Sample records for research satellite uars

  1. Upper Atmosphere Research Satellite (UARS) science data processing center implementation history

    Herring, Ellen L.; Taylor, K. David


    NASA-Goddard is responsible for the development of a ground system for the Upper Atmosphere Research Satellite (UARS) observatory, whose launch is scheduled for 1991. This ground system encompasses a dedicated Central Data Handling Facility (CDHF); attention is presently given to the management of software systems design and implementation phases for CDHF by the UARS organization. Also noted are integration and testing activities performed following software deliveries to the CDHF. The UARS project has an obvious requirement for a powerful and flexible data base management system; an off-the-shelf commercial system has been incorporated.

  2. Upper Atmosphere Research Satellite (UARS) Microwave Limb Sounder (MLS) mapping - Validation, early results and applications

    Elson, Lee S.; Froidevaux, Lucien; Waters, Joe


    The results of limitation studies performed with the UARS MLS are presented. A consistent set of algorithms allows the extraction of the spectral coefficients in time and longitude from asynoptically sampled satellite data and the subsequent reconstruction of synoptic maps from that spectral information. In addition to providing synoptic maps, the asynoptic technique allows the use of standard spectral analysis tools such as autocorrelation and cross correlation.

  3. Overview and highlights of the UARS mission

    Schoeberl, M.R.; Douglass, A.R.; Jackman, C.H. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)


    The Upper Atmosphere Research Satellite (UARS) was launched in September 1991 with a complement of 10 instruments focused on the middle and upper atmospheric processes, and on solar irradiance variability. After nearly three years of successful UARS operations, eight of the ten instruments continue to operate. Data is routinely processed and reprocessed on a central facility. This data is now being distributed electronically to the scientific community. Among the more important UARS accomplishments are the first global mapping of ozone depleting chlorine radicals and reservoirs, measurement of middle atmosphere winds, the tracking of the Mt. Pinatubo aerosols, and highly accurate measurements of solar ultraviolet variability.

  4. UARS spacecraft recorder


    The objective was the design, development, and fabrication of UARS spacecraft recorders. The UARS recorder is a tailored configuration of the RCA Standard Tape recorder STR-108. The specifications and requirements are reviewed.

  5. Two Views of MLT Winds: TIMED/TIDI and UARS/HRDI

    Skinner, W.; Kafkalidis, J.; Niciejewski, R.; Killeen, T.; Gablehouse, R. D.; Gell, D.; Ortland, D.; Solomon, S. C.; Wu, Q.; Johnson, R.


    The simultaneous operation of two MLT wind sensors, the TIMED Doppler Interferometer (TIDI) and the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS) provides a unique opportunity to inter-calibrate these instruments and to perform scientific investigations that are difficult or impossible with a single instrument. Both instruments are Fabry-Perot interferometers used to measured emission lines in the MLT region. The TIMED and UARS satellites orbit at similar altitudes, but the orbital inclination of TIMED is 74 degrees while that of UARS is 57 degrees. This difference in inclination means that the latitude coverage is different for the two instruments (pole-to-pole for TIDI, +/- 75 degrees for HRDI) and the orbital, and hence local time, precession is significantly faster for UARS (5 degrees/day) than for TIMED (3 degrees/day). There are relatively few opportunities for direct comparisons of observations co-located in space and time. Statistical methods are required to perform the most meaningful comparisons. This paper will discuss the two data sets and illustrate early comparisons between them.

  6. In-flight degradation results for the UARS SOLSTICE instrument

    Woods, Thomas N.; Rottman, Gary J.


    The Solar Stellar Irradiance Comparison Experiment is a three channel spectrometer designed for measuring the solar UV irradiance from 119 to 420 nm with a spectral resolution of 0.1 to 0.3 nm. The three channels are designated as the G, F, and N channels that cover the 119-190 nm, 170-320 nm, and 280-420 nm regions respectively. The SOLSTICE is aboard the NASA Upper Atmosphere Research Satellite (UARS) which was launched on September 12, 1991. The degradation of the SOLSTICE sensitivity is primarily tracked in-flight by measuring a set of bright, early-type stars with the same optics and detectors and by only changing slit sizes and integration times. While the Sun changes by 1 percent in the near UV and by as much as a factor of 2 in the far UV, early-type main sequence stars are not expected to change by more than 1 percent in the UV for long time periods. The ensemble average of the SOLSTICE stellar observation indicate that these stars are indeed stable to 2 percent or better. Since the launch of UARS, the SOLSTICE sensitivity has decreased by a few percent per year. We attribute the degradation primarily to again effects for the photomultiplier tubes for all three channels and to diffusion between layers in the broadband interference filters for the F and N channels. There also appears degradation for the G channel diffraction grating related to excessive heating of the grating on a few days during the UARS mission. There appears only minor degradation associated with optical contamination, mainly because of the strict use of low-outgassing materials in the SOLSTICE instrument and maintenance of class 10,000 clean rooms and oil-free vacuum systems for all pre-flight testing of the SOLSTICE instrument.

  7. Equatorial Kelvin waves: A UARS MLS view

    Canziani, P.O.; Holton, J.R.; Fishbein, E.; Froidevaux, L.; Waters, J.W.


    Data from the Microwave Limb Sounder (MLS) instrument on the Upper Atmosphere Research Satellite (UARS) are used to compare two periods of Kelvin wave activity during different stages of the equatorial quasi-biennial oscillation. The analysis is carried out using an asynoptic mapping technique. A wide bandpass filter is used to isolate the frequency bands where Kelvin waves have been identified in previous studies. Time-height and time-latitude plots of the bandpassed data are used to identify Kelvin wave activity in the temperature and ozone fields. Frequency spectra of temperature and ozone amplitudes are constructed to further analyze the latitudinal and meridional distribution of Kelvin wave activity in zonal wavenumbers 1 and 2. The characteristics identified in these plots agree well with theoretical predictions and previous observations of middle atmosphere Kelvin waves. The time-height and time-latitude plots support the existence of Kelvin waves in discrete frequency bands; the slow, fast, and ultrafast Kelvin modes are all identified in the data. The characteristics of these modes do not vary much despite different mean flow conditions in the two periods examined. For the Kelvin wave-induced perturbations in ozone, the change from a transport-dominated regime below 10 hPa to a photochemically controlled regime above 10 hPa is clearly apparent in the height dependence of the phase difference between temperature and ozone.

  8. Investigation of Tropical Transport with UARS Data

    Dunkerton, Timothy J.


    Measurements of trace constituents obtained by instruments aboard the Upper Atmosphere Research Satellite (UARS) have been used to study transport processes associated with the quasi-biennial oscillation, laterally propagating Rossby waves, and upward propagating Kelvin waves in the tropical and subtropical upper troposphere and stratosphere. Mean vertical motions, vertical diffusivities and in-mixing rates were inferred from observations of the 'tape recorder' signal in near-equatorial stratospheric water vapor. The effect of the quasi-biennial oscillation (QBO) on tracer distributions in the upper half of the stratosphere was seen in a spectacular 'staircase' pattern, predominantly in the winter hemisphere, revealing the latitudinally asymmetric nature of QBO transport due to induced mean meridional circulations and modulation of lateral mixing associated with planetary Rossby waves. The propagation of Rossby waves across the equator in the westerly phase of the QBO was seen in tracer fields and corroborating United Kingdom Meteorological Office (UKMO) analyses; a modeling study of the effect of these waves on typical QBO wind profiles was performed. Water vapor in the upper troposphere and lower stratosphere was found to exhibit signatures of the tropical intraseasonal oscillation (TIO) and faster Kelvin waves in the two regions, respectively.

  9. The Upper Atmosphere Research Satellite microwave limb sounder instrument

    Barath, F. T.; Chavez, M. C.; Cofield, R. E.; Flower, D. A.; Frerking, M. A.; Gram, M. B.; Harris, W. M.; Holden, J. R.; Jarnot, R. F.; Kloezeman, W. G.


    The microwave limb sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) is the first satellite experiment using limb sounding techniques at microwave frequencies. Primary measurement objectives are stratospheric ClO, O3, H2O, temperature, and pressure. Measurements are of thermal emission: all are performed simultaneously and continuously and are not degraded by ice clouds or volcanic aerosols. The instrument has a 1.6-m mechanically scanning antenna system and contains heterodyne radiometers in spectral bands centred near 63, 183, and 205 GHz. The radiometers operate at ambient temperature and use Schottky-diode mixers with local oscillators derived from phase-locked Gunn oscillators. Frequency tripling by varactor multipliers generates the 183- and 205-GHz local oscillators, and quasi-optical techniques inject these into the mixers. Six 15-channel filter banks spectrally resolve stratospheric thermal emission lines and produce an output spectrum every 2 s. Thermal stability is sufficient for 'total power' measurements which do not require fast chopping. Radiometric calibration, consisting of measurements of cold space and an internal target, is performed every 65-s limb scan. Instrument in-orbit performance has been excellent, and all objectives are being met.

  10. Research Supporting Satellite Communications Technology

    Horan Stephen; Lyman, Raphael


    This report describes the second year of research effort under the grant Research Supporting Satellite Communications Technology. The research program consists of two major projects: Fault Tolerant Link Establishment and the design of an Auto-Configurable Receiver. The Fault Tolerant Link Establishment protocol is being developed to assist the designers of satellite clusters to manage the inter-satellite communications. During this second year, the basic protocol design was validated with an extensive testing program. After this testing was completed, a channel error model was added to the protocol to permit the effects of channel errors to be measured. This error generation was used to test the effects of channel errors on Heartbeat and Token message passing. The C-language source code for the protocol modules was delivered to Goddard Space Flight Center for integration with the GSFC testbed. The need for a receiver autoconfiguration capability arises when a satellite-to-ground transmission is interrupted due to an unexpected event, the satellite transponder may reset to an unknown state and begin transmitting in a new mode. During Year 2, we completed testing of these algorithms when noise-induced bit errors were introduced. We also developed and tested an algorithm for estimating the data rate, assuming an NRZ-formatted signal corrupted with additive white Gaussian noise, and we took initial steps in integrating both algorithms into the SDR test bed at GSFC.

  11. WINDII on UARS in the context of SCISAT and Odin

    Shepherd, Gordon G.


    The fundamental elements of the atmosphere are its energy input, composition, temperature and dynamics. Of these the dynamics have had the least observational investigation because of the difficulty of the measurement of winds through optical remote sensing. This article reviews one approach to this topic, the application of the Doppler Michelson Interferometer, focusing on one particular instrument, the Wind Imaging Interferometer (WINDII) flown on NASA's Upper Atmosphere Research Satellite (UARS) from 1991 to 2003. With this concept, the wind is measured through the phase shifts of a single fringe from a Michelson interferometer set to an appropriately large optical path difference, determined by phase stepping over that fringe. This configuration allows the implementation of field-widening, allowing the measurements to be made over a wide field, providing wind images extending from roughly 80 km to 300 km altitude. The Doppler target is the day and night airglow of the upper atmosphere, whose emission rates provide valuable information about the composition of the atmosphere and whose wavelength shifts provide the Doppler information. The primary result, not fully predicted, was the observation of the influence of the dynamics on the composition of the atmosphere. This review provides a minimal instrumentation description, but adequate references, and concentrates on the larger picture of how these data contribute to understanding the interactions of composition, temperature and dynamics, in the context of the SCISAT and Odin measurements. Some new results presented indicate future directions, yet to be explored in full.

  12. Satellite Communications Applications Research

    Lang, Robert J.


    This report describes work performed by SDL in the development of monolithically-integrated master oscillator power amplifiers under the NASA-SCAR research contract. The goals of the program were to demonstrate high power diffraction-limited operation from a semiconductor laser with the following characteristics: (1) Output power of 0.5 to 1.0 W continuous-wave (cw); (2) Single spectral mode with greater than 20 dB of side mode suppression; (3) Single spatial mode operation; (4) Modulation capability of 0.5 GHz; and (5) Operating wavelength between 830-860 nm. Cw diffraction-limited output powers as high as 2.2 W were achieved while maintaining a single longitudinal mode. Side mode suppression ratios greater than 20 dB are typically obtained. The single spatial mode output has a Strehl ratio estimated at 0.85, and a high-speed modulation capability was demonstrated with a small-signal 3-dB roll-off at 1.0 GHz. Finally, all of this performance was obtained in the 860 nm wavelength band, which corresponds to the peak sensitivity of Si detectors. During the first option period, three deliverables were fabricated and delivered that included 1 distributed Bragg reflector (DBR) laser operating at 970 nm, 1 DBR laser operating at 860 nm, and one monolithic flared amplifier master oscillator power amplifier (MFA-MOPA) providing 0.5 W cw diffraction-limited output. During the second option period, a total of 5 MFA-MOPA devices were delivered, each operating to better than 1 W cw diffraction-limited at 860 nm.

  13. Calibration of the Microwave Limb Sounder on the Upper Atmosphere Research Satellite

    Jarnot, R. F.; Cofield, R. E.; Waters, J. W.; Flower, D. A.; Peckham, G. E.


    The Microwave Limb Sounder (MLS) is a three-radiometer, passive, limb emission instrument onboard the Upper Atmosphere Research Satellite (UARS). Radiometric, spectral and field-of-view calibrations of the MLS instrument are described in this paper. In-orbit noise performance, gain stability, spectral baseline and dynamic range are described, as well as use of in-flight data for validation and refinement of prelaunch calibrations. Estimated systematic scaling uncertainties (3 sigma) on calibrated limb radiances from prelaunch calibrations are 2.6% in bands 1 through 3, 3.4% in band 4, and 6% in band 5. The observed systematic errors in band 6 are about 15%, consistent with prelaunch calibration uncertainties. Random uncertainties on individual limb radiance measurements are very close to the levels predicted from measured radiometer noise temperature, with negligible contribution from noise and drifts on the regular in-flight gain calibration measurements.

  14. Investigation of Tropical Dynamics and Transport with UARS Data

    Jackman, Charles (Technical Monitor); Dunkerton, Timothy J.; Mote, Philip W.


    Our research focused on Kelvin waves in the tropical lower stratosphere, and resulted in three papers published or submitted to the Journal of Geophysical Research. The first of these, published in 2002, used temperature data from the Microwave Limb Sounder to examine the amplitude, frequency, phase, and spatial structure of leading modes of Kelvin waves. The second and third, submitted late in 2002 and currently in revision, described the response to Kelvin waves of various trace constituents measured by MLS and CLAES (methane, nitrous oxide, CFC-12, and ozone in the second paper; water vapor in the third paper). Water vapor is a special case because the vertical structure induced by Kelvin waves is convolved with water vapor's seasonally varying vertical profile induced by seasonal variations in temperature at the tropical tropopause. Forward modeling indicated that the vertical resolution of MLS was indeed adequate to capture this complicated structure, yet it was not visible in the MLS data, though the Kelvin wave signature was clear on certain UARS levels. The effects of Kelvin waves on the tropical tropopause and on stratosphere- troposphere exchange cannot be quantified from UARS data because of poor vertical resolution and sensitivity in that region. It is recommended that this analysis be repeated using data from the new MLS and HIRDLS instruments aboard Aura, and that priority be given to fine-scale retrievals of temperature, water vapor, and ozone in the tropical tropopause region.

  15. The Upper Atmosphere Research Satellite: From Coffee Table Art to Quantitative Science

    Douglass, Anne R.


    The Upper Atmosphere Research Satellite (UARS) has provided an unprecedented set of observations of constituents of the stratosphere. When used in combination with data from other sources and appropriate modeling tools, these observations are useful for quantitative evaluation of stratospheric photochemical processes. This is illustrated by comparing ozone observations from airborne Differential Absorption Lidar (DIAL), from the Polar Ozone and Aerosol Measurement (POAM), from the Microwave Limb Sounder (MLS), and from the Halogen occultation Experiment (HALOE) with ozone fields generated with a three dimensional model. For 1995-96, at polar latitudes, observations from DIAL flights on December 9 and January 30, and POAM and MLS between late December and late January are compared with ozone fields from the GSFC 3D chemistry and transport model. Data from the three platforms consistently show that the observed ozone has a negative trend relative to the modeled ozone, and that the trend is uniform in time between early and mid winter, with no obvious dependence on proximity to the vortex edge. The importance of chlorine catalyzed photochemistry to this ozone loss is explored by comparing observations from MLS and HALOE with simulations for other northern winters, particularly 1997-98.

  16. Thermal tides and studies to tune the mechanistic tidal model using UARS observations

    V. A. Yudin

    Full Text Available Monthly simulations of the thermal diurnal and semidiurnal tides are compared to High-Resolution Doppler Imager (HRDI and Wind Imaging Interferometer (WINDII wind and temperature measurements on the Upper-Atmosphere Research Satellite (UARS. There is encouraging agreement between the observations and the linear global mechanistic tidal model results both for the diurnal and semidiurnal components in the equatorial and mid-latitude regions. This gives us the confidence to outline the first steps of an assimilative analysis/interpretation for tides, dissipation, and mean flow using a combination of model results and the global measurements from HRDI and WINDII. The sensitivity of the proposed technique to the initial guess employed to obtain a best fit to the data by tuning model parameters is discussed for the January and March 1993 cases, when the WINDII day and night measurements of the meridional winds between 90 and 110 km are used along with the daytime HRDI measurements. Several examples for the derivation of the tidal variables and decomposition of the measured winds into tidal and mean flow components using this approach are compared with previous tidal estimates and modeling results for the migrating tides. The seasonal cycle of the derived diurnal tidal amplitudes are discussed and compared with radar observation between 80 and 100 km and 40°S and 40°N.

  17. Synoptic Mapping of Chemical Composition, Thermal Structure, and Air Motion from UARS Observations

    Salby, Murry L.


    An operational mapping algorithm was developed to process measurements of individual species observed by different satellite instruments on board UARS. Based on Fast Fourier Synoptic Mapping (FFSM), the algorithm accounts for the precessing orbit of UARS, the error of individual instruments, and gaps associated with instrument duty cycle and the satellite yaw maneuver. It provides synoptic structure and evolution on periods as short as 1 day, derived collectively from all observations of an individual species. The algorithm was applied to synoptically map temperature, thickness, and several chemical constituents observed by the instruments: MLS, CLAES, ISAMS, and HALOE. Each field variable observed by these instruments was mapped twice-daily in continuous global time series several months long. Mapped behavior produced via FFSM was compared against standard archived products generated via Kalman filtering. The standard map products reveal similar behavior, but are limited to features of larger scale. Tracer structure that develops through flow deformation and attending transport is therefore represented in those products more coarsely, eventually being sheared down to scales that are no longer represented properly. The synoptic time series also reveal a diurnal cycle for several of the constituents, one that emerges clearly in their space-time spectra. The zonal and meridional structure of diurnal variability was mapped by filtering the space-time spectrum, an intermediate product of FFSM, to those scales resolved by the UARS sampling. Geographical variations of the diurnal cycle have also been evaluated in its seasonal-mean structure by compositing distributions at individual local times. Both were compared to diurnal variations in chemical models and in dynamical models that account for transport by the diurnal tide. Diurnal variations were found to introduce spurious behavior into the archived products generated via Kalman filtering, behavior that is

  18. Establishing a long-term, global stratospheric HNO3 data record combining UARS MLS with Aura MLS data by means of ground-based measurements

    Fiorucci, I.; Muscari, G.; Froidevaux, L.; Santee, M. L.; de Zafra, R. L.


    Nitric Acid (HNO3) is a major player in processes controlling stratospheric ozone depletion. It is a primary reservoir for reactive nitrogen in the stratosphere and has a key role in both the activation and the deactivation of chlorine and bromine species. Since 1993 HNO3 observations have been carried out by means of a Ground-Based Millimeter-wave Spectrometer (GBMS) from a variety of sites in both hemispheres, at polar and mid-latitudes. The GBMS observes a cluster of weak emission lines centered at 269 GHz, with a pass band of 600 MHz and a resolution of 1 MHz. The retrieval of vertical profiles from the pressure-blended multiple line spectra is carried out with an Optimal Estimation Method. The GBMS provides HNO3 profiles from ~15 up to 50 km, with a vertical resolution of 6-8 km and a total uncertainty of ~15%. GBMS HNO3 measurements have been used within GOZCARDS (Global Ozone Chemistry and Related Trace gas Data Records for the Stratosphere), a multi-year MEaSUREs project, aimed at developing a long-term, commonly-formatted Earth system data record (ESDR) of stratospheric constituents relevant to the issues of ozone decline and expected recovery. This data record is based mainly on satellite-derived measurements. Nevertheless, ground-based observations can be critically used for assessing offsets between satellite data sets, as well as to fill gaps in temporal coverage when possible. Since the GBMS has been operated for more than 15 years (with minor instrumental upgrading), the GBMS HNO3 data record is well-suited for the GOZCARDS objectives; it offers a unique opportunity for the cross-calibration of HNO3 measurements from the NASA/JPL Microwave Limb Sounder (MLS) experiments (aboard the Upper Atmosphere Research Satellite (UARS) from 1991 to 1999, and on the Earth Observing System (EOS) Aura mission from 2004 to date). In this study we compare Aura MLS observations and GBMS HNO3 measurements obtained from the Italian Alpine station of Plateau Rosa, during

  19. Coupled aerosol-chemical modeling of UARS HNO3 and N2O5 measurements in the Arctic upper stratosphere

    Bekki, S.; Chipperfield, M. P.; Pyle, J. A.; Remedios, J. J.; Smith, S. E.; Grainger, R. G.; Lambert, A.; Kumer, J. B.; Mergenthaler, J. L.


    Gas-phase photochemical models do not account for the formation of a secondary altitude HNO3 maximum in the upper stratosphere at high latitudes during winter, suggesting that some processes are missing in the currently accepted chemistry of reactive nitrogen species [Kawa et al, 1995]. Heterogeneous chemistry on aerosol particles had been discounted as the cause because the aerosol surface area is expected to be very low at these altitudes. We have coupled a sulphate aerosol microphysical model to a chemical transport model to investigate this model deficiency in the Arctic during January 1992. The aerosol model predicts the formation of small sulphate particles at 1100 K. Comparisons with cryogenic limb array etalon spectrometer (CLAES) HNO3 and improved stratospheric and mesospheric sounder (ISAMS) N2O5 observations show that the heterogeneous conversion of N2O5 to HNO3 on the modeled small sulphate particles can account for some of the unexpected features seen in Upper Atmosphere Research Satellite (UARS) observations.

  20. Observer-based Satellite Attitude Control and Simulation Researches

    王子才; 马克茂


    Observer design method is applied to the realization of satellite attitude control law baaed on simplified control model. Exact mathematical model of the satellite attitude control system is also constructed, together with the observer-based control law, to conduct simulation research. The simulation results justify the effectiveness andfeasibility of the observer-based control method.

  1. The UARS and open data system concept and analysis study. Executive summary

    Mittal, M.; Nebb, J.; Woodward, H.


    Alternative concepts for a common design for the UARS and OPEN Central Data Handling Facility (CDHF) are offered. The designs are consistent with requirements shared by UARS and OPEN and the data storage and data processing demands of these missions. Because more detailed information is available for UARS, the design approach was to size the system and to select components for a UARS CDHF, but in a manner that does not optimize the CDHF at the expense of OPEN. Costs for alternative implementations of the UARS designs are presented showing that the system design does not restrict the implementation to a single manufacturer. Processing demands on the alternative UARS CDHF implementations are discussed. With this information at hand together with estimates for OPEN processing demands, it is shown that any shortfall in system capability for OPEN support can be remedied by either component upgrades or array processing attachments rather than a system redesign.

  2. Photometrical research geostationary satellite "SBIRS GEO-2"

    Sukhov, P. P.; Epishev, V. P; Sukhov, K. P; Kudak, V. I.

    The multicolor photometrical observations GSS "Sbirs Geo-2" were carried in B,V,R filters out during the autumn equinox 2014 and spring 2015 y. Periodic appearance of many light curves and dips of mirror reflections suggests that the GSS was not in orbit in a static position, predetermined three-axis orientation and in dynamic motion. On the basis of computer modeling suggests the following dynamics GSS "Sbirs Geo-2" in orbit. Helically scanning the visible Earth's surface infrared satellite sensors come with period P1 = 15.66 sec. and the rocking of the GSS about the direction of the motion vector of the satellite in orbit with P2 = 62.64 sec., most likely with the purpose to survey the greatest possible portion of the earth's surface.

  3. UARS Halogen Occultation Experiment (HALOE) Level 2 V001

    National Aeronautics and Space Administration — The HALOE home page on the WWW is The Halogen Occultation Experiment (HALOE) on NASA's Upper Atmosphere Research Satellite...

  4. Central Satellite Data Repository Supporting Research and Development

    Han, W.; Brust, J.


    Near real-time satellite data is critical to many research and development activities of atmosphere, land, and ocean processes. Acquiring and managing huge volumes of satellite data without (or with less) latency in an organization is always a challenge in the big data age. An organization level data repository is a practical solution to meeting this challenge. The STAR (Center for Satellite Applications and Research of NOAA) Central Data Repository (SCDR) is a scalable, stable, and reliable repository to acquire, manipulate, and disseminate various types of satellite data in an effective and efficient manner. SCDR collects more than 200 data products, which are commonly used by multiple groups in STAR, from NOAA, GOES, Metop, Suomi NPP, Sentinel, Himawari, and other satellites. The processes of acquisition, recording, retrieval, organization, and dissemination are performed in parallel. Multiple data access interfaces, like FTP, FTPS, HTTP, HTTPS, and RESTful, are supported in the SCDR to obtain satellite data from their providers through high speed internet. The original satellite data in various raster formats can be parsed in the respective adapter to retrieve data information. The data information is ingested to the corresponding partitioned tables in the central database. All files are distributed equally on the Network File System (NFS) disks to balance the disk load. SCDR provides consistent interfaces (including Perl utility, portal, and RESTful Web service) to locate files of interest easily and quickly and access them directly by over 200 compute servers via NFS. SCDR greatly improves collection and integration of near real-time satellite data, addresses satellite data requirements of scientists and researchers, and facilitates their primary research and development activities.

  5. Satellite Communications for Aeronautical Applications: Recent research and Development Results

    Kerczewski, Robert J.


    Communications systems have always been a critical element in aviation. Until recently, nearly all communications between the ground and aircraft have been based on analog voice technology. But the future of global aviation requires a more sophisticated "information infrastructure" which not only provides more and better communications, but integrates the key information functions (communications, navigation, and surveillance) into a modern, network-based infrastructure. Satellite communications will play an increasing role in providing information infrastructure solutions for aviation. Developing and adapting satellite communications technologies for aviation use is now receiving increased attention as the urgency to develop information infrastructure solutions grows. The NASA Glenn Research Center is actively involved in research and development activities for aeronautical satellite communications, with a key emphasis on air traffic management communications needs. This paper describes the recent results and status of NASA Glenn's research program.

  6. Research from an Operatonal Space Weather Satellite

    de Koning, C. A.


    STEREO real-time white-light images, or beacon images, are heavily compressed, 256x256 pixel images. And yet, they show the same transient features that are in the STEREO science images, which are up to 2048x2048 pixels. Based on our experience with STEREO beacon images, we demonstrate that operational images can be used to do good quality science. We also discuss the limitations of operational data for scientific research. Finally, we discuss ways in which a predominantly operational mission could be combined with science mission, to further enhance research.

  7. The Mesospheric Wind Field as Measured by TIMED/TIDI and UARS/HRDI from 2002 to 2005

    Skinner, W. R.; Gell, D.; Cooper, M.; Niciejewski, R.; Killeen, T. L.; Solomon, S. C.; Wu, Q.; Ortlad, D.; Marshall, A.


    The TIMED Doppler Interferometer (TIDI) has been measuring winds in the mesosphere and lower thermosphere since the beginning of 2002. From the beginning of the TIMED mission until March 2005, the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Satellite (UARS) also measured winds in the same region. It is very desirable to compare the wind field from the two instruments. This three year overlap permits a comprehensive validation of the winds and more importantly allows scientific studies that are difficult or impossible with a single data set. For example, tidal analysis with one instrument requires assumptions about structure of the tide for analysis to proceed. Difficulties in removing instrument artifacts in the TIDI data and correcting for a loss of precision attitude knowledge on the UARS spacecraft have so far prevented these studies. These problems are now largely resolved. This paper will compare the two data sets during the time of mutual operation. The data coverage and accuracies will be discussed as well as the times when the data is best used for validation and when for two instrument scientific studies.

  8. SCARF - The Swarm Satellite Constellation Application and Research Facility

    Olsen, Nils


    Swarm, a three-satellite constellation to study the dynamics of the Earth's magnetic field and its interactions with the Earth system, has been launched in November 2013. The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal evolution, which...... will bring new insights into the Earth system by improving our understanding of the Earth's interior and environment. In order to take advantage of the unique constellation aspect of Swarm, considerably advanced data analysis tools have been developed. Scientific users will also benefit significantly from...... derived products, the so-called Level-2 products, that take into account the features of the constellation. The Swarm SCARF (Satellite Constellation Application and Research Facility), a consortium of several research institutions, has been established with the goal of deriving Level-2 products...

  9. The 2010 IADR--Geriatric Oral Research Group satellite meeting.

    Schimmel, Martin


    On 12 and 13 July, the 2010 IADR General Session satellite meeting of the IADR - Geriatric Oral Research Group (GORG) - was attended by around 60 participants in the beautiful surroundings of Sitges in the outskirts of Barcelona, Spain. The speakers reflected on the main topics 'Disparities and Expectations in Oral Healthcare: An Elderly Focus' and 'Risks and Benefits of Ageing with a Natural Dentition', which was followed by fruitful discussions in the auditorium and the jointly enjoyed meals. The Sitges meeting comprised lectures of distinguished speakers as well as poster presentations, which discussed and defined the situation of research in the field of gerodontology today as well as the development since the last GORG satellite symposium held on Vancouver Island in 1999. Despite enormous progress over the last 10 years, many important questions concerning economics, regulation, the implementation of oral health care, treatment protocols as well as general health implications of oral disease in the frail and elderly remain still unanswered.

  10. Snow, Ice, & Satellites: An Early Career Researcher's Experience with Twitter

    Pope, A.; Scambos, T. A.


    As a doctoral student, I was lucky enough to be able to experiment with a variety of communication and outreach activities (classroom visits, museum events, science festivals, blogging, social media, etc.) to build communication skills and learn how to talk about my science without writing a journal article. More importantly, the wide range of experience helped me identify what worked for me. My favorite way to share my science now? Twitter. To many, Twitter is a frivolous platform for sharing snippets 140 characters or less. To me, however, it is how I can connect directly with the elusive "wider public" and share my science. Specifically, I use satellite imagery (mostly Landsat 8) to study glaciers around the world. I look at long-term change related to climate, and I also investigate new, innovative ways to use satellite imagery to better understand glaciers and ice sheets. Luckily for me, my research is very visual. Whether fieldwork snapshots or satellite data, images make for great, shareable, accessible tweets. In this presentation, I propose to share my experience of tweeting as an early career researcher. I will include successful strategies (e.g. particular #hashtags, creating new content, using story-telling, timely tweets), as well as some not-so-successful attempts. I will also talk about how I built my Twitter network. In addition to anecdotes, I will include evaluation of my Twitter activity using available metrics and analytics (e.g. followers, favorites, re-tweets, Klout score, etc.). While misunderstood by many in the scientific community, Twitter is a platform increasingly being adopted by researchers. Used correctly, it can be a great tool for connecting directly with an interested, non-technical audience eager to learn about your research. With my experiences and evaluation, I will show how both scientists and the networks that they join and create can benefit by using Twitter as a platform for science communication.

  11. Research-related intercultural higher education in satellite geodesy

    Mayer, M.; Heck, B.; Krueger, C. P.


    In order to improve the education of young researchers (master degree, PhD, PostDocs) a cooperation between the Department of Geomatics (DGEOM), Federal University of Paraná (UFPR), Curitiba (Brazil) and the Geodetic Institute (GIK), University Karlsruhe (TH), Karlsruhe (Germany) was established which now exists since more than five years. The joint venture is actually called "PROBRAL: Precise positioning and height determination by means of GPS: Modeling of errors and transformation into physical heights" and focuses on research and education within the field of satellite geodesy. PROBRAL is funded by the Brazilian academic exchange service CAPES and the German academic exchange service DAAD. The geodetic aim of the research project is to validate and improve the quality of 3d positions derived from observations related to satellite navigation systems like GPS. In order to fulfill this ambitious goal sustainably, research has to be carried out in close cooperation. At the same time, e.g. to guarantee continuous success, a coordinated education has to be ensured. Besides technical education aspects key competences (e.g. language, capacity for teamwork, project management skills) are trained. Within the presentation the lessons which were learned from this project are discussed in detail.

  12. The microwave limb sounder for the Upper Atmosphere Research Satellite

    Waters, J. W.; Peckham, G. E.; Suttie, R. A.; Curtis, P. D.; Maddison, B. J.; Harwood, R. S.


    The Microwave Limb Sounder was designed to map the concentrations of trace gases from the stratosphere to the lower thermosphere, to improve understanding of the photochemical reactions which take place in this part of the atmosphere. The instrument will measure the intensity of thermal radiation from molecules in the atmosphere at frequencies corresponding to rotational absorption bands of chlorine monoxide, ozone, and water vapor. Molecular concentration profiles will be determined over a height range of 15 to 80 km (20 to 45 km for C10). The 57 deg inclination orbit proposed for the Upper Atmosphere Research Satellite will allow global coverage.

  13. High-Resolution Satellite Data Open for Government Research

    Neigh, Christopher S. R.; Masek, Jeffrey G.; Nickeson, Jaime E.


    U.S. satellite commercial imagery (CI) with resolution less than 1 meter is a common geospatial reference used by the public through Web applications, mobile devices, and the news media. However, CI use in the scientific community has not kept pace, even though those who are performing U.S. government research have access to these data at no cost.Previously, studies using multiple CI acquisitions from IKONOS-2, Quickbird-2, GeoEye-1, WorldView-1, and WorldView-2 would have been cost prohibitive. Now, with near-global submeter coverage and online distribution, opportunities abound for future scientific studies. This archive is already quite extensive (examples are shown in Figure 1) and is being used in many novel applications.

  14. The UARS and open data concept and analysis study. [upper atmosphere

    Mittal, M.; Nebb, J.; Woodward, H.


    Alternative concepts for a common design for the UARS and OPEN Central Data Handling Facility (CDHF) are offered. Costs for alternative implementations of the UARS designs are presented, showing that the system design does not restrict the implementation to a single manufacturer. Processing demands on the alternative UARS CDHF implementations are then discussed. With this information at hand together with estimates for OPEN processing demands, it is shown that any shortfall in system capability for OPEN support can be remedied by either component upgrades or array processing attachments rather than a system redesign. In addition to a common system design, it is shown that there is significant potential for common software design, especially in the areas of data management software and non-user-unique production software. Archiving the CDHF data are discussed. Following that, cost examples for several modes of communications between the CDHF and Remote User Facilities are presented. Technology application is discussed.

  15. The German joint research project "concepts for future gravity satellite missions"

    Reubelt, Tilo; Sneeuw, Nico; Fichter, Walter; Müller, Jürgen


    Within the German joint research project "concepts for future gravity satellite missions", funded by the Geotechnologies programme of the German Federal Ministry of Education and Research, options and concepts for future satellite missions for precise (time-variable) gravity field recovery are investigated. The project team is composed of members from science and industry, bringing together experts in geodesy, satellite systems, metrology, sensor technology and control systems. The majority of team members already contributed to former gravity missions. The composition of the team guarantees that not only geodetic aspects and objectives are investigated, but also technological and financial constraints are considered. Conversely, satellite, sensor and system concepts are developed and improved in a direct exchange with geodetic and scientific claims. The project aims to develop concepts for both near and mid-term future satellite missions, taking into account e.g. advanced satellite formations and constellations, improved orbit design, innovative metrology and sensor systems and advances in satellite systems.

  16. Comparison of the Changes in the Visible and Infrared Irradiance Observed by the SunPhotometers on EURECA to the UARS Total Solar and UV Irradiances

    Pap, Judit


    Solar irradiance in the near-UV (335 nm), visible (500 nm) and infrared (778 nm) spectral bands has been measured by the SunPhotometers developed at the World Radiation Center, Davos, Switzerland on board the European Retrievable Carrier between August 1992 and May 1993. Study of the variations in the visible and infrared irradiance is important for both solar and atmospheric physics. The purpose of this paper is to examine the temporal variations observed in the visible and infrared spectral bands after eliminating the trend in the data mainly related to instrument degradation. The effect of active regions in these spectral irradiances is clearly resolved. Variations in the visible and infrared irradiances are compared to total solar irradiance observed by the SOVA2 radiometer on the EURECA platform and by the ACRIMII radiometer on UARS as well as to UV observations of the UARS and NOAA9 satellites. The space-borne spectral irradiance observations are compared to the photometric sunspot deficit and CaII K irradiance measured at the San Fernando Observatory, California State University at Northridge in order to study the effect of active regions in detail.

  17. Comparison of the Changes in the Visible and Infrared Irradiance Observed by the SunPhotometers on EURECA to the UARS Total Solar and UV Irradiances

    Pap, Judit


    Solar irradiance in the near-UV (335 nm), visible (500 nm) and infrared (778 nm) spectral bands has been measured by the SunPhotometers developed at the World Radiation Center, Davos, Switzerland on board the European Retrievable Carrier between August 1992 and May 1993. Study of the variations in the visible and infrared irradiance is important for both solar and atmospheric physics. The purpose of this paper is to examine the temporal variations observed in the visible and infrared spectral bands after eliminating the trend in the data mainly related to instrument degradation. The effect of active regions in these spectral irradiances is clearly resolved. Variations in the visible and infrared irradiances are compared to total solar irradiance observed by the SOVA2 radiometer on the EURECA platform and by the ACRIMII radiometer on UARS as well as to UV observations of the UARS and NOAA9 satellites. The space-borne spectral irradiance observations are compared to the photometric sunspot deficit and CaII K irradiance measured at the San Fernando Observatory, California State University at Northridge in order to study the effect of active regions in detail.

  18. Comparisons between Canadian prairie MF radars, FPI (green and OH lines and UARS HRDI systems

    C. E. Meek

    Full Text Available Detailed comparisons have been completed between the MF radars (MFR in the Canadian prairies and three other systems: two ground-based Fabry-Perot interferometers (FPI and the UARS high resolution Doppler imager (HRDI system. The radars were at Sylvan Lake (52°N, 114°W, Robsart 
    (49°N, 109°W and the main continuing facility is at Saskatoon (52°N, 107°W. Statistical comparisons of hourly mean winds (1988-1992 for the Saskatoon MFR and FPI (557.7 nm green line using scatter plots, wind speed-ratios, and direction-difference histograms show excellent agreement for Saskatoon. No serious biases in speeds or directions occur at the height of best agreement, 98 km. If anything, the MFR speeds appear bigger. The same applies to the Sylvan Lake MFR and Calgary FPI, where the best height is 88 km. In both cases these are close to the preferred heights for the emission layers. Differences between measurements seen on individual days are likely related to the influence of gravity waves (GW upon the optical and radar systems, each of which have inherent spatial averaging (350, 50 km respectively, as well as the spatial difference between the nominal measurement locations. For HRDI, similar statistical comparisons are made, using single-overpass satellite winds and hourly means (to improve data quality from MFR. Heights of best agreement, based upon direction-difference histograms, are shown; there is a tendency, beginning near 87 km, for these MFR heights to be 2 or 3 km greater than the HRDI heights. Speeds at these heights are typically larger for the satellite (MFR/HRDI = 0.7–0.8. Reasons for the differences are investigated. It is shown that the estimated errors and short-term (90 min differences are larger for HRDI than for the MFR, indicating more noise or GW contamination. This leads to modest but significant differences in median speed-ratio (MFR/HRDI < 1. Also, comparison


    Ning Jinsheng


    This is a summarized paper. Two topics are discussed: Firstly, the concept, development and application of four kinds of satellite gravity surveying technology are introduced; Secondly, some problems of theory and method, which must be considered in the study of the Earth's gravity field based on satellite gravity data, are expounded.

  20. Review: Advances in delta-subsidence research using satellite methods

    Higgins, Stephanie A.


    Most of the world's major river deltas are sinking relative to local sea level. The effects of subsidence can include aquifer salinization, infrastructure damage, increased vulnerability to flooding and storm surges, and permanent inundation of low-lying land. Consequently, determining the relative importance of natural vs. anthropogenic pressures in driving delta subsidence is a topic of ongoing research. This article presents a review of knowledge with respect to delta surface-elevation loss. The field is rapidly advancing due to applications of space-based techniques: InSAR (interferometric synthetic aperture radar), GPS (global positioning system), and satellite ocean altimetry. These techniques have shed new light on a variety of subsidence processes, including tectonics, isostatic adjustment, and the spatial and temporal variability of sediment compaction. They also confirm that subsidence associated with fluid extraction can outpace sea-level rise by up to two orders of magnitude, resulting in effective sea-level rise that is one-hundred times faster than the global average rate. In coming years, space-based and airborne instruments will be critical in providing near-real-time monitoring to facilitate management decisions in sinking deltas. However, ground-based observations continue to be necessary for generating complete measurements of surface-elevation change. Numerical modeling should seek to simulate couplings between subsidence processes for greater predictive power.

  1. High resolution Doppler imager on the Upper Atmosphere Research Satellite

    Skinner, W.R.; Hays, P.B.; Grassl, H.J.; Gell, D.A.; Burrage, M.D.; Marshall, A.R.; Ortland, D.A. [Univ. of Michigan, Ann Arbor, MI (United States)


    The High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite has been providing measurements of the wind field in the stratosphere, mesosphere and lower thermosphere since November 1991. Examination of various calibration data indicates the instrument has remained remarkably stable since launch. The instrument has a thermal drift of about 30 m/s/{degree}C (slightly dependent on wavelength) and a long-term temporal drift that has amounted to about 80 m/s since launch. These effects are removed in the data processing leaving an uncertainty in the instrument stability of {minus}2 nVs. The temperature control of the instrument has improved significantly since launch as a new method was implemented. The initial temperature control held the instrument temperature at about {+-}1{degree}C. The improved method, which holds constant the temperature of the optical bench instead of the radiator, keeps the instrument temperature at about 0.2{degree}C. The calibrations indicate very little change in the sensitivity of the instrument. The detector response has shown no degradation and the optics have not changed their transmittance.

  2. Satellite telemetry : a new tool for wildlife research and management

    US Fish and Wildlife Service, Department of the Interior — The U.S. Fish and Wildlife Service and the Alaska Department of Fish and Game have cooperated since 1984 to develop and evaluate satellite telemetry as a means of...

  3. Micro-propulsion research; challenges towards future nano-satellite projects

    Cervone, A.; Zandbergen, B.; Bouwmester, J.; Guo, J.


    The Space Systems Engineering department at the Faculty of Aerospace Engineering is hard at work miniaturizing satellite subsystems to accommodate the growing use of small satellites. One of the challenges the department has taken on is research into micro-propulsion. The limitations that come with

  4. Research on Coal Exploration Technology Based on Satellite Remote Sensing

    Dong Xiao


    Full Text Available Coal is the main source of energy. In China and Vietnam, coal resources are very rich, but the exploration level is relatively low. This is mainly caused by the complicated geological structure, the low efficiency, the related damage, and other bad situations. To this end, we need to make use of some advanced technologies to guarantee the resource exploration is implemented smoothly and orderly. Numerous studies show that remote sensing technology is an effective way in coal exploration and measurement. In this paper, we try to measure the distribution and reserves of open-air coal area through satellite imagery. The satellite picture of open-air coal mining region in Quang Ninh Province of Vietnam was collected as the experimental data. Firstly, the ENVI software is used to eliminate satellite imagery spectral interference. Then, the image classification model is established by the improved ELM algorithm. Finally, the effectiveness of the improved ELM algorithm is verified by using MATLAB simulations. The results show that the accuracies of the testing set reach 96.5%. And it reaches 83% of the image discernment precision compared with the same image from Google.

  5. Satellite communications provisions on NASA Ames instrumented aircraft platforms for Earth science research/applications

    Shameson, L.; Brass, J. A.; Hanratty, J. J.; Roberts, A. C.; Wegener, S. S.


    Earth science activities at NASA Ames are research in atmospheric and ecosystem science, development of remote sensing and in situ sampling instruments, and their integration into scientific research platform aircraft. The use of satellite communications can greatly extend the capability of these agency research platform aircraft. Current projects and plans involve satellite links on the Perseus UAV and the ER-2 via TDRSS and a proposed experiment on the NASA Advanced Communications Technology Satellite. Provisions for data links on the Perseus research platform, via TDRSS S-band multiple access service, have been developed and are being tested. Test flights at Dryden are planned to demonstrate successful end-to-end data transfer. A Unisys Corp. airborne satcom STARLink system is being integrated into an Ames ER-2 aircraft. This equipment will support multiple data rates up to 43 Mb/s each via the TDRS S Ku-band single access service. The first flight mission for this high-rate link is planned for August 1995. Ames and JPL have proposed an ACTS experiment to use real-time satellite communications to improve wildfire research campaigns. Researchers and fire management teams making use of instrumented aircraft platforms at a prescribed burn site will be able to communicate with experts at Ames, the U.S. Forest Service, and emergency response agencies.

  6. Small Satellites and RPAs in Global-Change Research


    Cornwall F. Dyson N. Fortson R. Garwin S. Koonin C. Max G. MacDonald S. Ride M. Ruderman S. Treiman J. Vesecky R. Westervelt F. Zachariasen Global-Change Research1 6. AUTHOR(S) PR - 8503A P. Banks, J. Cornwall , F. Dyson, N. Fortson, F. Garwin, S. Koonin, C. Max, G. MacDonald, S. Ride, 2. Charlson, R., J. Lovelock, M. Andreae , and S. Warren (1987) Oceanic phytoplankton, atmospheric sulfur, cloud albedo and climate. Nature 326

  7. Exploratory investigation of the need for and feasibility of a Lower Atmosphere Research Satellite (LARS) program


    The need for and feasibility of a research satellite program for the intensive study of the lower atmosphere (the troposphere and lower stratosphere) is discussed. The priorities for scientific investigation of the lower atmosphere during the next decade are examined. The findings of the study are concerned with identification of those broad research issues of highest priority and, in particular, with those that are most appropriate for investigation from space platforms.

  8. Research on the flywheel components' disturbance mechanism of a high resolution optical satellite

    Lin, Li; Dong, Wang; Sitong, Zhou; Tan, Luyang


    According to the picture of a sub-meter resolution optical satellite acquired on the orbit, there is a phenomenon of jitter in the process of taking pictures. The flywheel as the main attitude control component of the satellite, the disturbance that it caused has great influence on the high resolution optical satellite in its normal action. This paper has respectively researched the flywheel components' disturbance mechanism from three parts, including uneven rotator, rotator friction, bearing disturbance, builds the mathematics model of disturbance to analysis the characteristic of disturbance. we get that the vibration system is not a fully linear system, the system is linear before the occurrence of rubbing. It also can be seen that the system has a number of different cross rigidity, it will often appear unstable motion that resulting in damage, or becomes the ultimate destruction due to the role of nonlinear damping. When the rolling roll in the surface, it will produce an alternative excitation force if there exist defects or damage in the rolling surface. This research would offer guidance for system optimization design and vibrating isolation compensation of the later type of improved satellite.

  9. A Research on Errors in Two-way Satellite Time and Frequency Transfer

    Wu, W. J.


    The two-way satellite time and frequency transfer (TWSTFT) is one of the most accurate means for remote clock comparison with an uncertainty in time of less than 1 ns and with a relative uncertainty in frequency of about 10^{-14} d^{-1}. The transmission paths of signals between two stations are almost symmetrical in the TWSTFT. In principal, most of all kinds of path delays are canceled out, which guarantees the high accuracy of TWSTFT. With the development of TWSTFT and the increase in the frequence of observations, it is showed that the diurnal variation of systematic errors is about 1˜3 ns in the TWSTFT. This problem has become a hot topic of research around the world. By using the data of Transfer Satellite Orbit Determination Net (TSODN) and international TWSTFT links, the systematic errors are studied in detail as follows: (1) The atmospheric effect. This includes ionospheric and tropospheric effects. The tropospheric effect is very small, and it can be ignored. The ionospheric error can be corrected by using the IGS ionosphere product. The variations of ionospheric effect are about 0˜0.05 ns and 0˜0.7 ns at KU band and C band, respectively, and have the diurnal variation characteristics. (2) The equipment time delay. The equipment delay is closely related with temperature, presenting a linear relation at the normal temperature. Its outdoor part indicates the characteristics of the diurnal variation with the environment temperature. The various kinds of effects related with the modem are studied. Some resolutions are proposed. (3) The satellite transponder effect. This effect is studied by using the data of international TWSTFT links. It is analyzed that different satellite transponders can highly increase the amplitude of the diurnal variation in one TWSTFT link. This is the major reason of the diurnal variation in the TWSTFT. The function fitting method is used to basically solve this problem. (4) The satellite motion effect. The geostationary


    K. M. Lyapishev


    Full Text Available This article is an overview of researches of landslides using remote sensing methods such as aerial photography, satellite images, radar interferometry, and their combination with the use of GIS technology. Modern methods of investigation of landslides are very diverse. The authors propose different approaches to the identification, classification and monitoring of landslides. Data analysis techniques can help in creating more sophisticated approach to the analysis of landslides.

  11. Computational Research on Mobile Pastoralism Using Agent-Based Modeling and Satellite Imagery.

    Takuto Sakamoto

    Full Text Available Dryland pastoralism has long attracted considerable attention from researchers in diverse fields. However, rigorous formal study is made difficult by the high level of mobility of pastoralists as well as by the sizable spatio-temporal variability of their environment. This article presents a new computational approach for studying mobile pastoralism that overcomes these issues. Combining multi-temporal satellite images and agent-based modeling allows a comprehensive examination of pastoral resource access over a realistic dryland landscape with unpredictable ecological dynamics. The article demonstrates the analytical potential of this approach through its application to mobile pastoralism in northeast Nigeria. Employing more than 100 satellite images of the area, extensive simulations are conducted under a wide array of circumstances, including different land-use constraints. The simulation results reveal complex dependencies of pastoral resource access on these circumstances along with persistent patterns of seasonal land use observed at the macro level.

  12. Improving the Transition of Earth Satellite Observations from Research to Operations

    Goodman, Steven J.; Lapenta, William M.; Jedlovec, Gary J.


