Analysis of data collected by the Tatyana II satellite

International Nuclear Information System (INIS)

Rivera, Lilianaa; Mendoza-Torres, Eduardo; Martinez, Oscar; Salazar, Humberto

2011-01-01

The Tatyana II satellite is the second one of the University Satellite Program, which is led by the Moscow State University with the participation of the Benemerita Universidad Autonoma de Puebla. This satellite has ultraviolet, red-infrared and charged particles detectors. In this work preliminary results based on the data collected by these detectors on board the satellite over a period of ∼3.5 months are presented.

47 CFR 76.1507 - Competitive access to satellite cable programming.

Science.gov (United States)

2010-10-01

... programming. 76.1507 Section 76.1507 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST... access to satellite cable programming. (a) Any provision that applies to a cable operator under §§ 76... provides video programming on its open video system, except as limited by paragraph (a) (1)-(3) of this...

An overview of the Nuclear Electric Propulsion Space Test Program (NEPSTP) satellite

International Nuclear Information System (INIS)

Voss, S.S.; Reynolds, E.L.

1994-01-01

Early in 1992 the idea of purchasing a Russian designed and fabricated space reactor power system and integrating it with a US designed satellite went from fiction to reality with the purchase of the first two Topaz II reactors by the Strategic Defense Initiative Organization (now the Ballistic Missile Defense Organization (BMDO)). The New Mexico Alliance was formed to establish a ground test facility in which to perform nonnuclear systems testing of the Topaz II, and to evaluate the Topaz II system for flight testing with respect to safety, performance, and operability. In conjunction, SDIO requested that the Applied Physics Laboratory in Laurel, MD propose a mission and design a satellite in which the Topaz II could be used as the power source. The outcome of these two activities was the design of the Nuclear Electric Propulsion Space Test Program (NEPSTP) satellite which combines a modified Russian Topaz II power system with a US designed satellite to achieve a specified mission. Due to funding reduction within the SDIO, the Topaz II flight program was postponed indefinitely at the end of Fiscal year 1993. The purpose of this paper is to present an overview of the NEPSTP mission and the satellite design at the time the flight program ended

ESPACE - a geodetic Master's program for the education of Satellite Application Engineers

Science.gov (United States)

Hedman, K.; Kirschner, S.; Seitz, F.

2012-04-01

In the last decades there has been a rapid development of new geodetic and other Earth observation satellites. Applications of these satellites such as car navigation systems, weather predictions, and, digital maps (such as Google Earth or Google Maps) play a more and more important role in our daily life. For geosciences, satellite applications such as remote sensing and precise positioning/navigation have turned out to be extremely useful and are meanwhile indispensable. Today, researchers within geodesy, climatology, oceanography, meteorology as well as within Earth system science are all dependent on up-to-date satellite data. Design, development and handling of these missions require experts with knowledge not only in space engineering, but also in the specific applications. That gives rise to a new kind of engineers - satellite application engineers. The study program for these engineers combines parts of different classical disciplines such as geodesy, aerospace engineering or electronic engineering. The satellite application engineering program Earth Oriented Space Science and Technology (ESPACE) was founded in 2005 at the Technische Universität München, mainly from institutions involved in geodesy and aerospace engineering. It is an international, interdisciplinary Master's program, and is open to students with a BSc in both Science (e.g. Geodesy, Mathematics, Informatics, Geophysics) and Engineering (e.g. Aerospace, Electronical and Mechanical Engineering). The program is completely conducted in English. ESPACE benefits from and utilizes its location in Munich with its unique concentration of expertise related to space science and technology. Teaching staff from 3 universities (Technische Universität München, Ludwig-Maximilian University, University of the Federal Armed Forces), research institutions (such as the German Aerospace Center, DLR and the German Geodetic Research Institute, DGFI) and space industry (such as EADS or Kayser-Threde) are

National Oceanic and Atmospheric Administration: National Weather Service Modernization and Weather Satellite Program

National Research Council Canada - National Science Library

Willemssen, Joel

2000-01-01

...). At your request, we will discuss the status of the National Weather Service (NWS) systems modernization and the National Environmental Satellite, Data, and Information Service's Geostationary Operational Environmental Satellite (GOES) program...

Scripting Module for the Satellite Orbit Analysis Program (SOAP)

Science.gov (United States)

Carnright, Robert; Paget, Jim; Coggi, John; Stodden, David

2008-01-01

This add-on module to the SOAP software can perform changes to simulation objects based on the occurrence of specific conditions. This allows the software to encompass simulation response of scheduled or physical events. Users can manipulate objects in the simulation environment under programmatic control. Inputs to the scripting module are Actions, Conditions, and the Script. Actions are arbitrary modifications to constructs such as Platform Objects (i.e. satellites), Sensor Objects (representing instruments or communication links), or Analysis Objects (user-defined logical or numeric variables). Examples of actions include changes to a satellite orbit ( v), changing a sensor-pointing direction, and the manipulation of a numerical expression. Conditions represent the circumstances under which Actions are performed and can be couched in If-Then-Else logic, like performing v at specific times or adding to the spacecraft power only when it is being illuminated by the Sun. The SOAP script represents the entire set of conditions being considered over a specific time interval. The output of the scripting module is a series of events, which are changes to objects at specific times. As the SOAP simulation clock runs forward, the scheduled events are performed. If the user sets the clock back in time, the events within that interval are automatically undone. This script offers an interface for defining scripts where the user does not have to remember the vocabulary of various keywords. Actions can be captured by employing the same user interface that is used to define the objects themselves. Conditions can be set to invoke Actions by selecting them from pull-down lists. Users define the script by selecting from the pool of defined conditions. Many space systems have to react to arbitrary events that can occur from scheduling or from the environment. For example, an instrument may cease to draw power when the area that it is tasked to observe is not in view. The contingency

Quad-Tree Visual-Calculus Analysis of Satellite Coverage

Science.gov (United States)

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

2003-01-01

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

Small-Body Extensions for the Satellite Orbit Analysis Program (SOAP)

Science.gov (United States)

Carnright, Robert; Stodden, David; Coggi, John

2008-01-01

An extension to the SOAP software allows users to work with tri-axial ellipsoid-based representations of planetary bodies, primarily for working with small, natural satellites, asteroids, and comets. SOAP is a widely used tool for the visualization and analysis of space missions. The small body extension provides the same visualization and analysis constructs for use with small bodies. These constructs allow the user to characterize satellite path and instrument cover information for small bodies in both 3D display and numerical output formats. Tri-axial ellipsoids are geometric shapes the diameters of which are different in each of three principal x, y, and z dimensions. This construct provides a better approximation than using spheres or oblate spheroids (ellipsoids comprising two common equatorial diameters as a distinct polar diameter). However, the tri-axial ellipsoid is considerably more difficult to work with from a modeling perspective. In addition, the SOAP small-body extensions allow the user to actually employ a plate model for highly irregular surfaces. Both tri-axial ellipsoids and plate models can be assigned to coordinate frames, thus allowing for the modeling of arbitrary changes to body orientation. A variety of features have been extended to support tri-axial ellipsoids, including the computation and display of the spacecraft sub-orbital point, ground trace, instrument footprints, and swathes. Displays of 3D instrument volumes can be shown interacting with the ellipsoids. Longitude/latitude grids, contour plots, and texture maps can be displayed on the ellipsoids using a variety of projections. The distance along an arbitrary line of sight can be computed between the spacecraft and the ellipsoid, and the coordinates of that intersection can be plotted as a function of time. The small-body extension supports the same visual and analytical constructs that are supported for spheres and oblate spheroids in SOAP making the implementation of the more

Grand Challenges in Space Technology: Distributed Satellite Systems

National Research Council Canada - National Science Library

Miller, David

2001-01-01

The MITIAFRL Distributed Satellite Systems program examines the motivation, analysis and development of technology associated with the distribution of assets and functionality over a number of cooperating satellites...

Evaluation of spacecraft technology programs (effects on communication satellite business ventures), volume 2

Science.gov (United States)

Greenburg, J. S.; Kaplan, M.; Fishman, J.; Hopkins, C.

1985-01-01

The computational procedures used in the evaluation of spacecraft technology programs that impact upon commercial communication satellite operations are discussed. Computer programs and data bases are described.

Technology programs and related policies - Impacts on communications satellite business ventures

Science.gov (United States)

Greenberg, J. S.

1985-01-01

The DOMSAT II stochastic communication satellite business venture financial planning simulation model is described. The specification of business scenarios and the results of several analyses are presented. In particular, the impacts of NASA on-orbit propulsion and power technology programs are described. The effects of insurance rates and self-insurance and of the use of the Space Shuttle and Ariane transportation systems on a typical fixed satellite service business venture are discussed.

Commercial Satellite Imagery Analysis for Countering Nuclear Proliferation

Science.gov (United States)

Albright, David; Burkhard, Sarah; Lach, Allison

2018-05-01

High-resolution commercial satellite imagery from a growing number of private satellite companies allows nongovernmental analysts to better understand secret or opaque nuclear programs of countries in unstable or tense regions, called proliferant states. They include North Korea, Iran, India, Pakistan, and Israel. By using imagery to make these countries’ aims and capabilities more transparent, nongovernmental groups like the Institute for Science and International Security have affected the policies of governments and the course of public debate. Satellite imagery work has also strengthened the efforts of the International Atomic Energy Agency, thereby helping this key international agency build its case to mount inspections of suspect sites and activities. This work has improved assessments of the nuclear capabilities of proliferant states. Several case studies provide insight into the use of commercial satellite imagery as a key tool to educate policy makers and affect policy.

Environmental assessment for the satellite power system concept development and evaluation program: atmospheric effects

International Nuclear Information System (INIS)

Rote, D.M.; Brubaker, K.L.; Lee, J.L.

1980-11-01

The US Department of Energy (DOE) has undertaken a preliminary, three-year program to investigate the impacts of the construction and operation of a satellite power system, of unprecedented scale. The Department of Energy's program, titled The Concept Development and Evaluation Program, focused its investigations on a Reference System description that calls for the use of either silicon (Si) or gallium aluminum-arsenide (GaAlAs) photovoltaic cells on 60 satellites to be constructed in GEO over a 30-yr period. Rectennas would be constructed on the ground to receive microwave energy from the satellites. Each satellite-rectenna pair is designed to produce 5 GW of power on an essentially continuous basis for use as a baseload power source for an electric power distribution system. The environmental assessment part of the program was divided into five interdependent task areas. The present document constitutes the final technical report on one of the five task areas, the Assessment of the Atmospheric Effects, and as such presents an in-depth summary of work performed during the assessment program. The issues associated with SPS activities in the troposphere are examined. These include tropospheric weather modification related to rectenna operations and rocket launches, and air quality impacts related to rocketlaunch ground clouds. Then progressing upward through the various levels of the atmosphere, the principal middle and upper atmospheric effects associated with rocket effluents are analyzed. Finally, all of the potential SPS atmospheric effects are summarized

Trajectory Planning of Satellite Formation Flying using Nonlinear Programming and Collocation

Directory of Open Access Journals (Sweden)

Hyung-Chu Lim

2008-12-01

Full Text Available Recently, satellite formation flying has been a topic of significant research interest in aerospace society because it provides potential benefits compared to a large spacecraft. Some techniques have been proposed to design optimal formation trajectories minimizing fuel consumption in the process of formation configuration or reconfiguration. In this study, a method is introduced to build fuel-optimal trajectories minimizing a cost function that combines the total fuel consumption of all satellites and assignment of fuel consumption rate for each satellite. This approach is based on collocation and nonlinear programming to solve constraints for collision avoidance and the final configuration. New constraints of nonlinear equality or inequality are derived for final configuration, and nonlinear inequality constraints are established for collision avoidance. The final configuration constraints are that three or more satellites should form a projected circular orbit and make an equilateral polygon in the horizontal plane. Example scenarios, including these constraints and the cost function, are simulated by the method to generate optimal trajectories for the formation configuration and reconfiguration of multiple satellites.

Scientific analysis of satellite ranging data

Science.gov (United States)

Smith, David E.

1994-01-01

A network of satellite laser ranging (SLR) tracking systems with continuously improving accuracies is challenging the modelling capabilities of analysts worldwide. Various data analysis techniques have yielded many advances in the development of orbit, instrument and Earth models. The direct measurement of the distance to the satellite provided by the laser ranges has given us a simple metric which links the results obtained by diverse approaches. Different groups have used SLR data, often in combination with observations from other space geodetic techniques, to improve models of the static geopotential, the solid Earth, ocean tides, and atmospheric drag models for low Earth satellites. Radiation pressure models and other non-conservative forces for satellite orbits above the atmosphere have been developed to exploit the full accuracy of the latest SLR instruments. SLR is the baseline tracking system for the altimeter missions TOPEX/Poseidon, and ERS-1 and will play an important role in providing the reference frame for locating the geocentric position of the ocean surface, in providing an unchanging range standard for altimeter calibration, and for improving the geoid models to separate gravitational from ocean circulation signals seen in the sea surface. However, even with the many improvements in the models used to support the orbital analysis of laser observations, there remain systematic effects which limit the full exploitation of SLR accuracy today.

Satellite switched FDMA advanced communication technology satellite program

Science.gov (United States)

Atwood, S.; Higton, G. H.; Wood, K.; Kline, A.; Furiga, A.; Rausch, M.; Jan, Y.

1982-01-01

The satellite switched frequency division multiple access system provided a detailed system architecture that supports a point to point communication system for long haul voice, video and data traffic between small Earth terminals at Ka band frequencies at 30/20 GHz. A detailed system design is presented for the space segment, small terminal/trunking segment at network control segment for domestic traffic model A or B, each totaling 3.8 Gb/s of small terminal traffic and 6.2 Gb/s trunk traffic. The small terminal traffic (3.8 Gb/s) is emphasized, for the satellite router portion of the system design, which is a composite of thousands of Earth stations with digital traffic ranging from a single 32 Kb/s CVSD voice channel to thousands of channels containing voice, video and data with a data rate as high as 33 Mb/s. The system design concept presented, effectively optimizes a unique frequency and channelization plan for both traffic models A and B with minimum reorganization of the satellite payload transponder subsystem hardware design. The unique zoning concept allows multiple beam antennas while maximizing multiple carrier frequency reuse. Detailed hardware design estimates for an FDMA router (part of the satellite transponder subsystem) indicate a weight and dc power budget of 353 lbs, 195 watts for traffic model A and 498 lbs, 244 watts for traffic model B.

International Coordination of and Contributions to Environmental Satellite Programs.

Science.gov (United States)

1985-06-01

the international coordination of, and contributions to, environmental satellite programs. It re- views the background and history of international...Earth’s atmos- phere, surface temperature, cloud cover, water-ice boundaries, * and proton and electron flux near the Earth. They have the capability of...Islands Madagascar Sweden Chile Malaysia Switzerland China, People’s Rep. of Mali Syria Colombia Malta Tahiti Costa Rica Martinique Taiwan Curacao

An evaluation of the use of ERTS-1 satellite imagery for grizzly bear habitat analysis

Science.gov (United States)

Varney, J. R.; Craighead, J. J.; Sumner, J.

1973-01-01

Multispectral scanner images taken by the ERTS-1 satellite in August and October, 1972, were examined to determine if they would be useful in identifying and mapping favorable habitat for grizzly bears. It was possible to identify areas having a suitable mixture of alpine meadow and timber, and to eliminate those which did not meet the isolation requirements of grizzlies because of farming or grazing activity. High altitude timbered areas mapped from satellite imagery agreed reasonably well with the distribution of whitebark pine, an important food species. Analysis of satellite imagery appears to be a valuable supplement to present ground observation methods, since it allows the most important areas to be identified for intensive study and many others to be eliminated from consideration. A sampling plan can be developed from such data which will minimize field effort and overall program cost.

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

Science.gov (United States)

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

2016-12-01

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

Beyond reliability, multi-state failure analysis of satellite subsystems: A statistical approach

International Nuclear Information System (INIS)

Castet, Jean-Francois; Saleh, Joseph H.

2010-01-01

Reliability is widely recognized as a critical design attribute for space systems. In recent articles, we conducted nonparametric analyses and Weibull fits of satellite and satellite subsystems reliability for 1584 Earth-orbiting satellites launched between January 1990 and October 2008. In this paper, we extend our investigation of failures of satellites and satellite subsystems beyond the binary concept of reliability to the analysis of their anomalies and multi-state failures. In reliability analysis, the system or subsystem under study is considered to be either in an operational or failed state; multi-state failure analysis introduces 'degraded states' or partial failures, and thus provides more insights through finer resolution into the degradation behavior of an item and its progression towards complete failure. The database used for the statistical analysis in the present work identifies five states for each satellite subsystem: three degraded states, one fully operational state, and one failed state (complete failure). Because our dataset is right-censored, we calculate the nonparametric probability of transitioning between states for each satellite subsystem with the Kaplan-Meier estimator, and we derive confidence intervals for each probability of transitioning between states. We then conduct parametric Weibull fits of these probabilities using the Maximum Likelihood Estimation (MLE) approach. After validating the results, we compare the reliability versus multi-state failure analyses of three satellite subsystems: the thruster/fuel; the telemetry, tracking, and control (TTC); and the gyro/sensor/reaction wheel subsystems. The results are particularly revealing of the insights that can be gleaned from multi-state failure analysis and the deficiencies, or blind spots, of the traditional reliability analysis. In addition to the specific results provided here, which should prove particularly useful to the space industry, this work highlights the importance

Satellite data sets for the atmospheric radiation measurement (ARM) program

Energy Technology Data Exchange (ETDEWEB)

Shi, L.; Bernstein, R.L. [SeaSpace Corp., San Diego, CA (United States)

1996-04-01

This abstract describes the type of data obtained from satellite measurements in the Atmospheric Radiation Measurement (ARM) program. The data sets have been widely used by the ARM team to derive cloud-top altitude, cloud cover, snow and ice cover, surface temperature, water vapor, and wind, vertical profiles of temperature, and continuoous observations of weather needed to track and predict severe weather.

Co-ordination of satellite and data programs: The committee on earth observation satellites' approach

Science.gov (United States)

Embleton, B. J. J.; Kingwell, J.

1997-01-01

Every year, an average of eight new civilian remote sensing satellite missions are launched. Cumulatively, over 250 such missions, each with a cost equivalent in current value to between US 100 million to US 1000 million, have been sponsored by space agencies in perhaps two dozen countries. These missions produce data and information products which are vital for informed decision making all over the world, on matters relating to natural resource exploitation, health and safety, sustainable national development, infrastructure planning, and a host of other applications. By contributing to better scientific understanding of global changes in the atmosphere, land surface, oceans and ice caps, these silently orbiting sentinels in the sky make it possible for governments and industries to make wiser environmental policy decisions and support the economic development needs of humanity. The international Committee on Earth Observation Satellites (CEOS) is the premier world body for co-ordinating and planning civilian satellite missions for Earth observation. Through its technical working groups and special task teams, it endeavours to: • maximise the international benefits from Earth observation satellites; and • harmonise practice in calibration, validation, data management and information systems for Earth observation. CEOS encompasses not only space agencies (data providers), but also the great international scientific and operational programs which rely on Earth science data from space. The user organisations affiliated with CEOS, together with the mission operators, attempt to reconcile user needs with the complex set of considerations — including national interests, cost, schedule — which affect the undertaking of space missions. Without such an internationally co-ordinated consensual approach, there is a much greater risk of waste through duplication, and of missed opportunity, or through the absence of measurements of some vital physical or biological

Online Visualization and Analysis of Global Half-Hourly Infrared Satellite Data

Science.gov (United States)

Liu, Zhong; Ostrenga, Dana; Leptoukh, Gregory

2011-01-01

nfrared (IR) images (approximately 11-micron channel) recorded by satellite sensors have been widely used in weather forecasting, research, and classroom education since the Nimbus program. Unlike visible images, IR imagery can reveal cloud features without sunlight illumination; therefore, they can be used to monitor weather phenomena day and night. With geostationary satellites deployed around the globe, it is possible to monitor weather events 24/7 at a temporal resolution that polar-orbiting satellites cannot achieve at the present time. When IR data from multiple geostationary satellites are merged to form a single product--also known as a merged product--it allows for observing weather on a global scale. Its high temporal resolution (e.g., every half hour) also makes it an ideal ancillary dataset for supporting other satellite missions, such as the Tropical Rainfall Measuring Mission (TRMM), etc., by providing additional background information about weather system evolution.

Leveraging the NPS Femto Satellite for Alternative Satellite Communication Networks

Science.gov (United States)

2017-09-01

programmed for eventual integration with the Iridium Network , which is then tested. C. THESIS ORGANIZATION The thesis addresses these questions...NPS FEMTO SATELLITE FOR ALTERNATIVE SATELLITE COMMUNICATION NETWORKS by Faisal S. Alshaya September 2017 Co-Advisors: Steven J. Iatrou...TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE LEVERAGING THE NPS FEMTO SATELLITE FOR ALTERNATIVE SATELLITE COMMUNICATION NETWORKS 5

The possible direct use of satellite radiance measurements by the Atmospheric Radiation Measurement Program

International Nuclear Information System (INIS)

1993-03-01

The Atmospheric Radiation Measurement (ARM) Program is a major research program initiated by the Department of Energy to improve our understanding of radiative and cloud processes critical to predicting the Earth's climate and its changes. Central to this concept is the use of four to six intensively instrumented sites for long-term study and characterization of the processes of interest. The instrumentation suites will include ground-based, high-accuracy radiometers for measuring the short and longwave surface flux, as well as an extensive set of ground-and air-based instrumentation for characterizing the intervening atmospheric column. Satellite-based measurements are expected to play a very important role in providing top-of-the-atmosphere measurements. In this study, we examine the possibility of comparing ARM outputs directly with satellite measurements, thereby ensuring the independence of these two important data sets. Thus we focused on what do satellites really measure and how well do they measure it. On what can we do about the general lack of adequate visible channel calibration. On what is the best way for ARM to obtain near-real-time access to this unprocessed data. And on what is the optimum way for ARM to make use of satellite data

Satellite Imagery Analysis for Automated Global Food Security Forecasting

Science.gov (United States)

Moody, D.; Brumby, S. P.; Chartrand, R.; Keisler, R.; Mathis, M.; Beneke, C. M.; Nicholaeff, D.; Skillman, S.; Warren, M. S.; Poehnelt, J.

2017-12-01

The recent computing performance revolution has driven improvements in sensor, communication, and storage technology. Multi-decadal remote sensing datasets at the petabyte scale are now available in commercial clouds, with new satellite constellations generating petabytes/year of daily high-resolution global coverage imagery. Cloud computing and storage, combined with recent advances in machine learning, are enabling understanding of the world at a scale and at a level of detail never before feasible. We present results from an ongoing effort to develop satellite imagery analysis tools that aggregate temporal, spatial, and spectral information and that can scale with the high-rate and dimensionality of imagery being collected. We focus on the problem of monitoring food crop productivity across the Middle East and North Africa, and show how an analysis-ready, multi-sensor data platform enables quick prototyping of satellite imagery analysis algorithms, from land use/land cover classification and natural resource mapping, to yearly and monthly vegetative health change trends at the structural field level.

LERC-SLAM - THE NASA LEWIS RESEARCH CENTER SATELLITE LINK ATTENUATION MODEL PROGRAM (MACINTOSH VERSION)

Science.gov (United States)

Manning, R. M.

1994-01-01

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

Condensing Massive Satellite Datasets For Rapid Interactive Analysis

Science.gov (United States)

Grant, G.; Gallaher, D. W.; Lv, Q.; Campbell, G. G.; Fowler, C.; LIU, Q.; Chen, C.; Klucik, R.; McAllister, R. A.

2015-12-01

Our goal is to enable users to interactively analyze massive satellite datasets, identifying anomalous data or values that fall outside of thresholds. To achieve this, the project seeks to create a derived database containing only the most relevant information, accelerating the analysis process. The database is designed to be an ancillary tool for the researcher, not an archival database to replace the original data. This approach is aimed at improving performance by reducing the overall size by way of condensing the data. The primary challenges of the project include: - The nature of the research question(s) may not be known ahead of time. - The thresholds for determining anomalies may be uncertain. - Problems associated with processing cloudy, missing, or noisy satellite imagery. - The contents and method of creation of the condensed dataset must be easily explainable to users. The architecture of the database will reorganize spatially-oriented satellite imagery into temporally-oriented columns of data (a.k.a., "data rods") to facilitate time-series analysis. The database itself is an open-source parallel database, designed to make full use of clustered server technologies. A demonstration of the system capabilities will be shown. Applications for this technology include quick-look views of the data, as well as the potential for on-board satellite processing of essential information, with the goal of reducing data latency.

R and D limited partnerships (possible applications in advanced communications satellite technology experiment program)

Science.gov (United States)

1985-01-01

Typical R&D limited partnership arrangements, advantages and disadvantages of R&D limited partnership (RDLPs) and antitrust and tax implications are described. A number of typical forms of RDLPs are described that may be applicable for use in stimulating R&D and experimental programs using the advanced communications technology satellite. The ultimate goal is to increase the rate of market penetration of goods and/or services based upon advanced satellite communications technology. The conditions necessary for these RDLP forms to be advantageous are outlined.

LERC-SLAM - THE NASA LEWIS RESEARCH CENTER SATELLITE LINK ATTENUATION MODEL PROGRAM (IBM PC VERSION)

Science.gov (United States)

Manning, R. M.

1994-01-01

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

Algorithms and programs for processing of satellite data on ozone layer and UV radiation levels

International Nuclear Information System (INIS)

Borkovskij, N.B.; Ivanyukovich, V.A.

2012-01-01

Some algorithms and programs for automatic retrieving and processing ozone layer satellite data are discussed. These techniques are used for reliable short-term UV-radiation levels forecasting. (authors)

Interfering line in trace analysis by X-ray spectrometry: Radiative auger satellites

International Nuclear Information System (INIS)

Maeda, Kuniko; Kawai, Jun.

1994-01-01

Strong characteristic X-ray lines (e.g. Kα and Kβ) are accompanied by broad low-energy satellites caused by the radiative Auger effect (RAE). In order to prove how the RAE satellites interfere the analysis of minor elements, low-energy side spectra of Ca and Ti Kβ, and Ca-Fe Kα were measured. The obtained RAE intensities are summarized together with published experimental and theoretical data. The integrated intensities of satellites due to K → MM, K → LM and K → LL RAE relative to that of Kα are determined to be of the order of 0.01-0.1%. This warns that the neglecting of the RAE satellites will introduce a serious error in trace analysis. (author)

Choosing ESRO's first scientific satellites

Science.gov (United States)

Russo, Arturo

1992-11-01

The choice of the scientific payloads of the European Space Research Organization's (ESRO's) first generation of satellites is analyzed. Concentration is on those aspects of the decision process that involved more directly the scientific community and that emerged as major issues in the discussion of the Launching Program Advisory Committee (LPAC). The main theme was the growing competition between the various fields of space science within the progressive retrenching of the Organization's financial resources available for the satellite program. A general overview of the status of the program by the end of 1966 is presented. The choice of the first small satellites' payloads (ESRO 1 and 2, and HEOS-A) and the difficult definition of the TD satellite program are discussed. This part covers a time span going from early 1963 to the spring of 1966. In the second part, the narrative starts from the spring of 1967, when the decision to recommend a second HEOS-type satellite was taken, and then analyzes the complex situation determined by the crisis of the TD program in 1968, and the debates which eventually led to the abandonment of TD-2 and the start of the far less ambitious ESRO 5 project.

Mobile satellite service communications tests using a NASA satellite

Science.gov (United States)

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

1995-01-01

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

Satellite communications network design and analysis

CERN Document Server

Jo, Kenneth Y

2011-01-01

This authoritative book provides a thorough understanding of the fundamental concepts of satellite communications (SATCOM) network design and performance assessments. You find discussions on a wide class of SATCOM networks using satellites as core components, as well as coverage key applications in the field. This in-depth resource presents a broad range of critical topics, from geosynchronous Earth orbiting (GEO) satellites and direct broadcast satellite systems, to low Earth orbiting (LEO) satellites, radio standards and protocols.This invaluable reference explains the many specific uses of

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

Science.gov (United States)

Pepin, Gerard R.; Hager, E. Paul

1991-01-01

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.

Cladistical Analysis of the Jovian and Saturnian Satellite Systems

Science.gov (United States)

Holt, Timothy. R.; Brown, Adrian. J.; Nesvorný, David; Horner, Jonathan; Carter, Brad

2018-06-01

Jupiter and Saturn each have complex systems of satellites and rings. These satellites can be classified into dynamical groups, implying similar formation scenarios. Recently, a larger number of additional irregular satellites have been discovered around both gas giants that have yet to be classified. The aim of this paper is to examine the relationships between the satellites and rings of the gas giants, using an analytical technique called cladistics. Cladistics is traditionally used to examine relationships between living organisms, the “tree of life.” In this work, we perform the first cladistical study of objects in a planetary science context. Our method uses the orbital, physical, and compositional characteristics of satellites to classify the objects in the Jovian and Saturnian systems. We find that the major relationships between the satellites in the two systems, such as families, as presented in previous studies, are broadly preserved. In addition, based on our analysis of the Jovian system, we identify a new retrograde irregular family, the Iocaste family, and suggest that the Phoebe family of the Saturnian system can be further divided into two subfamilies. We also propose that the Saturnian irregular families be renamed, to be consistent with the convention used in Jovian families. Using cladistics, we are also able to assign the new unclassified irregular satellites into families. Taken together, the results of this study demonstrate the potential use of the cladistical technique in the investigation of relationships between orbital bodies.

Best Longitudinal Adjustment of Satellite Trajectories for the Observation of Forest Fires (Blastoff): A Stochastic Programming Approach to Satellite System Design

Science.gov (United States)

Hoskins, Aaron B.

Forest fires cause a significant amount of damage and destruction each year. Optimally dispatching resources reduces the amount of damage a forest fire can cause. Models predict the fire spread to provide the data required to optimally dispatch resources. However, the models are only as accurate as the data used to build them. Satellites are one valuable tool in the collection of data for the forest fire models. Satellites provide data on the types of vegetation, the wind speed and direction, the soil moisture content, etc. The current operating paradigm is to passively collect data when possible. However, images from directly overhead provide better resolution and are easier to process. Maneuvering a constellation of satellites to fly directly over the forest fire provides higher quality data than is achieved with the current operating paradigm. Before launch, the location of the forest fire is unknown. Therefore, it is impossible to optimize the initial orbits for the satellites. Instead, the expected cost of maneuvering to observe the forest fire determines the optimal initial orbits. A two-stage stochastic programming approach is well suited for this class of problem where initial decisions are made with an uncertain future and then subsequent decisions are made once a scenario is realized. A repeat ground track orbit provides a non-maneuvering, natural solution providing a daily flyover of the forest fire. However, additional maneuvers provide a second daily flyover of the forest fire. The additional maneuvering comes at a significant cost in terms of additional fuel, but provides more data collection opportunities. After data are collected, ground stations receive the data for processing. Optimally selecting the ground station locations reduce the number of built ground stations and reduces the data fusion issues. However, the location of the forest fire alters the optimal ground station sites. A two-stage stochastic programming approach optimizes the

A systems approach to the commercialization of space communications technology - The NASA/JPL Mobile Satellite Program

Science.gov (United States)

Weber, William J., III; Gray, Valerie W.; Jackson, Byron; Steele, Laura C.

1991-10-01

This paper discusss the systems approach taken by NASA and the Jet Propulsion Laboratory in the commercialization of land-mobile satellite services (LMSS) in the United States. As the lead center for NASA's Mobile Satellite Program, JPL was involved in identifying and addressing many of the key barriers to commercialization of mobile satellite communications, including technical, economic, regulatory and institutional risks, or uncertainties. The systems engineering approach described here was used to mitigate these risks. The result was the development and implementation of the JPL Mobile Satellite Experiment Project. This Project included not only technology development, but also studies to support NASA in the definition of the regulatory, market, and investment environments within which LMSS would evolve and eventually operate, as well as initiatives to mitigate their associated commercialization risks. The end result of these government-led endeavors was the acceleration of the introduction of commercial mobile satellite services, both nationally and internationally.

Advanced Satellite Workstation - An integrated workstation environment for operational support of satellite system planning and analysis

Science.gov (United States)

Hamilton, Marvin J.; Sutton, Stewart A.

A prototype integrated environment, the Advanced Satellite Workstation (ASW), which was developed and delivered for evaluation and operator feedback in an operational satellite control center, is described. The current ASW hardware consists of a Sun Workstation and Macintosh II Workstation connected via an ethernet Network Hardware and Software, Laser Disk System, Optical Storage System, and Telemetry Data File Interface. The central objective of ASW is to provide an intelligent decision support and training environment for operator/analysis of complex systems such as satellites. Compared to the many recent workstation implementations that incorporate graphical telemetry displays and expert systems, ASW provides a considerably broader look at intelligent, integrated environments for decision support, based on the premise that the central features of such an environment are intelligent data access and integrated toolsets.

A graphics approach in the design of the dual air density Explorer satellites

Science.gov (United States)

Mcdougal, D. S.

1975-01-01

A computer program was developed to generate a graphics display of the Dual Air Density (DAD) Explorer satellites which aids in the engineering and scientific design. The program displays a two-dimensional view of both spacecraft and their surface features from any direction. The graphics have been an indispensable tool in the design, analysis, and understanding of the critical locations of the various surface features for both satellites.

Improved candidate generation and coverage analysis methods for design optimization of symmetric multi-satellite constellations

Science.gov (United States)

Matossian, Mark G.

1997-01-01

Much attention in recent years has focused on commercial telecommunications ventures involving constellations of spacecraft in low and medium Earth orbit. These projects often require investments on the order of billions of dollars (US$) for development and operations, but surprisingly little work has been published on constellation design optimization for coverage analysis, traffic simulation and launch sequencing for constellation build-up strategies. This paper addresses the two most critical aspects of constellation orbital design — efficient constellation candidate generation and coverage analysis. Inefficiencies and flaws in the current standard algorithm for constellation modeling are identified, and a corrected and improved algorithm is presented. In the 1970's, John Walker and G. V. Mozhaev developed innovative strategies for continuous global coverage using symmetric non-geosynchronous constellations. (These are sometimes referred to as rosette, or Walker constellations. An example is pictured above.) In 1980, the late Arthur Ballard extended and generalized the work of Walker into a detailed algorithm for the NAVSTAR/GPS program, which deployed a 24 satellite symmetric constellation. Ballard's important contribution was published in his "Rosette Constellations of Earth Satellites."

Analysis on Space Environment from the Anomalies of Geosynchronous Satellites

Directory of Open Access Journals (Sweden)

Jaejin Lee

2009-12-01

Full Text Available While it is well known that space environment can produce spacecraft anomaly, defining space environment effects for each anomalies is difficult. This is caused by the fact that spacecraft anomaly shows various symptoms and reproducing it is impossible. In this study, we try to find the conditions of when spacecraft failures happen more frequently and give satellite operators useful information. Especially, our study focuses on the geosynchronous satellites which cost is high and required high reliability. We used satellite anomaly data given by Satellite News Digest which is internet newspaper providing space industry news. In our analysis, 88 anomaly cases occurred from 1997 to 2008 shows bad corelation with Kp index. Satellite malfunctions were likely to happen in spring and fall and in local time from midnight to dawn. In addition, we found the probability of anomaly increase when high energy electron flux is high. This is more clearly appeared in solar minimum than maximum period.

Thermal Analysis of Iodine Satellite (iSAT)

Science.gov (United States)

Mauro, Stephanie

2015-01-01

This paper presents the progress of the thermal analysis and design of the Iodine Satellite (iSAT). The purpose of the iSAT spacecraft (SC) is to demonstrate the ability of the iodine Hall Thruster propulsion system throughout a one year mission in an effort to mature the system for use on future satellites. The benefit of this propulsion system is that it uses a propellant, iodine, that is easy to store and provides a high thrust-to-mass ratio. The spacecraft will also act as a bus for an earth observation payload, the Long Wave Infrared (LWIR) Camera. Four phases of the mission, determined to either be critical to achieving requirements or phases of thermal concern, are modeled. The phases are the Right Ascension of the Ascending Node (RAAN) Change, Altitude Reduction, De-Orbit, and Science Phases. Each phase was modeled in a worst case hot environment and the coldest phase, the Science Phase, was also modeled in a worst case cold environment. The thermal environments of the spacecraft are especially important to model because iSAT has a very high power density. The satellite is the size of a 12 unit cubesat, and dissipates slightly more than 75 Watts of power as heat at times. The maximum temperatures for several components are above their maximum operational limit for one or more cases. The analysis done for the first Design and Analysis Cycle (DAC1) showed that many components were above or within 5 degrees Centigrade of their maximum operation limit. The battery is a component of concern because although it is not over its operational temperature limit, efficiency greatly decreases if it operates at the currently predicted temperatures. In the second Design and Analysis Cycle (DAC2), many steps were taken to mitigate the overheating of components, including isolating several high temperature components, removal of components, and rearrangement of systems. These changes have greatly increased the thermal margin available.

New Opportunitie s for Small Satellite Programs Provided by the Falcon Family of Launch Vehicles

Science.gov (United States)

Dinardi, A.; Bjelde, B.; Insprucker, J.

2008-08-01

The Falcon family of launch vehicles, developed by Space Exploration Technologies Corporation (SpaceX), are designed to provide the world's lowest cost access to orbit. Highly reliable, low cost launch services offer considerable opportunities for risk reduction throughout the life cycle of satellite programs. The significantly lower costs of Falcon 1 and Falcon 9 as compared with other similar-class launch vehicles results in a number of new business case opportunities; which in turn presents the possibility for a paradigm shift in how the satellite industry thinks about launch services.

Upper atmosphere research satellite program. [to study the chemistry energetics, and dynamics

Science.gov (United States)

Huntress, W. T., Jr.

1978-01-01

A satellite program to conduct research on the chemistry, energetics, and dynamics of the upper atmosphere was developed. The scientific goals of the Upper Atmospheric Research Program, the program requirements, and the approach toward meeting those requirements are outlined. An initial series of two overlapping spacecraft missions is described. Both spacecraft are launched and recovered by the STS, one in the winter of 1983 at a 56 deg inclination, and the other a year later at a 70 deg inclination. The duration of each mission is 18 months, and each carries instruments to make global measurements of the temperature, winds, composition, irradation, and radiance in the stratosphere, mesosphere, and lower thermosphere between the tropopause and 120 km altitude. The program requires a dedicated ground-based data system and a science team organization that leads to a strong interaction between the experiments and theory. The program includes supportive observations from other platforms such as rockets, balloons, and the Spacelab.

Shuttle user analysis (study 2.2): Volume 3. Business Risk And Value of Operations in space (BRAVO). Part 4: Computer programs and data look-up

Science.gov (United States)

1974-01-01

Computer program listings as well as graphical and tabulated data needed by the analyst to perform a BRAVO analysis were examined. Graphical aid which can be used to determine the earth coverage of satellites in synchronous equatorial orbits was described. A listing for satellite synthesis computer program as well as a sample printout for the DSCS-11 satellite program and a listing of the symbols used in the program were included. The APL language listing for the payload program cost estimating computer program was given. This language is compatible with many of the time sharing remote terminals computers used in the United States. Data on the intelsat communications network was studied. Costs for telecommunications systems leasing, line of sight microwave relay communications systems, submarine telephone cables, and terrestrial power generation systems were also described.

