognitive Radio

    NASA Technical Reports Server (NTRS)

    Briones, Janette C.; Handler, Louis M.

    2013-01-01

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

  5. Radio Seeing Monitor Interferometer

    NASA Astrophysics Data System (ADS)

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

    2002-10-01

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

  6. LDEF Satellite Radiation Analyses

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

    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.

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

    ERIC Educational Resources Information Center

    Fletcher, James E.

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

  8. Ultra-stable radio frequency dissemination in free space.

    PubMed

    Miao, J; Wang, B; Gao, C; Bai, Y; Zhu, X; Wang, L J

    2013-10-01

    We demonstrate an ultra-stable radio frequency (RF) dissemination scheme over 80 m free space. The frequency dissemination stability is 3.2 × 10(-13)/s and 4.4 × 10(-17)/day, which can be applied to transfer frequency signal without compromising its stability in a global navigation satellite system (GNSS) or radio astronomy. PMID:24182140

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

    NASA Technical Reports Server (NTRS)

    Tyler, G. L.

    1972-01-01

    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.

  10. Satellite orbit determination

    NASA Technical Reports Server (NTRS)

    Jordan, J. F.; Boggs, D. H.; Born, G. H.; Christensen, E. J.; Ferrari, A. J.; Green, D. W.; Hylkema, R. K.; Mohan, S. N.; Reinbold, S. J.; Sievers, G. L.

    1973-01-01

    A historic account of the activities of the Satellite OD Group during the MM'71 mission is given along with an assessment of the accuracy of the determined orbit of the Mariner 9 spacecraft. Preflight study results are reviewed, and the major error sources described. Tracking and data fitting strategy actually used in the real time operations is itemized, and Deep Space Network data available for orbit fitting during the mission and the auxiliary information used by the navigation team are described. A detailed orbit fitting history of the first four revolutions of the satellite orbit of Mariner 9 is presented, with emphasis on the convergence problems and the delivered solution for the first orbit trim maneuver. Also included are a solution accuracy summary, the history of the spacecraft orbit osculating elements, the results of verifying the radio solutions with TV imaging data, and a summary of the normal points generated for the relativity experiment.

  11. Communication satellite services for special purpose users

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  12. RADIO ALTIMETERS

    DOEpatents

    Bogle, R.W.

    1960-11-22

    A radio ranging device is described which utilizes a superregenerative oscillator having alternate sending and receiving phases with an intervening ranging interval between said phases, means for varying said ranging interval, means responsive to an on-range noise reduction condition for stopping said means for varying the ranging interval and indicating means coupled to the ranging interval varying means and calibrated in accordance with one-half the product of the ranging interval times the velocity of light whereby the range is indicated.

  13. Satellite RNAs and Satellite Viruses.

    PubMed

    Palukaitis, Peter

    2016-03-01

    Satellite RNAs and satellite viruses are extraviral components that can affect either the pathogenicity, the accumulation, or both of their associated viruses while themselves being dependent on the associated viruses as helper viruses for their infection. Most of these satellite RNAs are noncoding RNAs, and in many cases, have been shown to alter the interaction of their helper viruses with their hosts. In only a few cases have the functions of these satellite RNAs in such interactions been studied in detail. In particular, work on the satellite RNAs of Cucumber mosaic virus and Turnip crinkle virus have provided novel insights into RNAs functioning as noncoding RNAs. These effects are described and potential roles for satellite RNAs in the processes involved in symptom intensification or attenuation are discussed. In most cases, models describing these roles involve some aspect of RNA silencing or its suppression, either directly or indirectly involving the particular satellite RNA. PMID:26551994

  14. A School Radio Telescope for Two Metres

    ERIC Educational Resources Information Center

    Codling, J. C.