    There are significant gaps between the observations, models, and decision support tools that make use of new data. These challenges include: 1) Decreasing the time to incorporate new satellite data into operational forecast assimilation systems, 2) Blending in-situ and satellite observing systems to produce the most accurate and comprehensive data products and assessments, 3) Accelerating the transition from research to applications through national test beds, field campaigns, and pilot demonstrations, and 4) Developing the partnerships and organizational structures to effectively transition new technology into operations. At the Short-term Prediction Research and Transition (SPORT) Center in Huntsville, Alabama, a NASA-NOAA-University collaboration has been developed to accelerate the infusion of NASA Earth science observations, data assimilation and modeling research into NWS forecast operations and decision-making. The SPoRT Center research focus is to improve forecasts through new observation capability and the regional prediction objectives of the US Weather Research Program dealing with 0-1 day forecast issues such as convective initiation and 24-hr quantitative precipitation forecasting. The near real-time availability of high-resolution experimental products of the atmosphere, land, and ocean from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Advanced Infrared Spectroradiometer (AIRS), and lightning mapping systems provide an opportunity for science and algorithm risk reduction, and for application assessment prior to planned observations from the next generation of operational low Earth orbiting and geostationary Earth orbiting satellites. This paper describes the process for the transition of experimental products into forecast operations, current products undergoing assessment by forecasters, and plans for the future. The SPoRT Web page is at (

  13. Magnetic resonance imaging research in sub-Saharan Africa: challenges and satellite-based networking implementation.

    Latourette, Matthew T; Siebert, James E; Barto, Robert J; Marable, Kenneth L; Muyepa, Anthony; Hammond, Colleen A; Potchen, Michael J; Kampondeni, Samuel D; Taylor, Terrie E


    As part of an NIH-funded study of malaria pathogenesis, a magnetic resonance (MR) imaging research facility was established in Blantyre, Malaŵi to enhance the clinical characterization of pediatric patients with cerebral malaria through application of neurological MR methods. The research program requires daily transmission of MR studies to Michigan State University (MSU) for clinical research interpretation and quantitative post-processing. An intercontinental satellite-based network was implemented for transmission of MR image data in Digital Imaging and Communications in Medicine (DICOM) format, research data collection, project communications, and remote systems administration. Satellite Internet service costs limited the bandwidth to symmetrical 384 kbit/s. DICOM routers deployed at both the Malaŵi MRI facility and MSU manage the end-to-end encrypted compressed data transmission. Network performance between DICOM routers was measured while transmitting both mixed clinical MR studies and synthetic studies. Effective network latency averaged 715 ms. Within a mix of clinical MR studies, the average transmission time for a 256 × 256 image was ~2.25 and ~6.25 s for a 512 × 512 image. Using synthetic studies of 1,000 duplicate images, the interquartile range for 256 × 256 images was [2.30, 2.36] s and [5.94, 6.05] s for 512 × 512 images. Transmission of clinical MRI studies between the DICOM routers averaged 9.35 images per minute, representing an effective channel utilization of ~137% of the 384-kbit/s satellite service as computed using uncompressed image file sizes (including the effects of image compression, protocol overhead, channel latency, etc.). Power unreliability was the primary cause of interrupted operations in the first year, including an outage exceeding 10 days.


    Manning, R. M.


    The frequency and intensity of rain attenuation affecting the communication between a satellite and an earth terminal is an important consideration in planning satellite links. The NASA Lewis Research Center Satellite Link Attenuation Model Program (LeRC-SLAM) provides a static and dynamic statistical assessment of the impact of rain attenuation on a communications link established between an earth terminal and a geosynchronous satellite. The program is designed for use in the specification, design and assessment of satellite links for any terminal location in the continental United States. The basis for LeRC-SLAM is the ACTS Rain Attenuation Prediction Model, which uses a log-normal cumulative probability distribution to describe the random process of rain attenuation on satellite links. The derivation of the statistics for the rainrate process at the specified terminal location relies on long term rainfall records compiled by the U.S. Weather Service during time periods of up to 55 years in length. The theory of extreme value statistics is also utilized. The user provides 1) the longitudinal position of the satellite in geosynchronous orbit, 2) the geographical position of the earth terminal in terms of latitude and longitude, 3) the height above sea level of the terminal site, 4) the yearly average rainfall at the terminal site, and 5) the operating frequency of the communications link (within 1 to 1000 GHz, inclusive). Based on the yearly average rainfall at the terminal location, LeRC-SLAM calculates the relevant rain statistics for the site using an internal data base. The program then generates rain attenuation data for the satellite link. This data includes a description of the static (i.e., yearly) attenuation process, an evaluation of the cumulative probability distribution for attenuation effects, and an evaluation of the probability of fades below selected fade depths. In addition, LeRC-SLAM calculates the elevation and azimuth angles of the terminal


    Manning, R. M.


    The frequency and intensity of rain attenuation affecting the communication between a satellite and an earth terminal is an important consideration in planning satellite links. The NASA Lewis Research Center Satellite Link Attenuation Model Program (LeRC-SLAM) provides a static and dynamic statistical assessment of the impact of rain attenuation on a communications link established between an earth terminal and a geosynchronous satellite. The program is designed for use in the specification, design and assessment of satellite links for any terminal location in the continental United States. The basis for LeRC-SLAM is the ACTS Rain Attenuation Prediction Model, which uses a log-normal cumulative probability distribution to describe the random process of rain attenuation on satellite links. The derivation of the statistics for the rainrate process at the specified terminal location relies on long term rainfall records compiled by the U.S. Weather Service during time periods of up to 55 years in length. The theory of extreme value statistics is also utilized. The user provides 1) the longitudinal position of the satellite in geosynchronous orbit, 2) the geographical position of the earth terminal in terms of latitude and longitude, 3) the height above sea level of the terminal site, 4) the yearly average rainfall at the terminal site, and 5) the operating frequency of the communications link (within 1 to 1000 GHz, inclusive). Based on the yearly average rainfall at the terminal location, LeRC-SLAM calculates the relevant rain statistics for the site using an internal data base. The program then generates rain attenuation data for the satellite link. This data includes a description of the static (i.e., yearly) attenuation process, an evaluation of the cumulative probability distribution for attenuation effects, and an evaluation of the probability of fades below selected fade depths. In addition, LeRC-SLAM calculates the elevation and azimuth angles of the terminal

  16. Short-Term Prediction Research and Transition (SPoRT) Center: Transitioning Satellite Data to Operations

    Zavodsky, Bradley


    The Short-term Prediction Research and Transition (SPoRT) Center located at NASA Marshall Space Flight Center has been conducting testbed activities aimed at transitioning satellite products to National Weather Service operational end users for the last 10 years. SPoRT is a NASA/NOAA funded project that has set the bar for transition of products to operational end users through a paradigm of understanding forecast challenges and forecaster needs, displaying products in end users decision support systems, actively assessing the operational impact of these products, and improving products based on forecaster feedback. Aiming for quality partnerships rather than a large quantity of data users, SPoRT has become a community leader in training operational forecasters on the use of up-and-coming satellite data through the use of legacy instruments and proxy data. Traditionally, SPoRT has supplied satellite imagery and products from NASA instruments such as the Moderate-resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS). However, recently, SPoRT has been funded by the GOES-R and Joint Polar Satellite System (JPSS) Proving Grounds to accelerate the transition of selected imagery and products to help improve forecaster awareness of upcoming operational data from the Visible Infrared Imager Radiometer Suite (VIIRS), Cross-track Infrared Sounder (CrIS), Advanced Baseline Imager (ABI), and Geostationary Lightning Mapper (GLM). This presentation provides background on the SPoRT Center, the SPoRT paradigm, and some example products that SPoRT is excited to work with forecasters to evaluate.

  17. Variable conductance heat pipe technology. [research project resulting in heat pipe experiment on OAO-3 satellite

    Anderson, W. T.; Edwards, D. K.; Eninger, J. E.; Marcus, B. D.


    A research and development program in variable conductance heat pipe technology is reported. The project involved: (1) theoretical and/or experimental studies in hydrostatics, (2) hydrodynamics, (3) heat transfer into and out of the pipe, (4) fluid selection, and (5) materials compatibility. The development, fabrication, and test of the space hardware resulted in a successful flight of the heat pipe experiment on the OAO-3 satellite. A summary of the program is provided and a guide to the location of publications on the project is included.

  18. The evolution of ozone observed by UARS MLS in the 1992 late winter southern polar vortex

    Manney, G.L.; Froidevaux, L.; Waters, J.W.; Elson, L.S.; Fishbein, E.F.; Zurek, R.W. (California Institute of Technology, Pasadena (United States)); Harwood, R.S.; Lahoz, W.A. (Edinburgh Univ. (United Kingdom))


    This paper presents initial data analysis of ozone distributions in the southern polar vortex region during the winter of 1992. The data comes from the microwave limb sounder on the upper atmosphere research satellite. The data provides never before available coverage of the polar stratosphere, and reveals the development of an ozone hole from column ozone data, changes in ozone mixing ratios in the lower stratosphere consistent with ozone destruction processes in the stratosphere, and evidence to support the transport of ozone toward the pole by tidal wave activity in the stratosphere. The ozone measurements are compared with the development of the polar vortex derived from national meteorological center data.

  19. Research on Satellite Fault Diagnosis and Prediction Using Multi-modal Reasoning

    YangTianshe; SunYanhong; CaoYuping


    Diagnosis and prediction of satellite fault are more difficult than that of other equipment due to the complex structure of satellites and the presence of muhi-excite sources of satellite faults. Generally, one kind of reasoning model can only diagnose and predict one kind of satellite faults. In this paper the author introduces an application of a new method using multi-modal reasoning to diagnose and predict satellite faults. The method has been used in the development of knowledge-based satellite fault diagnosis and recovery system (KSFDRS) successfully. It is shown that the method is effective.

  20. The Ørsted Satellite in the International Decade of Geopotential Field Research (Petrus Peregrinus Medal Lecture)

    Friis-Christensen, E.


    The launch of the Danish satellite Ørsted on 23 February, 1999 marked the beginning of the "Decade of Geopotential Field Research", an international effort to promote and coordinate a continuous monitoring of the geopotential (magnetic and gravity) field variability in the near-Earth environment. Already the first years of Ørsted magnetic field observations showed that dramatic changes had taken place, in particular in the South Atlantic / South African continent during the 20 years that had elapsed without satellite data after the NASA MAGSAT satellite mapping of the Earth's magnetic field. Although only designed with a life time of 14 months, the Ørsted satellite has still been providing valuable data, 10 years after launch, and has during this time been accompanied by two other geomagnetic satellite missions, the German CHAMP and the Argentinean SAC-C, both with similar instrumentation as the Ørsted satellite. This long period of continuous satellite observations of the magnetic field brought a number of scientific results including the detection of rapidly changing flows at the top of the core and crucial contribution to the derivation of the first World Digital Magnetic Anomaly Map. Furthermore, the high quality of the observations made it possible to identify completely new satellite magnetic signatures related to oceanic tides, ionospheric pressure gradient currents, and magnetic signatures of plasma bubbles. As often in science, new observations trigger new questions, which need to be answered with even more sophisticated measurements. This challenge was taken up by ESA by its selection of Swarm as the 5th mission in the Earth Explorer Programme. The three satellite constellation mission Swarm will be launched in 2010-11 with the objective to provide the best ever survey of the geomagnetic field and its temporal evolution in order to improve our understanding of the Earth's interior and the Geospace environment including the Sun-Earth connection

  1. The Design of Compass/BeiDou Navigation Satellite Terminal for Migrant Bird Research

    Yaohui Li


    Full Text Available A terminal of Compass Navigation Satellite System (CNSS, which can not only support BeiDou-1 and BeiDou-2 but also support Global Positioning System (GPS, is designed to research the activities of the migrant birds, with our novel design of a multiband antenna. By a high-density integration, this terminal is designed with a compact size and light weight. When the terminal is assembled to a whooper swan, its flying trace is recorded by the CNSS, which is in agreement with that of GPS. The flying route map based on the CNSS is useful to check the situation and habit of the migrant bird, which is important for animal protection and bird flu outbreak prediction.

  2. Rainfall variability over southern Africa: an overview of current research using satellite and climate model data

    Williams, C.; Kniveton, D.; Layberry, R.


    It is increasingly accepted that any possible climate change will not only have an influence on mean climate but may also significantly alter climatic variability. A change in the distribution and magnitude of extreme rainfall events (associated with changing variability), such as droughts or flooding, may have a far greater impact on human and natural systems than a changing mean. This issue is of particular importance for environmentally vulnerable regions such as southern Africa. The subcontinent is considered especially vulnerable to and ill-equipped (in terms of adaptation) for extreme events, due to a number of factors including extensive poverty, famine, disease and political instability. Rainfall variability is a function of scale, so high spatial and temporal resolution data are preferred to identify extreme events and accurately predict future variability. In this research, satellite-derived rainfall data are used as a basis for undertaking model experiments using a state-of-the-art climate model, run at both high and low spatial resolution. Once the model's ability to reproduce extremes has been assessed, idealised regions of sea surface temperature (SST) anomalies are used to force the model, with the overall aim of investigating the ways in which SST anomalies influence rainfall extremes over southern Africa. In this paper, a brief overview is given of the authors' research to date, pertaining to southern African rainfall. This covers (i) a description of present-day rainfall variability over southern Africa; (ii) a comparison of model simulated daily rainfall with the satellite-derived dataset; (iii) results from sensitivity testing of the model's domain size; and (iv) results from the idealised SST experiments.

  3. Promoting space research and applications in developing countries through small satellite missions

    Sweeting, M.

    The high vantage-point of space offers very direct and tangible benefits to developing countries when carefully focused upon their real and particular communications and Earth observation needs. However, until recently, access to space has been effectively restricted to only those countries prepared to invest enormous sums in complex facilities and expensive satellites and launchers: this has placed individual participation in space beyond the sensible grasp of developing countries. However, during the last decade, highly capable and yet inexpensive small satellites have been developed which provide an opportunity for developing countries realistically to acquire and operate their own independent space assets - customized to their particular national needs. Over the last 22 years, the Surrey Space Centre has pioneered, developed and launched 23 nano-micro-minisatellite missions, and has worked in partnership with 12 developing countries to enable them to take their first independent steps into space. Surrey has developed a comprehensive and in-depth space technology know-how transfer and 'hands-on' training programme that uses a collaborative project comprising the design, construction, launch and operation of a microsatellite to acquire an indigenous space capability and create the nucleus of a national space agency and space industry. Using low cost small satellite projects as a focus, developing countries are able to initiate a long term, affordable and sustainable national space programme specifically tailored to their requirements, that is able to access the benefits derived from Earth observation for land use and national security; improved communications services; catalyzing scientific research and indigenous high-technology supporting industries. Perhaps even more important is the long-term benefit to the country provided by stimulating educational and career opportunities for your scientists and engineers and retaining them inside the country rather the

  4. Longitudinal structure in atomic oxygen concentrations observed with WINDII on UARS. [Wind Imaging Interferometer

    Shepherd, G. G.; Thuillier, G.; Solheim, B. H.; Chandra, S.; Cogger, L. L.; Duboin, M. L.; Evans, W. F. J.; Gattinger, R. L.; Gault, W. A.; Herse, M.


    WINDII, the Wind Imaging Interferometer on the Upper Atmosphere Research Satellite, began atmospheric observations on September 28, 1991 and since then has been collecting data on winds, temperatures and emissions rates from atomic, molecular and ionized oxygen species, as well as hydroxyl. The validation of winds and temperatures is not yet complete, and scientific interpretation has barely begun, but the dominant characteristic of these data so far is the remarkable structure in the emission rate from the excited species produced by the recombination of atomic oxygen. The latitudinal and temporal variability has been noted before by many others. In this preliminary report on WINDII results we draw attention to the dramatic longitudinal variations of planetary wave character in atomic oxygen concentration, as reflected in the OI 557.7 nm emission, and to similar variations seen in the Meine1 hydroxyl band emission.

  5. Supporting a Diverse Community of Undergraduate Researchers in Satellite and Ground-Based Remote Sensing

    Blake, R.; Liou-Mark, J.


    The U.S. remains in grave danger of losing its global competitive edge in STEM. To find solutions to this problem, the Obama Administration proposed two new national initiatives: the Educate to Innovate Initiative and the $100 million government/private industry initiative to train 100,000 STEM teachers and graduate 1 million additional STEM students over the next decade. To assist in ameliorating the national STEM plight, the New York City College of Technology has designed its NSF Research Experience for Undergraduate (REU) program in satellite and ground-based remote sensing to target underrepresented minority students. Since the inception of the program in 2008, a total of 45 undergraduate students of which 38 (84%) are considered underrepresented minorities in STEM have finished or are continuing with their research or are pursuing their STEM endeavors. The program is comprised of the three primary components. The first component, Structured Learning Environments: Preparation and Mentorship, provides the REU Scholars with the skill sets necessary for proficiency in satellite and ground-based remote sensing research. The students are offered mini-courses in Geographic Information Systems, MATLAB, and Remote Sensing. They also participate in workshops on the Ethics of Research. Each REU student is a member of a team that consists of faculty mentors, post doctorate/graduate students, and high school students. The second component, Student Support and Safety Nets, provides undergraduates a learning environment that supports them in becoming successful researchers. Special networking and Brown Bag sessions, and an annual picnic with research scientists are organized so that REU Scholars are provided with opportunities to expand their professional community. Graduate school support is provided by offering free Graduate Record Examination preparation courses and workshops on the graduate school application process. Additionally, students are supported by college

  6. A research feasibility study proposal for conducting experimental research in curriculum sharing via Communications Technology Satellite among institutions having large minority enrollments

    Williams, L., Jr.


    The applicability of the tele-conference method of curriculum sharing as well as the sharing of scientific research results between universities and industrial organizations was evaluated in relation to other techniques and methods. Ten universities cooperated with NC A&T State University in an effort to increase the number of minority scientists and engineers in the USA via the utilization of the communication features of satellites. Research activities, experiments and studies in curriculum sharing are described as well as the techniques, interconnections and equipment utilized. Suggested methods and recommendations for a continuation of innovative applications of satellite technology in higher education at NC A&T State University are included.

  7. Satellite Data Support for the ARM Climate Research Facility, 8/01/2009 - 7/31/2015

    Minnis, Patrick [NASA Langley Research Center, Hampton, VA (United States); Khaiyer, Mandana M [Science Systems and Applications, Inc., Hampton, VA (United States)


    This report summarizes the support provided by NASA Langley Research for the DOE ARM Program in the form of cloud and radiation products derived from satellite imager data for the period between 8/01/09 through 7/31/15. Cloud properties such as cloud amount, height, and optical depth as well as outgoing longwave and shortwave broadband radiative fluxes were derived from geostationary and low-earth orbiting satellite imager radiance measurements for domains encompassing ARM permanent sites and field campaigns during the performance period. Datasets provided and documents produced are listed.




    This is a summarized paper.Two topics are discussed:Firstly,the comcept,development and application of four kinds of satellite gravity surveying technology are introduced;Secondly,some problems of theory and method,which must be considered in the study lf the Earth's gravity field based on satellite gravity data,are expounded.

  9. Research on HJ-1A/B satellite data automatic geometric precision correction design

    Xiong Wencheng; Shen Wenming; Wang Qiao; Shi Yuanli; Xiao Rulin; Fu Zhuo


    Developed independently by China,HJ-1A/B satellites have operated well on-orbit for five years and acquired a large number of high-quality observation data. The realization of the observation data geometric precision correction is of great significance for macro and dynamic ecological environment monitoring. The pa-per analyzed the parameter characteristics of HJ-1 satellite and geometric features of HJ-1 satellite level 2 data (systematic geo-corrected data). Based on this,the overall HJ-1 multi-sensor geometric correction flow and charge-coupled device (CCD) automatic geometric precision correction method were designed. Actual operating data showed that the method could achieve good result for automatic geometric precision correction of HJ-1 sat-ellite data,automatic HJ-1 CCD image geometric precision correction accuracy could be achieved within two pixels and automatic matching accuracy between the images of same satellite could be obtained less than one pixel.

  10. Quest for learning: A study of teachers' perceptions of the Satellite Education and Environmental Research Program

    Ahern, Kathryn A.

    The purpose of this study was to examine the perceptions of teachers who participated in the Satellite Education and Environmental Research (SEER) Program Water Project, a curriculum design course developed at the University of Nebraska-Lincoln. The distance education course was a complex intervention which used the Nebraska Mathematics and Science Initiative's Model Program criteria for inquiry-based curriculum. Teachers formed communities of inquiry, experienced scientific inquiry processes, integrated different disciplines to create new thematic science curricula, and were encouraged to employ innovative pedagogical practices. National Science Education Standards and Nebraska Mathematics and Science Frameworks were consulted to develop important science process skills and concepts. Multicultural science education was addressed through investigation of local water issues. Teachers were encouraged to form community partnerships, supported with testing materials for conducting scientific research, and expected to use computer technology. Grounded theory was used to examine interviews of 26 participants for their perceptions of the effects of the intervention on their teaching strategies. The self-reports were triangulated through the external evaluation report, classroom artifacts, and a limited number of observations of classroom and field activities. Open coding was used to categorize the interview responses and to propose relationships among them. The central phenomenon that emerged from the axial and select coding was the changed focus: teaching science more thematically. Three theoretical propositions were posed to guide further inquiry: (1) teachers need opportunities and resources to experience science as an authentic, tenable, and realistic process if they are to develop curriculum and focus classroom activities on scientific inquiry; (2) autonomous learning communities must be fostered at downlink sites if distance learning experiences are to affect

  11. MarsCAT: Mars Array of ionospheric Research Satellites using the CubeSat Ambipolar Thruster

    Bering, E. A., III; Pinsky, L.; Li, L.; Jackson, D. R.; Chen, J.; Reed, H.; Moldwin, M.; Kasper, J. C.; Sheehan, J. P.; Forbes, J.; Heine, T.; Case, A. W.; Stevens, M. L.; Sibeck, D. G.


    The MarsCAT (Mars Array of ionospheric Research Satellites using the CubeSat Ambipolar Thruster) Mission is a two 6U CubeSat mission to study the ionosphere of Mars proposed for the NASA SIMPLeX opportunity. The mission will investigate the plasma and magnetic structure of the Martian ionosphere, including transient plasma structures, magnetic field structure and dynamics, and energetic particle activity. The transit plan calls for a piggy back ride with Mars 2020 using a CAT burn for MOI, the first demonstration of CubeSat propulsion for interplanetary travel. MarsCAT will make correlated multipoint studies of the ionosphere and magnetic field of Mars. Specifically, the two spacecraft will make in situ observations of the plasma density, temperature, and convection in the ionosphere of Mars. They will also make total electron content measurements along the line of sight between the two spacecraft and simultaneous 3-axis local magnetic field measurements in two locations. Additionally, MarsCAT will demonstrate the performance of new CubeSat telemetry antennas designed at the University of Houston that are designed to be low profile, rugged, and with a higher gain than conventional monopole (whip) antennas. The two MarsCAT CubeSats will have five science instruments: a 3-axis DC magnetometer, adouble-Langmuir probe, a Faraday cup, a solid state energetic particle detector (Science Enhancement Option), and interspacecraft total electron content radio occulation experiment. The MarsCAT spacecraft will be solar powered and equipped with a CAT thruster that can provide up to 4.8 km/s of delta-V, which is sufficient to achieve Mars orbit using the Mars 2020 piggyback. They have an active attitude control system, using a sun sensor and flight-proven star tracker for determination, and momentum wheels for 3-axis attitude control.

  12. Spatio-temporal variability of the polar middle atmosphere. Insights from over 30 years of research satellite observations

    Lahoz, W.A.; Orsolini, Y.J.; Manney, G.L.; Minschwaner, K.; Allen, D.R.; Errera, Q.; Jackson, D.R.; Lambert, A.; Lee, J.; Pumphrey, H.; Schwartz, M.; Wu, D.


    We discuss the insights that research satellite observations from the last 30 years have provided on the spatio-temporal variability of the polar middle atmosphere. Starting from the time of the NASA LIMS (Limb Infrared Monitor of the Stratosphere) and TOMS (Total Ozone Mapping Spectrometer) instruments, both launched in 1978, we show how these observations have augmented our knowledge of the polar middle atmosphere, in particular how information on ozone and tracers has augmented our knowledge of: (i) the spatial and temporal characteristics of the wintertime polar stratosphere and the summertime circulation; and (ii) the roles of chemistry and transport in determining the stratospheric ozone distribution. We address the increasing joint use of observations and models, in particular in data assimilation, in contributing to this understanding. Finally, we outline requirements to allow continuation of the wealth of information on the polar middle atmosphere provided by research satellites over the last 30 years.(Author)

  13. Global mesospheric tidal winds observed by the high resolution Doppler imager on board the upper atmosphere research satellite

    Morton, Y.T.; Lieberman, R.S.; Hays, P.B.; Ortland, D.A.; Marshall, A.R.; Wu, D.; Skinner, W.R.; Burrage, M.D.; Gell, D.A.; Yee, J.H.


    This paper presents results of mesospheric and lower thermospheric wind tides. The observations come from the high resolution doppler imager (HRDI) on board the upper atmosphere research satellite. From these observations, the authors report the observation of tidal effects on top of the meridonal winds observed in this region. Previous measurements have been mainly limited to radar measurements from fixed ground stations, which do not give consistent results, and do not provide a global picture of the wave structure.

  14. Research on GPS Receiver Autonomous Integrity Monitoring Algorithm In the Occurrence of Two-satellite Faults

    Wang Er Shen


    Full Text Available Reliability is an essential factor for GPS navigation system. Therefore, an integrity monitoring is considered as one of the most important parts for a navigation system. GPS receiver autonomous integrity monitoring (RAIM technique can detect and isolate fault satellite. Based on particle filter, a novel RAIM method was proposed to detect two-satellite faults of the GPS signal by using hierarchical particle filter. It can deal with any system nonlinear and any noise distributions. Because GNSS measurement noise does not follow the Gaussian distribution perfectly, the particle filter can estimate the posterior distribution more accurately. In order to detect fault, the consistency test statistics is established through cumulative log-likelihood ratio (LLR between the main and auxiliary particle filters (PFs.Specifically, an approach combining PF with the hierarchical filter is used in the process of two-satellite faults. Through GPS real measurement, the performance of the proposed GPS two-satellite faults detection algorithm was illustrated. Some simulation results are given to evaluate integrity monitoring performance of the algorithm. Validated by the real measurement data, the results show that the proposed algorithm can successfully detect and isolate the faulty satellite in the case of non-Gaussian measurement noise.

  15. Research on the new type of multi-functional satellite system for space debris detection

    Guo, Linghua; Fu, Qiang; Jiang, Huilin; Xu, Xihe


    With the rapid development of space exploration and utilization, orbital debris increases dramatically, leading to great threat to human space activities and spacecraft security. In this paper, a new type of multi-functional space debris satellite system (MSDS) was put forward, which shared main optical system, and possessed functions of multidimensional information detection, polarized remote sensing and high rate transmission. The MSDS system can meet the requirements of detection and identification for the small orbital debris which is 1000km faraway, as well as the requirements of the data transmission by 50 Mbps to 2.5 Gbps@200-1000 km. At the same time, by the method of satellite orbital maneuver and attitude adjusting, the orbital debris information that is real-time, complex and refined, allweather can be acquired and transmitted by the new system. Such new type of multifunctional satellite system can provide important and effective technology for international orbital debris detection.


    T. D. Tran


    Full Text Available The study area is bordered on the East China Sea, the Philippine Sea, and the Australian-Indo plate in the Northeast, in the East and in the South, respectively. It is a large area with the diversely complicated conditions of geological structure. In spite of over the past many years of investigation, marine geological structure in many places have remained poorly understood because of a thick seawater layer as well as of the sensitive conflicts among the countries in the region. In recent years, the satellite altimeter technology allows of enhancement the marine investigation in any area. The ocean surface height is measured by a very accurate radar altimeter mounted on a satellite. Then, that surface can be converted into marine gravity anomaly or bathymetry by using the mathematical model. It is the only way to achieve the data with a uniform resolution in acceptable time and cost. The satellite altimetry data and its variants are essential for understanding marine geological structure. They provide a reliable opportunity to geologists and geophysicists for studying the geological features beneath the ocean floor. Also satellite altimeter data is perfect for planning the more detailed shipboard surveys. Especially, it is more meaningful in the remote or sparsely surveyed regions. In this paper, the authors have effectively used the satellite altimetry and shipboard data in combination. Many geological features, such as seafloor spreading ridges, fault systems, volcanic chains as well as distribution of sedimentary basins are revealed through the 2D, 3D model methods of interpretation of satellite-shipboard-derived data and the others. These results are improved by existing boreholes and seismic data in the study area.

  17. Contribution of Satellite Altimetry Data in Geological Structure Research in the South China Sea

    Dung Tran, Tuan; Ho, Thi Huong Mai


    The study area is bordered on the East China Sea, the Philippine Sea, and the Australian-Indo plate in the Northeast, in the East and in the South, respectively. It is a large area with the diversely complicated conditions of geological structure. In spite of over the past many years of investigation, marine geological structure in many places have remained poorly understood because of a thick seawater layer as well as of the sensitive conflicts among the countries in the region. In recent years, the satellite altimeter technology allows of enhancement the marine investigation in any area. The ocean surface height is measured by a very accurate radar altimeter mounted on a satellite. Then, that surface can be converted into marine gravity anomaly or bathymetry by using the mathematical model. It is the only way to achieve the data with a uniform resolution in acceptable time and cost. The satellite altimetry data and its variants are essential for understanding marine geological structure. They provide a reliable opportunity to geologists and geophysicists for studying the geological features beneath the ocean floor. Also satellite altimeter data is perfect for planning the more detailed shipboard surveys. Especially, it is more meaningful in the remote or sparsely surveyed regions. In this paper, the authors have effectively used the satellite altimetry and shipboard data in combination. Many geological features, such as seafloor spreading ridges, fault systems, volcanic chains as well as distribution of sedimentary basins are revealed through the 2D, 3D model methods of interpretation of satellite-shipboard-derived data and the others. These results are improved by existing boreholes and seismic data in the study area.

  18. Research of Multi-Agent System based satellite fault diagnosis technology

    范显峰; 姜兴渭; 黄文虎; 谷吉海


    Following the theory of Multi-Agent System (MAS) and using series-wound structure and shunt-wound structure of Agents, the performance of Agent was improved to satisfy the need of satellite fault diagno-sis, and a tridimensional MAS model of satellite fault diagnosis was thus established for the MAS based planardiagnosis system, which decentralizes the whole diagnosing task into subtasks to be performed by different func-tional Agents to make the complicated fault diagnosis very simple and the diagnosis system more intelligent.This method improved the reliability and accuracy of diagnosis and made the maintenance and upgrading of thesatellite fault diagnosis system very easy as well.

  19. Research on handover algorithm to reduce the blocking probability in LEO satellite network

    Chen Bingcai; Zhang Naitong; Nie Boxun; Zhou Tingxian


    Based on the characteristics of guaranteed handover (GH) algorithm, the finite capacity in one system makes the blocking probability (PB) of GH algorithm increase rapidly in the case of high traffic load. So, when large amounts of multimedia services are transmitted via a single low earth orbit (LEO) satellite system, the PB of it is much higher. In order to solve the problem, a novel handover scheme defined by multi-tier optiral layer selection is proposed. The scheme sufficienfly takes into ac count the characteristics of double-tier satellite network, which is constituted by LEO satellites combined with medium earth orbit (MEO) satellites, and the multimedia transmitted by such network, so it can augment this systematic capacity and effectively reduces the traffic load in the LEO which performs GH algorithm. The detailed processes are also presented. The simulation and numerical results show that the approach integrated with GH algorithm achieves a significant improvement in the PB and practicability, as compared to the single LEO layer network.

  20. Report of survey research of ways of using second generation practical broadcasting satellites


    The state of development of satellite broadcasting in Japan, was determined was determined and recommendations were made regarding what organizations would use it and what kind of results could be forthcoming. The primary use at this stage is for television broadcasting, and the secondary use is for testing new broadcasting methods and for use by Japan's new Broadcasting University.

  1. Assimilation of microwave, infrared, and radio occultation satellite observations with a weather research and forecasting model for heavy rainfall forecasting

    Boonyuen, Pakornpop; Wu, Falin; Phunthirawuth, Parwapath; Zhao, Yan


    In this research, satellite observation data were assimilated into Weather Research and Forecasting Model (WRF) by using Three-dimensional Variational Data Assimilation System (3DVAR) to analyze its impacts on heavy rainfall forecasts. The weather case for this research was during 13-18 September 2015. Tropical cyclone VAMCO, forming in South China Sea near with Vietnam, moved on west direction to the Northeast of Thailand. After passed through Vietnam, the tropical cyclone was become to depression and there was heavy rainfall throughout the area of Thailand. Observation data, used in this research, included microwave radiance observations from the Advanced Microwave Sounding Unit-A (AMSU-A), infrared radiance observations from Infrared Atmospheric Sounding Interferometer (IASI), and GPS radio occultation (RO) from the COSMIC and CHAMP missions. The experiments were designed in five cases, namely, 1) without data assimilation (CTRL); 2) with only RO data (RO); 3) with only AMSU-A data (AMSUA); 4) with only IASI data (IASI); and 5) with all of RO, AMSU-A and IASI data assimilation (ALL). Then all experiment results would be compared with both NCEP FNL (Final) Operational Global Analysis and the observation data from Thai Meteorological Department weather stations. The experiments result demonstrated that with microwave (AMSU-A), infrared (IASI) and GPS radio occultation (RO) data assimilation can produce the positive impact on analyses and forecast. All of satellite data assimilations have corresponding positive effects in term of temperature and humidity forecasting, and the GPS-RO assimilation produces the best of temperature and humidity forecast biases. The satellite data assimilation has a good impact on temperature and humidity in lower troposphere and vertical distribution that very helpful for heavy rainfall forecast improvement.

  2. Nonlinear compensation research and simulation of bandlimited QPSK digital satellite channels


    Presents a phase compensation against the signal distortion mainly caused by TWTA to solve the problem of compensation and modelling of a nonlinear QPSK satellite channel assumed to be bandlimited and exhibit both ampli tude and phase nonlinearities, and to lower the bit error probability of nonlinear channel, and concludes with simula tion results that the compensation against phase distortion of TWTA can significantly improve the nonlinear performance of the channel.

  3. Precipitation Analysis at Fine Time Scales Using Multiple Satellites: Real-time and Research Products and Applications

    Adler, Robert; Huffman, George; Bolvin, David; Nelkin, Eric; Curtis, Scott; Pierce, Harold


    Quasi-global precipitation analyses at fine time scales (3-hr) are described. TRMM observations (radar and passive microwave) are used to calibrate polar-orbit microwave observations from SSM/I (and other satellites instruments, including AMSR and AMSU) and geosynchronous IR observations. The individual data sets are then merged using a priority order based on quality to form the Multi-satellite Precipitation Analysis (MPA). Raingauge information is used to help constrain the satellite-based estimates over land. The TRMM standard research product (Version 6 3B-42 of the TRMM products) will be available for the entire TRMM period (January 1998-present) in 2004. The real-time version of this merged product has been produced over the past two years and is available on the U.S. TRMM web site ( at 0.25" latitude-longitude resolution over the latitude range from 5O"N-5O0S. Validation of daily totals indicates good results, with limitations noted in mid-latitude winter over land and regions of shallow, orographic precipitation. Various applications of these estimates are described, including: 1) detecting potential floods in near real-time; 2) analyzing Indian Ocean precipitation variations related to the initiation of El Nino; 3) determining characteristics of the African monsoon; and 4) analysis of diurnal variations.

  4. Precipitation Analysis at Fine Time Scales using TRMM and Other Satellites: Real-time and Research Products and Applications

    Adler, Robert; Huffman, George; Bolvin, David; Nelkin, Eric; Curtis, Scott; Pierce, Harold; Gu, Guo-Jon


    Quasi-global precipitation analyses at fine time scales (3-hr) are described. TRMM observations (radar and passive microwave) are used to calibrate polar-orbit microwave observations from SSM/I (and other satellites instruments, including AMSR and AMSU) and geosynchronous IR observations. The individual data sets are then merged using a priority order based on quality to form the TRMM Multi-satellite Precipitation Analysis (MPA). Raingauge information is used to help constrain the satellite-based estimates over land. The TRMM standard research product (Version 6 3B-42 of the TRMM products) will be available for the entire TRMM period (January 1998-present) by the end of 2004. The real-time version of this merged product has been produced over the past two years and is available on the U.S. TRMM web site ( at 0.25" latitude-longitude resolution over the latitude range from 5O0N-50"S. Validation of daily totals indicates good results, with limitations noted in mid-latitude winter over land and regions of shallow, orographic precipitation. Various applications of these estimates are described, includmg: 1) detecting potential floods in near real-time; 2) analyzing Indian Ocean precipitation variations related to the initiation of El Nino; 3) determining characteristics of the African monsoon; and 4) analysis of diurnal variations.

  5. Application of MODIS satellite products to the air pollution research in Beijing

    LI; Chengcai; MAO; Jietai; Alexis; K.; H.; Lau; YUAN; Zibin


    The direct correlation between NASA MODIS aerosol optical depth (AOD) products and the air pollution index (API) in Beijing was found relatively low based on the long-term comparison analysis. The correlation improved to some extent after taking account of the seasonal variation of scale height and the vertical distribution of aerosols. The correlation coefficient further improved significantly after considering the influencing factor of Relative Humidity (RH). This study concluded that satellite remote-sensing could serve as an efficient tool for monitoring the spatial distribution of particulate pollutants on the ground-level, as long as corrections have been made in the two aforementioned processes. Taking advantage of the MODIS information, we analyzed a pollution episode occurring in October 2004 in Beijing. It indicated that satellite remote-sensing could describe the formation process of the ground-level pollution episode in detail, and showed that regional transport and the topography were crucial factors to air quality in Beijing. The annual averaged distribution in the urban area of Beijing and its surroundings could be also obtained from the high-resolution retrieval results, implicating that high-resolution satellite remote-sensing might be potential in monitoring the source distribution of particulate pollutants.

  6. Role of Indian remote sensing imaging satellites for the Antarctic monitoring and mapping: a case study around Indian Antarctic research stations

    Jayaprasad, P.; Mehra, Raghav; Chawla, Saket; Rajak, D. Ram; Oza, Sandip R.


    Antarctic research station's existence largely depend on the supply of fuel, food and other commodities through Antarctic Scientific Expedition using ship voyage. Safer Ship Navigation demands high resolution satellite monitoring of the ice conditions which varies from 30 km to 200 km from the Antarctic coast of Research stations. During the last couple of years Indian Satellites play a major role in safer ship navigation in sea ice regions of the Arctic and the Antarctic. Specifically Indian Scientific Expedition to the Antarctica (ISEA) through National Centre for Antarctic and Oceanic Research (NCAOR) is one of the beneficiaries for safer ship navigation using information derived from Indian Satellite data. Space Applications Centre, Indian Space Research Organisation (SAC-ISRO) is providing Sea Ice Advisories for the safer optimum entry and exit for the expedition ship at two of the Research stations Bharati and Maitri. Two of the Indian Satellites namely Radar Imaging Satellite-1 (RISAT-1) and ResourceSAT-2 (RS-2) are the two major workhorses of ISRO for monitoring and mapping of the Antarctic terrain. The present study demonstrate the utilisation potential of these satellite images for various Polar Science Applications. Mosaic of the Antarctic Terrain was generated from RISAT-1 CRS data. The preliminary results of the mosaic from CRS- circular polarisation data is presented. Demonstration of the study is extended for other applications such as change detection studies, safer ship navigation and extreme events of Antarctica. The use of multi resolution multi sensor data is also shown in the study.

  7. The Swarm Satellite Constellation Application and Research Facility (SCARF) and Swarm data products

    Olsen, Nils; Friis-Christensen, Eigil; Floberghagen, R.


    Swarm, a three-satellite constellation to study the dynamics of the Earth's magnetic field and its interactions with the Earth system, is expected to be launched in late 2013. The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal evolution......, in order to gain new insights into the Earth system by improving our understanding of the Earth's interior and environment. In order to derive advanced models of the geomagnetic field (and other higher-level data products) it is necessary to take explicit advantage of the constellation aspect of Swarm...

  8. Stratospheric effects of 27-day solar ultraviolet variations: An analysis of UARS MLS ozone and temperature data

    Hood, L. L.; Zhou, S.


    The characteristics of upper stratospheric ozone and temperature responses at low latitudes to short-term solar ultraviolet variations are studied by using 1000 days of UARS microwave limb sounder (MLS) and solar stellar irradiance comparison experiment data. Consistent with previous analyses of Nimbus 7 solar backscattered ultraviolet (SBUV) data, the high-pass-filtered solar flux in the 200-to 205-nm interval is most strongly correlated with MLS ozone measurements at tropical latitudes near 4 hPa with a sensitivity of about 0.4% for each 1% change in the solar flux. Reproducibility tests, power spectral, and coherency estimates support the reality of the observed ozone response at this level. The MLS solar UV/ozone response is significantly reduced at levels above ~2hPa as compared to earlier results based on SBUV data. This reduction appears to be a consequence of the ozone diurnal cycle at high altitudes combined with the necessary inclusion of nighttime records in calculating the MLS ozone zonal averages. Some evidence is obtained for an MLS solar UV/temperature response near the stratopause, but coherency tests are negative. Future analyses of independent data records having similar local time coverage as that of Nimbus 7 SBUV are needed to establish more definitively whether any significant change in the upper stratospheric UV response has occurred.

  9. Global distributions of diurnal and semi-diurnal tides: observations from HRDI-UARS of the MLT region

    A. H. Manson

    Full Text Available HRDI (High Resolution Doppler Interferometer-UARS winds data have been analyzed in 4° latitude by 10° longitude cells at 96 km to obtain global contour maps of solar-tidal amplitudes and phases, and also mean winds. The solstices June–July (1993, December–January (1993–1994, and one equinox September–October (1994 are shown. 

    The 24-h diurnal tide that maximizes near the 20–25° latitude has significant seasonal changes with equinoctial maxima, and very clear longitudinal variability. Maxima are very clear over the oceans. In contrast, the 12-h semi-diurnal tides that maximize near the 40–55° latitude have very strong seasonal changes with winter maxima, and more modest longitudinal changes. The similarities with MLT (mesosphere-lower thermosphere radar observations (90 km and the GSWM (Global Scale Wave Model are very satisfactory. The mean winds are consistent with expectations and show clear poleward flow from summer to winter hemispheres in the solstices.

    Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides Radio science (remote sensing

  10. Satellite Cloud Assimilation in the Weather Research & Forecasting (WRF) Model and its Impact on Air Quality Simulations

    Pour Biazar, Arastoo; White, Andrew; McNider, Richard; Khan, Maudood; Dornblaser, Bright; Wu, Yuling


    Clouds have a significant role in air quality simulations as they modulate biogenic hydrocarbon emissions and photolysis rates, impact boundary-layer development, lead to deep vertical mixing of pollutants and precursors, and induce aqueous phase chemistry. Unfortunately, numerical meteorological models still have difficulty in creating clouds in the right place and time compared to observed clouds. This is especially the case when synoptic-scale forcing is weak, as often is the case during air pollution episodes in the Southeast United States. Thus, poor representation of clouds impacts the photochemical model's ability in simulating the air quality. However, since satellites provide the best observational platform for defining the formation and location of clouds, satellite observations can be of great value in retrospective simulations. Here, we present results from a recent activity in which the Geostationary Operational Environmental Satellite (GOES) derived cloud fields are assimilated within Weather Research and Forecasting (WRF) model to improve simulated clouds. The assimilation technique dynamically support cloud formation/dissipation within WRF based on GOES observations. The technique uses observations to identify model cloud errors, estimates a target vertical velocity and moisture to create/remove clouds, and adjust the flow field accordingly. The technique was implemented and tested in WRF for a month-long simulation during August 2006, and was tested in an air quality simulation over the period of August-September 2013 (NASA's Discover-AQ field campaign). The cloud assimilation on the average improved model cloud simulation by 15%. The cloud correction not only improved the spatial and temporal distribution of clouds, it also improved boundary layer temperature, humidity, and wind speed. These improvements in meteorological fields directly impacted the air quality simulations and altered trace gas concentrations. For air quality simulations, WRF

  11. The Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS mission: design, execution, and first results

    D. J. Jacob


    Full Text Available The NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS mission was conducted in two 3-week deployments based in Alaska (April 2008 and western Canada (June–July 2008. Its goal was to better understand the factors driving current changes in Arctic atmospheric composition and climate, including (1 influx of mid-latitude pollution, (2 boreal forest fires, (3 aerosol radiative forcing, and (4 chemical processes. The June–July deployment was preceded by one week of flights over California (ARCTAS-CARB focused on (1 improving state emission inventories for greenhouse gases and aerosols, (2 providing observations to test and improve models of ozone and aerosol pollution. ARCTAS involved three aircraft: a DC-8 with a detailed chemical payload, a P-3 with an extensive aerosol and radiometric payload, and a B-200 with aerosol remote sensing instrumentation. The aircraft data augmented satellite observations of Arctic atmospheric composition, in particular from the NASA A-Train. The spring phase (ARCTAS-A revealed pervasive Asian pollution throughout the Arctic as well as significant European pollution below 2 km. Unusually large Siberian fires in April 2008 caused high concentrations of carbonaceous aerosols and also affected ozone. Satellite observations of BrO column hotspots were found not to be related to Arctic boundary layer events but instead to tropopause depressions, suggesting the presence of elevated inorganic bromine (5–10 pptv in the lower stratosphere. Fresh fire plumes from Canada and California sampled during the summer phase (ARCTAS-B indicated low NOx emission factors from the fires, rapid conversion of NOx to PAN, no significant secondary aerosol production, and no significant ozone enhancements except when mixed with urban pollution.

  12. Using Participatory and Service Design to Identify Emerging Needs and Perceptions of Library Services among Science and Engineering Researchers Based at a Satellite Campus

    Johnson, Andrew; Kuglitsch, Rebecca; Bresnahan, Megan


    This study used participatory and service design methods to identify emerging research needs and existing perceptions of library services among science and engineering faculty, post-graduate, and graduate student researchers based at a satellite campus at the University of Colorado Boulder. These methods, and the results of the study, allowed us…

  13. Using Participatory and Service Design to Identify Emerging Needs and Perceptions of Library Services among Science and Engineering Researchers Based at a Satellite Campus

    Johnson, Andrew; Kuglitsch, Rebecca; Bresnahan, Megan


    This study used participatory and service design methods to identify emerging research needs and existing perceptions of library services among science and engineering faculty, post-graduate, and graduate student researchers based at a satellite campus at the University of Colorado Boulder. These methods, and the results of the study, allowed us…

  14. Coastal ocean research in sub-Saharan Africa: towards operational oceanography using satellites, in situ measurements and numerical models

    Shillington, Frank

    Sub-Saharan Africa is greatly influenced by major western boundary currents of the Indian Ocean, Agulhas Current and the Somali Current (for six months of the year), and the major eastern boundary upwelling current systems of the Atlantic Ocean, with their concomitant nu-trient rich upwelling ecosystems which support large fisheries: the Benguela Upwelling System and the Canary Upwelling System. The location of the tip of placecountry-regionSouth Africa is unique in the world oceans, since it is such the only place where a warm western boundary current can interact with a cold upwelling ecosystem. In addition, the Agulhas Current is unique in that it retroflects 80% of its large volume flux back into the placeIndian Ocean. The interocean transport of warm thermocline water from the Indian to the placeAtlantic ocean is of global importance. Satellite observations of temperature, chlorophyll, sea surface height, and wind and waves have elucidated many of these first order processes. Numerical ocean models forced and constrained by satellite measurements are being increasingly used to place operational oceanography on a sound footing. Partnerships with African and northern hemisphere collaborators (e.g. the new Norwegian Nansen-Tutu Centre for Marine Research, PlaceNamePrinceton PlaceTypeUniversity) will enhance operational oceanography around placeAfrica to the benefit of all its inhabitants. All of the above aspects will be discussed, with specific examples of local innovative space borne techniques.

  15. Satellite Communication.

    Technology Teacher, 1985


    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…

  16. Research on Differential Coding Method for Satellite Remote Sensing Data Compression

    Lin, Z. J.; Yao, N.; Deng, B.; Wang, C. Z.; Wang, J. H.


    Data compression, in the process of Satellite Earth data transmission, is of great concern to improve the efficiency of data transmission. Information amounts inherent to remote sensing images provide a foundation for data compression in terms of information theory. In particular, distinct degrees of uncertainty inherent to distinct land covers result in the different information amounts. This paper first proposes a lossless differential encoding method to improve compression rates. Then a district forecast differential encoding method is proposed to further improve the compression rates. Considering the stereo measurements in modern photogrammetry are basically accomplished by means of automatic stereo image matching, an edge protection operator is finally utilized to appropriately filter out high frequency noises which could help magnify the signals and further improve the compression rates. The three steps were applied to a Landsat TM multispectral image and a set of SPOT-5 panchromatic images of four typical land cover types (i.e., urban areas, farm lands, mountain areas and water bodies). Results revealed that the average code lengths obtained by the differential encoding method, compared with Huffman encoding, were more close to the information amounts inherent to remote sensing images. And the compression rates were improved to some extent. Furthermore, the compression rates of the four land cover images obtained by the district forecast differential encoding method were nearly doubled. As for the images with the edge features preserved, the compression rates are average four times as large as those of the original images.

  17. Basic research and data analysis for the National Geodetic Satellite program and for the Earth Surveys program


    Current research is reported on precise and accurate descriptions of the earth's surface and gravitational field and on time variations of geophysical parameters. A new computer program was written in connection with the adjustment of the BC-4 worldwide geometric satellite triangulation net. The possibility that an increment to accuracy could be transferred from a super-control net to the basic geodetic (first-order triangulation) was investigated. Coordinates of the NA9 solution were computed and were transformed to the NAD datum, based on GEOS 1 observations. Normal equations from observational data of several different systems and constraint equations were added and a single solution was obtained for the combined systems. Transformation parameters with constraints were determined, and the impact of computers on surveying and mapping is discussed.

  18. Earth System Science Research Using Datra and Products from Terra, Aqua, and ACRIM Satellites

    Hutchison, Keith D.


    The report describes the research conducted at CSR to extend MODIS data and products to the applications required by users in the State of Texas. This research presented in this report was completed during the timeframe of August 2004 - December 31, 2007. However, since annual reports were filed in December 2005 and 2006, results obtained during calendar year 2007 are emphasized in the report. The stated goals of the project were to complete the fundamental research needed to create two types of new, Level 3 products for the air quality community in Texas from data collected by NASA s EOS Terra and Aqua missions.

  19. Research and Development initiative of Satellite Technology Application for Environmental Issues in Asia Region

    Hamamoto, K.; Kaneko, Y.; Sobue, S.; Oyoshi, K.


    Climate change and human activities are directly or indirectly influence the acceleration of environmental problems and natural hazards such as forest fires, drought and floods in the Asia-Pacific countries. Satellite technology has become one of the key information sources in assessment, monitoring and mitigation of these hazards and related phenomenon. However, there are still gaps between science and application of space technology in practical usage. Asia-Pacific Regional Space Agency Forum (APRSAF) recommended to initiate the Space Applications for Environment (SAFE) proposal providing opportunity to potential user agencies in the Asia Pacific region to develop prototype applications of space technology for number of key issues including forest resources management, coastal monitoring and management, agriculture and food security, water resource management and development user-friendly tools for application of space technology. The main activity of SAFE is SAFE prototyping. SAFE prototyping is a demonstration for end users and decision makers to apply space technology applications for solving environmental issues in Asia-Pacific region. By utilizing space technology and getting technical support by experts, prototype executers can develop the application system, which could support decision making activities. SAFE holds a workshop once a year. In the workshop, new prototypes are approved and the progress of on-going prototypes are confirmed. Every prototype is limited for two years period and all activities are operated by volunteer manner. As of 2016, 20 prototypes are completed and 6 prototypes are on-going. Some of the completed prototypes, for example drought monitoring in Indonesia were applied to operational use by a local official organization.