Improving Eastern Bluebird nest box performance using computer analysis of satellite images

Directory of Open Access Journals (Sweden)

Sarah Svatora

2012-06-01

Full Text Available Bird conservationists have been introducing man-made boxes in an effort to increase the bluebird population. In this study we use computer analysis of satellite images to show that the performance of the boxes used by Eastern Bluebirds (Sialia sialis in Michigan can be improved by about 48%. The analysis is based on a strongcorrelation found between the edge directionality measured in the satellite image of the area around the box, and the preferences of the birds when selecting their nesting site. The method is based on satellite images taken from Google Earth, and can be used by conservationists to select a box placement strategy that will optimize the efficacy of the boxes deployed in a given area.

Structural Analysis of Components of the Students for the Exploration and Development of Space Satellite (SEDSAT) for the Small Expendable Deployer System (SEDS) Project Office

Science.gov (United States)

Maddux, Gary A.

1998-01-01

During the time frame allocated by the delivery order, members of the UAH Applied Research Program, with the cooperation of representatives from NASA investigated and conducted stress analysis of the SEDSAT1 satellite. The main area of concern was with the design of the deployable 10 m antennas. The placement of the holes for the antenna door hinge pin was too close to the edge of the antenna canister. Because of the load placed on the hinge pin, the stress analysis of this area suggested that more space would be needed between the holes and the edge of the material. Due to other conflicts, SEDSATI was removed from flying on the space shuttle and moved to the Delta Launch Vehicle. This changed many of the design requirements for the mounting and deployment of the satellite that forced a new design for the satellite. Once this happened, the stress analysis became obsolete, and the task was concluded.

Automatic Satellite Telemetry Analysis for SSA using Artificial Intelligence Techniques

Science.gov (United States)

Stottler, R.; Mao, J.

In April 2016, General Hyten, commander of Air Force Space Command, announced the Space Enterprise Vision (SEV) (http://www.af.mil/News/Article-Display/Article/719941/hyten-announces-space-enterprise-vision/). The SEV addresses increasing threats to space-related systems. The vision includes an integrated approach across all mission areas (communications, positioning, navigation and timing, missile warning, and weather data) and emphasizes improved access to data across the entire enterprise and the ability to protect space-related assets and capabilities. "The future space enterprise will maintain our nation's ability to deliver critical space effects throughout all phases of conflict," Hyten said. Satellite telemetry is going to become available to a new audience. While that telemetry information should be valuable for achieving Space Situational Awareness (SSA), these new satellite telemetry data consumers will not know how to utilize it. We were tasked with applying AI techniques to build an infrastructure to process satellite telemetry into higher abstraction level symbolic space situational awareness and to initially populate that infrastructure with useful data analysis methods. We are working with two organizations, Montana State University (MSU) and the Air Force Academy, both of whom control satellites and therefore currently analyze satellite telemetry to assess the health and circumstances of their satellites. The design which has resulted from our knowledge elicitation and cognitive task analysis is a hybrid approach which combines symbolic processing techniques of Case-Based Reasoning (CBR) and Behavior Transition Networks (BTNs) with current Machine Learning approaches. BTNs are used to represent the process and associated formulas to check telemetry values against anticipated problems and issues. CBR is used to represent and retrieve BTNs that represent an investigative process that should be applied to the telemetry in certain circumstances

Estimating Rain Attenuation In Satellite Communication Links

Science.gov (United States)

Manning, R. M.

1991-01-01

Attenuation computed with help of statistical model and meteorological data. NASA Lewis Research Center Satellite Link Attenuation Model (SLAM) program QuickBASIC computer program evaluating static and dynamic statistical assessment of impact of rain attenuation on communication link established between Earth terminal and geosynchronous satellite. Application in specification, design, and assessment of satellite communication links for any terminal location in continental United States. Written in Microsoft QuickBASIC.

Computing Thermal Imbalance Forces On Satellites

Science.gov (United States)

Vigue, Yvonne; Schutz, Robert E.; Sewell, Granville; Abusali, Pothai A. M.

1994-01-01

HEAT.PRO computer program calculates imbalance force caused by heating of surfaces of satellite. Calculates thermal imbalance force and determines its effect on orbit of satellite, especially where shadow cast by Earth Causes periodic changes in thermal environment around satellite. Written in FORTRAN 77.

A Tool and Application Programming Interface for Browsing Historical Geostationary Satellite Data

Science.gov (United States)

Chee, T.; Nguyen, L.; Minnis, P.; Spangenberg, D.; Ayers, J.

2013-12-01

Providing access to information is a key concern for NASA Langley Research Center. We describe a tool and method that allows end users to easily browse and access information that is otherwise difficult to acquire and manipulate. The tool described has as its core the application-programming interface that is made available to the public. One goal of the tool is to provide a demonstration to end users so that they can use the enhanced imagery as an input into their own work flows. This project builds upon NASA Langley Cloud and Radiation Group's experience with making real-time and historical satellite imagery accessible and easily searchable. As we see the increasing use of virtual supply chains that provide additional value at each link there is value in making satellite imagery available through a simple access method as well as allowing users to browse and view that imagery as they need rather than in a manner most convenient for the data provider.

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

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

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.

Detection and Extraction of Roads from High Resolution Satellites Images with Dynamic Programming

Science.gov (United States)

Benzouai, Siham; Smara, Youcef

2010-12-01

The advent of satellite images allows now a regular and a fast digitizing and update of geographic data, especially roads which are very useful for Geographic Information Systems (GIS) applications such as transportation, urban pollution, geomarketing, etc. For this, several studies have been conducted to automate roads extraction in order to minimize the manual processes [4]. In this work, we are interested in roads extraction from satellite imagery with high spatial resolution (at best equal to 10 m). The method is semi automatic and follows a linear approach where road is considered as a linear object. As roads extraction is a pattern recognition problem, it is useful, above all, to characterize roads. After, we realize a pre-processing by applying an Infinite Size Edge Filter -ISEF- and processing method based on dynamic programming concept, in particular, Fishler algorithm designed by F*.

The ground support computer and in-orbit survey data analysis program for the SEEP experiment

International Nuclear Information System (INIS)

Voss, H.D.; Datlowe, D.W.; Mobilia, J.; Roselle, S.N.

1985-01-01

The ground support computer equipment (GSE) and production survey plot and analysis software are described for the Stimulated Emissions of Energetic Particles (SEEP) experiment on the S81-1 satellite. A general purpose satellite data acquisition circuit was developed based on a Z-80 portable microcomputer. By simply changing instrument control software and electrical connectors, automatic testing and control of the various SEEP instruments was accomplished. A new feature incorporated into the SEEP data analysis phase was the development of a correlative data base for all of the SEEP instruments. A CPU efficient survey plot program (with ephemeris) was developed to display the approximate 3100 hours of data, with a time resolution of 0.5 sec, from the ten instrument sensors. The details of the general purpose multigraph algorithms and plot formats are presented. For the first time new associations are being investigated of simultaneous particle, X-ray, optical and plasma density satellite measurements

Failure analysis of satellite subsystems to define suitable de-orbit devices

Science.gov (United States)

Palla, Chiara; Peroni, Moreno; Kingston, Jennifer

2016-11-01

Space missions in Low Earth Orbit (LEO) are severely affected by the build-up of orbital debris. A key practice, to be compliant with IADC (Inter-Agency Space Debris Coordination Committee) mitigation guidelines, is the removal of space systems that interfere with the LEO region not later than 25 years after the End of Mission. It is important to note that the current guidelines are not generally legally binding, even if different Space Agencies are now looking at the compliance for their missions. If the guidelines will change in law, it will be mandatory to have a postmission disposal strategy for all satellites, including micro and smaller classes. A potential increased number of these satellites is confirmed by different projections, in particular in the commercial sector. Micro and smaller spacecraft are, in general, not provided with propulsion capabilities to achieve a controlled re-entry, so they need different de-orbit disposal methods. When considering the utility of different debris mitigation methods, it is useful to understand which spacecraft subsystems are most likely to fail and how this may affect the operation of a de-orbit system. This also helps the consideration of which components are the most relevant or should be redundant depending on the satellite mass class. This work is based on a sample of LEO and MEO satellites launched between January 2000 and December 2014 with mass lower than 1000 kg. Failure analysis of satellite subsystems is performed by means of the Kaplan-Meier survival analysis; the parametric fits are conducted with Weibull distributions. The study is carried out by using the satellite database SpaceTrak™ which provides anomalies, failures, and trends information for spacecraft subsystems and launch vehicles. The database identifies five states for each satellite subsystem: three degraded states, one fully operational state, and one failed state (complete failure). The results obtained can guide the identification of the

Earth rotation, station coordinates and orbit determination from satellite laser ranging

Science.gov (United States)

Murata, Masaaki

The Project MERIT, a special program of international colaboration to Monitor Earth Rotation and Intercompare the Techniques of observation and analysis, has come to an end with great success. Its major objective was to evaluate the ultimate potential of space techniques such as VLBI and satellite laser ranging, in contrast with the other conventional techniques, in the determination of rotational dynamics of the earth. The National Aerospace Laboratory (NAL) has officially participated in the project as an associate analysis center for satellite laser technique for the period of the MERIT Main Campaign (September 1983-October 1984). In this paper, the NAL analysis center results are presented.

Satellite Cell Self-Renewal.

Science.gov (United States)

Giordani, Lorenzo; Parisi, Alice; Le Grand, Fabien

2018-01-01

Adult skeletal muscle is endowed with regenerative potential through partially recapitulating the embryonic developmental program. Upon acute injury or in pathological conditions, quiescent muscle-resident stem cells, called satellite cells, become activated and give rise to myogenic progenitors that massively proliferate, differentiate, and fuse to form new myofibers and restore tissue functionality. In addition, a proportion of activated cells returns back to quiescence and replenish the pool of satellite cells in order to maintain the ability of skeletal muscle tissue to repair. Self-renewal is the process by which stem cells divide to make more stem cells to maintain the stem cell population throughout life. This process is controlled by cell-intrinsic transcription factors regulated by cell-extrinsic signals from the niche and the microenvironment. This chapter provides an overview about the general aspects of satellite cell biology and focuses on the cellular and molecular aspects of satellite cell self-renewal. To date, we are still far from understanding how a very small proportion of the satellite cell progeny maintain their stem cell identity when most of their siblings progress through the myogenic program to construct myofibers. © 2018 Elsevier Inc. All rights reserved.

Rural Satellite Services--Getting the Mixture Right.

Science.gov (United States)

Stahmer, Anna

1987-01-01

This discussion of satellite services for education and rural development in less developed countries emphasizes the importance of adequate telephone systems to support development programs. Programs in Peru, Indonesia, and the West Indies are highlighted, and current and future problems in planning satellite systems are reviewed. (LRW)

DS-CDMA satellite diversity reception for personal satellite communication: Downlink performance analysis

Science.gov (United States)

DeGaudenzi, Riccardo; Giannetti, Filippo

1995-01-01

The downlink of a satellite-mobile personal communication system employing power-controlled Direct Sequence Code Division Multiple Access (DS-CDMA) and exploiting satellite-diversity is analyzed and its performance compared with a more traditional communication system utilizing single satellite reception. The analytical model developed has been thoroughly validated by means of extensive Monte Carlo computer simulations. It is shown how the capacity gain provided by diversity reception shrinks considerably in the presence of increasing traffic or in the case of light shadowing conditions. Moreover, the quantitative results tend to indicate that to combat system capacity reduction due to intra-system interference, no more than two satellites shall be active over the same region. To achieve higher system capacity, differently from terrestrial cellular systems, Multi-User Detection (MUD) techniques are likely to be required in the mobile user terminal, thus considerably increasing its complexity.

Analysis of orbit determination from Earth-based tracking for relay satellites in a perturbed areostationary orbit

Science.gov (United States)

Romero, P.; Pablos, B.; Barderas, G.

2017-07-01

Areostationary satellites are considered a high interest group of satellites to satisfy the telecommunications needs of the foreseen missions to Mars. An areostationary satellite, in an areoequatorial circular orbit with a period of 1 Martian sidereal day, would orbit Mars remaining at a fixed location over the Martian surface, analogous to a geostationary satellite around the Earth. This work addresses an analysis of the perturbed orbital motion of an areostationary satellite as well as a preliminary analysis of the aerostationary orbit estimation accuracy based on Earth tracking observations. First, the models for the perturbations due to the Mars gravitational field, the gravitational attraction of the Sun and the Martian moons, Phobos and Deimos, and solar radiation pressure are described. Then, the observability from Earth including possible occultations by Mars of an areostationary satellite in a perturbed areosynchronous motion is analyzed. The results show that continuous Earth-based tracking is achievable using observations from the three NASA Deep Space Network Complexes in Madrid, Goldstone and Canberra in an occultation-free scenario. Finally, an analysis of the orbit determination accuracy is addressed considering several scenarios including discontinuous tracking schedules for different epochs and different areoestationary satellites. Simulations also allow to quantify the aerostationary orbit estimation accuracy for various tracking series durations and observed orbit arc-lengths.

Space environment monitoring by low-altitude operational satellites

International Nuclear Information System (INIS)

Kroehl, H.W.

1982-01-01

The primary task of the Defense Meteorological Satellite Program (DMSP) is the acquisition of meteorological data in the visual and infrared spectral regions. The Air Weather Service operates two satellites in low-altitude, sun-synchronous, polar orbits at 850 km altitude, 98.7 deg inclination, 101.5 minute period and dawn-dusk or noon-midnight equatorial crossing times. Special DMSP sensors of interest to the space science community are the precipitating electron spectrometer, the terrestrial noise receiver, and the topside ionosphere plasma monitor. Data from low-altitude, meteorological satellites can be used to build empirical models of precipitating electron characteristics of the auroral zone and polar cap. The Tiros-NOAA satellite program complements the DMSP program. The orbital elements are the same as DMSP's, except for the times of equatorial crossing, and the tilt of the orbital plane. The Tiros-NOAA program meets the civilian community's needs for meteorological data as the DMSP program does for the military

Quantifying offshore wind resources from satellite wind maps: Study area the North Sea

DEFF Research Database (Denmark)

Hasager, Charlotte Bay; Barthelmie, Rebecca Jane; Christiansen, Merete B.

2006-01-01

Offshore wind resources are quantified from satellite synthetic aperture radar (SAR) and satellite scatterometer observations at local and regional scale respectively at the Horns Rev site in Denmark. The method for wind resource estimation from satellite observations interfaces with the wind atlas...... of the Horns Rev wind farm is quantified from satellite SAR images and compared with state-of-the-art wake model results with good agreement. It is a unique method using satellite observations to quantify the spatial extent of the wake behind large offshore wind farms. Copyright © 2006 John Wiley & Sons, Ltd....... analysis and application program (WAsP). An estimate of the wind resource at the new project site at Horns Rev is given based on satellite SAR observations. The comparison of offshore satellite scatterometer winds, global model data and in situ data shows good agreement. Furthermore, the wake effect...

Combining airborne and satellite remote sensing programs to repress illegal oil discharges in restricted sea areas

International Nuclear Information System (INIS)

Price, M.

2005-01-01

An airborne surveillance program has been conducted over the Belgian part of the North Sea since 1991. The role of the program is to detect infringements on the Marpol Convention via remote sensing, and to take legal action against polluters through the use of recorded observations. Although Belgium has a restricted sea area of about 3,500 km with no fixed offshore oil installations, a pollution risk is constantly present due to 2 dense traffic separation schemes close to the shoreline. The Belgian marine areas and adjacent waters are regularly scanned with a Side Looking Airborne Radar (SLAR) on board a remote sensing aircraft. This paper describes an evaluation trial that the Belgian Management Unit of the North Sea Mathematical Models (MUMM) joined in 2004, together with various agencies from the United Kingdom, Germany and the Netherlands. The trial consists of a cost-sharing satellite service for oil detection with ENVISAT ASAR data. The trial was co-funded by the European Space Agency (ESA) and run by Kongsberg Satellite Services. MUMM's objective was to evaluate the effectiveness and operational character of satellite services for detecting oil spills at sea. The results of the 3 month trial have indicated that aerial remote sensing for the detection of illegal oil discharges at sea increases the chances of catching polluters more efficiently, with improved chances of evidence collecting. It was concluded that when various services are integrated and strict operational conditions are met, satellite services may prove to be valuable in restricted, very densely navigated national waters that are easily reached by airborne means. 12 refs., 8 tabs., 3 figs

Theory of geostationary satellites

CERN Document Server

Zee, Chong-Hung

1989-01-01

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...

The large satellite program of ESA and its relevance for broadcast missions

Science.gov (United States)

Fromm, H.-H.; Herdan, B. L.

1981-03-01

In an investigation of the market prospects and payload requirements of future communications satellites, it was concluded that during the next 15 years many space missions will demand larger satellite platforms than those currently available. These platforms will be needed in connection with direct-broadcasting satellites, satellites required to enhance capacities in the case of traditional services, and satellites employed to introduce new types of satellite-based communications operating with small terminals. Most of the larger satellites would require the Ariane III capability, corresponding to about 1400 kg satellite mass in geostationary orbit. Attention is given to L-SAT platform capabilities and broadcast payload requirements, taking into account a European direct-broadcast satellite and Canadian direct-broadcast missions.

System Critical Design Audit (CDA). Books 1, 2 and 3; [Small Satellite Technology Initiative (SSTI Lewis Spacecraft Program)

Science.gov (United States)

1995-01-01

Small Satellite Technology Initiative (SSTI) Lewis Spacecraft Program is evaluated. Spacecraft integration, test, launch, and spacecraft bus are discussed. Payloads and technology demonstrations are presented. Mission data management system and ground segment are also addressed.

Analysis of transmission speed of AX.25 Protocol implemented in satellital earth station UPTC

Directory of Open Access Journals (Sweden)

Oscar Fernando Vera Cely

2015-11-01

Full Text Available One of the important parameters for the proper functioning of satellital ground station projected on Pedagogical and Technological University of Colombia (UPTC is the efficiency in transmission speed on communications protocol. This paper shows the results of analysis of the transmission speed of the AX.25 protocol implemented in the communication system of the satellital ground station UPTC. It begins with a brief description of the implemented hardware; the behavior of the transmission rate is evaluated using a theoretical analysis based on equations to estimate this parameter in the operation of the protocol, then tests are performed using the hardware that the satellital ground station UPTC has and finally, the conclusions are presented. Based on comparison of the theoretical analysis results obtained experimentally, it became apparent that AX.25 protocol efficiency is higher when increasing the number of frames.

Inserts thermal coupling analysis in hexagonal honeycomb plates used for satellite structural design

International Nuclear Information System (INIS)

Boudjemai, A.; Mankour, A.; Salem, H.; Amri, R.; Hocine, R.; Chouchaoui, B.

2014-01-01

Mechanical joints and fasteners are essential elements in joining structural components in mechanical systems. The thermal coupling effect between the adjacent inserts depends to a great extent on the thermal properties of the inserts and the clearance. In this paper the Finite-Element Method (FEM) has been employed to study the insert thermal coupling behaviour of the hexagonal honeycomb panel. Fully coupled thermal analysis was conducted in order to predict thermal coupling phenomena caused by the adjacent inserts under extreme thermal loading conditions. Detailed finite elements models for a honeycomb panel are developed in this study including the insert joints. New approach of the adhesive joint is modelled. Thermal simulations showed that the adjacent inserts cause thermal interference and the adjacent inserts are highly sensitive to the effect of high temperatures. The clearance and thermal interference between the adjacent inserts have an important influence on the satellite equipments (such as the electronics box), which can cause the satellite equipments failures. The results of the model presented in this analysis are significant in the preliminary satellites structural dimensioning which present an effective approach of development by reducing the cost and the time of analysis. - Highlights: •In this work we perform thermal analysis of honeycomb plates using finite element method. •Detailed finite elements models for honeycomb panel are developed in this study including the insert joints. •New approach of the adhesive joint is modelled. •The adjacent inserts cause the thermal interference. •We conclude that this work will help in the analysis and the design of complex satellite structures

The Use of a Satellite Human Interaction System in Conjunction with a Satellite Media Distribution System. Satellite Technology Demonstration, Technical Report No. 0217.

Science.gov (United States)

Dale, Joyce B.

Satellite Technology Demonstration (STD) was designed to provide data on the use of a satellite to deliver educational programs to 56 rural-isolated schools in eight Rocky Mountain States. Three series were broadcast: (1) a junior high school career development, (2) career development for public school administrators and teachers, and (3) topical…

NOAA's Joint Polar Satellite System's (JPSS) Proving Ground and Risk Reduction (PGRR) Program - Bringing JPSS Science into Support of Key NOAA Missions!

Science.gov (United States)

Sjoberg, W.; McWilliams, G.

2017-12-01

This presentation will focus on the continuity of the NOAA Joint Polar Satellite System (JPSS) Program's Proving Ground and Risk Reduction (PGRR) and key activities of the PGRR Initiatives. The PGRR Program was established in 2012, following the launch of the Suomi National Polar Partnership (SNPP) satellite. The JPSS Program Office has used two PGRR Project Proposals to establish an effective approach to managing its science and algorithm teams in order to focus on key NOAA missions. The presenter will provide details of the Initiatives and the processes used by the initiatives that have proven so successful. Details of the new 2017 PGRR Call-for-Proposals and the status of project selections will be discussed.

Environmental Testing Philosophy for a Sandia National Laboratories' Small Satellite Project - A Retrospective

Energy Technology Data Exchange (ETDEWEB)

CAP,JEROME S.

2000-08-24

Sandia has recently completed the flight certification test series for the Multi-Spectral Thermal Imaging satellite (MTI), which is a small satellite for which Sandia was the system integrator. A paper was presented at the 16th Aerospace Testing Seminar discussing plans for performing the structural dynamics certification program for that satellite. The testing philosophy was originally based on a combination of system level vibroacoustic tests and component level shock and vibration tests. However, the plans evolved to include computational analyses using both Finite Element Analysis and Statistical Energy Analysis techniques. This paper outlines the final certification process and discuss lessons learned including both things that went well and things that should/could have been done differently.

A Land Product Characterization System for Comparative Analysis of Satellite Data and Products

Directory of Open Access Journals (Sweden)

Kevin Gallo

2017-12-01

Full Text Available A Land Product Characterization System (LPCS has been developed to provide land data and products to the community of individuals interested in validating space-based land products by comparing them with similar products available from other sensors or surface-based observations. The LPCS facilitates the application of global multi-satellite and in situ data for characterization and validation of higher-level, satellite-derived, land surface products (e.g., surface reflectance, normalized difference vegetation index, and land surface temperature. The LPCS includes data search, inventory, access, and analysis functions that will permit data to be easily identified, retrieved, co-registered, and compared statistically through a single interface. The system currently includes data and products available from Landsat 4 through 8, Moderate Resolution Imaging Spectroradiometer (MODIS Terra and Aqua, Suomi National Polar-Orbiting Partnership (S-NPP/Joint Polar Satellite System (JPSS Visible Infrared Imaging Radiometer Suite (VIIRS, and simulated data for the Geostationary Operational Environmental Satellite (GOES-16 Advanced Baseline Imager (ABI. In addition to the future inclusion of in situ data, higher-level land products from the European Space Agency (ESA Sentinel-2 and -3 series of satellites, and other high and medium resolution spatial sensors, will be included as available. When fully implemented, any of the sensor data or products included in the LPCS would be available for comparative analysis.

Northern Everglades, Florida, satellite image map

Science.gov (United States)

Thomas, Jean-Claude; Jones, John W.

2002-01-01

These satellite image maps are one product of the USGS Land Characteristics from Remote Sensing project, funded through the USGS Place-Based Studies Program with support from the Everglades National Park. The objective of this project is to develop and apply innovative remote sensing and geographic information system techniques to map the distribution of vegetation, vegetation characteristics, and related hydrologic variables through space and over time. The mapping and description of vegetation characteristics and their variations are necessary to accurately simulate surface hydrology and other surface processes in South Florida and to monitor land surface changes. As part of this research, data from many airborne and satellite imaging systems have been georeferenced and processed to facilitate data fusion and analysis. These image maps were created using image fusion techniques developed as part of this project.

Environmental assessment for the satellite power system concept development and evaluation program: nonmicrowave health and ecological effects

Energy Technology Data Exchange (ETDEWEB)

White, M R

1980-11-01

A Concept Development and Evaluation Program is being carried out for a proposed Satellite Power System (SPS). For purposes of this evaluation, a preliminary reference system has been developed. SPS, as described in the reference system, would collect solar energy on satellites in geosychronous orbit in space. The energy would be converted to microwaves and beamed to an earth-receiving antenna (rectenna). One task in the environmental part of the program is the assessment of the nonmicrowave effects on health and the environment. These effects would result from all phases of SPS development and operation. This report covers the current knowledge regarding these effects, and is based on the reference system. The assessment is summarized as to scope, methodology, impacts of terrestrial development, launch and recovery of spacecraft, space activities (including health effects of the space environment, ionizing radiation, electromagnetic exposure, spacecraft charging and environmental interactions, occupational hazards, etc.) and construction and operation of rectenna (ground receiving station).

Environmental assessment for the satellite power system concept development and evaluation program: nonmicrowave health and ecological effects

International Nuclear Information System (INIS)

White, M.R.

1980-11-01

A Concept Development and Evaluation Program is being carried out for a proposed Satellite Power System (SPS). For purposes of this evaluation, a preliminary reference system has been developed. SPS, as described in the reference system, would collect solar energy on satellites in geosychronous orbit in space. The energy would be converted to microwaves and beamed to an earth-receiving antenna (rectenna). One task in the environmental part of the program is the assessment of the nonmicrowave effects on health and the environment. These effects would result from all phases of SPS development and operation. This report covers the current knowledge regarding these effects, and is based on the reference system. The assessment is summarized as to scope, methodology, impacts of terrestrial development, launch and recovery of spacecraft, space activities (including health effects of the space environment, ionizing radiation, electromagnetic exposure, spacecraft charging and environmental interactions, occupational hazards, etc.) and construction and operation of rectenna

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

Science.gov (United States)

Lonsdale, Helen C.

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

Earth mapping - aerial or satellite imagery comparative analysis

Science.gov (United States)

Fotev, Svetlin; Jordanov, Dimitar; Lukarski, Hristo

Nowadays, solving the tasks for revision of existing map products and creation of new maps requires making a choice of the land cover image source. The issue of the effectiveness and cost of the usage of aerial mapping systems versus the efficiency and cost of very-high resolution satellite imagery is topical [1, 2, 3, 4]. The price of any remotely sensed image depends on the product (panchromatic or multispectral), resolution, processing level, scale, urgency of task and on whether the needed image is available in the archive or has to be requested. The purpose of the present work is: to make a comparative analysis between the two approaches for mapping the Earth having in mind two parameters: quality and cost. To suggest an approach for selection of the map information sources - airplane-based or spacecraft-based imaging systems with very-high spatial resolution. Two cases are considered: area that equals approximately one satellite scene and area that equals approximately the territory of Bulgaria.

Satellite Radio

Indian Academy of Sciences (India)

Satellites have been a highly effective platform for multi- form broadcasts. This has led to a ... diversity offormats, languages, genre, and a universal reach that cannot be met by .... programs can be delivered to whom it is intended. In the case of.

Satellite Based Live and Interactive Distance Learning Program in the Field of Geoinformatics - a Perspective of Indian Institute of Remote Sensing, India

Science.gov (United States)

Raju, P. L. N.; Gupta, P. K.; Roy, P. S.

2011-09-01

Geoinformatics is a highly specialized discipline that deals with Remote Sensing, Geographical Information System (GIS), Global Positioning System (GPS) and field surveys for assessing, quantification, development and management of resources, planning and infrastructure development, utility services etc. Indian Institute of Remote Sensing (IIRS), a premier institute and one of its kinds has played a key role for capacity Building in this specialized area since its inception in 1966. Realizing the large demand, IIRS has started outreach program in basics of Remote Sensing, GIS and GPS for universities and institutions. EDUSAT (Educational Satellite) is the communication satellite built and launched by ISRO in 2004 exclusively for serving the educational sector to meet the demand for an interactive satellite based distance education system for the country. IIRS has used EDUSAT (shifted to INSAT 4 CR recently due to termination of services from EDUSAT) for its distance learning program to impart basic training in Remote Sensing, GIS and GPS, catering to the universities spread across India. The EDUSAT based training is following similar to e-learning method but has advantage of live interaction sessions between teacher and the students when the lecture is delivered using EDUSAT satellite communication. Because of its good quality reception the interactions are not constrained due to bandwidth problems of Internet. National Natural Resource Management System, Department of Space, Government of India, under Standing Committee in Training and Technology funded this unique program to conduct the basic training in Geoinformatics. IIRS conducts 6 weeks basic training course on "Remote Sensing, GIS and GPS" regularly since the year 2007. The course duration is spread over the period of 3 months beginning with the start of the academic year (1st semester) i.e., July to December every year, for university students. IIRS has utilized EDUSAT satellite for conducting 4 six weeks

Phillips Laboratory small satellite initiatives

Science.gov (United States)

Lutey, Mark K.; Imler, Thomas A.; Davis, Robert J.

1993-09-01

The Phillips Laboratory Space Experiments Directorate in conjunction with the Air Force Space Test Program (AF STP), Defense Advanced Research and Projects Agency (DARPA) and Strategic Defense Initiative Organization (SDIO), are managing five small satellite program initiatives: Lightweight Exo-Atmospheric Projectile (LEAP) sponsored by SDIO, Miniature Sensor Technology Integration (MSTI) sponsored by SDIO, Technology for Autonomous Operational Survivability (TAOS) sponsored by Phillips Laboratory, TechSat sponsored by SDIO, and the Advanced Technology Standard Satellite Bus (ATSSB) sponsored by DARPA. Each of these spacecraft fulfills a unique set of program requirements. These program requirements range from a short-lived `one-of-a-kind' mission to the robust multi- mission role. Because of these diverging requirements, each program is driven to use a different design philosophy. But regardless of their design, there is the underlying fact that small satellites do not always equate to small missions. These spacecraft with their use of or ability to insert new technologies provide more capabilities and services for their respective payloads which allows the expansion of their mission role. These varying program efforts culminate in an ATSSB spacecraft bus approach that will support moderate size payloads, up to 500 pounds, in a large set of orbits while satisfying the `cheaper, faster, better' method of doing business. This technical paper provides an overview of each of the five spacecraft, focusing on the objectives, payoffs, technologies demonstrated, and program status.

Estimating Typhoon Rainfall over Sea from SSM/I Satellite Data Using an Improved Genetic Programming

Science.gov (United States)

Yeh, K.; Wei, H.; Chen, L.; Liu, G.

2010-12-01

Estimating Typhoon Rainfall over Sea from SSM/I Satellite Data Using an Improved Genetic Programming Keh-Chia Yeha, Hsiao-Ping Weia,d, Li Chenb, and Gin-Rong Liuc a Department of Civil Engineering, National Chiao Tung University, Hsinchu, Taiwan, 300, R.O.C. b Department of Civil Engineering and Engineering Informatics, Chung Hua University, Hsinchu, Taiwan, 300, R.O.C. c Center for Space and Remote Sensing Research, National Central University, Tao-Yuan, Taiwan, 320, R.O.C. d National Science and Technology Center for Disaster Reduction, Taipei County, Taiwan, 231, R.O.C. Abstract This paper proposes an improved multi-run genetic programming (GP) and applies it to predict the rainfall using meteorological satellite data. GP is a well-known evolutionary programming and data mining method, used to automatically discover the complex relationships among nonlinear systems. The main advantage of GP is to optimize appropriate types of function and their associated coefficients simultaneously. This study makes an improvement to enhance escape ability from local optimums during the optimization procedure. The GP continuously runs several times by replacing the terminal nodes at the next run with the best solution at the current run. The current novel model improves GP, obtaining a highly nonlinear mathematical equation to estimate the rainfall. In the case study, this improved GP described above combining with SSM/I satellite data is employed to establish a suitable method for estimating rainfall at sea surface during typhoon periods. These estimated rainfalls are then verified with the data from four rainfall stations located at Peng-Jia-Yu, Don-Gji-Dao, Lan-Yu, and Green Island, which are four small islands around Taiwan. From the results, the improved GP can generate sophisticated and accurate nonlinear mathematical equation through two-run learning procedures which outperforms the traditional multiple linear regression, empirical equations and back-propagated network

Visibility Analysis of Domestic Satellites on Proposed Ground Sites for Optical Surveillance

Directory of Open Access Journals (Sweden)

Jung Hyun Jo1

2011-12-01

Full Text Available The objectives of this study are to analyze the satellite visibility at the randomly established ground sites, to determine the five optimal ground sites to perform the optical surveillance and tracking of domestic satellites, and to verify the acquisition of the optical observation time sufficient to maintain the precise ephemeris at optimal ground sites that have been already determined. In order to accomplish these objectives, we analyzed the visibility for sun-synchronous orbit satellites, low earth orbit satellites, middle earth orbit satellites and domestic satellites as well as the continuous visibility along with the fictitious satellite ground track, and calculate the effective visibility. For the analysis, we carried out a series of repetitive process using the satellite tool kit simulation software developed by Analytical Graphics Incorporated. The lighting states of the penumbra and direct sun were set as the key constraints of the optical observation. The minimum of the observation satellite elevation angle was set to be 20 degree, whereas the maximum of the sun elevation angle was set to be -10 degree which is within the range of the nautical twilight. To select the candidates for the optimal optical observation, the entire globe was divided into 84 sectors in a constant interval, the visibility characteristics of the individual sectors were analyzed, and 17 ground sites were arbitrarily selected and analyzed further. Finally, five optimal ground sites (Khurel Togoot Observatory, Assy-Turgen Observatory, Tubitak National Observatory, Bisdee Tier Optical Astronomy Observatory, and South Africa Astronomical Observatory were determined. The total observation period was decided as one year. To examine the seasonal variation, the simulation was performed for the period of three days or less with respect to spring, summer, fall and winter. In conclusion, we decided the optimal ground sites to perform the optical surveillance and tracking

Error Analysis of Satellite Precipitation-Driven Modeling of Flood Events in Complex Alpine Terrain

Directory of Open Access Journals (Sweden)

Yiwen Mei

2016-03-01

Full Text Available The error in satellite precipitation-driven complex terrain flood simulations is characterized in this study for eight different global satellite products and 128 flood events over the Eastern Italian Alps. The flood events are grouped according to two flood types: rain floods and flash floods. The satellite precipitation products and runoff simulations are evaluated based on systematic and random error metrics applied on the matched event pairs and basin-scale event properties (i.e., rainfall and runoff cumulative depth and time series shape. Overall, error characteristics exhibit dependency on the flood type. Generally, timing of the event precipitation mass center and dispersion of the time series derived from satellite precipitation exhibits good agreement with the reference; the cumulative depth is mostly underestimated. The study shows a dampening effect in both systematic and random error components of the satellite-driven hydrograph relative to the satellite-retrieved hyetograph. The systematic error in shape of the time series shows a significant dampening effect. The random error dampening effect is less pronounced for the flash flood events and the rain flood events with a high runoff coefficient. This event-based analysis of the satellite precipitation error propagation in flood modeling sheds light on the application of satellite precipitation in mountain flood hydrology.

Verifying Air Force Weather Passive Satellite Derived Cloud Analysis Products

Science.gov (United States)

Nobis, T. E.

2017-12-01

Air Force Weather (AFW) has developed an hourly World-Wide Merged Cloud Analysis (WWMCA) using imager data from 16 geostationary and polar-orbiting satellites. The analysis product contains information on cloud fraction, height, type and various optical properties including optical depth and integrated water path. All of these products are derived using a suite of algorithms which rely exclusively on passively sensed data from short, mid and long wave imager data. The system integrates satellites with a wide-range of capabilities, from the relatively simple two-channel OLS imager to the 16 channel ABI/AHI to create a seamless global analysis in real time. Over the last couple of years, AFW has started utilizing independent verification data from active sensed cloud measurements to better understand the performance limitations of the WWMCA. Sources utilized include space based lidars (CALIPSO, CATS) and radar (CloudSat) as well as ground based lidars from the Department of Energy ARM sites and several European cloud radars. This work will present findings from our efforts to compare active and passive sensed cloud information including comparison techniques/limitations as well as performance of the passive derived cloud information against the active.

Spectrum and power allocation in cognitive multi-beam satellite communications with flexible satellite payloads

Science.gov (United States)

Liu, Zhihui; Wang, Haitao; Dong, Tao; Yin, Jie; Zhang, Tingting; Guo, Hui; Li, Dequan

2018-02-01

In this paper, the cognitive multi-beam satellite system, i.e., two satellite networks coexist through underlay spectrum sharing, is studied, and the power and spectrum allocation method is employed for interference control and throughput maximization. Specifically, the multi-beam satellite with flexible payload reuses the authorized spectrum of the primary satellite, adjusting its transmission band as well as power for each beam to limit its interference on the primary satellite below the prescribed threshold and maximize its own achievable rate. This power and spectrum allocation problem is formulated as a mixed nonconvex programming. For effective solving, we first introduce the concept of signal to leakage plus noise ratio (SLNR) to decouple multiple transmit power variables in the both objective and constraint, and then propose a heuristic algorithm to assign spectrum sub-bands. After that, a stepwise plus slice-wise algorithm is proposed to implement the discrete power allocation. Finally, simulation results show that adopting cognitive technology can improve spectrum efficiency of the satellite communication.

Satellite stories: capturing professional experiences of academic health sciences librarians working in delocalized health sciences programs.

Science.gov (United States)

Phinney, Jackie; Horsman, Amanda Rose

2018-01-01

Health sciences training programs have progressively expanded onto satellite campuses, allowing students the opportunity to learn in communities away from an academic institution's main campus. This expansion has encouraged a new role for librarians to assume, in that a subset of health sciences librarians identify as "satellite librarians" who are permanently located at a distance from the main campus. Due to the unique nature of this role and lack of existing data on the topic, the authors investigated the experiences and perceptions of this unique group of information professionals. An electronic survey was distributed to health sciences librarians via two prominent North American email discussion lists. Questions addressed the librarians' demographics, feelings of social inclusion, technological support, autonomy, professional support, and more. Eighteen surveys were analyzed. While several respondents stated that they had positive working relationships with colleagues, many cited issues with technology, scheduling, and lack of consideration as barriers to feeling socially included at both the parent and local campuses. Social inclusion, policy creation, and collection management issues were subject to their unique situations and their colleagues' perceptions of their roles as satellite librarians. The results from this survey suggest that the role of the academic health sciences librarian at the satellite campus needs to be clearly communicated and defined. This, in turn, will enhance the experience for the librarian and provide better service to the client.

History of Satellite TV Broadcasting and Satellite Broadcasting Market in Turkey

Directory of Open Access Journals (Sweden)

Mihalis KUYUCU

2015-09-01

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

Differential Spatio-temporal Multiband Satellite Image Clustering using K-means Optimization With Reinforcement Programming

Directory of Open Access Journals (Sweden)

Irene Erlyn Wina Rachmawan

2015-06-01

Full Text Available Deforestration is one of the crucial issues in Indonesia because now Indonesia has world's highest deforestation rate. In other hand, multispectral image delivers a great source of data for studying spatial and temporal changeability of the environmental such as deforestration area. This research present differential image processing methods for detecting nature change of deforestration. Our differential image processing algorithms extract and indicating area automatically. The feature of our proposed idea produce extracted information from multiband satellite image and calculate the area of deforestration by years with calculating data using temporal dataset. Yet, multiband satellite image consists of big data size that were difficult to be handled for segmentation. Commonly, K- Means clustering is considered to be a powerfull clustering algorithm because of its ability to clustering big data. However K-Means has sensitivity of its first generated centroids, which could lead into a bad performance. In this paper we propose a new approach to optimize K-Means clustering using Reinforcement Programming in order to clustering multispectral image. We build a new mechanism for generating initial centroids by implementing exploration and exploitation knowledge from Reinforcement Programming. This optimization will lead a better result for K-means data cluster. We select multispectral image from Landsat 7 in past ten years in Medawai, Borneo, Indonesia, and apply two segmentation areas consist of deforestration land and forest field. We made series of experiments and compared the experimental results of K-means using Reinforcement Programming as optimizing initiate centroid and normal K-means without optimization process. Keywords: Deforestration, Multispectral images, landsat, automatic clustering, K-means.