    1973-01-01

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

  15. Numerical Arc-Segmentation Algorithm For A Radio Conference

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Olsen, Donald; Heymann, Roger

    2007-09-01

    The International Telecommunication Union (ITU), a United Nations (UN) agency, is the agency that, under an international treaty, sets radio spectrum usage regulations among member nations. Within the United States of America (USA), the organization that sets regulations, coordinates an application for use, and provides authorization for federal government/agency use of the radio frequency (RF) spectrum is the National Telecommunications and Information Administration (NTIA). In this regard, the NTIA defines which RF spectrum is available for federal government use in the USA, and how it is to be used. The NTIA is a component of the United States (U.S.) Department of Commerce of the federal government. The significance of ITU regulations is that ITU approval is required for U.S. federal government/agency permission to use the RF spectrum outside of U.S. boundaries. All member nations have signed a treaty to do so. U.S. federal regulations for federal use of the RF spectrum are found in the Manual of Regulations and Procedures for Federal Radio Frequency Management, and extracts of the manual are found in what is known as the Table of Frequency Allocations. Nonfederal government and private sector use of the RF spectrum within the U.S. is regulated by the Federal Communications Commission (FCC). There is a need to control "unwanted emissions" (defined to include out-of-band emissions, which are those immediately adjacent to the necessary and allocated bandwidth, plus spurious emissions) to preclude interference to all other authorized users. This paper discusses the causes, effects, and mitigation of unwanted RF emissions to systems in adjacent spectra. Digital modulations are widely used in today's satellite communications. Commercial communications sector standards are covered for the most part worldwide by Digital Video Broadcast - Satellite (DVB-S) and digital satellite news gathering (DSNG) evolutions and the second generation of DVB-S (DVB-S2) standard

  17. Petite Amateur Navy Satellite (PANSAT)

    NASA Technical Reports Server (NTRS)

    Sakoda, D.; Hiser, J. K.

    1989-01-01

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

  18. VLBI observations of geosynchronous satellites

    NASA Astrophysics Data System (ADS)

    Shu, Fengchun; Zhang, Xiuzhong; Zheng, Weimin

    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 ΔDOR (Delta Differential One-way Ranging) error was about 41 cm, and ΔDOD (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.

  19. Radio Jove: Jupiter Radio Astronomy for Citizens

    NASA Astrophysics Data System (ADS)

    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

    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 Jupiter’s 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.

  20. Radio tracking system

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  1. Radio Quiet Protection at the Australian Square Kilometre array site

    NASA Astrophysics Data System (ADS)

    Harvey-Smith, Lisa

    2015-08-01

    Radio astronomy relies on the detection of very faint signals from the universe. Many radio telescopes are now detrimentally affected by radio frequency interference (RFI), which results from a wide range of active spectrum users such as communications, aviation and satellites. This is why many new radio observatories are being sited at increasingly remote locations.The site for the Square Kilometre Array and its pathfinders in Australia is the Murchison Radio-Astronomy Observatory (MRO). The MRO is located more than 350km from the nearest population centre and has a large radio-quiet zone that is managed under a range of legislative agreements.In this talk I will describe the radio quiet zone, what protection it gives, how it works and how astronomers interact with the spectrum management authorities.

  2. Engineers checkout Early Bird-Communication Satellite

    NASA Technical Reports Server (NTRS)

    1984-01-01

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

  3. Microwave and theoretical studies for Cosmic Background Explorer satellite

    NASA Technical Reports Server (NTRS)

    Wilkinson, D. T.

    1983-01-01

    The Cosmic Background Explorer (COBE) satellite, its instruments, and its scientific mission are discussed. The COBE radiometer is considered, and measurement of galactic radio emission with masers is reviewed. Extragalactic radiation and zodiacal dust are mentioned briefly.

  4. Lunar Interferometric Radio Array: LIRA

    NASA Astrophysics Data System (ADS)

    Abbott, J.; Pixton, S.; Roberts, C.; Reyhanoglu, M.

    2000-01-01

    The Lunar Interferometric Radio Array (LIRA) is a performance driven design, with emphasis on utilizing the unique attributes of the far-side of the moon as a platform for radio astronomy. LIRA consists of three independent Lunar Telescope Units (LTUs), autonomously landed on the moon, and a communications relay satellite orbiting at libration point two (L2). Each LTU deploys a large inflatable spheroid, whose underside has been impregnated with a reflective coating. The spheroid is then gradually hardened into a shell by the suns ultraviolet radiation. LIRA achieves broadband capabilities by operating each LTU independently (tuned to offset frequencies), or provides high resolution observations as a three-element interferometer. The interferometer is functional with as few as two elements, yet will achieve greater resolution with additional elements. Thus, LIRA delivers both redundancy and the possibility for future expansion. Data processing, including interferometric synthesis, occurs at an earth-based ground station, eliminating the need for complex onboard data manipulation.