  20. LEO卫星星下点轨迹保持策略优化研究%Optimal research on satellite track keeping strategy for low earth orbit satellite

    崔鹏; 傅忠谦


    The most LEO(low earth orbit) satellites run in the sun-synchronous orbit.In order to keep their orbit character and achieve the work condition of satellite equipment,satellite track must be kept by orbit control.This paper analyses the local time of descending node is kept by inclination biased and effect for satellite track of inclination biased and decrease of major semi-axis and chronic change of inclination.It gives the keeping method and compute model of adding major semi-axis biased.The simulation results show that the method achieves the demand of track keeping,and the frequency of orbit control is decreased.There is important meaning in practice application.%在轨运行的LEO(low earth orbit)卫星绝大多数是太阳同步回归轨道,为了保持其轨道特性并满足星上载荷工作条件,必须进行星下点轨迹保持.分析了倾角偏置实现降交点地方时保持的同时对星下点轨迹漂移的影响,以及半长轴衰减和倾角长期变化引起的星下点轨迹漂移,给出了增大半长轴偏置量的星下点轨迹保持方法和计算模型.仿真结果显示,此方法不但满足轨迹保持要求,而且减小了轨道维持频度,在工程应用中有重要的意义.

  1. Approach and status for a unified national plan for satellite remote sensing research and development

    Butera, Kristine; Okerson, David J.


    Public Law 98-365, the Land Remote-Sensing Commercialization Act of 1984, requires that the Secretary of the Department of Commerce and the Administrator of the National Aeronautics and Space Administration 'shall, within one year after the date of the Law's enactment and biennially thereafter, jointly develop and transmit to the Congress a report that includes (1) a unified national plan for remote-sensing research and development applied to the earth and its atmosphere; (2) a compilation of progress in the relevant on-going research and development activities of Federal agencies; and (3) an assessment of the state of our knowledge of the Earth and its atmosphere, the needs for additional research (including research related to operational Federal remote-sensing space programs), and opportunities available for further progress'. NASA and NOAA have organized a series of public forums to encourage interest and discussion of the national plan.

  2. How well can interannual to decadal-scale variability in stratospheric ozone and water vapor be quantified using limb-based satellite measurements?

    Davis, S. M.; Rosenlof, K. H.; Hurst, D. F.; Hassler, B.; Read, W. G.


    Vertical profiles of ozone and humidity from the upper troposphere to stratosphere have been retrieved from a number of limb sounding and solar occultation satellite instruments since the 1980's. In particular, measurements from the SAGE instruments, UARS MLS, UARS HALOE, and most recently Aura MLS, have provided overlapping data since 1984. In order to quantify interannual- to decadal-scale variability in water vapor and ozone, it is necessary to have a uniform and homogenous record over the period of interest. With this in mind, we merged the aforementioned satellite measurements to create the Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) data set, which contains vertically resolved zonal-mean (2.5°) monthly-mean water vapor and ozone concentration at levels covering the stratosphere. In this presentation, we describe the process of merging the satellite data sets, which involves adjusting the data to a reference measurement using offsets calculated from coincident observations taken during instrument overlap periods. Uncertainties associated with individual measurement precision, geophysical variability, and the merging process are quantified and compared to one another. We show that while the SWOOSH data can be used to quantify interannual variability, quantifying long-term trends in SWOOSH is complicated by the various sources of uncertainty, as well as by potential drifts of individual instruments. The issue of satellite-derived trends is discussed in relation to the long-term record of balloon-borne frostpoint hygrometer measurements from Boulder, CO.

  3. Global atmospheric energy deposition by energetic electrons - Quantitative spatial and temporal characteristics inferred from the Atmospheric X-ray Imaging Spectrometer (PEM/AXIS) on UARS

    Chenette, D. L.; Datlowe, D. W.; Robinson, R. M.; Schumaker, T. L.; Vondrak, R. R.; Frahm, R. A.; Sharber, J. R.; Winningham, J. D.


    The primary purpose of PEM/AXIS is to provide a global monitor of the energy input to the upper atmosphere due to energetic electrons. The design, development, and calibration of AXIS are described and an assessment of its excellent on-orbit performance is presented. The unique capabilities of X-ray imaging spectrometers to monitor the global patterns of electron energy deposition in the atmosphere are shown through an analysis of some specific cases during the first year of the UARS mission.

  4. Research on Satellite Network Secure Routing Objectives%卫星网络安全路由目标研究

    周星; 刘军; 董春冻; 张玉静


    确定合适的安全目标是对协议进行安全增强的前提,针对目前对卫星网络路由协议的安全目标研究不充分,没有统一的安全目标的现状,文中对卫星网络路由协议的安全目标进行研究,并提出改进的安全路由目标.通过在现有plausible routing即路由可达的目标基础上对路由消息进行认证性、机密性等保护以增强安全性,并用串空间将所提目标形象地表示.分析表明,改进的安全目标,克服了原plausible routing目标的部分不足,增进了路由协议的安全性.文中提出的安全目标进一步从形式化的方式上对卫星网络路由协议的安全性进行了研究,为以后的研究提供了一定的基础.%It used to be the foremost thing to give a proper secure objectives so as to make a protocol safer,as there has been no sufficient research on secure objectives and no secure objectives is well accepted so far,researched the satellite network secure routing objectives,and gave improved secure routing objectives.Improved the security by doing authentication and confidentiality protection on the basis of plausible routing also named routing reachable,and illustrated it using strand space.Analysis showed the improved objectives solved some drawbacks appeared in the plausible routing,and enhanced the security of routing protocol.The proposed secure objectives further researched satellite network routing protocol formally,offering some fundamentals for later research.

  5. Research in Geodesy Based Upon Radio Interferometric Observations of GPS (Global Positioning System) Satellites.


    1983. Robertson, D. S., Carter, W. E., Eanes, R. J., Schutz , B. E., Tapley, B. D., King, R. W., Langley, R. B., Morgan, P. J., and Shapiro, I. I... Alfred Leick (on leave from the Univ. of Maine) Staff Scientists: Drs. Richard I. Abbot, Yehuda Bock, and Sergei A. Gourevitch Principal Research

  6. Magnet Coil Test Facility for Researching Magnetic Activity of Pico/Nano/Micro Satellites (PNMSats)


    of mapping magnetic fields of nearby planets , moons, asteroids, and such. Impact on Other Disciplines As stated in the previous sections, cross...disciplinary research has been initiated. It is well understood that life form is always under the influence of electro-magnetic force, which is one of...the fundamental forces in nature. An ability to artificially alter the intensity or direction of this force in an environment and subjecting life form

  7. Research on impervious surface dynamic changes based on Landsat satellite images in Nantong, China

    Lu, Xiu; Li, Jia; Duan, Ping; Wang, Jinliang; Zhang, Chi


    In this paper, the decision tree classification based on the CART algorithm (Classification and Regression Tree) is used to extract the impervious surface area of Nantong city in Jiangsu Province in China. Impervious surface dynamic change nearly 25 years in Nantong city is researched using four periods Landsat images of 1990, 2003, 2008, and 2014. The results show that the classification precision based on the CART algorithm is higher, which can more accurately extract the impervious surface. During the 25 years, the trend of the impervious surface of Nantong is increased year by year. Urban construction and expansion is one of the driving forces of the impervious surface increase.

  8. 卫星宽带网络系统的研究与分析%An Analytical Research on Satellite Broadband Network system



    This artical mainly introduces the satellite broadband network system basic principle,technical features, development status and trend of application, through the research and analysis,that the satellite broadband network will be widely used in information communication.%本文主要介绍了卫星宽带网络系统的基本原理、技术特点、发展现状和应用趋势,通过研究和分析,证明了卫星宽带网络在信息通信领域具有广阔的应用前景。

  9. 全球导航星座的远地/深空导航应用研究%The application research of global navigation constellation for HEO (high earth orbit) satellites and deep-space satellites

    赵雯雯; 张立新; 蒙艳松; 宋志强


    It has been widely studied that GNSS(global navigation satellite system) offers navigation for Ground-Based users and LEO(low earth orbit.) users. At present, it mainly depends on Ground-Based measurement and control system that HEO satellites and deep-space satellites determine their orbits and attitude, and synchronize their time. The Ground-Based measurement and control system which has complex equipment and high investment can't support abundant aerocrafts at the same time, and can't operate autonomously. This article studied the possibility of orbit determination, attitude determination, and time synchronization with global navigation constellation for HEO satellites and deep-space satellites, and consequently achieved the extended applications of global navigation constellation. It found out a high efficient way for global navigation constellation to operating as time and space reference for constellation networks, in order that constellation networks autonomously operate and navigate. And it also putted forward a solution to realize passive navigation for HEO satellites and deep-space satellites by skillfully designing the links between satellites, without increasing equipment on satellites. The research focused on the number of visible satellites and GDOP(geometric dilution of precision) value. The precision of positioning and time determination was also analyzed in order to provide new ideas for the construction of global navigation constellation.%全球卫星导航系统为低轨和地面用户提供导航服务已有广泛的研究.中高轨卫星以及深空卫星的定轨、定姿和时间同步,目前主要利用地面测控系统完成,存在设备复杂、投资高、无法同时支持大量飞行器、无法自主运行等缺点.本文研究中高轨卫星和深空卫星利用全球导航星座进行定轨、定姿和授时服务的可行性,实现其扩展应用,寻求全球导航星座作为天基网时空基准的高效途径,使得天基网的

  10. 一种特殊星间链路的应用研究∗%Research on the Application of a Special Inter-satellite Link

    钦伟瑾; 韦沛; 杨旭海


    With the development of scientific research on the LEO (low earth orbit) satellites, their timing and positioning are increasingly prominent. In order to make full use of the existing BD (BeiDou) regional navigation system for the LEO satellites, this paper proposes to build a special inter-satellite-link between high-orbit and LEO satellites. And then we analyze the low-altitude service of this kind of links, including the coverage of timing/positioning, usability for navigation constellation, and the effect on usability when the satellite is invalid. Finally it draws some useful conclusions that the BD satellite system can provide service for the LEO satellites.%随着低轨卫星的科学研究逐渐深入,其定位和授时的需求也日益凸显。针对如何利用现有北斗区域系统为低轨卫星服务,提出在高轨卫星与低轨卫星间建立一种特殊链路。从授时定位覆盖比,导航星座可用性,以及卫星失效对导航星座可用性的影响3方面分析北斗区域系统服务性能,得出有益结论,为北斗天基系统服务低轨卫星提供支撑。

  11. Cooperative and cognitive satellite systems

    Chatzinotas, Symeon; De Gaudenzi, Riccardo


    Cooperative and Cognitive Satellite Systems provides a solid overview of the current research in the field of cooperative and cognitive satellite systems, helping users understand how to incorporate state-of-the-art communication techniques in innovative satellite network architectures to enable the next generation of satellite systems. The book is edited and written by top researchers and practitioners in the field, providing a comprehensive explanation of current research that allows users to discover future technologies and their applications, integrate satellite and terrestrial systems

  12. Measuring the Value of Earth Observation Information with the Gravity Research and Climate Experiment (GRACE) Satellite

    Bernknopf, R.; Kuwayama, Y.; Brookshire, D.; Macauley, M.; Zaitchik, B.; Pesko, S.; Vail, P.


    Determining how much to invest in earth observation technology depends in part on the value of information (VOI) that can be derived from the observations. We design a framework and then evaluate the value-in-use of the NASA Gravity Research and Climate Experiment (GRACE) for regional water use and reliability in the presence of drought. As a technology that allows measurement of water storage, the GRACE Data Assimilation System (DAS) provides information that is qualitatively different from that generated by other water data sources. It provides a global, reproducible grid of changes in surface and subsurface water resources on a frequent and regular basis. Major damages from recent events such as the 2012 Midwest drought and the ongoing drought in California motivate the need to understand the VOI from remotely sensed data such as that derived from GRACE DAS. Our conceptual framework models a dynamic risk management problem in agriculture. We base the framework on information from stakeholders and subject experts. The economic case for GRACE DAS involves providing better water availability information. In the model, individuals have a "willingness to pay" (wtp) for GRACE DAS - essentially, wtp is an expression of savings in reduced agricultural input costs and for costs that are influenced by regional policy decisions. Our hypothesis is that improvements in decision making can be achieved with GRACE DAS measurements of water storage relative to data collected from groundwater monitoring wells and soil moisture monitors that would be relied on in the absence of GRACE DAS. The VOI is estimated as a comparison of outcomes. The California wine grape industry has features that allow it to be a good case study and a basis for extrapolation to other economic sectors. We model water use in this sector as a sequential decision highlighting the attributes of GRACE DAS input as information for within-season production decisions as well as for longer-term water reliability.

  13. Spatial Downscaling Research of Satellite Land Surface Temperature Based on Spectral Normalization Index

    LI Xiaojun


    Full Text Available Aiming at the problem that the spatial and temporal resolution of land surface temperature (LST have the contradiction with each other, a new downscaling model was put forward, based on the TsHARP(an algorithm for sharpening thermal imagery downscaling method, this research makes improvements by selecting the better correlation of spectral index(normalized difference vegetation index, NDVI; normalized difference build-up index, NDBI; modified normalized difference water index, MNDWI; enhanced bare soil index, EBSI with LST, i.e., replaces the original NDVI with new spectral index according to the different surface land-cover types, to assess the accuracy of each downscaling method based on qualitative and quantitative analysis with synchronous Landsat 8 TIRS LST data. The results show that both models could effectively enhance the spatial resolution while simultaneously preserving the characteristics and spatial distribution of the original 1 km MODIS LST image, and also eliminate the “mosaic” effect in the original 1 km image, both models were proved to be effective and applicable in our study area; global scale analysis shows that the new model (RMSE:1.635℃ is better than the TsHARP method (RMSE:2.736℃ in terms of the spatial variability and accuracy of the results; the different land-cover types of downscaling statistical analysis shows that the TsHARP method has poor downscaling results in the low vegetation coverage area, especially for the bare land and building-up area(|MBE|>3℃, the new model has obvious advantages in the description of the low vegetation coverage area. Seasonal analysis shows that the downscaling results of two models in summer and autumn are superior to those in spring and winter, the new model downscaling results are better than the TsHARP method in the four seasons, in which the spring and winter downscaling improvement is better than summer and autumn.

  14. Use of Fourier transforms for asynoptic mapping: Applications to the Upper Atmosphere Research Satellite microwave limb sounder

    Elson, Lee S.; Froidevaux, Lucien


    Fourier analysis has been applied to data obtained from limb viewing instruments on the Upper Atmosphere Research Satellite. A coordinate system rotation facilitates the efficient computation of Fourier transforms in the temporal and longitudinal domains. Fields such as ozone (O3), chlorine monoxide (ClO), temperature, and water vapor have been transformed by this process. The transforms have been inverted to provide maps of these quantities at selected times, providing a method of accurate time interpolation. Maps obtained by this process show evidence of both horizontal and vertical transport of important trace species such as O3 and ClO. An examination of the polar regions indicates that large-scale planetary variations are likely to play a significant role in transporting midstratospheric O3 into the polar regions. There is also evidence that downward transport occurs, providing a means of moving O3 into the polar vortex at lower altitudes. The transforms themselves show the structure and propagation characteristics of wave variations.

  15. The Use of a Satellite Communications System for Command and Control of the National Aeronautics and Space Administration Surrogate Unmanned Aerial System Research Aircraft

    Howell, Charles T.; Jones, Frank; Hutchinson, Brian; Joyce, Claude; Nelson, Skip; Melum, Mike


    The NASA Langley Research Center has transformed a Cirrus Design SR22 general aviation (GA) aircraft into an Unmanned Aerial Systems (UAS) Surrogate research aircraft which has served for several years as a platform for unmanned systems research and development. The aircraft is manned with a Safety Pilot and a Research Systems Operator (RSO) that allows for flight operations almost any-where in the national airspace system (NAS) without the need for a Federal Aviation Administration (FAA) Certificate of Authorization (COA). The UAS Surrogate can be remotely controlled from a modular, transportable ground control station (GCS) like a true UAS. Ground control of the aircraft is accomplished by the use of data links that allow the two-way passage of the required data to control the aircraft and provide the GCS with situational awareness. The original UAS Surrogate data-link system was composed of redundant very high frequency (VHF) data radio modems with a maximum range of approximately 40 nautical miles. A new requirement was developed to extend this range beyond visual range (BVR). This new requirement led to the development of a satellite communications system that provided the means to command and control the UAS Surrogate at ranges beyond the limits of the VHF data links. The system makes use of the Globalstar low earth orbit (LEO) satellite communications system. This paper will provide details of the development, implementation, and flight testing of the satellite data communications system on the UAS Surrogate research aircraft.

  16. Estimation of the demand for public services communications. [market research and economic analysis for a communications satellite system


    Market analyses and economic studies are presented to support NASA planning for a communications satellite system to provide public services in health, education, mobile communications, data transfer, and teleconferencing.

  17. Routing Technology Research for LEO Satellite Constellation Networks%低轨道卫星星座网络路由研究

    蒋文娟; 宗鹏


    Because of the particular features of LEO satellite networks, such as dynamic topology, non-homogeneous traffic distribution,limited power and processing, new satellite routing approaches should be developed. How to design simple and efficient routing algorithm becomes the hot topic of LEO satellite networks. Analyze the characteristics of LEO satellite networks, and then survey the cunrrent LEO satellite routing algorithms classified with the geometric model, handoff and onboard processing capability. Typical algorithms of each class are presented and their advantages, suitable environment and shortcomings with a detailed comprehensive comparison are discussed. The end of the paper points out the future research field for LFO satellite routing prob1em.%拓扑时变性、承载业务分布不均衡以及星上资源有限,使得设计新的低轨道卫星星座网络路由算法迫在眉睫.如何设计简单、高效的低轨道卫星星座路由成为当前卫星网络研究的热点问题.深入剖析了LEO卫星网络的特点,从几何模型、切换以及星上处理能力三个视角出发,分类综述了LEO卫星路由算法,阐述了各类路由的典型算法,讨论了每种算法的优点和适用环境,剖析了其中存在的问题,并对它们进行了综合对比.最后指出了LEO卫星路由算法进一步的研究方向.

  18. Satellite orbit determination and gravity field recovery from satellite-to-satellite tracking

    Wakker, K. F.; Ambrosius, B. A. C.; Leenman, H.


    Studies on satellite-to-satellite tracking (SST) with POPSAT (a geodetic satellite concept) and a ERS-class (Earth observation) satellite, a Satellite-to-Satellite Tracking (SST) gravity mission, and precise gravity field determination methods and mission requirements are reported. The first two studies primarily address the application of SST between the high altitude POPSAT and an ERS-class or GRM (Geopotential Research Mission) satellite to the orbit determination of the latter two satellites. Activities focussed on the determination of the tracking coverage of the lower altitude satellite by ground based tracking systems and by POPSAT, orbit determination error analysis and the determination of the surface forces acting on GRM. The third study surveys principles of SST, uncertainties of existing drag models, effects of direct luni-solar attraction and tides on orbit and the gravity gradient observable. Detailed ARISTOTELES (which replaced POPSAT) orbit determination error analyses were performed for various ground based tracking networks.

  19. DFH Satellite Co.,Ltd.



    DFH Satellite Co.,Ltd. is a hi-tech enterprise founded and sponsored by China Aerospace Science and Technology Corporation(CASC) and one of CASC subsidiaries,China Academy of Space Technology (CAST). The company is mainly engaged in the research and development of small satellites and micro-satellites, Osystem designs and product development for satellite application projects as well as the international exchanges and cooperation.

  20. Using high-resolution satellite imagery to engage students in classroom experiences which meld research, the nature of science, and inquiry-based instruction

    Pennycook, J.; LaRue, M.; Herried, B.; Morin, P. J.


    Recognizing the need to bridge the gap between scientific research and the classroom, we have developed an exciting activity which engages students in grades 5-12 using high-resolution satellite imagery to observe Weddell seal populations in Antarctica. Going beyond the scope of the textbook, students experience the challenge researchers face in counting and monitoring animal populations in the field. The activity is presented in a non-expert, non-technical exercise enriched for students, with background information, tutorials, and satellite imagery included. Teachers instruct their class in how to use satellite imagery analysis techniques to collect data on seal populations in the McMurdo Sound region of the Ross Sea, Antarctica. Students participate in this inquiry-based, open-ended exercise to evaluate changes in the seal population within and between seasons. The activity meets the New Generation Science Standards (NGSS) through inquiry-based, real-world application and supports seven Performance Expectations (PE) for grade 5-12. In addition, it offers students a glimpse into the work of a field biologist, promoting interest in entering the STEM career pipeline. As every new Antarctica season unfolds, new imagery will be uploaded to the website allowing each year of students to add their counts to a growing long-term dataset for the classroom. The activity files provide 1) a tutorial in how to use the images to count the populations, 2) background information about Weddell seals in the McMurdo Sound region of the Ross Sea for the students and the teachers, and 3) collections of satellite imagery for spatial and temporal analysis of population fluctuations. Teachers can find all activity files to conduct the activity, including student instructions, on the Polar Geospatial Center's website ( Satellite image, Big Razorback Island, Antarctica Weddell seals,Tent Island, Antarctica

  1. Modeling Research on Joint Scheduling of Multiple Imaging Satellites with Multiple Sensors%多星多载荷联合调度问题建模研究

    潘鞘剑; 周装轻; 贺仁杰; 邢立宁


    在对多星多载荷联合调度过程及约束条件分析的基础上,从约束建模及启发式调度规则设计的角度对多星多载联合调度方案生成中的关键问题进行了深入研究.建立了基于阶段优化的多星多载荷联合调度模型.提出了基于规则的发式构造算法.%Guided by the application requirements of imaging satellite, the model construction and heuristic rule design of multi imaging satellites joint scheduling problem are focused. All of the research are based on the a-nalysis of the process of joint scheduling and imaging constraints. Firstly, this thesis analyses satellite imaging procedure , imaging constraints, input and output of the problem, ascertains the basic scheduling flow and characteristics of the multi imaging satellites joint scheduling problem. Secondly, in order to solve the problem the construction of heuristic algorithms is focused on.

  2. Research of the Satellite Interference Location System%卫星干扰源定位系统的研究

    陈霄; 徐慨; 董蛟; 杨朝


    卫星通信系统是一个开放式的系统,在平时和战时都可能受到干扰,为了能够准确地掌控所使用卫星通信链路的状态,需要具备对我国使用的卫星转发器进行频谱监视、干扰源分析定位的能力,因此研究卫星干扰源定位系统的原理和算法具有重要的意义。%Satellite communication system is an open system, so it is likely to be disturbed in peacetime and wartime, in order to be able to accurately control the use of satellite communication link state, we need the ability to monitor the spectrum of sat-ellite transponder and locate the satellite interference. So the principle and algorithm of satellite interference source and positio-ning system has important significance.

  3. The World Largest Small Satellite R&D Center Completed


    The National Institute of Small Satellite Research and Applications, constructed by Dongfanghong Satellite Company,was completed on December 14,2004. It is the world largest satellite research and development center.

  4. Satellite RNAs and Satellite Viruses.

    Palukaitis, Peter


    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.

  5. Applications of NASA and NOAA Satellite Observations by NASA's Short-term Prediction Research and Transition (SPoRT) Center in Response to Natural Disasters

    Molthan, Andrew L.; Burks, Jason E.; McGrath, Kevin M.; Jedlovec, Gary J.


    NASA s Short-term Prediction Research and Transition (SPoRT) Center supports the transition of unique NASA and NOAA research activities to the operational weather forecasting community. SPoRT emphasizes real-time analysis and prediction out to 48 hours. SPoRT partners with NOAA s National Weather Service (NWS) Weather Forecast Offices (WFOs) and National Centers to improve current products, demonstrate future satellite capabilities and explore new data assimilation techniques. Recently, the SPoRT Center has been involved in several activities related to disaster response, in collaboration with NOAA s National Weather Service, NASA s Applied Sciences Disasters Program, and other partners.

  6. Research on long-term autonomous orbit determination for navigation constellation using inter-satellite orientation observation information

    Li, Bo; Xu, Bo; Wang, Hai-Hong


    Long-term autonomous orbit determination is one of the key techniques of autonomous navigation for navigation constellation. Based only on cross-link range observation, which is not able to overcome the defect of entire constellation rotation and translation relative to inertial reference frame, the accuracy of autonomous orbit determination is reduced with time. In order to solve this problem, the approach of using inter-satellite orientation observation is put forward to estimate the constellation rotation and translation with the benefit of absolute position information provided by stars. In view of the fact that most navigation satellites moving in near circular orbits, and also in order to reduce the calculation burden of onboard computer, nonsingular orbital elements are chosen as state variables and analytical method is used to calculate the transition matrix in this paper. In addition, the extended Kalman filter is designed to fuse information of satellite dynamic model, cross-link range observation and inter-satellite orientation observation to determine the orbit. The simulation results based on the IGS Final Products of GPS constellation indicate that, at the certain error condition of range and orientation measurement, the URE of constellation is better than 2 meters within 120 days.

  7. Centriolar satellites

    Tollenaere, Maxim A X; Mailand, Niels; Bekker-Jensen, Simon


    Centriolar satellites are small, microscopically visible granules that cluster around centrosomes. These structures, which contain numerous proteins directly involved in centrosome maintenance, ciliogenesis, and neurogenesis, have traditionally been viewed as vehicles for protein trafficking...... highlight newly discovered regulatory mechanisms targeting centriolar satellites and their functional status, and we discuss how defects in centriolar satellite components are intimately linked to a wide spectrum of human diseases....

  8. Satellite theory

    Kozai, Y.


    The dynamical characteristics of the natural satellite of Mars, Jupiter, Saturn, Uranus and Neptune are analyzed on the basis of the solar tidal perturbation factor and the oblateness factor of the primary planet for each satellite. For the inner satellites, for which the value of the solar tidal factor is much smaller than the planetary oblateness factor, it is shown that the eccentricity and inclination of satellite orbits are generally very small and almost constant; several pairs of inner satellites are also found to exhibit commensurable mean motions, or secular accelerations in mean longitude. In the case of the outer satellites, for which solar perturbations are dominant, secular perturbations and long-period perturbations may be derived by the solution of equations of motion reduced to one degree of freedom. The existence of a few satellites, termed intermediary satellites, for which the solar tidal perturbation is on the order of the planetary oblateness factor, is also observed, and the pole of the orbital plane of the satellite is noted to execute a complex motion around the pole of the planet or the orbital plane of the planet.

  9. Research on the acquisition and tracking simulation system of light beacon in satellite-ground optical communications

    ZUO Tao; AI Yong; HUANG Hai-bo; SU Gui-bo


    @@ The study on the acquisition and tracking simulation system in satellite-ground optical communications is presented here.By applying global positioning system(GPS)coordinate calculation,the time needed in initial acquisition of light beacon can be reduced largely.Smith predictor is applied to compensate the mechanical hysteresis of tracking system and to improve the dynamic performance of the system.Tracking experiments over a i 6 km distance on the ground are conducted to verify the tracking of light beacon in satellite-ground optical communications.The standard deviation of horizontal coordinates is 35.3568 μrad and the maximum offset is 209.3675 μrad in stable tracking.

  10. Research on the classification result and accuracy of building windows in high resolution satellite images: take the typical rural buildings in Guangxi, China, as an example

    Li, Baishou; Gao, Yujiu


    The information extracted from the high spatial resolution remote sensing images has become one of the important data sources of the GIS large scale spatial database updating. The realization of the building information monitoring using the high resolution remote sensing, building small scale information extracting and its quality analyzing has become an important precondition for the applying of the high-resolution satellite image information, because of the large amount of regional high spatial resolution satellite image data. In this paper, a clustering segmentation classification evaluation method for the high resolution satellite images of the typical rural buildings is proposed based on the traditional KMeans clustering algorithm. The factors of separability and building density were used for describing image classification characteristics of clustering window. The sensitivity of the factors influenced the clustering result was studied from the perspective of the separability between high image itself target and background spectrum. This study showed that the number of the sample contents is the important influencing factor to the clustering accuracy and performance, the pixel ratio of the objects in images and the separation factor can be used to determine the specific impact of cluster-window subsets on the clustering accuracy, and the count of window target pixels (Nw) does not alone affect clustering accuracy. The result can provide effective research reference for the quality assessment of the segmentation and classification of high spatial resolution remote sensing images.

  11. Research on the Status Quo of Satellite Optical Communication%卫星光通信的现状研究



    在空间卫星通信中,激光通信技术是一种能够传输大容量数据的计术。文章整理了一些卫星光通信的实验数据。特别是日本宇宙航空研究开发机构(JAXA)的光学轨道间通信工程试验卫星(OICETS)与日本国家信息通信技术研究所(NICT)光学地面站之间的低轨道双向光学通信试验。试验成功的证明了在大气环境影响下激光通信的可行性。%In satellite communications, laser communication technology is a transmission of large capacity data technology. Experimental data of some satellite optical communication are organized in this paper. In particular, the Japan Aerospace Exploration Agency (JAXA) optical inter orbit communications engineering test satellite (oicets) and Japanese national information and communication technology of the (NICT) optical ground station between low earth orbit bi-directional optical communication test. The feasibility of laser communication in atmosphere is proved successfully.

  12. Life Science Research in Outer Space: New Platform Technologies for Low-Cost, Autonomous Small Satellite Missions

    Ricco, Antonio J.; Parra, Macarena P.; Niesel, David; McGinnis, Michael; Ehrenfreund, Pascale; Nicholson, Wayne; Mancinelli, Rocco; Piccini, Matthew E.; Beasley, Christopher C.; Timucin, Linda R.; Ricks, Robert D.; McIntyre, Michael J.; Squires, David; Yost, Bruce D.; Hines, John W.


    We develop integrated instruments and platforms suitable for economical, frequent space access for autonomous life science experiments and processes in outer space. The technologies represented by three of our recent free-flyer small-satellite missions are the basis of a rapidly growing toolbox of miniaturized biologically/biochemically-oriented instrumentation now enabling a new generation of in-situ space experiments. Autonomous small satellites ( 1 50 kg) are less expensive to develop and build than fullsize spacecraft and not subject to the comparatively high costs and scheduling challenges of human-tended experimentation on the International Space Station, Space Shuttle, and comparable platforms. A growing number of commercial, government, military, and civilian space launches now carry small secondary science payloads at far lower cost than dedicated missions; the number of opportunities is particularly large for so-called cube-sat and multicube satellites in the 1 10 kg range. The recent explosion in nano-, micro-, and miniature technologies, spanning fields from telecommunications to materials to bio/chemical analysis, enables development of remarkably capable autonomous miniaturized instruments to accomplish remote biological experimentation. High-throughput drug discovery, point-of-care medical diagnostics, and genetic analysis are applications driving rapid progress in autonomous bioanalytical technology. Three of our recent missions exemplify the development of miniaturized analytical payload instrumentation: GeneSat-1 (launched: December 2006), PharmaSat (launched: May 2009), and O/OREOS (organism/organics exposure to orbital stresses; scheduled launch: May 2010). We will highlight the overall architecture and integration of fluidic, optical, sensor, thermal, and electronic technologies and subsystems to support and monitor the growth of microorganisms in culture in these small autonomous space satellites, including real-time tracking of their culture

  13. Satellite Communications

    Pelton, Joseph N


    The field of satellite communications represents the world's largest space industry. Those who are interested in space need to understand the fundamentals of satellite communications, its technology, operation, business, economic, and regulatory aspects. This book explains all this along with key insights into the field's future growth trends and current strategic challenges. Fundamentals of Satellite Communications is a concise book that gives all of the key facts and figures as well as a strategic view of where this dynamic industry is going. Author Joseph N. Pelton, PhD, former Dean of the International Space University and former Director of Strategic Policy at Intelstat, presents a r

  14. Interim Service ISDN Satellite (ISIS) network model for advanced satellite designs and experiments

    Pepin, Gerard R.; Hager, E. Paul


    The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Network Model for Advanced Satellite Designs and Experiments describes a model suitable for discrete event simulations. A top-down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ISDN modeling abstractions are added to permit the determination and performance for the NASA Satellite Communications Research (SCAR) Program.

  15. Satellite Geomagnetism

    Olsen, Nils; Stolle, Claudia


    Observations of Earth’s magnetic field from space began more than 50 years ago. A continuous monitoring of the field using low Earth orbit (LEO) satellites, however, started only in 1999, and three satellites have taken highprecision measurements of the geomagnetic field during the past decade...... ability to characterize and understand the many sources that contribute to Earth’s magnetic field. In this review, we summarize investigations of Earth’s interior and environment that have been possible through the analysis of high-precision magnetic field observations taken by LEO satellites........ The unprecedented time-space coverage of their data opened revolutionary new possibilities for monitoring, understanding, and exploring Earth’s magnetic field. In the near future, the three-satellite constellation Swarm will ensure continuity of such measurement and provide enhanced possibilities to improve our...

  16. Satellite (Natural)

    Murdin, P.


    In its most general sense, any celestial object in orbit around a similar larger object. Thus, for example, the Magellanic Clouds are satellite galaxies of our own Milky Way galaxy. Without qualification, the term is used to mean a body in orbit around a planet; an alternative term is moon. The term natural satellite distinguishes these bodies from artificial satellites—spacecraft placed in orbi...

  17. Chemiluminescent methods and instruments for monitoring of the atmosphere and satellite validation on board of research aircrafts and unmanned aerial vehicles

    Sitnikov, Nikolay; Borisov, Yuriy; Akmulin, Dimitry; Chekulaev, Igor; Sitnikova, Vera; Ulanovsky, Alexey; Sokolov, Alexey

    The results of development of instruments based on heterophase chemiluminescence for measurements of space distribution of ozone and nitrogen oxides concentrations on board of research aircrafts and unmanned aerial vehicles carried out in Central Aerological Observatory are presented. Some results of atmospheric investigations on board of research aircrafts M55 “Geophysica” (Russia) and “Falcon” (Germany) carried out using developed instruments in frame of international projects are demonstrated. Small and low power instruments based on chemiluminescent principle for UAV are developed. The results of measurements on board of UAV are shown. The development can be used for satellite data validation, as well as operative environmental monitoring of contaminated areas in particular, chemical plants, natural and industrial disasters territories, areas and facilities for space purposes etc.

  18. Scientific Satellites


    followed Hale’s into orbit. In 1879, Jules Verne wrote about launching small satellites with a gun possessing a muzzle velocity of 10 000 m/sec (ref. 3...was activated in 1950.11 It was located only a few tens of miles from the spot where Jules Verne had his Baltimore Gun Club fire a manned projectile to...principle, satellites can be launched by a single impulse applied at the Earth’s surface-say, with a large cannon, & la Jules Verne (sec. 8-3). In

  19. Satellite Communications for ATM

    Shamma, Mohammed A.


    This presentation is an overview on Satellite Communication for the Aeronautical Telecommunication Management (ATM) research. Satellite Communications are being considered by the FAA and NASA as a possible alternative to the present and future ground systems supporting Air Traffic Communications. The international Civil Aviation Organization (ICAO) have in place Standards and Recommended Practices (SARPS) for the Aeronautical Mobile Satellite Services (AMSS) which is mainly derived from the pre-existing Inmarsat service that has been in service since the 1980s. The Working Group A of the Aeronautical Mobile Communication Panel of ICAO has also been investigating SARPS for what is called the Next Generation Satellite Service (NGSS) which conforms less to the Inmarsat based architecture and explores wider options in terms of satellite architectures. Several designs are being proposed by Firms such as Boeing, ESA, NASA that are geared toward full or secondary usage of satellite communications for ATM. Satellite communications for ATM can serve several purposes ranging from primary usage where ground services would play a minimal backup role, to an integrated solution where it will be used to cover services, or areas that are less likely to be supported by the proposed and existing ground infrastructure. Such Integrated roles can include usage of satellite communications for oceanic and remote land areas for example. It also can include relieving the capacity of the ground network by providing broadcast based services of Traffic Information Services messages (TIS-B), or Flight Information Services (FIS-B) which can take a significant portion of the ground system capacity. Additionally, satellite communication can play a backup role to support any needs for ground replacement, or additional needed capacity even after the new digital systems are in place. The additional bandwidth that can be provided via satellite communications can also open the door for many new

  20. Research on the Orbit Keeping of Satellite%卫星运行轨道保持研究

    冯艳; 张忠峰


    With the known control law, the initial value range of state variables are determined by genetic algorithm.Then fixed point can be accurately obtained by Newton-Raphson's iteration.Finally attraction region of fixed point of orbit keeping is obtained by cell-to-cell mapping method.The results indicate that the orbit of satellite can keep if the state variables and control law satisfy given conditions.%在控制量已知的条件下,首先用遗传算法确定了卫星轨道保持所需初始状态量的范围,再用Newton-Raphson迭代法精确求得不动点,最后用胞映射法计算得到轨道保持不动点的吸引域.结果表明:只要控制量和状态量满足特定条件,卫星的运行轨道就能保持.

  1. TC-1 Satellite of DSP Delivered



    TC-1 satellite of Double Star Program (DSP), a near-earth equatorial satellite, was delivered to the representative of the end user, the Research Center for Space Science and Application under the Chinese Academy of Sciences (CAS) on April 12, 2004, which symbolized that TC-1 satellite was put into operation formally.

  2. Mean vertical wind in the mesosphere-lower thermosphere region (80–120 km deduced from the WINDII observations on board UARS

    V. Fauliot

    Full Text Available The WINDII interferometer placed on board the Upper Atmosphere Research Satellite measures temperature and wind from the O(1S green-line emission in the Earth's mesosphere and lower thermosphere. It is a remote-sensing instrument providing the horizontal wind components. In this study, the vertical winds are derived using the continuity equation. Mean wind annually averaged at equinoxes and solstices is shown. Ascendance and subsidence to the order of 1–2 cm s–1 present a seasonal occurrence at the equator and tropics. Zonal Coriolis acceleration and adiabatic heating and cooling rate associated to the mean meridional and vertical circulations are evaluated. The line emission rate measured together with the horizontal wind shows structures in altitude and latitude correlated with the meridional and vertical wind patterns. The effect of wind advection is discussed.

  3. Evaluation of the aerosol indirect effect using satellite, tracer transport model, and aircraft data from the International Consortium for Atmospheric Research on Transport and Transformation

    Avey, L.; Garrett, T. J.; Stohl, A.


    The magnitudes of the "indirect effects" that anthropogenic aerosols have on clouds and climate remain uncertain. Past space-based characterizations have compared satellite retrievals of cloud properties with satellite- or model-derived aerosol quantities. The two fields have been taken from air masses displaced from each other either horizontally or vertically. Thus, almost by definition, the cloud retrievals have come from different meteorological regimes than the aerosol to which ostensibly they are related. Because cloud properties depend foremost on meteorology, the difference introduces undesired ambiguity in the comparisons. In this study, we compare Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) cloud retrievals with high spatial and temporal resolution output from a tracer transport model (FLEXPART), enabling colocation of fields of pollution and clouds both vertically and horizontally. Anthropogenic carbon monoxide (CO) is used as a passive pollution tracer, because its concentrations are tied to mixing and pollutant source strength, and they are independent of atmospheric oxidation and removal processes on timescales of weeks to months. Cloud and pollution fields are compared along a downwind axis from the U.S. northeastern seaboard for the duration of the summer 2004 International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) mission. Where the transport model indicates air as being polluted, cloud re is smaller and cloud optical depth is in some cases higher, at least close to primary source regions. However, within 4 ± 1 days advection time from the northeastern seaboard, cloud perturbations become negligible, probably because of wet-scavenging of CCN. No conclusive evidence was found for any perturbation to cloud liquid water path by pollution.

  4. Research on a New Program of Satellite Network Security Certification%一种新型卫星网络安全认证方案的研究

    高婧; 朱晨光


    在卫星网络通信中,卫星的安全防护是卫星通信系统建设的重要内容之一.结合卫星网络的特点,在对卫星网络的安全认证需求进行分析的基础上,提出了一种基于ELGamal数字签名的卫星网络安全双向认证方案,以解决卫星干扰、非法盗用卫星资源的问题;克服了传统认证方案中普遍存在的认证效率较低和认证过程较复杂等问题,如将该方案加以推广,可以广泛采用.%In the communication of satellite network, the security of satellite is an important content in the development of satellite communication system.Combining with the characteristics of satellite network and analyzing the safety certification requirements of satellite network, a two-way satellite network security certification program based on EIGamal digital signature is introduced to address the satellite interference, illegal use of satellite resources, and overcome the low efficiency and complex process certification existed in traditional common certification.This program can he widely adopted.

  5. Surface-Satellite Measurements for Atmospheric Radiative Transfer (SMART)and Chemical, Optical and Microphysical Measurements of In-Situ Troposphere (COMMIT) Research Activities

    Tsay, Si-Chee


    The GSFC SMART consists of a suite of remote sensing instruments, including many commercially available radiometers, spectrometer, interferometer, and three in-house developed inskuments: micro-pulse lidar (MPL), scanning microwave radiometer (SMiR), and sun-sky-surface photometer (S(sup 3)). SMART cover the spectral range from UV to microwave, and passive to active remote sensing. This is to enrich the EOS-like research activities (i.e., EOS validation, innovative investigations, and long-term local environmental observations). During past years, SMART has been deployed in many NASA supported field campaigns to collocate with satellite nadir overpass for intercomparisons, and for initializing model simulations. Built on the successful experience of SMART, we are currently developing a new ground-based in-situ sampling package, COMMIT, including measurements of trace gases (CO, SO2, NOx, and O3,) concentrations, fine/coarse particle sizers and chemical composition, single- and three-wavelength nephelometers, and surface meteorological probes. COMMIT is built for seeking a relationship between surface in-situ measurements and boundary layer characteristics. This is to enrich EOS-like research on removing boundary layer signal from the entire column from space observation - to deduce the stable (less variability) free-troposphere observations. The COMMIT will try its best to link the chemical, microphysical, and optical properties of the boundary layer with radiation. The next major activities for SMART-COMMIT are scheduled for 2004-2006 in BASE-ASIA and EAST-AIRE. The expected close collaboration of BASE-ASIA with various research projects in Asia (i.e., ABC in South Asia, led by Ramanathan et al.; EAST-AIRE in East Asia, led by Li et al.; and APEX in Northeast Asia, led by Nakajima et al.) will definitely provide a better understanding of the impact of the biomass burning and air pollutants on regional-to-global climate, hydrological and carbon cycles, and

  6. An introduction to optimal satellite range scheduling

    Vázquez Álvarez, Antonio José


    The satellite range scheduling (SRS) problem, an important operations research problem in the aerospace industry consisting of allocating tasks among satellites and Earth-bound objects, is examined in this book. SRS principles and solutions are applicable to many areas, including: Satellite communications, where tasks are communication intervals between sets of satellites and ground stations Earth observation, where tasks are observations of spots on the Earth by satellites Sensor scheduling, where tasks are observations of satellites by sensors on the Earth. This self-contained monograph begins with a structured compendium of the problem and moves on to explain the optimal approach to the solution, which includes aspects from graph theory, set theory, game theory and belief networks. This book is accessible to students, professionals and researchers in a variety of fields, including: operations research, optimization, scheduling theory, dynamic programming and game theory. Taking account of the distributed, ...

  7. Astrophysics with small satellites in Scandinavia

    Lund, Niels


    The small-satellites activities in the Scandinavian countries are briefly surveyed with emphasis on astrophysics research. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.......The small-satellites activities in the Scandinavian countries are briefly surveyed with emphasis on astrophysics research. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved....

  8. Tactical Satellite 3

    Davis, T. M.; Straight, S. D.; Lockwook, R. B.


    Tactical Satellite 3 is an Air Force Research Laboratory Science and Technology (S&T) initiative that explores the capability and technological maturity of small, low-cost satellites. It features a low cost "plug and play" modular bus and low cost militarily significant payloads - a Raytheon developed Hyperspectral imager and secondary payload data exfiltration provided by the Office of Naval Research. In addition to providing for ongoing innovation and demonstration in this important technology area, these S&T efforts also help mitigate technology risk and establish a potential concept of operations for future acquisitions. The key objectives are rapid launch and on-orbit checkout, theater commanding, and near-real time theater data integration. It will also feature a rapid development of the space vehicle and integrated payload and spacecraft bus by using components and processes developed by the satellite modular bus initiative. Planned for a late summer 2008 launch, the TacSat-3 spacecraft will collect and process images and then downlink processed data using a Common Data Link. An in-theater tactical ground station will have the capability to uplink tasking to spacecraft and will receive full data image. An international program, the United Kingdom Defence Science and Technology Laboratory (DSTL) and Australian Defence Science and Technology Organisation (DSTO) plan to participate in TacSat-3 experiments.

  9. Geostationary Satellite (GOES) Images

    National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from radiometer instruments on SMS (ATS) and GOES satellites in geostationary orbit. These satellites produced...

  10. Neptune's small satellites

    Thomas, P.


    The small satellites of Neptune and other planets discovered during the Voyager 2 mission are discussed in terms of their composition and relationship to the planetary systems. The satellite Proteus is described in terms of its orbit, five other satellites are described, and they are compared to ther small satellites and systems. Neptune's satellites are hypothesized to be related to the ring system, and the satellite Galatea is related to the confinement of the rings.

  11. Biogeography based Satellite Image Classification

    Panchal, V K; Kaur, Navdeep; Kundra, Harish


    Biogeography is the study of the geographical distribution of biological organisms. The mindset of the engineer is that we can learn from nature. Biogeography Based Optimization is a burgeoning nature inspired technique to find the optimal solution of the problem. Satellite image classification is an important task because it is the only way we can know about the land cover map of inaccessible areas. Though satellite images have been classified in past by using various techniques, the researchers are always finding alternative strategies for satellite image classification so that they may be prepared to select the most appropriate technique for the feature extraction task in hand. This paper is focused on classification of the satellite image of a particular land cover using the theory of Biogeography based Optimization. The original BBO algorithm does not have the inbuilt property of clustering which is required during image classification. Hence modifications have been proposed to the original algorithm and...

  12. Interim Service ISDN Satellite (ISIS) simulator development for advanced satellite designs and experiments

    Pepin, Gerard R.


    The simulation development associated with the network models of both the Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures is documented. The ISIS Network Model design represents satellite systems like the Advanced Communications Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) Program, moves all control and switching functions on-board the next generation ISDN communications satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete event simulation experiments will be performed with these models using various traffic scenarios, design parameters, and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

  13. 分布式卫星系统数传调度研究%Research on Transmission Task Scheduling for Distributed Satellite Systems

    国晓博; 刘金灿; 周红彬


    With the increase of in⁃orbit sensing satellite,the current relay satellite system is facing a major challenge in terms of data transmission performance.While the payload capability is restricted by satellite platform,the distributed satellite system is a practi⁃cal solution to tremendously improve the performance of relay satellite system. The transmission task scheduling problem of distributed satellite system is studied, a multi⁃satellites multi⁃tasks transmission task scheduling model is proposed based on PSO algorithm by jointly considering constraint conditions such as the visible time windows between distributed satellite systems and user satellites in MEO and LEO, the residual resources of satellite systems and the property of user transmission tasks. Considering the number of scheduling tasks in practice,the typical PSO algorithm is modified and the proposed algorithm is verified by computer simulations.%近年来随着我国在轨遥感卫星数量的不断增加,对当前中继星系统的数传能力提出了更高的要求。在卫星平台载荷能力受限的情况下,分布式卫星系统成为大幅提升中继星系统性能的可行方案。针对分布式卫星系统的数传任务调度问题,综合考虑系统与中低轨航天器用户之间的可见时间窗口、卫星剩余资源及数传任务属性等约束条件,提出了基于粒子群优化( PSO)的多星多任务数传调度方法。根据实际中继系统任务量级对经典 PSO 算法进行了改进,并通过计算机仿真验证了改进算法的有效性。

  14. SaVi: satellite constellation visualization

    Wood, Lloyd


    SaVi, a program for visualizing satellite orbits, movement, and coverage, is maintained at the University of Surrey. This tool has been used for research in academic papers, and by industry companies designing and intending to deploy satellite constellations. It has also proven useful for demonstrating aspects of satellite constellations and their geometry, coverage and movement for educational and teaching purposes. SaVi is introduced and described briefly here.

  15. A low cost data logging system with satellite transmission capabilities

    Desa, E.S.; DeSa, E.J.; Desai, R.G.P.

    satellite navigator, deep sea echosounder, and a magnetometer on board a chartered research vessel. A novel data logger design was implemented with the extra option of transmitting logged data through the ships INMARSAT approved satellite terminal...

  16. Advanced ISDN satellite designs and experiments

    Pepin, Gerard R.


    The research performed by GTE Government Systems and the University of Colorado in support of the NASA Satellite Communications Applications Research (SCAR) Program is summarized. Two levels of research were undertaken. The first dealt with providing interim services Integrated Services Digital Network (ISDN) satellite (ISIS) capabilities that accented basic rate ISDN with a ground control similar to that of the Advanced Communications Technology Satellite (ACTS). The ISIS Network Model development represents satellite systems like the ACTS orbiting switch. The ultimate aim is to move these ACTS ground control functions on-board the next generation of ISDN communications satellite to provide full-service ISDN satellite (FSIS) capabilities. The technical and operational parameters for the advanced ISDN communications satellite design are obtainable from the simulation of ISIS and FSIS engineering software models of the major subsystems of the ISDN communications satellite architecture. Discrete event simulation experiments would generate data for analysis against NASA SCAR performance measure and the data obtained from the ISDN satellite terminal adapter hardware (ISTA) experiments, also developed in the program. The Basic and Option 1 phases of the program are also described and include the following: literature search, traffic mode, network model, scenario specifications, performance measures definitions, hardware experiment design, hardware experiment development, simulator design, and simulator development.

  17. 移动卫星网络中卫星切换调度研究%Research on the Handover Scheduling in Mobile Satellite Communication Networks

    吴兆峰; 胡谷雨; 金凤林


    针对卫星切换调度问题,提出了一种最大服务时长切换调度算法。该算法利用了现有的GPS基础设施和卫星网络中卫星的多样性(即在任意时刻多颗卫星覆盖相同的区域),减少了用户在通信过程中的切换次数,从而最终降低了用户的掉话率,实现了用户在低轨( LEO)卫星网络中实时高效的切换。在Iridium卫星网络中的仿真结果验证了该算法的有效性。%A new satellite handover scheduling algorithm based on the maximum residual service time was proposed. The algorithm exploits both global positioning system ( GPS) infrastructure and satellite diversi-ty, providing a simple and real-time handover management in low earth orbit ( LEO) satellite networks to minimize the expected number of satellite handovers. It reduces the users' call drop probability ultimate-ly. Simulations were carried out on the typical Iridium satellite network and the simulation results corrob-orate the advantages gained by the proposed algorithm.