Boomerang Satellites

Science.gov (United States)

Hesselbrock, Andrew; Minton, David A.

2017-10-01

We recently reported that the orbital architecture of the Martian environment allows for material in orbit around the planet to ``cycle'' between orbiting the planet as a ring, or as coherent satellites. Here we generalize our previous analysis to examine several factors that determine whether satellites accreting at the edge of planetary rings will cycle. In order for the orbiting material to cycle, tidal evolution must decrease the semi-major axis of any accreting satellites. In some systems, the density of the ring/satellite material, the surface mass density of the ring, the tidal parameters of the system, and the rotation rate of the primary body contribute to a competition between resonant ring torques and tidal dissipation that prevent this from occurring, either permanently or temporarily. Analyzing these criteria, we examine various bodies in our solar system (such as Saturn, Uranus, and Eris) to identify systems where cycling may occur. We find that a ring-satellite cycle may give rise to the current Uranian ring-satellite system, and suggest that Miranda may have formed from an early, more massive Uranian ring.

Satellite tracking of threatened species

Science.gov (United States)

Williams, M.; Lunsford, A.; Ellis, D.; Robinson, J.; Coronado, P.; Campbell, W.

1998-01-01

In 1990, a joint effort of two U.S. federal agencies, NASA Goddard Space Flight Center (GSFC) and the Patuxent Wildlife Research Center, began. We initially joined forces in a project that used satellite telemetry to discover the winter home of a tiny dwindling population of Siberian Cranes. Since then several projects have emerged, and a web site was created to follow some of these activities. This web site is called the Satellite Tracking of Threatened Species and its location is http://sdcd.gsfc.nasa.gov/ISTO/satellite_tracking. It describes the overall program, and links you to three subsections that describe the projects in more detail: Satellite Direct Readout, Birdtracks, and Birdworld.

Multi-Satellite Synergy for Aerosol Analysis in the Asian Monsoon Region

Science.gov (United States)

Ichoku, Charles; Petrenko, Maksym

2012-01-01

Atmospheric aerosols represent one of the greatest uncertainties in environmental and climate research, particularly in tropical monsoon regions such as the Southeast Asian regions, where significant contributions from a variety of aerosol sources and types is complicated by unstable atmospheric dynamics. Although aerosols are now routinely retrieved from multiple satellite Sensors, in trying to answer important science questions about aerosol distribution, properties, and impacts, researchers often rely on retrievals from only one or two sensors, thereby running the risk of incurring biases due to sensor/algorithm peculiarities. We are conducting detailed studies of aerosol retrieval uncertainties from various satellite sensors (including Terra-/ Aqua-MODIS, Terra-MISR, Aura-OMI, Parasol-POLDER, SeaWiFS, and Calipso-CALIOP), based on the collocation of these data products over AERONET and other important ground stations, within the online Multi-sensor Aerosol Products Sampling System (MAPSS) framework that was developed recently. Such analyses are aimed at developing a synthesis of results that can be utilized in building reliable unified aerosol information and climate data records from multiple satellite measurements. In this presentation, we will show preliminary results of. an integrated comparative uncertainly analysis of aerosol products from multiple satellite sensors, particularly focused on the Asian Monsoon region, along with some comparisons from the African Monsoon region.

Molecular analysis and genomic organization of major DNA satellites in banana (Musa spp.).

Science.gov (United States)

Čížková, Jana; Hřibová, Eva; Humplíková, Lenka; Christelová, Pavla; Suchánková, Pavla; Doležel, Jaroslav

2013-01-01

Satellite DNA sequences consist of tandemly arranged repetitive units up to thousands nucleotides long in head-to-tail orientation. The evolutionary processes by which satellites arise and evolve include unequal crossing over, gene conversion, transposition and extra chromosomal circular DNA formation. Large blocks of satellite DNA are often observed in heterochromatic regions of chromosomes and are a typical component of centromeric and telomeric regions. Satellite-rich loci may show specific banding patterns and facilitate chromosome identification and analysis of structural chromosome changes. Unlike many other genomes, nuclear genomes of banana (Musa spp.) are poor in satellite DNA and the information on this class of DNA remains limited. The banana cultivars are seed sterile clones originating mostly from natural intra-specific crosses within M. acuminata (A genome) and inter-specific crosses between M. acuminata and M. balbisiana (B genome). Previous studies revealed the closely related nature of the A and B genomes, including similarities in repetitive DNA. In this study we focused on two main banana DNA satellites, which were previously identified in silico. Their genomic organization and molecular diversity was analyzed in a set of nineteen Musa accessions, including representatives of A, B and S (M. schizocarpa) genomes and their inter-specific hybrids. The two DNA satellites showed a high level of sequence conservation within, and a high homology between Musa species. FISH with probes for the satellite DNA sequences, rRNA genes and a single-copy BAC clone 2G17 resulted in characteristic chromosome banding patterns in M. acuminata and M. balbisiana which may aid in determining genomic constitution in interspecific hybrids. In addition to improving the knowledge on Musa satellite DNA, our study increases the number of cytogenetic markers and the number of individual chromosomes, which can be identified in Musa.

Comparison of ORSAT and SCARAB Reentry Analysis Tools for a Generic Satellite Test Case

Science.gov (United States)

Kelley, Robert L.; Hill, Nicole M.; Rochelle, W. C.; Johnson, Nicholas L.; Lips, T.

2010-01-01

Reentry analysis is essential to understanding the consequences of the full life cycle of a spacecraft. Since reentry is a key factor in spacecraft development, NASA and ESA have separately developed tools to assess the survivability of objects during reentry. Criteria such as debris casualty area and impact energy are particularly important to understanding the risks posed to people on Earth. Therefore, NASA and ESA have undertaken a series of comparison studies of their respective reentry codes for verification and improvements in accuracy. The NASA Object Reentry Survival Analysis Tool (ORSAT) and the ESA Spacecraft Atmospheric Reentry and Aerothermal Breakup (SCARAB) reentry analysis tools serve as standard codes for reentry survivability assessment of satellites. These programs predict whether an object will demise during reentry and calculate the debris casualty area of objects determined to survive, establishing the reentry risk posed to the Earth's population by surviving debris. A series of test cases have been studied for comparison and the most recent uses "Testsat," a conceptual satellite composed of generic parts, defined to use numerous simple shapes and various materials for a better comparison of the predictions of these two codes. This study is an improvement on the others in this series because of increased consistency in modeling techniques and variables. The overall comparison demonstrated that the two codes arrive at similar results. Either most objects modeled resulted in close agreement between the two codes, or if the difference was significant, the variance could be explained as a case of semantics in the model definitions. This paper presents the main results of ORSAT and SCARAB for the Testsat case and discusses the sources of any discovered differences. Discussion of the results of previous comparisons is made for a summary of differences between the codes and lessons learned from this series of tests.

History of Satellite Orbit Determination at NSWCDD

Science.gov (United States)

2018-01-31

meeting of the Satellite Division of ION, Palm Springs, CA., 12–15 Sep 1995. Hughey, Raymond H., Jr., “ History of Mathematics and Computing Technology ...TR-17/229 HISTORY OF SATELLITE ORBIT DETERMINATION AT NSWCDD BY EVERETT R. SWIFT WARFARE SYSTEMS ENGINEERING AND INTEGRATION...AND SUBTITLE History of Satellite Orbit Determination at NSWCDD 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER

Remote sensing by satellite - Technical and operational implications for international cooperation

Science.gov (United States)

Doyle, S. E.

1976-01-01

International cooperation in the U.S. Space Program is discussed and related to the NASA program for remote sensing of the earth. Satellite remote sensing techniques are considered along with the selection of the best sensors and wavelength bands. The technology of remote sensing satellites is considered with emphasis on the Landsat system configuration. Future aspects of remote sensing satellites are considered.

Satellite Geomagnetism

DEFF Research Database (Denmark)

Olsen, Nils; Stolle, Claudia

2012-01-01

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....... 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...... 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....

Use of the Comprehensive Inversion method for Swarm satellite data analysis

DEFF Research Database (Denmark)

Sabaka, T. J.; Tøffner-Clausen, Lars; Olsen, Nils

2013-01-01

An advanced algorithm, known as the “Comprehensive Inversion” (CI), is presented for the analysis of Swarm measurements to generate a consistent set of Level-2 data products to be delivered by the Swarm “Satellite Constellation Application and Research Facility” (SCARF) to the European Space Agency...

South Florida Everglades: satellite image map

Science.gov (United States)

Jones, John W.; Thomas, Jean-Claude; Desmond, G.B.

2001-01-01

These satellite image maps are one product of the USGS Land Characteristics from Remote Sensing project, funded through the USGS Place-Based Studies Program (http://access.usgs.gov/) with support from the Everglades National Park (http://www.nps.gov/ever/). The objective of this project is to develop and apply innovative remote sensing and geographic information system techniques to map the distribution of vegetation, vegetation characteristics, and related hydrologic variables through space and over time. The mapping and description of vegetation characteristics and their variations are necessary to accurately simulate surface hydrology and other surface processes in South Florida and to monitor land surface changes. As part of this research, data from many airborne and satellite imaging systems have been georeferenced and processed to facilitate data fusion and analysis. These image maps were created using image fusion techniques developed as part of this project.

Prediction of Communication Outage Period between Satellite and Earth station Due to Sun Interference

Directory of Open Access Journals (Sweden)

Yongjun Song

2010-03-01

Full Text Available We developed a computer program to predict solar interference period. To calculate Sun‘s position, we used DE406 ephemerides and Earth ellipsoid model. The Sun‘s position error is smaller than 10arcsec. For the verification of the calculation, we used TU media ground station on Seongsu-dong, and MBSAT geostationary communication satellite. We analysis errors, due to satellite perturbation and antenna align. The time error due to antenna align has -35 to +16 seconds at 0.1 degree, and -27 to +41 seconds at 0.25 degree. The time errors derived by satellite perturbation has 30 to 60 seconds.

Paving the Way for Small Satellite Access to Orbit: Cyclops' Deployment of SpinSat, the Largest Satellite Ever Deployed from the International Space Station

Science.gov (United States)

Hershey, Matthew P.; Newswander, Daniel R.; Smith, James P.; Lamb, Craig R.; Ballard, Perry G.

2015-01-01

The Space Station Integrated Kinetic Launcher for Orbital Payload Systems (SSIKLOPS), known as "Cyclops" to the International Space Station (ISS) community, successfully deployed the largest satellite ever (SpinSat) from the ISS on November 28, 2014. Cyclops, a collaboration between the NASA ISS Program, NASA Johnson Space Center Engineering, and Department of Defense Space Test Program (DoD STP) communities, is a dedicated 10-100 kg class ISS small satellite deployment system. This paper will showcase the successful deployment of SpinSat from the ISS. It will also outline the concept of operations, interfaces, requirements, and processes for satellites to utilize the Cyclops satellite deployment system.

Proceedings of the 2016 National Toxicology Program Satellite Symposium.

Science.gov (United States)

Elmore, Susan A; Chen, Vivian S; Hayes-Bouknight, Schantel; Hoane, Jessica S; Janardhan, Kyathanahalli; Kooistra, Linda H; Nolte, Thomas; Szabo, Kathleen A; Willson, Gabrielle A; Wolf, Jeffrey C; Malarkey, David E

2017-01-01

The 2016 annual National Toxicology Program Satellite Symposium, entitled "Pathology Potpourri" was held in San Diego, CA, at the Society of Toxicologic Pathology's (STP) 35th annual meeting. The goal of this symposium was to present and discuss challenging diagnostic pathology and/or nomenclature issues. This article presents summaries of the speakers' talks, along with select images that were used by the audience for voting and discussion. Some lesions and topics covered during the symposium included malignant glioma and histiocytic sarcoma in the rodent brain; a new statistical method designed for histopathology data evaluation; uterine stromal/glandular polyp in a rat; malignant plasma cell tumor in a mouse brain; Schwann cell proliferative lesions in rat hearts; axillary schwannoma in a cat; necrosis and granulomatous inflammation in a rat brain; adenoma/carcinoma in a rat adrenal gland; hepatocyte maturation defect and liver/spleen hematopoietic defects in an embryonic mouse; distinguishing malignant glioma, malignant mixed glioma, and malignant oligodendroglioma in the rat; comparison of mammary gland whole mounts and histopathology from mice; and discussion of the International Harmonization of Nomenclature and Diagnostic Criteria collaborations.

A Covert Disruptive Technology: Test and Development of the Corona Satellite

Science.gov (United States)

Peebles, Curtis

2008-01-01

The launching by the Soviet Union of the Sputnik satellite in 19457 was an impetuous to the United States. The Intercontinental ballistic Missile (ICBM) that launched the Earth's first satellite, could have been armed with a nuclear warhead, that could destroy an American city. The primary intelligence requirement that the US had was to determine the actual size of the Soviet missile program. To this end, a covert, high-risk photoreconnaissance satellite was developed. The code name of this program was "Corona." This article describes the trials and eventual successes of the Corona program.

Satellite broadcasting - The European experience and perspective

Science.gov (United States)

Watson, Alan

1991-11-01

The use of satellites is considered as a means for developing a European transnational broadcasting system with attention given to the control of technology. A tension is described between maintaining technology as the property of one nation when the DBSs are developed for multinational program broadcasting. The simultaneous development of satellite systems is theorized to lead eventually to a single merged program for a particular nation, and the effect is considered of the regulation of cross-holding and cross-selling systems by investors.

The Direct Satellite Connection: Definitions and Prospects.

Science.gov (United States)

Wigand, Rolf T.

1980-01-01

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

Prototype Design and Mission Analysis for a Small Satellite Exploiting Environmental Disturbances for Attitude Stabilization

Science.gov (United States)

2016-03-01

AND MISSION ANALYSIS FOR A SMALL SATELLITE EXPLOITING ENVIRONMENTAL DISTURBANCES FOR ATTITUDE STABILIZATION by Halis C. Polat March 2016...FOR A SMALL SATELLITE EXPLOITING ENVIRONMENTAL DISTURBANCES FOR ATTITUDE STABILIZATION 5. FUNDING NUMBERS 6. AUTHOR(S) Halis C. Polat 7...need a robust and accurate attitude control system. Due to the mass- and volume-constrained design environment of CubeSat, conventional methods are

Measuring Relativistic effects in the field of the Earth with Laser Ranged Satellites and the LARASE research program

Science.gov (United States)

Lucchesi, David; Anselmo, Luciano; Bassan, Massimo; Magnafico, Carmelo; Pardini, Carmen; Peron, Roberto; Pucacco, Giuseppe; Stanga, Ruggero; Visco, Massimo

2017-04-01

The main goal of the LARASE (LAser RAnged Satellites Experiment) research program is to obtain refined tests of Einstein's theory of General Relativity (GR) by means of very precise measurements of the round-trip time among a number of ground stations of the International Laser Ranging Service (ILRS) network and a set of geodetic satellites. These measurements are guaranteed by means of the powerful and precise Satellite Laser Ranging (SLR) technique. In particular, a big effort of LARASE is dedicated to improve the dynamical models of the LAGEOS, LAGEOS II and LARES satellites, with the objective to obtain a more precise and accurate determination of their orbit. These activities contribute to reach a final error budget that should be robust and reliable in the evaluation of the main systematic errors sources that come to play a major role in masking the relativistic precession on the orbit of these laser-ranged satellites. These error sources may be of gravitational and non-gravitational origin. It is important to stress that a more accurate and precise orbit determination, based on more reliable dynamical models, represents a fundamental prerequisite in order to reach a sub-mm precision in the root-mean-square of the SLR range residuals and, consequently, to gather benefits in the fields of geophysics and space geodesy, such as stations coordinates knowledge, geocenter determination and the realization of the Earth's reference frame. The results reached over the last year will be presented in terms of the improvements achieved in the dynamical model, in the orbit determination and, finally, in the measurement of the relativistic precessions that act on the orbit of the satellites considered.

Modeling and Performance Analysis of 10 Gbps Inter-satellite Optical Wireless Communication Link

Science.gov (United States)

Singh, Mehtab

2017-12-01

Free-space optical (FSO) communication has the advantages of two of the most predominant data transmission technologies - optical fiber communication and wireless communication. Most of the technical aspects of FSO are similar to that of optical fiber communication, with major difference in the information signal propagation medium which is free space in case of FSO rather than silica glass in optical fiber communication. One of the most important applications of FSO is inter-satellite optical wireless communication (IsOWC) links which will be deployed in the future in space. The IsOWC links have many advantages over the previously existing microwave satellite communication technologies such as higher bandwidth, lower power consumption, low cost of implementation, light size, and weight. In this paper, modeling and performance analysis of a 10-Gbps inter-satellite communication link with two satellites separated at a distance of 1,200 km has been done using OPTISYSTEM simulation software. Performance has been analyzed on the basis of quality factor, signal to noise ratio (SNR), and total power of the received signal.

GOES-R: Satellite Insight

Science.gov (United States)

Fitzpatrick, Austin J.; Leon, Nancy J.; Novati, Alexander; Lincoln, Laura K.; Fisher, Diane K.

2012-01-01

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.

Capacity Model and Constraints Analysis for Integrated Remote Wireless Sensor and Satellite Network in Emergency Scenarios

Science.gov (United States)

Zhang, Wei; Zhang, Gengxin; Dong, Feihong; Xie, Zhidong; Bian, Dongming

2015-01-01

This article investigates the capacity problem of an integrated remote wireless sensor and satellite network (IWSSN) in emergency scenarios. We formulate a general model to evaluate the remote sensor and satellite network capacity. Compared to most existing works for ground networks, the proposed model is time varying and space oriented. To capture the characteristics of a practical network, we sift through major capacity-impacting constraints and analyze the influence of these constraints. Specifically, we combine the geometric satellite orbit model and satellite tool kit (STK) engineering software to quantify the trends of the capacity constraints. Our objective in analyzing these trends is to provide insights and design guidelines for optimizing the integrated remote wireless sensor and satellite network schedules. Simulation results validate the theoretical analysis of capacity trends and show the optimization opportunities of the IWSSN. PMID:26593919

Capacity Model and Constraints Analysis for Integrated Remote Wireless Sensor and Satellite Network in Emergency Scenarios.

Science.gov (United States)

Zhang, Wei; Zhang, Gengxin; Dong, Feihong; Xie, Zhidong; Bian, Dongming

2015-11-17

This article investigates the capacity problem of an integrated remote wireless sensor and satellite network (IWSSN) in emergency scenarios. We formulate a general model to evaluate the remote sensor and satellite network capacity. Compared to most existing works for ground networks, the proposed model is time varying and space oriented. To capture the characteristics of a practical network, we sift through major capacity-impacting constraints and analyze the influence of these constraints. Specifically, we combine the geometric satellite orbit model and satellite tool kit (STK) engineering software to quantify the trends of the capacity constraints. Our objective in analyzing these trends is to provide insights and design guidelines for optimizing the integrated remote wireless sensor and satellite network schedules. Simulation results validate the theoretical analysis of capacity trends and show the optimization opportunities of the IWSSN.

Weather Satellite Pictures and How to Obtain Them.

Science.gov (United States)

Petit, Noel J.; Johnson, Philip

1982-01-01

An introduction to satellite meteorology is presented to promote use of live weather satellite photographs in the classroom. Topics addressed include weather satellites, how they work, earth emissions, satellite photography, satellite image analysis, obtaining satellite pictures, and future considerations. Includes sources for materials to…

Satellite Power Systems (SPS) concept definition study, exhibit C. Volume 2, part 2: System engineering, cost and programmatics

Science.gov (United States)

Hanley, G. M.

1979-01-01

Volume 2, Part 2, of a seven volume Satellite Power Systems (SPS) report is presented. Part 2 covers cost and programmatics and is divided into four sections. The first section gives illustrations of the SPS reference satellite and rectenna concept, and an overall scenario for SPS space transportation involvement. The second section presents SPS program plans for the implementation of PHASE C/D activities. These plans describe SPS program schedules and networks, critical items of systems evolution/technology development, and the natural resources analysis. The fourth section presents summary comments on the methods and rationale followed in arriving at the results documented. Suggestions are also provided in those areas where further analysis or evaluation will enhance SPS cost and programmatic definitions.

A multifaceted approach to understanding dynamic urban processes: satellites, surveys, and censuses.

Science.gov (United States)

Jones, B.; Balk, D.; Montgomery, M.; Liu, Z.

2014-12-01

Urbanization will arguably be the most significant demographic trend of the 21st century, particularly in fast-growing regions of the developing world. Characterizing urbanization in a spatial context, however, is a difficult task given only the moderate resolution data provided by traditional sources of demographic data (i.e., censuses and surveys). Using a sample of five world "mega-cities" we demonstrate how new satellite data products and new analysis of existing satellite data, when combined with new applications of census and survey microdata, can reveal more about cities and urbanization in combination than either data type can by itself. In addition to the partially modelled Global Urban-Rural Mapping Project (GRUMP) urban extents we consider four sources of remotely sensed data that can be used to estimate urban extents; the NOAA Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) intercallibrated nighttime lights time series data, the newer NOAA Visible Infrared Imager Radiometer Suite (VIIRS) nighttime lights data, the German Aerospace Center (DLR) radar satellite data, and Dense Sampling Method (DSM) analysis of the NASA scatterometer data. Demographic data come from national censuses and/or georeferenced survey data from the Demographic & Health Survey (DHS) program. We overlay demographic and remotely sensed data (e.g., Figs 1, 2) to address two questions; (1) how well do satellite derived measures of urban intensity correlate with demographic measures, and (2) how well are temporal changes in the data correlated. Using spatial regression techniques, we then estimate statistical relationships (controlling for influences such as elevation, coastal proximity, and economic development) between the remotely sensed and demographic data and test the ability of each to predict the other. Satellite derived imagery help us to better understand the evolution of the built environment and urban form, while the underlying demographic

Transient SEU characterization of analog IC's for ESA's satellite

International Nuclear Information System (INIS)

Harboe-Soerensen, R.; Van Dooren, J.; Guerre, F.X.; Constans, H.; Berger, G.; Hajdas, W.

1999-01-01

Data analysis of four self switch-off power supply events in the SOHO satellite pointed strongly in the direction of being Cosmic Ray or Proton induced. Further analysis of the relevant power supply schematics identified a number of analog IC's capable of causing or contributing to such events. This paper concentrates on the testing aspects of these analog IC's and presents the results of a Single Event Effects (SEEs) test program. Ground testing, simulating the flight conditions, were carried out at both heavy ion and proton accelerators. (authors)

Analysis of Specular Reflections Off Geostationary Satellites

Science.gov (United States)

Jolley, A.

2016-09-01

Many photometric studies of artificial satellites have attempted to define procedures that minimise the size of datasets required to infer information about satellites. However, it is unclear whether deliberately limiting the size of datasets significantly reduces the potential for information to be derived from them. In 2013 an experiment was conducted using a 14 inch Celestron CG-14 telescope to gain multiple night-long, high temporal resolution datasets of six geostationary satellites [1]. This experiment produced evidence of complex variations in the spectral energy distribution (SED) of reflections off satellite surface materials, particularly during specular reflections. Importantly, specific features relating to the SED variations could only be detected with high temporal resolution data. An update is provided regarding the nature of SED and colour variations during specular reflections, including how some of the variables involved contribute to these variations. Results show that care must be taken when comparing observed spectra to a spectral library for the purpose of material identification; a spectral library that uses wavelength as the only variable will be unable to capture changes that occur to a material's reflected spectra with changing illumination and observation geometry. Conversely, colour variations with changing illumination and observation geometry might provide an alternative means of determining material types.

Ecosystem Analysis Program

International Nuclear Information System (INIS)

Burgess, R.L.

1978-01-01

Progress is reported on the following research programs: analysis and modeling of ecosystems; EDFB/IBP data center; biome analysis studies; land/water interaction studies; and computer programs for development of models

Commercial satellite broadcasting for Europe

Science.gov (United States)

Forrest, J. R.

1988-12-01

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.

Recent Korean R&D in Satellite Communications

Science.gov (United States)

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

Status of Satellite Television Broadcast Programs Implementation in ...

African Journals Online (AJOL)

70.4 % of teachers agreed that the depth was up to the level of the students. Relevance ... importance of ICT in education. Among others ... advantages of satellite plasma television. ...... Standard English, could understand the contextual ...

Global, Persistent, Real-time Multi-sensor Automated Satellite Image Analysis and Crop Forecasting in Commercial Cloud

Science.gov (United States)

Brumby, S. P.; Warren, M. S.; Keisler, R.; Chartrand, R.; Skillman, S.; Franco, E.; Kontgis, C.; Moody, D.; Kelton, T.; Mathis, M.

2016-12-01

Cloud computing, combined with recent advances in machine learning for computer vision, is enabling understanding of the world at a scale and at a level of space and time granularity never before feasible. Multi-decadal Earth remote sensing datasets at the petabyte scale (8×10^15 bits) are now available in commercial cloud, and new satellite constellations will generate daily global coverage at a few meters per pixel. Public and commercial satellite observations now provide a wide range of sensor modalities, from traditional visible/infrared to dual-polarity synthetic aperture radar (SAR). This provides the opportunity to build a continuously updated map of the world supporting the academic community and decision-makers in government, finanace and industry. We report on work demonstrating country-scale agricultural forecasting, and global-scale land cover/land, use mapping using a range of public and commercial satellite imagery. We describe processing over a petabyte of compressed raw data from 2.8 quadrillion pixels (2.8 petapixels) acquired by the US Landsat and MODIS programs over the past 40 years. Using commodity cloud computing resources, we convert the imagery to a calibrated, georeferenced, multiresolution tiled format suited for machine-learning analysis. We believe ours is the first application to process, in less than a day, on generally available resources, over a petabyte of scientific image data. We report on work combining this imagery with time-series SAR collected by ESA Sentinel 1. We report on work using this reprocessed dataset for experiments demonstrating country-scale food production monitoring, an indicator for famine early warning. We apply remote sensing science and machine learning algorithms to detect and classify agricultural crops and then estimate crop yields and detect threats to food security (e.g., flooding, drought). The software platform and analysis methodology also support monitoring water resources, forests and other general

Topography and Data Mining Based Methods for Improving Satellite Precipitation in Mountainous Areas of China

Directory of Open Access Journals (Sweden)

Ting Xia

2015-07-01

Full Text Available Topography is a significant factor influencing the spatial distribution of precipitation. This study developed a new methodology to evaluate and calibrate the Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis (TMPA products by merging geographic and topographic information. In the proposed method, firstly, the consistency rule was introduced to evaluate the fitness of satellite rainfall with measurements on the grids with and without ground gauges. Secondly, in order to improve the consistency rate of satellite rainfall, genetic programming was introduced to mine the relationship between the gauge rainfall and location, elevation and TMPA rainfall. The proof experiment and analysis for the mean annual satellite precipitation from 2001–2012, 3B43 (V7 of TMPA rainfall product, was carried out in eight mountainous areas of China. The result shows that the proposed method is significant and efficient both for the assessment and improvement of satellite precipitation. It is found that the satellite rainfall consistency rates in the gauged and ungauged grids are different in the study area. In addition, the mined correlation of location-elevation-TMPA rainfall can noticeably improve the satellite precipitation, both in the context of the new criterion of the consistency rate and the existing criteria such as Bias and RMSD. The proposed method is also efficient for correcting the monthly and mean monthly rainfall of 3B43 and 3B42RT.

Earth Observatory Satellite system definition study. Report 4: Low cost management approach and recommendations

Science.gov (United States)

1974-01-01

An analysis of low cost management approaches for the development of the Earth Observatory Satellite (EOS) is presented. The factors of the program which tend to increase costs are identified. The NASA/Industry interface is stressed to show how the interface can be improved to produce reduced program costs. Techniques and examples of cost reduction which can be applied to the EOS program are tabulated. Specific recommendations for actions to be taken to reduce costs in prescribed areas are submitted.

ESA's satellite communications programme

Science.gov (United States)

Bartholome, P.

1985-02-01

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.

Landsat—Earth observation satellites

Science.gov (United States)

,

2015-11-25

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.

Space industrialization - Education. [via communication satellites

Science.gov (United States)

Joels, K. M.

1978-01-01

The components of an educational system based on, and perhaps enhanced by, space industrialization communications technology are considered. Satellite technology has introduced a synoptic distribution system for various transmittable educational media. The cost of communications satellite distribution for educational programming has been high. It has, therefore, been proposed to utilize Space Shuttle related technology and Large Space Structures (LSS) to construct a system with a quantum advancement in communication capability and a quantum reduction in user cost. LSS for communications purposes have three basic advantages for both developed and emerging nations, including the ability to distribute signals over wide geographic areas, the reduced cost of satellite communications systems versus installation of land based systems, and the ability of a communication satellite system to create instant educational networks.

Development of Japanese Earth Resources Satellite-1 (JERS-1; FUYO-1) and it's operational results

Science.gov (United States)

1993-03-01

Various aspects of development progress from the policy decision to the launch and early orbit phase operation of the JERS-l (Japanese Earth Resources Satellite-l) are presented. The items presented are as follows: the fundamental development policy, related organizations, and the system for the development; the master schedule and the progress of the development; the outline of JERS-l including its missions, the structure and characteristics of the system, and the operation plan; satellite mission and the system design analyses; the system development, including that of subsystems and components, production and test of the system development model, the integration and test of the system PFM (Proto-Flight Model), and the modification and post-modification test of the PFM; interfaces with other programs; program control; satellite operation in the launch and early orbit operation phase and the analysis and evaluation of the operation results; and the initial examination on on-orbit failures.

The Advanced Communications Technology Satellite (ACTS) capabilities for serving science

Science.gov (United States)

Meyer, Thomas R.

1990-01-01

Results of research on potential science applications of the NASA Advanced Communications Technology Satellite (ACTS) are presented. Discussed here are: (1) general research on communications related issues; (2) a survey of science-related activities and programs in the local area; (3) interviews of selected scientists and associated telecommunications support personnel whose projects have communications requirements; (4) analysis of linkages between ACTS functionality and science user communications activities and modes of operation; and (5) an analysis of survey results and the projection of conclusions to a national scale.

German telecommunications satellite (Deutscher fernmelde satellit) (DFS-1 and -2)

Science.gov (United States)

Hiendlmeier, G.; Schmeller, H.

1991-01-01

The German Telecommunications Satellite (DFS) Program is to provide telecommunications service for high data rate transmission of text and video data to the Federal Republic of Germany within the 11-14 GHz and 20-30 GHz bands. The space segment of this program is composed of three satellites, DFS-1, DFS-2, and DFS-3, which will be located at 23.5 degrees E longitude of the geostationary orbit. The DFS will be launched from the Center Spatial Guyanis in French Giana on an Ariane launch vehicle. The mission follows the typical injection sequence: parking orbit, transfer orbit, and earth orbit. Attitude maneuvers will be performed to orient the spacecraft prior to Apogee Kick Motor (AKM) firing. After AKM firing, drift phase orbital and attitude maneuvers will be performed to place the spacecraft in its final geostationary position. The Deep Space Network (DSN) will support the transfer and drift orbit mission phases. Information is presented in tabular form for the following areas: DSN support, compatibility testing, frequency assignments, telemetry, command, and tracking support responsibilities.

Performance Analysis of Space Information Networks with Backbone Satellite Relaying for Vehicular Networks

Directory of Open Access Journals (Sweden)

Jian Jiao

2017-01-01

Full Text Available Space Information Network (SIN with backbone satellites relaying for vehicular network (VN communications is regarded as an effective strategy to provide diverse vehicular services in a seamless, efficient, and cost-effective manner in rural areas and highways. In this paper, we investigate the performance of SIN return channel cooperative communications via an amplify-and-forward (AF backbone satellite relaying for VN communications, where we assume that both of the source-destination and relay-destination links undergo Shadowed-Rician fading and the source-relay link follows Rician fading, respectively. In this SIN-assisted VN communication scenario, we first obtain the approximate statistical distributions of the equivalent end-to-end signal-to-noise ratio (SNR of the system. Then, we derive the closed-form expressions to efficiently evaluate the average symbol error rate (ASER of the system. Furthermore, the ASER expressions are taking into account the effect of satellite perturbation of the backbone relaying satellite, which reveal the accumulated error of the antenna pointing error. Finally, simulation results are provided to verify the accuracy of our theoretical analysis and show the impact of various parameters on the system performance.

Characterising volcanic cycles at Soufriere Hills Volcano, Montserrat: Time series analysis of multi-parameter satellite data

Science.gov (United States)

Flower, Verity J. B.; Carn, Simon A.

2015-10-01

The identification of cyclic volcanic activity can elucidate underlying eruption dynamics and aid volcanic hazard mitigation. Whilst satellite datasets are often analysed individually, here we exploit the multi-platform NASA A-Train satellite constellation to cross-correlate cyclical signals identified using complementary measurement techniques at Soufriere Hills Volcano (SHV), Montserrat. In this paper we present a Multi-taper (MTM) Fast Fourier Transform (FFT) analysis of coincident SO2 and thermal infrared (TIR) satellite measurements at SHV facilitating the identification of cyclical volcanic behaviour. These measurements were collected by the Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS) (respectively) in the A-Train. We identify a correlating cycle in both the OMI and MODIS data (54-58 days), with this multi-week feature attributable to episodes of dome growth. The 50 day cycles were also identified in ground-based SO2 data at SHV, confirming the validity of our analysis and further corroborating the presence of this cycle at the volcano. In addition a 12 day cycle was identified in the OMI data, previously attributed to variable lava effusion rates on shorter timescales. OMI data also display a one week (7-8 days) cycle attributable to cyclical variations in viewing angle resulting from the orbital characteristics of the Aura satellite. Longer period cycles possibly relating to magma intrusion were identified in the OMI record (102-, 121-, and 159 days); in addition to a 238-day cycle identified in the MODIS data corresponding to periodic destabilisation of the lava dome. Through the analysis of reconstructions generated from cycles identified in the OMI and MODIS data, periods of unrest were identified, including the major dome collapse of 20th May 2006 and significant explosive event of 3rd January 2009. Our analysis confirms the potential for identification of cyclical volcanic activity through combined

Methodology for the comparative assessment of the Satellite Power System (SPS) and alternative technologies

Energy Technology Data Exchange (ETDEWEB)

Wolsko, T.; Buehring, W.; Cirillo, R.; Gasper, J.; Habegger, L.; Hub, K.; Newsom, D.; Samsa, M.; Stenehjem, E.; Whitfield, R.

1980-01-01

A description of the initial methodology for the Comparative Assessment of the Satellite Power System Concept Development and Evaluation Program of NASA and DOE is presented. Included are study objectives, issue identification, units of measurement, methods, and data bases. The energy systems concerned are the satellite power system, several coal technologies, geothermal energy, fission, fusion, terrestrial solar systems, and ocean thermal energy conversion. Guidelines are suggested for the characterization of these systems, side-by-side analysis, alternative futures analysis, and integration and aggregation of data. The bulk of this report is a description of the methods for assessing the technical, economic, environmental, societal, and institutional issues surrounding the development of the selected energy technologies.

Sediment Plumes Resulting from the Port of Miami Dredging: Analysis and Interpretation Using Satellite Data and Long Term Monitoring Programs

Science.gov (United States)

Barnes, B. B.; Hu, C.; Kovach, C.; Silverstein, R. N.

2016-02-01

From November 2013 through mid-2015, large turbidity plumes were observed offshore the Port of Miami (Florida, USA), likely associated with a project to deepen and widen the Miami Harbor channels. Using data from local monitoring programs, however, it is difficult to estimate the size, duration, extent, and severity (relative to natural turbidity events) of these plumes. In contrast, satellite observing systems offer a platform from which these plumes can be monitored and placed in historical context. As such, turbidity plumes captured by MODIS (Aqua) and Landsat 8 reflectance data were manually outlined. For MODIS, these delineations were refined using reflectance anomaly thresholds, determined from pre-dredging data. Long term records of local environmental conditions were used to account for conditions (e.g., wind speed, tidal stage) for which elevated reflectance data might be expected in the absence of dredging. The spatial extent of turbidity plumes observed in the Port of Miami region during the dredging period ranged from 127 and 228 km2, at least 5 times that immediately prior to dredging. The frequency of observed plumes in satellite imagery increased from 23% to 84% after dredging began, while temporal differences in plume location, severity, and size were also observed. Turbidity plumes may have large adverse effects on coral communities, and this region is home to many species of coral (including some considered threatened by the US Endangered Species Act). Indeed, over 11 km2 of coral area was affected by these plumes, with some locations within plume delineations on nearly 40% of images. The approaches developed in this work, in particular the focus on historical norms after considering all perturbation factors, may be included in monitoring and assessment of this and future dredging activities, especially where fragile marine ecosystems may potentially be impacted.

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

Science.gov (United States)

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

Fibromodulin: a master regulator of myostatin controlling progression of satellite cells through a myogenic program.

Science.gov (United States)

Lee, Eun Ju; Jan, Arif Tasleem; Baig, Mohammad Hassan; Ashraf, Jalaluddin Mohammad; Nahm, Sang-Soep; Kim, Yong-Woon; Park, So-Young; Choi, Inho

2016-08-01

Differentiation of muscle satellite cells (MSCs) involves interaction of the proteins present in the extracellular matrix (ECM) with MSCs to regulate their activity, and therefore phenotype. Herein, we report fibromodulin (FMOD), a member of the proteoglycan family participating in the assembly of ECM, as a novel regulator of myostatin (MSTN) during myoblast differentiation. In addition to having a pronounced effect on the expression of myogenic marker genes [myogenin (MYOG) and myosin light chain 2 (MYL2)], FMOD was found to maintain the transcriptional activity of MSTN Moreover, coimmunoprecipitation and in silico studies performed to investigate the interaction of FMOD helped confirm that it antagonizes MSTN function by distorting its folding and preventing its binding to activin receptor type IIB. Furthermore, in vivo studies revealed that FMOD plays an active role in healing by increasing satellite cell recruitment to sites of injury. Together, these findings disclose a hitherto unrecognized regulatory role for FMOD in MSCs and highlight new mechanisms whereby FMOD circumvents the inhibitory effects of MSTN and triggers myoblast differentiation. These findings offer a basis for the design of novel MSTN inhibitors that promote muscle regeneration after injury or for the development of pharmaceutical agents for the treatment of different muscle atrophies.-Lee, E. J., Jan, A. T., Baig, M. H., Ashraf, J. M., Nahm, S.-S., Kim, Y.-W., Park, S.-Y., Choi, I. Fibromodulin: a master regulator of myostatin controlling progression of satellite cells through a myogenic program. © FASEB.

Small Explorer project: Submillimeter Wave Astronomy Satellite (SWAS). Mission operations and data analysis plan

Science.gov (United States)

Melnick, Gary J.