  5. Soviet radio telescopes and solar radio astronomy

    NASA Astrophysics Data System (ADS)

    Alekseev, V. A.; Gel'Freikh, Georgii B.; Zaitsev, Valerii V.; Iliasov, Iurii P.; Kaidanovskii, N. L.

    Soviet radio telescopes of different type and purpose are described, with particular emphasis on very long baseline interferometry. Soviet radio-astronomy studies of solar radio emission and the interplanetary medium are also discussed, with particular attention given to the investigation of the sun's supercorona and the interplanetary plasma.

  6. Coordinated observations of PHEMU at radio wavelengths.

    NASA Astrophysics Data System (ADS)

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

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

  7. Tgf Pulse and Radio Properties Detected at Close Range

    NASA Astrophysics Data System (ADS)

    Cohen, M.; Gross, N. C.; Zoghzoghy, F. G.; Briggs, M. S.; Stanboro, M.; Fitzpatrick, G.

    2014-12-01

    Terrestrial Gamma-ray Flashes (TGFs) are short (10s to 100s of us) energetic (100s to 10000s of keV) discharges originating from the tops of thunderclouds. TGFs have long been associated with radio pulses detected at VLF receivers, but recent evidence indicates that the radio pulse may be from the TGF itself, rather than from a stroke or pulse that either precedes or follows the TGFs. Unfortunately, subionospheric propagation of VLF/LF smooths the radio pulse and destroys in particular the high frequency content, so that the radio signal looks similar to those from ordinary lightning strokes. Since TGFs have a broad range of durations as detected by satellites, these variations should be apparent in the LF radio pulse from the TGF, which may confirm that the TGF is the dominant source of the associated radio pulse and identify a distinguishing feature of TGF-associated pulses. We report on an effort to detect and characterize the LF radio pulses associated with TGFs at close range (<1000 km) with a high sensitivity LF receiver in the Caribbean. This requires some luck and time since TGFs, at least those detectable by satellites, are not especially common. We directly compare the temporal shape of the TGF source to the radio source, after accounting for dead time and Compton scattering to interpret the satellite TGF data, as well as propagation of the LF pulse along the ground to the receiver.

  8. Preface: International Reference Ionosphere and Global Navigation Satellite Systems

    NASA Astrophysics Data System (ADS)

    Bilitza, Dieter; Reinisch, Bodo

    2015-04-01

    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.

  9. Satellite Broadcast of Graphical Weather Data Flight Tested

    NASA Technical Reports Server (NTRS)

    Mallasch, Paul G.

    2000-01-01

    NASA Glenn Research Center at Lewis Field's aviation Weather Information Communications (WINCOMM) and NASA Langley Research Center's Aviation Weather Information (AWIN) programs collaborated in a flight test and evaluation of a worldwide weather data-link capability using satellites. This successful flight testing moves NASA closer to its goal of developing advanced communications and information technologies to enable high-quality and timely dissemination of aviation weather information to all relevant users on the aviation information network. Recognized as a major contributing factor in aviation accidents and incidents, weather contributes directly or indirectly to nearly 80 percent of fatal general aviation (small private aircraft) accidents. In 1997, the Aeronautics Safety Investment Strategy Team s weather team produced a prioritized list of investment areas under weather accident prevention. Weather data dissemination is the most critical and highest ranked priority on the list. NASA's Aviation Safety Program founded the Aviation Weather Information initiative to focus efforts on significantly reducing the number of weather-related aviation fatalities. Access to accurate and timely weather data could contribute to a major reduction of weather-related incidents and accidents. However, a cost-effective solution has eluded most general aviation pilots because of the high cost of onboard weather radar equipment. Rockwell Collins, through a contract with NASA and in cooperation with WorldSpace Corporation, successfully completed ground and flight testing of a receiver and antenna in Johannesburg, South Africa. This NASA/Rockwell Collins project is an evaluation of worldwide weather data-link capability using transmissions from the Satellite Digital Audio Radio Services (S DARS) AfriStar satellite. Owned and operated by WorldSpace, AfriStar is a geostationary satellite that broadcasts commercial digital audio services to stationary and mobile platforms. S DARS

  10. ECS - The European Communication Satellite system

    NASA Astrophysics Data System (ADS)

    Wooster, C. B.

    1981-09-01

    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.