  18. China Satellite Navigation Conference

    Liu, Jingnan; Fan, Shiwei; Wang, Feixue


    These Proceedings present selected research papers from CSNC2016, held during 18th-20th May in Changsha, China. The theme of CSNC2016 is Smart Sensing, Smart Perception. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2016, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  19. China Satellite Navigation Conference

    Liu, Jingnan; Yang, Yuanxi; Fan, Shiwei; Yu, Wenxian


    These proceedings present selected research papers from CSNC2017, held during 23th-25th May in Shanghai, China. The theme of CSNC2017 is Positioning, Connecting All. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2017, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  20. Future communications satellite applications

    Bagwell, James W.


    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.

  1. HETE Satellite Power Subsystem


    The HETE (High-Energy Transient Experiment) satellite a joint project between MIT's Center for Space Research and AeroAstro. is a high-energy gamma-ray burst/X-Ray/UV observatory platform. HETE will be launched into a 550 km circular orbit with an inclination of 37.7°, and has a design lifetime of 18 months. This paper presents a description of the spacecraft's power subsystem, which collects, regulates, and distributes power to the experiment payload modules and to the various spacecraft sub...

  2. Research on Modeling of the Agile Satellite Using a Single Gimbal Magnetically Suspended CMG and the Disturbance Feedforward Compensation for Rotors

    Ning Yan


    Full Text Available The magnetically suspended Control Moment Gyroscope (CMG has the advantages of long-life, micro-vibration and being non-lubricating, and is the ideal actuator for agile maneuver satellite attitude control. However, the stability of the rotor in magnetic bearing and the precision of the output torque of a magnetically suspended CMG are affected by the rapid maneuvers of satellites. In this paper, a dynamic model of the agile satellite including a magnetically suspended single gimbal control moment gyroscope is built and the equivalent disturbance torque effected on the rotor is obtained. The feedforward compensation control method is used to depress the disturbance on the rotor. Simulation results are given to show that the rotor displacement is obviously reduced.

  3. Satellite Communications Using Commercial Protocols

    Ivancic, William D.; Griner, James H.; Dimond, Robert; Frantz, Brian D.; Kachmar, Brian; Shell, Dan


    NASA Glenn Research Center has been working with industry, academia, and other government agencies in assessing commercial communications protocols for satellite and space-based applications. In addition, NASA Glenn has been developing and advocating new satellite-friendly modifications to existing communications protocol standards. This paper summarizes recent research into the applicability of various commercial standard protocols for use over satellite and space- based communications networks as well as expectations for future protocol development. It serves as a reference point from which the detailed work can be readily accessed. Areas that will be addressed include asynchronous-transfer-mode quality of service; completed and ongoing work of the Internet Engineering Task Force; data-link-layer protocol development for unidirectional link routing; and protocols for aeronautical applications, including mobile Internet protocol routing for wireless/mobile hosts and the aeronautical telecommunications network protocol.

  4. Satellite data compression

    Huang, Bormin


    Satellite Data Compression covers recent progress in compression techniques for multispectral, hyperspectral and ultra spectral data. A survey of recent advances in the fields of satellite communications, remote sensing and geographical information systems is included. Satellite Data Compression, contributed by leaders in this field, is the first book available on satellite data compression. It covers onboard compression methodology and hardware developments in several space agencies. Case studies are presented on recent advances in satellite data compression techniques via various prediction-

  5. Trends in communications satellites

    Curtin, Denis J


    Trends in Communications Satellites offers a comprehensive look at trends and advances in satellite communications, including experimental ones such as NASA satellites and those jointly developed by France and Germany. The economic aspects of communications satellites are also examined. This book consists of 16 chapters and begins with a discussion on the fundamentals of electrical communications and their application to space communications, including spacecraft, earth stations, and orbit and wavelength utilization. The next section demonstrates how successful commercial satellite communicati

  6. TUBSAT-1, satellite technology for educational purposes

    Ginati, A.


    TUBSAT-1 (Technical University of Berlin Satellite) is an experimental low-cost satellite within the NASA Get Away Special (GAS) program. This project is being financed by the German BMFT (Federal Ministry for Research and Technology), mainly for student education. The dimensions and weight are determined by GAS requirements and the satellite will be ejected from the space shuttle into an approximately 300-km circular orbit. It is a sun/star oriented satellite with an additional spin stabilization mode. The first planned payload is to be used for observing flight paths of migratory birds from northern Europe to southern Africa and back.

  7. Satellite Remote Sensing in Offshore Wind Energy

    Hasager, Charlotte Bay; Badger, Merete; Astrup, Poul


    Satellite remote sensing of ocean surface winds are presented with focus on wind energy applications. The history on operational and research-based satellite ocean wind mapping is briefly described for passive microwave, scatterometer and synthetic aperture radar (SAR). Currently 6 GW installed...

  8. Nanosatellite swarm support for larger satellites

    Verhoeven, Chris; Engelen, Steven; Noroozi, Arash; Bentum, Marinus Jan; Sundaramoorthy, Prem; Meijer, Robert


    Nano-satellites are small (less than 10 kg) and low cost satellites of which quite a number has been launched the last few years, mostly as university educational or research projects. The development of professional scientific and commercial applications is still in its infancy and there are only

  9. Nanosatellite swarm support for larger satellites

    Verhoeven, Chris; Engelen, Steven; Noroozi, Arash; Sundaramoorthy, Prem; Bentum, Mark; Meijer, Robert


    Nano-satellites are small (less than 10 kg) and low cost satellites of which quite a number has been launched the last few years, mostly as university educational or research projects. The development of professional scientific and commercial applications is still in its infancy and there are only f

  10. Research progress of Group Key Management for Multi-layered Satellite Networks%多层卫星网络组密钥管理研究进展

    余哲赋; 周海刚; 吴兆峰; 朱晓薇


    为保证多层卫星网络的通信安全,使用组密钥对通信进行加密是一个普遍而有效的方法。设计适合卫星网络的组密钥管理方案,是确保卫星通信安全的关键问题之一。本文介绍了多层卫星网络的概况,对现有多层卫星网络组密钥管理方案进行了分类,详细分析了几类典型的组密钥管理方案,指出了存在的问题,并对以后的研究方向作了展望。%Encrypting the contents of communication by using group key is an universal and effective method to ensure the security of communication in the Multi-layered satellite networks,and the design of a group key management scheme suitable for satellite networks is one of the key problems.This article provides an introduction of multi-layered satellite networks and classifies the routing protocols.This paper details several existing typical group key management schemes,and points out the corresponding disadvantages.The trends of group key management for multi-layered satellite networks are analyzed briefly.

  11. Solar photovoltaic research and development program of the Air Force Aero Propulsion Laboratory. [silicon solar cell applicable to satellite power systems

    Wise, J.


    Progress is reported in the following areas: laser weapon effects, solar silicon solar cell concepts, and high voltage hardened, high power system technology. Emphasis is placed on solar cells with increased energy conversion efficiency and radiation resistance characteristics for application to satellite power systems.

  12. Equatorial dynamics observed by rocket, radar, and satellite during the CADRE/MALTED campaign 1. Programmatics and small-scale fluctuations

    Goldberg, Richard A.; Lehmacher, Gerald A.; Schmidlin, Frank J.; Fritts, David C.; Mitchell, J. D.; Croskey, C. L.; Friedrich, M.; Swartz, W. E.


    In August 1994, the Mesospheric and Lower Thermospheric Equatorial Dynamics (MALTED) Program was conducted from the Alca‸ntara rocket site in northeastern Brazil as part of the International Guará Rocket Campaign to study equatorial dynamics, irregularities, and instabilities in the ionosphere. This site was selected because of its proximity to the geographic (2.3°S) and magnetic (~0.5°S) equators. MALTED was concerned with planetary wave modulation of the diurnal tidal amplitude, which exhibits considerable amplitude variability at equatorial and subtropical latitudes. Our goals were to study this global modulation of the tidal motions where tidal influences on the thermal structure are maximum, to study the interaction of these tidal structures with gravity waves and turbulence at mesopause altitudes, and to gain a better understanding of dynamic influences and variability on the equatorial middle atmosphere. Four (two daytime and two nighttime) identical Nike-Orion payloads designed to investigate small-scale turbulence and irregularities were coordinated with 20 meteorological falling-sphere rockets designed to measure temperature and wind fields during a 10-day period. These in situ measurements were coordinated with observations of global-scale mesospheric motions that were provided by various ground based radars and the Upper Atmosphere Research Satellite (UARS) through the Coupling and Dynamics of Regions Equatorial (CADRE) campaign. The ground-based observatories included the Jicamarca radar observatory near Lima, Peru, and medium frequency (MF) radars in Hawaii, Christmas Island, and Adelaide. Since all four Nike-Orion flights penetrated and overflew the electrojet with apogees near 125 km, these flights provided additional information about the electrodynamics and irregularities in the equatorial ionospheric E region and may provide information on wave coupling between the mesosphere and the electrojet. Simultaneous with these flights, the CUPRI 50

  13. Xichang Satellite Launch Center



    Xichang Satellite Launch Center(XSLC) is mainly for geosynchronous orbit launches. The main purpose of XSLC is to launch spacecraft, such as broadcasting,communications and meteorological satellites, into geo-stationary orbit.Most of the commercial satellite launches of Long March vehicles have been from Xichang Satellite Launch Center. With 20 years' development,XSLC can launch 5 kinds of launch vehicles and send satellites into geostationary orbit and polar orbit. In the future, moon exploration satellites will also be launched from XSLC.

  14. Handbook of satellite applications

    Madry, Scott; Camacho-Lara, Sergio


    The first edition of this ground breaking reference work was the most comprehensive reference source available about the key aspects of the satellite applications field. This updated second edition covers the technology, the markets, applications and regulations related to satellite telecommunications, broadcasting and networking—including civilian and military systems; precise satellite navigation and timing networks (i.e. GPS and others); remote sensing and meteorological satellite systems. Created under the auspices of the International Space University based in France, this brand new edition is now expanded to cover new innovative small satellite constellations, new commercial launching systems, innovation in military application satellites and their acquisition, updated appendices, a useful glossary and more.

  15. Satellite Eye for Galathea 3. Annual report 2006

    Hasager, Charlotte Bay; Sørensen, Peter; Pedersen, Leif Toudal

    The Satellite Eye for Galathea 3 project is collecting satellite images from many satellites and, in particular, from the European ENVISAT satellite along the Galathea 3 global route. The expedition takes place from 11 August 2006 to 27 April 2007. Prior to the expedition several satellite images...... were collected from locations along the planned route. During the expedition large amounts of satellite images are collected and stored in a database. Most images can be viewed online through Google Earth along with the ship observations in near-real-time. This means that researchers onboard the ship...

  16. Galileo satellite antenna modeling

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


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

  17. Landsat—Earth observation satellites



    Since 1972, Landsat satellites have continuously acquired space-based images of the Earth’s land surface, providing data that serve as valuable resources for land use/land change research. The data are useful to a number of applications including forestry, agriculture, geology, regional planning, and education. Landsat is a joint effort of the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA). NASA develops remote sensing instruments and the spacecraft, then launches and validates the performance of the instruments and satellites. The USGS then assumes ownership and operation of the satellites, in addition to managing all ground reception, data archiving, product generation, and data distribution. The result of this program is an unprecedented continuing record of natural and human-induced changes on the global landscape.

  18. Small satellites and their regulation

    Jakhu, Ram S


    Since the launch of UoSat-1 of the University of Surrey (United Kingdom) in 1981, small satellites proved regularly to be useful, beneficial, and cost-effective tools. Typical tasks cover education and workforce development, technology demonstration, verification and validation, scientific and engineering research as well as commercial applications. Today the launch masses range over almost three orders of magnitude starting at less than a kilogram up to a few hundred kilograms, with budgets of less than US$ 100.00 and up to millions within very short timeframes of sometimes less than two years. Therefore each category of small satellites provides specific challenges in design, development and operations. Small satellites offer great potentials to gain responsive, low-cost access to space within a short timeframe for institutions, companies, regions and countries beyond the traditional big players in the space arena. For these reasons (particularly the low cost of construction, launch and operation), small (m...

  19. Research, planning, design and development of selected components, subsystems and systems for the Students for the Exploration and Development of Space Satellite (SEDSAT)

    Wingo, Dennis


    The work proposed in this task order was successfully accomplished. This is reflected in the approval by three NASA centers of the SEDSAT satellite to fly as a payload on the shuttle. All documentation necessary for evaluation of the satellite as a Shuttle payload was submitted and approved by the appropriate safety boards. The SEASIS instrument was demonstrated to work and its inclusion as a SEDSAT payload was accomplished in the task period. Finally, the SEDSAT interface to the NASA GSFC PES was approved by MSFC and GSFC with no substantive issues outstanding. As of the end of the contract date all milestones were met. However the NASA MSFC SEDS program was cancelled by the center. Since that time SEDSAT has gone on to be manifested on a Delta vehicle.

  20. Small Satellite Transceiver for Launch Vehicles Project

    National Aeronautics and Space Administration — NAL Research Corporation proposes to develop a small, light-weight, low-cost transceivers capable of establishing satellite communications links for telemetry and...

  1. Small Satellite Transceiver for Launch Vehicles Project

    National Aeronautics and Space Administration — NAL Research Corporation proposes to develop a small, light-weight, low-cost transceivers capable of establishing satellite communications links for telemetry and...

  2. Research on Rake Receiving Performance Based on Multi-satellite Diversity%基于多星分集的Rake接收性能研究



    In LEO satellite mobile communication system of CDMA,there are at least two satellites over the gateway station simul-taneously.According to this feature,Rake receiver is studied by considering the channel characteristics of LEO satellite communication systems.In order to track in real time the change of the channel,a multipath combining scheme based on fast convergence LMS algorithm (FC-LMS) is proposed.The simulation results show that the multi-satellite transmits diversity and Rake receiver can be used to reduce the BER and improve the performance of system.%在低轨卫星CDMA移动通信系统中,信关站的上空会同时存在至少2颗卫星。针对这一特点,综合考虑低轨卫星通信信道的特性,研究分析了在信关站端采用的多星分集和Rake接收技术,提出了一种基于快速收敛LMS算法( FC-LMS)的多径合并方案,实现对信道变化的实时跟踪。仿真结果表明,在信关站端采用多星发送分集方案与Rake接收技术,可以有效降低系统误码率,改善系统性能。

  3. Satellite-Delivered Learning.

    Arnall, Gail C.


    Discusses the application of satellite information delivery to training. Describes a new trend, horizontal programming. Also discusses vertical programming and in-house production of training materials. Lists vendors of satellite-based training. (CH)

  4. GPS Satellite Simulation Facility

    Federal Laboratory Consortium — The GPS satellite simulation facility consists of a GPS satellite simulator controlled by either a Silicon Graphics Origin 2000 or PC depending upon unit under test...

  5. China's Recoverable Satellites

    Tang Boehang


    @@ By the end of 2006, China had launched 24 recoverable satellites (FSW) in total. Among them, 23 were launched successfully, of which all but one were successfully recovered. Recoverable satellites launched by China are listed in Table 1.

  6. Satellite Tags- Hawaii EEZ

    National Oceanic and Atmospheric Administration, Department of Commerce — Satellite tagging was implemented in 2013. Satellite tagging is conducted using a Dan Inject air rifle and deployment arrows designed by Wildlife Computers. Two...

  7. Research on the system performance evaluation of minimum-shift keying in uplink ground-to-satellite with gamma-gamma distribution

    Wang, Yi; Zhang, Ao; Ma, Jing


    Minimum-shift keying (MSK) has the advantages of constant envelope, continuous phase, and high spectral efficiency, and it is applied in radio communication and optical fiber communication. MSK modulation of coherent detection is proposed in the ground-to-satellite laser communication system; in addition, considering the inherent noise of uplink, such as intensity scintillation and beam wander, the communication performance of the MSK modulation system with coherent detection is studied in the uplink ground-to-satellite laser. Based on the gamma-gamma channel model, the closed form of bit error rate (BER) of MSK modulation with coherent detection is derived. In weak, medium, and strong turbulence, the BER performance of the MSK modulation system is simulated and analyzed. To meet the requirements of the ground-to-satellite coherent MSK system to optimize the parameters and configuration of the transmitter and receiver, the influence of the beam divergence angle, the zenith angle, the transmitter beam radius, and the receiver diameter are studied.

  8. Satellite communication engineering

    Kolawole, Michael Olorunfunmi


    An undeniably rich and thorough guide to satellite communication engineering, Satellite Communication Engineering, Second Edition presents the fundamentals of information communications systems in a simple and succinct way. This book considers both the engineering aspects of satellite systems as well as the practical issues in the broad field of information transmission. Implementing concepts developed on an intuitive, physical basis and utilizing a combination of applications and performance curves, this book starts off with a progressive foundation in satellite technology, and then moves on

  9. 基于资源三号卫星影像的立体测图技术研究%Research on Stereo Mapping Technology Based on ZY-3 Satellite Imagery

    陈世培; 刘薇; 董爵兰; 赵淑玲


    随着国产卫星影像资源的日益丰富,基于国产卫星影像的应用与研究也成为测绘相关行业竞相探究的焦点。本文以此为背景开展研究,总体目标是以资源三号国产卫星遥感影像为影像源,利用多种基础资料(控制资料、地形图数据、调绘成果、DEM成果、DOM成果等),应用区域网平差立体模型成果通过各种成果精度比对,得出资三影像成果应用范围,对基础测绘项目的开展具有指导性作用。%With the development of domestic satellite imageries , the application and research on domestic satellite imageries have also become the focus of surveying and mapping industry .In this paper , using ZY-3 satellite imagery and other basic data ( control data , topographic data , painting achievement , DEM achievement , DOM achievement ) , DOM, DEM and DLG are manufactured based on the result of block adjustment .The accuracy of results is compared and the application range of ZY -3 satellite imagery achievement is obtained.It provides a guiding role in basic mapping projects .

  10. Taiyuan Satellite Launch Center



    There are three major space launch bases in China, the Jiuquan Satellite Launch Center,the Taiyuan Satellite Launch Center and the Xichang Satellite Launch Center. All the three launch centers are located in sparsely populated areas where the terrain is even and the field of vision is broad. Security, transport conditions and the influence of the axial rotation

  11. Geodetic Secor Satellite


    simple, and had low-power lem. 17 14. Satellite Orientation . The satellite was designed to maintain a constant relationship between the antenna...the same satellite orientation . Further considerations were Th oscillations, however, when higher orbital ranges (500-2500 nautical miles) -, 3 a

  12. TC-2 Satellite Delivered


    On April 18, 2005, TC-2, the second satellite of Double Star Program (DSP), which was jointly developed by CNSA and ESA, was approved to be delivered to the user after the on-board test and trial operation. The satellite is working well and the performance can meet the user's need. The satellite has collected large amount of valuable scientific data

  13. Astronomy from satellite clusters

    Stachnik, R.; Labeyrie, A.


    Attention is called to the accumulating evidence that giant space telescopes, comprising a number of separate mirrors on independent satellites, are a realistic prospect for providing research tools of extraordinary power. The ESA-sponsored group and its counterpart in the US have reached remarkably similar conclusions regarding the basic configuration of extremely large synthetic-aperture devices. Both share the basic view that a cluster of spacecraft is preferable to a single monolithic structure. The emphasis of the US group has been on a mission that sweeps across as many sources as possible in the minimum time; it is referred to as SAMSI (Spacecraft Array for Michelson Spatial Interferometry). The European group has placed more emphasis on obtaining two-dimensional images. Their system is referred to as TRIO because, at least initially, it involves three independent systems. Detailed descriptions are given of the two systems.

  14. 基于卫星信道的MAPSK调制方法研究%Research Based on Satellite Channel Modulation Method of MAPSK

    郭淑霞; 韩前进


    针对宽带卫星通信中信道降雨衰落的非线性特性,研究了多进制幅度移相键控MAPSK调制方法,该方法通过对调制信号星座采取非对称的优化设计方法,有效抵抗了降雨衰落的非线性影响,提高了卫星通信的可靠性,并对该方法进行了仿真验证;仿真结果表明:在基于Mie散射理论建立的雨衰信道模型下,当信噪比大于20dB时,16APSK的误码率明显低于16QAM的误码率,因此在受雨衰影响的卫星通信信道中,16 APSK调制方法与16QAM调制方法相比可以有效地抵抗降雨衰落的影响.%Broadband satellite communications for the decline of Channel rainfall nonlinearity of the multi —band amplitude modulated phase shift keying MAPSK method by asymmetric modulation signal constellation design optimization, effective against a decline of non — rainfall linear effect, improve the reliability of satellite communications, and simulation. Simulation results show that: in the theory of scattering of rain attenuation based on channel conditions, when the signal to noise ratio greater than 20dB when, 16APSK 16QAM bit error rate was significantly lower than the error rate, and therefore affected by rain attenuation of satellite communication channel, 16APSK coded modulation with 16QAM modulation can effectively resist the rain compared to the impact of the decline.

  15. Meteorological satellite systems

    Tan, Su-Yin


    “Meteorological Satellite Systems” is a primer on weather satellites and their Earth applications. This book reviews historic developments and recent technological advancements in GEO and polar orbiting meteorological satellites. It explores the evolution of these remote sensing technologies and their capabilities to monitor short- and long-term changes in weather patterns in response to climate change. Satellites developed by various countries, such as U.S. meteorological satellites, EUMETSAT, and Russian, Chinese, Japanese and Indian satellite platforms are reviewed. This book also discusses international efforts to coordinate meteorological remote sensing data collection and sharing. This title provides a ready and quick reference for information about meteorological satellites. It serves as a useful tool for a broad audience that includes students, academics, private consultants, engineers, scientists, and teachers.

  16. Theory of geostationary satellites

    Zee, Chong-Hung


    Geostationary or equatorial synchronous satellites are a daily reminder of our space efforts during the past two decades. The nightly television satellite weather picture, the intercontinental telecommunications of television transmissions and telephone conversations, and the establishrnent of educational programs in remote regions on Earth are constant reminders of the presence of these satellites. As used here, the term 'geo­ stationary' must be taken loosely because, in the long run, the satellites will not remain 'stationary' with respect to an Earth-fixed reference frame. This results from the fact that these satellites, as is true for all satellites, are incessantly subject to perturbations other than the central-body attraction of the Earth. Among the more predominant pertur­ bations are: the ellipticity of the Earth's equator, the Sun and Moon, and solar radiation pressure. Higher harmonics of the Earth's potential and tidal effects also influence satellite motion, but they are of second­ order whe...

  17. Simulator design for advanced ISDN satellite design and experiments

    Pepin, Gerald R.


    This simulation design task completion report documents the simulation techniques associated with the network models of both the Interim Service ISDN (integrated services digital network) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures. The ISIS network model design represents satellite systems like the Advanced Communication Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) program, moves all control and switching functions on-board the next generation ISDN communication satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete events simulation experiments will be performed with these models using various traffic scenarios, design parameters and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

  18. The Arctic Regional Communications Small SATellite (ARCSAT)

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


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

  19. Satellite reentry predictions for the Italian civil protection authorities

    Anselmo, Luciano; Pardini, Carmen


    In just 5 months, from September 2011 to January 2012, three campaigns of reentry predictions were carried out in support of the Italian civil protection authorities. The satellites involved were UARS, ROSAT and Fobos-Grunt, which received widespread attention for the marginal risk on the ground associated with their uncontrolled reentry. From the technical point of view, the three reentry campaigns offered the occasion to compare some semi-empirical thermospheric density models under varying solar and geomagnetic activity conditions, dealing with spacecraft characterized by quite different configurations, shapes, masses and attitude control. However, what made the experience substantially different from usual reentry test campaigns was the strict interaction with the civil protection community and the public. In fact, in order to provide understandable and unambiguous information useful for civil protection planning and applications, the nominal reentry time predictions were of no use, while a particular care was devoted to the definition of appropriate reentry uncertainty windows. The attention of the civil protection authorities was focused, of course, on the Italian territory, so the relevant question for any planning was the following: given a certain uncertainty window, where and when a fragment might have crossed the national airspace and hit the ground? In order to meet this demand, during the last 3-4 days of satellite residual lifetime, reentries where simulated over Italy to obtain quite accurate ground tracks, debris swaths and air space crossing time windows associated with the critical passes over the national territory still included in the current uncertainty window. This information was updated, if needed, but remained relatively stable and accurate until the reentry, not much affected by the actual trajectory evolution due to the varying air drag. In other words, it was easy to understand for people not familiar with orbital dynamics, unambiguous

  20. Satellite Networks: Architectures, Applications, and Technologies

    Bhasin, Kul (Compiler)


    Since global satellite networks are moving to the forefront in enhancing the national and global information infrastructures due to communication satellites' unique networking characteristics, a workshop was organized to assess the progress made to date and chart the future. This workshop provided the forum to assess the current state-of-the-art, identify key issues, and highlight the emerging trends in the next-generation architectures, data protocol development, communication interoperability, and applications. Presentations on overview, state-of-the-art in research, development, deployment and applications and future trends on satellite networks are assembled.

  1. Advanced satellite communication system

    Staples, Edward J.; Lie, Sen


    The objective of this research program was to develop an innovative advanced satellite receiver/demodulator utilizing surface acoustic wave (SAW) chirp transform processor and coherent BPSK demodulation. The algorithm of this SAW chirp Fourier transformer is of the Convolve - Multiply - Convolve (CMC) type, utilizing off-the-shelf reflective array compressor (RAC) chirp filters. This satellite receiver, if fully developed, was intended to be used as an on-board multichannel communications repeater. The Advanced Communications Receiver consists of four units: (1) CMC processor, (2) single sideband modulator, (3) demodulator, and (4) chirp waveform generator and individual channel processors. The input signal is composed of multiple user transmission frequencies operating independently from remotely located ground terminals. This signal is Fourier transformed by the CMC Processor into a unique time slot for each user frequency. The CMC processor is driven by a waveform generator through a single sideband (SSB) modulator. The output of the coherent demodulator is composed of positive and negative pulses, which are the envelopes of the chirp transform processor output. These pulses correspond to the data symbols. Following the demodulator, a logic circuit reconstructs the pulses into data, which are subsequently differentially decoded to form the transmitted data. The coherent demodulation and detection of BPSK signals derived from a CMC chirp transform processor were experimentally demonstrated and bit error rate (BER) testing was performed. To assess the feasibility of such advanced receiver, the results were compared with the theoretical analysis and plotted for an average BER as a function of signal-to-noise ratio. Another goal of this SBIR program was the development of a commercial product. The commercial product developed was an arbitrary waveform generator. The successful sales have begun with the delivery of the first arbitrary waveform generator.

  2. Global satellite composites - 20 years of evolution

    Kohrs, Richard A.; Lazzara, Matthew A.; Robaidek, Jerrold O.; Santek, David A.; Knuth, Shelley L.


    For two decades, the University of Wisconsin Space Science and Engineering Center (SSEC) and the Antarctic Meteorological Research Center (AMRC) have been creating global, regional and hemispheric satellite composites. These composites have proven useful in research, operational forecasting, commercial applications and educational outreach. Using the Man computer Interactive Data System (McIDAS) software developed at SSEC, infrared window composites were created by combining Geostationary Operational Environmental Satellite (GOES), and polar orbiting data from the SSEC Data Center and polar data acquired at McMurdo and Palmer stations, Antarctica. Increased computer processing speed has allowed for more advanced algorithms to address the decision making process for co-located pixels. The algorithms have evolved from a simplistic maximum brightness temperature to those that account for distance from the sub-satellite point, parallax displacement, pixel time and resolution. The composites are the state-of-the-art means for merging/mosaicking satellite imagery.

  3. Research on the standards of indicators associated with maintain time in bidirectional beam tracking in inter-satellites optical communication links.

    Yu, Siyuan; Wu, Feng; Tan, Liying; Guo, Pengzhen; Ma, Jing


    We report on a novel technology for high-speed inter-satellites optical communication by bidirectional beam tracking. By establishing the relation between the compensation effect and the parameters of response time and overshoot situation, the stability can be well compensated simply by the control system. Thus the relation between compensation effect and maintain time can be predicted from ground tests, and the certain evaluation standard could be established to meet the requirements of system. The other critical factors, such as signal-to-noise ratio and pointing angle error, have also been considered to improve the stability. The general approach can provide us a powerful path to overcome the performance limitation of bidirectional beam tracking, which can be expected to be widely applied in Free Space optics communications in future.

  4. 低轮廓动中通天线研究现状%Research Status of Low Profile Antennas in Satellite Communication on-the-move

    李琳; 万继响


    针对目前卫星通信系统对天线性能、形式的需求,回顾了卫星移动通信中天线的应用背景和发展历程,对国内外低剖面动中通天线的类型进行了综述;详细介绍了平板阵列、一维和二维有源相控阵天线的工作原理和代表产品,分析了各自产品在具体使用环境中的技术指标及优缺点;进一步研究了低轮廓动中通天线的关键技术;最后对卫星移动通信天线的发展趋势进行了展望。%According to the requirements of antenna performance and profile in satellite communication, the background and development of antenna for satellite communications on-the-move is firstly reviewed and the type of the low profile anten-na for SOTM abroad is then described. Moreover, the plate antenna and the 1-D and 2-D electronic scanned active phased arrays are introduced in detail. The advantages as well as the shortcomings and the characteristics of these products under practical condition are analyzed. Furthermore, other key technologies about low profile antenna are presented. Finally, the development trend of the low profile antenna of SOTM is predicted.

  5. 基于卫星导航系统的高速列车定位技术研究%Research on High-speed Train Positioning Technology Based on Satellite Navigation System

    李卫东; 侯丽虹


    In this paper,we first introduce the development of a global navigation satellite system and analyze its per-formance.By combining our research results and the application of a train positioning technology that uses domestic and international satellite navigation systems,we divide the train positioning technology into four categories.Then, we comprehensively analyze the performance of the train positioning technology with respect to accuracy,effective-ness,and safety integrity;summarize the existing problems;and suggest solutions.Finally,we make recommenda-tions regarding the future development of high-speed train positioning technology based on satellite navigation.%首先,介绍全球卫星导航系统的发展状况,对比分析全球卫星导航系统性能。并结合国内外基于卫星导航系统的列车定位技术的研究成果和应用情况,将列车定位技术分为四大类。然后,从精准性、有效性、安全完整性三个方面对列车定位技术综合性能进行分析,总结其存在的问题并给出解决方法。最后对基于卫星导航的高速列车定位技术的未来发展趋势进行展望。

  6. Mobile satellite communications handbook

    Cochetti, Roger


    With a Preface by noted satellite scientist Dr. Ahmad Ghais, the Second Edition reflects the expanded user base for this technology by updating information on historic, current, and planned commercial and military satellite systems and by expanding sections that explain the technology for non-technical professionals.   The book begins with an introduction to satellite communications and goes on to provide an overview of the technologies involved in mobile satellite communications, providing basic introductions to RF Issues, power Issues, link issues and system issues. It describes

  7. Satellite communication antenna technology

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


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

  8. Methods of satellite oceanography

    Stewart, R. H.


    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.

  9. The Comparative Research of Water Body Extraction Based on Mapping Satellite-1 Imagery%基于天绘一号卫星影像的水体信息提取对比研究

    查力; 宫辉力; 胡卓玮; 杜红悦


    针对天绘一号卫星高分辨率影像,采用面向对象分类方法对怀柔水库区域进行水体信息提取,在多尺度分割的基础上,统计地物的光谱信息、形状因子和亮度均值等,建立水体信息的特征集,充分利用高分辨率的特点提取水体信息,同时选取了参数相近的SPOT和RapidEye两幅国外高分影像进行对比研究,使用相同方法进行水体提取,对实验过程和结果进行了对比分析。针对提取结果,采用野外采样和矢量图分析两种方法综合进行精度评价,根据采样数据得到的精度分别为96.97%,95.45%,92.42%,分析实验结果的矢量图,其中天绘影像水体提取面积为5537412.5㎡,SPOT 影像为5398225㎡,RapidEye影像为5053262.5㎡,对实际水域的面积覆盖分别达到了101.40%,98.85%,92.54%,天绘影像的整体精度较高,但在细节表现上较为模糊,主要误差来自于对湿地的误分。实验制定了适用于天绘影像的水体提取方法和规则,分析不同因素对分割与分类结果的影响,同时,我们比较了天绘影像与国外同级别高分影像的优劣性,为天绘影像的进一步应用提供了参考。%Mapping Satellite-1 is the first transmission-type stereo mapping satellite applied for both military and civilian in China , it is carrying with high resolution panchromatic sensor(resolution 2m) and 4-band multi-spectral sensor(resolution 10m). Based on Mapping Satellite-1 high resolution imagery, we choose Huairou Reservoir(Beijing) as the experimental zone. Object-oriented information extraction technology was used to extract water bodies, based on the result of multi-resolution segmentation, we count spectrum, appearance factor and brightness of features, after analysis and observation, then set the rules to extract water bodies. For comparative research, we also select 2 same level foreign satellite(SPOT and RapidEye) images as comparative data, use

  10. EOS Aura and Future Satellite Studies of the Ozone Layer

    Schoeberl, Mark R.


    The EOS Aura mission, launched in 2004, provides a comprehensive assessment of the stratospheric dynamics and chemistry. This talk will focus on results from Aura including the chemistry of polar ozone depletion. The data from Aura can be directly linked to UARS data to produce long term trends in stratospheric trace gases.

  11. 具有星间链路的导航星座重构研究%Research on Reconfiguration of Navigation Constellation with Inter-satellite Links

    程竟爽; 何善宝; 林益明; 谢军


    针对具有星间链路的导航星座在卫星节点或链路失效情况下的重构优化设计问题,提出了一种基于遗传算法的设计方法.首先,根据导航星座的功能需求与设计约束,建立了星座综合重构优化设计模型.其次,提出了基于遗传算法的综合优化设计方法,并根据问题特性对遗传算法的具体操作进行了修改.最后,应用该方法对Walker 24/3/2构型星座及网状星间网络在节点和链路混合故障模式下的重构进行了优化设计.结果表明,基于该方法重构后的星座与网络拓扑性能能够得到一定程度的改善,证明了方法的可行性.%An approach based on genetic algorithm is proposed to solve the optimal reconfiguration problem of navigation constellation with inter-satellite links when node or link failure has occurred.Firstly,a design model is established based on the requirements and constraints of navigation constellation.Secondly,the integrated optimization method based on genetic algorithm is developed and the practical operators are modified to adapt to characteristics of the problem.Finally,the approach is applied to the optimal reconfiguration of a mesh-shaped satellite network in the Walker 24/3/2 constellation under a mixed node and link failures.Results have shown that the constellation and topology performance after reconfiguration based on this method can be improved,thus the feasibility of the method is proved.

  12. 星载光电振荡器(OEO)实现方法研究%Research on Optoelectronic Oscillator (OEO) Technology for Satellite Payloads

    梁栋; 谭庆贵; 蒋炜; 幺周石


    文章针对未来卫星领域对高频率、低相位噪声微波本振源发展需求,提出一种适应于星载应用的光电振荡器实现方法。首先介绍了光电振荡器应用背景、技术特点及发展现状。之后详细分析了星载光电振荡器的设计方法,给出了光电振荡器的振荡阀值、产生毫米波频率、幅度数学模型等,最后对光电振荡器的相位噪声性能进行详细分析。分析表明,利用光电振荡器能够产生超低相位噪声(-163dBc/Hz @10KHz)的微波本振信号,且光电振荡器的相位噪声和振荡频率无关,星载光电振荡器为未来卫星领域提供一种可行的微波本振信号生成方法。%An optoelectronic oscillator ( OEO) method for Satellite Payloads is analyzed,which is used to meet the de-mands of aerospace for high frequency and low phase noise signal. Firstly, the application background and technology char-acteristic of the OEO are introduced. Secondly,the principle,the oscillator threshold, the frequency and the amplitude of the OEO are discussed with mathematical method. Finally, the phase noise performance of the OEO is analyzed in detail. The result shows that the OEO can generate microwave signal with high performance( -163dBc/Hz @10KHz), and the phase noise of the microwave signal is independent of the oscillator frequency. The OEO can meet the demands of microwave signal generating for satellite payloads.

  13. Research of the Satellite Accounts for Logistics'Balance Sheet%物流业资产负债表卫星账户研究



    Logistics basic statistical data and indicator current is a piece of black ,and logistics statistics system lacks the relevant indexes of the assets and liabilities .Logistics satellite account w hich based on the balance sheet can measure the total amount and structure of assets and liabilities .The key is to determine the related industry department of logistics ,then prepare the non-financial corporate balance sheets ,and stripping the assets and liabilities data of transportation ,warehousing ,postal service and trade industry . Finally ,use of the logistics adjustment coefficient to adjust the assets and liabilities data of other sectors , thus created 2003-2012 China's logistics industry's balance sheet .Assets and liabilities as the main content of logistics satellite account ,will help realize the wealth of logistics industry ,enhance the comparability of logistics industry and other industries of the national economy department .%目前,物流业的基本统计数据和指标是一片黑大陆,统计体系里缺乏物流资产和物流负债的相关指标。基于资产负债表构建的物流卫星账户可以测度物流业资产和负债的总量及结构。其关键在于确定物流相关产业部门。编制非金融企业资产负债表,并在其基础上剥离出和物流业相关的交通运输、仓储、邮政业和贸易业的资产负债数据。利用物流业调整系数对相关产业部门的资产和负债数据进行调整,从而编制了2003-2012年中国物流业资产负债表。以物流资产和负债为主要内容的物流卫星账户将有助于探清物流业的家底,增强物流业与其他国民经济产业部门的可比性。

  14. Satellite Remote Sensing in Seismology. A Review

    Andrew A. Tronin


    Full Text Available A wide range of satellite methods is applied now in seismology. The first applications of satellite data for earthquake exploration were initiated in the ‘70s, when active faults were mapped on satellite images. It was a pure and simple extrapolation of airphoto geological interpretation methods into space. The modern embodiment of this method is alignment analysis. Time series of alignments on the Earth's surface are investigated before and after the earthquake. A further application of satellite data in seismology is related with geophysical methods. Electromagnetic methods have about the same long history of application for seismology. Stable statistical estimations of ionosphere-lithosphere relation were obtained based on satellite ionozonds. The most successful current project "DEMETER" shows impressive results. Satellite thermal infra-red data were applied for earthquake research in the next step. Numerous results have confirmed previous observations of thermal anomalies on the Earth's surface prior to earthquakes. A modern trend is the application of the outgoing long-wave radiation for earthquake research. In ‘80s a new technology—satellite radar interferometry—opened a new page. Spectacular pictures of co-seismic deformations were presented. Current researches are moving in the direction of pre-earthquake deformation detection. GPS technology is also widely used in seismology both for ionosphere sounding and for ground movement detection. Satellite gravimetry has demonstrated its first very impressive results on the example of the catastrophic Indonesian earthquake in 2004. Relatively new applications of remote sensing for seismology as atmospheric sounding, gas observations, and cloud analysis are considered as possible candidates for applications.

  15. Satellites of spiral galaxies

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


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

  16. Communication satellite technology trends

    Cuccia, Louis


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

  17. Satellite Meteorology Education & Training Resources from COMET

    Abshire, W. E.; Dills, P. N.; Weingroff, M.; Lee, T. F.


    The COMET® Program ( receives funding from NOAA NESDIS as well as EUMETSAT and the Meteorological Service of Canada to support education and training in satellite meteorology. These partnerships enable COMET to create educational materials of global interest on geostationary and polar-orbiting remote sensing platforms. These materials focus on the capabilities and applications of current and next-generation satellites and their relevance to operational forecasters and other user communities. By partnering with experts from the Naval Research Laboratory, NOAA-NESDIS and its Cooperative Institutes, Meteorological Service of Canada, EUMETSAT, and other user communities, COMET stimulates greater use of satellite data observations and products. This presentation provides an overview of COMET's recent satellite education efforts in the area of polar orbiting satellites. COMET has a new module on Suomi NPP, which describes the satellite system and discusses the improvements that it is bringing to forecasting, numerical weather prediction, and environmental monitoring. COMET has also published an updated version of its module on the VIIRS instrument. "Imaging with VIIRS: A Convergence of Technologies and Experience, 2nd Edition" covers the instrument's enhanced capabilities by examining the systems that contributed to its development. Special attention is paid to the Day/Night Visible channel as VIIRS is the first instrument on a civilian satellite to image atmospheric and terrestrial features with and without moonlight. An upcoming module will exclusively focus on nighttime imaging with the VIIRS Day/Night Band (DNB). "Applications of the VIIRS Day-Night Band" will introduce the capabilities of DNB imagery to a wide audience ranging from forecasters and emergency managers to wildfire fighters and oceanographers. DNB products will be compared to traditional satellite products made from infrared data, including the "fog" product. Users will learn how DNB

  18. Design of an Oscillator for Satellite Reception

    Leong, F.H.E.H.C.


    This thesis presents research on an LC-oscillator for Ku-band (10.7-12.7GHz) satellite reception. The zero-IF receiver architecture, proposed in the joint project involving the University of Twente and NXP Research, requires a 11.7GHz quadrature oscillator that achieves a phase noise of -85dBc/Hz@10

  19. Quantitative Cloud Analysis using Meteorological Satellites

    Feijt, A.J.


    This thesis is about observations of clouds from satellite and ground based instruments. The aim is to reconstruct the three dimensional cloud distributions. This information is used both in climate research and operational meteorological applications. In climate research, cloud observations provide

  20. Scenarios and performance measures for advanced ISDN satellite design and experiments

    Pepin, Gerard R.


    Described here are the contemplated input and expected output for the Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) and Full Service ISDN Satellite (FSIS) Models. The discrete event simulations of these models are presented with specific scenarios that stress ISDN satellite parameters. Performance measure criteria are presented for evaluating the advanced ISDN communication satellite designs of the NASA Satellite Communications Research (SCAR) Program.

  1. Evaluating NOx Emissions Using Satellite Observations

    Frost, G. J.; Kim, S.; Brioude, J.; McKeen, S. A.; Trainer, M.; Heckel, A.; Hilboll, A.; Richter, A.; Burrows, J. P.; Gleason, J. F.; Boersma, K. F.; Hsie, E.; Lee, S.; Angevine, W. M.; Granier, C.; Peischl, J.; Ryerson, T. B.; Fehsenfeld, F. C.


    Atmospheric NO2 columns retrieved from satellites can provide a useful top-down assessment of bottom-up NOx emissions inventories. We present three case studies of an approach to evaluate NOx emissions at a sector level by comparing satellite retrievals to regional chemical-transport model calculations of NO2 columns. In the first example, the atmospheric impact of implementing NOx controls at eastern US power plants is demonstrated. In the second study, we use NOx monitors at western US power plants to calibrate our satellite-model comparisons. We then apply our approach to evaluate bottom-up estimates of NOx emissions from western US cities. In the third example, we validate our satellite-model approach using in-situ aircraft measurements and assess NOx emissions from power plants, cities, industrial facilities, and ports in eastern Texas. We conclude with some general insights on the usefulness of this approach and suggestions for future areas of research.

  2. Comparison of Phenomenology for Satellite Characterization

    Richmond, D.; Spoto, G.


    Techniques for improved characterization of Satellites have been an area of research for several years. Many of these approaches show great promise and have been validated using models and simulations. In this paper, multiple phenomenologies that support satellite characterization will be discussed to include: optical, radar, signals, and Infra-Red. The paper will identify satellite characteristics that could be gleaned from the various data types. Algorithms that support extracting the information will be referenced. Unique collection conditions that enable a phenomenology to yield desired data will be discussed. This paper will discuss the impact of changes to satellite characterization data types over the life of an on-orbit asset. The benefits of such information will be discussed, to include re-acquiring objects after a maneuver.

  3. Research on water ice content in Cabeus crater using the data from the microwave radiometer onboard Chang’e-1 satellite


    The existence, formation and content of water ice in the lunar permanently shaded region is one of the important questions for the current Moon study. On October 9, 2009, the LCROSS mission spacecraft impacted the Moon, and the initial result verified the existence of water on the Moon. But the study on formation and content of water ice is still under debate. The existence of water ice can change the dielectric constants of the lunar regolith, and a microwave radiometer is most sensitive to the dielectric parameters. Based on this, in this paper, the radiation transfer model is improved according to the simulation results in high frequency. Then the mixture dielectric constant models, including Odelevsky model, Wagner and landau-Lifshitz model, Clau-sius model, Gruggeman-Hanai model, etc., are analyzed and compared. The analyzing results indicate that the biggest difference occurs between Lichtenecker model and the improved Dobson model. The values estimated by refractive model are the second biggest in all the models. And the results from Odelevsky model, strong fluctuation model, Wagner and Landau –Lifshitz model, Clausius model and Bruggeman-Hanai model are very near to each other. Thereafter, the relation between volume water ice content and microwave brightness temperature is constructed with Odelevsky mixing dielectric model and the improved radiative transfer simulation, and the volume water ice content in Cabeus crater is retrieved with the data from microwave radiometer onboard Chang’e-1 satellite. The results present that the improved radiative transfer model is proper for the brightness temperature simulation of the one infinite regolith layer in high frequency. The brightness temperature in Cabeus crater is 69.93 K (37 GHz), and the corresponding volume water ice content is about 2.8%.

  4. Beginnings of Satellite Navigation

    Miljenko Solarić


    Full Text Available The first satellite navigation system called the Navy Navigation Satellite System (NNSS or TRANSIT was planned in the USA in 1958. It consisted of 5-6 artificial Earth satellites, was set in motion for the USA military in 1964, and in 1967 for civilian purposes. The frequency shift of received radio waves emitted from the satellite and caused by the Doppler effect was measured. The TRANSIT satellite speed of approaching or moving away was derived from that; the TRANSIT satellites emmited also their own coordinates. Then the ship's position was determined by an intersection of three hyperboloids, which were determined from differences of distances in three time intervals. Maintenance of this navigation system was stopped in 1996, but it is still being used in the USA Navy for exploring the ionosphere. Furthermore, results of Doppler measurements in international projects at the Hvar Observatory from 1982 and 1983. This was the first time in Croatia and the former country that the coordinates of the Hvar Observatory were determined in the unique world coordinate system WGS'72. The paper ends with a brief representation of the Tsiklon Doppler navigation system produced in the former Soviet Union, and there is a list of some of numerous produced and designed satellite navigation systems.Ključne riječi

  5. Satellite Cells in Muscular Dystrophy - Lost in Polarity.

    Chang, Natasha C; Chevalier, Fabien P; Rudnicki, Michael A


    Recent findings employing the mdx mouse model for Duchenne muscular dystrophy (DMD) have revealed that muscle satellite stem cells play a direct role in contributing to disease etiology and progression of DMD, the most common and severe form of muscular dystrophy. Lack of dystrophin expression in DMD has critical consequences in satellite cells including an inability to establish cell polarity, abrogation of asymmetric satellite stem-cell divisions, and failure to enter the myogenic program. Thus, muscle wasting in dystrophic mice is not only caused by myofiber fragility but is exacerbated by intrinsic satellite cell dysfunction leading to impaired regeneration. Despite intense research and clinical efforts, there is still no effective cure for DMD. In this review we highlight recent research advances in DMD and discuss the current state of treatment and, importantly, how we can incorporate satellite cell-targeted therapeutic strategies to correct satellite cell dysfunction in DMD.

  6. Design and analysis of the satellite laser communications network

    Ren, Pei-an; Qian, Fengchen; Liu, Qiang; Jin, Linlin


    A satellite laser communications network structure with two layers and multiple domains has been proposed, which performance has been simulated by OPENT. To simulation, we design several OPNET models of the network's components based on a satellite constellation with two layers and multiple domains, as network model, node model, MAC layer protocol and optical antenna model. The network model consists of core layer and access layer. The core network consists of four geostationary orbit (GEO) satellites which are uniformly distributed in the geostationary orbit. The access network consists of 6 low Earth orbit (LEO) satellites which is the walker delta (walk-δ) constellation with three orbit planes. In access layer, each plane has two satellites, and the constellation is stably. The satellite constellation presented for space laser network can meet the demand of coverage in the middle and low latitude by a few satellites. Also several terminal device models such as the space laser transmitter, receiver, protocol layer module and optical antenna have been designed according to the inter-satellite links in different orbits t from GEO to LEO or GEO to ground. The influence to network of different transmitting throughput, receiving throughput, network protocol and average time delay are simulated. Simulation results of network coverage, connectivity and traffic load performance in different scenes show that the satellite laser network presented by the paper can be fit for high-speed satellite communications. Such analysis can provide effective reference for the research of satellite laser networking and communication protocol.

  7. Research and Application of GEO Satellite Spot-beam Covering Algorithm%GEO卫星点波束覆盖算法的研究与应用

    董彦磊; 汪春霆; 孙巍


    GEO卫星点波束覆盖范围准确计算在实际工程应用中需求日益迫切,针对GEO卫星点波束覆盖特点,提出点波束平面覆盖和点波束球面覆盖计算方法。点波束平面覆盖计算是将地球看成一个平面利用平面几何公式计算点波束覆盖范围,点波束球面覆盖计算是将地球看成一个球体利用球面立体几何公式计算点波束覆盖范围。通过仿真、分析与比较,当点波束半功率角θ3dB较小时平面覆盖计算和球面覆盖计算精度都较高,当半功率角θ3dB较大时平面覆盖计算偏差明显增大,球面覆盖计算精度一直保持在较高水平。%Accurately calculating GEO satellite spot-beam coverage is demanded increasingly in the actual engineering applications.In view ofthe features of spot-beam coverage,this paper presents the algorithm of spot-beam plane coverage and spot-beam spherical coverage.The algorithm of spot-beam plane coverage takes the Earth as a flat to calculate spot-beam coverage with plane geometry formulas,and the algorithm of spot-beam sphere coverage takes the Earth as a sphere to calculate spot-beam coverage with three-dimensional geometry formulas.Through simulation,analysis and comparison,when the half-power angle of spot-beam is smaller,both plane coverage algorithm and spot-beam spherical coverage algorithm have high accuracy of calculation. When the half-power angle of spot-beam is bigger,the calculated deviation of spot-beam plane coverage algorithm increases significantly,however the calculation accuracy of spot-beam spherical coverage algorithm maintains at a high level.

  8. Land mobile satellite propagation measurements in Japan using ETS-V satellite

    Obara, Noriaki; Tanaka, Kenji; Yamamoto, Shin-Ichi; Wakana, Hiromitsu


    Propagation characteristics of land mobile satellite communications channels have been investigated actively in recent years. Information of propagation characteristics associated with multipath fading and shadowing is required to design commercial land mobile satellite communications systems, including protocol and error correction method. CRL (Communications Research Laboratory) has carried out propagation measurements using the Engineering Test Satellite-V (ETS-V) at L band (1.5 GHz) through main roads in Japan by a medium gain antenna with an autotracking capability. This paper presents the propagation statistics obtained in this campaign.

  9. Teamwork Reasoning and Multi-Satellite Missions

    Marsella, Stacy C.; Plaunt, Christian (Technical Monitor)


    NASA is rapidly moving towards the use of spatially distributed multiple satellites operating in near Earth orbit and Deep Space. Effective operation of such multi-satellite constellations raises many key research issues. In particular, the satellites will be required to cooperate with each other as a team that must achieve common objectives with a high degree of autonomy from ground based operations. The multi-agent research community has made considerable progress in investigating the challenges of realizing such teamwork. In this report, we discuss some of the teamwork issues that will be faced by multi-satellite operations. The basis of the discussion is a particular proposed mission, the Magnetospheric MultiScale mission to explore Earth's magnetosphere. We describe this mission and then consider how multi-agent technologies might be applied in the design and operation of these missions. We consider the potential benefits of these technologies as well as the research challenges that will be raised in applying them to NASA multi-satellite missions. We conclude with some recommendations for future work.