1990-01-01

The Mission Operations and Data Analysis Plan is presented for the Submillimeter Wave Astronomy Satellite (SWAS) Project. It defines organizational responsibilities, discusses target selection and navigation, specifies instrument command and data requirements, defines data reduction and analysis hardware and software requirements, and discusses mission operations center staffing requirements.

Small Satellite Mechanical Design Experience

OpenAIRE

Meyers, Stewart

1993-01-01

The design approach used and the experience gained in the building of four small satellite payloads is explained. Specific recommendations are made and the lessons learned on the SAMPEX program are detailed.

An analysis of Jupiter data from the RAE-1 satellite

Science.gov (United States)

Carr, T. D.

1974-01-01

The analysis of Radio Astronomy Explorer Satellite data are presented. Radio bursts from Jupiter are reported in the frequency range 4700 KHz to 45 KHz. Strong correlations with lo were found at 4700, 3930, and 2200 KHz, while an equally strong Europa effect was observed at 1300, 900, and 700 KHz. Histograms indicating the relative probability and the successful identification of Jupiter activity were plotted, using automatic computer and visual search techniques.

An introduction to optimal satellite range scheduling

CERN Document Server

Vázquez Álvarez, Antonio José

2015-01-01

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, ...

Satellite provided customer promises services, a forecast of potential domestic demand through the year 2000. Volume 4: Sensitivity analysis

Science.gov (United States)

Kratochvil, D.; Bowyer, J.; Bhushan, C.; Steinnagel, K.; Kaushal, D.; Al-Kinani, G.

1984-03-01

The overall purpose was to forecast the potential United States domestic telecommunications demand for satellite provided customer promises voice, data and video services through the year 2000, so that this information on service demand would be available to aid in NASA program planning. To accomplish this overall purpose the following objectives were achieved: (1) development of a forecast of the total domestic telecommunications demand; (2) identification of that portion of the telecommunications demand suitable for transmission by satellite systems; (3) identification of that portion of the satellite market addressable by consumer promises service (CPS) systems; (4) identification of that portion of the satellite market addressable by Ka-band CPS system; and (5) postulation of a Ka-band CPS network on a nationwide and local level. The approach employed included the use of a variety of forecasting models, a parametric cost model, a market distribution model and a network optimization model. Forecasts were developed for: 1980, 1990, and 2000; voice, data and video services; terrestrial and satellite delivery modes; and C, Ku and Ka-bands.

SOVCAN STAR: An international satellite system

Science.gov (United States)

Skatchkov, Valery A.

SOVCAN STAR is a Russian-Canadian cooperative venture company formed to manufacture, test, launch and operate a Ku-band satellite system. Drawing on the more than twenty years communications satellite experience of the founding companies, the SOVCAN STAR satellites are being designed to be competitive and cost effective. They will be equipped with 24 transponders and four steerable antennas. The design allows the operators to switch individual transponders between the various antenna coverage beams. These satellites will offer a high degree of operational flexibility and performance. The SOVCAN STAR strategy is to develop a network of satellites in parallel with the growth and evolution of the traffic requirements. Such an approach minimizes the technical, schedule and program risks while at the same time significantly reduces the financial exposure. The first SOVCAN STAR satellite will be commissioned in 1996 and operated at 14 deg W. The beams will be aligned to North America and Europe offering International service between Canada, the Eastern U.S.A., Europe, Russia and the Western C.I.S. Republics. The second SOVCAN STAR satellite will be commissioned a year later and operated at 145 deg E. This satellite will cover the Western Pacific Ocean, Eastern Asia and Australasia.

An Unsupervised Anomalous Event Detection and Interactive Analysis Framework for Large-scale Satellite Data

Science.gov (United States)

LIU, Q.; Lv, Q.; Klucik, R.; Chen, C.; Gallaher, D. W.; Grant, G.; Shang, L.

2016-12-01

Due to the high volume and complexity of satellite data, computer-aided tools for fast quality assessments and scientific discovery are indispensable for scientists in the era of Big Data. In this work, we have developed a framework for automated anomalous event detection in massive satellite data. The framework consists of a clustering-based anomaly detection algorithm and a cloud-based tool for interactive analysis of detected anomalies. The algorithm is unsupervised and requires no prior knowledge of the data (e.g., expected normal pattern or known anomalies). As such, it works for diverse data sets, and performs well even in the presence of missing and noisy data. The cloud-based tool provides an intuitive mapping interface that allows users to interactively analyze anomalies using multiple features. As a whole, our framework can (1) identify outliers in a spatio-temporal context, (2) recognize and distinguish meaningful anomalous events from individual outliers, (3) rank those events based on "interestingness" (e.g., rareness or total number of outliers) defined by users, and (4) enable interactively query, exploration, and analysis of those anomalous events. In this presentation, we will demonstrate the effectiveness and efficiency of our framework in the application of detecting data quality issues and unusual natural events using two satellite datasets. The techniques and tools developed in this project are applicable for a diverse set of satellite data and will be made publicly available for scientists in early 2017.

CASTOR: Cathode/Anode Satellite Thruster for Orbital Repositioning

Science.gov (United States)

Mruphy, Gloria A.

2010-01-01

The purpose of CASTOR (Cathode/Anode Satellite Thruster for Orbital Repositioning) satellite is to demonstrate in Low Earth Orbit (LEO) a nanosatellite that uses a Divergent Cusped Field Thruster (DCFT) to perform orbital maneuvers representative of an orbital transfer vehicle. Powered by semi-deployable solar arrays generating 165W of power, CASTOR will achieve nearly 1 km/s of velocity increment over one year. As a technology demonstration mission, success of CASTOR in LEO will pave the way for a low cost, high delta-V orbital transfer capability for small military and civilian payloads in support of Air Force and NASA missions. The educational objective is to engage graduate and undergraduate students in critical roles in the design, development, test, carrier integration and on-orbit operations of CASTOR as a supplement to their curricular activities. This program is laying the foundation for a long-term satellite construction program at MIT. The satellite is being designed as a part of AFRL's University Nanosatellite Program, which provides the funding and a framework in which student satellite teams compete for a launch to orbit. To this end, the satellite must fit within an envelope of 50cmx50cmx60cm, have a mass of less than 50kg, and meet stringent structural and other requirements. In this framework, the CASTOR team successfully completed PDR in August 2009 and CDR in April 2010 and will compete at FCR (Flight Competition Review) in January 2011. The complexity of the project requires implementation of many systems engineering techniques which allow for development of CASTOR from conception through FCR and encompass the full design, fabrication, and testing process.

COSMIC Payload in NCAR-NASPO GPS Satellite System for Severe Weather Prediction

Science.gov (United States)

Lai-Chen, C.

Severe weather, such as cyclones, heavy rainfall, outburst of cold air, etc., results in great disaster all the world. It is the mission for the scientists to design a warning system, to predict the severe weather systems and to reduce the damage of the society. In Taiwan, National Satellite Project Office (NSPO) initiated ROCSAT-3 program at 1997. She scheduled the Phase I conceptual design to determine the mission for observation weather system. Cooperating with National Center of Atmospheric Research (NCAR), NSPO involved an international cooperation research and operation program to build a 32 GPS satellites system. NCAR will offer 24 GPS satellites. The total expanse will be US 100 millions. NSPO also provide US 80 millions for launching and system engineering operation. And NCAR will be responsible for Payload Control Center and Fiducial Network. The cooperative program contract has been signed by Taiwan National Science Council, Taipei Economic Cultural Office of United States and American Institute in Taiwan. One of the payload is COSMIC, Constellation Observation System for Meteorology, Ionosphere and Climate. It is a GPS meteorology instrument system. The system will observe the weather information, e. g. electron density profiles, horizontal and vertical TEC and CFT scintillation and communication outage maps. The mission is to obtain the weather data such as vertical temperature profiles, water vapor distribution and pressure distribution over the world for global weather forecasting, especially during the severe weather period. The COSMIC Conference held on November, 1998. The export license was also issued by Department of Commerce of Unites States at November, 1998. Recently, NSPO begun to train their scientists to investigate the system. Scientists simulate the observation data to combine the existing routine satellite infrared cloud maps, radar echo and synoptic weather analysis for severe weather forecasting. It is hopeful to provide more accurate

Subseabed-disposal program: systems-analysis program plan

International Nuclear Information System (INIS)

Klett, R.D.

1981-03-01

This report contains an overview of the Subseabed Nuclear Waste Disposal Program systems analysis program plan, and includes sensitivity, safety, optimization, and cost/benefit analyses. Details of the primary barrier sensitivity analysis and the data acquisition and modeling cost/benefit studies are given, as well as the schedule through the technical, environmental, and engineering feasibility phases of the program

Nonlinear bias analysis and correction of microwave temperature sounder observations for FY-3C meteorological satellite

Science.gov (United States)

Hu, Taiyang; Lv, Rongchuan; Jin, Xu; Li, Hao; Chen, Wenxin

2018-01-01

The nonlinear bias analysis and correction of receiving channels in Chinese FY-3C meteorological satellite Microwave Temperature Sounder (MWTS) is a key technology of data assimilation for satellite radiance data. The thermal-vacuum chamber calibration data acquired from the MWTS can be analyzed to evaluate the instrument performance, including radiometric temperature sensitivity, channel nonlinearity and calibration accuracy. Especially, the nonlinearity parameters due to imperfect square-law detectors will be calculated from calibration data and further used to correct the nonlinear bias contributions of microwave receiving channels. Based upon the operational principles and thermalvacuum chamber calibration procedures of MWTS, this paper mainly focuses on the nonlinear bias analysis and correction methods for improving the calibration accuracy of the important instrument onboard FY-3C meteorological satellite, from the perspective of theoretical and experimental studies. Furthermore, a series of original results are presented to demonstrate the feasibility and significance of the methods.

V-SIPAL - A VIRTUAL LABORATORY FOR SATELLITE IMAGE PROCESSING AND ANALYSIS

Directory of Open Access Journals (Sweden)

K. M. Buddhiraju

2012-09-01

Full Text Available In this paper a virtual laboratory for the Satellite Image Processing and Analysis (v-SIPAL being developed at the Indian Institute of Technology Bombay is described. v-SIPAL comprises a set of experiments that are normally carried out by students learning digital processing and analysis of satellite images using commercial software. Currently, the experiments that are available on the server include Image Viewer, Image Contrast Enhancement, Image Smoothing, Edge Enhancement, Principal Component Transform, Texture Analysis by Co-occurrence Matrix method, Image Indices, Color Coordinate Transforms, Fourier Analysis, Mathematical Morphology, Unsupervised Image Classification, Supervised Image Classification and Accuracy Assessment. The virtual laboratory includes a theory module for each option of every experiment, a description of the procedure to perform each experiment, the menu to choose and perform the experiment, a module on interpretation of results when performed with a given image and pre-specified options, bibliography, links to useful internet resources and user-feedback. The user can upload his/her own images for performing the experiments and can also reuse outputs of one experiment in another experiment where applicable. Some of the other experiments currently under development include georeferencing of images, data fusion, feature evaluation by divergence andJ-M distance, image compression, wavelet image analysis and change detection. Additions to the theory module include self-assessment quizzes, audio-video clips on selected concepts, and a discussion of elements of visual image interpretation. V-SIPAL is at the satge of internal evaluation within IIT Bombay and will soon be open to selected educational institutions in India for evaluation.

US development and commercialization of a North American mobile satellite service

Science.gov (United States)

Arnold, Ray J.; Gray, Valerie; Freibaum, Jerry

1990-01-01

U.S. policies promoting applications and commercialization of space technology for the 'benefit of mankind,' and emphasis on international competitiveness, formed the basis of NASA's Mobile Satellite (MSAT) R&D and user experiments program to develop a commercial U.S. Mobile Satellite Service. Exemplifying this philosophy, the MSAT program targets the reduction of technical, regulatory, market, and financial risks that inhibit commercialization. The program strategy includes industry and user involvement in developing and demonstrating advanced technologies, regulatory advocacy, and financial incentives to industry. Approximately two decades of NASA's satellite communications development and demonstrations have contributed to the emergence of a new multi-billion dollar industry for land, aeronautical, and maritime mobile communications via satellite. NASA's R&D efforts are now evolving from the development of 'enabling' ground technologies for VHF, UHF, and L-Band mobile terminals, to Ka-Band terminals offering additional mobility and user convenience.

US development and commercialization of a North American mobile satellite service

Science.gov (United States)

Arnold, Ray J.; Gray, Valerie; Freibaum, Jerry

U.S. policies promoting applications and commercialization of space technology for the 'benefit of mankind,' and emphasis on international competitiveness, formed the basis of NASA's Mobile Satellite (MSAT) R&D and user experiments program to develop a commercial U.S. Mobile Satellite Service. Exemplifying this philosophy, the MSAT program targets the reduction of technical, regulatory, market, and financial risks that inhibit commercialization. The program strategy includes industry and user involvement in developing and demonstrating advanced technologies, regulatory advocacy, and financial incentives to industry. Approximately two decades of NASA's satellite communications development and demonstrations have contributed to the emergence of a new multi-billion dollar industry for land, aeronautical, and maritime mobile communications via satellite. NASA's R&D efforts are now evolving from the development of 'enabling' ground technologies for VHF, UHF, and L-Band mobile terminals, to Ka-Band terminals offering additional mobility and user convenience.

NOAA-L satellite arrives at Vandenberg AFB

Science.gov (United States)

2000-01-01

Outside the B16-10 spacecraft processing hangar at Vandenberg Air Force Base, Calif., a crated National Oceanic and Atmospheric Administration (NOAA-L) satellite is lowered to the ground before being moved inside. NOAA-L is part of the Polar-Orbiting Operational Environmental Satellite (POES) program that provides atmospheric measurements of temperature, humidity, ozone and cloud images, tracking weather patterns that affect the global weather and climate. The launch of the NOAA-L satellite is scheduled no earlier than Sept. 12 aboard a Lockheed Martin Titan II rocket. Satellites

International Nuclear Information System (INIS)

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

1986-01-01

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

Satellite Ozone Analysis Center (SOAC)

International Nuclear Information System (INIS)

Lovill, J.E.; Sullivan, T.J.; Knox, J.B.; Korver, J.A.

1976-08-01

Many questions have been raised during the 1970's regarding the possible modification of the ozonosphere by aircraft operating in the stratosphere. Concern also has been expressed over the manner in which the ozonosphere may change in the future as a result of fluorocarbon releases. There are also other ways by which the ozonosphere may be significantly altered, both anthropogenic and natural. Very basic questions have been raised, bearing upon the amount of ozone which would be destroyed by the NO/sub x/ produced in atmospheric nuclear explosions. Studies of the available satellite data have suggested that the worldwide increase of ozone during the past decade, which was observed over land stations, may have been biased by a poor distribution of stations and/or a shift of the planetary wave. Additional satellite data will be required to resolve this issue. Proposals are presented for monitoring of the Earth's ozone variability from the present time into the 1980's to establish a baseline upon which regional, as well as global, ozone trends can be measured

Enhancing STEM Education through Cubesats: Using Satellite Integration as a Teaching Tool at a Non-Tech School

Science.gov (United States)

Bernardes, S.; Cotten, D. L.

2016-12-01

University-based satellite programs have been successfully used as a platform for teaching STEM related fields, bringing tremendous benefits to graduate and undergraduate education. Considering their infrastructure and curricula, tech schools have traditionally been considered logical candidates for hosting such programs. More recently, with the dissemination of small satellites initiatives, non-tech schools have been presented the opportunity of developing satellite design and implementation programs. This work reports on the experiences and challenges associated with implementing a satellite program at the University of Georgia (UGA), a non-tech university. With funding from the Air Force Research Laboratory's (AFRL) University Nanosat Program (UNP) and NASA's Undergraduate Student Instrument Project (USIP) a team of undergraduates at UGA has recently been tasked with building two small satellites and helping to create a Small Satellite Research Laboratory (SSRL) at the university. Unique features of the satellite program at UGA include its team of students from a broad range of backgrounds and departments (Engineering, Computer Science, Art, Business, and Geography) and the previous exposure of many of these students to synergistic technologies, including arduino and unmanned aerial systems. We show how informal exposure to those technologies and willingness of students to focus on areas outside of their field of study can benefit from the implementation of satellite programs. In this regard, we report on methods and techniques used to find and recruit driven and knowledgeable students to work in a high paced field such as satellite system integration. We show how students and faculty from multiple departments have collaborated to reach a common, far reaching goal and describe our proposed methods to evaluate and measure educational goals based around SSRL and its projects. We also present the challenges associated with the lack of a developed engineering

Analysis of rain fade duration models for Earth-to-satellite path based on data measured in Malaysia

International Nuclear Information System (INIS)

Dao, Hassan; Rafiqul, Islam Md; Al-Khateeb, Khalid A S

2013-01-01

Statistical analysis of rain fade duration is crucial information for system engineer to design and plan a fade mitigation technique (FMT) for the satellite communication system. An investigation is carried out based on data measured of one year period in Kuala Lumpur, Malaysia from satellite path of MEASAT3. This paper presents statistical analysis of measured fade duration on high elevation angle (77.4°) in Ku-band compared to three prediction models of fade duration. It is found that none of the models could predict measured fade duration distribution accurately

Development and Analysis of Image Registration Program for the Communication, Ocean, Meteorological Satellite (COMS

Directory of Open Access Journals (Sweden)

Un-Seob Lee

2007-09-01

Full Text Available We developed a software for simulations and analyses of the Image Navigation and Registration (INR system, and compares the characteristics of Image Motion Compensation (IMC algorithms for the INR system. According to the orbit errors and attitude errors, the capabilities of the image distortions are analyzed. The distortions of images can be compensated by GOES IMC algorithm and Modified IMC (MIMC algorithm. The capabilities of each IMC algorithm are confirmed based on compensated images. The MIMC yields better results than GOES IMC although both the algorithms well compensate distorted images. The results of this research can be used as valuable asset to design of INR system for the Communication, Ocean, Meteorological Satellite (COMS.

Comparative Analysis of Satellite DNA in the Drosophila melanogaster Species Complex

Directory of Open Access Journals (Sweden)

Madhav Jagannathan

2017-02-01

Full Text Available Satellite DNAs are highly repetitive sequences that account for the majority of constitutive heterochromatin in many eukaryotic genomes. It is widely recognized that sequences and locations of satellite DNAs are highly divergent even in closely related species, contributing to the hypothesis that satellite DNA differences may underlie speciation. However, due to its repetitive nature, the mapping of satellite DNAs has been mostly left out of recent genomics analyses, hampering the use of molecular genetics techniques to better understand their role in speciation and evolution. Satellite DNAs are most extensively and comprehensively mapped in Drosophila melanogaster, a species that is also an excellent model system with which to study speciation. Yet the lack of comprehensive knowledge regarding satellite DNA identity and location in its sibling species (D. simulans, D. mauritiana, and D. sechellia has prevented the full utilization of D. melanogaster in studying speciation. To overcome this problem, we initiated the mapping of satellite DNAs on the genomes of the D. melanogaster species complex (D. melanogaster, D. simulans, D. mauritiana, and D. sechellia using multi-color fluorescent in situ hybridization (FISH probes. Our study confirms a striking divergence of satellite DNAs in the D. melanogaster species complex, even among the closely related species of the D. simulans clade (D. simulans, D. mauritiana, and D. sechellia, and suggests the presence of unidentified satellite sequences in these species.

Status of Satellite Television Broadcast Programs Implementation in ...

African Journals Online (AJOL)

As the ICT domination in our day to day life is increasing, the Ethiopian Government convinced to utilize its opportunity for improving quality of education by introducing plasma television learning media in high schools of the country. The objective of this study was to determine implementation status of satellite plasma ...

Laurel Clark Earth Camp: A Program for Teachers and Students to Explore Their World and Study Global Change Through Field-Experience and Satellite Images

Science.gov (United States)

Buxner, S.; Orchard, A.; Colodner, D.; Schwartz, K.; Crown, D. A.; King, B.; Baldridge, A.

2012-03-01

The Laurel Clark Earth Camp program provides middle and high school students and teachers opportunities to explore local environmental issues and global change through field-experiences, inquiry exercises, and exploring satellite images.

Geostationary satellites collocation

CERN Document Server

Li, Hengnian

2014-01-01

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.

Configurable software for satellite graphics

Energy Technology Data Exchange (ETDEWEB)

Hartzman, P D

1977-12-01

An important goal in interactive computer graphics is to provide users with both quick system responses for basic graphics functions and enough computing power for complex calculations. One solution is to have a distributed graphics system in which a minicomputer and a powerful large computer share the work. The most versatile type of distributed system is an intelligent satellite system in which the minicomputer is programmable by the application user and can do most of the work while the large remote machine is used for difficult computations. At New York University, the hardware was configured from available equipment. The level of system intelligence resulted almost completely from software development. Unlike previous work with intelligent satellites, the resulting system had system control centered in the satellite. It also had the ability to reconfigure software during realtime operation. The design of the system was done at a very high level using set theoretic language. The specification clearly illustrated processor boundaries and interfaces. The high-level specification also produced a compact, machine-independent virtual graphics data structure for picture representation. The software was written in a systems implementation language; thus, only one set of programs was needed for both machines. A user can program both machines in a single language. Tests of the system with an application program indicate that is has very high potential. A major result of this work is the demonstration that a gigantic investment in new hardware is not necessary for computing facilities interested in graphics.

VLBI Observations of Geostationary Satellites

Science.gov (United States)

Artz, T.; Nothnagel, A.; La Porta, L.

2013-08-01

For a consistent realization of a Global Geodetic Observing System (GGOS), a proper tie between the individual global reference systems used in the analysis of space-geodetic observations is a prerequisite. For instance, the link between the terrestrial, the celestial and the dynamic reference system of artificial Earth orbiters may be realized by Very Long O Baseline Interferometry (VLBI) observations of one or several satellites. In the preparation phase for a dedicated satellite mission, one option to realize this is using a geostationary (GEO) satellite emitting a radio signal in X-Band and/or S-Band and, thus, imitating a quasar. In this way, the GEO satellite can be observed by VLBI together with nearby quasars and the GEO orbit can, thus, be determined in a celestial reference frame. If the GEO satellite is, e.g., also equipped with a GNSS-type transmitter, a further tie between GNSS and VLBI may be realized. In this paper, a concept for the generation of a radio signal is shown. Furthermore, simulation studies for estimating the GEO position are presented with a GEO satellite included in the VLBI schedule. VLBI group delay observations are then simulated for the quasars as well as for the GEO satellite. The analysis of the simulated observations shows that constant orbit changes are adequately absorbed by estimated orbit parameters. Furthermore, the post-fit residuals are comparable to those from real VLBI sessions.

CBERS-2B Brazilian remote sensing satellite to help to monitor the Bolivia-Brazil gas pipeline

Energy Technology Data Exchange (ETDEWEB)

Hernandes, Gilberto Luis Sanches [TBG Transportadora Brasileira Gasoduto Bolivia-Brasil, Rio de Janeiro, RJ (Brazil)

2009-07-01

This paper presents the results of CBERS-2B' Brazilian Remote Sensing Satellite to help to monitor the Bolivia-Brazil Gas Pipeline. The CBERS-2B is the third satellite launched in 2007 by the CBERS Program (China-Brazil Earth Resources Satellite) and the innovation was the HRC camera that produces high resolution images. It will be possible to obtain one complete coverage of the country every 130 days. In this study, 2 images from different parts of the Bolivia- Brazil Gas Pipeline were selected. Image processing involved the geometric registration of CBERS-2B satellite images with airborne images, contrast stretch transform and pseudo color. The analysis of satellite and airborne images in a GIS software to detect third party encroachment was effective to detect native vegetation removal, street construction, growth of urban areas, farming and residential/industrial land development. Very young, the CBERS-2B is a good promise to help to inspect the areas along the pipelines. (author)

LULU analysis program

International Nuclear Information System (INIS)

Crawford, H.J.; Lindstrom, P.J.

1983-06-01

Our analysis program LULU has proven very useful in all stages of experiment analysis, from prerun detector debugging through final data reduction. It has solved our problem of having arbitrary word length events and is easy enough to use that many separate experimenters are now analyzing with LULU. The ability to use the same software for all stages of experiment analysis greatly eases the programming burden. We may even get around to making the graphics elegant someday

A Platform for Scalable Satellite and Geospatial Data Analysis

Science.gov (United States)

Beneke, C. M.; Skillman, S.; Warren, M. S.; Kelton, T.; Brumby, S. P.; Chartrand, R.; Mathis, M.

2017-12-01

At Descartes Labs, we use the commercial cloud to run global-scale machine learning applications over satellite imagery. We have processed over 5 Petabytes of public and commercial satellite imagery, including the full Landsat and Sentinel archives. By combining open-source tools with a FUSE-based filesystem for cloud storage, we have enabled a scalable compute platform that has demonstrated reading over 200 GB/s of satellite imagery into cloud compute nodes. In one application, we generated global 15m Landsat-8, 20m Sentinel-1, and 10m Sentinel-2 composites from 15 trillion pixels, using over 10,000 CPUs. We recently created a public open-source Python client library that can be used to query and access preprocessed public satellite imagery from within our platform, and made this platform available to researchers for non-commercial projects. In this session, we will describe how you can use the Descartes Labs Platform for rapid prototyping and scaling of geospatial analyses and demonstrate examples in land cover classification.

Structural assurance testing for post-shipping satellite inspection

Science.gov (United States)

Reynolds, Whitney D.; Doyle, Derek; Arritt, Brandon

2012-04-01

Current satellite transportation sensors can provide a binary indication of the acceleration or shock that a satellite has experienced during the shipping process but do little to identify if significant structural change has occurred in the satellite and where it may be located. When a sensor indicates that the satellite has experienced shock during transit, an extensive testing process begins to evaluate the satellite functionality. If errors occur during the functional checkout, extensive physical inspection of the structure follows. In this work an alternate method for inspecting satellites for structural defects after shipping is presented. Electro- Mechanical Impedance measurements are used as an indication of the structural state. In partnership with the Air Force Research Laboratory University Nanosatellite Program, Cornell's CUSat mass model was instrumented with piezoelectric transducers and tested under several structural damage scenarios. A method for detecting and locating changes in the structure using EMI data is presented.

Satellite DNA: An Evolving Topic.

Science.gov (United States)

Garrido-Ramos, Manuel A

2017-09-18

Satellite DNA represents one of the most fascinating parts of the repetitive fraction of the eukaryotic genome. Since the discovery of highly repetitive tandem DNA in the 1960s, a lot of literature has extensively covered various topics related to the structure, organization, function, and evolution of such sequences. Today, with the advent of genomic tools, the study of satellite DNA has regained a great interest. Thus, Next-Generation Sequencing (NGS), together with high-throughput in silico analysis of the information contained in NGS reads, has revolutionized the analysis of the repetitive fraction of the eukaryotic genomes. The whole of the historical and current approaches to the topic gives us a broad view of the function and evolution of satellite DNA and its role in chromosomal evolution. Currently, we have extensive information on the molecular, chromosomal, biological, and population factors that affect the evolutionary fate of satellite DNA, knowledge that gives rise to a series of hypotheses that get on well with each other about the origin, spreading, and evolution of satellite DNA. In this paper, I review these hypotheses from a methodological, conceptual, and historical perspective and frame them in the context of chromosomal organization and evolution.

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

Science.gov (United States)

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

1974-01-01

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

Multi precursors analysis associated with the powerful Ecuador (MW = 7.8) earthquake of 16 April 2016 using Swarm satellites data in conjunction with other multi-platform satellite and ground data

Science.gov (United States)

Akhoondzadeh, Mehdi; De Santis, Angelo; Marchetti, Dedalo; Piscini, Alessandro; Cianchini, Gianfranco

2018-01-01

After DEMETER satellite mission (2004-2010), the launch of the Swarm satellites (Alpha (A), Bravo (B) and Charlie (C)) has created a new opportunity in the study of earthquake ionospheric precursors. Nowadays, there is no doubt that multi precursors analysis is a necessary phase to better understand the LAIC (Lithosphere Atmosphere Ionosphere Coupling) mechanism before large earthquakes. In this study, using absolute scalar magnetometer, vector field magnetometer and electric field instrument on board Swarm satellites, GPS (Global Positioning System) measurements, MODIS-Aqua satellite and ECMWF (European Centre for Medium-Range Weather Forecasts) data, the variations of the electron density and temperature, magnetic field, TEC (Total Electron Content), LST (Land Surface Temperature), AOD (Aerosol Optical Depth) and SKT (SKin Temperature) have been surveyed to find the potential seismic anomalies around the strong Ecuador (Mw = 7.8) earthquake of 16 April 2016. The four solar and geomagnetic indices: F10.7, Dst, Kp and ap were investigated to distinguish whether the preliminary detected anomalies might be associated with the solar-geomagnetic activities instead of the seismo-ionospheric anomalies. The Swarm satellites (A, B and C) data analysis indicate the anomalies in time series of electron density variations on 7, 11 and 12 days before the event; the unusual variations in time series of electron temperature on 8 days preceding the earthquake; the analysis of the magnetic field scalar and vectors data show the considerable anomalies 52, 48, 23, 16, 11, 9 and 7 days before the main shock. A striking anomaly is detected in TEC variations on 1 day before earthquake at 9:00 UTC. The analysis of MODIS-Aqua night-time images shows that LST increase unusually on 11 days prior to main shock. In addition, the AOD variations obtained from MODIS measurements reach the maximum value on 10 days before the earthquake. The SKT around epicentral region presents anomalous higher

Umatilla Satellite and Release Sites Project : Final Siting Report.

Energy Technology Data Exchange (ETDEWEB)

Montgomery, James M.

1992-04-01

This report presents the results of site analysis for the Umatilla Satellite and Release Sites Project. The purpose of this project is to provide engineering services for the siting and conceptual design of satellite and release facilities for the Umatilla Basin hatchery program. The Umatilla Basin hatchery program consists of artificial production facilities for salmon and steelhead to enhance production in the Umatilla River as defined in the Umatilla master plan approved in 1989 by the Northwest Power Planning Council. Facilities identified in the master plan include adult salmon broodstock holding and spawning facilities, facilities for recovery, acclimation, and/or extended rearing of salmon juveniles, and development of river sites for release of hatchery salmon and steelhead. The historic and current distribution of fall chinook, summer chinook, and coho salmon and steelhead trout was summarized for the Umatilla River basin. Current and future production and release objectives were reviewed. Twenty seven sites were evaluated for the potential and development of facilities. Engineering and environmental attributes of the sites were evaluated and compared to facility requirements for water and space. Site screening was conducted to identify the sites with the most potential for facility development. Alternative sites were selected for conceptual design of each facility type. A proposed program for adult holding facilities, final rearing/acclimation, and direct release facilities was developed.

Handbook of satellite applications

CERN Document Server

Madry, Scott; Camacho-Lara, Sergio

2013-01-01

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...

Cultures in orbit: Satellite technologies, global media and local practice

Science.gov (United States)

Parks, Lisa Ann

Since the launch of Sputnik in 1957, satellite technologies have had a profound impact upon cultures around the world. "Cultures in Orbit" examines these seemingly disembodied, distant relay machines in relation to situated social and cultural processes on earth. Drawing upon a range of materials including NASA and UNESCO documents, international satellite television broadcasts, satellite 'development' projects, documentary and science fiction films, remote sensing images, broadcast news footage, World Wide Web sites, and popular press articles I delineate and analyze a series of satellite mediascapes. "Cultures in Orbit" analyzes uses of satellites for live television relay, surveillance, archaeology and astronomy. The project examines such satellite media as the first live global satellite television program Our World, Elvis' Aloha from Hawaii concert, Aboriginal Australian satellite programs, and Star TV's Asian music videos. In addition, the project explores reconnaissance images of mass graves in Bosnia, archaeological satellite maps of Cleopatra's underwater palace in Egypt, and Hubble Space Telescope images. These case studies are linked by a theoretical discussion of the satellite's involvement in shifting definitions of time, space, vision, knowledge and history. The satellite fosters an aesthetic of global realism predicated on instantaneous transnational connections. It reorders linear chronologies by revealing traces of the ancient past on the earth's surface and by searching in deep space for the "edge of time." On earth, the satellite is used to modernize and develop "primitive" societies. Satellites have produced new electronic spaces of international exchange, but they also generate strategic maps that advance Western political and cultural hegemony. By technologizing human vision, the satellite also extends the epistemologies of the visible, the historical and the real. It allows us to see artifacts and activities on earth from new vantage points

Tropical Rainfall Analysis Using TRMM in Combination With Other Satellite Gauge Data: Comparison with Global Precipitation Climatology Project (GPCP) Results

Science.gov (United States)

Adler, Robert F.; Huffman, George J.; Bolvin, David; Nelkin, Eric; Curtis, Scott

1999-01-01

This paper describes recent results of using Tropical Rainfall Measuring Mission (TRMM) information as the key calibration tool in a merged analysis on a 1 deg x 1 deg latitude/longitude monthly scale based on multiple satellite sources and raingauge analysis. The procedure used to produce the GPCP data set is a stepwise approach which first combines the satellite low-orbit microwave and geosynchronous IR observations into a "multi-satellite" product and than merges that result with the raingauge analysis. Preliminary results produced with the still-stabilizing TRMM algorithms indicate that TRMM shows tighter spatial gradients in tropical rain maxima with higher peaks in the center of the maxima. The TRMM analyses will be used to evaluate the evolution of the 1998 ENSO variations, again in comparison with the GPCP analyses.

A Program Transformation for Backwards Analysis of Logic Programs

DEFF Research Database (Denmark)

Gallagher, John Patrick

2003-01-01

The input to backwards analysis is a program together with properties that are required to hold at given program points. The purpose of the analysis is to derive initial goals or pre-conditions that guarantee that, when the program is executed, the given properties hold. The solution for logic...... programs presented here is based on a transformation of the input program, which makes explicit the dependencies of the given program points on the initial goals. The transformation is derived from the resultants semantics of logic programs. The transformed program is then analysed using a standard...

Estimating Effects Of Rain On Ground/Satellite Communication

Science.gov (United States)

Manning, R. M.

1992-01-01

LeRC-SLAM provides static and dynamic statistical assessment of impact of attenuation by rain on communication link established between Earth terminal and geosynchronous satellite. Program designed for use in specification, design, and assessment of satellite link for any terminal location in continental United States. IBM PC version written in Microsoft QuickBASIC, and Macintosh version written in Microsoft Basic.

Aerosols, Chemistry, and Radiative Forcing: A 3-D Model Analysis of Satellite and ACE-Asia data (ACMAP)

Science.gov (United States)

Chin, Mian; Ginoux, Paul; Torres, Omar; Zhao, Xue-Peng

2005-01-01

We propose a research project to incorporate a global 3-D model and satellite data into the multi-national Aerosol Characterization Experiment-Asia (ACE-Asia) mission. Our objectives are (1) to understand the physical, chemical, and optical properties of aerosols and the processes that control those properties over the Asian-Pacific region, (2) to investigate the interaction between aerosols and tropospheric chemistry, and (3) to determine the aerosol radiative forcing over the Asia-Pacific region. We will use the Georgia TecWGoddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model to link satellite observations and the ACE-Asia measurements. First, we will use the GOCART model to simulate aerosols and related species, and evaluate the model with satellite and in-situ observations. Second, the model generated aerosol vertical profiles and compositions will be used to validate the satellite products; and the satellite data will be used for during- and post- mission analysis. Third, we will use the model to analyze and interpret both satellite and ACE- Asia field campaign data and investigate the aerosol-chemistry interactions. Finally, we will calculate aerosol radiative forcing over the Asian-Pacific region, and assess the influence of Asian pollution in the global atmosphere. We propose a research project to incorporate a global 3-D model and satellite data into

Satellite Power Systems (SPS) concept definition study. Volume 2, part 2: System engineering. [cost and programmatics

Science.gov (United States)

Hanley, G. M.

1980-01-01

The latest technical and programmatic developments are considered as well as expansions of the Rockwell SPS cost model covering each phase of the program through the year 2030. Comparative cost/economic analyses cover elements of the satellite, construction system, space transportation vehicles and operations, and the ground receiving station. System plans to define time phased costs and planning requirements that support major milestones through the year 2000. A special analysis is included on natural resources required to build the SPS reference configuration. An appendix contains the SPS Work Breakdown Structure and dictionary along with detail cost data sheet on each system and main element of the program. Over 200 line items address DDT&E, theoretical first unit, investment cost per satellite, and operations charges for replacement capital and normal operations and maintenance costs.

Analysis on coverage ability of BeiDou navigation satellite system for manned spacecraft

Science.gov (United States)

Zhao, Sihao; Yao, Zheng; Zhuang, Xuebin; Lu, Mingquan

2014-12-01

To investigate the service ability of the BeiDou Navigation Satellite System (BDS) for manned spacecraft, both the current regional and the future-planned global constellations of BDS are introduced and simulated. The orbital parameters of the International Space Station and China's Tiangong-1 spacelab are used to create the simulation scenario and evaluate the performance of the BDS constellations. The number of visible satellites and the position dilution (PDOP) of precision at the spacecraft-based receiver are evaluated. Simulation and analysis show quantitative results on the coverage ability and time percentages of both the current BDS regional and future global constellations for manned-space orbits which can be a guideline to the applications and mission design of BDS receivers on manned spacecraft.

Proceedings of the 2015 National Toxicology Program Satellite Symposium.

Science.gov (United States)

Elmore, Susan A; Farman, Cindy A; Hailey, James R; Kovi, Ramesh C; Malarkey, David E; Morrison, James P; Neel, Jennifer; Pesavento, Patricia A; Porter, Brian F; Szabo, Kathleen A; Teixeira, Leandro B C; Quist, Erin M

2016-06-01

The 2015 Annual National Toxicology Program Satellite Symposium, entitled "Pathology Potpourri" was held in Minneapolis, Minnesota, at the American College of Veterinary Pathologists/American Society for Veterinary Clinical Pathology/Society of Toxicologic Pathology combined meeting. The goal of this symposium is to present and discuss diagnostic pathology challenges or nomenclature issues. Because of the combined meeting, both laboratory and domestic animal cases were presented. This article presents summaries of the speakers' talks, including challenging diagnostic cases or nomenclature issues that were presented, along with select images that were used for audience voting and discussion. Some lesions and topics covered during the symposium included hepatocellular lesions, a proposed harmonized diagnostic approach to rat cardiomyopathy, crop milk in a bird, avian feeding accoutrement, heat exchanger in a tuna, metastasis of a tobacco carcinogen-induced pulmonary carcinoma, neurocytoma in a rat, pituicytoma in a rat, rodent mammary gland whole mounts, dog and rat alveolar macrophage ultrastructure, dog and rat pulmonary phospholipidosis, alveolar macrophage aggregation in a dog, degenerating yeast in a cat liver aspirate, myeloid leukemia in lymph node aspirates from a dog, Trypanosoma cruzi in a dog, solanum toxicity in a cow, bovine astrovirus, malignant microglial tumor, and nomenclature challenges from the Special Senses International Harmonization of Nomenclature and Diagnostic Criteria Organ Working Group. © The Author(s) 2016.

Analysis of Visual Interpretation of Satellite Data

Science.gov (United States)

Svatonova, H.

2016-06-01

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.

ANALYSIS OF VISUAL INTERPRETATION OF SATELLITE DATA

Directory of Open Access Journals (Sweden)

H. Svatonova

2016-06-01

Full Text Available 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.

Power Processing Unit For Micro Satellite Electric Propulsion System

Directory of Open Access Journals (Sweden)

Savvas Spiridon

2017-01-01

Full Text Available The Micro Satellite Electric Propulsion System (MEPS program has been originated by the increasing need to provide a low-cost and low-power Electric Propulsion System (EPS for small satellites ( 92%, small size and weight and high reliability. Its functional modules and preliminary results obtained at breadboard level are also presented.