  10. Trends In Satellite Communication

    Poley, William A.; Stevens, Grady H.; Stevenson, Steven M.; Lekan, Jack; Arth, Clifford H.; Hollansworth, James E.; Miller, Edward F.


    Report assesses trends in satellite communication from present to year 2010. Examines restrictions imposed by limited spectrum resource and technology needs created by trends. Personal communications, orbiting switchboards, and videophones foreseen.

  11. Domestic Communication Satellites

    Horowitz, Andrew


    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)

  12. Handbook of satellite applications

    Madry, Scott; Camacho-Lara, Sergio


    Top space experts from around the world have collaborated to produce this comprehensive, authoritative, and clearly illustrated reference guide to the fast growing, multi-billion dollar field of satellite applications and space communications. This handbook, done under the auspices of the International Space University based in France, addresses not only system technologies but also examines market dynamics, technical standards and regulatory constraints. The handbook is a completely multi-disciplinary reference book that covers, in an in-depth fashion, the fields of satellite telecommunications, Earth observation, remote sensing, satellite navigation, geographical information systems, and geosynchronous meteorological systems. It covers current practices and designs as well as advanced concepts and future systems. It provides a comparative analysis of the common technologies and design elements for satellite application bus structures, thermal controls, power systems, stabilization techniques, telemetry, com...

  13. Biological satellite Kosmos-936

    Vedeshin, L. A.


    A description is given of physiological experiments performed on the biological satellite Kosmos-936. Other experiments to determine the electrostatic and dielectric responses to the effects of cosmic radiation are discussed.

  14. Small Satellite Transporter Project

    National Aeronautics and Space Administration — The primary objective is to determine whether this small satellite transporter is capable of transporting at least four 6U CubeSats is possible for a given set of...

  15. Free and open-access satellite data are key to biodiversity conservation

    Turner, W.; Rondinini, C.; Pettorelli, N.; Mora, B.; Leidner, A.K.; Szantoi, Z.; Buchanan, G.; Dech, S.; Dwyer, J.; Herold, M.; Koh, L.P.; Leimgruber, P.; Taubenboeck, H.; Wegmann, M.; Wikelski, M.; Woodcock, C.


    Satellite remote sensing is an important tool for monitoring the status of biodiversity and associated environmental parameters, including certain elements of habitats. However, satellite data are currently underused within the biodiversity research and conservation communities. Three factors have s

  16. DFH-3 Satellite Platform



    The DFH-3 satellite platform is designed and developed by China Academy of Space Technology (CAST). It is a medium capability communications satellite platform. The platform adopts threeaxis attitude stabilization control system, having solar array output power of 1.7kW by the end of its design lifetime of 8 years. Its mass is 2100kg with payload capacity of 220kg.

  17. The Archimedes satellite system

    Taylor, Stuart C.; Shurvinton, William D.


    Archimedes is a satellite system conceived by the European Space Agency (ESA) to effectively serve the European market for Mobile Radio Services (MRS). This paper describes the requirements and technical design of the Archimedes satellite system. The underlying assumptions and trade-offs behind the design are detailed and the design is compared and contrasted against alternative design solutions, both technically and economically. A path forward for the development of the system is indicated.

  18. ASTRID II satellit projekt

    Jørgensen, John Leif; Primdahl, Fritz


    The report describes the instruments developed for the Swedish micro satellite "ASTRID II". Specifications of the two instruments realized under this contract, a Stellar Compass and a CSC magnetometer are given follwed by a description of the project status and plan.......The report describes the instruments developed for the Swedish micro satellite "ASTRID II". Specifications of the two instruments realized under this contract, a Stellar Compass and a CSC magnetometer are given follwed by a description of the project status and plan....

  19. Satellite formation. II

    Harris, A. W.


    A satellite formation model is extended to include evolution of planetary ring material and elliptic orbital motion. In this model the formation of the moon begins at a later time in the growth of the earth, and a significant fraction of the lunar material is processed through a circumterrestrial debris cloud where volatiles might have been lost. Thus, the chemical differences between the earth and moon are more plausibly accounted for. Satellites of the outer planets probably formed in large numbers throughout the growth of those planets. Because of rapid inward evolution of the orbits of small satellites, the present satellite systems represent only satellites formed in the last few percent of the growths of their primaries. The rings of Saturn and Uranus are most plausibly explained as the debris of satellites disrupted within the Roche limit. Because such a ring would collapse onto the planet in the course of any significant further accretion by the planet, the rings must have formed very near or even after the conclusion of accretion.

  20. History of Satellite TV Broadcasting and Satellite Broadcasting Market in Turkey

    Mihalis KUYUCU


    Full Text Available The present study analyses the satellite broadcasting that is the first important development that emerged as a result of digitalization in communication technologies and its reflections in Turkey. As the first milestone in the globalization of television broadcasting, satellite broadcasting provided substantial contribution towards the development of the media. Satellite bro adcasting both increased the broadcasting quality and geographical coverage of the television media. A conceptual study was carried out in the first part of the study in connection with the history of satellite broadcasting in Turkey and across the world. In the research part of the study, an analysis was performed on 160 television channels that broadcast in Turkey via Turksat Satellite. Economic structure of the television channels broadcasting in Turkey via satellite was studied and an analysis was perfo rmed on the operational structure of the channels. As a result of the study, it was emphasized that the television channels broadcasting via satellite platform also use other platforms for the purpose of spreading their broadcasts and television channel ow ners make investments in different branches of the media, too. Capital owners invest in different business areas other than the media although television channels broadcasting via Turksat mostly focus on thematic broadcasting and make effort to generate ec onomic income from advertisements. Delays are encountered in the course of the convergence between the new media and television channels that broadcast only from the satellite platform and such television channels experience more economic problems than the other channels. New media and many TV broadcasting platforms emerged as a result of the developments in the communication technologies. In television broadcasting, satellite platform is not an effective platform on its own. Channels make effort to reach t o more people by using other platforms in addition to

  1. Selection of satellite constellation framework of CAPS

    HAN YanBen; MA LiHua; QIAO QiYuan; YIN ZhiQiang; AI GuoXiang


    Based on the idea of transmitting the satellite navigation and positioning system,taking the distribution and variation of the Position Dilution of Precision factor (PDOP),which is closely related with the precision of navigation and positioning,within the China area as the primary criterion,we analyze and discuss the tentative plan of constellation configuration consisting of geosynchronous orbit (GEO) communication satellites and inclined geosynchronous orbit (IGSO) satellites for the transmitting Chinese Area Positioning System (CAPS).We emphatically consider the effect on the PDOP by the three major orbit parameters including the inclination,eccentricity and right ascension of the ascending node (RAAN) of IGSO satellites,to research the strategies of the constellation configuration of CAPS through software emulation.Various constellation configurations are analyzed and compared and the results show that the constellation configuration,consisting of three IGSO communication satellites in three orbits with the same inclination as 50°,the difference in RAAN as 120°and the same "8" shaped ground track centered near 115°E and four or five GEO communication satellites within 60°E to 150°E,can satisfy the requirement that Chinese domain is availably covered end the navigation and positioning with high precision could be obtained.Three relatively excellent constellation configurations are initially suggested and some concerned issues are discussed in this work.

  2. Selection of satellite constellation framework of CAPS


    Based on the idea of transmitting the satellite navigation and positioning system, taking the distribution and variation of the Position Dilution of Precision factor (PDOP), which is closely related with the precision of navigation and positioning, within the China area as the primary criterion, we analyze and discuss the tentative plan of constellation configuration consisting of geosynchronous orbit (GEO) communication satellites and inclined geosynchronous orbit (IGSO) satellites for the transmitting Chinese Area Positioning System (CAPS). We emphatically consider the effect on the PDOP by the three major orbit parameters including the inclination, eccentricity and right ascension of the ascend- ing node (RAAN) of IGSO satellites, to research the strategies of the constellation configuration of CAPS through software emulation. Various constellation configurations are analyzed and compared and the results show that the constellation configuration, consisting of three IGSO communication satellites in three orbits with the same inclination as 50°, the difference in RAAN as 120° and the same "8" shaped ground track centered near 115°E and four or five GEO communication satellites within 60°E to 150°E, can satisfy the requirement that Chinese domain is availably covered and the navigation and positioning with high precision could be obtained. Three relatively excellent constellation configurations are initially suggested and some concerned issues are discussed in this work.

  3. Spacecraft design project: High latitude communications satellite

    Josefson, Carl; Myers, Jack; Cloutier, Mike; Paluszek, Steve; Michael, Gerry; Hunter, Dan; Sakoda, Dan; Walters, Wes; Johnson, Dennis; Bauer, Terry


    The spacecraft design project was part of AE-4871, Advanced Spacecraft Design. The project was intended to provide experience in the design of all major components of a satellite. Each member of the class was given primary responsibility for a subsystem or design support function. Support was requested from the Naval Research Laboratory to augment the Naval Postgraduate School faculty. Analysis and design of each subsystem was done to the extent possible within the constraints of an eleven week quarter and the design facilities (hardware and software) available. The project team chose to evaluate the design of a high latitude communications satellite as representative of the design issues and tradeoffs necessary for a wide range of satellites. The High-Latitude Communications Satellite (HILACS) will provide a continuous UHF communications link between stations located north of the region covered by geosynchronous communications satellites, i.e., the area above approximately 60 N latitude. HILACS will also provide a communications link to stations below 60 N via a relay Net Control Station (NCS), which is located with access to both the HILACS and geosynchronous communications satellites. The communications payload will operate only for that portion of the orbit necessary to provide specified coverage.

  4. Broadband Satellite Technologies and Markets Assessed

    Wallett, Thomas M.


    The current usage of broadband (data rate greater than 64 kilobits per second (kbs)) for multimedia network computer applications is increasing, and the need for network communications technologies and systems to support this use is also growing. Satellite technology will likely be an important part of the National Information Infrastructure (NII) and the Global Information Infrastructure (GII) in the next decade. Several candidate communications technologies that may be used to carry a portion of the increased data traffic have been reviewed, and estimates of the future demand for satellite capacity have been made. A study was conducted by the NASA Lewis Research Center to assess the satellite addressable markets for broadband applications. This study effort included four specific milestones: (1) assess the changing nature of broadband applications and their usage, (2) assess broadband satellite and terrestrial technologies, (3) estimate the size of the global satellite addressable market from 2000 to 2010, and (4) identify how the impact of future technology developments could increase the utility of satellite-based transport to serve this market.



    China on Sept. 27, 2004 launched a scientific satellite atop a Long March 2D carrier rocket from Jiuquan Satellite Launch Center in Gansu province. 10 minutes after the launch, the satellite entered a preset orbit and is running sound at the orbit. It is the 20th recoverable satellite for scientific and technological

  6. Melt onset dates for Arctic regions derived from satellite passive microwave data for 1979-2010; a comparison between the operational CDR and research level ESDR data sets

    Anderson, M. R.; Bliss, A. C.


    The rapid nature and extent of the sea ice loss during recent summers have shown the importance of monitoring melt during the spring and summer transition. Using remotely sensed brightness temperatures, snow overlying sea ice can be identified. The purpose of this presentation is to show the usefulness of the new NOAA CDR for melt onset dates and the new NASA MEaSURES ESDR for melt onset dates records. The NOAA CDR melt onset algorithm is designed as an operational algorithm and uses the daily brightness temperature differences between the 37H and 19H Ghz channels from the special sensor microwave imager (SSMI) and special sensor microwave imager and sounder (SSMIS) on board the Defense Meteorology Satellite Program (DMSP) platform for the years 1987-2007 to determine the melt onset date. The melt onset dates are archived as part of the NOAA CDR for sea ice. The NASA MEaSURES ESDR melt onset date algorithm uses the same brightness temperature differences between the 37H and 19H Ghz channels, however, a ten day window and different thresholds are used to determine melt onset dates. The ESDR melt onset dates are also calculated for the scanning multi-channel microwave sensor (SMMR) on board the NASA Nimbus-7 platform. Therefore ESDR melt onset dates are calculated from 1979-2010. Comparisons are made between the NOAA CDR melt onset date data and the NASA MEaSURES ESDR melt onset date data. For the most part, the two data sets are comparable, indicating melt occurring at roughly the same time during spring. However, there are instances when the two algorithms differ, producing different melt onset dates. The main difference occurs during the earlier part of spring when spurious brightness temperatures are observed. For example, there may be low level clouds containing liquid water passing over the area, affecting the brightness temperature data for a single day, however, there is no change in the snow crystals which the algorithm should identify as melt. To account

  7. 5th China Satellite Navigation Conference

    Jiao, Wenhai; Wu, Haitao; Lu, Mingquan


    China Satellite Navigation Conference (CSNC) 2014 Proceedings presents selected research papers from CSNC2014, held on 21-23 May in Nanjing, China. The theme of CSNC2014 is 'BDS Application: Innovation, Integration and Sharing'. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 9 topics to match the corresponding sessions in CSNC2014, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.  SUN Jiadong is the Chief Designer of the Compass/ BDS, and the Academician of Chinese Academy of Sciences (CAS); JIAO Wenhai is a researcher at China Satellite Navigation Office; WU Haitao is a professor at Navigation Headquarters, CAS; LU Mingquan is a professor at Department of Electronic Engineering of Tsinghua University.

  8. Experimental Satellite 2 Successfully Launched



    Small satellite Experimental Satellite 2 (SY-2) was launched by LM-2C launch vehicle from Xichang Satellite Launch Center on Nov. 18, 2004. Later the satellite entered the preset sun-synchronous orbit, which is 700 kilometers above the earth. The launch was the eighthmission this year by China Aerospace Science and Technology Corporation(CASC), which aims to test the technology of the satellite, conduct survey and monitoring of the land and resources and geographical environment on a trial basis.

  9. China's Meteorological Satellite Application System

    Zhang Jiashen


    @@ China's meteorological satellite program consists of five systems,namely the satellite system,the launch vehicle system,the launch center system,TT&C and the ground application system.The satellite system consists of FengYun (FY) polar orbiting series and FY geostationary series,which are launched by LM launch vehicles from Taiyan Satellite Launch Center (TSLC) and Xichang Satellite Launch Center (XSLC) respectively.

  10. Undergraduate Research Experiences in Support of Dryland Monitoring: Field and Satellite Remote Sensing of Change in Savanna Structure, Biomass, and Carbon after Prescribed Fires

    Washington-Allen, R. A.; Twidwell, D. L., Jr.; Mendieta, V. P.; Delgado, A.; Redman, B.; Trollope, W. S.; Trollope, L.; Govender, N.; Smit, I.; Popescu, S. C.; de Bruno Austin, C.; Reeves, M. C.


    The status and trend of degradation in the world’s Drylands, that support over 1.2 billion people, is unknown because monitoring & assessment has not occurred on a globally consistent basis and skilled personnel with a cultivated interest in natural resource science and management are lacking. A major monitoring dataset is the 37-year Landsat data archive that has been released free to the world, but this dataset requires persons who understand how to process and interpret this and similar datasets applicable to the desertification problem. The College of Agriculture & Life Sciences (COALS) at Texas A&M University (TAMU) has an initiative to provide undergraduates with both international and research experiences. The lead author used start-up money, USFS project funds for livestock footprint studies in the US, and seed money from COALS to 1) develop academic mentor contacts in Mozambique, Namibia, Botswana, South Africa, and Tunisia to prepare a National Science Foundation Research Experience for Undergraduates (NSF-REU) Site proposal and 2) launch a pilot REU for two TAMU undergraduate students. Mr. Delgado and Mr. Redman received lidar processing and visualization, field survey training on global positioning systems (GPS), terrestrial LIDAR, and ground penetrating radar technologies and conducted carbon change studies by collecting pre- and post-fire laser scans on experimental burn (EPB) sites in Texas and South Africa. Mr. Redman also developed GIS databases of Landsat timeseries for these EPBs and others in southern Africa. Mr. Delgado participated in the Savanna Fire Ignition Research Experiment (SavFIRE) in Kruger National Park (KNP) by collected laser scan data on 3 EPBs. He also received mentoring from Dr. Winston Trollope, a prominent fire ecologist, and Mr. Chris Austin both of Working with Fire International and Navashni Govender, KNP’s Fire Ecologist. He also was an active participant in a NASA sponsored workshop on remote sensing of global

  11. Instructional Design and Adaptation Issues in Distance Learning Via Satellite.

    Thach, Liz


    Discusses a qualitative research study conducted in a distance-learning environment using satellite delivery. Describes changes in instructional design and adaptation issues which faculty and professionals involved in satellite-delivery learning situations used to be successful. (Author/AEF)

  12. A decade of ERS satellite orbits and altimetry

    Scharroo, R.


    The First European Remote Sensing Satellite, ERS-1, was launched in July 1991, fol- lowed by ERS-2 in April 1995. Both satellites carry a radar altimeter to serve oper- ational applications and scientific research in the fields of geodesy, oceanography, glaciology and meteorology. Together, the sate

  13. Plan of advanced satellite communications experiment using ETS-VI

    Shiomi, Tadashi


    Communications Research Laboratory (CRL, Ministry of Posts and Telecommunications, Japan) has been engaged in development of three advanced satellite communication payloads aiming at experiments by Japan's 2-ton class Engineering Test Satellite VI (ETS-VI) which is to be launched in H-II rocket by NASDA in August 1992. CRL's three experimental systems are: (1) S-band inter-satellite communications; (2) millimeter-wave inter-satellite and personal-satellite communications; and (3) optical inter-satellite communications. CRL develops experimental optical communication system with telescope of 75 mm diameter which has gimbal mirror beam pointing/tracking mechanism. The onboard system has fundamental optical communication functions with laser diode transmitter of wavelength 0.83 micron, laser beam point-ahead mechanism, receiver of wavelength 0.51 micron, modulation/demodulation subsystem, and so on.

  14. Use of satellite natural vibrations to improve performance of free-space satellite laser communication.

    Arnon, S


    In some of the future laser communication satellites, it is plausible to assume that tracking and communication receivers will use the same detector array. The reason for dual use of the detector is to design simpler and less expensive satellites. Satellites vibrate continually because of their subsystems and environmental sources. The vibrations cause nonuniform spreading of the received energy on the detector array. In view of this, the information from the tracking system is used to adapt individually the communication signal gain of each of the detectors in the array. This adaptation of the gains improves communication system performance. It is important to emphasize that the communication performance improvement is achieved only by gain adaptation. Any additional vibrations decrease the tracking and laser pointing system performances, which decrease the return communication performances (two-way communication). A comparison of practical communication systems is presented. The novelty of this research is the utilization of natural satellite vibrations to improve the communication system performance.

  15. Solar Power Satellites

    Flournoy, Don M


    Communication satellites are a $144 billion industry. Is there any space-based industry that could possibly beat that market? 'Solar Power Satellites' shows why and how the space satellite industry will soon begin expanding its market from relaying signals to Earth to generating energy in space and delivering it to the ground as electricity. In all industrialized nations, energy demand is growing exponentially. In the developing world, the need for energy is as basic as food and water. The Sun's energy is available everywhere, and it is non-polluting. As business plans demonstrate its technical feasibility, commercial potential, and environmental acceptability, every country on Earth will look to space for the power it needs.

  16. Geostationary satellites collocation

    Li, Hengnian


    Geostationary Satellites Collocation aims to find solutions for deploying a safe and reliable collocation control. Focusing on the orbital perturbation analysis, the mathematical foundations for orbit and control of the geostationary satellite are summarized. The mathematical and physical principle of orbital maneuver and collocation strategies for multi geostationary satellites sharing with the same dead band is also stressed. Moreover, the book presents some applications using the above algorithms and mathematical models to help readers master the corrective method for planning station keeping maneuvers. Engineers and scientists in the fields of aerospace technology and space science can benefit from this book. Hengnian Li is the Deputy Director of State Key Laboratory of Astronautic Dynamics, China.

  17. ESA's satellite communications programme

    Bartholome, P.


    The developmental history, current status, and future plans of the ESA satellite-communications programs are discussed in a general survey and illustrated with network diagrams and maps. Consideration is given to the parallel development of national and European direct-broadcast systems and telecommunications networks, the position of the European space and electronics industries in the growing world market, the impact of technological improvements (both in satellite systems and in ground-based networks), and the technological and commercial advantages of integrated space-terrestrial networks. The needs for a European definition of the precise national and international roles of satellite communications, for maximum speed in implementing such decisions (before the technology becomes obsolete), and for increased cooperation and standardization to assure European equipment manufacturers a reasonable share of the market are stressed.

  18. AVS on satellite

    Zhao, Haiwu; Wang, Guozhong; Hou, Gang


    AVS is a new digital audio-video coding standard established by China. AVS will be used in digital TV broadcasting and next general optical disk. AVS adopted many digital audio-video coding techniques developed by Chinese company and universities in recent years, it has very low complexity compared to H.264, and AVS will charge very low royalty fee through one-step license including all AVS tools. So AVS is a good and competitive candidate for Chinese DTV and next generation optical disk. In addition, Chinese government has published a plan for satellite TV signal directly to home(DTH) and a telecommunication satellite named as SINO 2 will be launched in 2006. AVS will be also one of the best hopeful candidates of audio-video coding standard on satellite signal transmission.

  19. Satellite Control Laboratory

    Wisniewski, Rafal; Bak, Thomas


    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three......-axis magnetometer, three piezoelectric gyros, and four reaction wheels in a tetrahedron configuration. The operation of the spacecraft is fully autonomous. The data flow between the transducers and the onboard computer placed physically outside the satellite is provided by a radio link. The purpose...

  20. GPS satellite surveying

    Leick, Alfred; Tatarnikov, Dmitry


    THE MOST COMPREHENSIVE, UP-TO-DATE GUIDE ON GPS TECHNOLOGY FOR SURVEYING Three previous editions have established GPS Satellite Surveying as the definitive industry reference. Now fully updated and expanded to reflect the newest developments in the field, this Fourth Edition features cutting-edge information on GNSS antennas, precise point positioning, real-time relative positioning, lattice reduction, and much more. Expert authors examine additional tools and applications, offering complete coverage of geodetic surveying using satellite technologies. The past decade has seen a major evolut

  1. Declassified intelligence satellite photographs



    Recently declassified photographs from spy satellites are an important addition to the record of the Earth?s land surface held by the U.S. Geological Survey (USGS). More than 800,000 high-resolution photos taken between 1959 through 1972 were made available by Executive Order of the President. The collection is held at the USGS EROS Data Center, near Sioux Falls, S. Dak., and are offered for public sale. For some purposes in earth science studies, these photos extend the record of changes in the land surface another decade back in time from the advent of the Landsat earth-observing satellite program.

  2. Oceanography from satellites

    Wilson, W. S.


    It is pointed out that oceanographers have benefited from the space program mainly through the increased efficiency it has brought to ship operations. For example, the Transit navigation system has enabled oceanographers to compile detailed maps of sea-floor properties and to more accurately locate moored subsurface instrumentation. General descriptions are given of instruments used in satellite observations (altimeter, color scanner, infrared radiometer, microwave radiometer, scatterometer, synthetic aperture radar). It is pointed out that because of the large volume of data that satellite instruments generate, the development of algorithms for converting the data into a form expressed in geophysical units has become especially important.

  3. Satellite oceanography - The instruments

    Stewart, R. H.


    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.

  4. AO corrected satellite imaging from Mount Stromlo

    Bennet, F.; Rigaut, F.; Price, I.; Herrald, N.; Ritchie, I.; Smith, C.


    The Research School of Astronomy and Astrophysics have been developing adaptive optics systems for space situational awareness. As part of this program we have developed satellite imaging using compact adaptive optics systems for small (1-2 m) telescopes such as those operated by Electro Optic Systems (EOS) from the Mount Stromlo Observatory. We have focused on making compact, simple, and high performance AO systems using modern high stroke high speed deformable mirrors and EMCCD cameras. We are able to track satellites down to magnitude 10 with a Strehl in excess of 20% in median seeing.

  5. A Space Based Solar Power Satellite System

    Engel, J. M.; Polling, D.; Ustamujic, F.; Yaldiz, R.; et al.


    (SPoTS) supplying other satellites with energy. SPoTS is due to be commercially viable and operative in 2020. of Technology designed the SPoTS during a full-time design period of six weeks as a third year final project. The team, organized according to the principles of systems engineering, first conducted a literature study on space wireless energy transfer to select the most suitable candidates for use on the SPoTS. After that, several different system concepts have been generated and evaluated, the most promising concept being worked out in greater detail. km altitude. Each SPoTS satellite has a 50m diameter inflatable solar collector that focuses all received sunlight. Then, the received sunlight is further redirected by means of four pointing mirrors toward four individual customer satellites. A market-analysis study showed, that providing power to geo-stationary communication satellites during their eclipse would be most beneficial. At arrival at geo-stationary orbit, the focused beam has expended to such an extent that its density equals one solar flux. This means that customer satellites can continue to use their regular solar arrays during their eclipse for power generation, resulting in a satellite battery mass reduction. the customer satellites in geo-stationary orbit, the transmitted energy beams needs to be pointed with very high accuracy. Computations showed that for this degree of accuracy, sensors are needed, which are not mainstream nowadays. Therefore further research must be conducted in this area in order to make these high-accuracy-pointing systems commercially attractive for use on the SPoTS satellites around 2020. Total 20-year system lifetime cost for 18 SPoT satellites are estimated at approximately USD 6 billion [FY2001]. In order to compete with traditional battery-based satellite power systems or possible ground based wireless power transfer systems the price per kWh for the customer must be significantly lower than the present one

  6. JPSS Preparations at the Satellite Proving Ground for Marine, Precipitation, and Satellite Analysis

    Folmer, M. J.; Berndt, E.; Clark, J.; Orrison, A.; Kibler, J.; Sienkiewicz, J. M.; Nelson, J. A., Jr.; Goldberg, M.


    The National Oceanic and Atmospheric Administration (NOAA) Satellite Proving Ground (PG) for Marine, Precipitation, and Satellite Analysis (MPS) has been demonstrating and evaluating Suomi National Polar-orbiting Partnership (S-NPP) products along with other polar-orbiting satellite platforms in preparation for the Joint Polar Satellite System - 1 (JPSS-1) launch in March 2017. The first S-NPP imagery was made available to the MPS PG during the evolution of Hurricane Sandy in October 2012 and has since been popular in operations. Since this event the MPS PG Satellite Liaison has been working with forecasters on ways to integrate single-channel and multispectral imagery from the Visible Infrared Imaging Radiometer Suite (VIIRS), the Moderate Resolution Imaging Spectroradiometer (MODIS), and the Advanced Very High Resolution Radiometer (AVHRR)into operations to complement numerical weather prediction and geostationary satellite savvy National Weather Service (NWS) National Centers. Additional unique products have been introduced to operations to address specific forecast challenges, including the Cooperative Institute for Research in the Atmosphere (CIRA) Layered Precipitable Water, the National Environmental Satellite, Data, and Information Service (NESDIS) Snowfall Rate product, NOAA Unique Combined Atmospheric Processing System (NUCAPS) Soundings, ozone products from the Atmospheric Infrared Sounder (AIRS), Cross-track Infrared Sounder/Advanced Technology Microwave Sounder (CrIS/ATMS), and Infrared Atmospheric Sounding Interferometer (IASI). In addition, new satellite domains have been created to provide forecasters at the NWS Ocean Prediction Center and Weather Prediction Center with better quality imagery at high latitudes. This has led to research projects that are addressing forecast challenges such as tropical to extratropical transition and explosive cyclogenesis. This presentation will provide examples of how the MPS PG has been introducing and integrating

  7. Integrated Satellite-HAP Systems

    Cianca, Ernestina; De Sanctis, Mauro; De Luise, Aldo


    for an efficient hybrid terrestrial-satellite communication system. Two integrated HAP-satellite scenarios are presented, in which the HAP is used to overcome some of the shortcomings of satellite- based communications. Moreover, it is shown that the integration of HAPs with satellite systems can be used......Thus far, high-altitude platform (HAP)-based systems have been mainly conceived as an alternative to satellites for complementing the terrestrial network. This article aims to show that HAP should no longer be seen as a competitor technology by investors of satellites, but as a key element...

  8. 微纳卫星专用发射运载器发展趋势研究%Research on the Trends of Developing Dedicated Launch Vehicle for Micro/Nano Satellite



    微纳卫星低成本、快速专用发射运载器是近些年来航天运输领域人们研究关注的问题之一。本文在简要介绍国外微纳卫星发展现状及趋势的基础上,分析微纳卫星发射运载器市场及供求关系,研究专用发射运载器研发及概念技术发展趋势,探讨专用发射运载器在民用和军事领域的发展前景。%The low-cost/responsive dedicated launch vehicle for micro/nano satellite is one of the problem in the area of aerospace transportation. This paper introduces development states and trends of micro/nano satelite , analyzes the supply and demand of the dedicated launch vehicle market, researches the development, concept and technology of the dedicated launch vehicle, discusses the trends of the dedicated launch vehicle in civil and military area.

  9. Progress in satellite quantum key distribution

    Bedington, Robert; Arrazola, Juan Miguel; Ling, Alexander


    Quantum key distribution (QKD) is a family of protocols for growing a private encryption key between two parties. Despite much progress, all ground-based QKD approaches have a distance limit due to atmospheric losses or in-fibre attenuation. These limitations make purely ground-based systems impractical for a global distribution network. However, the range of communication may be extended by employing satellites equipped with high-quality optical links. This manuscript summarizes research and development which is beginning to enable QKD with satellites. It includes a discussion of protocols, infrastructure, and the technical challenges involved with implementing such systems, as well as a top level summary of on-going satellite QKD initiatives around the world.

  10. Satellite Ocean Biology: Past, Present, Future

    McClain, Charles R.


    Since 1978 when the first satellite ocean color proof-of-concept sensor, the Nimbus-7 Coastal Zone Color Scanner, was launched, much progress has been made in refining the basic measurement concept and expanding the research applications of global satellite time series of biological and optical properties such as chlorophyll-a concentrations. The seminar will review the fundamentals of satellite ocean color measurements (sensor design considerations, on-orbit calibration, atmospheric corrections, and bio-optical algorithms), scientific results from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Moderate resolution Imaging Spectroradiometer (MODIS) missions, and the goals of future NASA missions such as PACE, the Aerosol, Cloud, Ecology (ACE), and Geostationary Coastal and Air Pollution Events (GeoCAPE) missions.

  11. Space Solar Power Satellite Systems, Modern Small Satellites, and Space Rectenna

    Bergsrud, Corey Alexis Marvin

    Space solar power satellite (SSPS) systems is the concept of placing large satellite into geostationary Earth orbit (GEO) to harvest and convert massive amounts of solar energy into microwave energy, and to transmit the microwaves to a rectifying antenna (rectenna) array on Earth. The rectenna array captures and converts the microwave power into usable power that is injected into the terrestrial electric grid for use. This work approached the microwave power beam as an additional source of power (with solar) for lower orbiting satellites. Assuming the concept of retrodirectivity, a GEO-SSPS antenna array system tracks and delivers microwave power to lower orbiting satellites. The lower orbiting satellites are equipped with a stacked photovoltaic (PV)/rectenna array hybrid power generation unit (HPGU) in order to harvest solar and/or microwave energy for on-board use during orbit. The area, and mass of the PV array part of the HPGU was reduced at about 32% beginning-of-life power in order to achieve the spacecraft power requirements. The HPGU proved to offer a mass decrease in the PGU, and an increase in mission life due to longer living component life of the rectenna array. Moreover, greater mission flexibility is achieved through a track and power delivery concept. To validate the potential advantages offered by a HPGU, a mission concept was presented that utilizes modern small satellites as technology demonstrators. During launch, a smaller power receiving "daughter" satellite sits inside a larger power transmitting "mother" satellite. Once separated from the launch vehicle the daughter satellite is ejected away from the mother satellite, and each satellite deploys its respective power transmitting or power receiving hardware's for experimentation. The concept of close proximity mission operations between the satellites is considered. To validate the technology of the space rectenna array part of the HPGU, six milestones were completed in the design. The first

  12. Satellite Formation based on SDDF Method

    Yu Wang


    Full Text Available The technology of satellite formation flying has being a research focus in flight application. The relative position and velocity between satellites are basic parameters to achieve the control of formation flight during the satellite formation flying mission. In order to improve the navigation accuracy, a new filter different from Extended Kalman Filter (EKF should be adopted to estimate the errors of relative position and velocity, which is based on the nonlinearity of the kinetic model for the satellite formation flying. A nonlinear Divided Difference Filter (DDF based on Stirling interpolation formula was proposed in this paper. According to the linearity of the measurement equation for the filter, a simplified differential filter was designed by means of expanding the polynomial of the nonlinear system equation and linear approximating of the finite differential interpolation. Digital simulation experiment for the relative positioning of satellite formation flying was carried out. The result demonstrates that the filter proposed in this paper has a higher filtering accuracy, faster convergence speed and better stability. Compared with the EKF, the estimation accuracy of the relative position and velocity has improved by 77.1%and 47% respectively in the method of simplified DDF, which indicates the significance for practical applications. 

  13. Advantages of Hybrid Global Navigation Satellite Systems

    Asim Bilajbegović


    Full Text Available In a decision-making situation, what kind of GPS equipment to purchase, one always has a dilemma, tobuy hybrid (GPS+GLONASS or only GPS receivers? In the case of completeness of the GLONASS satellite system, this dilemma probably would not have existed. The answer to this dilemma is given in the present paper, but for the constellation of the GLONASS satellites in summer 2006 (14 satellites operational. Due to the short operational period of these satellites (for example GLONASS-M, 5 years, and not launching new ones, at this moment (February 25, 2007, only 10 satellites are operational. For the sake of research and giving answers to these questions, about 252 RTK measurements have been done using (GPS and GNSS receivers, on points with different obstructions of horizon. Besides that, initialisation time has been investigated for both systems from about 480 measurements, using rover's antenna with metal cover, during a time interval of 0.5, 2 and 5 seconds. Moreover, accuracy, firmware declared accuracy and redundancy of GPS and GNSS RTK measurements have been investigating.  

  14. Educational Applications of Communications Satellites in Canada. New Technologies in Canadian Education Series. Paper 12.

    Richmond, J. Murray

    Canada has explored the use of satellites as a means to provide information and communications services to geographically isolated populations since 1962. Between 1972 and 1984, five series of satellites known as Anik A, B, C, and D and Hermes were launched. Each satellite provided expanded communications services, and each led to research and…

  15. Man-made Satellites



    If you watch the sky about an hour after the sun goes down, you may see some “moving stars”. But they're not real stars. They're manmade satellites (卫星). And the biggest of all is the International Space Station (ISS国际空间站).

  16. Observations of artificial satellites



    Full Text Available The following publication gives the results of photographic
    observations of artificial satellites made at Asiago during the second
    and third year of this programme. The fixed camera technique and that
    with moving film (the latter still in its experimental stage have been used.

  17. Experimental Satellite Quantum Communications.

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


    Quantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER=4.6% for a total link duration of 85 s. The mean photon number per pulse μ_{sat} leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers.

  18. Perception via satellite

    Robinove, Charles J.


    The earth resources observation satellite (EROS) program in the Department of the Interior is intended to gather and use data from satellites and aircraft on natural and man-made features of the earth's surface. Earth resources technology satellite will provide the EROS program with data for use in dealing with natural resource problems and understanding the interaction between man and the environment. Applications will include studies of tectonic features, hydrologic problems, location of fish schools, determination of the conditions of range land, mapping land use for urban planning, studies of erosion and change along coastlines and major streams, and inventories of land use and land forms. In addition, the ERTS data may be used for detecting forest and crop diseases and inventorying crops. The ERTS satellite will be in a polar, sun-synchronous orbit so that each point on the earth's surface will be sensed every 17 to 20 days, at the same time of day. Multispectral photography is being investigated for its usefulness in hydrology. Side-looking airborne radar has not yet been widely used in hydrologic studies, although it is an excellent tool for all-weather, day or night, coverage of large areas. Other techniques being investigated include passive microwave radiometry, ultraviolet and visible stimulated luminescence, and absorption spectroscopy.

  19. Satellite Photometric Error Determination


    of nearly specular reflections from most solar panels. Our primary purpose in presenting these two plots is to demonstrate the usefulness of...than a transformation for stars because the spectral energy distribution of satellites can change with phase angle and is subject to specular

  20. Creating Better Satellite Conferences.

    Horner, Tommy


    Presents four ways to improve broadcasts of company satellite conferences, including creative site selection (using facilities at educational institutions rather than hotel rooms); creative programming (using graphics and other interruptions to break up lectures or speeches); creative crew selection; and creative downlink site activities (to…

  1. Ocean surveillance satellites

    Laurent, D.

    Soviet and U.S. programs involving satellites for surveillance of ships and submarines are discussed, considering differences in approaches. The Soviet program began with the Cosmos 198 in 1967 and the latest, the Cosmos 1400 series, 15 m long and weighing 5 tons, carry radar for monitoring ships and a nuclear reactor for a power supply. Other Soviet spacecraft carrying passive microwave sensors and ion drives powered by solar panels have recently been detonated in orbit for unknown reasons. It has also been observed that the Soviet satellites are controlled in pairs, with sequential orbital changes for one following the other, and both satellites then overflying the same points. In contrast, U.S. surveillance satellites have been placed in higher orbits, thus placing greater demands on the capabilities of the on-board radar and camera systems. Project White Cloud and the Clipper Bow program are described, noting the continued operation of the White Cloud spacecraft, which are equipped to intercept radio signals from surface ships. Currently, the integrated tactical surveillance system program has completed its study and a decision is expected soon.

  2. OMV With Satellite


    This 1986 artist's concept shows the Orbital Maneuvering Vehicle (OMV) towing a satellite. As envisioned by Marshall Space Flight Center plarners, the OMV would be a remotely-controlled free-flying space tug which would place, rendezvous, dock, and retrieve orbital payloads.

  3. Advances in satellite oceanography

    Brown, O. B.; Cheney, R. E.


    Technical advances and recent applications of active and passive satellite remote sensing techniques to the study of oceanic processes are summarized. The general themes include infrared and visible radiometry, active and passive microwave sensors, and buoy location systems. The surface parameters of sea surface temperature, windstream, sea state, altimetry, color, and ice are treated as applicable under each of the general methods.

  4. MLS observations of stratospheric waves in temperature and O[sub 3] during the 1992 southern winter

    Fishbein, E.F.; Elson, L.S.; Froidevaux, L.; Manney, G.L.; Read, W.G.; Waters, J.W.; Zurek, R.W. (California Institute of Technology, Pasadena (United States))


    This paper reports on wave activity observed in stratospheric temperature and ozone density by the microwave limb sounder (MLS) on board the upper atmosphere research satellite (UARS), during the 1992 southern winter. The satellite observes both stationary and travelling waves, and finds a correlation between the wave activity of the temperature and ozone. This indicates that transport of ozone is being accomplished by the wave activity.

  5. Cibola flight experiment satellite

    Davies, P.; Liddle, Doug; Paffett, John; Sweeting, Martin; Curiel, A.; Sun, Wei; Eves, Stuart


    In order to achieve an "economy of scale" with respect to payload capacity the major trend in telecommunications satellites is for larger and larger platforms. With these large platforms the level of integration between platform and payload is increasing leading to longer delivery schedules. The typical lifecycle for procurement of these large telecommunications satellites is now 3-6 years depending on the level of non-recurring engineering needed. Surrey Satellite Technology Ltd (SSTL) has designed a low-cost platform aimed at telecommunications and navigation applications. SSTL's Geostationary Minisatellite Platform (GMP) is a new entrant addressing the lower end of the market with payloads up to 250kg requiring less than 1.5 kW power. The British National Space Centre through the MOSAIC Small Satellite Initiative supported the development of GMP. The main design goals for GMP are low-cost for the complete mission including launch and operations and a platform allowing flexible payload accommodation. GMP is specifically designed to allow rapid development and deployment with schedules typically between 1 and 2 years from contract signature to flight readiness. GMP achieves these aims by a modular design where the level of integration between the platform and payload is low. The modular design decomposes the satellite into three major components - the propulsion bay, the avionics bay and the payload module. Both the propulsion and avionics bays are reusable, largely unchanged, and independent of the payload configuration. Such a design means that SSTL or a 3rd party manufacturer can manufacture the payload in parallel to the platform with integration taking place quite late in the schedule. In July 2003 SSTL signed a contract for ESA's first Galileo navigation satellite known as GSTBV2/A. The satellite is based on GMP and ESA plan to launch it into a MEO orbit late in 2005. The second flight of GMP is likely to be in 2006 carrying a geostationary payload

  6. Videoconferencing via satellite: Opening Congress to the people: Summary report

    Wood, F. B.; Coates, V. T.; Chartrand, R. L.; Ericson, R. F.


    Action research is presented to evaluate, through actual demonstrations, whether satellite videoconferencing can provide a new mechanism for informed dialog between congressmen and constituents and as a result strengthen the legislative process.

  7. Defense Meteorological Satellite Program (DMSP)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Defense Meteorological Satellite Program (DMSP) satellites collect visible and infrared cloud imagery as well as monitoring the atmospheric, oceanographic,...

  8. Satellite Meteorology Education Resources Freely Available from COMET°

    Abshire, W. E.; Dills, P. N.


    The COMET° Program ( receives funding from NOAA NESDIS, EUMETSAT, and the Meteorological Service of Canada to support education and training efforts in satellite meteorology. These partnerships enable COMET to create educational materials of global interest on the application of products from geostationary and polar-orbiting remote sensing platforms. Recently, COMET's satellite education programs have focused on both current and next generation satellites and their relevance to operational forecasters and other communities. By partnering with experts from the Naval Research Laboratory, NOAA-NESDIS and its Cooperative Institutes, MSC, and other user communities, COMET stimulates greater utilization of satellite data and products. COMET also continues to broaden the scope of its training to include materials on the EUMETSAT Polar-orbiting System (EPS) and Meteosat geostationary satellites. EPS represents an important contribution to the Initial Joint Polar System between NOAA and EUMETSAT, while Meteosat Second Generation imaging capabilities provide an authentic proving ground for the next-generation GOES-R imager. This presentation provides an overview of COMET's recent satellite education efforts including courses and publications that focus on topics like multispectral RGB products, detecting atmospheric dust, and climate monitoring from satellites. Over 50 satellite-focused self-paced online materials are freely available via the Satellite Topic area of the MetEd Web site ( and COMET's Environmental Satellite Resource Center (ESRC)( The ESRC, another important resource developed for use by the geosciences and education communities, is a searchable, database driven Web site that provides easy access to a wide range of useful information and training materials on Earth-observing satellites. Simple free online registration is required to access all training materials and the

  9. Concept design of HAYATE : Small satellite for supporting Antarctic geophysical observation

    Yoshihara, Keisuke; Sugiura, Yoshiki; Sekiguchi,Masato; Ui, Kyoichi; Tsurumi,Singo; Nakaya, Koji; Mori, Makoto; Matsunaga, Saburo; Ohkami, Yoshiaki


    This paper presents the results of conceptual design of a small communication satellite (HAYATE) for supporting research in Antarctica and remote islands. The HAY ATE satellite collects environmental data from unmanned probes located on the Antarctic ice plate and also transmits data from Syowa Station in Antarctica to Japan and the United States. Through the satellite mission analyses, we confirmed that the HAYATE satellite would be able to gather data for GPS baseline analysis and to observ...

  10. Model of load distribution for earth observation satellite

    Tu, Shumin; Du, Min; Li, Wei


    For the system of multiple types of EOS (Earth Observing Satellites), it is a vital issue to assure that each type of payloads carried by the group of EOS can be used efficiently and reasonably for in astronautics fields. Currently, most of researches on configuration of satellite and payloads focus on the scheduling for launched satellites. However, the assignments of payloads for un-launched satellites are bit researched, which are the same crucial as the scheduling of tasks. Moreover, the current models of satellite resources scheduling lack of more general characteristics. Referring the idea about roles-based access control (RBAC) of information system, this paper brings forward a model based on role-mining of RBAC to improve the generality and foresight of the method of assignments of satellite-payload. By this way, the assignment of satellite-payload can be mapped onto the problem of role-mining. A novel method will be introduced, based on the idea of biclique-combination in graph theory and evolutionary algorithm in intelligence computing, to address the role-mining problem of satellite-payload assignments. The simulation experiments are performed to verify the novel method. Finally, the work of this paper is concluded.

  11. Telelibrary: Library Services via Satellite.

    Liu, Rosa


    Investigates the provision of library services via satellite, explains briefly the operation and advantages of communication satellites, and discusses the various telecommunications equipment and services which, when coupled with satellite transmission, will enhance library activities. Demand trend projections for telecommunications services…

  12. Mobile satellite service for Canada

    Sward, David


    The Mobile Satellite (MSAT) system and a special program designed to provide interim mobile satellite services (IMSS) during the construction phase of MSAT are described. A mobile satellite system is a key element in extending voice and and data telecommunications to all Canadians.

  13. Satellite Contributions to Global Change Studies

    Parkinson, Claire L.


    By providing a global view with a level playing field (no region missed because of unfavorable surface conditions or political boundaries), satellites have made major contributions to improved monitoring and understanding of our constantly changing planet. The global view has allowed surprising realizations like the relative sparsity of lightning strikes over oceans and the large-scale undulations on the massive Antarctic ice sheet. It has allowed the tracking of all sorts of phenomena, including aerosols, both natural and anthropogenic, as they move with the atmospheric circulation and impact weather and human health. But probably nothing that the global view allows is more important in the long term than its provision. of unbiased data sets to address the issue of global change, considered by many to be among the most important issues facing humankind today. With satellites we can monitor atmospheric temperatures at all latitudes and longitudes, and obtain a global average that lessens the likelihood of becoming endlessly mired in the confusions brought about by the certainty of regional differences. With satellites we can monitor greenhouse gases such as CO2 not just above individual research stations but around the globe. With satellites we can monitor the polar sea ice covers, as we have done since the late 1970s, determining and quantifying the significant reduction in Arctic sea ice and the slight growth in Antarctic sea ice over that period, With satellites we can map the full extent and changes in the Antarctic stratospheric ozone depletions that were first identified from using a single ground station; and through satellite data we have witnessed from afar land surface changes brought about by humans both intentionally, as with wide-scale deforestation, and unintentionally, as with the decay of the Aral Sea. The satellite data are far from sufficient for all that we need in order to understand the global system and forecast its changes, as we also need

  14. Satellite Aerodynamics and Density Determination from Satellite Dynamic Response

    Karr, G. R.


    The aerodynamic drag and lift properties of a satellite are first expressed as a function of two parameters associated with gas-surface interaction at the satellite surface. The dynamic response of the satellite as it passes through the atmosphere is then expressed as a function of the two gas-surface interaction parameters, the atmospheric density, the satellite velocity, and the satellite orientation to the high speed flow. By proper correlation of the observed dynamic response with the changing angle of attack of the satellite, it is found that the two unknown gas-surface interaction parameters can be determined. Once the gas-surface interaction parameters are known, the aerodynamic properties of the satellite at all angles of attack are also determined.

  15. Research

    A possible strategy to influence students' understanding and perception ... researcher in higher education teaching and learning facilitated the data- ..... B. Qualitative content analysis in nursing research: Concepts, procedures and measures.

  16. Research in Adaptive Beamforming for Satellite Communications.


    are obtained with the right hand side being -2 kA/N-1/2[l). The solution to these equations is given by (27) with E-11 A (1- acoso + c) (1 - acos# + c...9) b12( + b2 2(#) + 2cbI(j) + c2 where bl(#) - I- acoso (E.1O) b2( - asin# (:.1l) Thus ar2 () + ai2() " (b1 2(.) - b2 2 (.))2 + c2(b 12() + b2 2

  17. Data Collection Satellite Application in Precision Agriculture

    Durào, O.


    Agricultural Instrumentation Research Center, Brazilian Agricultural Research Corporation; Space Programs Brazil launched in 1993 its first satellite partially built and entirely designed, integrated, tested and operated in the country. It was the SCD-1 satellite, a small (115 kg. and an octagonal prism with 80 cm. height and an external diameter of 100 cm.) with a payload transponder that receives data from ground platforms spread all over the country (including its sea shore). These data are then retransmitted to a receiving station at every satellite pass. Data collected and received are processed at Data Collection Mission Center for distribution via internet at most 30 min after the satellite pass. The ground platforms are called PCD's and differ in the parameters measured according to its purpose and location. Thus, they are able to measure temperature, rain level, wind direction, solar radiation, carbon monoxide as well as many others, beyond its own location. SCD- 1 had a nominal designed life of one year, but is still functioning. It is a LEO satellite with inclination of 25°. In 1998, the country launched SCD-2, with the same purpose, but in phase with SCD-1 . Other differences were a higher index of Brazilian made components and an active attitude control subsystem for the spin rate provided by the magnetic torque coils (these in accordance with a development strategy previously planned). In 1999 the country launched in cooperation with China a remote sensing satellite (mass of 1.4 ton.) called CBERS-1. This satellite is sun synchronous (98° inclination) and also carries a transponder for data collection/transmission as a secondary payload. Thus, the country has now three satellites with data collection/transmission capabilities, two in low inclination phased orbits and one in polar orbit, providing a nice coverage both geographical and temporal not only to its territory but also to other regions of the world.. At first there were not too many PCD

  18. Thematic mapping from satellite imagery

    Denègre, J


    Thematic Mapping from Satellite Imagery: A Guidebook discusses methods in producing maps using satellite images. The book is comprised of five chapters; each chapter covers one stage of the process. Chapter 1 tackles the satellite remote sensing imaging and its cartographic significance. Chapter 2 discusses the production processes for extracting information from satellite data. The next chapter covers the methods for combining satellite-derived information with that obtained from conventional sources. Chapter 4 deals with design and semiology for cartographic representation, and Chapter 5 pre

  19. Satellite material contaminant optical properties

    Wood, B. E.; Bertrand, W. T.; Seiber, B. L.; Kiech, E. L.; Falco, P. M.; Holt, J. D.


    The Air Force Wright Research and Development Center and the Arnold Engineering Development Center are continuing a program for measuring optical effects of satellite material outgassing products on cryo-optic surfaces. Presented here are infrared (4000 to 700 cm(-1)) transmittance data for contaminant films condensed on a 77 K germanium window. From the transmittance data, the contaminant film refractive and absorptive indices (n, k) were derived using an analytical thin-film interference model with a nonlinear least-squares algorithm. To date 19 materials have been studied with the optical contents determined for 13 of those. The materials include adhesives, paints, composites, films, and lubricants. This program is continuing and properties for other materials will be available in the future.

  20. Satellite Control Laboratory

    Wisniewski, Rafal; Bak, Thomas


    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three...... of the laboratory is to conduct dynamic tests of the control and attitude determination algorithms during nominal operation and in abnormal conditions. Further it is intended to use SatLab for validation of various algorithms for fault detection, accommodation and supervisory control. Different mission objectives...

  1. Declassified Intelligence Satellite Photographs



    Declassified photographs from U.S. intelligence satellites provide an important worldwide addition to the public record of the Earth's land surface. This imagery was released to the National Archives and Records Administration (NARA) and the U.S. Geological Survey (USGS) in accordance with Executive Order 12951 on February 23, 1995. The NARA has the original declassified film and a viewing copy. The USGS has another copy of the film to complement the Landsat archive. The declassified collection involves more than 990,000 photographs taken from 1959 through 1980 and was released on two separate occasions: February 1995 (Declass 1) and September 2002 (Declass 2). The USGS copy is maintained by the Earth Resources Observation and Science (EROS) Center, near Sioux Falls, South Dakota. Both the NARA and EROS provide public access to this unique collection that extends the record of land-surface change back another decade from the advent of the Landsat program that began satellite operations in 1972.

  2. Satellites in Canadian broadcasting

    Siocos, C. A.

    The involvement of Canadian broadcasting and related enterprises in satellite telecommunications is surveyed. This includes point-to-point transmissions and direct ones to the general public. The mode of such utilizations is indicated in both these cases. For the forthcoming DBS systems the many types of service offerings and utilization concepts under discussion elasewhere are presented as well as the business prospects and regulatory climate offering them.

  3. Neptune: Minor Satellites

    Murdin, P.


    All but one of Neptune's minor satellites orbit within or just outside its ringsystem; the exception is the distant object Nereid. Some of them are betterdescribed as `mid-sized' rather than `minor', but are included under thisheading as little is known of them. The inner four, with approximatediameters, are Naiad (60 km), Thalassa (80 km), Despina (150 km) and Galatea(160 km). The first three lie...

  4. Satellite Surveillance: Domestic Issues


    earthquake and tsunami in the Indian Ocean and Hurricane Katrina in 2005, when the NGA provided graphics for “relief efforts that depicted the locations of...that show the damage resulting from an earthquake , fire, flood, hurricane, oil spill, or volcanic eruption.8 Bush Administration Policies...Satellite information has continued to have important civil applications in such disparate areas as the movement of glaciers in Yakutat Bay in Alaska

  5. Communications satellites - The experimental years

    Edelson, B. I.


    Only eight years after the launc of Sputnik-1 by the Soviet Union, the first commercial satellite, 'Early Bird', entered service. In just twelve years commercial satellite service extended around the earth and became profitable. The reasons for the successful development of the communications satellite services in a comparatively short time are considered. These reasons are related to the presence of three ingredients, taking into account technology to create the system, communications requirements to form a market, and a management structure to implement the system. The formation of the concept of using earth orbiting satellites for telecommunications is discussed. It is pointed out that the years from 1958 to 1964 were the true 'experimental years' for satellite communications. The rapid development of technology during this crucial period is described, giving attention to passive satellites, active systems, and development satellites.

  6. Tethered satellite design

    Manarini, G.


    The capability of the satellite to perform a variety of space operations to be accomplished from the shuttle is reviewed considering use of the satellite with man-in-loop and closed loop modes and deployment (toward or away from Earth, up to 100 km), stationkeeping, retrieval and control of the satellite. Scientific payloads are to be used to perform experiments and scientific investigation for applications such as magnetometry, electrodynamics, atmospheric science, chemical release, communications, plasmaphysics, dynamic environment, and power and thrust generation. The TSS-S will be reused for at least 3 missions after reconfiguration and refurbishment by changing the peculiar mission items such as thermal control, fixed boom for experiments, aerodynamic tail for yaw attitude control, external skin, experiments, and any other feature. The TSS-S is to be composed of three modules in order to allow independent integration of a single module and to facilitate the refurbishment and reconfiguration between flights. The three modules are service, auxiliary propulsion, and payload modules.

  7. Heart Monitoring By Satellite


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

  8. A satellite anemometer

    Hanson, W. B.; Heelis, R. A.


    This report describes the design, development, and testing of components of a satellite anemometer, an instrument for measuring neutral winds in the upper atmosphere from a satellite platform. The device, which uses four nearly identical pressure sensors, measures the angle of arrival of the bulk neutral flow in the satellite frame of reference. It could also be used in a feedback loop to control spacecraft attitude with respect to the ram velocity direction. We have now developed miniaturized ionization pressure gauges that will work well from the slip flow region near 115 km up to the base of the exosphere, which covers the entire altitude range currently being considered for Tether. Laboratory tests have demonstrated a very linear response to changes in ram angle out to +/- 20 deg. (transverse wind component of 2.7 km s(exp -1)) from the ram, and a monotonic response to out beyond 45 deg. Pitch (vertical wind) and yaw (horizontal wind) can be sampled simultaneously and meaningfully up to 10 Hz. Angular sensitivity of 30 arc seconds (approximately 1 ms(exp -1) is readily attainable, but absolute accuracy for winds will be approximately 1 deg (130 m/s) unless independent attitude knowledge is available. The critical elements of the design have all been tested in the laboratory.

  9. Binary Satellite Galaxies

    Evslin, Jarah


    Suggestions have appeared in the literature that the following five pairs of Milky Way and Andromeda satellite galaxies are gravitationally bound: Draco and Ursa Minor, Leo IV and V, Andromeda I and III, NGC 147 and 185, and the Magellanic clouds. Under the assumption that a given pair is gravitationally bound, the Virial theorem provides an estimate of its total mass and so its instantaneous tidal radius. For all of these pairs except for the Magellanic clouds the resulting total mass is 2 to 4 orders of magnitude higher than that within the half light radius. Furthermore in the case of each pair except for Leo IV and Leo V, the estimated tidal radius is inferior to the separation between the two satellites. Therefore all or almost all of these systems are not gravitationally bound. We note several possible explanations for the proximities and similar radial velocities of the satellites in each pair, for example they may have condensed from the same infalling structure or they may be bound by a nongravitatio...

  10. Arctic Ozone Depletion from UARS MLS Measurements

    Manney, G. L.


    Microwave Limb Sounder (MLS) measurements of ozone during four Arctic winters are compared. The evolution of ozone in the lower stratosphere is related to temperature, chlorine monoxide (also measured by MLS), and the evolution of the polar vortex. Lagrangian transport calculations using winds from the United Kingdom Meteorological Office's Stratosphere-Troposphere Data Assimilation system are used to estimate to what extent the evolution of lower stratospheric ozone is controlled by dynamics. Observations, along with calculations of the expected dynamical behavior, show evidence for chemical ozone depletion throughout most of the Arctic lower stratospheric vortex during the 1992-93 middle and late winter, and during all of the 1994-95 winter that was observed by MLS. Both of these winters were unusually cold and had unusually cold and had unusually strong Arctic polar vortices compared to meteorological data over the past 17 years.

  11. Landsat卫星图像用于大面积森林扰动监测的研究进展%Progress of researches on monitoring large-area forest disturbance by Landsat satellite images

    祝善友; 张莹; 张海龙; 曹云; 张桂欣


    The frequent forest disturbance caused by natural factors and human activities has very important effects on forest resources management, climate change and some other fields. Under the background of global warming, researches on forest disturbance monitoring and its corresponding influence have become one of the hot topics both in China and abroad. Based on a detailed analysis of the previous studies, this paper has reviewed the progress of monitoring methods for the large-area forest disturbance by using Landsat satellite imagery, which mainly include wall- to - wall mapping, sampling mapping and data fusion with the image of low spatial resolution. The advantages and disadvantages of these methods as well as the possible research prospects in the future are also dis-cussed.%自然因素和人为原因使不同程度的森林扰动现象频繁发生,对森林资源管理、气候变化等产生了重要影响。在全球变暖的大背景下,大面积森林扰动监测及其影响已成为目前国内外研究的热点与前沿问题之一,Landsat系列卫星是最为常用的一类数据。在深入分析国内外相关方法的基础上,综述了Landsat卫星图像用于大面积森林扰动遥感监测的研究进展,主要方法包括全地面覆盖制图、抽样方法和与较低空间分辨率图像复合方法3大类,并对比分析了这些方法的优缺点,最后对未来可能的研究方向做出了展望。

  12. Satellite-based terrestrial production efficiency modeling

    Obersteiner Michael


    Full Text Available Abstract Production efficiency models (PEMs are based on the theory of light use efficiency (LUE which states that a relatively constant relationship exists between photosynthetic carbon uptake and radiation receipt at the canopy level. Challenges remain however in the application of the PEM methodology to global net primary productivity (NPP monitoring. The objectives of this review are as follows: 1 to describe the general functioning of six PEMs (CASA; GLO-PEM; TURC; C-Fix; MOD17; and BEAMS identified in the literature; 2 to review each model to determine potential improvements to the general PEM methodology; 3 to review the related literature on satellite-based gross primary productivity (GPP and NPP modeling for additional possibilities for improvement; and 4 based on this review, propose items for coordinated research. This review noted a number of possibilities for improvement to the general PEM architecture - ranging from LUE to meteorological and satellite-based inputs. Current PEMs tend to treat the globe similarly in terms of physiological and meteorological factors, often ignoring unique regional aspects. Each of the existing PEMs has developed unique methods to estimate NPP and the combination of the most successful of these could lead to improvements. It may be beneficial to develop regional PEMs that can be combined under a global framework. The results of this review suggest the creation of a hybrid PEM could bring about a significant enhancement to the PEM methodology and thus terrestrial carbon flux modeling. Key items topping the PEM research agenda identified in this review include the following: LUE should not be assumed constant, but should vary by plant functional type (PFT or photosynthetic pathway; evidence is mounting that PEMs should consider incorporating diffuse radiation; continue to pursue relationships between satellite-derived variables and LUE, GPP and autotrophic respiration (Ra; there is an urgent need for

  13. The Italian contribution to the CSES satellite

    Conti, Livio


    We present the Italian contribution to the CSES (China Seismo-Electromagnetic Satellite) mission. The CSES satellite aims at investigating electromagnetic field, plasma and particles in the near-Earth environment in order to study in particular seismic precursors, particles fluxes (from Van Allen belts, cosmic rays, solar wind, etc.), anthropogenic electromagnetic pollution and more in general the atmosphere-ionosphere-magnetosphere coupling mechanisms that can affect the climate changes. The launch of CSES - the first of a series of several satellite missions - is scheduled by the end of 2016. The CSES satellite has been financed by the CNSA (China National Space Agency) and developed by CEA (China Earthquake Administration) together with several Chinese research institutes and private companies such as the DFH (that has developed the CAST2000 satellite platform). Italy participates to the CSES satellite mission with the LIMADOU project funded by ASI (Italian Space Agency) in collaboration with the Universities of Roma Tor Vergata, Uninettuno, Trento, Bologna and Perugia, as well as the INFN (Italian National Institute of Nuclear Physics), INGV (Italian National Institute of Geophysics and Volcanology) and INAF-IAPS (Italian National Institute of Astrophysics and Planetology). Many analyses have shown that satellite observations of electromagnetic fields, plasma parameters and particle fluxes in low Earth orbit may be useful in order to study the existence of electromagnetic emissions associated with the occurrence of earthquakes of medium and high magnitude. Although the earthquakes forecasting is not possible today, it is certainly a major challenge - and perhaps even a duty - for science in the near future. The claims that the reported anomalies (of electromagnetic, plasma and particle parameters) are seismic precursors are still intensely debated and analyses for confirming claimed correlations are still lacking. In fact, ionospheric currents, plasma

  14. 卫星合成孔径雷达探测海底地形研究进展%Progress in Research of Satellite SAR Detection of Ocean Bottom Topography

    郑全安; 谢玲玲


    Using satellite synthetic aperture radar (SAR)to detect ocean bottom topography is a challeng-ing problem for the research of ocean remote sensing physics and ocean dynamics.The reason is that radar pulses are unable to penetrate into seawater based on the principles of electromagnetic wave propagation, thus unable to detect ocean bottom topographic features directly.However,ocean bottom topographic fea-tures indeed show up on satellite SAR images in many cases.These topographic features are distributed not only in the shallow waters with depths shallower than 100 m,but also in the deep waters with depths deeper than 600~800 m and even 2000~3000 m.This paper overviews the frontier and progress in studies of this field.The key points include the fundamental theories for radar imaging of ocean surface processes, the SAR imaging theories for ocean bottom topographic features in three ocean areas:the Liaodong Shoal and the Taiwan Tan of China as well as the Gulf Stream region east of USA.The three cases represent lon-gitudinal shear flow passing over parallel ocean bottom topography,stratified traverse flow crossing over parallel (periodic)ocean bottom topography and strong ocean current passing over isolated ocean bottom topography.The theories and analysis methods derived from the three cases may serve as a baseline for in-terpretations of more complex cases and explorations of new application fields.%利用卫星合成孔径雷达(SAR)图像信息探测海底地形是海洋遥感物理学和海洋动力学研究具有挑战性的问题,这是因为根据电磁波传播原理,雷达脉冲没有能力穿透海水,因而不可能直接探测到海底地形特征,可是,许多卫星 SAR 图像上确实显示出海底地形特征。这些海底地形不仅分布在水深小于100 m 的浅海,而且在600~800 m 甚至2000~3000 m 的深海区也有发现。本文概略介绍该领域的发展前沿和研究进展,主要内容包括海面过程雷达成像基

  15. Digital audio and video broadcasting by satellite

    Yoshino, Takehiko

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

  16. Satellite Upper Air Network (SUAN)

    Reale, Tony L.; Thorne, Peter


    During the past 20 years of NOAA operational polar satellites, it has become evident that a growing problem concerning their utilization in Climate and also Numerical Weather Prediction (NWP) applications are the systematic errors and uncertainties inherent in the satellite measurements. Similar arguments can be made for global radiosonde observations. These uncertainties are often larger than the sensitive signals and processes, that satellite and radiosonde measurements are designed to reveal, particularly in the realm of climate. Possible strategies to quantify and compensate for these problems include the analysis of satellite overlap data and/or available collocations of satellite and ground truth (radiosonde) observations. However, overlap observations are typically not available except in extreme polar regions and current sampling strategies for compiling collocated radiosonde and satellite observations are insufficient, further compounding the inherent uncertainties in the ground-truth radiosonde data. A Satellite Upper Air Network is proposed to provide reference radiosonde launches coincident with operational polar satellite(s) overpass. The SUAN consist of 36 global radiosonde stations sub-sampled from the Global Upper Air Network (GUAN), and is designed to provide a robust, global sample of collocated radiosonde and satellite observations conducive to the monitoring and validation of satellite and radiosonde observations. The routine operation of such a network in conjunction with operational polar satellites would provide a long-term of performance for critical observations of particular importance for climate. The following report presents a candidate network of 36 upper-air sites that could comprise a SUAN. Their selection along with the mutual benefit across the satellite, radiosonde, climate, numerical weather prediction (NWP) and radiative transfer (RT) model areas are discussed.

  17. Research

    A sequential mixed-methods research design was chosen. This research ... development of the questionnaire used in the second phase of the survey. Quantitative data ... Microsoft Office Excel 2010 spreadsheet, descriptive data analysis was applied .... undergraduate curriculum, and implementation and evaluation thereof,.

  18. Research



    Mar 2, 2015 ... Shared and mutually beneficial resources within international research ... organizations[1-9]. ... facilitate research career paths, but few career models exist in Africa ..... international and local resources to clinical studies locally. The ability of ... investigators were seen as an important asset for the transfer of.

  19. 1962 Satellite High Altitude Radiation Belt Database


    TR-14-18 1962 Satellite High Altitude Radiation Belt Database Approved for public release; distribution is unlimited. March...the Status of the High Altitude Nuclear Explosion (HANE) Trapped Radiation Belt Database”, AFRL-VS-PS-TR- 2006-1079, Air Force Research Laboratory...Roth, B., “Blue Ribbon Panel and Support Work Assessing the Status of the High Altitude Nuclear Explosion (HANE) Trapped Radiation Belt Database

  20. Local gravity disturbance estimation from multiple-high-single-low satellite-to-satellite tracking

    Jekeli, Christopher


    The idea of satellite-to-satellite tracking in the high-low mode has received renewed attention in light of the uncertain future of NASA's proposed low-low mission, Geopotential Research Mission (GRM). The principal disadvantage with a high-low system is the increased time interval required to obtain global coverage since the intersatellite visibility is often obscured by Earth. The U.S. Air Force has begun to investigate high-low satellite-to-satellite tracking between the Global Positioning System (GPS) of satellites (high component) and NASA's Space Transportation System (STS), the shuttle (low component). Because the GPS satellites form, or will form, a constellation enabling continuous three-dimensional tracking of a low-altitude orbiter, there will be no data gaps due to lack of intervisibility. Furthermore, all three components of the gravitation vector are estimable at altitude, a given grid of which gives a stronger estimate of gravity on Earth's surface than a similar grid of line-of-sight gravitation components. The proposed Air Force mission is STAGE (Shuttle-GPS Tracking for Anomalous Gravitation Estimation) and is designed for local gravity field determinations since the shuttle will likely not achieve polar orbits. The motivation for STAGE was the feasibility to obtain reasonable accuracies with absolutely minimal cost. Instead of simulating drag-free orbits, STAGE uses direct measurements of the nongravitational forces obtained by an inertial package onboard the shuttle. The sort of accuracies that would be achievable from STAGE vis-a-vis other satellite tracking missions such as GRM and European Space Agency's POPSAT-GRM are analyzed.

  1. Satellite remote-sensing technologies used in forest fire management

    TIAN Xiao-rui; Douglas J. Mcrae; SHU Li-fu; WANG Ming-yu; LI Hong


    Satellite remote sensing has become a primary data source for fire danger rating prediction, fuel and fire mapping, fire monitoring, and fire ecology research. This paper summarizes the research achievements in these research fields, and discusses the future trend in the use of satellite remote-sensing techniques in wildfire management. Fuel-type maps from remote-sensing data can now be produced at spatial and temporal scales quite adequate for operational fire management applications. US National Oceanic and Atmospheric Administration (NOAA) and Moderate Resolution Imaging Spectroradiometer (MODIS) satellites are being used for fire detection worldwide due to their high temporal resolution and ability to detect fires in remote regions. Results can be quickly presented on many Websites providing a valuable service readily available to fire agency. As cost-effective tools, satellite remote-sensing techniques play an important role in fire mapping. Improved remote-sensing techniques have the potential to date older fire scars and provide estimates of burn severity. Satellite remote sensing is well suited to assessing the extent of biomass burning, a prerequisite for estimating emissions at regional and global scales, which are needed for better understanding the effects of fire on climate change. The types of satellites used in fire research are also discussed in the paper. Suggestions on what remote-sensing efforts should be completed in China to modernize fire management technology in this country are given.

  2. Regional Bias of Satellite Precipitation Estimates

    Modrick, T. M.; Georgakakos, K. P.; Spencer, C. R.


    Satellite-based estimates of precipitation have improved the spatial availability of precipitation data particularly for regions with limited gauge networks due to limited accessibility or infrastructure. Understanding the quality and reliability of satellite precipitation estimates is important, especially when the estimates are utilitized for real-time hydrologic forecasting and for fast-responding phenomena. In partnership with the World Meteorological Organization (WMO), the U.S. Agency of International Development (USAID) and the National Ocean and Atmospheric Administration (NOAA), the Hydrologic Research Center has begun implementation of real-time flash flood warning systems for diverse regions around the world. As part of this effort, bias characteristics of satellite precipitation have been examined in these various regions, such includes portions of Southeastern Asia, Southeastern Europe, the Middle East, Central America, and the southern half of the African continent. The work has focused on the Global Hydro-Estimator (GHE) precipitation product from NOAA/NESDIS. These real-time systems utilize the GHE given low latency times of this product. This presentation focuses on the characterization of precipitation bias as compared to in-situ gauge records, and the regional variations or similarities. Additional analysis is currently underway considering regional bias for other satellite precipitation products (e.g., CMORPH) for comparison with the GHE results.

  3. Multichannel demultiplexer/demodulator technologies for future satellite communication systems

    Ivancic, William D.; Budinger, James M.; Staples, Edward J.; Abramovitz, Irwin; Courtois, Hector A.


    NASA-Lewis' Space Electronics Div. supports ongoing research in advanced satellite communication architectures, onboard processing, and technology development. Recent studies indicate that meshed VSAT (very small aperture terminal) satellite communication networks using FDMA (frequency division multiple access) uplinks and TDMA (time division multiplexed) downlinks are required to meet future communication needs. One of the critical advancements in such a satellite communication network is the multichannel demultiplexer/demodulator (MCDD). The progress is described which was made in MCDD development using either acousto-optical, optical, or digital technologies.

  4. Andean terraced hills (a use of satellite imagery)

    Sparavigna, Amelia Carolina


    The aim of this paper is in stimulating the use of satellite imagery, in particular the free service of Google Maps, to investigate the distribution of the agricultural technique of terraced hills in Andean countries, near Titicaca Lake. In fact, satellite maps can give a clear view of the overall surface modified by human work, being then a precious help for on-site archaeological researches and for historical analysis. Satellite imagery is also able to give the distribution of burial and worship places. The paper discusses some examples near the Titicaca Lake.

  5. Study on Service Level Management in Integrated Satellite Information Network

    SHANG Rui-qiang; ZHAO Jian-li; WANG Guang-xing


    Integrated Satellite Information Network (ISIN) includes those nodes in space and those on ground. It is the way to realize the fusion of satellite communication and traditional network technology. A satellite network management system based on Multiplex Network Management Protocol (MNMP) has accomplished traditional management, such as configuration, performance and fault management. An architecture of Service Level Management (SLM) in ISIN is proposed, and a service topology management and Service Level Agreement (SLA) are deeply researched. At last, service security and fault management are briefly discussed, and a simulation system is accomplished.

  6. Radio broadcasting via satellite

    Helm, Neil R.; Pritchard, Wilbur L.


    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.

  7. Understanding satellite navigation

    Acharya, Rajat


    This book explains the basic principles of satellite navigation technology with the bare minimum of mathematics and without complex equations. It helps you to conceptualize the underlying theory from first principles, building up your knowledge gradually using practical demonstrations and worked examples. A full range of MATLAB simulations is used to visualize concepts and solve problems, allowing you to see what happens to signals and systems with different configurations. Implementation and applications are discussed, along with some special topics such as Kalman Filter and Ionosphere. W

  8. The Galilean Satellites


    This composite includes the four largest moons of Jupiter which are known as the Galilean satellites. The Galilean satellites were first seen by the Italian astronomer Galileo Galilei in 1610. Shown from left to right in order of increasing distance from Jupiter, Io is closest, followed by Europa, Ganymede, and Callisto.The order of these satellites from the planet Jupiter helps to explain some of the visible differences among the moons. Io is subject to the strongest tidal stresses from the massive planet. These stresses generate internal heating which is released at the surface and makes Io the most volcanically active body in our solar system. Europa appears to be strongly differentiated with a rock/iron core, an ice layer at its surface, and the potential for local or global zones of water between these layers. Tectonic resurfacing brightens terrain on the less active and partially differentiated moon Ganymede. Callisto, furthest from Jupiter, appears heavily cratered at low resolutions and shows no evidence of internal activity.North is to the top of this composite picture in which these satellites have all been scaled to a common factor of 10 kilometers (6 miles) per picture element.The Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft acquired the Io and Ganymede images in June 1996, the Europa images in September 1996, and the Callisto images in November 1997.Launched in October 1989, the spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC.The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission

  9. Analysis of Visual Interpretation of Satellite Data

    Svatonova, H.


    Millions of people of all ages and expertise are using satellite and aerial data as an important input for their work in many different fields. Satellite data are also gradually finding a new place in education, especially in the fields of geography and in environmental issues. The article presents the results of an extensive research in the area of visual interpretation of image data carried out in the years 2013 - 2015 in the Czech Republic. The research was aimed at comparing the success rate of the interpretation of satellite data in relation to a) the substrates (to the selected colourfulness, the type of depicted landscape or special elements in the landscape) and b) to selected characteristics of users (expertise, gender, age). The results of the research showed that (1) false colour images have a slightly higher percentage of successful interpretation than natural colour images, (2) colourfulness of an element expected or rehearsed by the user (regardless of the real natural colour) increases the success rate of identifying the element (3) experts are faster in interpreting visual data than non-experts, with the same degree of accuracy of solving the task, and (4) men and women are equally successful in the interpretation of visual image data.

  10. The TAOS/STEP Satellite

    Edwards, David; Hosken, Robert


    The Technology for Autonomous Operational Survivability / Space Test Experiments Platform (TAOS/STEP) satellite was launched on a Taurus booster from Vandenberg Air Force Base into a nearly circular, 105 degree inclined orbit on March 13, 1994. The purpose of this satellite is twofold: 1) to test a new concept in multiple procurements of fast-track modular satellites and 2) to test a suite of Air Force Phillips Laboratory payloads in space. The TAOS payloads include the Microcosm Autonomous N...

  11. Living antennas on communication satellites

    Lumholt, Michael


    Crises change the global pattern of communication. The communications problems occur because the satellites are optimized to cover specific geographic areas, and these areas cannot be altered once the satellites are in Earth orbit. An effective solution to the problem is to equip communication...... satellites with "living" antennas that can adjust their radiation coverage areas according to the new demands. The development of living antennas is, therefore, among the focus areas identified and supported by the European Space Agency, ESA....

  12. Research



    Feb 17, 2012 ... This is an Open Access article distributed under the terms of the Creative ..... However, this system has great potential to negatively affect access to ... Dr. Samuel Yaw Opoku: Defining the Concept and Research Design; ...

  13. Research



    Apr 26, 2016 ... Management of biomedical waste in two medical laboratories in Bangui, Central ... Research .... Central African Republic Ministry of Health and corresponding ethics ..... In CAR, the management of BW remains embryonic. It is.

  14. Research



    Aug 28, 2015 ... Ethiopia, 2Bahir Dar Regional Health Research Laboratory Center, Department ... of Public Health, 4Institute of Medical Microbiology and Epidemiology of Infectious .... active ingredient x 10,000 dilution rate of product): 0.1%.

  15. Research



    Mar 11, 2011 ... ... to General Organization of Teaching Hospitals and Institutes, Egypt, 2Department of .... Ethiopia at Max-Burger Research Institute, Leipzig, Germany ... [22] than Croatia (50%), Australia (53%), Thailand (41%), Italy (32.6%), ...

  16. Research

    7, No. 1 AJHPE. Research. A comprehensive approach to curriculum evaluation is deemed ... While evaluators are guided by the experiences of using different methods, ..... provided a follow-up in-depth exploration of the quantitative results.

  17. Research

    ... community in the design, conduct and/or evaluation of these activities. ... During Phase I of the mixed-methods research design, data were collected by ... A questionnaire survey was administered to all students registered for ... Data analysis.

  18. Research



    Feb 3, 2016 ... Published in partnership with the African Field Epidemiology Network (AFENET). ( .... What is known about this topic ... India Co-ordinated Research Project. Ministry .... African Journal of Biotechnology. 2005 ...

  19. Research



    Dec 6, 2011 ... Asia indicate a high incidence of Kikuchi lymphadenitis [6]. However ... It is believed that information derived from this study will be of immense value to the attending physician and also form a baseline data for future research.

  20. Research

    judicious use of current best evidence in making decisions about the care of individual ... [5] This highlights that teaching research methodology is inclined ... to evidence-based practice in final-year undergraduate physiotherapy students.

  1. Research

    curricula to address health systems changes and challenges .... Likert scale questions were used, along with open-ended qualitative questions. ... Clear communicator: Able to communicate important aspects of theory, research findings clearly ...

  2. researchers

    levels who is fluent in only Afrikaans and English. Differences in race .... The lack of knowledge of a particular vernacular often places a researcher firmly as an ..... discourse of African American women', Black women in the academy. Promises.

  3. Research


    May 6, 2014 ... Methods. The researchers used an exploratory, sequential mixed-method design, ... This design is useful to explore a topic, using qualitative ... interview a Delphi questionnaire was used to gather additional quantitative.

  4. Research

    Research. Clinical teaching is a technique used in the education of nurses. It ... learnt in a contextualised learning environment, which should support them in their ..... development of continuing professional development strategies. This study ...

  5. Research



    Mar 3, 2016 ... radiation therapy [9, 10]. The signs of obstructive ... year's undergraduate medical student: socio-demographic including age (in years), sex. .... awareness and enhance further research in this domain. Conclusion. Patients ...

  6. Research

    Mathematics Teaching, 1973


    Implications for teachers from Piagetian-oriented piagetian-oriented research on problem solving reported in an article by Eleanor Duckworth are presented. Edward de Bono's Children Solve Problems,'' a collection of examples, is also discussed. (MS)

  7. Research



    Apr 29, 2016 ... performance hence workplace training is tied to achieving organizational aims and objectives. .... Ethical consideration: Permission to conduct research was sought from the County ..... Everybody Business: Strengthening.

  8. Operational evapotranspiration based on Earth observation satellites

    Gellens-Meulenberghs, Françoise; Ghilain, Nicolas; Arboleda, Alirio; Barrios, Jose-Miguel


    Geostationary satellites have the potential to follow fast evolving atmospheric and Earth surface phenomena such those related to cloud cover evolution and diurnal cycle. Since about 15 years, EUMETSAT has set up a network named 'Satellite Application Facility' (SAF, to complement its ground segment. The Land Surface Analysis (LSA) SAF ( is devoted to the development of operational products derived from the European meteorological satellites. In particular, an evapotranspiration (ET) product has been developed by the Royal Meteorological Institute of Belgium. Instantaneous and daily integrated results are produced in near real time and are freely available respectively since the end of 2009 and 2010. The products cover Europe, Africa and the Eastern part of South America with the spatial resolution of the SEVIRI sensor on-board Meteosat Second Generation (MSG) satellites. The ET product algorithm (Ghilain et al., 2011) is based on a simplified Soil-Vegetation-Atmosphere transfer (SVAT) scheme, forced with MSG derived radiative products (LSA SAF short and longwave surface fluxes, albedo). It has been extensively validated against in-situ validation data, mainly FLUXNET observations, demonstrating its good performances except in some arid or semi-arid areas. Research has then been pursued to develop an improved version for those areas. Solutions have been found in reviewing some of the model parameterizations and in assimilating additional satellite products (mainly vegetation indices and land surface temperature) into the model. The ET products will be complemented with related latent and sensible heat fluxes, to allow the monitoring of land surface energy partitioning. The new algorithm version should be tested in the LSA-SAF operational computer system in 2016 and results should become accessible to beta-users/regular users by the end of 2016/early 2017. In

  9. Trends in mobile satellite communication

    Johannsen, Klaus G.; Bowles, Mike W.; Milliken, Samuel; Cherrette, Alan R.; Busche, Gregory C.


    Ever since the U.S. Federal Communication Commission opened the discussion on spectrum usage for personal handheld communication, the community of satellite manufacturers has been searching for an economically viable and technically feasible satellite mobile communication system. Hughes Aircraft Company and others have joined in providing proposals for such systems, ranging from low to medium to geosynchronous orbits. These proposals make it clear that the trend in mobile satellite communication is toward more sophisticated satellites with a large number of spot beams and onboard processing, providing worldwide interconnectivity. Recent Hughes studies indicate that from a cost standpoint the geosynchronous satellite (GEOS) is most economical, followed by the medium earth orbit satellite (MEOS) and then by the low earth orbit satellite (LEOS). From a system performance standpoint, this evaluation may be in reverse order, depending on how the public will react to speech delay and collision. This paper discusses the trends and various mobile satellite constellations in satellite communication under investigation. It considers the effect of orbital altitude and modulation/multiple access on the link and spacecraft design.

  10. Magnetic Satellite Missions and Data

    Olsen, Nils; Kotsiaros, Stavros


    Although the first satellite observations of the Earth’s magnetic field were already taken more than 50 years ago, continuous geomagnetic measurements from space are only available since 1999. The unprecedented time-space coverage of this recent data set opened revolutionary new possibilities...... for exploring the Earth’s magnetic field from space. In this chapter we discuss characteristics of satellites measuring the geomagnetic field and report on past, present and upcoming magnetic satellite missions. We conclude with some basics about space magnetic gradiometry as a possible path for future...... exploration of Earth’s magnetic field with satellites....

  11. Satellite Communications: The Indian Scenario

    Dr. Ranjit Singh


    Full Text Available India has launched as many as 73 Indian satellites as of today since its first attempt in 1975. Besides serving traditional markets of telephony and broadcasting, satellites are on the frontiers of advanced applications as telemedicine, distance learning, environment monitoring, remote sensing, and so on. Satellite systems are optimized for services such as Internet access, virtual private networks and personal access. Costs have been coming down in recent years to the point where satellite broadband is becoming competitive. This article is an attempt to view this important topic from Indian perspective. India’s Project GAGAN, GPS Aided Geo Augmented Navigation is discussed.

  12. Business Use of Satellite Communications.

    Edelson, Burton I.; Cooper, Robert S.


    Reviews business communications development and discusses business applications of satellite communications, system technology, and prospects for future developments in digital transmission systems. (JN)

  13. Declassified Intelligence Satellite Photographs



    Declassified photographs from U.S. intelligence satellites provide an important worldwide addition to the public record of the Earth’s land surface. This imagery was released to the National Archives and Records Administration (NARA) and the U.S. Geological Survey (USGS) in accordance with Executive Order 12951 on February 23, 1995. The NARA has the original declassified film and a viewing copy. The USGS has another copy of the film to complement the Landsat archive.The declassified collection involves more than 990,000 photographs taken from 1959 through 1980 and was released on two separate occasions: February 1995 (Declass 1) and September 2002 (Declass 2). The USGS copy is maintained by the Earth Resources Observation and Science (EROS) Center, near Sioux Falls, South Dakota. Both the NARA and EROS provide public access to this unique collection that extends the record of land-surface change back another decade from the advent of the Landsat program that began satellite operations in 1972.

  14. The power relay satellite

    Glaser, Peter E.

    The availability and use of renewable energy sources compatible with reducing risks to the global environment are key to sustainable development. Large-scale, renewable energy resources at undeveloped or underutilized sites are potentially available on several continents. The Power Relay Satellite (PRS) concept has the potential to access these remote energy resources by coupling primary electricity generation from terrestrial transmission lines. A global PRS network can be envisioned to provide a high degree of flexibility for supplying energy demands worldwide with wireless power transmitted from sites on Earth to geosynchronous orbit and then reflected to receivers interfacing with terrestrial power transmision networks. Past developments in wireless power transmission (WPT) are reviewed and recent successful results are noted. The origins of the PRS concept, and a possible configuration are discussed, principles of WPT at microwave frequencies, functional requirements, and system design contraints are outlined, and space transportation concepts presented. PRS assessments including applicable technologies, economic projections, and societal issues are highlighted. It is concluded that the PRS provides a promising option to access renewable resources at great distances from major markets, and represents an important stage in the future development in the future of solar power satellites.

  15. Monitoring of wetlands Ecosystems using satellite images

    Dabrowska-Zielinska, K.; Gruszczynska, M.; Yesou, H.; Hoscilo, A.

    Wetlands are very sensitive ecosystems, functioning as habitat for many organisms. Protection and regeneration of wetlands has been the crucial importance in ecological research and in nature conservation. Knowledge on biophysical properties of wetlands vegetation retrieved from satellite images will enable us to improve monitoring of these unique areas, very often impenetrable. The study covers Biebrza wetland situated in the Northeast part of Poland and is considered as Ramsar Convention test site. The research aims at establishing of changes in biophysical parameters as the scrub encroachment, lowering of the water table, and changes of the farming activity caused ecological changes at these areas. Data from the optical and microwave satellite images collected for the area of Biebrza marshland ecosystem have been analysed and compared with the detailed soil-vegetation ground measurements conducted in conjunction with the overflights. Satellite data include Landsat ETM, ERS-2 ATSR and SAR, SPOT VEGETATION, ENVISAT MERIS and ASAR, and NOAA AVHRR. From the optical data various vegetation indices have been calculated, which characterize the vegetation surface roughness, its moisture conditions and stage of development. Landsat ETM image has been used for classification of wetlands vegetation. For each class of vegetation various moisture indices have been developed. Ground data collected include wet and dry biomass, LAI, vegetation height, and TDR soil moisture. The water cloud model has been applied for retrieval of soil vegetation parameters taking into account microwave satellite images acquired at VV, HV and HH polarisations at different viewing angles. The vegetation parameters have been used for to distinguish changes, which occurred at the area. For each of the vegetation class the soil moisture was calculated from microwave data using developed algorithms. Results of this study will help mapping and monitoring wetlands with the high spatial and temporal

  16. Inter-satellite links for satellite autonomous integrity monitoring

    Rodríguez-Pérez, Irma; García-Serrano, Cristina; Catalán Catalán, Carlos; García, Alvaro Mozo; Tavella, Patrizia; Galleani, Lorenzo; Amarillo, Francisco


    A new integrity monitoring mechanisms to be implemented on-board on a GNSS taking advantage of inter-satellite links has been introduced. This is based on accurate range and Doppler measurements not affected neither by atmospheric delays nor ground local degradation (multipath and interference). By a linear combination of the Inter-Satellite Links Observables, appropriate observables for both satellite orbits and clock monitoring are obtained and by the proposed algorithms it is possible to reduce the time-to-alarm and the probability of undetected satellite anomalies.Several test cases have been run to assess the performances of the new orbit and clock monitoring algorithms in front of a complete scenario (satellite-to-satellite and satellite-to-ground links) and in a satellite-only scenario. The results of this experimentation campaign demonstrate that the Orbit Monitoring Algorithm is able to detect orbital feared events when the position error at the worst user location is still under acceptable limits. For instance, an unplanned manoeuvre in the along-track direction is detected (with a probability of false alarm equals to 5 × 10-9) when the position error at the worst user location is 18 cm. The experimentation also reveals that the clock monitoring algorithm is able to detect phase jumps, frequency jumps and instability degradation on the clocks but the latency of detection as well as the detection performances strongly depends on the noise added by the clock measurement system.

  17. Gigabit Satellite Network for NASA's Advanced Communication Technology Satellite (ACTS)

    Hoder, Douglas; Bergamo, Marcos


    The advanced communication technology satellite (ACTS) gigabit satellite network provides long-haul point-to-point and point-to-multipoint full-duplex SONET services over NASA's ACTS. at rates up to 622 Mbit/s (SONET OC-12), with signal quality comparable to that obtained with terrestrial fiber networks. Data multiplexing over the satellite is accomplished using time-division multiple access (TDMA) techniques coordinated with the switching and beam hopping facilities provided by ACTS. Transmissions through the satellite are protected with Reed-Solomon encoding. providing virtually error-free transmission under most weather conditions. Unique to the system are a TDMA frame structure and satellite synchronization mechanism that allow: (a) very efficient utilization of the satellite capacity: (b) over-the-satellite dosed-loop synchronization of the network in configurations with up to 64 ground stations: and (c) ground station initial acquisition without collisions with existing signalling or data traffic. The user interfaces are compatible with SONET standards, performing the function of conventional SONET multiplexers and. as such. can be: readily integrated with standard SONET fiber-based terrestrial networks. Management of the network is based upon the simple network management protocol (SNMP). and includes an over-the-satellite signalling network and backup terrestrial internet (IP-based) connectivity. A description of the ground stations is also included.

  18. Building Technological Capability within Satellite Programs in Developing Countries

    Wood, Danielle Renee

    Global participation in space activity is growing as satellite technology matures and spreads. Countries in Africa, Asia and Latin America are creating or reinvigorating national satellite programs. These countries are building local capability in space through technological learning. They sometimes pursue this via collaborative satellite development projects with foreign firms that provide training. This phenomenon of collaborative satellite development projects is poorly understood by researchers of technological learning and technology transfer. The approach has potential to facilitate learning, but there are also challenges due to misaligned incentives and the tacit nature of the technology. Perspectives from literature on Technological Learning, Technology Transfer, Complex Product Systems and Product Delivery provide useful but incomplete insight for decision makers in such projects. This work seeks a deeper understanding of capability building through collaborative technology projects by conceiving of the projects as complex, socio-technical systems with architectures. The architecture of a system is the assignment of form to execute a function along a series of dimensions. The research questions explore the architecture of collaborative satellite projects, the nature of capability building during such projects, and the relationship between architecture and capability building. The research design uses inductive, exploratory case studies to investigate six collaborative satellite development projects. Data collection harnesses international field work driven by interviews, observation, and documents. The data analysis develops structured narratives, architectural comparison and capability building assessment. The architectural comparison reveals substantial variation in project implementation, especially in the areas of project initiation, technical specifications of the satellite, training approaches and the supplier selection process. The individual

  19. Research on Application Performance of Vehicle-mounted Station of Satellite Mobile Communication%卫星移动通信车载站应用性能研究



    在对各类卫星移动通信系统性能分析比较的基础上,从系统造价和可实现程度的角度考虑,同步静止轨道(GEO)系统更适合于区域覆盖卫星移动通信系统,卫星移动通信车载站(简称动中通)是实现地面卫星移动通信系统的关键设备。给出了动中通系统设计中卫星转发器带宽占用率和功率占用率的计算,对动中通站型能力和天线口径的选取进行了分析和讨论,并结合相关计算给出了动中通站型和天线选取的建议。%Based on the system performance comparison among some kinds of satellite mobile communication systems and the consideration of the cost and the extent of realization,the GEO system is more propitious to regional satellite mobile communication system. Vehicle-mounted station of satellite mobile communication is the key device to realize land mobile satellite communication system. The calculation methods of occupancy rates of bandwidth and power of satellite transponder in mobile communication system design are described in this paper. How to choose the size of antenna and the type of the station is analyzed and discussed. Some suggestions are given for choosing antenna and type of the station.

  20. Research



    Feb 25, 2013 ... Of these 56 eyes, the visual acuity in 49 eyes (87.5%) improved with pinhole. Twenty seven pupils had ... ( Research ... primary basic 1 to 6 and aged 5 to 15 years were included in the study. The United ...

  1. Research

    collaboration, but also in less tangible ways affecting quality of research.[5] ... Methods. A 40-hour workshop in biostatistical reasoning was conducted ... test median score was 68% (IQR 62 - 76%), with p<0.0001 for the overall comparison of pre- v. post-scores. ... limitations of a traditional lecture-based mode of instruction.

  2. Research



    Mar 13, 2014 ... &Corresponding author: Dr. Oliver Ezechi, Clinical Sciences Division, Nigerian Institute of Medical Research, ... with Hepatitis B and C Virus infection in pregnant HIV positive Nigerians. ... Whether or not HCV directly impacts HIV disease ..... natural history, fibrosis, and impact of antiretroviral treatment:.

  3. Research

    understood in the profession, evolved from therapeutic activity (within a medi- cal model ... facilitate students' ability to examine institutional systems that hinder ..... don't have connections with each other … we went to the schools and were told ... for change or conduct action research projects that deal with occupational.

  4. Research



    Dec 11, 2015 ... ... Dschang, Cameroon, 2Division of Health Operations Research, Ministry of Public ... This is an Open Access article distributed under the terms of the Creative Commons ... not yet been investigated but may can be explained by weakness of .... Cameroonian market and why not apply for surveillance of.

  5. Research

    by teaching them skills on how to acquire and appraise knowledge for a particular ... [3] Similarities have been noted in the roles of lecturers that facilitate learning rather than ..... Student feedback related to facilitators of and barriers to learning. Facilitators of ... 'Sometimes time (clinical, research, social, sport) was limited.'.

  6. Research



    Aug 25, 2011 ... completely replaced animals with computer modeling, manikins and ... distribution, and reproduction in any medium, provided the original ... developed internal guidelines on the use of animals in research in 2004 [13]. ... Only one institution used human cell cultures as a replacement to live animal use.

  7. Research



    Aug 5, 2013 ... In 2007, The World Health Organization (WHO) recommended ... are taken nearer to the community through clinical outreach ... Sample size and Sampling procedure ... researchers shared and debated the way each of them understood .... this may involve selling off assets to get the money for transport.

  8. Research



    Apr 20, 2016 ... ... Journal - ISSN 1937-8688. This is an Open Access article distributed under the terms of the Creative ... diabetes mellitus, obesity, family history of premature CHD in a first ... was reviewed and approved by the Hospital's Research and Ethics .... apoptosis of peripheral adipocytes, decreased pre-adipocyte.

  9. Satellite ocean remote sensing at NOAA/NESDIS

    Bayler, Eric J.


    Satellite oceanography within the Center for Satellite Applications and Research (STAR) in National Oceanic and Atmospheric Administration"s (NOAA) National Environmental Satellite, Data, and Information Service (NESDIS) focuses on observation retrievals and applications to address the NOAA missions of environmental assessment, prediction, and stewardship. Satellite oceanography within NOAA/NESDIS is an end-to-end process, addressing user requirements, sensor design support, observation retrieval research and development, calibration, applications and product research and development, the transition of research to operations, continuing product validation, and operational user support. The breadth of scientific investigation encompasses three functional areas: satellite ocean sensors, ocean dynamics/data assimilation, and marine ecosystems/climate. A cross-cutting science team from these functional areas has been established for each core subject: sea-surface temperature, sea-surface height, sea-surface roughness, ocean color, ocean surface winds, and sea ice. These science teams pursue the science and issues end to end within the core subject, with the primary objective being the transition of research to operations. Data fusion opportunities between science teams are also pursued. Each science team area addresses the common themes of calibration/validation, data assimilation, climate, and operational oceanography. Experimental and operational products, as well as user support, are provided to the user community via the NOAA OceanWatch/CoastWatch program.

  10. Multicast Routing in Satellite Network

    郭惠玲; 宋姝; 李磊; 刘志涛; 郭鹏程


    There are some problems in the dual-layer satellite MPLs metworks to be composed of LEO and MEO. In order to solve the problems, this paper presents a plan by means of unicast LSP to implement multicast in the dual-layer satellite MPLs networks. It has advantages of saving space and reducing extra charge.

  11. Magnetic Satellite Missions and Data

    Olsen, Nils; Kotsiaros, Stavros


    for exploring the Earth’s magnetic field from space. In this chapter we discuss characteristics of satellites measuring the geomagnetic field and report on past, present and upcoming magnetic satellite missions. We conclude with some basics about space magnetic gradiometry as a possible path for future...

  12. The SPOT satellite

    Fouquet, J.-P.


    The background, objectives and data products of the French SPOT remote sensing satellite system are presented. The system, which was developed starting in 1978 with the subsequent participation of Sweden and Belgium, is based on a standard multimission platform with associated ground control station and a mission-specific payload, which includes two High-Resolution Visible range instruments allowing the acquisition of stereoscopic views from different orbits. Mission objectives include the definition of future remote sensing systems, the compilation of a cartographic and resources data base, the study of species discrimination and production forecasting based on frequent access and off-nadir viewing, the compilation of a stereoscopic data base, and platform and instrument qualification, for possible applications in cartography, geology and agriculture. Standard data products will be available at three levels of preprocessing: radiometric correction only, precision processing for vertical viewing, and cartographic quality processing.

  13. Satellite Control Laboratory

    Wisniewski, Rafal; Bak, Thomas


    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... of the laboratory is to conduct dynamic tests of the control and attitude determination algorithms during nominal operation and in abnormal conditions. Further it is intended to use SatLab for validation of various algorithms for fault detection, accommodation and supervisory control. Different mission objectives...... can be implemented in the laboratory, e.g. three-axis attitude control, slew manoeuvres, spins stabilization using magnetic actuation and/or reaction wheels. The spacecraft attitude can be determined applying magnetometer measurements...

  14. Direct Broadcast Satellite: Radio Program

    Hollansworth, James E.


    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.

  15. Sky alert! when satellites fail

    Johnson, Les


    How much do we depend on space satellites? Defense, travel, agriculture, weather forecasting, mobile phones and broadband, commerce...the list seems endless. But what would our live be like if the unimaginable happened and, by accident or design, those space assets disappeared? Sky Alert! explores what our world would be like, looking in turn at areas where the loss could have catastrophic effects. The book - demonstrates our dependence on space technology and satellites; - outlines the effect on our economy, defense, and daily lives if satellites and orbiting spacecraft were destroyed; - illustrates the danger of dead satellites, spent rocket stages, and space debris colliding with a functioning satellites; - demonstrates the threat of dramatically increased radiation levels associated with geomagnetic storms; - introduces space as a potential area of conflict between nations.

  16. Induction studies with satellite data

    Olsen, Nils


    analysis of the geomagnetic field is performed, and the Q-response, which is the transfer function between the internal (induced) and the external (inducing) expansion coefficients is determined for a specific frequency. In the second approach, known as the geomagnetic depth sounding method, the C....... This paper reviews and discusses the possibilities for induction studies using high-precision magnetic measurements from low-altitude satellites. The different methods and various transfer functions are presented, with special emphasis on the differences in analysing data from ground stations and from...... satellites. The results of several induction studies with scalar satellite data (from the POGO satellites) and with vector data (from the Magsat mission) demonstrate the ability to probe the Earth's conductivity from space. However, compared to the results obtained with ground data the satellite results...

  17. Level-2 product generation for the Swarm satellite constellation mission

    Olsen, Poul Erik Holmdahl; Tøffner-Clausen, Lars; Olsen, Nils

    In order to take advantage of the unique constellation aspect of ESA's Swarm constellation mission, considerably advanced data analysis tools have been developed. The Swarm ESL/SCARF (Satellite Constellation Application and Research Facility), a consortium of several research institutions, derives...

  18. Level-2 product generation for the Swarm satellite constellation mission

    Olsen, Poul Erik Holmdahl; Tøffner-Clausen, Lars; Olsen, Nils

    In order to take advantage of the unique constellation aspect of ESA's Swarm constellation mission, considerably advanced data analysis tools have been developed. The Swarm ESL/SCARF (Satellite Constellation Application and Research Facility), a consortium of several research institutions, derives...

  19. Satellite-based Tropical Cyclone Monitoring Capabilities

    Hawkins, J.; Richardson, K.; Surratt, M.; Yang, S.; Lee, T. F.; Sampson, C. R.; Solbrig, J.; Kuciauskas, A. P.; Miller, S. D.; Kent, J.


    Satellite remote sensing capabilities to monitor tropical cyclone (TC) location, structure, and intensity have evolved by utilizing a combination of operational and research and development (R&D) sensors. The microwave imagers from the operational Defense Meteorological Satellite Program [Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSMIS)] form the "base" for structure observations due to their ability to view through upper-level clouds, modest size swaths and ability to capture most storm structure features. The NASA TRMM microwave imager and precipitation radar continue their 15+ yearlong missions in serving the TC warning and research communities. The cessation of NASA's QuikSCAT satellite after more than a decade of service is sorely missed, but India's OceanSat-2 scatterometer is now providing crucial ocean surface wind vectors in addition to the Navy's WindSat ocean surface wind vector retrievals. Another Advanced Scatterometer (ASCAT) onboard EUMETSAT's MetOp-2 satellite is slated for launch soon. Passive microwave imagery has received a much needed boost with the launch of the French/Indian Megha Tropiques imager in September 2011, basically greatly supplementing the very successful NASA TRMM pathfinder with a larger swath and more frequent temporal sampling. While initial data issues have delayed data utilization, current news indicates this data will be available in 2013. Future NASA Global Precipitation Mission (GPM) sensors starting in 2014 will provide enhanced capabilities. Also, the inclusion of the new microwave sounder data from the NPP ATMS (Oct 2011) will assist in mapping TC convective structures. The National Polar orbiting Partnership (NPP) program's VIIRS sensor includes a day night band (DNB) with the capability to view TC cloud structure at night when sufficient lunar illumination exits. Examples highlighting this new capability will be discussed in concert with additional data fusion efforts.