Validation of satellite data through the remote sensing techniques and the inclusion of them into agricultural education pilot programs

Science.gov (United States)

Papadavid, Georgios; Kountios, Georgios; Bournaris, T.; Michailidis, Anastasios; Hadjimitsis, Diofantos G.

2016-08-01

Nowadays, the remote sensing techniques have a significant role in all the fields of agricultural extensions as well as agricultural economics and education but they are used more specifically in hydrology. The aim of this paper is to demonstrate the use of field spectroscopy for validation of the satellite data and how combination of remote sensing techniques and field spectroscopy can have more accurate results for irrigation purposes. For this reason vegetation indices are used which are mostly empirical equations describing vegetation parameters during the lifecycle of the crops. These numbers are generated by some combination of remote sensing bands and may have some relationship to the amount of vegetation in a given image pixel. Due to the fact that most of the commonly used vegetation indices are only concerned with red-near-infrared spectrum and can be divided to perpendicular and ratio based indices the specific goal of the research is to illustrate the effect of the atmosphere to those indices, in both categories. In this frame field spectroscopy is employed in order to derive the spectral signatures of different crops in red and infrared spectrum after a campaign of ground measurements. The main indices have been calculated using satellite images taken at interval dates during the whole lifecycle of the crops by using a GER 1500 spectro-radiomete. These indices was compared to those extracted from satellite images after applying an atmospheric correction algorithm -darkest pixel- to the satellite images at a pre-processing level so as the indices would be in comparable form to those of the ground measurements. Furthermore, there has been a research made concerning the perspectives of the inclusion of the above mentioned remote satellite techniques to agricultural education pilot programs.

A standard library for modeling satellite orbits on a microcomputer

Science.gov (United States)

Beutel, Kenneth L.

1988-03-01

Introductory students of astrodynamics and the space environment are required to have a fundamental understanding of the kinematic behavior of satellite orbits. This thesis develops a standard library that contains the basic formulas for modeling earth orbiting satellites. This library is used as a basis for implementing a satellite motion simulator that can be used to demonstrate orbital phenomena in the classroom. Surveyed are the equations of orbital elements, coordinate systems and analytic formulas, which are made into a standard method for modeling earth orbiting satellites. The standard library is written in the C programming language and is designed to be highly portable between a variety of computer environments. The simulation draws heavily on the standards established by the library to produce a graphics-based orbit simulation program written for the Apple Macintosh computer. The simulation demonstrates the utility of the standard library functions but, because of its extensive use of the Macintosh user interface, is not portable to other operating systems.

Liquid Effluents Program mission analysis

International Nuclear Information System (INIS)

Lowe, S.S.

1994-01-01

Systems engineering is being used to identify work to cleanup the Hanford Site. The systems engineering process transforms an identified mission need into a set of performance parameters and a preferred system configuration. Mission analysis is the first step in the process. Mission analysis supports early decision-making by clearly defining the program objectives, and evaluating the feasibility and risks associated with achieving those objectives. The results of the mission analysis provide a consistent basis for subsequent systems engineering work. A mission analysis was performed earlier for the overall Hanford Site. This work was continued by a ''capstone'' team which developed a top-level functional analysis. Continuing in a top-down manner, systems engineering is now being applied at the program and project levels. A mission analysis was conducted for the Liquid Effluents Program. The results are described herein. This report identifies the initial conditions and acceptable final conditions, defines the programmatic and physical interfaces and sources of constraints, estimates the resources to carry out the mission, and establishes measures of success. The mission analysis reflects current program planning for the Liquid Effluents Program as described in Liquid Effluents FY 1995 Multi-Year Program Plan

Joint Polar Satellite System: the United States New Generation Civilian Polar Orbiting Environmental Satellite System

Science.gov (United States)

Mandt, G.

2017-12-01

The Joint Polar Satellite System (JPSS) is the Nation's advanced series of polar-orbiting environmental satellites. JPSS represents significant technological and scientific advancements in observations used for severe weather prediction and environmental monitoring. The Suomi National Polar-orbiting Partnership (S-NPP) is providing state-of-the art atmospheric, oceanographic, and environmental data, as the first of the JPSS satellites while the second in the series, J-1, is scheduled to launch in October 2017. The JPSS baseline consists of a suite of four instruments: an advanced microwave and infrared sounders which are critical for weather forecasting; a leading-edge visible and infrared imager critical to data sparse areas such as Alaska and needed for environmental assessments such as snow/ice cover, droughts, volcanic ash, forest fires and surface temperature; and an ozone sensor primarily used for global monitoring of ozone and input to weather and climate models. The same suite of instruments that are on JPSS-1 will be on JPSS-2, 3 and 4. The JPSS-2 instruments are well into their assembly and test phases and are scheduled to be completed in 2018. The JPSS-2 spacecraft critical design review (CDR) is scheduled for 2Q 2018 with the launch in 2021. The sensors for the JPSS-3 and 4 spacecraft have been approved to enter into their acquisition phases. JPSS partnership with the US National Aeronautics and Space Agency (NASA) continues to provide a strong foundation for the program's success. JPSS also continues to maintain its important international relationships with European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and the Japan Aerospace Exploration Agency (JAXA). JPSS works closely with its user community through the Proving Ground and Risk Reduction (PGRR) Program to identify opportunities to maximize the operational application of current JPSS capabilities. The PGRR Program also helps identify and evaluate the use of JPSS

Enhanced ionosphere-magnetosphere data from the DMSP satellites

International Nuclear Information System (INIS)

Rich, F.J.; Hardy, D.A.; Gussenhoven, M.S.

1985-01-01

The satellites of the Defense Meteorological Satellite Program (DMSP) represent a series of low-altitude (835 km) polar-orbiting satellites. Their primary objective is related to the observation of the tropospheric weather with a high-resolution white light and infrared imaging system. It is also possible to make images of auroras. On a daily basis, information about auroras is used to assist various communication systems which are affected by the ionospheric disturbances associated with auroras. In the past few years, there have been several improvements in the ionospheric monitoring instrumentation. Since the high-latitude ionosphere is connected to the magnetosphere, the DMSP data are used to monitor magnetospheric processes. The instrumentation of the DMSP satellites is discussed, taking into account the data provided by them. 7 references

Specificity of Atmosphere Correction of Satellite Ocean Color Data in Far-Eastern Region

Science.gov (United States)

Trusenkova, O.; Kachur, V.; Aleksanin, A. I.

2016-02-01

It was carried out an error analysis of satellite reflectance coefficients (Rrs) of MODIS/AQUA colour data for two atmospheric correction algorithms (NIR, MUMM) in the Far-Eastern region. Some sets of unique data of in situ and satellite measurements have been analysed. A set has some measurements with ASD spectroradiometer for each satellite pass. The measurement allocations were selected so the Chlorophyll-a concentration has high variability. Analysis of arbitrary set demonstrated that the main error component is systematic error, and it has simple relations on Rrs values. The reasons of such error behavior are considered. The most probable explanation of the large errors of oceanic color parameters in the Far-Eastern region is the ability of high concentrations of continental aerosol. A comparison of satellite and in situ measurements at AERONET stations of USA and South Korea regions has been made. It was shown that for NIR-correction of the atmosphere influence the error values in these two regions have differences up to 10 times for almost the same water turbidity and relatively good accuracy of computation of aerosol optical thickness. The study was supported by grant Russian Scientific Foundation No. 14-50-00034, by grant of Russian Foundation of Basic Research No.15-35-21032-mol-a-ved, and by Program of Basic Research "Far East" of Far Eastern Branch of Russian Academy of Sciences.

Advances in analysis of pre-earthquake thermal anomalies by analyzing IR satellite data

Science.gov (United States)

Ouzounov, D.; Bryant, N.; Filizzola, C.; Pergola, N.; Taylor, P.; Tramutoli, V.

Presented work addresses the possible relationship between tectonic stress, electro-chemical and thermodynamic processes in the atmosphere and increasing infrared (IR) flux as part of a larger family of electromagnetic (EM) phenomena related to earthquake activity. Thermal infra-red (TIR) surveys performed by polar orbiting (NOAA/AVHRR, MODIS) and geosynchronous weather satellites (GOES, METEOSAT) seems to indicate the appearance (from days to weeks before the event) of "anomalous" space-time TIR transients associated with the place (epicentral area, linear structures and fault systems) and the time of occurrence of a number of major earthquakes with M>5 and focal depths no deeper than 50km. As Earth emitted in 8-14 microns range the TIR signal measured from satellite strongly vary depending on meteorological conditions and other factors (space-time changes in atmospheric transmittance, time/season, solar and satellite zenithal angles and etc) independent from seismic activity, a preliminary definition of "anomalous TIR signal" should be given. To provide reliable discrimination of thermal anomalous area from the natural events (seasonal changes, local morphology) new robust approach (RAT) has been recently proposed (and successfully applied in the field of the monitoring of the major environmental risks) that permits to give a statistically based definition of thermal info-red (TIR) anomaly and reduce of false events detection. New techniques also were specifically developed to assure the precise co-registration of all satellite scenes and permit accurate time-series analysis of satellite observations. As final results we present examples of most recent 2000/2004 worldwide strong earthquakes and the techniques used to capture the tracks of thermal emission mid-IR anomalies and methodology for practical future use of such phenomena in the early warning systems.

Satellite communications principles and applications

CERN Document Server

Calcutt, David

1994-01-01

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

Tree Canopy Light Interception Estimates in Almond and a Walnut Orchards Using Ground, Low Flying Aircraft, and Satellite Based Methods to Improve Irrigation Scheduling Programs

Science.gov (United States)

Rosecrance, Richard C.; Johnson, Lee; Soderstrom, Dominic

2016-01-01

Canopy light interception is a main driver of water use and crop yield in almond and walnut production. Fractional green canopy cover (Fc) is a good indicator of light interception and can be estimated remotely from satellite using the normalized difference vegetation index (NDVI) data. Satellite-based Fc estimates could be used to inform crop evapotranspiration models, and hence support improvements in irrigation evaluation and management capabilities. Satellite estimates of Fc in almond and walnut orchards, however, need to be verified before incorporating them into irrigation scheduling or other crop water management programs. In this study, Landsat-based NDVI and Fc from NASA's Satellite Irrigation Management Support (SIMS) were compared with four estimates of canopy cover: 1. light bar measurement, 2. in-situ and image-based dimensional tree-crown analyses, 3. high-resolution NDVI data from low flying aircraft, and 4. orchard photos obtained via Google Earth and processed by an Image J thresholding routine. Correlations between the various estimates are discussed.

About Nano-JASMINE Satellite System and Project Status

Science.gov (United States)

Sako, Nobutada

Intelligent Space Systems Laboratory, The University of Tokyo (ISSL) and National Astronomical Observatory of Japan (NAO) have been developing a small infrared astrometry satellite named “Nano-JASMINE”. The satellite size is about 50cm cubic and 20kg, which plays a pre-cursor role of JASMINE Project which is programmed by NAO and JAXA. In addition, since there has been only one astrometry satellite HIPPARCOS by ESA in the past, Nano-JASMINE is also expected to achieve certain scientific results in the field of astrometry. In this project, ISSL aims to develop new advanced small satellite bus system whose performance is comparable to that of 100-500kg sized satellites, including attitude stability of 1 arc-second and thermal stability of the mission subsystem of 1 mK. This paper overviews the Nano-JASMINE bus system with emphasis on attitude and thermal control systems.

A Fortran Program for Deep Space Sensor Analysis.

Science.gov (United States)

1984-12-14

used to help p maintain currency to the deep space satellite catelog? Research Question Can a Fortran program be designed to evaluate the effectiveness ...Range ( AFETR ) Range p Measurements Laboratory (RML) is located in Malibar, .- Florida. Like GEODSS, Malibar uses a 48 inch telescope with a...phased out. This mode will evaluate the effect of the loss of the 3 Baker-Nunn sites to mode 3 Mode 5 through Mode 8 Modes 5 through 8 are identical to

IAEA Safeguards: Cost/benefit analysis of commercial satellite imagery

International Nuclear Information System (INIS)

Andersson, Christer

1999-03-01

A major milestone in the efforts to strengthen the Safeguards System was reached in May 1997 when the Board of Governors approved a 'Model Protocol Additional to Safeguards Agreements'. The Protocol provides the legal basis necessary to enhance the Agency's ability to detect undeclared nuclear material and activities by using information available from open sources to complement the declarations made by Member States. Commercially available high-resolution satellite data has emerged as one potential complementary open information source to support the traditional and extended Safeguard activities of IAEA. This document constitutes a first report from SSC Satellitbild giving the Agency tentative and initial estimates of the potential cost and time-savings possible with the new proposed technology. The initial cost/benefit simulation will be further finalised in the following 'Implementation Blueprint' study. The general foundation and starting point for the cost/benefit calculation is to simulate a new efficient and relatively small 'imagery unit' within the IAEA, capable of performing advanced image processing as a tool for various safeguards tasks. The image processing capacity is suggested to be task- and interpretation-oriented. The study was performed over a period of 1,5 weeks in late 1998, and is based upon interviews of IAEA staff, reviews of existing IAEA documentation as well as from SSC Satellitbild's long-standing experience of satellite imagery and field missions. The cost/benefit analysis is based on a spreadsheet simulation of five potential applications of commercial satellite imagery: Reference information; Confirmation of Agency acquired and Member State supplied data; Change detection and on-going monitoring; Assessing open source information available to the Agency; Detecting undeclared activities and undeclared sites. The study confirms that the proposed concept of a relatively small 'imagery unit' using high-resolution data will be a sound and

The Matsu Wheel: A Cloud-Based Framework for Efficient Analysis and Reanalysis of Earth Satellite Imagery

Science.gov (United States)

Patterson, Maria T.; Anderson, Nicholas; Bennett, Collin; Bruggemann, Jacob; Grossman, Robert L.; Handy, Matthew; Ly, Vuong; Mandl, Daniel J.; Pederson, Shane; Pivarski, James;

Intuitive Tools for the Design and Analysis of Communication Payloads for Satellites

Science.gov (United States)

Culver, Michael R.; Soong, Christine; Warner, Joseph D.

2014-01-01

In an effort to make future communications satellite payload design more efficient and accessible, two tools were created with intuitive graphical user interfaces (GUIs). The first tool allows payload designers to graphically design their payload by using simple drag and drop of payload components onto a design area within the program. Information about each picked component is pulled from a database of common space-qualified communication components sold by commerical companies. Once a design is completed, various reports can be generated, such as the Master Equipment List. The second tool is a link budget calculator designed specifically for ease of use. Other features of this tool include being able to access a database of NASA ground based apertures for near Earth and Deep Space communication, the Tracking and Data Relay Satellite System (TDRSS) base apertures, and information about the solar system relevant to link budget calculations. The link budget tool allows for over 50 different combinations of user inputs, eliminating the need for multiple spreadsheets and the user errors associated with using them. Both of the aforementioned tools increase the productivity of space communication systems designers, and have the colloquial latitude to allow non-communication experts to design preliminary communication payloads.

Development of Mission and Spacecraft Dynamics Analysis System for Geostationary Communication Satellite

Directory of Open Access Journals (Sweden)

Hyeon Cheol Gong

1998-06-01

Full Text Available We consider the motion of the subsystems as separate bodies as well as the entire satellite for the attitude and orbit control of a communication satellite by multi-body modeling technique. Thus, the system can be applied to a general communication satellite as well as a specific communication satellite, i.e. Koreasat I, II. The simulation results can be viewed by two-dimensional graphics and three-dimensional animation. The graphical user interface (GUI makes its usage much simpler. We have simulated a couple of scenarios for Koreasat I, II which are being operated as geostationary communication satellites to verify the system performance.

Satellite image analysis and a hybrid ESSS/ANN model to forecast solar irradiance in the tropics

International Nuclear Information System (INIS)

Dong, Zibo; Yang, Dazhi; Reindl, Thomas; Walsh, Wilfred M.

2014-01-01

Highlights: • Satellite image analysis is performed and cloud cover index is classified using self-organizing maps (SOM). • The ESSS model is used to forecast cloud cover index. • Solar irradiance is estimated using multi-layer perceptron (MLP). • The proposed model shows better accuracy than other investigated models. - Abstract: We forecast hourly solar irradiance time series using satellite image analysis and a hybrid exponential smoothing state space (ESSS) model together with artificial neural networks (ANN). Since cloud cover is the major factor affecting solar irradiance, cloud detection and classification are crucial to forecast solar irradiance. Geostationary satellite images provide cloud information, allowing a cloud cover index to be derived and analysed using self-organizing maps (SOM). Owing to the stochastic nature of cloud generation in tropical regions, the ESSS model is used to forecast cloud cover index. Among different models applied in ANN, we favour the multi-layer perceptron (MLP) to derive solar irradiance based on the cloud cover index. This hybrid model has been used to forecast hourly solar irradiance in Singapore and the technique is found to outperform traditional forecasting models

Analysis of Standards Efficiency in Digital Television Via Satellite at Ku and Ka Bands

Directory of Open Access Journals (Sweden)

Landeros-Ayala Salvador

2013-06-01

Full Text Available In this paper, an analysis on the main technical features of digital television standards for satellite transmission is carried out. Based on simulations and link budgets, the standard with the best operational performance is defined, based on simulations and link budget analysis, as well as a comparative efficiency analysis is conducted for the Ku and Ka bands for both transparent and regenerative transponders in terms of power, bandwidth, information rate and link margin, including clear sky, uplink rain, downlink rain and rain in both.

Satellite Contamination and Materials Outgassing Knowledge base

Science.gov (United States)

Minor, Jody L.; Kauffman, William J. (Technical Monitor)

2001-01-01

Satellite contamination continues to be a design problem that engineers must take into account when developing new satellites. To help with this issue, NASA's Space Environments and Effects (SEE) Program funded the development of the Satellite Contamination and Materials Outgassing Knowledge base. This engineering tool brings together in one location information about the outgassing properties of aerospace materials based upon ground-testing data, the effects of outgassing that has been observed during flight and measurements of the contamination environment by on-orbit instruments. The knowledge base contains information using the ASTM Standard E- 1559 and also consolidates data from missions using quartz-crystal microbalances (QCM's). The data contained in the knowledge base was shared with NASA by government agencies and industry in the US and international space agencies as well. The term 'knowledgebase' was used because so much information and capability was brought together in one comprehensive engineering design tool. It is the SEE Program's intent to continually add additional material contamination data as it becomes available - creating a dynamic tool whose value to the user is ever increasing. The SEE Program firmly believes that NASA, and ultimately the entire contamination user community, will greatly benefit from this new engineering tool and highly encourages the community to not only use the tool but add data to it as well.

Satellite and ground-based sensors for the Urban Heat Island analysis in the city of Rome

DEFF Research Database (Denmark)

Fabrizi, Roberto; Bonafoni, Stefania; Biondi, Riccardo

2010-01-01

In this work, the trend of the Urban Heat Island (UHI) of Rome is analyzed by both ground-based weather stations and a satellite-based infrared sensor. First, we have developed a suitable algorithm employing satellite brightness temperatures for the estimation of the air temperature belonging...... and nighttime scenes taken between 2003 and 2006 have been processed. Analysis of the Canopy Layer Heat Island (CLHI) during summer months reveals a mean growth in magnitude of 3-4 K during nighttime and a negative or almost zero CLHI intensity during daytime, confirmed by the weather stations. © 2010...... by the authors; licensee MDPI, Basel, Switzerland. Keyword: Thermal pollution,Summer months,Advanced-along track scanning radiometers,Urban heat island,Remote sensing,Canopy layer,Atmospheric temperature,Ground based sensors,Weather information services,Satellite remote sensing,Infra-red sensor,Weather stations...

Analysis of satellite-derived solar irradiance over the Netherlands

Science.gov (United States)

Dirksen, Marieke; Fokke Meirink, Jan; Sluiter, Raymond

2017-04-01

Measurements from geostationary satellites allow the retrieval of surface solar irradiance homogeneously over large areas, thereby providing essential information for the solar energy sector. In this paper, the SICCS solar irradiance data record derived from 12 years of Meteosat Second Generation satellite measurements is analysed with a focus on the Netherlands, where the spatial resolution is about 6 by 3 km2. Extensive validation of the SICCS data with pyranometer observations is performed, indicating a bias of approximately 3 W/m2 and RMSE of 11 W/m2 for daily data. Long term averages and seasonal variations of solar irradiance show regional patterns related to the surface type (e.g., coastal waters, forests, cities). The inter-annual variability over the time frame of the data record is quantified. Methods to merge satellite and surface observations into an optimized data record are explored.

Optimization and Feasibility Analysis of Satellite Earth Station Power System Using Homer

Directory of Open Access Journals (Sweden)

Hassen T. Dorrah

2012-06-01

Full Text Available Satellite earth stations which located in remote areas are one of many applications powered by the renewable energy sources. Ground system consists of ground station and control centers working together to support the spacecraft and the data user. Earth station consists of major subsystems, transmitter, receiver, antenna, tracking equipment, terrestrial interface equipment and power supply. Power subsystem is an important part that required for supplying the earth station with electrical power to continue communicating with its remote sensing satellite. This paper deals with simulation and optimal sizing of earth station power system using HOMER software. A combination of two energy sources (solar, and wind to provide a continuous electric power production is used to determine the optimum system operation. Three system configurations are compared with respect to the total net present cost (NPC and levelized cost of energy (COE. Also, economical study will be analyzed for energy demand and sensitivity analysis will be performed.

Rainfall frequency analysis for ungauged sites using satellite precipitation products

Science.gov (United States)

Gado, Tamer A.; Hsu, Kuolin; Sorooshian, Soroosh

2017-11-01

The occurrence of extreme rainfall events and their impacts on hydrologic systems and society are critical considerations in the design and management of a large number of water resources projects. As precipitation records are often limited or unavailable at many sites, it is essential to develop better methods for regional estimation of extreme rainfall at these partially-gauged or ungauged sites. In this study, an innovative method for regional rainfall frequency analysis for ungauged sites is presented. The new method (hereafter, this is called the RRFA-S) is based on corrected annual maximum series obtained from a satellite precipitation product (e.g., PERSIANN-CDR). The probability matching method (PMM) is used here for bias correction to match the CDF of satellite-based precipitation data with the gauged data. The RRFA-S method was assessed through a comparative study with the traditional index flood method using the available annual maximum series of daily rainfall in two different regions in USA (11 sites in Colorado and 18 sites in California). The leave-one-out cross-validation technique was used to represent the ungauged site condition. Results of this numerical application have found that the quantile estimates obtained from the new approach are more accurate and more robust than those given by the traditional index flood method.

DATA MANAGEMENT SYSTEM FOR MOBILE SATELLITE PROPAGATION DATA

Science.gov (United States)

Kantak, A. V.

1994-01-01

The "Data Management System for Mobile Satellite Propogation" package is a collection of FORTRAN programs and UNIX shell scripts designed to handle the huge amounts of data resulting from Mobile Satellite propogation experiments. These experiments are designed to assist in defining channels for mobile satellite systems. By understanding multipath fading characteristics of the channel, doppler effects, and blockage due to manmade objects as well as natural surroundings, characterization of the channel can be realized. Propogation experiments, then, are performed using a prototype of the system simulating the ultimate product environment. After the data from these experiments is generated, the researcher must access this data with a minimum of effort and to derive some standard results. The programs included in this package manipulate the data files generated by the NASA/JPL Mobile Satellite propogation experiment on an interactive basis. In the experiment, a transmitter operating at 869 MHz was carried to an altitude of 32Km by a stratospheric balloon. A vehicle within the line-of-sight of the transmitter was then driven around, splitting the incoming signal into I and Q channels, and sampling the resulting signal strength at 1000 samples per second. The data was collected at various antenna elavation angles and different times of day generating the ancillary data for the experiment. This package contains a program to convert the binary format of the data generated into standard ASCII format suitable for use with a wide variety of machine architectures. Also included is a UNIX shell-script designed to parse this ASCII file into those records of data that match the researcher's desired values for the ancillary data parameters. In addition, four FORTRAN programs are included to obtain standard quantities from the data. Quantities such as probability of signal level greater than or equal to a specified signal level, probability density of the signal levels, frequency

Error analysis of satellite attitude determination using a vision-based approach

Science.gov (United States)

Carozza, Ludovico; Bevilacqua, Alessandro

2013-09-01

Improvements in communication and processing technologies have opened the doors to exploit on-board cameras to compute objects' spatial attitude using only the visual information from sequences of remote sensed images. The strategies and the algorithmic approach used to extract such information affect the estimation accuracy of the three-axis orientation of the object. This work presents a method for analyzing the most relevant error sources, including numerical ones, possible drift effects and their influence on the overall accuracy, referring to vision-based approaches. The method in particular focuses on the analysis of the image registration algorithm, carried out through on-purpose simulations. The overall accuracy has been assessed on a challenging case study, for which accuracy represents the fundamental requirement. In particular, attitude determination has been analyzed for small satellites, by comparing theoretical findings to metric results from simulations on realistic ground-truth data. Significant laboratory experiments, using a numerical control unit, have further confirmed the outcome. We believe that our analysis approach, as well as our findings in terms of error characterization, can be useful at proof-of-concept design and planning levels, since they emphasize the main sources of error for visual based approaches employed for satellite attitude estimation. Nevertheless, the approach we present is also of general interest for all the affine applicative domains which require an accurate estimation of three-dimensional orientation parameters (i.e., robotics, airborne stabilization).

SDI satellite autonomy using AI and Ada

Science.gov (United States)

Fiala, Harvey E.

1990-01-01

The use of Artificial Intelligence (AI) and the programming language Ada to help a satellite recover from selected failures that could lead to mission failure are described. An unmanned satellite will have a separate AI subsystem running in parallel with the normal satellite subsystems. A satellite monitoring subsystem (SMS), under the control of a blackboard system, will continuously monitor selected satellite subsystems to become alert to any actual or potential problems. In the case of loss of communications with the earth or the home base, the satellite will go into a survival mode to reestablish communications with the earth. The use of an AI subsystem in this manner would have avoided the tragic loss of the two recent Soviet probes that were sent to investigate the planet Mars and its moons. The blackboard system works in conjunction with an SMS and a reconfiguration control subsystem (RCS). It can be shown to be an effective way for one central control subsystem to monitor and coordinate the activities and loads of many interacting subsystems that may or may not contain redundant and/or fault-tolerant elements. The blackboard system will be coded in Ada using tools such as the ABLE development system and the Ada Production system.

IAEA Safeguards: Cost/benefit analysis of commercial satellite imagery

Energy Technology Data Exchange (ETDEWEB)

Andersson, Christer [SSC Satellitbild AB, Kiruna (Sweden)

1999-03-01

A major milestone in the efforts to strengthen the Safeguards System was reached in May 1997 when the Board of Governors approved a `Model Protocol Additional to Safeguards Agreements`. The Protocol provides the legal basis necessary to enhance the Agency`s ability to detect undeclared nuclear material and activities by using information available from open sources to complement the declarations made by Member States. Commercially available high-resolution satellite data has emerged as one potential complementary open information source to support the traditional and extended Safeguard activities of IAEA. This document constitutes a first report from SSC Satellitbild giving the Agency tentative and initial estimates of the potential cost and time-savings possible with the new proposed technology. The initial cost/benefit simulation will be further finalised in the following `Implementation Blueprint` study. The general foundation and starting point for the cost/benefit calculation is to simulate a new efficient and relatively small `imagery unit` within the IAEA, capable of performing advanced image processing as a tool for various safeguards tasks. The image processing capacity is suggested to be task- and interpretation-oriented. The study was performed over a period of 1,5 weeks in late 1998, and is based upon interviews of IAEA staff, reviews of existing IAEA documentation as well as from SSC Satellitbild`s long-standing experience of satellite imagery and field missions. The cost/benefit analysis is based on a spreadsheet simulation of five potential applications of commercial satellite imagery: Reference information; Confirmation of Agency acquired and Member State supplied data; Change detection and on-going monitoring; Assessing open source information available to the Agency; Detecting undeclared activities and undeclared sites. The study confirms that the proposed concept of a relatively small `imagery unit` using high-resolution data will be a sound and

SOFT project: a new forecasting system based on satellite data

Science.gov (United States)

Pascual, Ananda; Orfila, A.; Alvarez, Alberto; Hernandez, E.; Gomis, D.; Barth, Alexander; Tintore, Joaquim

2002-01-01

The aim of the SOFT project is to develop a new ocean forecasting system by using a combination of satellite dat, evolutionary programming and numerical ocean models. To achieve this objective two steps are proved: (1) to obtain an accurate ocean forecasting system using genetic algorithms based on satellite data; and (2) to integrate the above new system into existing deterministic numerical models. Evolutionary programming will be employed to build 'intelligent' systems that, learning form the past ocean variability and considering the present ocean state, will be able to infer near future ocean conditions. Validation of the forecast skill will be carried out by comparing the forecasts fields with satellite and in situ observations. Validation with satellite observations will provide the expected errors in the forecasting system. Validation with in situ data will indicate the capabilities of the satellite based forecast information to improve the performance of the numerical ocean models. This later validation will be accomplished considering in situ measurements in a specific oceanographic area at two different periods of time. The first set of observations will be employed to feed the hybrid systems while the second set will be used to validate the hybrid and traditional numerical model results.

A decentralized design philosophy for satellites

DEFF Research Database (Denmark)

Nielsen, Jens Frederik Dalsgaard; Larsen, Jesper Abildgaard

2011-01-01

For the last decade development and construction of student cubesat satellites has played an important part in the engineering Master Program within Electrical Engineering and Information Technology at Aalborg University, Denmark. As a result three cubesats AAU CUBESAT, AAUSAT-II and AAUSAT3 has ...

New Methods for Air Quality Model Evaluation with Satellite Data

Science.gov (United States)

Holloway, T.; Harkey, M.

2015-12-01

Despite major advances in the ability of satellites to detect gases and aerosols in the atmosphere, there remains significant, untapped potential to apply space-based data to air quality regulatory applications. Here, we showcase research findings geared toward increasing the relevance of satellite data to support operational air quality management, focused on model evaluation. Particular emphasis is given to nitrogen dioxide (NO2) and formaldehyde (HCHO) from the Ozone Monitoring Instrument aboard the NASA Aura satellite, and evaluation of simulations from the EPA Community Multiscale Air Quality (CMAQ) model. This work is part of the NASA Air Quality Applied Sciences Team (AQAST), and is motivated by ongoing dialog with state and federal air quality management agencies. We present the response of satellite-derived NO2 to meteorological conditions, satellite-derived HCHO:NO2 ratios as an indicator of ozone production regime, and the ability of models to capture these sensitivities over the continental U.S. In the case of NO2-weather sensitivities, we find boundary layer height, wind speed, temperature, and relative humidity to be the most important variables in determining near-surface NO2 variability. CMAQ agreed with relationships observed in satellite data, as well as in ground-based data, over most regions. However, we find that the southwest U.S. is a problem area for CMAQ, where modeled NO2 responses to insolation, boundary layer height, and other variables are at odds with the observations. Our analyses utilize a software developed by our team, the Wisconsin Horizontal Interpolation Program for Satellites (WHIPS): a free, open-source program designed to make satellite-derived air quality data more usable. WHIPS interpolates level 2 satellite retrievals onto a user-defined fixed grid, in effect creating custom-gridded level 3 satellite product. Currently, WHIPS can process the following data products: OMI NO2 (NASA retrieval); OMI NO2 (KNMI retrieval); OMI

Analysis and Validation of ZY-3 02 Satellite Laser Altimetry Data

Directory of Open Access Journals (Sweden)

LI Guoyuan

2017-12-01

Full Text Available ZY-3 02 satellite loaded with Chinese first earth observing satellite laser altimeter,and has been launched successfully on 30th May,2016. In this paper,the theoretical accuracy of the laser altimeter is analyzed,and several experimental areas are used to verify the actual accuracy. At the same time,the application of the laser altimetry data in the field of space-borne photogrammetry is tested. The laser altimetry theoretical accuracy of ZY-3 02 satellite in the flat area (slope less than 2 degrees is about 0.85 m and 14.2 m in the elevation and planimetry direction,respectively. The effective laser altimetry data account for about 23.89%,and near the calibration field the elevation accuracy is 0.89 m,and planimetry accuracy is about 14.76 m. Moreover,the verified elevation accuracy is 1.09 m in the North China by high precision DSM terrain data,and laser footprint points accuracy on the surface of the Bohai inland sea is about 0.47 m. When the laser foot print point is used as elevation control point,the elevation accuracy of the ZY-3 02 satellite stereo images in Shaanxi Weinan can be increased from 11.54 m to 1.90 m without GCPs. Although ZY3-02 satellite laser altimeter is just a test,the results proved that the domestic satellite laser altimetry data can effectively improve the stereo images without GCPs,which will be valuable in the global mapping project. It is suggest that operational laser altimeter equip on the next satellite of ZY-3 serials.

Automated tracking for advanced satellite laser ranging systems

Science.gov (United States)

McGarry, Jan F.; Degnan, John J.; Titterton, Paul J., Sr.; Sweeney, Harold E.; Conklin, Brion P.; Dunn, Peter J.

1996-06-01

NASA's Satellite Laser Ranging Network was originally developed during the 1970's to track satellites carrying corner cube reflectors. Today eight NASA systems, achieving millimeter ranging precision, are part of a global network of more than 40 stations that track 17 international satellites. To meet the tracking demands of a steadily growing satellite constellation within existing resources, NASA is embarking on a major automation program. While manpower on the current systems will be reduced to a single operator, the fully automated SLR2000 system is being designed to operate for months without human intervention. Because SLR2000 must be eyesafe and operate in daylight, tracking is often performed in a low probability of detection and high noise environment. The goal is to automatically select the satellite, setup the tracking and ranging hardware, verify acquisition, and close the tracking loop to optimize data yield. TO accomplish the autotracking tasks, we are investigating (1) improved satellite force models, (2) more frequent updates of orbital ephemerides, (3) lunar laser ranging data processing techniques to distinguish satellite returns from noise, and (4) angular detection and search techniques to acquire the satellite. A Monte Carlo simulator has been developed to allow optimization of the autotracking algorithms by modeling the relevant system errors and then checking performance against system truth. A combination of simulator and preliminary field results will be presented.

Satellite and Ground-Based Sensors for the Urban Heat Island Analysis in the City of Rome

Directory of Open Access Journals (Sweden)

Roberto Fabrizi

2010-05-01

Full Text Available In this work, the trend of the Urban Heat Island (UHI of Rome is analyzed by both ground-based weather stations and a satellite-based infrared sensor. First, we have developed a suitable algorithm employing satellite brightness temperatures for the estimation of the air temperature belonging to the layer of air closest to the surface. UHI spatial characteristics have been assessed using air temperatures measured by both weather stations and brightness temperature maps from the Advanced Along Track Scanning Radiometer (AATSR on board ENVISAT polar-orbiting satellite. In total, 634 daytime and nighttime scenes taken between 2003 and 2006 have been processed. Analysis of the Canopy Layer Heat Island (CLHI during summer months reveals a mean growth in magnitude of 3–4 K during nighttime and a negative or almost zero CLHI intensity during daytime, confirmed by the weather stations.

Satellite images to aircraft in flight. [GEOS image transmission feasibility analysis

Science.gov (United States)

Camp, D.; Luers, J. K.; Kadlec, P. W.

1977-01-01

A study has been initiated to evaluate the feasibility of transmitting selected GOES images to aircraft in flight. Pertinent observations that could be made from satellite images on board aircraft include jet stream activity, cloud/wind motion, cloud temperatures, tropical storm activity, and location of severe weather. The basic features of the Satellite Aircraft Flight Environment System (SAFES) are described. This system uses East GOES and West GOES satellite images, which are interpreted, enhanced, and then retransmitted to designated aircraft.

Near-equatorial convective regimes over the Indian Ocean as revealed by synergistic analysis of satellite observations.

Digital Repository Service at National Institute of Oceanography (India)

Levy, G.; Geiss, A.; RameshKumar, M.R.

We examine the organization and temporal evolution of deep convection in relation to the low level flow over the Indian Ocean by a synergistic analysis of several satellite datasets for wind, rainfall, Outgoing Longwave Radiation (OLR) and cloud...

Satellite Remote Sensing in Seismology. A Review

Directory of Open Access Journals (Sweden)

Andrew A. Tronin

2009-12-01

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.

Ganga floods of 2010 in Uttar Pradesh, north India: a perspective analysis using satellite remote sensing data

Directory of Open Access Journals (Sweden)

C.M. Bhatt

2016-03-01

Full Text Available The present study focuses on the unprecedented flood situation captured through multi-temporal satellite images, witnessed along the Ganga River in Uttar Pradesh during September 2010. At three gauge stations (Kannauj, Ankinghat and Kanpur, river water level exceeded the previous high-flood level attained by river more than a decade ago. The present communication with the aid of pre- and post-flood satellite images, coupled with hydrological (river water level and meteorological (rainfall data, explains about the unprecedented flood situation. In the latter part of the study, a novel and cost-effective method for building a library of flood inundation extents based on historical satellite data analysis and tagging the inundation layer with observed water level is demonstrated. During flood season, based on the forecasted water level, the library can be accessed to fetch the spatial inundation layer corresponding to the forecasted stage and anticipate in advance, likely spatial inundation pattern and submergence of villages and hence in alerting the habitation at risk. This method can be helpful in anticipating the areas to be affected in situations where satellite images cannot be effectively utilized due to cloud cover and also for providing information about the areas being partially covered in satellite data.

Advanced Analysis of the Influence of Clouds, Precipiation and Surface Emissivity on DMSP/NPOESS Satellite Microwave Channels

National Research Council Canada - National Science Library

Isaacs, R

2002-01-01

...: development of databases of brightness temperatures from various satellite sensors; development databases of conventional analysis to verify the presence and amount of clouds and precipitation and for verification of retrieval results...

Analysis of Errors in a Special Perturbations Satellite Orbit Propagator

Energy Technology Data Exchange (ETDEWEB)

Beckerman, M.; Jones, J.P.

1999-02-01

We performed an analysis of error densities for the Special Perturbations orbit propagator using data for 29 satellites in orbits of interest to Space Shuttle and International Space Station collision avoidance. We find that the along-track errors predominate. These errors increase monotonically over each 36-hour prediction interval. The predicted positions in the along-track direction progressively either leap ahead of or lag behind the actual positions. Unlike the along-track errors the radial and cross-track errors oscillate about their nearly zero mean values. As the number of observations per fit interval decline the along-track prediction errors, and amplitudes of the radial and cross-track errors, increase.

Network Configuration Analysis for Formation Flying Satellites

Science.gov (United States)

Knoblock, Eric J.; Wallett, Thomas M.; Konangi, Vijay K.; Bhasin, Kul B.

2001-01-01

The performance of two networks to support autonomous multi-spacecraft formation flying systems is presented. Both systems are comprised of a ten-satellite formation, with one of the satellites designated as the central or 'mother ship.' All data is routed through the mother ship to the terrestrial network. The first system uses a TCP/EP over ATM protocol architecture within the formation, and the second system uses the IEEE 802.11 protocol architecture within the formation. The simulations consist of file transfers using either the File Transfer Protocol (FTP) or the Simple Automatic File Exchange (SAFE) Protocol. The results compare the IP queuing delay, IP queue size and IP processing delay at the mother ship as well as end-to-end delay for both systems. In all cases, using IEEE 802.11 within the formation yields less delay. Also, the throughput exhibited by SAFE is better than FTP.