  20. The Communications Satellite as Educational Tool.

    Long, Peter


    Drawing on the experiences of several countries, the author describes satellite technology, discusses the feasibility of satellite use in traditional educational institutions, and analyzes the role of satellites in social development. (SK)

  1. Polar-Orbiting Satellite (POES) Images

    National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from camera systems or radiometer instruments on satellites in orbit around the poles. Satellite campaigns include...

  2. The use of satellites in gravity field determination and model adjustment

    Visser, Petrus Nicolaas Anna Maria


    Methods to improve gravity field models of the Earth with available data from satellite observations are proposed and discussed. In principle, all types of satellite observations mentioned give information of the satellite orbit perturbations and in conjunction the Earth's gravity field, because the satellite orbits are affected most by the Earth's gravity field. Therefore, two subjects are addressed: representation forms of the gravity field of the Earth and the theory of satellite orbit perturbations. An analytical orbit perturbation theory is presented and shown to be sufficiently accurate for describing satellite orbit perturbations if certain conditions are fulfilled. Gravity field adjustment experiments using the analytical orbit perturbation theory are discussed using real satellite observations. These observations consisted of Seasat laser range measurements and crossover differences, and of Geosat altimeter measurements and crossover differences. A look into the future, particularly relating to the ARISTOTELES (Applications and Research Involving Space Techniques for the Observation of the Earth's field from Low Earth Orbit Spacecraft) mission, is given.

  3. Stereoscopic observations from meteorological satellites

    Hasler, A. F.; Mack, R.; Negri, A.

    The capability of making stereoscopic observations of clouds from meteorological satellites is a new basic analysis tool with a broad spectrum of applications. Stereoscopic observations from satellites were first made using the early vidicon tube weather satellites (e.g., Ondrejka and Conover [1]). However, the only high quality meteorological stereoscopy from low orbit has been done from Apollo and Skylab, (e.g., Shenk et al. [2] and Black [3], [4]). Stereoscopy from geosynchronous satellites was proposed by Shenk [5] and Bristor and Pichel [6] in 1974 which allowed Minzner et al. [7] to demonstrate the first quantitative cloud height analysis. In 1978 Bryson [8] and desJardins [9] independently developed digital processing techniques to remap stereo images which made possible precision height measurement and spectacular display of stereograms (Hasler et al. [10], and Hasler [11]). In 1980 the Japanese Geosynchronous Satellite (GMS) and the U.S. GOES-West satellite were synchronized to obtain stereo over the central Pacific as described by Fujita and Dodge [12] and in this paper. Recently the authors have remapped images from a Low Earth Orbiter (LEO) to the coordinate system of a Geosynchronous Earth Orbiter (GEO) and obtained stereoscopic cloud height measurements which promise to have quality comparable to previous all GEO stereo. It has also been determined that the north-south imaging scan rate of some GEOs can be slowed or reversed. Therefore the feasibility of obtaining stereoscopic observations world wide from combinations of operational GEO and LEO satellites has been demonstrated. Stereoscopy from satellites has many advantages over infrared techniques for the observation of cloud structure because it depends only on basic geometric relationships. Digital remapping of GEO and LEO satellite images is imperative for precision stereo height measurement and high quality displays because of the curvature of the earth and the large angular separation of the

  4. Research of Early Warning Satellite Threat Assessment Based on Threat Degree Function%基于威胁度函数的预警卫星威胁评估研究

    张安理; 李智; 张雅声; 王庆文


    预警卫星作为导弹作战中重要的天基威胁源之一,目前对其评估多为效能评估,并没有从威胁的角度开展评估。通过对预警卫星威胁要素进行分析与提取,提出了一种基于威胁度函数的威胁评估方法。该方法综合了静态性能与作战状态的各个方面,使指挥员能够比较准确地把握预警卫星对导弹作战的威胁程度,从而为指挥员指挥决策提供依据。通过实例计算验证了该评估方法的可行性和有效性。%For early warning satellite,as one of the important space-based threat in the missile combat, now its effectiveness evaluation of early warning satellite was made,but was not for threat assessment. Through the analysis of the threat of early warning satellite elements and extract,we put forward a threat assessment method based on threat degree function.This method combined the static indicators and opera-tional status.It allowed the commander to grasp the degree of the threat of early warning satellite more ac-curately,which provided the basis for commander’s decision.The feasibility and effectiveness of this method were proved by a practical example.

  5. 环境减灾卫星遥感宏观监测应用评价研究%Research on the application of remote sensing macro- monitoring technology of the environment and disaster mitigation satellite

    胡凤伟; 胡龙华; 李琦


    文章介绍了环境减灾卫星的基本情况,结合环境减灾卫星遥感数据(HJ-1)在黑龙江省土地利用宏观监测中的实际应用,针对HJ-1数据的生产流程及生产方法进行了详述,对土地利用遥感宏观监测技术路线进行了研究,并通过高分辨率卫星遥感影像数据对宏观监测成果及其质量进行精度评价与验证,建立一套基于HJ-1数据的土地资源调查监测技术方法与流程,为在全国范围内广泛应用环境减灾卫星数据积累经验和技术方法。%The author makes a brief introduction on the environmental and disaster mtigation satellite. This thesis details the gen- erating processes and methods of I-IJ - 1 satellite data, with a practical situation of using HJ - 1 satellite date to monitor the land utilization in Heilongjiang Province ; studies the remote sensing macro - monitoring technique ; performs precision evaluation and verification of the monitoring results as well as the qualities via remote sensing image data in high - resolution ; establishes a set of monitoring techniques and processes for land resource investigation based on HJ - 1 data, laying a foundation for the extensive use of the environmental and disaster mtigation satellite data in China.

  6. Theory of satellite geodesy applications of satellites to geodesy

    Kaula, William M


    The main purpose of this classic text is to demonstrate how Newtonian gravitational theory and Euclidean geometry can be used and developed in the earth's environment. The second is to collect and explain some of the mathematical techniques developed for measuring the earth by satellite.Book chapters include discussions of the earth's gravitational field, with special emphasis on spherical harmonies and the potential of the ellipsoid; matrices and orbital geometry; elliptic motion, linear perturbations, resonance, and other aspects of satellite orbit dynamics; the geometry of satellite obser

  7. Handbook of satellite orbits from Kepler to GPS

    Capderou, Michel


    Fifty years after Sputnik, artificial satellites have become indispensable monitors in many areas, such as economics, meteorology, telecommunications, navigation and remote sensing. The specific orbits are important for the proper functioning of the satellites. This book discusses the great variety of satellite orbits, both in shape (circular to highly elliptical) and properties (geostationary, Sun-synchronous, etc.). This volume starts with an introduction into geodesy. This is followed by a presentation of the fundamental equations of mechanics to explain and demonstrate the properties for all types of orbits. Numerous examples are included, obtained through IXION software developed by the author. The book also includes an exposition of the historical background that is necessary to help the reader understand the main stages of scientific thought from Kepler to GPS. This book is intended for researchers, teachers and students working in the field of satellite technology. Engineers, geographers and all those...

  8. 3-dimensional current collection model. [of Tethered Satellite System 1

    Hwang, Kai-Shen; Shiah, A.; Wu, S. T.; Stone, N.


    A three-dimensional, time dependent current collection model of a satellite has been developed for the TSS-1 system. The system has been simulated particularly for the Research of Plasma Electrodynamics (ROPE) experiment. The Maxwellian distributed particles with the geomagnetic field effects are applied in this numerical simulation. The preliminary results indicate that a ring current is observed surrounding the satellite in the equatorial plane. This ring current is found between the plasma sheath and the satellite surface and is oscillating with a time scale of approximately 1 microsec. This is equivalent to the electron plasma frequency. An hour glass shape of electron distribution was observed when the viewing direction is perpendicular to the equatorial plane. This result is consistent with previous findings from Linson (1969) and Antoniades et al. (1990). Electrons that are absorbed by the satellite are limited from the background ionosphere as indicated by Parker and Murphy (1967).

  9. Thermal rocketing and the Laser Geodynamic Satellite (LAGEOS-1)

    Miller, W.A.


    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory. LAGEOS is the most accurately tracked satellite in orbit. It is a totally passive, dense spherical satellite covered with 426 cube corner reflectors. Besides its great utility in measuring the Earth`s length of day and polar wobble, this satellite can be used to measure, for the first time, the general relativistic frame-dragging effect. Of the five dominant error sources in such an experiment, the largest one involves surface interaction of thermal forces (thermal rocketing) and its influence on the orbital nodal precession. The project objective was to enhance an already available theoretical model (computer code) developed at Los Alamos based on new optical-spin data obtained at the University of Maryland. The project objective was met and the enhanced code will serve as the new spin-dynamics model for future LAGEOS satellite missions.

  10. Sampling errors in rainfall estimates by multiple satellites

    North, Gerald R.; Shen, Samuel S. P.; Upson, Robert


    This paper examines the sampling characteristics of combining data collected by several low-orbiting satellites attempting to estimate the space-time average of rain rates. The several satellites can have different orbital and swath-width parameters. The satellite overpasses are allowed to make partial coverage snapshots of the grid box with each overpass. Such partial visits are considered in an approximate way, letting each intersection area fraction of the grid box by a particular satellite swath be a random variable with mean and variance parameters computed from exact orbit calculations. The derivation procedure is based upon the spectral minimum mean-square error formalism introduced by North and Nakamoto. By using a simple parametric form for the spacetime spectral density, simple formulas are derived for a large number of examples, including the combination of the Tropical Rainfall Measuring Mission with an operational sun-synchronous orbiter. The approximations and results are discussed and directions for future research are summarized.

  11. Research and Implementation of Narrow-band Satellite Transceiver Based on GNU Radio%基于GNU Radio的窄带卫星收发信机研究与实现

    林广荣; 林新荣; 高时汉; 褚庆昕


    Software defined radio based on general-purpose processor adopts advanced programming language for signal processing, which could help reuse the hardware in different products and improve development efifciency. This paper presented an engineering scheme of narrow-band satellite transceiver on open source GNU Radio platform, and further validated its feasibility by communication testing over actual GEO satellite. The practice provided a new solution for testing terminal equipment, which would aid in the development of satellite communication product.%基于通用处理器的软件无线电技术,使用高级程序语言实现无线电通信中的信号处理功能,这能够更好地复用硬件平台和提升开发效率。文章基于开源的软件无线电平台GNU Radio,给出了一种软件无线电架构的窄带卫星收发信机的工程实现方案,并通过实际上星测试验证了方案的可行性,可为卫星通信产品的研发提供测试和验证的途径。

  12. Recent Korean R&D in Satellite Communications

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

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

  13. 基于光载波抑制调制的星间微波光子下变频研究%Research on inter-satellite microwave photonic frequency down conversion based on optical carrier suppression modulation

    李轩; 赵尚弘; 张薇; 朱子行; 韩磊; 赵静


    To solve the problem of optical handling of microwave signal in satellite communication,the inter-satellite microwave photonic frequency down conversion system is modeled,two parallel dual-electrode Mach-Zehnder modulators based on optical carrier suppression modulation are utilized to modulate the uplink microwave signal received by satellite and the local oscillator signal produced in satellite,respectively,and the microwave signal is optically amplified,transmitted and frequency-down converted in the inter-satellite optical link.The output signal and noise of system are analyzed with Bessel expansion,the local oscillator signal power is optimized,and the effects of modulator bias phase drift,phase shifter error and emission optical power on the system performance are simulated.The results show that the deterioration of output carrier to noise ratio (CNR) is under 0.05 dB while the modulator bias phase drift is less than 5 ℃,the output CNR deterioration is under 0.02 dB while the phase shifter error is less than 5 ℃,and the frequency down conversion system has high stability.When the emission optical power is 10.48 dB,the system output CNR is 31.33 dB,which can meet the practical requirement.The inter-satellite microwave photonic frequency down conversion system can be applied to the optical handling of microwave signal in the future satellite optical communications.%针对卫星通信中微波信号光学处理问题,建立了星间微波光子下变频系统模型,采用两个双电极马赫-曾德尔调制器(DE-MZM)并联形式,以光载波抑制(DCS)方式实现了星间微波信号的光域放大、传输和下变频.利用贝塞尔函数展开分析了下变频系统中信号和各噪声分量,对射频本振信号功率进行了优化,仿真研究了调制器直流偏置漂移、移相器相移误差和发射光功率对系统性能的影响.结果表明,调制器直流偏置相位漂移小于5℃时输出载噪比(CNR)恶化小于0.05 dB

  14. Multi-mission Satellite Management

    Jamilkowski, M. L.; Teter, M. A.; Grant, K. D.; Dougherty, B.; Cochran, S.


    NOAA's next-generation environmental satellite, the Joint Polar Satellite System (JPSS) replaces the current Polar-orbiting Operational Environmental Satellites (POES). JPSS satellites carry sensors which collect meteorological, oceanographic, climatological, and solar-geophysical observations of the earth, atmosphere, and space. The first JPSS satellite was launched in 2011 and is currently NOAA's primary operational polar satellite. The JPSS ground system is the Common Ground System (CGS), and provides command, control, and communications (C3) and data processing (DP). A multi-mission system, CGS provides combinations of C3/DP for numerous NASA, NOAA, DoD, and international missions. In preparation for the next JPSS satellite, CGS improved its multi-mission capabilities to enhance mission operations for larger constellations of earth observing satellites with the added benefit of streamlining mission operations for other NOAA missions. CGS's multi-mission capabilities allows management all of assets as a single enterprise, more efficiently using ground resources and personnel and consolidating multiple ground systems into one. Sophisticated scheduling algorithms compare mission priorities and constraints across all ground stations, creating an enterprise schedule optimized to mission needs, which CGS executes to acquire the satellite link, uplink commands, downlink and route data to the operations and data processing facilities, and generate the final products for delivery to downstream users. This paper will illustrate the CGS's ability to manage multiple, enterprise-wide polar orbiting missions by demonstrating resource modeling and tasking, production of enterprise contact schedules for NOAA's Fairbanks ground station (using both standing and ad hoc requests), deconflicting resources due to ground outages, and updating resource allocations through dynamic priority definitions.

  15. Congestion control and routing over satellite networks

    Cao, Jinhua

    Satellite networks and transmissions find their application in fields of computer communications, telephone communications, television broadcasting, transportation, space situational awareness systems and so on. This thesis mainly focuses on two networking issues affecting satellite networking: network congestion control and network routing optimization. Congestion, which leads to long queueing delays, packet losses or both, is a networking problem that has drawn the attention of many researchers. The goal of congestion control mechanisms is to ensure high bandwidth utilization while avoiding network congestion by regulating the rate at which traffic sources inject packets into a network. In this thesis, we propose a stable congestion controller using data-driven, safe switching control theory to improve the dynamic performance of satellite Transmission Control Protocol/Active Queue Management (TCP/AQM) networks. First, the stable region of the Proportional-Integral (PI) parameters for a nominal model is explored. Then, a PI controller, whose parameters are adaptively tuned by switching among members of a given candidate set, using observed plant data, is presented and compared with some classical AQM policy examples, such as Random Early Detection (RED) and fixed PI control. A new cost detectable switching law with an interval cost function switching algorithm, which improves the performance and also saves the computational cost, is developed and compared with a law commonly used in the switching control literature. Finite-gain stability of the system is proved. A fuzzy logic PI controller is incorporated as a special candidate to achieve good performance at all nominal points with the available set of candidate controllers. Simulations are presented to validate the theory. An effocient routing algorithm plays a key role in optimizing network resources. In this thesis, we briefly analyze Low Earth Orbit (LEO) satellite networks, review the Cross Entropy (CE

  16. The satellite total solar irradiance database

    Willson, R. C.


    A precise knowledge of the total solar irradiance (TSI) over time is essential to understanding the physics of solar luminosity variation and its impact on the Earth in the form of climate change. A National Research Council study found that sustained trends as small as 0.25% per century were the most likely forcing for ‘little ice age’ climate minima during the 12th - 19th centuries. Recent phenomenological analyses of TSI observations and proxies indicate that TSI variation is an important climate change forcing on many timescales including the industrial era. The profound sociological and economic implications of understanding the relative climate change contributions of natural and anthropogenic forcings makes it essential that the satellite TSI database be precisely sustained into the foreseeable future. There are currently three satellite TSI monitoring experiments in operation: SOHO/VIRGO, ACRIMSAT/ACRIM3 and SORCE/TIM, in order of deployment (1996, 2000 and 2003, resp.). Results reported on their ‘native scales show the same basic variations in TSI over time, yet some smaller variations detected by ACRIM3 are less well defined or absent in the results of VIRGO and TIM. There is also a scale difference issue: TIM results are 0.35% lower than those of ACRIM3 and VIRGO, outside the ± 0.1% uncertainty bounds predicted for ACRIM3 and VIRGO, and well outside TIM’s ± 0.01% uncertainty design goal. TIM’s failure to achieve 0.01% uncertainty in flight demonstrates that the TSI monitoring paradigm shift of relying on measurement accuracy rather than a redundant/overlap strategy to provide long term traceability cannot be realized with current ‘ambient temperature’ technology. The only viable monitoring approach for the foreseeable future continues to be the redundant/overlap strategy that has provided the 31 year satellite TSI database to date with useful traceability. Intercomparisons of flight experiments at their levels of mutual precision can

  17. Satellite communications principles and applications

    Calcutt, David


    Satellites are increasingly used for global communications, as well as for radio and television transmissions. With the growth of mobile communications, and of digital technology, the use of satellite systems is set to expand substantially and already all students of electronics or communications engineering must study the subject.This book steers a middle path between offering a basic understanding of the process of communication by satellite and the methodology used; and the extensive mathematical analysis normally adopted in similar texts. It presents the basic concepts, using as mu

  18. Advanced Communications Technology Satellite (ACTS)

    Gedney, Richard T.; Schertler, Ronald J.


    The NASA Advanced Communications Technology Satellite (ACTS) was conceived to help maintain U.S. leadership in the world's communications-satellite market. This experimental satellite is expected to be launched by NASA in 1992 and to furnish the technology necessary for establishing very small aperture terminal digital networks which provide on-demand full-mesh connectivity, and 1.544-MBPS services with only a single hop. Utilizing on-board switching and processing, each individual voice or data circuit can be separately routed to any location in the network. This paper provides an overview of the ACTS and discusses the value of the technology for future communications systems.

  19. The french educational satellite arsene

    Danvel, M.; Escudier, B.

    ARSENE (Ariane, Radio-amateur, Satellite pour l'ENseignement de l'Espace) is a telecommunications satellite for Amateur Space Service. Its main feature is that more than 100 students from French engineering schools and universities have been working since 1979 for definition phase and satellite development. The highest IAF awards has been obtained by "ARSENE students" in Tokyo (1980) and Rome (1981). The French space agency, CNES and French aerospace industries are supporting the program. The European Space Agency offered to place ARSENE in orbit on the first Ariane mark IV launch late 1985.

  20. ISDN - The case for satellites

    Pelton, Joseph N.; McDougal, Patrick J.


    The Integrated Services Digital Network (ISDN) holds much promise for both suppliers and users of telecommunications in the near future. This article examines the role of satellites in this new ISDN environment and emphasizes several advantages of satellites in the ongoing evolution to an all-digital world. In specific, the role of Intelsat, the global satellite system, is discussed with emphasis on Intelsat's digital services which today can offer all the characteristics and standards of ISDN in a flexible, cost-efficient manner.

  1. Leucocytes, cytokines and satellite cells

    Paulsen, Gøran; Mikkelsen, Ulla Ramer; Raastad, Truls


    -damaging exercise', primarily eccentric exercise. We review the evidence for the notion that the degree of muscle damage is related to the magnitude of the cytokine response. In the third and final section, we look at the satellite cell response to a single bout of eccentric exercise, as well as the role...... damage. With the exception of IL-6, the sources of systemic cytokines following exercise remain unclear The satellite cell response to severe muscle damage is related to regeneration, whereas the biological significance of satellite cell proliferation after mild damage or non-damaging exercise remains...

  2. Genetic Algorithms for Satellite Scheduling Problems

    Fatos Xhafa


    Full Text Available Recently there has been a growing interest in mission operations scheduling problem. The problem, in a variety of formulations, arises in management of satellite/space missions requiring efficient allocation of user requests to make possible the communication between operations teams and spacecraft systems. Not only large space agencies, such as ESA (European Space Agency and NASA, but also smaller research institutions and universities can establish nowadays their satellite mission, and thus need intelligent systems to automate the allocation of ground station services to space missions. In this paper, we present some relevant formulations of the satellite scheduling viewed as a family of problems and identify various forms of optimization objectives. The main complexities, due highly constrained nature, windows accessibility and visibility, multi-objectives and conflicting objectives are examined. Then, we discuss the resolution of the problem through different heuristic methods. In particular, we focus on the version of ground station scheduling, for which we present computational results obtained with Genetic Algorithms using the STK simulation toolkit.

  3. A native IP satellite communications system

    Koudelka, O.; Schmidt, M.; Ebert, J.; Schlemmer, H.; Kastner-Puschl, S.; Riedler, W.


    ≪ In the framework of ESA's ARTES-5 program the Institute of Applied Systems Technology (Joanneum Research) in cooperation with the Department of Communications and Wave Propagation has developed a novel meshed satellite communications system which is optimised for Internet traffic and applications (L*IP—Local Network Interconnection via Satellite Systems Using the IP Protocol Suite). Both symmetrical and asymmetrical connections are supported. Bandwidth on demand and guaranteed quality of service are key features of the system. A novel multi-frequency TDMA access scheme utilises efficient methods of IP encapsulation. In contrast to other solutions it avoids legacy transport network techniques. While the DVB-RCS standard is based on ATM or MPEG transport cells, the solution of the L*IP system uses variable-length cells which reduces the overhead significantly. A flexible and programmable platform based on Linux machines was chosen to allow the easy implementation and adaptation to different standards. This offers the possibility to apply the system not only to satellite communications, but provides seamless integration with terrestrial fixed broadcast wireless access systems. The platform is also an ideal test-bed for a variety of interactive broadband communications systems. The paper describes the system architecture and the key features of the system.

  4. Planetary satellites - an update

    Beatty, J. K.


    General features of all known planetary satellites in the system are provided, and attention is focused on prominent features of several of the bodies. Titan has an atmosphere 1.5 times earth's at sea level, a well a a large body of liquid which may be ethane, CH4, and disolved N2. Uranus has at least five moons, whose masses have recently been recalculated and determined to be consistent with predictions of outer solar system composition. Io's violent volcanic activity is a demonstration of the conversion of total energy (from Jupiter) to heat, i.e., interior melting and consequent volcanoes. Plumes of SO2 have been seen and feature temperatures of up to 650 K. Enceladus has a craterless, cracked surface, indicating the presence of interior ice and occasional breakthroughs from tidal heating. Hyperion has a chaotic rotation, and Iapetus has one light and one dark side, possibly from periodic collisions with debris clouds blasted off the surface of the outer moon Phoebe.

  5. Hubble Space Telescope satellite

    Mitchell, R. E.


    The Hubble Space Telescope, named for the American astronomer Edwin Powell Hubble, will be the largest and most powerful astronomical instrument ever orbited. Placed above the obscuring effects of the earth's atmosphere in a 600-km orbit, this remotely-controlled, free-flying satellite observatory will expand the terrestrial-equivalent resolution of the universe by a factor of seven, or a volumetric factor of 350. This telescope has a 2.4-m primary mirror and can accommodate five scientific instruments (cameras, spectrographs and photometers). The optics are suitable for a spectral range from 1100 angstrom to 1 mm wavelength. With a projected service life of fifteen years, the spacecraft can be serviced on-orbit for replacement of degraded systems, to insert advanced scientific instruments, and to reboost the telescope from decayed altitudes. The anticipated image quality will be a result of extremely precise lambda/20 optics, stringent cleanliness, and very stable pointing: jitter will be held to less than 0.01 arcsecond for indefinite observation periods, consistent with instrument apertures as small as 0.1 arcsecond.

  6. Testing command and control of the satellites in formation flight

    Gheorghe, Popan; Gheorghe, Gh. Ion; Gabriel, Todoran


    The topics covered in the paper are mechatronic systems for determining the distance between the satellites and the design of the displacement system on air cushion table for satellites testing. INCDMTM has the capability to approach the collaboration within European Programms (ESA) of human exploration of outer space through mechatronic systems and accessories for telescopes, mechatronics systems used by the launchers, sensors and mechatronic systems for the robotic exploration programs of atmosphere and Mars. This research has a strong development component of industrial competitiveness many of the results of space research have direct applicability in industrial fabrication.

  7. Investigation on Satellite-borne High-power Solid-state Power Amplifier Technology and Experiment

    Wu Xiao-po; Zhao Hai-yang; Xi Song-tao


    Based on the research and development efforts of satellite-borne lumped solid-state transmitters, the design of a satellite-borne high-power microwave amplifier module is introduced. Focusing on satellite-borne applications, aspects of the high-power density thermal design, multipactor proof design, EMC design and so on, which are critical technologies for a solid-state power amplifier, are discussed. Subsequently, experiments are used to verify the concept.

  8. Economically sustainable public security and emergency network exploiting a broadband communications satellite

    Lawal, Lasisi Salami


    The research contributes to work in Rapid Deployment of a National Public Security and Emergency Communications Network using Communication Satellite Broadband. Although studies in Public Security Communication networks have examined the use of communications satellite as an integral part of the Communication Infrastructure, there has not been an in-depth design analysis of an optimized regional broadband-based communication satellite in relation to the envisaged service coverage area, with l...

  9. Investigation on Satellite-borne High-power Solid-state Power Amplifier Technology and Experiment

    Wu Xiao-po


    Full Text Available Based on the research and development efforts of satellite-borne lumped solid-state transmitters, the design of a satellite-borne high-power microwave amplifier module is introduced. Focusing on satellite-borne applications, aspects of the high-power density thermal design, multipactor proof design, EMC design and so on, which are critical technologies for a solid-state power amplifier, are discussed. Subsequently, experiments are used to verify the concept.

  10. Satellite Applications for K-12 Geoscience Education

    Mooney, M.; Ackerman, S.; Lettvin, E.; Emerson, N.; Whittaker, T. M.


    This presentation will highlight interactive on-line curriculum developed at the Cooperative Institute for Meteorological Satellite Studies (CIMSS) at the University of Wisconsin in Madison. CIMSS has been on the forefront of educational software design for over two decades, routinely integrating on-line activities into courses on satellite remote sensing. In 2006, CIMSS began collaborating with education experts and researchers from the University of Washington to create an NSF-funded distance learning course for science teachers called Satellite Applications for Geoscience Education. This course includes numerous web-based learning activities, including a distance education tool called VISITview which allows instructors to connect with multiple students simultaneously to conduct a lesson. Developed at CIMSS to facilitate training of National Weather Service forecasters economically and remotely, VISITview is especially effective for groups of people discussing and analyzing maps or images interactively from many locations. Along with an on-line chat function, VISITview participants can use a speaker phone or a networked voice-enabled application to create a learning environment similar to a traditional classroom. VISITview will be used in two capacities: first, instructors will convey topics of current relevance in geoscience disciplines via VISITview. Second, the content experts will participate in "virtual visits" to the classrooms of the educators who take the course for full credit. This will enable scientists to interact with both teachers and students to answer questions and discuss exciting or inspiring examples that link satellite data to their areas of research. As long as a school has Internet access, an LCD projector and a speakerphone, VISITview sessions can be shared with an entire classroom. The geoscientists who developed material for the course and conducting VISITview lectures include a geologist from the University of Wisconsin-Richland, an

  11. Commercial satellite broadcasting for Europe

    Forrest, J. R.


    A review is presented of the current television broadcasting situation in European countries, which involves a varied mix of terrestrial VHF or UHF systems and cable networks. A small market has emerged in Europe for receivers using the low-power telecommunications satellite transmission between the program providers and cable network companies. This is expected to change with the launch of medium-power pan-European telecommunication satellites (e.g. ASTRA, EUTELSAT II), which are now directly addressing the market of home reception. DBS (direct broadcast satellite) in the UK, using the D-MAC transmission standard, will offer three additional television channels, data broadcasting services, and a planned evolution to compatible forms of wide-screen, high-definition television. Comments are given on receiver and conditional access system standardization. Some views are expressed on satellite broadcasting as part of an overall broadcasting framework for the future.

  12. Virtual Satellite Integration Environment Project

    National Aeronautics and Space Administration — An integrated environment for rapid design studies of small satellite missions will be developed. This environment will be designed to streamline processes at the...

  13. Virtual Satellite Integration Environment Project

    National Aeronautics and Space Administration — Advatech Pacific proposes to develop a Virtual Satellite Integration Environment (VSIE) for the NASA Ames Mission Design Center. The VSIE introduces into NASA...

  14. Satellite Teleconferencing in the Caribbean.

    Sankar, Hollis C.


    Discusses the need for, and the development, use, and future trends of, the University of the West Indies Distance Teaching Experiment, which utilizes telephone and communications satellite technology teleconferencing to extend educational opportunities to the peoples of the Caribbean. (MBR)

  15. Geography with the environmental satellites

    J.P. Gastellu Etchegorry


    Full Text Available Coarse spatial resolution, high temporal frequency data from the earth polar orbiting (NOAA. HACMM, Nimbus, etc. satellites and from the geostationary (GOES. Meteosat, and GMS satellites are presented to demonstrate their utility for monitoring terrestrial and atmospheric processes. The main characteristics of these ,satellites and of the instruments on board are reviewed. In order to be useful for environmental assessments. the remotely sensed data must be processed (atmospheric and geometric corrections, etc.. The NOAA Center provides a wide range of already processed data. such as meteorological. oceanic, hydrologic and vegetation products; o rough description of these preprocessed data is given in this article. Finally, some examples of applicotions in Southeast Asia and especially in Indonesia, are described, i.e.: agroecosystem, drought and oceanic monitoring. The paper concludes that coarse resolution, high temporal frequency ,satellite data are very valuable for environmental studies. the emphasis being laid on the improve. ment of the crop and drought assessment programmes.

  16. Comparison of HRDI wind measurements with radar and rocket observations

    Burrage, M.D.; Skinner, W.R.; Marshall, A.R.; Hays, P.B.; Lieberman, R.S.; Gell, D.A.; Ortland, D.A.; Morton, Y.T.; Wu, D.L.; Franke, S.J.; Schmidlin, F.J.; Vincent, R.A.


    This paper reports wind measurements in the mesosphere and lower thermosphere made by the high resolution doppler imager (HRDI) on board the upper atmosphere research satellite (UARS). These measurements are correlated with ground based radar and rocket measurements. The HRDI makes measurements by observing doppler shifts in molecular oxygen lines. The intercomparison helps to validate the remote sensing results, helps to verify the on board calibration system, and also gives a common measurement which other measurements systems can be compared against.

  17. Kalman Filter Chemical Data Assimilation: A Case Study in January 1992

    Lary, D. J.; Khattatov, B.; Atlas, Robert; Mussa, H.


    This paper describes a Kalman filter chemical data assimilation system and its use for analysing a vertical atmospheric profile during January 1992. The vertical profile was at an equivalent PV latitude (phi(sub e)) of 55 deg S and consisted of 21 potential temperature (theta) levels spaced equally in log(theta) between 400 K and 2000 K. This equivalent latitude was chosen as it was well observed during January 1992 by instruments on board the Upper Atmosphere Research Satellite (UARS).

  18. women Contrlbute to Satellite Technology


    IN the early morning of August 14, 1992, at the Xichang satellite launching center, China Central Television Station was about to do a live, worldwide broadcast on the launching of an Australian communications satellite made by the United States. With the order of the commander, "Ignition," people could watch the white rocket rise, pierce the blue sky and race toward the space with a long flaming tail trailing behind it.

  19. Existence of undiscovered Uranian satellites

    Boice, D.C.


    Structure in the Uranian ring system as observed in recent occultations may contain indirect evidence for the existence of undiscovered satellites. Using the Alfven and Arrhenius (1975, 1976) scenario for the formation of planetary systems, the orbital radii of up to nine hypothetical satellites interior to Miranda are computed. These calculations should provide interesting comparisons when the results from the Voyager 2 encounter with Uranus are made public. 15 refs., 1 fig., 1 tab.

  20. Radio interferometry and satellite tracking

    Kawase, Seiichiro


    Worldwide growth of space communications has caused a rapid increase in the number of satellites operating in geostationary orbits, causing overcrowded orbits. This practical resource is designed to help professionals overcome this problem. This timely book provides a solid understanding of the use of radio interferometers for tracking and monitoring satellites in overcrowded environments. Practitioners learn the fundamentals of radio interferometer hardware, including antennas, receiving equipment, signal processing and phase detection, and measurement accuracies. This in-depth volume describ

  1. Spanish Earth Observation Satellite System

    Borges, A.; Cerezo, F.; Fernandez, M.; Lomba, J.; Lopez, M.; Moreno, J.; Neira, A.; Quintana, C.; Torres, J.; Trigo, R.; Urena, J.; Vega, E.; Vez, E.


    The Spanish Ministry of Industry, Tourism and Trade (MITyC) and the Ministry of Defense (MoD) signed an agreement in 2007 for the development of a "Spanish Earth Observation Satellite System" based, in first instance, on two satellites: a high resolution optical satellite, called SEOSAT/Ingenio, and a radar satellite based on SAR technology, called SEOSAR/Paz. SEOSAT/Ingenio is managed by MITyC through the Centre for the Development of Industrial Technology (CDTI), with technical and contractual support from the European Space Agency (ESA). HISDESA T together with the Spanish Instituto Nacional de Técnica Aeroespacial (INTA, National Institute for Aerospace Technology) will be responsible for the in-orbit operation and the commercial operation of both satellites, and for the technical management of SEOSAR/Paz on behalf of the MoD. In both cases EADS CASA Espacio (ECE) is the prime contractor leading the industrial consortia. The ground segment development will be assigned to a Spanish consortium. This system is the most important contribution of Spain to the European Programme Global Monitoring for Environment and Security, GMES. This paper presents the Spanish Earth Observation Satellite System focusing on SEOSA T/Ingenio Programme and with special emphasis in the potential contribution to the ESA Third Party Missions Programme and to the Global Monitoring for Environment and Security initiative (GMES) Data Access.

  2. Satellite medical centers project

    Aggarwal, Arvind


    World class health care for common man at low affordable cost: anywhere, anytime The project envisages to set up a national network of satellite Medical centers. Each SMC would be manned by doctors, nurses and technicians, six doctors, six nurses, six technicians would be required to provide 24 hour cover, each SMC would operate 24 hours x 7 days. It would be equipped with the Digital telemedicine devices for capturing clinical patient information and investigations in the form of voice, images and data and create an audiovisual text file - a virtual Digital patient. Through the broad band connectivity the virtual patient can be sent to the central hub, manned by specialists, specialists from several specialists sitting together can view the virtual patient and provide a specialized opinion, they can see the virtual patient, see the examination on line through video conference or even PCs, talk to the patient and the doctor at the SMC and controlle capturing of information during examination and investigations of the patient at the SMC - thus creating a virtual Digital consultant at the SMC. Central hub shall be connected to the doctors and consultants in remote locations or tertiary care hospitals any where in the world, thus creating a virtual hub the hierarchical system shall provide upgradation of knowledge to thedoctors in central hub and smc and thus continued medical education and benefit the patient thru the world class treatment in the smc located at his door step. SMC shall be set up by franchisee who shall get safe business opportunity with high returns, patients shall get Low cost user friendly worldclass health care anywhere anytime, Doctors can get better meaningful selfemplyment with better earnings, flexibility of working time and place. SMC shall provide a wide variety of services from primary care to world class Global consultation for difficult patients.

  3. Satellite de-orbiting via controlled solar radiation pressure

    Deienno, Rogerio; Sanchez, Diogo Merguizo; de Almeida Prado, Antonio Fernando Bertachini; Smirnov, Georgi


    The goal of the present research was to study the use of solar radiation pressure to place a satellite in an orbit that makes it to re-enter the atmosphere of the Earth. This phase of the mission is usual, since the orbital space around the Earth is crowded and all satellites have to be discarded after the end of their lifetimes. The technique proposed here is based on a device that can increase and decrease the area-to-mass ratio of the satellite when it is intended to reduce its altitude until a re-entry point is reached. Equations that predict the evolution of the eccentricity and semi-major axis of the orbit of the satellite are derived and can be used to allow the evaluation of the time required for the decay of the satellite. Numerical simulations are made, and they show the time required for the decay as a function of the area-to-mass ratio and the evolution of the most important orbital elements. The results show maps that indicate regions of fast decays as a function of the area-to-mass ratio and the initial inclination of the orbit of the satellite. They also confirmed the applicability of the equations derived here. The numerical results showed the role played by the evection and the Sun-synchronous resonances in the de-orbiting time.

  4. IIth AMS Conference on Satellite Meteorology and Oceanography.

    Velden, Christopher; Digirolamo, Larry; Glackin, Mary; Hawkins, Jeffrey; Jedlovec, Gary; Lee, Thomas; Petty, Grant; Plante, Robert; Reale, Anthony; Zapotocny, John


    The American Meteorological Society (AMS) held its 11th Conference on Satellite Meteorology and Oceanography at the Monona Terrace Convention Center in Madison, Wisconsin, during 15-18 October 2001. The purpose of the conference, typically held every 18 months, is to promote a forum for AMS membership, international scientists, and student members to present and discuss the latest advances in satellite remote sensing for meteorological and oceanographical applications. This year, surrounded by inspirational designs by famed architect Frank Lloyd Wright, the meeting focused on several broad topics related to remote sensing from space, including environmental applications of land and oceanic remote sensing, climatology and long-term satellite data studies, operational applications, radiances and retrievals, and new technology and methods. A vision of an increasing convergence of satellite systems emerged that included operational and research satellite programs and interdisciplinary user groups.The conference also hosted NASA's Electronic Theater, which was presented to groups of middle and high school students totaling over 5500. It was truly a successful public outreach event. The conference banquet was held on the final evening, where a short tribute to satellite pioneer Verner Suomi was given by Joanne Simpson. Suomi was responsible for establishing the Space Science and Engineering Center at the University of Wisconsin in Madison.

  5. Measuring snow and glacier ice properties from satellite

    KöNig, Max; Winther, Jan-Gunnar; Isaksson, Elisabeth


    Satellite remote sensing is a convenient tool for studying snow and glacier ice, allowing us to conduct research over large and otherwise inaccessible areas. This paper reviews various methods for measuring snow and glacier ice properties with satellite remote sensing. These methods have been improving with the use of new satellite sensors, like the synthetic aperture radar (SAR) during the last decade, leading to the development of new and powerful methods, such as SAR interferometry for glacier velocity, digital elevation model generation of ice sheets, or snow cover mapping. Some methods still try to overcome the limitations of present sensors, but future satellites will have much increased capability, for example, the ability to measure the whole optical spectrum or SAR sensors with multiple polarization or frequencies. Among the methods presented are the satellite-derived determination of surface albedo, snow extent, snow volume, snow grain size, surface temperature, glacier facies, glacier velocities, glacier extent, and ice sheet topography. In this review, emphasis is put on the principles and theory of each satellite remote sensing method. An extensive list of references, with an emphasis on studies from the 1990s, allows the reader to delve into specific topics.

  6. Satellite Attitude from a Raven Class Telescope


    Cache MATLAB was used as an interface to the jSim libraries, including orbit propagation, Earth Track determination, and satellite orientation methods...collection opportunities of the satellite. The combined software tool calculates the satellite orientation required to image the asset location... satellite orientation estimations, with only the photometric signatures with strong features being correctly estimated. The strong features that



    China placed 2 scientific experiment satellites into preset orbits atop a LM-4B launch vehicle on Sept. 9, 2004. A LM-4B blasted off at 7:14 am from Taiyuan Satellite Launch Center in Shanxi Province. Sources from the Xi'an Satellite Monitor and Control Center said that one satellite,

  8. China Launches First Ever Nano-satellite



    China successfully launched two scientific satellites, including a nano-satellite for the first time, heralding a breakthrough in space technology. A LM-2C rocket carrying Nano-Satellite I (NS-1), which weighs just 25kg and an Experiment Satellite I, weighing 204kg blasted off at 11:59 p.m. on April 18,

  9. Three Satellites to Be Launched on One Rocket in 2011


    Aspace storm observation project has recently been put into implementation. The project consists of three exploration satellites. One will operate in an orbit of proximity 700km altitude for scientific research in ionosphere and thermosphere, one in an orbit of 50,O00km for near earth magnetic sphere research and the last one in 150,O00km orbit for the research on solar winds outside the earth magnetic sphere.

  10. Fast Development Of China's Small Satellite Industry

    Sun Hongjin


    @@ China Spacesat Co., Ltd of China Academy of Space Technology (CAST) recently said, along with the successful launch of HJ-1A/B for the environment and disaster monitoring and forecasting small satellite constellation and after years of efforts, small satellite development technology has achieved fruitful results, and the development status has been greatly improved.China's small satellite technology has realized a great-leap-forward in development from a single satellite model to series model, from the satellite program to space industry. China has explored a development road for China's small satellite industrialization, and a modern small satellite development base has resulted.

  11. Research of on-board mixed optical/electric switching of GEO broadband multimedia satellite%通信卫星光电混合交换技术研究

    李瑞欣; 赵尚弘; 幺周石; 郑伟; 李勇军; 刘振霞


    On-board switching has been the development trend of satellite communication. There is electronic bottleneck in the development of on-board ATM switch, so the optical switch is the inevitable direction of future broadband multimedia satellite. The paper brings forward a scheme about on-board mixed optical/electronic switching of GEO, analyses the switching mode of the scheme, discusses the key techniques.%星上交换已成为卫星通信发展的趋势之一.星上ATM交换在发展过程中存在着电子瓶颈,星上光交换是未来宽带多媒体卫星的必然发展方向.提出了一种光电混合星上交换技术方案,对星上光交换的方式进行了分析,讨论了光电混合星上交换技术涉及的关键技术,对未来星上交换技术的发展进行了总结.

  12. 星载交换机中高性能队列管理器的研究与实现%Research and implementation of a high performance queue management equipment on the satellite onboard switch

    王孟磊; 施扬; 乔庐峰; 禹明刚


    针对星载交换机中硬件处理速度和存储器容量受限的情况,设计实现了一个高性能队列管理器.采用虚拟输出排队机制改善输入缓存中存在的队头阻塞问题;使用前向地址指针pre_addr和后向地址指针nxt addr控制信元的写入和读出.通过ModelSim SE行为级时序仿真可知,其能够达到星载交换机的队列时延要求,具有较高的交换性能及稳定性.%This paper implements a high performance queue management equipment due to the limitation of hardware procession speed and memory capacity on the satellite onboard switch. It utilizes virtual output queue(VOQ) to improve the HOL problem of input buffer, and control the writing and reading of a cell by implementing the previous address pointer (pre_addr) and the next address pointer (nxt_addr). The results of ModelSim SE behavioral timing simulation show that it satisfies the need of queue delay of the satellite onboard switch, and has high performance and stability.

  13. Satellite network robust QoS-aware routing

    Long, Fei


    Satellite Network Robust QoS-aware Routing presents a novel routing strategy for satellite networks. This strategy is useful for the design of multi-layered satellite networks as it can greatly reduce the number of time slots in one system cycle. The traffic prediction and engineering approaches make the system robust so that the traffic spikes can be handled effectively. The multi-QoS optimization routing algorithm can satisfy various potential user requirements. Clear and sufficient illustrations are also presented in the book. As the chapters cover the above topics independently, readers from different research backgrounds in constellation design, multi-QoS routing, and traffic engineering can benefit from the book.   Fei Long is a senior engineer at Beijing R&D Center of 54th Research Institute of China Electronics Technology Group Corporation.

  14. Shadow imaging of geosynchronous satellites

    Douglas, Dennis Michael

    Geosynchronous (GEO) satellites are essential for modern communication networks. If communication to a GEO satellite is lost and a malfunction occurs upon orbit insertion such as a solar panel not deploying there is no direct way to observe it from Earth. Due to the GEO orbit distance of ~36,000 km from Earth's surface, the Rayleigh criteria dictates that a 14 m telescope is required to conventionally image a satellite with spatial resolution down to 1 m using visible light. Furthermore, a telescope larger than 30 m is required under ideal conditions to obtain spatial resolution down to 0.4 m. This dissertation evaluates a method for obtaining high spatial resolution images of GEO satellites from an Earth based system by measuring the irradiance distribution on the ground resulting from the occultation of the satellite passing in front of a star. The representative size of a GEO satellite combined with the orbital distance results in the ground shadow being consistent with a Fresnel diffraction pattern when observed at visible wavelengths. A measurement of the ground shadow irradiance is used as an amplitude constraint in a Gerchberg-Saxton phase retrieval algorithm that produces a reconstruction of the satellite's 2D transmission function which is analogous to a reverse contrast image of the satellite. The advantage of shadow imaging is that a terrestrial based redundant set of linearly distributed inexpensive small telescopes, each coupled to high speed detectors, is a more effective resolved imaging system for GEO satellites than a very large telescope under ideal conditions. Modeling and simulation efforts indicate sub-meter spatial resolution can be readily achieved using collection apertures of less than 1 meter in diameter. A mathematical basis is established for the treatment of the physical phenomena involved in the shadow imaging process. This includes the source star brightness and angular extent, and the diffraction of starlight from the satellite



    China on Sept.25 recovered its 19th recoverable sci-tech experimental satellite 27 days after the satellite orbited in space. The satellite, which was launched on Aug.29 from the Jiuquan Satellite Launch Center in Gansu Province, northwest China, touched the ground at 7:55 a.m.on Sept.25. The satellite, atop a Long March 2C carrier rocket, is mainly for

  16. Lopsided Collections of Satellite Galaxies

    Kohler, Susanna


    You might think that small satellite galaxies would be distributed evenly around their larger galactic hosts but local evidence suggests otherwise. Are satellite distributions lopsided throughout the universe?Satellites in the Local GroupThe distribution of the satellite galaxies orbiting Andromeda, our neighboring galaxy, is puzzling: 21 out of 27 ( 80%) of its satellites are on the side of Andromeda closest to us. In a similar fashion, 4 of the 11 brightest Milky Way satellites are stacked on the side closest to Andromeda.It seems to be the case, then, that satellites around our pair of galaxies preferentially occupy the space between the two galaxies. But is this behavior specific to the Local Group? Or is it commonplace throughout the universe? In a recent study, a team of scientists led by Noam Libeskind (Leibniz Institute for Astrophysics Potsdam, Germany) set out to answer this question.Properties of the galaxies included in the authors sample. Left: redshifts for galaxy pairs. Right: Number of satellite galaxies around hosts. [Adapted from Libeskind et al. 2016]Asymmetry at LargeLibeskind and collaborators tested whether this behavior is common by searching through Sloan Digital Sky Survey observations for galaxy pairs that are similar to the Milky Way/Andromeda pair. The resulting sample consists of 12,210 pairs of galaxies, which have 46,043 potential satellites among them. The team then performed statistical tests on these observations to quantify the anisotropic distribution of the satellites around the host galaxies.Libeskind and collaborators find that roughly 8% more galaxies are seen within a 15 angle facing the other galaxy of a pair than would be expected in a uniform distribution. The odds that this asymmetric behavior is randomly produced, they show, are lower than 1 in 10 million indicating that the lopsidedness of satellites around galaxies in pairs is a real effect and occurs beyond just the Local Group.Caution for ModelingProbability that

  17. Jupiter small satellite montage


    A montage of images of the small inner moons of Jupiter from the camera onboard NASA's Galileo spacecraft shows the best views obtained of these moons during Galileo's 11th orbit around the giant planet in November 1997. At that point, Galileo was completing its first two years in Jupiter orbit--known as the Galileo 'prime mission'--and was about to embark on a successful two-year extension, called the Galileo Europa Mission. The top two images show the moon Thebe. Thebe rotates by approximately 50 degrees between the time these two images were taken, so that the same prominent impact crater is seen in both views; this crater, which has been given the provisional name Zethus, is near the point on Thebe that faces permanently away from Jupiter. The next two images show the moon Amalthea; they were taken with the Sun directly behind the observer, an alignment that emphasizes patterns of intrinsically bright or dark surface material. The third image from the top is a view of Amalthea's leading side, the side of the moon that 'leads' as Amalthea moves in its orbit around Jupiter. This image looks 'noisy' because it was obtained serendipitously during an observation of the Jovian satellite Io (Amalthea and Io shared the same camera frame but the image was exposed for bright Io rather than for the much darker Amalthea). The fourth image from the top emphasizes prominent 'spots' of relatively bright material that are located near the point on Amalthea that faces permanently away from Jupiter. The bottom image is a view of the tiny moon Metis. In all the images, north is approximately up, and the moons are shown in their correct relative sizes. The images are, from top to bottom: Thebe taken on November 7, 1997 at a range of 504,000 kilometers (about 313,000 miles); Thebe on November 7, 1997 at a range of 548,000 kilometers (about 340,000 miles); Amalthea on November 6, 1997 at a range of about 650,000 kilometers (about 404,000 miles); Amalthea on November 7, 1997 at a

  18. Weather Satellite Enterprise Information Chain

    Jamilkowski, M. L.; Grant, K. D.; Miller, S. W.; Cochran, S.


    NOAA & NASA are acquiring the next-generation civilian operational weather satellite: Joint Polar Satellite System (JPSS). Contributing the afternoon orbit & ground system (GS) to replace current NOAA POES Satellites, its sensors will collect meteorological, oceanographic & climatological data. The JPSS Common Ground System (CGS), consisting of C3 and IDP segments, is developed by Raytheon. It now flies the Suomi National Polar-orbiting Partnership (S-NPP) satellite, transferring data between ground facilities, processing them into environmental products for NOAA weather centers, and expanding to support JPSS-1 in 2017. As a multi-mission system, CGS provides combinations of C3, data processing, and product delivery for numerous NASA, NOAA, DoD and international missions.The CGS provides a wide range of support to a number of missions: Command and control and mission management for the S-NPP mission today, expanding this support to the JPSS-1 satellite mission in 2017 Data acquisition for S-NPP, the JAXA's Global Change Observation Mission - Water (GCOM-W1), POES, and the Defense Meteorological Satellite Program (DMSP) and Coriolis/WindSat for the DoD Data routing over a global fiber network for S-NPP, JPSS-1, GCOM-W1, POES, DMSP, Coriolis/WindSat, NASA EOS missions, MetOp for EUMETSAT and the National Science Foundation Environmental data processing and distribution for S-NPP, GCOM-W1 and JPSS-1 The CGS plays a key role in facilitating the movement and value-added enhancement of data all the way from satellite-based sensor data to delivery to the consumers who generate forecasts and produce watches and warnings. This presentation will discuss the information flow from sensors, through data routing and processing, and finally to product delivery. It will highlight how advances in architecture developed through lessons learned from S-NPP and implemented for JPSS-1 will increase data availability and reduce latency for end user applications.