Infrared Methods for Daylight Acquisition of LEO Satellites

National Research Council Canada - National Science Library

Nelson, Joel

2004-01-01

..., and very capable space surveillance systems. The first product of the Raven program was a family of telescopes capable of generating world-class optical observation data of deep-space satellites...

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

Science.gov (United States)

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

2004-01-01

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 (trmm.gsfc.nasa.gov) 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.

Small satellites and space debris issues

Science.gov (United States)

Yakovlev, M.; Kulik, S.; Agapov, V.

2001-10-01

The objective of this report is the analysis of the tendencies in designing of small satellites (SS) and the effect of small satellites on space debris population. It is shown that SS to include nano- and pico-satellites should be considered as a particularly dangerous source of space debris when elaborating international standards and legal documents concerning the space debris problem, in particular "International Space Debris Mitigation Standard". These issues are in accordance with the IADC goals in its main activity areas and should be carefully considered within the IADC framework.

Software for validating parameters retrieved from satellite

Digital Repository Service at National Institute of Oceanography (India)

Muraleedharan, P.M.; Sathe, P.V.; Pankajakshan, T.

-channel Scanning Microwave Radiometer (MSMR) onboard the Indian satellites Occansat-1 during 1999-2001 were validated using this software as a case study. The program has several added advantages over the conventional method of validation that involves strenuous...

First satellite mobile communication trials using BLQS-CDMA

Science.gov (United States)

Luzdemateo, Maria; Johns, Simon; Dothey, Michel; Vanhimbeeck, Carl; Deman, Ivan; Wery, Bruno

1993-01-01

In this paper, technical results obtained in the first MSBN Land mobile technical trial are reported. MSBN (Mobile Satellite Business Network) is a new program undertaken by the European Space Agency (ESA) to promote mobile satellite communication in Europe, in particular voice capability. The first phase of the MSBN system implementation plan is an experimental phase. Its purpose is to evaluate through field experiments the performance of the MSBN system prior to finalization of its specifications. Particularly, the objective is to verify in the field and possibly improve the performance of the novel satellite access technique BLQS-CDMA (Band Limited Quasi-Synchronous-Code Division Multiple Access), which is proposed as baseline for the MSBN.

Analysis of the influence of orbital disturbances applied to an artificial lunar satellite

International Nuclear Information System (INIS)

Gonçalves, L D; Rocco, E M; De Moraes, R V

2015-01-01

This paper analyzes the influence of the orbital disturbance forces in the trajectory of lunar satellites. The following gravitational and non-gravitational orbital disturbances are considered: the non-homogeneity of the lunar gravitational field; the gravitational attraction due to the third body, considering the Earth and the Sun; the lunar albedo; the solar radiation pressure. Numerical models were developed and implemented in an orbital trajectory simulator aiming to understand the dynamics of the orbital motion of an artificial satellite in lunar orbit when considering the simultaneous effect of all disturbances. Different orbits were simulated in order to characterize the major and the minor influence of each disturbing force as function of the inclination and the right ascension of the ascending node. This study can be very useful in the space mission analysis and in the selection of orbits less affected by environmental disturbances. (paper)

Active Fire Mapping Program

Science.gov (United States)

Active Fire Mapping Program Current Large Incidents (Home) New Large Incidents Fire Detection Maps MODIS Satellite Imagery VIIRS Satellite Imagery Fire Detection GIS Data Fire Data in Google Earth ...

ESTIMATING RELIABILITY OF DISTURBANCES IN SATELLITE TIME SERIES DATA BASED ON STATISTICAL ANALYSIS

Directory of Open Access Journals (Sweden)

Z.-G. Zhou

2016-06-01

Full Text Available Normally, the status of land cover is inherently dynamic and changing continuously on temporal scale. However, disturbances or abnormal changes of land cover — caused by such as forest fire, flood, deforestation, and plant diseases — occur worldwide at unknown times and locations. Timely detection and characterization of these disturbances is of importance for land cover monitoring. Recently, many time-series-analysis methods have been developed for near real-time or online disturbance detection, using satellite image time series. However, the detection results were only labelled with “Change/ No change” by most of the present methods, while few methods focus on estimating reliability (or confidence level of the detected disturbances in image time series. To this end, this paper propose a statistical analysis method for estimating reliability of disturbances in new available remote sensing image time series, through analysis of full temporal information laid in time series data. The method consists of three main steps. (1 Segmenting and modelling of historical time series data based on Breaks for Additive Seasonal and Trend (BFAST. (2 Forecasting and detecting disturbances in new time series data. (3 Estimating reliability of each detected disturbance using statistical analysis based on Confidence Interval (CI and Confidence Levels (CL. The method was validated by estimating reliability of disturbance regions caused by a recent severe flooding occurred around the border of Russia and China. Results demonstrated that the method can estimate reliability of disturbances detected in satellite image with estimation error less than 5% and overall accuracy up to 90%.

Analysis of Patient Visits and Collections After Opening a Satellite Pediatric Emergency Department.

Science.gov (United States)

Nichols, Katherine M; Caperell, Kerry; Cross, Keith; Duncan, Scott; Foster, Ben; Liu, Gil; Pritchard, Hank; Southard, Gary; Shinabery, Ben; Sutton, Brad; Kim, In K

2018-04-01

Satellite pediatric emergency departments (PEDs) have emerged as a strategy to increase patient capacity. We sought to determine the impact on patient visits, physician fee collections, and value of emergency department (ED) time at the primary PED after opening a nearby satellite PED. We also illustrate the spatial distribution of patient demographics and overlapping catchment areas for the primary and satellite PEDs using geographical information system. A structured, financial retrospective review was conducted. Aggregate patient demographic data and billing data were collected regarding physician fee charges, collections, and patient visits for both PEDs. All ED visits from January 2009 to December 2013 were analyzed. Geographical information system mapping using ArcGIS mapped ED patient visits. Patient visits at the primary PED were 53,050 in 2009 before the satellite PED opened. The primary PED visits increased after opening the satellite PED to 55,932 in 2013. The satellite PED visits increased to 21,590 in 2013. Collections per visit at the primary PED decreased from $105.13 per visit in 2011 to $86.91 per visit in 2013. Total collections at the satellite PED decreased per visit from $155.41 per visit in 2011 to $128.53 per visit in 2013. After opening a nearby satellite PED, patient visits at the primary PED did not substantially decrease, suggesting that there was a previously unrecognized demand for PED services. The collections per ED visit were greater at the satellite ED, likely due to a higher collection rate.

NASA/MSFC FY90 Global Scale Atmospheric Processes Research Program Review

Science.gov (United States)

Leslie, Fred W. (Editor)

1990-01-01

Research supported by the Global Atmospheric Research Program at the Marshall Space Flight Center on atmospheric remote sensing, meteorology, numerical weather forecasting, satellite data analysis, cloud precipitation, atmospheric circulation, atmospheric models and related topics is discussed.

Saturn satellites

International Nuclear Information System (INIS)

Ruskol, E.L.

1981-01-01

The characteristics of the Saturn satellites are discussed. The satellites close to Saturn - Janus, Mimas, Enceladus, Tethys, Dione and Rhea - rotate along the circular orbits. High reflectivity is attributed to them, and the density of the satellites is 1 g/cm 3 . Titan is one of the biggest Saturn satellites. Titan has atmosphere many times more powerful than that of Mars. The Titan atmosphere is a peculiar medium with a unique methane and hydrogen distribution in the whole Solar system. The external satellites - Hyperion, Japetus and Phoebe - are poorly investigated. Neither satellite substance density, nor their composition are known. The experimental data on the Saturn rings obtained on the ''Pioneer-11'' and ''Voyager-1'' satellites are presented [ru

Image Positioning Accuracy Analysis for Super Low Altitude Remote Sensing Satellites

Directory of Open Access Journals (Sweden)

Ming Xu

2012-10-01

Full Text Available Super low altitude remote sensing satellites maintain lower flight altitudes by means of ion propulsion in order to improve image resolution and positioning accuracy. The use of engineering data in design for achieving image positioning accuracy is discussed in this paper based on the principles of the photogrammetry theory. The exact line-of-sight rebuilding of each detection element and this direction precisely intersecting with the Earth's elliptical when the camera on the satellite is imaging are both ensured by the combined design of key parameters. These parameters include: orbit determination accuracy, attitude determination accuracy, camera exposure time, accurately synchronizing the reception of ephemeris with attitude data, geometric calibration and precise orbit verification. Precise simulation calculations show that image positioning accuracy of super low altitude remote sensing satellites is not obviously improved. The attitude determination error of a satellite still restricts its positioning accuracy.

Antennas for mobile satellite communications

Science.gov (United States)

Huang, John

1991-12-01

A NASA sponsored program, called the Mobile Satellite (MSAT) system, has prompted the development of several innovative antennas at L-band frequencies. In the space segment of the MSAT system, an efficient, light weight, circularly polarized microstrip array that uses linearly polarized elements was developed as a multiple beam reflector feed system. In the ground segment, a low-cost, low-profile, and very efficient microstrip Yagi array was developed as a medium-gain mechanically steered vehicle antenna. Circularly shaped microstrip patches excited at higher-order modes were also developed as low-gain vehicle antennas. A more recent effort called for the development of a 20/30 GHz mobile terminal antenna for future-generation mobile satellite communications. To combat the high insertion loss encountered at 20/30 GHz, series-fed Monolithic Microwave Integrated Circuit (MMIC) microstrip array antennas are currently being developed. These MMIC arrays may lead to the development of several small but high-gain Ka-band antennas for the Personal Access Satellite Service planned for the 2000s.

Simulation and Analysis of Autonomous Time Synchronization Based on Asynchronism Two-way Inter-satellite Link

Science.gov (United States)

Fang, L.; Yang, X. H.; Sun, B. Q.; Qin, W. J.; Kong, Y.

2013-09-01

The measurement of the inter-satellite link is one of the key techniques in the autonomous operation of satellite navigation system. Based on the asynchronism inter-satellite two-way measurement mode in GPS constellation, the reduction formula of the inter-satellite time synchronization is built in this paper. Moreover, the corrective method of main systematic errors is proposed. Inter-satellite two-way time synchronization is simulated on the basis of IGS (International GNSS Service) precise ephemeris. The impacts of the epoch domestication of asynchronism inter-satellite link pseudo-range, the initial orbit, and the main systematic errors on satellite time synchronization are analyzed. Furthermore, the broadcast clock error of each satellite is calculated by the ``centralized'' inter-satellite autonomous time synchronization. Simulation results show that the epoch domestication of asynchronism inter-satellite link pseudo-range and the initial orbit have little impact on the satellite clock errors, and thus they needn't be taken into account. The errors caused by the relativistic effect and the asymmetry of path travel have large impact on the satellite clock errors. These should be corrected with theoretical formula. Compared with the IGS precise clock error, the root mean square of the broadcast clock error of each satellite is about 0.4 ns.

Performance Analysis of an Enhanced PRMA-HS Protocol for LEO Satellite Communication

Institute of Scientific and Technical Information of China (English)

ZHUO Yong-ning; YAN Shao-hu; WU Shi-qi

2005-01-01

The packet reservation multiple access with hindering state (PRMA-HS) is a protocol suitable for LEO satellite mobile communication. Although working well with light system payload (amount of user terminals), the protocol imposes high channel congestion on system with heavy payload, thus degrades the system's quality of service. To controlling the channel congestion, a scheme of enhanced PRMA-HS protocol is proposed, which aims to reduce the collision of voice packets by adopting a mechanism of access control. Through theoretic analysis, the system's mathematic model is presented and the packet drop probability of the scheme is deduced. To testify the performance of the scheme, a simulation is performed and the results support our analysis.

Analysis of smear in high-resolution remote sensing satellites

Science.gov (United States)

Wahballah, Walid A.; Bazan, Taher M.; El-Tohamy, Fawzy; Fathy, Mahmoud

2016-10-01

High-resolution remote sensing satellites (HRRSS) that use time delay and integration (TDI) CCDs have the potential to introduce large amounts of image smear. Clocking and velocity mismatch smear are two of the key factors in inducing image smear. Clocking smear is caused by the discrete manner in which the charge is clocked in the TDI-CCDs. The relative motion between the HRRSS and the observed object obliges that the image motion velocity must be strictly synchronized with the velocity of the charge packet transfer (line rate) throughout the integration time. During imaging an object off-nadir, the image motion velocity changes resulting in asynchronization between the image velocity and the CCD's line rate. A Model for estimating the image motion velocity in HRRSS is derived. The influence of this velocity mismatch combined with clocking smear on the modulation transfer function (MTF) is investigated by using Matlab simulation. The analysis is performed for cross-track and along-track imaging with different satellite attitude angles and TDI steps. The results reveal that the velocity mismatch ratio and the number of TDI steps have a serious impact on the smear MTF; a velocity mismatch ratio of 2% degrades the MTFsmear by 32% at Nyquist frequency when the TDI steps change from 32 to 96. In addition, the results show that to achieve the requirement of MTFsmear >= 0.95 , for TDI steps of 16 and 64, the allowable roll angles are 13.7° and 6.85° and the permissible pitch angles are no more than 9.6° and 4.8°, respectively.

Satellite Power System (SPS) Program Summary

Energy Technology Data Exchange (ETDEWEB)

1978-12-01

The joint DOE/NASA SPS program has as its objective to achieve by the end of 1980 an initial understanding of the technical feasibility, economic practicability, and the social and environmental acceptability of the SPS concepts so that recommendations concerning program continuation can be made. The four major study areas include (1) systems definition; (2) environmental assessment; (3) societal assessment; and (4) comparative assessment of alternative energy systems. All the projects on the SPS program are listed and summarized for FY 1978. (WHK)

Satellite Radiothermovision on Synoptic and Climatically Significant Scales

Science.gov (United States)

Ermakov, D. M.; Sharkov, E. A.; Chernushich, A. P.

2017-12-01

This paper is focused on the development of a methodological basis for the authors' approach to the processing of large volumes of satellite radiothermal data, which is known as satellite radiothermovision. A closed scheme for calculating the latent heat flux (and other integral characteristics of the dynamics of geophysical fields) through arbitrary contours (boundaries) has been constructed and mathematically described. The opportunity for working with static, as well as movable and deformable boundaries of arbitrary shape, has been provided. The computational scheme was tested using the example of calculations of the atmospheric advection of the latent heat from the North Atlantics to the Arctic in 2014. Preliminary analysis of the results showed a high potential of the approach when applying it to the study of a wide range of synoptic and climatically significant atmospheric processes of the Earth. Some areas for the further development of the satellite radiothermovision approach are briefly discussed. It is noted that expanding the analysis of the available satellite data to as much data as possible is of considerable importance. Among the immediate prospects is the analysis of large arrays of data already accumulated and processed in terms of the satellite radiothermovision ideology, which are partially presented and continuously updated on a specialized geoportal.

The 30/20 GHz experimental communications satellite system

Science.gov (United States)

Sivo, J. N.

NASA is continuing to pursue an agressive satellite communications technology development program focused on the 30/20 GHz frequency band. A review of the program progress to date is presented. Included is a discussion of the technology program status as well as a description of the experimental system concept under study. Expected system performance characteristics together with spacecraft and payload configuration details including weight and power budget is presented. Overall program schedules of both the technology development and the flight system development are included.

Access NASA Satellite Global Precipitation Data Visualization on YouTube

Science.gov (United States)

Liu, Z.; Su, J.; Acker, J. G.; Huffman, G. J.; Vollmer, B.; Wei, J.; Meyer, D. J.

2017-12-01

Since the satellite era began, NASA has collected a large volume of Earth science observations for research and applications around the world. Satellite data at 12 NASA data centers can also be used for STEM activities such as disaster events, climate change, etc. However, accessing satellite data can be a daunting task for non-professional users such as teachers and students because of unfamiliarity of terminology, disciplines, data formats, data structures, computing resources, processing software, programing languages, etc. Over the years, many efforts have been developed to improve satellite data access, but barriers still exist for non-professionals. In this presentation, we will present our latest activity that uses the popular online video sharing web site, YouTube, to access visualization of global precipitation datasets at the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC). With YouTube, users can access and visualize a large volume of satellite data without necessity to learn new software or download data. The dataset in this activity is the 3-hourly TRMM (Tropical Rainfall Measuring Mission) Multi-satellite Precipitation Analysis (TMPA). The video consists of over 50,000 data files collected since 1998 onwards, covering a zone between 50°N-S. The YouTube video will last 36 minutes for the entire dataset record (over 19 years). Since the time stamp is on each frame of the video, users can begin at any time by dragging the time progress bar. This precipitation animation will allow viewing precipitation events and processes (e.g., hurricanes, fronts, atmospheric rivers, etc.) on a global scale. The next plan is to develop a similar animation for the GPM (Global Precipitation Measurement) Integrated Multi-satellitE Retrievals for GPM (IMERG). The IMERG provides precipitation on a near-global (60°N-S) coverage at half-hourly time interval, showing more details on precipitation processes and development, compared to the 3

NOAA budget would boost satellite funding but cut some key areas

Science.gov (United States)

Showstack, Randy

2012-03-01

The White House's proposed fiscal year (FY) 2013 budget for the National Oceanic and Atmospheric Administration (NOAA), announced on 13 February, looks favorable at first glance. The administration's request calls for $5.1 billion, an increase of $153 million (3.1%) above the FY 2012 estimated budget. However, the increase for NOAA satellites is $163 million, which means that other areas within the agency would be slated for decreased funding, including programs within the National Ocean Service (NOS), National Marine Fisheries Service (NMFS), National Weather Service (NWS), and some NOAA education programs. The proposed overall budget for the agency “reflects the overarching importance of weather satellites to public safety, to national security, and to the economy,” NOAA director Jane Lubchenco said at a 16 February briefing, noting that difficult choices were made regarding the budget. “Due to significant resources required for our weather satellites and the economic conditions in the country, other parts of our budget have been reduced, in some cases quite significantly,” she said. She added that the imperative to fund both the Joint Polar Satellite System (JPSS) and geostationary satellites in FY 2013 “imposes serious constraints on the rest of NOAA's budget.”

Analysis of the partially filled viscous ring damper. [application as nutation damper for spinning satellite

Science.gov (United States)

Alfriend, K. T.

1973-01-01

A ring partially filled with a viscous fluid has been analyzed as a nutation damper for a spinning satellite. The fluid has been modelled as a rigid slug of finite length moving in a tube and resisted by a linear viscous force. It is shown that there are two distinct modes of motion, called the spin synchronous mode and the nutation synchronous mode. Time constants for each mode are obtained for both the symmetric and asymmetric satellite. The effects of a stop in the tube and an offset of the ring from the spin axis are also investigated. An analysis of test results is also given including a determination of the effect of gravity on the time constants in the two modes.

Instantaneous Shoreline Extraction Utilizing Integrated Spectrum and Shadow Analysis From LiDAR Data and High-resolution Satellite Imagery

Science.gov (United States)

Lee, I.-Chieh

manually connected, for its length was less than 3% of the total shoreline length in our dataset. Secondly, the parameters for satellite image classification needed to be manually determined. The need for manpower was significantly less compared to the ground surveying or aerial photogrammetry. The first phase of shoreline extraction was to utilize Normalized Difference Vegetation Index (NDVI), Mean-Shift segmentation on the coordinate (X, Y, Z), and attributes (multispectral bands from satellite images) of the LiDAR points to classify each LiDAR point into land or water surface. Boundary of the land points were then traced to create the shoreline. The second phase of shoreline extraction solely from satellite images utilized spectrum, NDVI, and shadow analysis to classify the satellite images into classes. These classes were then refined by mean-shift segmentation on the panchromatic band. By tracing the boundary of the water surface, the shoreline can be created. Since these two shorelines may represent different shoreline instances in time, evaluating the changes of shoreline was the first to be done. Then an independent scenario analysis and a procedure are performed for the shoreline of each of the three conditions: in the process of erosion, in the process of accession, and remaining the same. With these three conditions, we could analysis the actual terrain type and correct the classification errors to obtain a more accurate shoreline. Meanwhile, methods of evaluating the quality of shorelines had also been discussed. The experiment showed that there were three indicators could best represent the quality of the shoreline. These indicators were: (1) shoreline accuracy, (2) land area difference between extracted shoreline and ground truth shoreline, and (3) bias factor from shoreline quality metrics.

Orbit Determination of the SELENE Satellites Using Multi-Satellite Data Types and Evaluation of SELENE Gravity Field Models

Science.gov (United States)

Goossens, S.; Matsumoto, K.; Noda, H.; Araki, H.; Rowlands, D. D.; Lemoine, F. G.

2011-01-01

The SELENE mission, consisting of three separate satellites that use different terrestrial-based tracking systems, presents a unique opportunity to evaluate the contribution of these tracking systems to orbit determination precision. The tracking data consist of four-way Doppler between the main orbiter and one of the two sub-satellites while the former is over the far side, and of same-beam differential VLBI tracking between the two sub-satellites. Laser altimeter data are also used for orbit determination. The contribution to orbit precision of these different data types is investigated through orbit overlap analysis. It is shown that using four-way and VLBI data improves orbit consistency for all satellites involved by reducing peak values in orbit overlap differences that exist when only standard two-way Doppler and range data are used. Including laser altimeter data improves the orbit precision of the SELENE main satellite further, resulting in very smooth total orbit errors at an average level of 18m. The multi-satellite data have also resulted in improved lunar gravity field models, which are assessed through orbit overlap analysis using Lunar Prospector tracking data. Improvements over a pre-SELENE model are shown to be mostly in the along-track and cross-track directions. Orbit overlap differences are at a level between 13 and 21 m with the SELENE models, depending on whether l-day data overlaps or I-day predictions are used.

TELE-X and its role in a future operational Nordic satellite system

Science.gov (United States)

Anderson, Lars

In the middle of 1987 it is planned to launch TELE-X, the first Nordic telecommunications satellite. The Swedish-Norwegian company NOTELSAT (Nordic Telecommunications Satellite Corporation) will be responsible for the operation of the TELE-X system. Via the experimental TELE-X satellite the Nordic countries will get access to direct broadcasting of two TV-programs and at least four digital sound programs in stereo by use of two transponders in the 12.2 to 12.5 GHz band. The programs are planned to be composed of nationally produced programs in Norway. Sweden and Finland. By means of distributing these programs via satellite they will reach up to 4 times as many viewers and listernes as presently in the terrestrial national systems. The basic motivations for exchanging programs are to strengthen the cultural ties between the Nordic countries and to give the individuals more freedom in the choice of programs. Another goal is to give the public a better sound and picture quality than can be achieved today. These quality improvements shall be met by using small receiver parabolas of less than 1 m in diameter. Contributing to the improved quality is the choice of the C-MAC (Multiplexed Analoque Components) modulation system. TELE-X is a multipurpose satellite which besides the two TV-transponders will have two transponders for data/video communication in the frequency band 12.5 to 12.75 GHz. The choice of system for data and video is based on the philosophy of thin-route traffic between small and low cost earth stations (1.8 to 2.5 m) placed directly at the subscribers premises. The system includes an advanced Data/Video Control Station which automatically connects the traffic stations with standarized transmission speeds up to 2 Mbps. The system which is based on the SCPC/DAMA method can be expanded up to 5000 traffic stations. Numerous data/video applications will be investigated in the initial experimental phase of the project which also will be used for market

Photonically wired spacecraft panels: an economic analysis and demonstrator for telecommunication satellites

Science.gov (United States)

Putzer, Philipp; Hurni, Andreas; Ziegler, Bent; Panopoulou, Aikaterini; Lemke, Norbert; Costa, Ivo; Pereira, Celeste

2017-09-01

In this paper we present the design of smart satellite panels with integrated optical fibers for sensing and data communication. The project starts with a detailed analysis of the system needs and ends with a demonstrator breadboard showing the full performance during and after environmental tests such as vibrations and temperature. Future science missions will need higher bandwidth in the Gbit/s range for intra-satellite communications, so the step from electrical transmission media towards fiber-optical media is the logical next step to cope with future requirements. In addition, the fibers can be used to monitor temperatures directly underneath satellite payloads which will reduce the integration effort in a later phase. For temperature monitoring so called fiber Bragg gratings (FBGs) are written in special radiation tolerant fibers, which reflection wavelength allows a direct link to temperature at the grating position. A read-out system for FBGs to use within satellite applications is currently under development at OHB. For this study, first the environmental requirements for the panels are derived and in a second stage the functional requirements are defined. To define the functional requirements a telecommunication satellite platform, in the case here the Small-GEO series from OHB, has been taken as baseline. Based on the configuration of temperature sensors, communication lines and electrical signaling a possible replacement by fiber-optical technology was defined and traded w.r.t. its economic benefit. It has been pointed out that the replacement of temperature sensors will reduce harness mass, but the great benefit is seen here in the reduction of assembly effort. Once the satellite panel is manufactured, the temperature sensors are already implemented at certain positions. Another point for mass savings which has pointed out is the replacement of the high-voltage or high- current high power commands (HPC) by fiber optics. Replacing some of the several

Local wavelet correlation: applicationto timing analysis of multi-satellite CLUSTER data

Directory of Open Access Journals (Sweden)

J. Soucek

2004-12-01

Full Text Available Multi-spacecraft space observations, such as those of CLUSTER, can be used to infer information about local plasma structures by exploiting the timing differences between subsequent encounters of these structures by individual satellites. We introduce a novel wavelet-based technique, the Local Wavelet Correlation (LWC, which allows one to match the corresponding signatures of large-scale structures in the data from multiple spacecraft and determine the relative time shifts between the crossings. The LWC is especially suitable for analysis of strongly non-stationary time series, where it enables one to estimate the time lags in a more robust and systematic way than ordinary cross-correlation techniques. The technique, together with its properties and some examples of its application to timing analysis of bow shock and magnetopause crossing observed by CLUSTER, are presented. We also compare the performance and reliability of the technique with classical discontinuity analysis methods. Key words. Radio science (signal processing – Space plasma physics (discontinuities; instruments and techniques

Copyright Question: Using Audiovisual Works in a Satellite-Delivered Program.

Science.gov (United States)

Switzer, Jamie S.; Switzer, Ralph V., Jr.

1994-01-01

Examines the question of copyright violation of audiovisual materials when used in a Master's of Business Administration (MBA) degree offered via satellite transmission through Colorado State University. Topics discussed include fair use; definitions of literary works, performance, and transmission; and the need to revise the 1976 Copyright Act to…

Problem of spiral galaxies and satellite radio sources

International Nuclear Information System (INIS)

Arp, H.; Carpenter, R.; Gulkis, S.; Klein, M.

1976-01-01

A detailed comparison is made between the results of this program and the results of previous investigators. In particular, attention is called to the potentially important implications of an investigation by Tovmasyan, who searched a large number of spirals and found evidence that a small percentage of them apparently have radio satellites located up to 20' from the central galaxy. 15 sources were measured selected from Tovmasyan's list of 43 satellite sources. Results confirm his positions and relative flux densities for each of the sources

Arctic sea-level reconstruction analysis using recent satellite altimetry

DEFF Research Database (Denmark)

Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

2014-01-01

We present a sea-level reconstruction for the Arctic Ocean using recent satellite altimetry data. The model, forced by historical tide gauge data, is based on empirical orthogonal functions (EOFs) from a calibration period; for this purpose, newly retracked satellite altimetry from ERS-1 and -2...... and Envisat has been used. Despite the limited coverage of these datasets, we have made a reconstruction up to 82 degrees north for the period 1950–2010. We place particular emphasis on determining appropriate preprocessing for the tide gauge data, and on validation of the model, including the ability...

Analysis on BDS Satellite Internal Multipath and Its Impact on Wide-lane FCB Estimation

Directory of Open Access Journals (Sweden)

RUAN Rengui

2017-08-01

Full Text Available To the issue of the satellite internal multipath (SIMP of BeiDou satellites, it proposed and emphasized that the SIMP model should be established as a function of the nadir angle with respect to the observed satellite rather than the elevation of the measurement, so that it can be used for receivers at various altitude. BDS data from global distributed stations operated by the International Monitoring and Assessment System (iGMAS and the Multi-GNSS Experiment (MGEX of the International GNSS Service (IGS are collected and a new SIMP model as a piece-wise linear function of the nadir angle is released for the IGSO-and MEO-satellite groups and for B1, B2 and B3 frequency band individually. The SIMP of GEO,IGSO and MEO satellites is further analyzed with B1/B2 dual-frequency data onboard the FengYun-3 C(FY3C satellite at an altitude of~830 km, and it showed that, for nadir angles smaller than 7°, the SIMP values for GEO is quite close to the IGSO's, especially for B2, which may suggest that the SIMP model for IGSO satellites possibly also works for GEO satellites. It also demonstrated that, when the nadir angle is smaller than 12°for the MEO and 7°for the IGSO, the estimated SIMP model with data from FY3C is considerable consistent with that estimated with data collected at ground stations. Experiments are carried out to investigate the impacts of the SIMP on wide-lane fractional cycle bias (FCB estimation for BDS satellites. The result indicates that, with the correction of the estimated SIMP, the repeatability of the FCB series is significantly improved by more than 60% for all satellites. Specifically, for the MEO and IGSO satellites, the repeatability is smaller than 0.05 cycle; the repeatability of 0.023 and 0.068 cycles achieved for GEO satellites C01 and C02 respectively with the estimated SIMP model for IGSO satellites.

Satellite-based Tropical Cyclone Monitoring Capabilities

Science.gov (United States)

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

2012-12-01

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.

Satellite tracking and stable isotope analysis link wintering and feeding grounds of North Atlantic baleen whales

NARCIS (Netherlands)

e Silva, Monica Almeida; Prieto, Rui; Gauffier, Pauline; Palsboll, Per; Bérubé, Martine; Colaco, Ana

2017-01-01

Knowledge of the distribution of baleen whales throughout their annual cycle is critical for understanding their ecology, life history and behavior, and for their effective conservation. We combined analysis of stable isotopes (δ15N and δ13C) and satellite tracking data of blue (Balaenoptera

Advanced satellite servicing facility studies

Science.gov (United States)

Qualls, Garry D.; Ferebee, Melvin J., Jr.

1988-01-01

A NASA-sponsored systems analysis designed to identify and recommend advanced subsystems and technologies specifically for a manned Sun-synchronous platform for satellite management is discussed. An overview of system design, manned and unmanned servicing facilities, and representative mission scenarios are given. Mission areas discussed include facility based satellite assembly, checkout, deployment, refueling, repair, and systems upgrade. The ferrying of materials and consumables to and from manufacturing platforms, deorbit, removal, repositioning, or salvage of satellites and debris, and crew rescue of any other manned vehicles are also examined. Impacted subsytems discussed include guidance navigation and control, propulsion, data management, power, thermal control, structures, life support, and radiation management. In addition, technology issues which would have significant impacts on the system design are discussed.

CDRD and PNPR satellite passive microwave precipitation retrieval algorithms: EuroTRMM/EURAINSAT origins and H-SAF operations

Science.gov (United States)

Mugnai, A.; Smith, E. A.; Tripoli, G. J.; Bizzarri, B.; Casella, D.; Dietrich, S.; Di Paola, F.; Panegrossi, G.; Sanò, P.

2013-04-01

Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF) is a EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites) program, designed to deliver satellite products of hydrological interest (precipitation, soil moisture and snow parameters) over the European and Mediterranean region to research and operations users worldwide. Six satellite precipitation algorithms and concomitant precipitation products are the responsibility of various agencies in Italy. Two of these algorithms have been designed for maximum accuracy by restricting their inputs to measurements from conical and cross-track scanning passive microwave (PMW) radiometers mounted on various low Earth orbiting satellites. They have been developed at the Italian National Research Council/Institute of Atmospheric Sciences and Climate in Rome (CNR/ISAC-Rome), and are providing operational retrievals of surface rain rate and its phase properties. Each of these algorithms is physically based, however, the first of these, referred to as the Cloud Dynamics and Radiation Database (CDRD) algorithm, uses a Bayesian-based solution solver, while the second, referred to as the PMW Neural-net Precipitation Retrieval (PNPR) algorithm, uses a neural network-based solution solver. Herein we first provide an overview of the two initial EU research and applications programs that motivated their initial development, EuroTRMM and EURAINSAT (European Satellite Rainfall Analysis and Monitoring at the Geostationary Scale), and the current H-SAF program that provides the framework for their operational use and continued development. We stress the relevance of the CDRD and PNPR algorithms and their precipitation products in helping secure the goals of H-SAF's scientific and operations agenda, the former helpful as a secondary calibration reference to other algorithms in H-SAF's complete mix of algorithms. Descriptions of the algorithms' designs are provided

CDRD and PNPR satellite passive microwave precipitation retrieval algorithms: EuroTRMM/EURAINSAT origins and H-SAF operations

Directory of Open Access Journals (Sweden)

A. Mugnai

2013-04-01

Full Text Available Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF is a EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites program, designed to deliver satellite products of hydrological interest (precipitation, soil moisture and snow parameters over the European and Mediterranean region to research and operations users worldwide. Six satellite precipitation algorithms and concomitant precipitation products are the responsibility of various agencies in Italy. Two of these algorithms have been designed for maximum accuracy by restricting their inputs to measurements from conical and cross-track scanning passive microwave (PMW radiometers mounted on various low Earth orbiting satellites. They have been developed at the Italian National Research Council/Institute of Atmospheric Sciences and Climate in Rome (CNR/ISAC-Rome, and are providing operational retrievals of surface rain rate and its phase properties. Each of these algorithms is physically based, however, the first of these, referred to as the Cloud Dynamics and Radiation Database (CDRD algorithm, uses a Bayesian-based solution solver, while the second, referred to as the PMW Neural-net Precipitation Retrieval (PNPR algorithm, uses a neural network-based solution solver. Herein we first provide an overview of the two initial EU research and applications programs that motivated their initial development, EuroTRMM and EURAINSAT (European Satellite Rainfall Analysis and Monitoring at the Geostationary Scale, and the current H-SAF program that provides the framework for their operational use and continued development. We stress the relevance of the CDRD and PNPR algorithms and their precipitation products in helping secure the goals of H-SAF's scientific and operations agenda, the former helpful as a secondary calibration reference to other algorithms in H-SAF's complete mix of algorithms. Descriptions of the algorithms' designs are

Simobiz-Simulation Tool to Study the Impact of Small Satellites in Mobile Market

Science.gov (United States)

Burlacu, M.-M.; Kohlenberg, J.; Prathaban, M.

2008-08-01

Interest in small satellites is growing fast world- wide. Businesses, governments, universities and other organizations around the world are starting their own small satellite programs. The surveys conducted by the space agencies and universities shows a promising increase in the use of small satellites for commercial applications. More number of operators offers or plans to offer mobile phone services by satellite. With the help of cost effective small satellite, mobile operators can be able to provide the services cheaper. Hence, it is always interesting to study the effect of low cost small satellite over the mobile market. In this article, we present SmartSim (Small Satellites Mobile Market Simulator) - the new module of Simobiz business simulation game, in which we have implemented two operators, a normal satellite operator and a nanosatellite operator, with specific terminals and services. Our main focus in this work is to understand the future market of small satellite in mobile telecommunication network.

Static Analysis of Mobile Programs

Science.gov (United States)

2017-02-01

and not allowed, to do. The second issue was that a fully static analysis was never a realistic possibility, because Java , the programming langauge...scale to large programs it had to handle essentially all of the features of Java and could also be used as a general-purpose analysis engine. The...static analysis of imperative languages. • A framework for adding specifications about the behavior of methods, including methods that were

Skeletal Muscle Satellite Cells Are Committed to Myogenesis and Do Not Spontaneously Adopt Nonmyogenic Fates

Science.gov (United States)

Starkey, Jessica D.; Yamamoto, Masakazu; Yamamoto, Shoko; Goldhamer, David J.

2011-01-01

The developmental potential of skeletal muscle stem cells (satellite cells) remains controversial. The authors investigated satellite cell developmental potential in single fiber and clonal cultures derived from MyoDiCre/+;R26REYFP/+ muscle, in which essentially all satellite cells are permanently labeled. Approximately 60% of the clones derived from cells that co-purified with muscle fibers spontaneously underwent adipogenic differentiation. These adipocytes stained with Oil-Red-O and expressed the terminal differentiation markers, adipsin and fatty acid binding protein 4, but did not express EYFP and were therefore not of satellite cell origin. Satellite cells mutant for either MyoD or Myf-5 also maintained myogenic programming in culture and did not adopt an adipogenic fate. Incorporation of additional wash steps prior to muscle fiber plating virtually eliminated the non-myogenic cells but did not reduce the number of adherent Pax7+ satellite cells. More than half of the adipocytes observed in cultures from Tie2-Cre mice were recombined, further demonstrating a non-satellite cell origin. Under adipogenesis-inducing conditions, satellite cells accumulated cytoplasmic lipid but maintained myogenic protein expression and did not fully execute the adipogenic differentiation program, distinguishing them from adipocytes observed in muscle fiber cultures. The authors conclude that skeletal muscle satellite cells are committed to myogenesis and do not spontaneously adopt an adipogenic fate. PMID:21339173

Establishing and maintaining a satellite campus connected by synchronous video conferencing.

Science.gov (United States)

Fox, Brent I; McDonough, Sharon L; McConatha, Barry J; Marlowe, Karen F

2011-06-10

Pharmacy education has experienced substantial growth in the number of new schools and existing schools establishing satellite campuses. Several models have previously been used to connect primary and satellite campuses. We describe the Auburn University Harrison School of Pharmacy's (AUHSOP's) experiences using synchronous video conferencing between the Auburn University campus in Auburn and a satellite campus in Mobile, Alabama. We focus on the technology considerations related to planning, construction, implementation, and continued use of the various resources that support our program. Students' perceptions of their experiences related to technology also are described.

Analysis of GPS Satellite Allocation for the United States Nuclear Detonation Detection System (USNDS)

National Research Council Canada - National Science Library

Bell, Aaron

2002-01-01

...) satellites to detect atmospheric nuclear detonations. Though there are currently over 24 operational GPS satellites, USNDS ground based antennas are only capable of actively monitoring 24 satellites at a time...

Modeling and simulation of satellite subsystems for end-to-end spacecraft modeling

Science.gov (United States)

Schum, William K.; Doolittle, Christina M.; Boyarko, George A.

2006-05-01

During the past ten years, the Air Force Research Laboratory (AFRL) has been simultaneously developing high-fidelity spacecraft payload models as well as a robust distributed simulation environment for modeling spacecraft subsystems. Much of this research has occurred in the Distributed Architecture Simulation Laboratory (DASL). AFRL developers working in the DASL have effectively combined satellite power, attitude pointing, and communication link analysis subsystem models with robust satellite sensor models to create a first-order end-to-end satellite simulation capability. The merging of these two simulation areas has advanced the field of spacecraft simulation, design, and analysis, and enabled more in-depth mission and satellite utility analyses. A core capability of the DASL is the support of a variety of modeling and analysis efforts, ranging from physics and engineering-level modeling to mission and campaign-level analysis. The flexibility and agility of this simulation architecture will be used to support space mission analysis, military utility analysis, and various integrated exercises with other military and space organizations via direct integration, or through DOD standards such as Distributed Interaction Simulation. This paper discusses the results and lessons learned in modeling satellite communication link analysis, power, and attitude control subsystems for an end-to-end satellite simulation. It also discusses how these spacecraft subsystem simulations feed into and support military utility and space mission analyses.

Satellite Based Education and Training in Remote Sensing and Geo-Information AN E-Learning Approach to Meet the Growing Demands in India

Science.gov (United States)

Raju, P. L. N.; Gupta, P. K.

2012-07-01

One of the prime activities of Indian Space Research Organisation's (ISRO) Space Program is providing satellite communication services, viz., television broadcasting, mobile communication, cyclone disaster warning and rescue operations etc. so as to improve their economic conditions, disseminate technical / scientific knowledge to improve the agriculture production and education for rural people of India. ISRO, along with National Aeronautical and Space Administration (NASA) conducted experimental satellite communication project i.e. Satellite Instructional Television Experiment (SITE) using NASA's Advanced Telecommunication Satellite (i.e. ATS 6) with an objective to educate poor people of India via satellite broadcasting in 1975 and 1976, covering more than 2600 villages in six states of India and territories. Over the years India built communication satellites indigenously to meet the communication requirements of India. This has further lead to launch of an exclusive satellite from ISRO for educational purposes i.e. EDUSAT in 2004 through which rich audio-video content is transmitted / received, recreating virtual classes through interactivity. Indian Institute of Remote Sensing (IIRS) established in 1966, a premier institute in south East Asia in disseminating Remote Sensing (RS) and Geographical Information System (GIS), mainly focusing on contact based programs. But expanded the scope with satellite based Distance Learning Programs for Universities, utilizing the dedicated communication satellite i.e. EDUSAT in 2007. IIRS conducted successfully eight Distance Learning Programs in the last five years and training more than 6000 students mainly at postgraduate level from more than 60 universities /Institutions spread across India. IIRS obtained feedback and improved the programs on the continuous basis. Expanded the scope of IIRS outreach program to train user departments tailor made in any of the applications of Remote Sensing and Geoinformation, capacity

SATELLITE BASED EDUCATION AND TRAINING IN REMOTE SENSING AND GEO-INFORMATION: AN E-LEARNING APPROACH TO MEET THE GROWING DEMANDS IN INDIA

Directory of Open Access Journals (Sweden)

P. L. N. Raju

2012-07-01

Full Text Available One of the prime activities of Indian Space Research Organisation's (ISRO Space Program is providing satellite communication services, viz., television broadcasting, mobile communication, cyclone disaster warning and rescue operations etc. so as to improve their economic conditions, disseminate technical / scientific knowledge to improve the agriculture production and education for rural people of India. ISRO, along with National Aeronautical and Space Administration (NASA conducted experimental satellite communication project i.e. Satellite Instructional Television Experiment (SITE using NASA’s Advanced Telecommunication Satellite (i.e. ATS 6 with an objective to educate poor people of India via satellite broadcasting in 1975 and 1976, covering more than 2600 villages in six states of India and territories. Over the years India built communication satellites indigenously to meet the communication requirements of India. This has further lead to launch of an exclusive satellite from ISRO for educational purposes i.e. EDUSAT in 2004 through which rich audio-video content is transmitted / received, recreating virtual classes through interactivity. Indian Institute of Remote Sensing (IIRS established in 1966, a premier institute in south East Asia in disseminating Remote Sensing (RS and Geographical Information System (GIS, mainly focusing on contact based programs. But expanded the scope with satellite based Distance Learning Programs for Universities, utilizing the dedicated communication satellite i.e. EDUSAT in 2007. IIRS conducted successfully eight Distance Learning Programs in the last five years and training more than 6000 students mainly at postgraduate level from more than 60 universities /Institutions spread across India. IIRS obtained feedback and improved the programs on the continuous basis. Expanded the scope of IIRS outreach program to train user departments tailor made in any of the applications of Remote Sensing and

Impact analysis of satellite rainfall products on flow simulations in the Magdalena River Basin, Colombia

Directory of Open Access Journals (Sweden)

Amr Elgamal

2017-02-01

Full Text Available The Magdalena River is the most important river in Colombia in terms of economic activities and is home to about 77% of the country’s population. The river faces water resources allocation challenges, which require reliable hydrological assessments. However, hydrological analysis and model simulations are hampered by insufficient and uncertain knowledge of the actual rainfall fields. In this research the reliability of groundbased measurements, different satellite products of rainfall and their combinations are tested for their impact on the discharge simulations of the Magdalena River. Two different satellite rainfall products from the Tropical Rainfall Measuring Mission (TRMM, have been compared and merged with the ground-based measurements and their impact on the Magdalena river flows quantified using the Representative Elementary Watershed (REW distributed hydrological model.

LMSS SERVICES FINANCIAL REPORT PROGRAM

Science.gov (United States)

Chamberlain, R. G.

1994-01-01

The objective of this Services Finance Report program is to provide a means for comparing alternative designs of LMSS systems or other services systems. This program is actually a Multiplan worksheet. The labels used in the worksheet were chosen for a satellite-based cellular communication service (LMSS - Land Mobile Satellite System) but the analysis is not restricted to such cases. A comprehensive financial model is used to calculate a 'figure of merit' which can be used to compare effects of equipment and operating costs, pricing strategy, and customer demand for different systems. The program also calculates the price that a company would have to charge customers to meet all its expenses and make a specified profit. A price estimate can be obtained for almost any service which is heavily dependent on capital investment and which has operating costs that depend on the amount of service sold. The economic analysis has two main components: supplier finances and customer finances. Supplier finances include amortization, interest, insurance, taxes, and operating and maintenance expenses. Customer finances include usage rate, subscription fees, equipment costs, and estimated traffic. Prices can defined as real or nominal to account for effects of escalation and inflation, and the profits can be regulated or unrestricted This program is written for interactive execution with Multiplan (version 1.2) and has been implemented on an IBM PC series computer operating under DOS (version 2.11). The LMSS worksheet has a space requirement of approximately 38K of 8 bit bytes. This worksheet was developed in 1984.

A high-fidelity N-body ephemeris generator for satellites in Earth orbit

Science.gov (United States)

Simmons, David R.

1991-10-01

A program is currently used for mission planning called the Analytic Satellite Ephemeris Program (ASEP), which produces projected data for orbits that remain fairly close to Earth. Lunar and solar perturbations are taken into account in another program called GRAVE. This project is a revision of GRAVE which incorporates more flexible means of input for initial data, provides additional kinds of output information, and makes use of structured programming techniques to make the program more understandable and reliable. The computer program ORBIT was tested against tracking data for the first 313 days of operation of the CRRES satellite. A sample graph is given comparing the semi-major axis calculated by the program with the values supplied by NORAD. When calculated for points at which CRRES passes through the ascending node, the argument of perigee, the right ascension of the ascending node, and the mean anomaly all stay within about a degree of the corresponding values from NORAD; the inclination of the orbital plane is much closer. The program value of the eccentricity is in error by no more than 0.0002.

Earth Observatory Satellite system definition study. Report 3: Design cost trade-off studies and recommendations

Science.gov (United States)

1974-01-01

An analysis of the design and cost tradeoff aspects of the Earth Observatory Satellite (EOS) development is presented. The design/cost factors that affect a series of mission/system level concepts are discussed. The subjects considered are as follows: (1) spacecraft subsystem cost tradeoffs, (2) ground system cost tradeoffs, and (3) program cost summary. Tables of data are provided to summarize the results of the analyses. Illustrations of the various spacecraft configurations are included.

Comprehensive Comparisons of Satellite Data, Signals, and Measurements between the BeiDou Navigation Satellite System and the Global Positioning System †

Science.gov (United States)

Jan, Shau-Shiun; Tao, An-Lin

2016-01-01

The Chinese BeiDou navigation satellite system (BDS) aims to provide global positioning service by 2020. The combined use of BDS and Global Positioning System (GPS) is proposed to provide navigation service with more stringent requirements. Actual satellite data, signals and measurements were collected for more than one month to analyze the positioning service qualities from both BDS and GPS. In addition to the conversions of coordinate and timing system, five data quality analysis (DQA) methods, three signal quality analysis (SQA) methods, and four measurement quality analysis (MQA) methods are proposed in this paper to improve the integrated positioning performance of BDS and GPS. As shown in the experiment results, issues related to BDS and GPS are resolved by the above proposed quality analysis methods. Thus, the anomalies in satellite data, signals and measurements can be detected by following the suggested resolutions to enhance the positioning performance of the combined use of BDS and GPS in the Asia Pacific region. PMID:27187403

Design and Fabrication of DebriSat - A Representative LEO Satellite for Improvements to Standard Satellite Breakup Models

Science.gov (United States)

Clark, S.; Dietrich, A.; Fitz-Coy, N.; Weremeyer, M.; Liou, J.-C.

2012-01-01

This paper discusses the design and fabrication of DebriSat, a 50 kg satellite developed to be representative of a modern low Earth orbit satellite in terms of its components, materials used, and fabrication procedures. DebriSat will be the target of a future hypervelocity impact experiment to determine the physical characteristics of debris generated after an on-orbit collision of a modern LEO satellite. The major ground-based satellite impact experiment used by DoD and NASA in their development of satellite breakup models was SOCIT, conducted in 1992. The target used for that experiment was a Navy transit satellite (40 cm, 35 kg) fabricated in the 1960's. Modern satellites are very different in materials and construction techniques than those built 40 years ago. Therefore, there is a need to conduct a similar experiment using a modern target satellite to improve the fidelity of the satellite breakup models. To ensure that DebriSat is truly representative of typical LEO missions, a comprehensive study of historical LEO satellite designs and missions within the past 15 years for satellites ranging from 1 kg to 5000 kg was conducted. This study identified modern trends in hardware, material, and construction practices utilized in recent LEO missions. Although DebriSat is an engineering model, specific attention is placed on the quality, type, and quantity of the materials used in its fabrication to ensure the integrity of the outcome. With the exception of software, all other aspects of the satellite s design, fabrication, and assembly integration and testing will be as rigorous as that of an actual flight vehicle. For example, to simulate survivability of launch loads, DebriSat will be subjected to a vibration test. As well, the satellite will undergo thermal vacuum tests to verify that the components and overall systems meet typical environmental standards. Proper assembly and integration techniques will involve comprehensive joint analysis, including the precise

Satellite Control Laboratory

DEFF Research Database (Denmark)

Wisniewski, Rafal; Bak, Thomas

2001-01-01

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......-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...... 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....

Meteorological Satellites (METSAT) and Earth Observing System (EOS) Advanced Microwave Sounding Unit-A (AMSU-A) Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL)

Science.gov (United States)

1996-01-01

This Failure Modes and Effects Analysis (FMEA) is for the Advanced Microwave Sounding Unit-A (AMSU-A) instruments that are being designed and manufactured for the Meteorological Satellites Project (METSAT) and the Earth Observing System (EOS) integrated programs. The FMEA analyzes the design of the METSAT and EOS instruments as they currently exist. This FMEA is intended to identify METSAT and EOS failure modes and their effect on spacecraft-instrument and instrument-component interfaces. The prime objective of this FMEA is to identify potential catastrophic and critical failures so that susceptibility to the failures and their effects can be eliminated from the METSAT/EOS instruments.

Analysis of raw AIS spectrum recordings from a LEO satellite

DEFF Research Database (Denmark)

Larsen, Jesper Abildgaard; Mortensen, Hans Peter

2014-01-01

The AAUSAT3 satellite is a 1U cubesat, which has been developed by students at Aalborg University, Denmark in collaboration with the Danish Maritime Authority. The satellite was launched in February 2013 on a mission to monitor ships from space using their AIS broadcast signals as an indication...... of position. The SDR receiver developed to listen for these AIS signals also allows for sampling and storing of the raw intermediate frequency spectrum, which has been used in order to map channel utilization over the areas of interest for the mission, which is mainly the arctic regions. The SDR based...... receiver used onboard the satellite is using a single chip front-end solution, which down converts the AIS signal located around 162 MHz into an intermediate frequency, with a up to 200 kHz bandwidth. This I/F signal is sampled with a 750 kSPS A/D converter and further processed by an Analog Devices DSP...

Scaling Analysis of Ocean Surface Turbulent Heterogeneities from Satellite Remote Sensing: Use of 2D Structure Functions.

Directory of Open Access Journals (Sweden)

P R Renosh

Full Text Available Satellite remote sensing observations allow the ocean surface to be sampled synoptically over large spatio-temporal scales. The images provided from visible and thermal infrared satellite observations are widely used in physical, biological, and ecological oceanography. The present work proposes a method to understand the multi-scaling properties of satellite products such as the Chlorophyll-a (Chl-a, and the Sea Surface Temperature (SST, rarely studied. The specific objectives of this study are to show how the small scale heterogeneities of satellite images can be characterised using tools borrowed from the fields of turbulence. For that purpose, we show how the structure function, which is classically used in the frame of scaling time series analysis, can be used also in 2D. The main advantage of this method is that it can be applied to process images which have missing data. Based on both simulated and real images, we demonstrate that coarse-graining (CG of a gradient modulus transform of the original image does not provide correct scaling exponents. We show, using a fractional Brownian simulation in 2D, that the structure function (SF can be used with randomly sampled couple of points, and verify that 1 million of couple of points provides enough statistics.

XML Graphs in Program Analysis

DEFF Research Database (Denmark)

Møller, Anders; Schwartzbach, Michael I.

2011-01-01

of XML graphs against different XML schema languages, and provide a software package that enables others to make use of these ideas. We also survey the use of XML graphs for program analysis with four very different languages: XACT (XML in Java), Java Servlets (Web application programming), XSugar......XML graphs have shown to be a simple and effective formalism for representing sets of XML documents in program analysis. It has evolved through a six year period with variants tailored for a range of applications. We present a unified definition, outline the key properties including validation...

A statistical inference approach for the retrieval of the atmospheric ozone profile from simulated satellite measurements of solar backscattered ultraviolet radiation

Science.gov (United States)

Bonavito, N. L.; Gordon, C. L.; Inguva, R.; Serafino, G. N.; Barnes, R. A.

1994-01-01

NASA's Mission to Planet Earth (MTPE) will address important interdisciplinary and environmental issues such as global warming, ozone depletion, deforestation, acid rain, and the like with its long term satellite observations of the Earth and with its comprehensive Data and Information System. Extensive sets of satellite observations supporting MTPE will be provided by the Earth Observing System (EOS), while more specific process related observations will be provided by smaller Earth Probes. MTPE will use data from ground and airborne scientific investigations to supplement and validate the global observations obtained from satellite imagery, while the EOS satellites will support interdisciplinary research and model development. This is important for understanding the processes that control the global environment and for improving the prediction of events. In this paper we illustrate the potential for powerful artificial intelligence (AI) techniques when used in the analysis of the formidable problems that exist in the NASA Earth Science programs and of those to be encountered in the future MTPE and EOS programs. These techniques, based on the logical and probabilistic reasoning aspects of plausible inference, strongly emphasize the synergetic relation between data and information. As such, they are ideally suited for the analysis of the massive data streams to be provided by both MTPE and EOS. To demonstrate this, we address both the satellite imagery and model enhancement issues for the problem of ozone profile retrieval through a method based on plausible scientific inferencing. Since in the retrieval problem, the atmospheric ozone profile that is consistent with a given set of measured radiances may not be unique, an optimum statistical method is used to estimate a 'best' profile solution from the radiances and from additional a priori information.

Analysis of Multipath Mitigation Techniques with Land Mobile Satellite Channel Model

Directory of Open Access Journals (Sweden)

M. Z. H. Bhuiyan J. Zhang

2012-12-01

is of utmost importance to analyze the performance of different multipath mitigation techniques in some realistic measurement-based channel models, for example, the Land Mobile Satellite (LMS channel model [1]-[4], developed at the German Aerospace Center (DLR. The DLR LMS channel model is widely used for simulating the positioning accuracy of mobile satellite navigation receivers in urban outdoor scenarios. The main objective of this paper is to present a comprehensive analysis of some of the most promising techniques with the DLR LMS channel model in varying multipath scenarios. Four multipath mitigation techniques are chosen herein for performance comparison, namely, the narrow Early-Minus-Late (nEML, the High Resolution Correlator, the C/N0-based two stage delay tracking technique, and the Reduced Search Space Maximum Likelihood (RSSML delay estimator. The first two techniques are the most popular and traditional ones used in nowadays GNSS receivers, whereas the later two techniques are comparatively new and are advanced techniques, recently proposed by the authors. In addition, the implementation of the RSSML is optimized here for a narrow-bandwidth receiver configuration in the sense that it now requires a significantly less number of correlators and memory than its original implementation. The simulation results show that the reduced-complexity RSSML achieves the best multipath mitigation performance in moderate-to-good carrier-to-noise density ratio with the DLR LMS channel model in varying multipath scenarios.

THE MASSIVE SATELLITE POPULATION OF MILKY-WAY-SIZED GALAXIES

International Nuclear Information System (INIS)

Rodríguez-Puebla, Aldo; Avila-Reese, Vladimir; Drory, Niv

2013-01-01

Several occupational distributions for satellite galaxies more massive than m * ≈ 4 × 10 7 M ☉ around Milky-Way (MW)-sized hosts are presented and used to predict the internal dynamics of these satellites as a function of m * . For the analysis, a large galaxy group mock catalog is constructed on the basis of (sub)halo-to-stellar mass relations fully constrained with currently available observations, namely the galaxy stellar mass function decomposed into centrals and satellites, and the two-point correlation functions at different masses. We find that 6.6% of MW-sized galaxies host two satellites in the mass range of the Small and Large Magellanic Clouds (SMC and LMC, respectively). The probabilities of the MW-sized galaxies having one satellite equal to or larger than the LMC, two satellites equal to or larger than the SMC, or three satellites equal to or larger than Sagittarius (Sgr) are ≈0.26, 0.14, and 0.14, respectively. The cumulative satellite mass function of the MW, N s (≥m * ) , down to the mass of the Fornax dwarf is within the 1σ distribution of all the MW-sized galaxies. We find that MW-sized hosts with three satellites more massive than Sgr (as the MW) are among the most common cases. However, the most and second most massive satellites in these systems are smaller than the LMC and SMC by roughly 0.7 and 0.8 dex, respectively. We conclude that the distribution N s (≥m * ) for MW-sized galaxies is quite broad, the particular case of the MW being of low frequency but not an outlier. The halo mass of MW-sized galaxies correlates only weakly with N s (≥m * ). Then, it is not possible to accurately determine the MW halo mass by means of its N s (≥m * ); from our catalog, we constrain a lower limit of 1.38 × 10 12 M ☉ at the 1σ level. Our analysis strongly suggests that the abundance of massive subhalos should agree with the abundance of massive satellites in all MW-sized hosts, i.e., there is not a missing (massive) satellite problem

A Conceptual Design for a Small Deployer Satellite

Science.gov (United States)

Zumbo, S.

2002-01-01

In the last few years, the space scientific and industrial communities have demonstrated a renewed interest for small missions based on new categories of space platforms: micro &nano satellites. The cost reduction w.r.t. larger satellite missions, the shorter time from concept to launch, the risk distribution and the possibility to use this kind of bus both for stand-alone projects and as complementary to larger programs, are key factors that make this new kind of technology suitable for a wide range of space related activities. In particular it is now possible to conceive new mission philosophy implying the realisation of micro satellite constellations, with S/C flying in close formation to form a network of distributed sensors either for near-real time telecommunication or Earth remote sensing and disaster monitoring systems or physics and astronomical researches for Earth-Sun dynamics and high energy radiation studies. At the same time micro satellite are becoming important test- beds for new technologies that will eventually be used on larger missions, with relevant spin-offs potentialities towards other industrial fields. The foreseen social and economical direct benefits, the reduced mission costs and the possibility even for a small skilled team to manage all the project, represent very attractive arguments for universities and research institutes to invest funds and human resources to get first order technical and theoretical skills in the field of micro satellite design, with important influences on the training programs of motivated students that are directly involved in all the project's phases. In consideration of these space market important new trends and of the academic benefits that could be guaranteed by undertaking a micro satellite mission project, basing on its long space activities heritage, University of Rome "La Sapienza" - Aerospace and Astronautics Department, with the support of the Italian Space Agency, Alenia Spazio and of important

Single versus mixture Weibull distributions for nonparametric satellite reliability

International Nuclear Information System (INIS)

Castet, Jean-Francois; Saleh, Joseph H.

2010-01-01

Long recognized as a critical design attribute for space systems, satellite reliability has not yet received the proper attention as limited on-orbit failure data and statistical analyses can be found in the technical literature. To fill this gap, we recently conducted a nonparametric analysis of satellite reliability for 1584 Earth-orbiting satellites launched between January 1990 and October 2008. In this paper, we provide an advanced parametric fit, based on mixture of Weibull distributions, and compare it with the single Weibull distribution model obtained with the Maximum Likelihood Estimation (MLE) method. We demonstrate that both parametric fits are good approximations of the nonparametric satellite reliability, but that the mixture Weibull distribution provides significant accuracy in capturing all the failure trends in the failure data, as evidenced by the analysis of the residuals and their quasi-normal dispersion.

Stress analysis program system for nuclear vessel: STANSAS

International Nuclear Information System (INIS)

Okamoto, Asao; Michikami, Shinsuke

1979-01-01

IHI has developed a computer system of stress analysis and evaluation for nuclear vessels: STANSAS (STress ANalysis System for Axi-symmetric Structure). The system consists of more than twenty independent programs divided into the following six parts. 1. Programs for opening design by code rule. 2. Calculation model generating programs. 3. Load defining programs. 4. Structural analysis programs. 5. Load data/calculation results plotting programs. 6. Stress evaluation programs. Each program is connected with its pre- or post-processor through three data-bases which enable automatic data transfer. The user can make his choice of structural analysis programs in accordance with the problem to be solved. The interface to STANSAS can be easily installed in generalized structural analysis programs such as NASTRAN and MARC. For almost all tables and figures in the stress report, STANSAS has the function to print or plot out. The complicated procedures of ''Design by Analysis'' for pressure vessels have been well standardized by STANSAS. The system will give a high degree of efficiency and confidence to the design work. (author)

Precipitation Analysis at Fine Time Scales using TRMM and Other Satellites: Realtime and Research Products and Applications

Science.gov (United States)

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

2004-01-01

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 (trmm.gsfc.nasa.gov) at 0.25 deg latitude-longitude resolution over the latitude range from 50 deg N-50 deg 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, 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.

Improving the Determination of Eastern Elongations of Planetary Satellites in the Astronomical Almanac

Science.gov (United States)

Rura, Christopher; Stollberg, Mark

2018-01-01

The Astronomical Almanac is an annual publication of the US Naval Observatory (USNO) and contains a wide variety of astronomical data used by astronomers worldwide as a general reference or for planning observations. Included in this almanac are the times of greatest eastern and northern elongations of the natural satellites of the planets, accurate to 0.1 hour UT. The production code currently used to determine elongation times generates X and Y coordinates for each satellite (16 total) in 5 second intervals. This consequentially caused very large data files, and resulted in the program devoted to determining the elongation times to be computationally intensive. To make this program more efficient, we wrote a Python program to fit a cubic spline to data generated with a 6-minute time step. This resulted in elongation times that were found to agree with those determined from the 5 second data currently used in a large number of cases and was tested for 16 satellites between 2017 and 2019. The accuracy of this program is being tested for the years past 2019 and, if no problems are found, the code will be considered for production of this section of The Astronomical Almanac.

THE THREE-DIMENSIONAL STRUCTURE OF THE M31 SATELLITE SYSTEM; STRONG EVIDENCE FOR AN INHOMOGENEOUS DISTRIBUTION OF SATELLITES

International Nuclear Information System (INIS)

Conn, A. R.; Parker, Q. A.; Zucker, D. B.; Lewis, G. F.; Ibata, R. A.; Martin, N. F.; McConnachie, A. W.; Valls-Gabaud, D.; Tanvir, N.; Irwin, M. J.; Ferguson, A. M. N.; Chapman, S. C.

2013-01-01

We undertake an investigation into the spatial structure of the M31 satellite system utilizing the distance distributions presented in a previous publication. These distances make use of the unique combination of depth and spatial coverage of the Pan-Andromeda Archaeological Survey to provide a large, homogeneous sample consisting of 27 of M31's satellites, as well as M31 itself. We find that the satellite distribution, when viewed as a whole, is no more planar than one would expect from a random distribution of equal size. A disk consisting of 15 of the satellites is however found to be highly significant, and strikingly thin, with an rms thickness of just 12.34 +0.75 -0.43 kpc. This disk is oriented approximately edge-on with respect to the Milky Way and almost perpendicular to the Milky Way disk. It is also roughly orthogonal to the disk-like structure regularly reported for the Milky Way satellite system and in close alignment with M31's Giant Stellar Stream. A similar analysis of the asymmetry of the M31 satellite distribution finds that it is also significantly larger than one would expect from a random distribution. In particular, it is remarkable that 20 of the 27 satellites most likely lie on the Milky Way side of the galaxy, with the asymmetry being most pronounced within the satellite subset forming the aforementioned disk. This lopsidedness is all the more intriguing in light of the apparent orthogonality observed between the satellite disk structures of the Milky Way and M31.

Analysis of a Proposal for an Education Satellite.

Science.gov (United States)

EDSAT Inst., Washington, DC.

Arguing that telecommunications is transforming almost every sector of American society except education, this study analyzed the governance, management, technical, and fiscal issues associated with the creation and maintenance of an education satellite telecommunications system that would make cost-effective, equitable access to quality education…

Coherent Uncertainty Analysis of Aerosol Measurements from Multiple Satellite Sensors

Science.gov (United States)

Petrenko, M.; Ichoku, C.

2013-01-01

Aerosol retrievals from multiple spaceborne sensors, including MODIS (on Terra and Aqua), MISR, OMI, POLDER, CALIOP, and SeaWiFS altogether, a total of 11 different aerosol products were comparatively analyzed using data collocated with ground-based aerosol observations from the Aerosol Robotic Network (AERONET) stations within the Multi-sensor Aerosol Products Sampling System (MAPSS, http://giovanni.gsfc.nasa.gov/mapss/ and http://giovanni.gsfc.nasa.gov/aerostat/). The analysis was performed by comparing quality-screened satellite aerosol optical depth or thickness (AOD or AOT) retrievals during 2006-2010 to available collocated AERONET measurements globally, regionally, and seasonally, and deriving a number of statistical measures of accuracy. We used a robust statistical approach to detect and remove possible outliers in the collocated data that can bias the results of the analysis. Overall, the proportion of outliers in each of the quality-screened AOD products was within 12%. Squared correlation coefficient (R2) values of the satellite AOD retrievals relative to AERONET exceeded 0.6, with R2 for most of the products exceeding 0.7 over land and 0.8 over ocean. Root mean square error (RMSE) values for most of the AOD products were within 0.15 over land and 0.09 over ocean. We have been able to generate global maps showing regions where the different products present advantages over the others, as well as the relative performance of each product over different landcover types. It was observed that while MODIS, MISR, and SeaWiFS provide accurate retrievals over most of the landcover types, multi-angle capabilities make MISR the only sensor to retrieve reliable AOD over barren and snow / ice surfaces. Likewise, active sensing enables CALIOP to retrieve aerosol properties over bright-surface shrublands more accurately than the other sensors, while POLDER, which is the only one of the sensors capable of measuring polarized aerosols, outperforms other sensors in

NOAA-L satellite is mated to Apogee Kick Motor at Vandenberg AFB

Science.gov (United States)

2000-01-01

Inside the B16-10 spacecraft processing hangar at Vandenberg Air Force Base, Calif., workers oversee the mating of the Apogee Kick Motor (below) to the National Oceanic and Atmospheric Administration (NOAA-L) satellite above. NOAA-L is part of the Polar-Orbiting Operational Environmental Satellite (POES) program that provides atmospheric measurements of temperature, humidity, ozone and cloud images, tracking weather patterns that affect the global weather and climate. The launch of the NOAA-L satellite is scheduled no earlier than Sept. 12 aboard a Lockheed Martin Titan II rocket. Advanced Communications Technology Satellite (ACTS): Four-Year System Performance

Science.gov (United States)

Acosta, Roberto J.; Bauer, Robert; Krawczyk, Richard J.; Reinhart, Richard C.; Zernic, Michael J.; Gargione, Frank

1999-01-01

The Advanced Communications Technology Satellite (ACTS) was conceived at the National Aeronautics and Space Administration (NASA) in the late 1970's as a follow-on program to ATS and CTS to continue NASA's long history of satellite communications projects. The ACTS project set the stage for the C-band satellites that started the industry, and later the ACTS project established the use of Ku-band for video distribution and direct-to-home broadcasting. ACTS, launched in September 1993 from the space shuttle, created a revolution in satellite system architecture by using digital communications techniques employing key technologies such as a fast hopping multibeam antenna, an on-board baseband processor, a wide-band microwave switch matrix, adaptive rain fade compensation, and the use of 900 MHz transponders operating at Ka-band frequencies. This paper describes the lessons learned in each of the key ACTS technology areas, as well as in the propagation investigations.

40 Years Young: Social Media for the World's Longest-Running Earth-Observation Satellite Program

Science.gov (United States)

Riebeek, H.; Rocchio, L. E.; Taylor, M.; Owen, T.; Allen, J. E.; Keck, A.

2012-12-01

With social media becoming a communication juggernaut it is essential to harness the medium's power to foster better science communication. On July 23, 2012, the Landsat Earth-observing satellite program celebrated the 40th anniversary of the first Landsat launch. To more effectively communicate the impact and importance of Landsat's four-decade long data record a carefully planned social media event was designed to supplement the day's traditional media communications. The social media event, dubbed the "Landsat Social," was modeled on and supported by the NASA Social methodology. The Landsat Social was the first such event for NASA Earth science not associated with a launch. For the Landsat Social, 23 social media-savvy participants were selected to attend a joint NASA/U.S. Geological Survey Landsat anniversary press event at the Newseum in Washington, D.C. The participants subsequently toured the NASA Goddard Space Flight Facility in Greenbelt, Maryland where they had the opportunity to learn about the latest Landsat satellite; visit the Landsat mission control; download and work with Landsat data; and meet Landsat scientists and engineers. All Landsat Social participants had Twitter accounts and used the #Landsat and #NASASocial hashtags to unify their commentary throughout the day. A few key Landsat messages were communicated to the Landsat Social participants at the event's onset. Propagation of this messaging was witnessed for the duration of the Landsat Social; and a spike in online Landsat interest followed. Here, we examine the Landsat 40th anniversary social event, explain impacts made, and report lessons learned.; Landsat Social attendees are busy tweeting, texting, and blogging as Project Scientist Dr. Jim Irons talks about the Landsat Data Continuity Mission in front of the Hyperwall at NASA Goddard Space Flight Center. Photo courtesy Bill Hrybyk.

Engineering a Responsive, Low Cost, Tactical Satellite, TacSat-1

OpenAIRE

Hurley, Michael; Duffey, Timothy; Huffine, Christopher; Weldy, Ken; Cleveland, Jeff; Hauser, Joe

2004-01-01

The Secretary of Defense’s Office of Force Transformation (OFT) is currently undertaking an initiative to develop a low-cost, responsive, operationally relevant space capability using small satellites. The Naval Research Laboratory (NRL) is tasked to be program manger for this initiative, which seeks to make space assets and capabilities available to operational users. TacSat-1 is the first in a series of small satellites that will result in rapid, tailored, and operationally relevant experim...

A methodology for calibration of hyperspectral and multispectral satellite data in coastal areas

Science.gov (United States)

Pennucci, Giuliana; Fargion, Giulietta; Alvarez, Alberto; Trees, Charles; Arnone, Robert

2012-06-01

The objective of this work is to determine the location(s) in any given oceanic area during different temporal periods where in situ sampling for Calibration/Validation (Cal/Val) provides the best capability to retrieve accurate radiometric and derived product data (lowest uncertainties). We present a method to merge satellite imagery with in situ measurements, to determine the best in situ sampling strategy suitable for satellite Cal/Val and to evaluate the present in situ locations through uncertainty indices. This analysis is required to determine if the present in situ sites are adequate for assessing uncertainty and where additional sites and ship programs should be located to improve Calibration/Validation (Cal/Val) procedures. Our methodology uses satellite acquisitions to build a covariance matrix encoding the spatial-temporal variability of the area of interest. The covariance matrix is used in a Bayesian framework to merge satellite and in situ data providing a product with lower uncertainty. The best in situ location for Cal/Val is then identified by using a design principle (A-optimum design) that looks for minimizing the estimated variance of the merged products. Satellite products investigated in this study include Ocean Color water leaving radiance, chlorophyll, and inherent and apparent optical properties (retrieved from MODIS and VIIRS). In situ measurements are obtained from systems operated on fixed deployment platforms (e.g., sites of the Ocean Color component of the AErosol RObotic NETwork- AERONET-OC), moorings (e.g, Marine Optical Buoy-MOBY), ships or autonomous vehicles (such as Autonomous Underwater Vehicles and/or Gliders).

A Satellite Mortality Study to Support Space Systems Lifetime Prediction

Science.gov (United States)

Fox, George; Salazar, Ronald; Habib-Agahi, Hamid; Dubos, Gregory

2013-01-01

Estimating the operational lifetime of satellites and spacecraft is a complex process. Operational lifetime can differ from mission design lifetime for a variety of reasons. Unexpected mortality can occur due to human errors in design and fabrication, to human errors in launch and operations, to random anomalies of hardware and software or even satellite function degradation or technology change, leading to unrealized economic or mission return. This study focuses on data collection of public information using, for the first time, a large, publically available dataset, and preliminary analysis of satellite lifetimes, both operational lifetime and design lifetime. The objective of this study is the illustration of the relationship of design life to actual lifetime for some representative classes of satellites and spacecraft. First, a Weibull and Exponential lifetime analysis comparison is performed on the ratio of mission operating lifetime to design life, accounting for terminated and ongoing missions. Next a Kaplan-Meier survivor function, standard practice for clinical trials analysis, is estimated from operating lifetime. Bootstrap resampling is used to provide uncertainty estimates of selected survival probabilities. This study highlights the need for more detailed databases and engineering reliability models of satellite lifetime that include satellite systems and subsystems, operations procedures and environmental characteristics to support the design of complex, multi-generation, long-lived space systems in Earth orbit.

Energy Analysis Program 1990 annual report

Energy Technology Data Exchange (ETDEWEB)

1992-01-01

The Energy Analysis Program has played an active role in the analysis and discussion of energy and environmental issues at several levels. (1) at the international level, with programs as developing scenarios for long-term energy demand in developing countries and organizing leading an analytic effort, ``Energy Efficiency, Developing Countries, and Eastern Europe,`` part of a major effort to increase support for energy efficiency programs worldwide; (2) at national level, the Program has been responsible for assessing energy forecasts and policies affecting energy use (e.g., appliance standards, National Energy Strategy scenarios); and (3) at the state and utility levels, the Program has been a leader in promoting integrated resource utility planning; the collaborative process has led to agreement on a new generation of utility demand-site programs in California, providing an opportunity to use knowledge and analytic techniques of the Program`s researchers. We continue to place highest on analyzing energy efficiency, with particular attention given to energy use in buildings. The Program continues its active analysis of international energy issues in Asia (including China), the Soviet Union, South America, and Western Europe. Analyzing the costs and benefits of different levels of standards for residential appliances continues to be the largest single area of research within the Program. The group has developed and applied techniques for forecasting energy demand (or constructing scenarios) for the United States. We have built a new model of industrial energy demand, are in the process of making major changes in our tools for forecasting residential energy demand, have built an extensive and documented energy conservation supply curve of residential energy use, and are beginning an analysis of energy-demand forecasting for commercial buildings.

Geomagnetic field models for satellite angular motion studies

Science.gov (United States)

Ovchinnikov, M. Yu.; Penkov, V. I.; Roldugin, D. S.; Pichuzhkina, A. V.

2018-03-01

Four geomagnetic field models are discussed: IGRF, inclined, direct and simplified dipoles. Geomagnetic induction vector expressions are provided in different reference frames. Induction vector behavior is compared for different models. Models applicability for the analysis of satellite motion is studied from theoretical and engineering perspectives. Relevant satellite dynamics analysis cases using analytical and numerical techniques are provided. These cases demonstrate the benefit of a certain model for a specific dynamics study. Recommendations for models usage are summarized in the end.

Testing the gravitational interaction in the field of the Earth via satellite laser ranging and the Laser Ranged Satellites Experiment (LARASE)

International Nuclear Information System (INIS)

Lucchesi, D M; Peron, R; Visco, M; Anselmo, L; Pardini, C; Bassan, M; Pucacco, G

2015-01-01

In this work, the Laser Ranged Satellites Experiment (LARASE) is presented. This is a research program that aims to perform new refined tests and measurements of gravitation in the field of the Earth in the weak field and slow motion (WFSM) limit of general relativity (GR). For this objective we use the free available data relative to geodetic passive satellite lasers tracked from a network of ground stations by means of the satellite laser ranging (SLR) technique. After a brief introduction to GR and its WFSM limit, which aims to contextualize the physical background of the tests and measurements that LARASE will carry out, we focus on the current limits of validation of GR and on current constraints on the alternative theories of gravity that have been obtained with the precise SLR measurements of the two LAGEOS satellites performed so far. Afterward, we present the scientific goals of LARASE in terms of upcoming measurements and tests of relativistic physics. Finally, we introduce our activities and we give a number of new results regarding the improvements to the modelling of both gravitational and non-gravitational perturbations to the orbit of the satellites. These activities are a needed prerequisite to improve the forthcoming new measurements of gravitation. An innovation with respect to the past is the specialization of the models to the LARES satellite, especially for what concerns the modelling of its spin evolution, the neutral drag perturbation and the impact of Earth's solid tides on the satellite orbit. (paper)

Engineering a responsive, low cost, tactical satellite, TACSAT-1

Science.gov (United States)

Hurley, M.; Duffey, T.; Huffine, Christopher; Weldy, Ken; Clevland, Jeff; Hauser, Joe

2004-11-01

The Secretary of Defense's Office of Force Transformation (OFT) is currently undertaking an initiative to develop a low-cost, responsive, operationally relevant space capability using small satellites. The Naval Research Laboratory (NRL) is tasked to be program manger for this initiative, which seeks to make space assets and capabilities available to operational users. TacSat-1 is the first in a series of small satellites that will result in rapid, tailored, and operationally relevant experimental space capabilities for tactical forces. Components of the resulting tactical architecture include a highly automated small satellite bus, modular payloads, common launch and payload interfaces, tasking and data dissemination using the SIPRNET (Secret Internet Protocol Routing Network), and low cost, rapid response launches. The overall goal of TacSat-1 is to demonstrate the utility of a broader complementary business model and provide a catalyst for energizing DoD and industry in the operational space area. This paper first provides a brief overview of the TacSat- 1 experiment and then discusses the engineering designs and practices used to achieve the aggressive cost and schedule goals. Non-standard approaches and engineering philosophies that allowed the TacSat-1 spacecraft to be finished in twelve months are detailed and compared with "normal" satellite programs where applicable. Specific subsystem design, integration and test techniques, which contributed to the successful completion of the TacSat-1 spacecraft, are reviewed. Finally, lessons learned are discussed.

Exploring Modular Architecture for Nano Satellite and Opportunity for Developing Countries

Science.gov (United States)

Rhaman, M. K.; Monowar, M. I.; Shakil, S. R.; Kafi, A. H.; Antara, R. S. I.