  19. China Satellite Navigation Conference (CSNC) 2012 Proceedings : The 3rd China Satellite Navigation Conference

    Liu, Jingnan; Yang, Yuanxi; Fan, Shiwei


    Proceedings of the 3rd China Satellite Navigation Conference (CSNC2012) presents selected research papers from CSNC2012, held on 15-19 May in Guanzhou, China. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou system especially. They are divided into 9 topics to match the corresponding sessions in CSNC2012, which broadly covered key topics in GNSS. Readers can learn about the BeiDou system and keep abreast of the latest advances in GNSS techniques and applications. SUN Jiadong is the Chief Designer of the Compass/BeiDou system, and the Academician of Chinese Academy of Sciences; LIU Jingnan is a professor at Wuhan University, and the Academician of Chinese Academy of Engineering; YANG Yuanxi is a professor at China National Administration of GNSS and Applications, and the Academician of Chinese Academy of Sciences; FAN Shiwei öis a researcher on satellite navigation.

  20. Traffic model for advanced satellite designs and experiments for ISDN services

    Pepin, Gerard R.; Hager, E. Paul


    The data base structure and fields for categorizing and storing Integrated Services Digital Network (ISDN) user characteristics is outlined. This traffic model data base will be used to exercise models of the ISDN Advanced Communication Satellite to determine design parameters and performance for the NASA Satellite Communications Applications Research (SCAR) Program.

  1. Dutch Micro Systems Technology for the Next Generation of Small Satellites

    Gill, E.; Monna, G.L.E.; Scherpen, J.M.A.; Verhoeven, C.J.M.


    Advanced microelectronics and Micro Systems Technology (MST) enable an increased functional performance of small satellites with decreased demands on mass, size and power. The research and development cluster MISAT stimulates the design and development of advanced small satellite platforms based on

  2. A Highly Secure Identity-Based Authenticated Key-Exchange Protocol for Satellite Communication

    Zhong Yantao, [No Value; Ma Jianfeng, [No Value


    In recent years, significant improvements have been made to the techniques used for analyzing satellite communication and attacking satellite systems. In 2003, a research team at Los Alamos National Laboratory, USA, demonstrated the ease with which civilian global positioning system (GPS) spoofing a

  3. A Highly Secure Identity-Based Authenticated Key-Exchange Protocol for Satellite Communication

    Zhong Yantao, [No Value; Ma Jianfeng, [No Value


    In recent years, significant improvements have been made to the techniques used for analyzing satellite communication and attacking satellite systems. In 2003, a research team at Los Alamos National Laboratory, USA, demonstrated the ease with which civilian global positioning system (GPS) spoofing a

  4. Formation flying within a constellation of nano-satellites the QB50 mission

    Gill, E.K.A.; Sundaramoorthy, P.; Bouwmeester, J.; Zandbergen, B.; Reinhard, R.


    QB50 is a mission establishing an international network of 50 nano-satellites for multi-point, in-situ measurements in the lower thermosphere and re-entry research. As part of the QB50 mission, the Delft University of Technology intends to contribute two nano-satellites both being equipped with a hi

  5. Dutch Micro Systems Technology for the Next Generation of Small Satellites

    Gill, E.; Monna, G.L.E.; Scherpen, J.M.A.; Verhoeven, C.J.M.


    Advanced microelectronics and Micro Systems Technology (MST) enable an increased functional performance of small satellites with decreased demands on mass, size and power. The research and development cluster MISAT stimulates the design and development of advanced small satellite platforms based on

  6. Implementation of space satellite remote sensing programs in developing countries (Ecuador)

    Segovia, A.


    The current state of space satellite remote sensing programs in developing countries is discussed. Sensors being utilized and results obtained are described. Requirements are presented for the research of resources in developing countries. It is recommended that a work procedure be developed for the use of satellite remote sensing data tailored to the necessities of the different countries.

  7. Spectral Measurements of Geosynchronous Satellites During Glint Season

    Chun, F.; Tucker, R.; Weld, E.; Chun, F.; Tippets, R.

    During certain times of the year, stable geosynchronous (GEO) satellites are known to glint or exhibit a very bright specular reflection, which is easily observed through broadband photometric filters. The glints are typically brighter in the Johnson red filter compared to the Johnson blue filter. In previous years, USAFA cadets have developed and refined techniques to take, calibrate and process satellite spectral data taken using a diffraction grating on the USAFA 16-inch, f/8.2 telescope (slitless spectroscopy). To the best of our knowledge, we have not seen any published research on observing glints across the visible spectrum. We present research from an Air Force Academy senior physics capstone project on observing glints off of GEO satellites using slitless spectroscopy. We discuss the calibration of the measurements using solar analog and solar twin stars, as well as results of the spectra of a glinting GEO satellite. A key question is whether a GEO satellite glint is localized in wavelength or equally observed across the entire spectra.

  8. 云南电网应急通信车卫星数据通信解决方案研究%Research of Satellite Data Communication Solutions for Emergency Communication Vehicle in Yunnan Power Grid

    孙严智; 胡劲松; 刘宇明; 田之俊; 陈先富


    Yunnan is a province where natural disasters occur frequently, and disasters like earthquake and ice disaster take place frequently in recent years, so the emergency command and repair work of power grid face major challenges. To this end, the Yunnan power grid achieves two-way voice communications, two-way data communications, real-time video image acquisition and transmission and video conferencing through the introduction of emergency communication vehicle system. Among them, the voice, image and video communication mainly rely on satellite communications. However, the satellite link has the characteristics of long delay and high error rate, which leads to the decrease of TCP transmission performance, so that the data transmission is poor in real time. To solve this problem, this paper analyzes the existing satellite link TCP performance enhancement scheme . A solution which is suitable for the network architecture of emergency communication system in Yunnan power grid is proposed and the feasibility of the scheme is verified by testing.%云南是自然灾害多发省份,近年来,地震、冰灾等灾害频发,电网的应急指挥和抢修复电工作面临重大考验。为此,云南电网通过引入应急通信车系统实现双向语音通信、双向数据通信、现场视频图像实时采集及传输、视频会议功能,其现场应急语音、图像、视频通信主要依靠卫星通信开展。但卫星链路存在长时延、高误码等特性,导致传输控制协议(transmission control protocol,TCP)的传输性能明显下降,以至于数据传输的实时性较差。为解决这一问题,通过分析现有卫星链路TCP性能增强方案,提出一种符合云南电网应急通信系统网络架构的解决方案,通过测试,进一步验证该方案的可行性。

  9. A review of uses of satellite imagery in monitoring mangrove forests

    Rhyma Purnamasayangsukasih, P.; Norizah, K.; Ismail, Adnan A. M.; Shamsudin, I.


    Satellite image could provide much information of earth surfaces in a large scale in a short time, thus saving time. With the evolution and development of sensors providing satellite image, resolution of object captured enhanced with advance image processing techniques. In forestry, satellite image has been widely used for resources management, planning, monitoring, predicting, etc. However, the uses of satellite image are reported to be moderate and sometimes poor for mangrove forests due to homogenous species existed in salty and inundation areas. Many researches had been carried out to improve the uses of satellite imagery of either optical or radar data for mangrove forests. This paper reviews the uses of satellite imagery data in mangrove with the main focus of the literature related to mangroves monitoring.

  10. Stream Gauges and Satellite Measurements

    Alsdorf, D. E.


    Satellite measurements should not be viewed as a replacement for stream gauges. However, occasionally it is suggested that because satellite-based measurements can provide river discharge, a motivation for satellite approaches is an increasing lack of stream gauges. This is an argument for more stream gauges, but not necessarily for satellite measurements. Rather, in-situ and spaceborne methods of estimating discharge are complementary. Stream gauges provide frequent measurements at one point in the river reach whereas satellites have the potential to measure throughout all reaches but at orbital repeat intervals of days to weeks. The Surface Water and Ocean Topography satellite mission (SWOT) is an opportunity to further develop these complements. The motivation for SWOT, and indeed for any satellite based method of estimating discharge, should not be as a replacement for stream gauges. Scientific and application uses should motivate the measurements. For example, understanding floods with their dynamic water surfaces are best sampled from remote platforms that provide water surface elevations throughout the floodwave. As another example, today’s water and energy balance models are giving outputs at increasing spatial resolution and are making use of water surface elevations throughout the modeled basin. These models require a similar resolution in the calibrating and validating observations. We should also be aware of practical limitations. In addition to providing spatially distributed hydrodynamic measurements on rivers, SWOT will be able to measure storage changes in the estimated 30 million lakes in the world that are larger than a hectare. Knowing the storage changes in these lakes is especially important in certain regions such as the Arctic but gauging even a small fraction of these is impractical. Another motivator for satellite methods is that even in the presence of stream gauges, discharge data is not always well shared throughout all countries

  11. Chartering Launchers for Small Satellites

    Hernandez, Daniel

    The question of how to launch small satellites has been solved over the years by the larger launchers offering small satellites the possibility of piggy-backing. Specific fixtures have been developed and commercialized: Arianespace developed the ASAP interface, the USAF studied ESPA, NASA has promoted Shuttle launch possibilities, Russian authorities and companies have been able to find solutions with many different launchers... It is fair to say that most launcher suppliers have worked hard and finally often been able to find solutions to launch most small satellites into orbit. It is also true, however, that most of these small satellites were technology demonstration missions capable of accepting a wide range of orbit and launch characteristics: orbit altitude and inclination, launch date, etc. In some cases the small satellite missions required a well-defined type of orbit and have therefore been obliged to hire a small launcher on which they were the prime passenger. In our paper we would like to propose an additional solution to all these possibilities: launchers could plan well in advance (for example about 3 years), trips to precisely defined orbits to allow potential passengers to organize themselves and be ready on the D-Day. On the scheduled date the chartered launcher goes to the stated orbit while on another date, another chartered launcher goes to another orbit. The idea is to organize departures for space like trains or airplanes leaving on known schedules for known destinations.

  12. Low Earth orbit communications satellite

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


    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. Satellite Tracking Astrometric Network (STAN)

    Vecchiato, Alberto; Gai, Mario


    The possibility of precise orbit tracking and determination of different types of satellites has been explored for at least some 25 years (Arimoto et al., 1990). Proposals in this sense made use mainly of astrometric observations, but multiple tracking techniques combining transfer and laser ranging was also suggested (Guo et al., 2009; Montojo et al., 2011), with different requirements and performances ranging from $\\sim100$~m to tenths of meters.In this work we explore the possible improvements and a novel implementation of a technique relying on large angle, high precision astrometry from ground for the determination of satellite orbits. The concept is based on combined observation of geostationary satellites and other near-Earth space objects from two or more telescopes, applying the triangulation principle over widely separated regions of the sky. An accuracy of a few $10^{-2}$~m can be attained with 1-meter-class telescopes and a field of vied of some arcminutes.We discuss the feasibility of the technique, some of the implementation aspects, and the limitations imposed by atmospheric turbulence. The potential benefits for satellite orbit control and navigation systems are presented, depending on the number and position of the contributing telescopes.We also discuss the possibility that, by reversing the roles of stars and satellites, the same kind of observations can be used for verification and maintenance of astrometric catalogs.

  14. Orbit Determination Using Satellite-to-Satellite Tracking Data


    Satellite-to-Satellite Tracking (SST) data can be used to determine the orbits of spacecraft in two ways. One is combined orbit determination, which combines SST data with ground-based tracking data and exploits the enhanced tracking geometry. The other is the autonomous orbit determination, which uses only SST. The latter only fits some particular circumstances since it suffers the rank defect problem in other circumstances. The proof of this statement is presented. The na ture of the problem is also investigated in order to find an effective solution. Several methods of solution are discussed. The feasibility of the methods is demonstrated by their apphcation to a simulation.

  15. 星载原子钟数据预处理的方法研究%Research on the Methods of Preprocessing the Satellite-Borne Atomic Clocks Data

    李斌; 杨富春; 江峻毅


    Satellite-borne atomic clocks data preprocessing is the basis of atomic clocks performance analysis and clock forecasting,phase and frequency of data conversion and abnormal data analysis and processing methods are used to preprocess the clocks data, these methods can effectively guarantee the re-liability of the clocks data.%星载原子钟的数据预处理是进行原子钟性能分析和钟差预报的前提,本文主要利用相位数据和频率数据的转换和异常数据的分析处理方法对原子钟数据进行了预处理,有效的保证了数据的可靠性。

  16. Developing Geostationary Satellite Imaging at Lowell Observatory

    van Belle, G.


    Lowell Observatory operates the Navy Precision Optical Interferometer (NPOI), and owns & operates the Discovery Channel Telescope (DCT). This unique & necessary combination of facilities positions Lowell to develop a robust program of observing geostationary, GPS-plane, and other high-altitude (&1000mi) satellites. NPOI is a six-beam long-baseline optical interferometer, located in Flagstaff, Arizona; the facility is supported by a partnership between Lowell Observatory, the US Naval Observatory, and the Naval Research Laboratory. NPOI operates year-round in the visible with baselines between 8 and 100 meters (up to 432m is available), conducting programs of astronomical research and imaging technology development. NPOI is the only such facility as yet to directly observe geostationary satellites, enabling milliarcsecond resolution of these objects. To enhance this capability towards true imaging of geosats, an ongoing program of facility upgrades will be outlined. These upgrades include AO-assisted 1.0-m apertures feeding each beam line, and new near-infrared instrumentation on the back end. The large apertures will enable `at-will' observations of objects brighter than mK = 8:3 in the near-IR, corresponding to brighter than mV = 11:3 in the visible. At its core, the system is enabled by a `wavelength-baseline bootstrapping' approach discussed herein. A complementary pilot imaging study of visible speckle and aperture masked imaging at Lowell's 4.3-m DCT, for constraining the low-spatial frequency imaging information, is also outlined.

  17. Satellite-retrieval and modeling of glacier mass balance

    Ruyter de Wildt, Martijn Sybren de


    In this research project we use satellite measurements to infer the mean specific mass balance (Bm) of glaciers. Vatnajökull, the largest ice cap in Europe, is being used as a test-case because this ice cap has often been studied. Only one aspect of Vatnajökull has not been investigated so far, and

  18. A Constraint Based Approach for Building Operationally Responsive Satellites


    discipline specific software codes into a common environment. LLB team also uses MATLAB R© to integrate CAD tools such as Catia , Pro/Engineer with FE...satellite configuration through a Catia CAD tool. The LLB approach is similar to the approach discussed in this research because it provides a method

  19. Nozzle fabrication for Micro Propulsion of a Micro-Satellite

    Louwerse, M.C.; Jansen, Henricus V.; Groenendijk, M.N.W.; Elwenspoek, Michael Curt


    To enable formation flying of micro satellites, small sized propulsion systems are required. Our research focuses on the miniaturization of a feeding and thruster system by means of micro system technology (MST). Three fabrication methods have been investigated to make a conical converging-diverging

  20. Research on Receiving Technology Based on Blind Signal Separation for Satellite MIMO Communication System%基于盲分离的卫星MIMO系统接收技术研究

    辛吉荣; 万坚; 陈绍贺; 程建


    针对卫星MIMO(Multi-Input Multi-Output)通信系统,提出采用盲分离的思路对各卫星信号进行接收.考虑到盲分离性能易受噪声、混合矩阵病态性的影响,分析了噪声对接收性能影响最小时信道传输矩阵(即盲分离中的混合矩阵)应满足的条件,并给出了满足此条件的等距线阵的构建方式.通过计算机仿真分析了在此方式下,等距线阵的方位角、间距以及信号频率对盲分离接收的影响,最后得出对天线阵列建设具有一定指导意义的结论,为进一步进行实验奠定基础.%Methods of using blind signal processing was proposed to receive the communication signal in Satellite MIMO (Multi-Input Multi-Output) system. Since the receiving performance was affected by noise and illness of mixing matrix, the channel transfer matrix (also called mixing matrix in blind signal processing) that minimized the noise affection was analyzed. The relationship between the transfer matrix and the uniform linear array's parameter such as azimuth angle, distance between two adjacent antennas and the frequency was also analyzed by simulation. Final, some conclusions useful in designing an antenna array in satellite communication system were given out.

  1. The digital mapping of satellite images under no ground control and the distribution of landform, blue ice and meteorites in the Grove Mountains, Antarctica

    孙家抦; 霍东民; 周军其; 孙朝辉


    The colorful satellite image maps with the scale of 1∶100 000 were made by processing the parameters-on-satellite under the condition of no data of field surveying. The purpose is to ensure the smooth performance of the choice of expedition route, navigation and research task before the Chinese National Antarctic Research Expedition (CHINARE) first made researches on the Grove Mountains. Moreover, on the basis of the visual interpretation of the satellite image, we preliminarily analyze and discuss the relief and landform, blue ice and meteorite distribution characteristics in the Grove Mountains. Key words Grove Mountains, parameters-on-satellite, satellite image, digital mapping, blue ice, meteorites distribution.

  2. New Regional Satellite Positioning Constellation Scheme Discussion

    CHU Hai-bin; ZHANG Nai-tong; GU Xue-mai


    The characteristics of present "Beidou" satellite positioning system are analyzed. In order to perfect our country regional satellite positioning system, the idea of "Beidou" geosychronous earth orbit (GEO) satellites combined with some middle earth orbit (MEO) satellites constellation is put forward. The details of general satellite constellation optimized method are described, using this method the multiple positioning constellation design results are gained. And those results belong to two type of schems, one is 2 GEO plus some MEO satellites and the other is 3 GEO plus some MEO satellites. Through simulation and comparison, among those multiple design results, final optimized regional positioning constellation is given. In order to check the chosen constellation cover performance, the position dilution of precision(PDOP) is calculated, and with satellite constellation simulation software Satlab many coverage performances of the chosen constellation substellar point track, elevation, azimuth and visible satellites number changing situation are also simulated.

  3. ERTS-A satellite imagery

    Colvocoresses, Alden P.


    The first satellite designed to survey the Earth's resources is scheduled to be launched in 1972. This satellite, known as ERTS-A, will telemeter frames of imagery each covering 100-nautical-mile squares of the Earth. Except for the internal anomalies in the sensor system, the imagery, after being properly scaled, rectified, and controlled, may be considered an orthographic view of the Earth and used as a planimetric photomap. The accuracy of this photomap will be limited, principally by the geometric fidelity of the sensor system rather than by external effects, such as relief displacement, which restrict the direct cartographic use of the conventional aerial photograph. ERST-A is not designed as a topographic mapping satellite but does have real potential' for thematic mapping particularly in areas now covered by topographic maps.

  4. Gaussian Entanglement Distribution via Satellite

    Hosseinidehaj, Nedasadat


    In this work we analyse three quantum communication schemes for the generation of Gaussian entanglement between two ground stations. Communication occurs via a satellite over two independent atmospheric fading channels dominated by turbulence-induced beam wander. In our first scheme the engineering complexity remains largely on the ground transceivers, with the satellite acting simply as a reflector. Although the channel state information of the two atmospheric channels remains unknown in this scheme, the Gaussian entanglement generation between the ground stations can still be determined. On the ground, distillation and Gaussification procedures can be applied, leading to a refined Gaussian entanglement generation rate between the ground stations. We compare the rates produced by this first scheme with two competing schemes in which quantum complexity is added to the satellite, thereby illustrating the trade-off between space-based engineering complexity and the rate of ground-station entanglement generation...

  5. Estimating Soil Moisture from Satellite Microwave Observations

    Owe, M.; VandeGriend, A. A.; deJeu, R.; deVries, J.; Seyhan, E.


    Cooperative research in microwave remote sensing between the Hydrological Sciences Branch of the NASA Goddard Space Flight Center and the Earth Sciences Faculty of the Vrije Universiteit Amsterdam began with the Botswana Water and Energy Balance Experiment and has continued through a series of highly successful International Research Programs. The collaboration between these two research institutions has resulted in significant scientific achievements, most notably in the area of satellite-based microwave remote sensing of soil moisture. The Botswana Program was the first joint research initiative between these two institutions, and provided a unique data base which included historical data sets of Scanning Multifrequency Microwave Radiometer (SN4NM) data, climate information, and extensive soil moisture measurements over several large experimental sites in southeast Botswana. These data were the basis for the development of new approaches in physically-based inverse modelling of soil moisture from satellite microwave observations. Among the results from this study were quantitative estimates of vegetation transmission properties at microwave frequencies. A single polarization modelling approach which used horizontally polarized microwave observations combined with monthly composites of Normalized Difference Vegetation Index was developed, and yielded good results. After more precise field experimentation with a ground-based radiometer system, a dual-polarization approach was subsequently developed. This new approach realized significant improvements in soil moisture estimation by satellite. Results from the Botswana study were subsequently applied to a desertification monitoring study for the country of Spain within the framework of the European Community science research programs EFEDA and RESMEDES. A dual frequency approach with only microwave data was used for this application. The Microwave Polarization Difference Index (MPDI) was calculated from 37 GHz data

  6. Nigeria's Satellite Programme Development: Prospects and Challenges

    Akinyede, Joseph

    Nigeria's desire to maximize the benefits of space technology for its sustainable development, has become a reality with the establishment of the National Space Research and Development Agency (NASRDA) in May 1999 and the approval of the national Space Policy and Programmes in July 2001. In November, 2000, the Federal Government took a bold step with the signing of an agreement with the Surrey Satellite Technology Limited (SSTL) of United Kingdom (UK) for the design, construction and launch of a medium resolution micro-satellite - NigeriaSat-1 with a Ground Sampling Distance of thirty-two (32) meters. The agreement also covers the Know-How-Technology-Training (KHTT) to Nigerian Engineers and Scientists for a period of 18th months at SSTL‘s facility in the U.K.. NigeriaSat-1 was successfully launched into Leo Earth Orbit on 27th September, 2003. NigeriaSat- 1 is one of the five (5) satellites belonging to Nigeria, Algeria, Turkey, United Kingdom and China being operated in a Disaster Monitoring Constellation (DMC). The launch of NigeriaSat-1 has promoted access to information which has become a strategy for mass socio-economic development, as information underscores all developmental effort be it in education, provision of health services, marketing, construction industry, tourism, defense, etc. As a follow-up to the successful launch of NigeriaSat-1, the government of Nigeria started the implementation of a Nigerian communication satellite (NigcomSat-1) to address the problem of communication which is the greatest drawbacks to the socio-economic development of the country, particularly in the areas of rural telephone, tele-education, tele-medicine, egovernment, e-commerce and real-time monitoring services. NigcomSat-1, which carries 40- hybrid transponders in the C, KU, KA and L bands, has a 15 years life span and coverage of the African continent, Middle East and part of Europe was launched in May 2007. To satisfy geospatial data needs in sectors such as survey

  7. Reinventing the Solar Power Satellite

    Landis, Geoffrey A.


    The selling price of electrical power varies with time. The economic viability of space solar power is maximum if the power can be sold at peak power rates, instead of baseline rate. Price and demand of electricity was examined from spot-market data from four example markets: New England, New York City, suburban New York, and California. The data was averaged to show the average price and demand for power as a function of time of day and time of year. Demand varies roughly by a factor of two between the early-morning minimum demand, and the afternoon maximum; both the amount of peak power, and the location of the peak, depends significantly on the location and the weather. The demand curves were compared to the availability curves for solar energy and for tracking and non-tracking satellite solar power systems in order to compare the market value of terrestrial and solar electrical power. In part 2, new designs for a space solar power (SSP) system were analyzed to provide electrical power to Earth for economically competitive rates. The approach was to look at innovative power architectures to more practical approaches to space solar power. A significant barrier is the initial investment required before the first power is returned. Three new concepts for solar power satellites were invented and analyzed: a solar power satellite in the Earth-Sun L2 point, a geosynchronous no-moving parts solar power satellite, and a nontracking geosynchronous solar power satellite with integral phased array. The integral-array satellite had several advantages, including an initial investment cost approximately eight times lower than the conventional design.

  8. MEMOS - Mars Environment Monitoring Satellite

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


    The Swedish Institute of Space Physics (IRF) in cooperation with the Swedish Space Corporation (SSC) has conducted first studies on a Mars Environment Monitoring Satellite (MEMOS). The MEMOS microsatellite (mass ELT) Proximity-1 transceiver will autonomously communicate with the parent satellite at inter-satellite ranges 2 kbit/s. The transceiver also implements a coherent transponding mode for orbit determination through two-way Doppler ranging between the parent satellite and MEMOS. In addition ELT is compatible with a future Martian communication and navigation network pursued by NASA, which could be taken advantage of in the future for relaying data or performing ranging via other satellites part of the network. A system design driver for inter-satellite communication at Mars is the high demand of power. This leads to a disk-shape and thus easy to accommodate spacecraft configuration of MEMOS comprising a single sun-pointing solar array favourable in terms of power and spin stability. Multi-junction solar cells, which currently have an efficiency of ~29% under laboratory conditions are a key factor to keep MEMOS solar array area of ~1.15 m2 small compared to the worst case system power requirements of ~105 W. During eclipse periods high-efficient Li-ion batteries (6 x 20 Wh) will ensure power supply. The spacecraft and payload design will incorporate new technology developments such as autonomous navigation, MicroElectroMechanical Systems MEMS, Micro- Opto-ElectroMechanical Systems MOEMS and new materials to achieve low mass at high performance. Thereby it will profit from Swedish developments and heritage in small- / microsatellites like Astrid-2, SMART-1 or the upcoming rendezvous and formation flying demonstration mission PRISMA.

  9. Communication Satellites 1958 to 1986


    effort that is still advancing the state of the art . 2-1 3. EXPERIMENTAL SATELLITES Although the performance of communication satellites could be...bandwidths was much beyond the state of the art . The choice of the Delta launch vehicle provided basic design constraints such as size, weight, and... Griego M6/215 A. S. Gilcrest M4/958 T. J. Carr M5/699 C. H. Bredall M5/690 J. B. Bryson M5/669 R. L. Porter M5/692 T. M. Bedbury M5/669 R. D. Smith

  10. Chameleon gravity and satellite geodesy

    Morris, J R


    We consider the possibility of the detection of a chameleon effect by an earth orbiting satellite such as LAGEOS, and possible constraints that might be placed on chameleon model parameters. Approximate constraints presented here result from using a simple monopole approximation for the gravitational field of the earth, along with results from the Khoury-Weltman chameleon model, solar system constraints obtained from the Cassini mission, and parameter bounds obtained from the LAGEOS satellite. It is furthermore suggested that a comparison of ground-based and space-based multipole moments of the geopotential could reveal a possible chameleon effect.

  11. The Cosmic Background Explorer Satellite

    Mather, J.; Kelsall, T.


    The Cosmic Background Explorer (COBE) satellite, planned for launch in 1985, will measure the diffuse infrared and microwave radiation of the universe over the entire wavelength range from a few microns to 1.3 cm. It will include three instruments: a set of microwave isotropy radiometers at 23, 31, 53, and 90 GHz, an interferometer spectrometer from 1 to 100/cm, and a filter photometer from 1 to 300 microns. The COBE satellite is designed to reach the sensitivity limits set by foreground sources such as the interstellar and interplanetary dust, starlight, and galactic synchrotron radiation, so that a diffuse residual radiation may be interpreted unambiguously as extragalactic

  12. Vocoders in mobile satellite communications

    Kriedte, W.; Canavesio, F.; dal Degan, N.; Pirani, G.; Rusina, F.; Usai, P.

    Owing to the power constraints that characterize onboard transmission sections, low-bit-rate coders seem suitable for speech communications inside mobile satellite systems. Vocoders that operate at rates below 4.8 kbit/s could therefore be a desirable solution for this application, providing also the redundancy that must be added to cope with the channel error rate. After reviewing the mobile-satellite-systems aspects, the paper outlines the features of two different types of vocoders that are likely to be employed, and the relevant methods of assessing their performances. Finally, some results from computer simulations of the speech transmission systems are reported.

  13. Advanced Communications Technology Satellite (ACTS)

    Olmstead, Dean A.; Schertler, Ronald J.

    The benefits that will be offered by the NASA-sponsored communication spacecraft ACTS which is scheduled for launch in 1992 are described together with examples of demonstrations on proposed data, video, and voice applications supported by the advanced ACTS technologies. Compared to existing satellite service, the ACTS will provide lower cost, better service, greater convenience, and improved service reliability of telecommunications to customers around the world. In addition, the pioneering ACTS technology will provide many capabilities qualitatively different from those of current satellite systems, such as on-demand assignment, frequency reuse, and the flexible targeting of spot beams directly to the very-small-aperture terminals at customer premises.

  14. Mobile satellite communications for consumers

    Noreen, Gary K.


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

  15. Advanced Power Technology Development Activities for Small Satellite Applications

    Piszczor, Michael F.; Landis, Geoffrey A.; Miller, Thomas B.; Taylor, Linda M.; Hernandez-Lugo, Dionne; Raffaelle, Ryne; Landi, Brian; Hubbard, Seth; Schauerman, Christopher; Ganter, Mathew; hide


    NASA Glenn Research Center (GRC) has a long history related to the development of advanced power technology for space applications. This expertise covers the breadth of energy generation (photovoltaics, thermal energy conversion, etc.), energy storage (batteries, fuel cell technology, etc.), power management and distribution, and power systems architecture and analysis. Such advanced technology is now being developed for small satellite and cubesat applications and could have a significant impact on the longevity and capabilities of these missions. A presentation during the Pre-Conference Workshop will focus on various advanced power technologies being developed and demonstrated by NASA, and their possible application within the small satellite community.

  16. Permanent GNSS Observations at Agh-Ust Satellite Observatory

    Kudrys, Jacek


    GPS satellite observations at the Faculty of Mining Surveying and Environmental Engineering AGH-UST are conducted since the early 90s of the last century. In 2001, efforts have been made on getting permanently functioning GPS station. At present, observatory is EPN operational center for two GNSS stations KRAW and KRA1. Moreover, KRA1 station is one of fundamental control points in polish horizontal network. The article gives the history and scope of the research carried out in the satellite observatory AGH-UST during the period 2001 - 2015.

  17. Broadcast satellite service: The international dimension

    Samara, Noah


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

  18. Advances Made in the Next Generation of Satellite Networks

    Bhasin, Kul B.


    Because of the unique networking characteristics of communications satellites, global satellite networks are moving to the forefront in enhancing national and global information infrastructures. Simultaneously, broadband data services, which are emerging as the major market driver for future satellite and terrestrial networks, are being widely acknowledged as the foundation for an efficient global information infrastructure. In the past 2 years, various task forces and working groups around the globe have identified pivotal topics and key issues to address if we are to realize such networks in a timely fashion. In response, industry, government, and academia undertook efforts to address these topics and issues. A workshop was organized to provide a forum to assess the current state-of-the-art, identify key issues, and highlight the emerging trends in the next-generation architectures, data protocol development, communication interoperability, and applications. The Satellite Networks: Architectures, Applications, and Technologies Workshop was hosted by the Space Communication Program at the NASA Lewis Research Center in Cleveland, Ohio. Nearly 300 executives and technical experts from academia, industry, and government, representing the United States and eight other countries, attended the event (June 2 to 4, 1998). The program included seven panels and invited sessions and nine breakout sessions in which 42 speakers presented on technical topics. The proceedings covers a wide range of topics: access technology and protocols, architectures and network simulations, asynchronous transfer mode (ATM) over satellite networks, Internet over satellite networks, interoperability experiments and applications, multicasting, NASA interoperability experiment programs, NASA mission applications, and Transmission Control Protocol/Internet Protocol (TCP/IP) over satellite: issues, relevance, and experience.

  19. 一种高动态环境下卫星扩频信号的快速捕获方法研究%Research on Quickly Acquisition Method About High Dynamic Satellite Navigation Signals

    张现宇; 郭熙业; 王跃科; 唐银银


    In the present satellite navigation applications , the global navigation satellite system ( GNSS) receiver must be able to work well at large dynamic environment .In order to capture rapidly satellite navigation signals at the large frequency deviation , this paper presents an improved Bi-Frequency domain calculation method which could parallel search code phase and Doppler shift .First, long correla-tion integral operation is divided into short correlation integration operation with double block zeros pad-ding ( DBZP) algorithm, quickly searching code phase with circular correlation combined with Fast Fou-rier Transform ( FFT) , significantly reducing the amount of computation .Then the amount of computation is largely reduced with equivalence principle of the frequency domain circular shift and time domain carri -er peeling .Compared with continuous acquisition algorithms and single frequency domain acquisition al -gorithm under the same acquisition sensitivity conditions , operation time reduces 90%.It is suitable for rapid acquisition of GPS signals under large deviation conditions .Experiments show that the method can capture GPS signal ±500kHz within 0.1s.%现代卫星导航及测控应用对接收机在高动态环境下实现测量通信提出了迫切需求。为了解决大多普勒频偏扩频信号的快速捕获问题,提出了一种在频域并行搜索码相位及多普勒频偏的双频域快速捕获方法。采用双块补零算法将长的相关积分操作分割为多个短的相关积分操作,然后采用快速傅里叶变换进行圆周相关,大大节约了处理时间,利用频域圆周移位与时域载波剥离等价的原理,大幅提高了频率搜索效率。与时域相关算法和单频域计算方法相比,在捕获灵敏度不变的条件下,该方法将计算量减少90%,显著提高了运算速度,适合高动态环境下扩频信号的快速捕获。该方案应用于星载接收机平台FPGA实现,测试

  20. Role of Satellite Sensors in Groundwater Exploration

    Saumitra Mukherjee


    Full Text Available Spatial as well as spectral resolution has a very important role to play in water resource management. It was a challenge to explore the groundwater and rainwater harvesting sites in the Aravalli Quartzite-Granite-Pegmatite Precambrian terrain of Delhi, India. Use of only panchromatic sensor data of IRS-1D satellite with 5.8-meter spatial resolution has the potential to infer lineaments and faults in this hard rock area. It is essential to identify the location of interconnected lineaments below buried pediment plains in the hard rock area for targeting sub-surface water resources. Linear Image Self Scanning sensor data of the same satellite with 23.5-meter resolution when merged with the panchromatic data has produced very good results in delineation of interconnected lineaments over buried pediment plains as vegetation anomaly. These specific locations of vegetation anomaly were detected as dark red patches in various hard rock areas of Delhi. Field investigation was carried out on these patches by resistivity and magnetic survey in parts of Jawaharlal Nehru University (JNU, Indira Gandhi national Open University, Research and Referral Hospital and Humayuns Tomb areas. Drilling was carried out in four locations of JNU that proved to be the most potential site with ground water discharge ranging from 20,000 to 30,000 liters per hour with 2 to 4 meters draw down. Further the impact of urbanization on groundwater recharging in the terrain was studied by generating Normalized difference Vegetation Index (NDVI map which was possible to generate by using the LISS-III sensor of IRS-1D satellite. Selection of suitable sensors has definitely a cutting edge on natural resource exploration and management including groundwater.

  1. Program on application of communications satellites to educational development

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


    Interdisciplinary research in needs analysis, communications technology studies, and systems synthesis is reported. Existing and planned educational telecommunications services are studied and library utilization of telecommunications is described. Preliminary estimates are presented of ranges of utilization of educational telecommunications services for 1975 and 1985; instructional and public television, computer-aided instruction, computing resources, and information resource sharing for various educational levels and purposes. Communications technology studies include transmission schemes for still-picture television, use of Gunn effect devices, and TV receiver front ends for direct satellite reception at 12 GHz. Two major studies in the systems synthesis project concern (1) organizational and administrative aspects of a large-scale instructional satellite system to be used with schools and (2) an analysis of future development of instructional television, with emphasis on the use of video tape recorders and cable television. A communications satellite system synthesis program developed for NASA is now operational on the university IBM 360-50 computer.

  2. Satellite Sounder Data Assimilation for Improving Alaska Region Weather Forecast

    Zhu, Jiang; Stevens, E.; Zavodsky, B. T.; Zhang, X.; Heinrichs, T.; Broderson, D.


    Data assimilation has been demonstrated very useful in improving both global and regional numerical weather prediction. Alaska has very coarser surface observation sites. On the other hand, it gets much more satellite overpass than lower 48 states. How to utilize satellite data to improve numerical prediction is one of hot topics among weather forecast community in Alaska. The Geographic Information Network of Alaska (GINA) at University of Alaska is conducting study on satellite data assimilation for WRF model. AIRS/CRIS sounder profile data are used to assimilate the initial condition for the customized regional WRF model (GINA-WRF model). Normalized standard deviation, RMSE, and correlation statistic analysis methods are applied to analyze one case of 48 hours forecasts and one month of 24-hour forecasts in order to evaluate the improvement of regional numerical model from Data assimilation. The final goal of the research is to provide improved real-time short-time forecast for Alaska regions.

  3. Approximate Approaches to Geometric Corrections of High Resolution Satellite Imagery

    SHI Wenzhong; Ahmed Shaker


    The exploitation of different non-rigorous mathematical models as opposed to the satellite rigorous models is discussed for geometric corrections and topographic/thematic maps production of high-resolution satellite imagery (HRSI). Furthermore, this paper focuses on the effects of the number of GCPs and the terrain elevation difference within the area covered by the images on the obtained ground points accuracy. From the research, it is obviously found that non-rigorous orientation and triangulation models can be used successfully in most cases for 2D rectification and 3D ground points determination without a camera model or the satellite ephemeris data. In addition, the accuracy up to the sub-pixel level in plane and about one pixel in elevation can be achieved with a modest number of GCPs.

  4. Two-Channel Satellite Retrievals of Aerosol Properties: An Overview

    Mishchenko, Michael I.


    In order to reduce current uncertainties in the evaluation of the direct and indirect effects of tropospheric aerosols on climate on the global scale, it has been suggested to apply multi-channel retrieval algorithms to the full period of existing satellite data. This talk will outline the methodology of interpreting two-channel satellite radiance data over the ocean and describe a detailed analysis of the sensitivity of retrieved aerosol parameters to the assumptions made in different retrieval algorithms. We will specifically address the calibration and cloud screening issues, consider the suitability of existing satellite data sets to detecting short- and long-term regional and global changes, compare preliminary results obtained by several research groups, and discuss the prospects of creating an advanced retroactive climatology of aerosol optical thickness and size over the oceans.

  5. Next Generation Solar Array Technologies for Small Satellites

    Fosness, E.; Guerrero, J.; Mayberry, C.; Carpenter, B.; Goldstein, D.


    Recent advances in Shape Memory Alloy (SMA), Elastic Memory Composites (EMC), and ultra- light composites along with thin-film Copper-Indium- Diselinide (CIS) photovoltaics have offered the potential to provide solar array systems for small satellites that are significantly lighter than the current state of the practice. The Air Force Research Laboratory (AFRL), National Aeronautics and Space Administration (NASA) Langley, Defense Advanced Research Projects Agency (DARPA), and Lockheed Martin...

  6. Application and Research of PID Algorithm in Shipborne Satellite Communications System%船载卫星通信系统中PID算法的应用与探究



    In shipborne satellite communications system,how to use azimuth,pitch,roll angle error value of DC motors to adjust the an-tenna stance in order to achieve real-time antenna pointing stability is the most important problem. The algorithm of DC motors’ control will directly affect the work performance of the communication system,so the study of its control algorithm becomes very important. PID algorithm is simple,adaptable and robust,which is very suitable for shipborne satellite communications system. However,the PID algo-rithm is prone to integration saturation and weak immunity situation. Based on the above-described problems,propose some improved al-gorithms,including integral separation,integral limit,incomplete integration and incomplete differential. The improved algorithms can not only prevent too much overshoot,but also accelerate response speed,improving control accuracy and immunity performance.%在船载卫星通信系统中,最重要的问题就是利用方位、俯仰、横摇的角度误差值控制直流电机实时调整天线姿态,使天线波束中心始终准确地对准卫星。直流电机控制算法的优劣将直接影响到船载卫星通信系统的工作性能,因此对船载卫星通信系统中控制算法的研究就显得非常重要。 PID算法原理简单,适应性强,鲁棒性好,非常适合应用于船载卫星通信系统;但它也容易出现积分饱和、抗干扰性差的问题。文中基于上述问题,提出积分分离、积分限幅、不完全积分和不完全微分的改进型PID算法,它不但可以防止产生太大超调,而且加快了响应速度,提高了控制精度和抗干扰能力。


    高云峰; 宝音贺西; 李俊峰


    Recently, the research of dynamics and control of the satellite formation flying has been attracting a great deal of attentions of the researchers. The theory of the research was mainly based on Clohessy-Wiltshire's (C-W's) equations, which describe the relative motion between two satellites. But according to some special examples and qualitative analysis, neither the initial parameters nor the period of the solution of C-W' s equations accord with the actual situation, and the conservation of energy is no longer held. A new method developed from orbital element description of single satellite, named relative orbital element method ( ROEM), was introduced. This new method, with clear physics conception and wide application range, overcomes the limitation of C-W's equation, and the perio dic solution is a natural conclusion. The simplified equation of the relative motion is obtained when the eccentricity of the main satellite is small. Finally,the results of the two methods ( C-W' s equation and ROEM) are compared and the limitations of C-W' s equations are pointed out and explained.

  8. An interactive system for compositing digital radar and satellite data

    Heymsfield, G. M.; Ghosh, K. K.; Chen, L. C.


    This paper describes an approach for compositing digital radar data and GOES satellite data for meteorological analysis. The processing is performed on a user-oriented image processing system, and is designed to be used in the research mode. It has a capability to construct PPIs and three-dimensional CAPPIs using conventional as well as Doppler data, and to composite other types of data. In the remapping of radar data to satellite coordinates, two steps are necessary. First, PPI or CAPPI images are remapped onto a latitude-longitude projection. Then, the radar data are projected into satellite coordinates. The exact spherical trigonometric equations, and the approximations derived for simplifying the computations are given. The use of these approximations appears justified for most meteorological applications. The largest errors in the remapping procedure result from the satellite viewing angle parallax, which varies according to the cloud top height. The horizontal positional error due to this is of the order of the error in the assumed cloud height in mid-latitudes. Examples of PPI and CAPPI data composited with satellite data are given for Hurricane Frederic on 13 September 1979 and for a squall line on 2 May 1979 in Oklahoma.

  9. Geospatial Visualization of Global Satellite Images with Vis-EROS

    Standart, G. D.; Stulken, K. R.; Zhang, Xuesong; Zong, Ziliang


    The Earth Resources Observation and Science (EROS) Center of U.S. Geological Survey is currently managing and maintaining the world largest satellite images distribution system, which provides 24/7 free download service for researchers all over the globe in many areas such as Geology, Hydrology, Climate Modeling, and Earth Sciences. A large amount of geospatial data contained in satellite images maintained by EROS is generated every day. However, this data is not well utilized due to the lack of efficient data visualization tools. This software implements a method for visualizing various characteristics of the global satellite image download requests. More specifically, Keyhole Markup Language (KML) files are generated which can be loaded into an earth browser such as Google Earth. Colored rectangles associated with stored satellite scenes are painted onto the earth browser; and the color and opacity of each rectangle is varied as a function of the popularity of the corresponding satellite image. An analysis of the geospatial information obtained relative to specified time constraints provides an ability to relate image download requests to environmental, political, and social events.

  10. Discovery of Remote Globular Cluster Satellites of M87

    Sparkman, Lea; Guo, Rachel; Toloba, Elisa; Guhathakurta, Puragra; Peng, Eric W.; Ferrarese, Laura; Cote, Patrick; NGVS Collaboration


    We present the discovery of several tens of globular clusters (GCs) in the outer regions of the giant elliptical M87, the brightest galaxy in the Virgo Cluster. These M87 GC satellites were discovered in the course of Keck/DEIMOS spectroscopic follow up of GC candidates that were identified in the Next Generation Virgo cluster Survey (NGVS). Specifically, the primary targets of this Keck spectroscopic campaign were GC satellites of early-type dwarf (dE) galaxies. However, we found that our sample contained a subset of GCs for which M87 is the most likely host. This subset is consistent with having an r^-1 power-law surface density distribution and a radial velocity distribution both centered on M87. The remote M87 GC satellites span the radial range 140 to 900 kpc, out to about a third of the Virgo Cluster's virial radius (for comparison, M87's effective radius is only 8 kpc). These M87 GC satellites are probably former satellites of other Virgo Cluster galaxies that have subsequently been cannibalized by M87.This research was supported by the National Science Foundation and the UC Santa Cruz Science Internship Program.

  11. Muscle Satellite Cells: Exploring the Basic Biology to Rule Them.

    Almeida, Camila F; Fernandes, Stephanie A; Ribeiro Junior, Antonio F; Keith Okamoto, Oswaldo; Vainzof, Mariz


    Adult skeletal muscle is a postmitotic tissue with an enormous capacity to regenerate upon injury. This is accomplished by resident stem cells, named satellite cells, which were identified more than 50 years ago. Since their discovery, many researchers have been concentrating efforts to answer questions about their origin and role in muscle development, the way they contribute to muscle regeneration, and their potential to cell-based therapies. Satellite cells are maintained in a quiescent state and upon requirement are activated, proliferating, and fusing with other cells to form or repair myofibers. In addition, they are able to self-renew and replenish the stem pool. Every phase of satellite cell activity is highly regulated and orchestrated by many molecules and signaling pathways; the elucidation of players and mechanisms involved in satellite cell biology is of extreme importance, being the first step to expose the crucial points that could be modulated to extract the optimal response from these cells in therapeutic strategies. Here, we review the basic aspects about satellite cells biology and briefly discuss recent findings about therapeutic attempts, trying to raise questions about how basic biology could provide a solid scaffold to more successful use of these cells in clinics.

  12. Aeronautical satellite antenna steering using magnetic field sensors

    Sydor, John; Dufour, Martial


    Designers of aeronautical satellite terminals are often faced with the problem of steering a directive antenna from an airplane or helicopter. This problem is usually solved by using aircraft orientation information derived from inertial sensors on-board the aircraft in combination with satellite ephemeris information calculated from geographic coordinates. This procedure works well but relies heavily on avionics that are external to the terminal. For the majority of small aircraft and helicopters which will form the bulk of future aeronautical satcom users, such avionics either do not exist or are difficult for the satellite terminal to interface with. At the Communications Research Center (CRC), work has been undertaken to develop techniques that use the geomagnetic field and satellite antenna pointing vectors (both of which are stationary in a local geographical area) to track the position of a satellite relative to a moving platform such as an aircraft. The performance of this technique is examined and a mathematical steering transformation is developed within this paper. Details are given regarding the experimental program that will be undertaken to test the concepts proposed herein.

  13. China's Meteorological Satellite Application System

    Zhang Jiashen


    @@ (Continued) Applications In Global Environment And Natural Disaster Monitoring 1) Application in world crop yield estimation China is now one of the few nations in the world that can provide operational service with both GEO and polar-orbit meteorological satellites.

  14. Water Quality Monitoring by Satellite

    Journal of Chemical Education, 2004


    The availability of abundant water resources in the Upper Midwest of the United States is nullified by their contamination through heavy commercial and industrial activities. Scientists have taken the responsibility of detecting the water quality of these resources through remote-sensing satellites to develop a wide-ranging water purification plan…

  15. Introductory Course on Satellite Navigation

    Giger, Kaspar; Knogl, J. Sebastian


    Satellite navigation is widely used for personal navigation and more and more in precise and safety-critical applications. Thus, the subject is suited for attracting the interest of young people in science and engineering. The practical applications allow catching the students' attention for the theoretical background. Educational material on the…

  16. Satellite imager calibration and validation

    Vhengani, L


    Full Text Available The success or failure of any earth observation mission depends on the quality of its data. Data quality is assessed by determining the radiometric, spatial, spectral and geometric fidelity of the satellite sensor. The process is termed calval...

  17. GOES-R: Satellite Insight

    Fitzpatrick, Austin J.; Leon, Nancy J.; Novati, Alexander; Lincoln, Laura K.; Fisher, Diane K.


    GOES-R: Satellite Insight seeks to bring awareness of the GOES-R (Geostationary Operational Environmental Satellite -- R Series) satellite currently in development to an audience of all ages on the emerging medium of mobile games. The iPhone app (Satellite Insight) was created for the GOES-R Program. The app describes in simple terms the types of data products that can be produced from GOES-R measurements. The game is easy to learn, yet challenging for all audiences. It includes educational content and a path to further information about GOESR, its technology, and the benefits of the data it collects. The game features action-puzzle game play in which the player must prevent an overflow of data by matching falling blocks that represent different types of GOES-R data. The game adds more different types of data blocks over time, as long as the player can prevent a data overflow condition. Points are awarded for matches, and players can compete with themselves to beat their highest score.

  18. The Omninet mobile satellite system

    Salmasi, A.; Curry, W.

    Mobile Satellite System (MSS) design offering relatively low cost voice, data, and position location services to nonmetropolitan areas of North America is proposed. The system provides spectrally efficient multiple access and modulation techniques, and flexible user interconnection to public and private switched networks. Separate UHF and L-band satellites employing two 9.1 m unfurlable antennas each, achieve a 6048 channel capacity and utilize spot beams. Mobile terminals have modular design and employ 5 dBi omnidirectional antennas. Gateway stations (with two 5 m Ku-band antennas) and base stations (with a single 1.8 m Ku-band antenna) transmit terrestrial traffic to the satellite, where traffic is then transponded via an L-band or UHF downlink to mobile users. The Network Management Center uses two 5-m antennas and incorporates the Integrated-Adaptive Mobile Access Protocol to assure demand assignment of satellite capacity. Preliminary implementation of this low-risk system involves a mobile alphanumeric data service employing receive-only terminals at Ku-band projected for 1987, and plans for the launching of L-band receive-only packages as early as 1988.

  19. Platelet satellitism in infectious disease?

    Laskaj, Renata; Sikiric, Dubravka; Skerk, Visnja


    Background Platelet satellitism is a phenomenon of unknown etiology of aggregating platelets around polymorphonuclear neutrophils and other blood cells which causes pseudothrombocytopenia, visible by microscopic examination of blood smears. It has been observed so far in about a hundred cases in the world. Case subject and methods Our case involves a 73-year-old female patient with a urinary infection. Biochemical serum analysis (CRP, glucose, AST, ALT, ALP, GGT, bilirubin, sodium, potassium, chloride, urea, creatinine) and blood cell count were performed with standard methods on autoanalyzers. Serum protein fractions were examined by electrophoresis and urinalysis with standard methods on autoanalyzer together with microscopic examination of urine sediment. Erythrocyte sedimentation rate, blood culture and urine culture tests were performed with standard methods. Results Due to typical pathological values for bacterial urinary infection, the patient was admitted to the hospital. Blood smear examination revealed phenomenon, which has persisted for three weeks after the disease has been cured. Blood smears with EDTA as an anticoagulant had platelet satellitism whereas the phenomenon was not observed in tubes with different anticoagulants (Na, Li-heparin) and capillary blood. Discussion We hypothesize that satellitism was induced by some immunological mechanism through formation of antibodies which have mediated platelets binding to neutrophil membranes and vice versa. Unfortunately we were unable to determine the putative trigger for this phenomenon. To our knowledge this is the second case of platelet satellitism ever described in Croatia. PMID:26110042

  20. China Satcom: Innovating Satellite Communication


    China Satellite Communications Group Corporation (China Satcom) is a state-owned large-sized key enterprise formally established on Dec. 19, 2001 according to the general deployment of the State Council on telecommunication system reform. Relying on its complete service system, China Satcom provides various users with specialized and high quality information communication service.