2015-01-01

SPACE Technology has the potential to provide information, infrastructure and inspiration that meets national needs in developing countries like Bangladesh. Many countries recognize this; in response they are investing in new national satellite programs to harness satellite services. Technology related to space is one example of a tool that can contribute to development both by addressing societal challenges and by advancing a nation's technological capability. To cope up with the advanced world in space technology Bangladesh seems to be highly potential country for satellite, Robotics, embedded systems and renewable energy research. BRAC University, Bangladesh is planning to launch a nano satellite with the collaboration of KIT, Japan. The proposed nano satellite project mission is to experiment about social, commercial and agricultural survey needs in Bangladesh. Each of the proposed applications of the project will improve the lives of millions of people of Bangladesh and it will be a pathfinder mission for the people of this country. Another intention of this project is to create a cheap satellite based remote sensing for developing countries as the idea of large space systems is very costly for us therefore we have decided to make a Nano-satellite.

Exploring Modular Architecture for Nano Satellite and Opportunity for Developing Countries

International Nuclear Information System (INIS)

Rhaman, M K; Monowar, M I; Shakil, S R; Kafi, A H; Antara, R S I

2015-01-01

SPACE Technology has the potential to provide information, infrastructure and inspiration that meets national needs in developing countries like Bangladesh. Many countries recognize this; in response they are investing in new national satellite programs to harness satellite services. Technology related to space is one example of a tool that can contribute to development both by addressing societal challenges and by advancing a nation's technological capability. To cope up with the advanced world in space technology Bangladesh seems to be highly potential country for satellite, Robotics, embedded systems and renewable energy research. BRAC University, Bangladesh is planning to launch a nano satellite with the collaboration of KIT, Japan. The proposed nano satellite project mission is to experiment about social, commercial and agricultural survey needs in Bangladesh. Each of the proposed applications of the project will improve the lives of millions of people of Bangladesh and it will be a pathfinder mission for the people of this country. Another intention of this project is to create a cheap satellite based remote sensing for developing countries as the idea of large space systems is very costly for us therefore we have decided to make a Nano-satellite

Conducting a SWOT Analysis for Program Improvement

Science.gov (United States)

Orr, Betsy

2013-01-01

A SWOT (strengths, weaknesses, opportunities, and threats) analysis of a teacher education program, or any program, can be the driving force for implementing change. A SWOT analysis is used to assist faculty in initiating meaningful change in a program and to use the data for program improvement. This tool is useful in any undergraduate or degree…

University Satellite Consortium and Space Education in Japan Centered on Micro-Nano Satellites

Science.gov (United States)

Nakasuka, S.; Kawashima, R.

2002-01-01

in Japan especially centered on micro or nano class satellites. Hands-on training using micro-nano satellites provide unique opportunity of space education to university level students, by giving them a chance to experience the whole space project cycle from mission creation, satellite design, fabrication, test, launch, operation through analysis of the results. Project management and team working are other important skills that can be trained in these projects. include 1) low cost, which allows one laboratory in university to carry out a project, 2) short development period such as one or two year, which enables students to obtain the results of their projects before they graduate, and 3) small size and weight, which enables fabrication and test within usually very narrow university laboratory areas. In Japan, several projects such as CanSat, CubeSat or Whale Observation Satellite have been carried out, proving that micro-nano satellites provide very unique and valuable educational opportunity. with the objective to make a university student and staff community of these micro-nano satellite related activities in Japan. This consortium aims for many activities including facilitating information and skills exchange and collaborations between member universities, helping students to use ground test facilities of national laboratories, consulting them on political or law related matters, coordinating joint development of equipments or projects, and bridging between these university activities and the needs or interests of the people in general. This kind of outreach activity is essential because how to create missions of micro-nano satellites should be pursued in order for this field to grow larger than a merely educational enterprise. The final objectives of the consortium is to make a huge community of the users, mission creators, investors and manufactures(i.e., university students) of micro-nano satellites, and provide a unique contribution to the activation of

A computer program for activation analysis

International Nuclear Information System (INIS)

Rantanen, J.; Rosenberg, R.J.

1983-01-01

A computer program for calculating the results of activation analysis is described. The program comprises two gamma spectrum analysis programs, STOAV and SAMPO and one program for calculating elemental concentrations, KVANT. STOAV is based on a simple summation of channels and SAMPO is based on fitting of mathematical functions. The programs are tested by analyzing the IAEA G-1 test spectra. In the determination of peak location SAMPO is somewhat better than STOAV and in the determination of peak area SAMPO is more than twice as accurate as STOAV. On the other hand, SAMPO is three times as expensive as STOAV with the use of a Cyber 170 computer. (author)

A Correlated Study of the Response of a Satellite to Acoustic Radiation Using Statistical Energy Analysis and Acoustic Test Data

International Nuclear Information System (INIS)

CAP, JEROME S.; TRACEY, BRIAN

1999-01-01

Aerospace payloads, such as satellites, are subjected to vibroacoustic excitation during launch. Sandia's MTI satellite has recently been certified to this environment using a combination of base input random vibration and reverberant acoustic noise. The initial choices for the acoustic and random vibration test specifications were obtained from the launch vehicle Interface Control Document (ICD). In order to tailor the random vibration levels for the laboratory certification testing, it was necessary to determine whether vibration energy was flowing across the launch vehicle interface from the satellite to the launch vehicle or the other direction. For frequencies below 120 Hz this issue was addressed using response limiting techniques based on results from the Coupled Loads Analysis (CLA). However, since the CLA Finite Element Analysis FEA model was only correlated for frequencies below 120 Hz, Statistical Energy Analysis (SEA) was considered to be a better choice for predicting the direction of the energy flow for frequencies above 120 Hz. The existing SEA model of the launch vehicle had been developed using the VibroAcoustic Payload Environment Prediction System (VAPEPS) computer code[1]. Therefore, the satellite would have to be modeled using VAPEPS as well. As is the case for any computational model, the confidence in its predictive capability increases if one can correlate a sample prediction against experimental data. Fortunately, Sandia had the ideal data set for correlating an SEA model of the MTI satellite--the measured response of a realistic assembly to a reverberant acoustic test that was performed during MTI's qualification test series. The first part of this paper will briefly describe the VAPEPS modeling effort and present the results of the correlation study for the VAPEPS model. The second part of this paper will present the results from a study that used a commercial SEA software package[2] to study the effects of in-plane modes and to evaluate

Landsat satellite evidence of the decline of northern California bull kelp

Science.gov (United States)

Renshaw, A.; Houskeeper, H. F.; Kudela, R. M.

2017-12-01

Bull kelp (Nereocystis luetkeana), a species of canopy-forming brown macroalga dominant in the Pacific Northwest of North America, provides critical ecological services such as habitat for a diverse array of marine species, nutrient regulation, photosynthesis, and regional marine carbon cycling. Starting around 2014, annual aerial surveys of bull kelp forests along California's northern coastline conducted by the California Department of Fish and Wildlife (CDFW) have reported a sudden 93% reduction in bull kelp canopy area. Remote sensing using satellite imagery is a robust, highly accurate tool for detecting and quantifying the abundance of the canopy-forming giant kelp, Macrocystis pyrifera; however, it has not been successfully applied to measuring northern bull kelp forests. One of the main difficulties associated with bull kelp detection via satellite is the small surface area of bull kelp canopies. As a result, bull kelp beds often only constitute part of a satellite pixel, making it difficult to obtain a kelp reflectance signal significantly different than water's reflectance signal. As part of the NASA Student Airborne Research Program (SARP), we test a novel method for assessing bull kelp canopy using a multiple endmember spectral mixing analysis (MESMA) applied to Landsat 5 and Landsat 8 imagery from 2003-2016. Water and kelp spectral endmembers are selected along the northern California coastline from Havens Neck cape to Point Arena. MESMA results are ground truthed with the CDFW aerial multispectral imagery data. This project will present a satellite-based time series of bull kelp canopy area and evaluate canopy change in a northern California kelp ecosystem.

Satellite-Based Precipitation Datasets

Science.gov (United States)

Munchak, S. J.; Huffman, G. J.

2017-12-01

Of the possible sources of precipitation data, those based on satellites provide the greatest spatial coverage. There is a wide selection of datasets, algorithms, and versions from which to choose, which can be confusing to non-specialists wishing to use the data. The International Precipitation Working Group (IPWG) maintains tables of the major publicly available, long-term, quasi-global precipitation data sets (http://www.isac.cnr.it/ ipwg/data/datasets.html), and this talk briefly reviews the various categories. As examples, NASA provides two sets of quasi-global precipitation data sets: the older Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) and current Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (GPM) mission (IMERG). Both provide near-real-time and post-real-time products that are uniformly gridded in space and time. The TMPA products are 3-hourly 0.25°x0.25° on the latitude band 50°N-S for about 16 years, while the IMERG products are half-hourly 0.1°x0.1° on 60°N-S for over 3 years (with plans to go to 16+ years in Spring 2018). In addition to the precipitation estimates, each data set provides fields of other variables, such as the satellite sensor providing estimates and estimated random error. The discussion concludes with advice about determining suitability for use, the necessity of being clear about product names and versions, and the need for continued support for satellite- and surface-based observation.

An Analysis of Military Use of Commercial Satellite Communications

National Research Council Canada - National Science Library

Forest, Benjamin D

2008-01-01

Since the Gulf War of 1991, United States military satellite communication (SATCOM) bandwidth demand has increased dramatically, as evidenced by recent usage rates in Operation Enduring Freedom and Operation Iraqi Freedom...

An Innovative Metric to Evaluate Satellite Precipitation's Spatial Distribution

Science.gov (United States)

Liu, H.; Chu, W.; Gao, X.; Sorooshian, S.

2011-12-01

Thanks to its capability to cover the mountains, where ground measurement instruments cannot reach, satellites provide a good means of estimating precipitation over mountainous regions. In regions with complex terrains, accurate information on high-resolution spatial distribution of precipitation is critical for many important issues, such as flood/landslide warning, reservoir operation, water system planning, etc. Therefore, in order to be useful in many practical applications, satellite precipitation products should possess high quality in characterizing spatial distribution. However, most existing validation metrics, which are based on point/grid comparison using simple statistics, cannot effectively measure satellite's skill of capturing the spatial patterns of precipitation fields. This deficiency results from the fact that point/grid-wised comparison does not take into account of the spatial coherence of precipitation fields. Furth more, another weakness of many metrics is that they can barely provide information on why satellite products perform well or poor. Motivated by our recent findings of the consistent spatial patterns of the precipitation field over the western U.S., we developed a new metric utilizing EOF analysis and Shannon entropy. The metric can be derived through two steps: 1) capture the dominant spatial patterns of precipitation fields from both satellite products and reference data through EOF analysis, and 2) compute the similarities between the corresponding dominant patterns using mutual information measurement defined with Shannon entropy. Instead of individual point/grid, the new metric treat the entire precipitation field simultaneously, naturally taking advantage of spatial dependence. Since the dominant spatial patterns are shaped by physical processes, the new metric can shed light on why satellite product can or cannot capture the spatial patterns. For demonstration, a experiment was carried out to evaluate a satellite

Probabilistic Output Analysis by Program Manipulation

DEFF Research Database (Denmark)

Rosendahl, Mads; Kirkeby, Maja Hanne

2015-01-01

The aim of a probabilistic output analysis is to derive a probability distribution of possible output values for a program from a probability distribution of its input. We present a method for performing static output analysis, based on program transformation techniques. It generates a probability...

Analysis of Software Development Methodologies to Build Safety Software Applications for the SATEX-II: A Mexican Experimental Satellite

Science.gov (United States)

Aguilar Cisneros, Jorge; Vargas Martinez, Hector; Pedroza Melendez, Alejandro; Alonso Arevalo, Miguel

2013-09-01

Mexico is a country where the experience to build software for satellite applications is beginning. This is a delicate situation because in the near future we will need to develop software for the SATEX-II (Mexican Experimental Satellite). SATEX- II is a SOMECyTA's project (the Mexican Society of Aerospace Science and Technology). We have experienced applying software development methodologies, like TSP (Team Software Process) and SCRUM in other areas. Then, we analyzed these methodologies and we concluded: these can be applied to develop software for the SATEX-II, also, we supported these methodologies with SSP-05-0 Standard in particular with ESA PSS-05-11. Our analysis was focusing on main characteristics of each methodology and how these methodologies could be used with the ESA PSS 05-0 Standards. Our outcomes, in general, may be used by teams who need to build small satellites, but, in particular, these are going to be used when we will build the on board software applications for the SATEX-II.

Real-time monitoring of seismic data using satellite telemetry

Directory of Open Access Journals (Sweden)

L. Merucci

1997-06-01

Full Text Available This article describes the ARGO Satellite Seismic Network (ARGO SSN as a reliable system for monitoring, collection, visualisation and analysis of seismic and geophysical low-frequency data, The satellite digital telemetry system is composed of peripheral geophysical stations, a centraI communications node (master sta- tion located in CentraI Italy, and a data collection and processing centre located at ING (Istituto Nazionale di Geofisica, Rome. The task of the peripheral stations is to digitalise and send via satellite the geophysical data collected by the various sensors to the master station. The master station receives the data and forwards them via satellite to the ING in Rome; it also performs alI the monitoring functions of satellite communications. At the data collection and processing centre of ING, the data are received and analysed in real time, the seismic events are identified and recorded, the low-frequency geophysical data are stored. In addition, the generaI sta- tus of the satellite network and of each peripheral station connected, is monitored. The procedure for analysjs of acquired seismic signals allows the automatic calculation of local magnitude and duration magnitude The communication and data exchange between the seismic networks of Greece, Spain and Italy is the fruit of a recent development in the field of technology of satellite transmission of ARGO SSN (project of European Community "Southern Europe Network for Analysis of Seismic Data"

Nonlinear programming analysis and methods

CERN Document Server

Avriel, Mordecai

2012-01-01

This text provides an excellent bridge between principal theories and concepts and their practical implementation. Topics include convex programming, duality, generalized convexity, analysis of selected nonlinear programs, techniques for numerical solutions, and unconstrained optimization methods.

Energy Analysis Program 1990 annual report

International Nuclear Information System (INIS)

1992-01-01

The Energy Analysis Program has played an active role in the analysis and discussion of energy and environmental issues at several levels. (1) at the international level, with programs as developing scenarios for long-term energy demand in developing countries and organizing leading an analytic effort, ''Energy Efficiency, Developing Countries, and Eastern Europe,'' part of a major effort to increase support for energy efficiency programs worldwide; (2) at national level, the Program has been responsible for assessing energy forecasts and policies affecting energy use (e.g., appliance standards, National Energy Strategy scenarios); and (3) at the state and utility levels, the Program has been a leader in promoting integrated resource utility planning; the collaborative process has led to agreement on a new generation of utility demand-site programs in California, providing an opportunity to use knowledge and analytic techniques of the Program's researchers. We continue to place highest on analyzing energy efficiency, with particular attention given to energy use in buildings. The Program continues its active analysis of international energy issues in Asia (including China), the Soviet Union, South America, and Western Europe. Analyzing the costs and benefits of different levels of standards for residential appliances continues to be the largest single area of research within the Program. The group has developed and applied techniques for forecasting energy demand (or constructing scenarios) for the United States. We have built a new model of industrial energy demand, are in the process of making major changes in our tools for forecasting residential energy demand, have built an extensive and documented energy conservation supply curve of residential energy use, and are beginning an analysis of energy-demand forecasting for commercial buildings

Analysis on the status of the application of satellite remote sensing technology to nuclear safeguards

International Nuclear Information System (INIS)

Tao Zhangsheng; Zhao Yingjun

2008-01-01

Based on the application status of satellite remote sensing technology to nuclear safeguards, advantage of satellite remote sensing technology is analyzed, main types of satellite image used in nuclear safeguards are elaborated and the main application of satellite images is regarded to detect, verify and monitor nuclear activities; verify additional protocol declaration and design information, support performing complementary access inspections; investigate alleged undeclared activities based on open source or the third party information. Application examples of satellite image in nuclear safeguards to analyze nuclear facilities by other countries, the ability of remote sensing technology in nuclear safeguards is discussed. (authors)

Initial results of centralized autonomous orbit determination of the new-generation BDS satellites with inter-satellite link measurements

Science.gov (United States)

Tang, Chengpan; Hu, Xiaogong; Zhou, Shanshi; Liu, Li; Pan, Junyang; Chen, Liucheng; Guo, Rui; Zhu, Lingfeng; Hu, Guangming; Li, Xiaojie; He, Feng; Chang, Zhiqiao

2018-01-01

Autonomous orbit determination is the ability of navigation satellites to estimate the orbit parameters on-board using inter-satellite link (ISL) measurements. This study mainly focuses on data processing of the ISL measurements as a new measurement type and its application on the centralized autonomous orbit determination of the new-generation Beidou navigation satellite system satellites for the first time. The ISL measurements are dual one-way measurements that follow a time division multiple access (TDMA) structure. The ranging error of the ISL measurements is less than 0.25 ns. This paper proposes a derivation approach to the satellite clock offsets and the geometric distances from TDMA dual one-way measurements without a loss of accuracy. The derived clock offsets are used for time synchronization, and the derived geometry distances are used for autonomous orbit determination. The clock offsets from the ISL measurements are consistent with the L-band two-way satellite, and time-frequency transfer clock measurements and the detrended residuals vary within 0.5 ns. The centralized autonomous orbit determination is conducted in a batch mode on a ground-capable server for the feasibility study. Constant hardware delays are present in the geometric distances and become the largest source of error in the autonomous orbit determination. Therefore, the hardware delays are estimated simultaneously with the satellite orbits. To avoid uncertainties in the constellation orientation, a ground anchor station that "observes" the satellites with on-board ISL payloads is introduced into the orbit determination. The root-mean-square values of orbit determination residuals are within 10.0 cm, and the standard deviation of the estimated ISL hardware delays is within 0.2 ns. The accuracy of the autonomous orbits is evaluated by analysis of overlap comparison and the satellite laser ranging (SLR) residuals and is compared with the accuracy of the L-band orbits. The results indicate

Analysis of computer programming languages

International Nuclear Information System (INIS)

Risset, Claude Alain

1967-01-01

This research thesis aims at trying to identify some methods of syntax analysis which can be used for computer programming languages while putting aside computer devices which influence the choice of the programming language and methods of analysis and compilation. In a first part, the author proposes attempts of formalization of Chomsky grammar languages. In a second part, he studies analytical grammars, and then studies a compiler or analytic grammar for the Fortran language

Satellite Power System (SPS) financial/management scenarios

Science.gov (United States)

Vajk, J. P.

1978-01-01

The possible benefits of a Satellite Power System (SPS) program, both domestically and internationally, justify detailed and imaginative investigation of the issues involved in financing and managing such a large-scale program. In this study, ten possible methods of financing a SPS program are identified ranging from pure government agency to private corporations. The following were analyzed and evaluated: (1) capital requirements for SPS; (2) ownership and control; (3) management principles; (4) organizational forms for SPS; (5) criteria for evaluation; (6) detailed description and preliminary evaluation of alternatives; (7) phased approaches; and (8) comparative evaluation. Key issues and observations and recommendations for further study are also presented.

Small astronomy satellite-A, Uhuru data analysis

Science.gov (United States)

Koch, D.

1974-01-01

Objectives were to conduct observations with the first satellite entirely devoted to X-ray astronomy and to analyze the results obtained. A catalog of X-ray sources was generated, and results of discoveries and further detailed observations of sources were presented in scientific journals and meetings. A list of how objectives were met, a brief description of the instrument, significant results, the X-ray catalog, and a complete bibliography of results are included.

Robust Satellite Techniques analysis of ten years (2004-2013) of MSG/SEVIRI TIR radiances over Greece region

Science.gov (United States)

Genzano, N.; Eleftheriou, A.; Filizzola, C.; Paciello, R.; Pergola, N.; Vallianatos, F.; Tramutoli, V.

2014-12-01

Space-time fluctuations of Earth's emitted Thermal InfraRed (TIR) radiation have been observed from satellite months to weeks before earthquakes occurrence. Among the different approach proposed to discern transient anomalous signals possibly associated to seismic activity from normal TIR signal fluctuations (i.e. related to the change of natural factor and/or observation conditions), since 2001 the Robust Satellite Techniques (RST) were used to investigate tens of earthquakes with a wide range of magnitudes (from 4.0 to 7.9) occurred in different continents and in various geo-tectonic setting (e.g. Athens earthquake, 7 September 1999; Abruzzo earthquake, 6 April 2009, etc.).The RST approach gives a statistically - based definition of "TIR anomalies" and offers a suitable method for their identification even in very different local (e.g. related to atmosphere and/or surface) and observational (e.g. related to time/season, but also to solar and satellite zenithal angles) conditions. It has been always carried out by using a validation/confutation approach, to verify the presence/absence of anomalous space-time TIR transients in the presence/absence of seismic activity.In this paper, the RST approach is extensively implemented on 10 years of TIR satellite records collected by the geostationary satellite sensor MSG/SEVIRI over the Greece region. The results of the analysis performed to investigate possible correlations (within predefined space-time windows) of anomalous TIR transients with time and place of occurrence of earthquakes with M>4 will be discussed in terms of reliability and effectiveness also in the perspective of a time-Dependent Assessment of Seismic Hazard (t-DASH) system.

Assessment of different topographic corrections in AWiFS satellite ...

Indian Academy of Sciences (India)

Snow and Avalanche Study Establishment, Defence Research and Development Organisation,. Chandigarh 160 ... IRS P6 satellite images and the qualitative and quantitative comparative analysis in detail. Both .... Top: AWiFS satellite image of Western Himalaya and bottom: zoom image of the study area shown with white.

Meteorological satellite systems

CERN Document Server

Tan, Su-Yin

2014-01-01

“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.

Prediction of GNSS satellite clocks

International Nuclear Information System (INIS)

Broederbauer, V.

2010-01-01

This thesis deals with the characterisation and prediction of GNSS-satellite-clocks. A prerequisite to develop powerful algorithms for the prediction of clock-corrections is the thorough study of the behaviour of the different clock-types of the satellites. In this context the predicted part of the IGU-clock-corrections provided by the Analysis Centers (ACs) of the IGS was compared to the IGS-Rapid-clock solutions to determine reasonable estimates of the quality of already existing well performing predictions. For the shortest investigated interval (three hours) all ACs obtain almost the same accuracy of 0,1 to 0,4 ns. For longer intervals the individual predictions results start to diverge. Thus, for a 12-hours- interval the differences range from nearly 10 ns (GFZ, CODE) until up to some 'tens of ns'. Based on the estimated clock corrections provided via the IGS Rapid products a simple quadratic polynomial turns out to be sufficient to describe the time series of Rubidium-clocks. On the other hand Cesium-clocks show a periodical behaviour (revolution period) with an amplitude of up to 6 ns. A clear correlation between these amplitudes and the Sun elevation angle above the orbital planes can be demonstrated. The variability of the amplitudes is supposed to be caused by temperature-variations affecting the oscillator. To account for this periodical behaviour a quadratic polynomial with an additional sinus-term was finally chosen as prediction model both for the Cesium as well as for the Rubidium clocks. The three polynomial-parameters as well as amplitude and phase shift of the periodic term are estimated within a least-square-adjustment by means of program GNSS-VC/static. Input-data are time series of the observed part of the IGU clock corrections. With the estimated parameters clock-corrections are predicted for various durations. The mean error of the prediction of Rubidium-clock-corrections for an interval of six hours reaches up to 1,5 ns. For the 12-hours

Monitoring sea level and sea surface temperature trends from ERS satellites

DEFF Research Database (Denmark)

Andersen, Ole Baltazar; Knudsen, Per; Beckley, B.

2002-01-01

Data from the two ESA satellites ERS-1 and ERS-2 are used in global and regional analysis of sea level and sea surface temperature trends over the last, 7.8 years. T he ERS satellites and in the future the ENVISAT satellite provide unique opportunity for monitoring both changes in sea level and sea...

GUST86 - An analytical ephemeris of the Uranian satellites. [General Uranus Satellite Theory

Science.gov (United States)

Laskar, J.; Jacobson, R. A.

1987-01-01

The General Uranus Satellite Theory GUST (Laskar, 1986) is used for the construction of an analytical ephemeris for the Uranian satellites. The theory is fitted against earth-based observations from 1911 to 1986, and all radio and optical data obtained during Voyager encounter with Uranus. Earth-based observations alone allow the determination of masses which are within 15 percent of the values determined by the Uranus flyby. The analysis of all the observations confirm the values of the masses obtained during the encounter (Stone and Miner, 1986) and give a complete set of dynamical parameters for the analytical theory. An analytical ephemeris, GUST86, with an estimated precision of about 100 km with respect to Uranus is obtained.

Ionospheric response to daytime auroral electron precipitation: Results and analysis of a coordinated experiment between the AUREOL-3 satellite and the EISCAT radar

International Nuclear Information System (INIS)

Stamnes, K.; Roble, R.G.

1986-01-01

On June 2, 1982 the Soviet-French polar orbiting satellite AUREOL-3 passed over the EISCAT facility in northern Scandinavia. The EISCAT UHF radar measured electron and ion temperatures, electron density and ion composition, while the satellite measured the incident auroral particle spectra (protons and electrons) presumably giving rise to the densities and temperatures inferred from the radar data. The link between the satellite data obtained well above the atmosphere (at about 1300 km), and the radar measurements is an auroral model that simulates the ionospheric response to auroral particle precipitation and solar EUV radiation and makes predictions of ionospheric properties that 1) can be measured by the radar and 2) are the consequence of the satellite-observed particle precipitation. The analysis shows that there is good agreement between model-predicted and radar-inferred electron and ion temperatures and ion composition. However, inference of the ion composition from the radar data is a non-trivial and time-consuming undertaking which requires very good data (i.e. long integration times). Our initial attempts at analyzing the radar data with a fixed ion composition (as commonly practiced) which greatly simplifies the analysis yielded poor agreement between model predictions and radar measurements. Thus, our analysis demonstrates that the proper ion composition is crucial in order to obtain reliable temperature and density results from the measured autocorrelation functions

Multi-satellite observations of magnetic fields in space plasmas

International Nuclear Information System (INIS)

Potemra, T.A.; Zanetti, L.J.; Bythrow, P.F.; Erlandson, R.E.

1987-01-01

The most common method of detecting electric currents in space has been by virtue of the magnetic perturbations they produce. A satellite can pass through a field-aligned ''Birkeland'' current and measure the in-situ magnetic perturbations. Satellite-borne magnetic field experiments may also be used to observe characteristics of resonant oscillations of the Earth's magnetic field at ULF frequencies. Examples of such measurements with magnetic field experiments on the Viking, AMPTE/CCE, and DMSP-F7 satellites will be presented. The Viking satellite, launched in February, 1986, is Sweden's first satellite and is in a polar orbit with 3.1 R/sub e/ apogee. AMPTE/CCE was launched in August, 1984, with satellites from West Germany and the United Kingdom, for the purpose of creating artificial comets in space. It is in an equatorial orbit with a 8.8 R/sub e/ apogee. The Defense Meteorological Satellite Program (DMSP)-F7 satellite was launched in October, 1983 into an 800 km circular sun-synchronous orbit in the 0830-2030 magnetic local time plane. Viking and AMPTE/CCE observed harmonic ULF pulsations when they were near the same flux tube, but separated by about 10 R/sub e/. These unique observations are used to investigate the characteristics and sources of multiple field line resonances of Alfven waves. On another occasion, Viking and DMSP-F7 observed similar magnetic perturbations at widely separated locations. The authors interpret these perturbations as due to a complicated system of large-scale stable Birkeland currents in the morning sector. This multi-satellite data set is in the early stages of exploration, but already confirms the usefulness of coordinated multi-position observations of magnetic fields in space

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

Science.gov (United States)

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

2004-01-01

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 (trmm.gsfc.nasa.gov) 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.

Energy Analysis Program 1990 annual report

Energy Technology Data Exchange (ETDEWEB)

1992-01-01

The Energy Analysis Program has played an active role in the analysis and discussion of energy and environmental issues at several levels. (1) at the international level, with programs as developing scenarios for long-term energy demand in developing countries and organizing leading an analytic effort, Energy Efficiency, Developing Countries, and Eastern Europe,'' part of a major effort to increase support for energy efficiency programs worldwide; (2) at national level, the Program has been responsible for assessing energy forecasts and policies affecting energy use (e.g., appliance standards, National Energy Strategy scenarios); and (3) at the state and utility levels, the Program has been a leader in promoting integrated resource utility planning; the collaborative process has led to agreement on a new generation of utility demand-site programs in California, providing an opportunity to use knowledge and analytic techniques of the Program's researchers. We continue to place highest on analyzing energy efficiency, with particular attention given to energy use in buildings. The Program continues its active analysis of international energy issues in Asia (including China), the Soviet Union, South America, and Western Europe. Analyzing the costs and benefits of different levels of standards for residential appliances continues to be the largest single area of research within the Program. The group has developed and applied techniques for forecasting energy demand (or constructing scenarios) for the United States. We have built a new model of industrial energy demand, are in the process of making major changes in our tools for forecasting residential energy demand, have built an extensive and documented energy conservation supply curve of residential energy use, and are beginning an analysis of energy-demand forecasting for commercial buildings.

ESA personal communications and digital audio broadcasting systems based on non-geostationary satellites

Science.gov (United States)

Logalbo, P.; Benedicto, J.; Viola, R.

1993-01-01

Personal Communications and Digital Audio Broadcasting are two new services that the European Space Agency (ESA) is investigating for future European and Global Mobile Satellite systems. ESA is active in promoting these services in their various mission options including non-geostationary and geostationary satellite systems. A Medium Altitude Global Satellite System (MAGSS) for global personal communications at L and S-band, and a Multiregional Highly inclined Elliptical Orbit (M-HEO) system for multiregional digital audio broadcasting at L-band are described. Both systems are being investigated by ESA in the context of future programs, such as Archimedes, which are intended to demonstrate the new services and to develop the technology for future non-geostationary mobile communication and broadcasting satellites.

The Y2K program for scientific-analysis computer programs at AECL

International Nuclear Information System (INIS)

Popovic, J.; Gaver, C.; Chapman, D.

1999-01-01

The evaluation of scientific-analysis computer programs for year-2000 compliance is part of AECL' s year-2000 (Y2K) initiative, which addresses both the infrastructure systems at AECL and AECL's products and services. This paper describes the Y2K-compliance program for scientific-analysis computer codes. This program involves the integrated evaluation of the computer hardware, middleware, and third-party software in addition to the scientific codes developed in-house. The project involves several steps: the assessment of the scientific computer programs for Y2K compliance, performing any required corrective actions, porting the programs to Y2K-compliant platforms, and verification of the programs after porting. Some programs or program versions, deemed no longer required in the year 2000 and beyond, will be retired and archived. (author)

The Y2K program for scientific-analysis computer programs at AECL

International Nuclear Information System (INIS)

Popovic, J.; Gaver, C.; Chapman, D.

1999-01-01

The evaluation of scientific analysis computer programs for year-2000 compliance is part of AECL's year-2000 (Y2K) initiative, which addresses both the infrastructure systems at AECL and AECL's products and services. This paper describes the Y2K-compliance program for scientific-analysis computer codes. This program involves the integrated evaluation of the computer hardware, middleware, and third-party software in addition to the scientific codes developed in-house. The project involves several steps: the assessment of the scientific computer programs for Y2K compliance, performing any required corrective actions, porting the programs to Y2K-compliant platforms, and verification of the programs after porting. Some programs or program versions, deemed no longer required in the year 2000 and beyond, will be retired and archived. (author)

Validating Satellite-Retrieved Cloud Properties for Weather and Climate Applications

Science.gov (United States)

Minnis, P.; Bedka, K. M.; Smith, W., Jr.; Yost, C. R.; Bedka, S. T.; Palikonda, R.; Spangenberg, D.; Sun-Mack, S.; Trepte, Q.; Dong, X.; Xi, B.

2014-12-01

Cloud properties determined from satellite imager radiances are increasingly used in weather and climate applications, particularly in nowcasting, model assimilation and validation, trend monitoring, and precipitation and radiation analyses. The value of using the satellite-derived cloud parameters is determined by the accuracy of the particular parameter for a given set of conditions, such as viewing and illumination angles, surface background, and cloud type and structure. Because of the great variety of those conditions and of the sensors used to monitor clouds, determining the accuracy or uncertainties in the retrieved cloud parameters is a daunting task. Sensitivity studies of the retrieved parameters to the various inputs for a particular cloud type are helpful for understanding the errors associated with the retrieval algorithm relative to the plane-parallel world assumed in most of the model clouds that serve as the basis for the retrievals. Real world clouds, however, rarely fit the plane-parallel mold and generate radiances that likely produce much greater errors in the retrieved parameter than can be inferred from sensitivity analyses. Thus, independent, empirical methods are used to provide a more reliable uncertainty analysis. At NASA Langley, cloud properties are being retrieved from both geostationary (GEO) and low-earth orbiting (LEO) satellite imagers for climate monitoring and model validation as part of the NASA CERES project since 2000 and from AVHRR data since 1978 as part of the NOAA CDR program. Cloud properties are also being retrieved in near-real time globally from both GEO and LEO satellites for weather model assimilation and nowcasting for hazards such as aircraft icing. This paper discusses the various independent datasets and approaches that are used to assessing the imager-based satellite cloud retrievals. These include, but are not limited to data from ARM sites, CloudSat, and CALIPSO. This paper discusses the use of the various

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

Science.gov (United States)

Hoder, Douglas; Bergamo, Marcos

1996-01-01

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.

HiTempo: a platform for time-series analysis of remote-sensing satellite data in a high-performance computing environment

CSIR Research Space (South Africa)

Van den Bergh, F

2012-08-01

Full Text Available Course resolution earth observation satellites offer large data sets with daily observations at global scales. These data sets represent a rich resource that, because of the high acquisition rate, allows the application of time-series analysis...

77 FR 55783 - Verification of Statements of Account Submitted by Cable Operators and Satellite Carriers

Science.gov (United States)

2012-09-11

... the Office by cable operators and satellite carriers. Initial comments are available for review on the... Program Suppliers represent copyright owners that produce and/or syndicate movies, programs, and specials...

Planning for a data base system to support satellite conceptual design

Science.gov (United States)

Claydon, C. R.

1976-01-01

The conceptual design of an automated satellite design data base system is presented. The satellite catalog in the system includes data for all earth orbital satellites funded to the hardware stage for launch between 1970 and 1980, and provides a concise compilation of satellite capabilities and design parameters. The cost of satellite subsystems and components will be added to the base. Data elements are listed and discussed. Sensor and science and applications opportunities catalogs will be included in the data system. Capabilities of the BASIS storage, retrieval, and analysis system are used in the system design.

Programs for nuclear data analysis

International Nuclear Information System (INIS)

Bell, R.A.I.

1975-01-01

The following report details a number of programs and subroutines which are useful for analysis of data from nuclear physics experiments. Most of them are available from pool pack 005 on the IBM1800 computer. All of these programs are stored there as core loads, and the subroutines and functions in relocatable format. The nature and location of other programs are specified as appropriate. (author)

Operational Satellite-based Surface Oil Analyses (Invited)

Science.gov (United States)

Streett, D.; Warren, C.

2010-12-01

During the Deepwater Horizon spill, NOAA imagery analysts in the Satellite Analysis Branch (SAB) issued more than 300 near-real-time satellite-based oil spill analyses. These analyses were used by the oil spill response community for planning, issuing surface oil trajectories and tasking assets (e.g., oil containment booms, skimmers, overflights). SAB analysts used both Synthetic Aperture Radar (SAR) and high resolution visible/near IR multispectral satellite imagery as well as a variety of ancillary datasets. Satellite imagery used included ENVISAT ASAR (ESA), TerraSAR-X (DLR), Cosmo-Skymed (ASI), ALOS (JAXA), Radarsat (MDA), ENVISAT MERIS (ESA), SPOT (SPOT Image Corp.), Aster (NASA), MODIS (NASA), and AVHRR (NOAA). Ancillary datasets included ocean current information, wind information, location of natural oil seeps and a variety of in situ oil observations. The analyses were available as jpegs, pdfs, shapefiles and through Google, KML files and also available on a variety of websites including Geoplatform and ERMA. From the very first analysis issued just 5 hours after the rig sank through the final analysis issued in August, the complete archive is still publicly available on the NOAA/NESDIS website http://www.ssd.noaa.gov/PS/MPS/deepwater.html SAB personnel also served as the Deepwater Horizon International Disaster Charter Project Manager (at the official request of the USGS). The Project Manager’s primary responsibility was to acquire and oversee the processing and dissemination of satellite data generously donated by numerous private companies and nations in support of the oil spill response including some of the imagery described above. SAB has begun to address a number of goals that will improve our routine oil spill response as well as help assure that we are ready for the next spill of national significance. We hope to (1) secure a steady, abundant and timely stream of suitable satellite imagery even in the absence of large-scale emergencies such as

Dynamic analysis program for frame structure

International Nuclear Information System (INIS)

Ando, Kozo; Chiba, Toshio

1975-01-01

A general purpose computer program named ISTRAN/FD (Isub(HI) STRucture ANalysis/Frame structure, Dynamic analysis) has been developed for dynamic analysis of three-dimensional frame structures. This program has functions of free vibration analysis, seismic response analysis, graphic display by plotter and CRT, etc. This paper introduces ISTRAN/FD; examples of its application are shown with various problems : idealization of the cantilever, dynamic analysis of the main tower of the suspension bridge, three-dimensional vibration in the plate girder bridge, seismic response in the boiler steel structure, and dynamic properties of the underground LNG tank. In this last example, solid elements, in addition to beam elements, are especially used for the analysis. (auth.)

A program for activation analysis data processing

International Nuclear Information System (INIS)

Janczyszyn, J.; Loska, L.; Taczanowski, S.

1978-01-01

An ALGOL program for activation analysis data handling is presented. The program may be used either for single channel spectrometry data or for multichannel spectrometry. The calculation of instrumental error and of analysis standard deviation is carried out. The outliers are tested, and the regression line diagram with the related observations are plotted by the program. (author)

Shadow Analysis Technique for Extraction of Building Height using High Resolution Satellite Single Image and Accuracy Assessment

Science.gov (United States)

Raju, P. L. N.; Chaudhary, H.; Jha, A. K.

2014-11-01

These High resolution satellite data with metadata information is used to extract the height of the building using shadow. Proposed approach divides into two phases 1) rooftop and shadow extraction and 2) height estimation. Firstly the rooftop and shadow region were extracted by manual/ automatic methods using Example - Based and Rule - Based approaches. After feature extraction next step is estimating height of the building by taking rooftop in association with shadow using Ratio Method and by using the relation between sun-satellite geometry. The performance analysis shows the total mean error of height is 0.67 m from ratio method, 1.51 m from Example - Based Approach and 0.96 m from Rule - Based Approach. Analysis concluded that Ratio Method i.e. manual method is best for height estimation but it is time consuming so the automatic Rule Based approach is best for height estimation in comparison to Example Based Approach because it require more knowledge and selection of more training samples as well as slows the processing rate of the method.

From Assimilation to Kalomoira: Satellite Television and its Place in New York City’s Greek Community

Directory of Open Access Journals (Sweden)

Michael Nevradakis

2011-01-01

Full Text Available This paper examines the role that imported satellite television programming from Greece has played in the maintenance and rejuvenation of Greek cultural identity and language use within the Greek-American community of New York City—the largest and most significant in the United States. Four main concepts guide this paper, based on prior theoretical research established in the field of Diaspora studies: authenticity, assertive hybridity, cultural capital, and imagined communities. Satellite television broadcasts from Greece have targeted the audience of the Hellenic Diaspora as an extension of the homeland, and as a result, are viewed as more “authentic” than Diaspora-based broadcasts. Assertive hybridity is exemplified through satellite programming such as reality shows and the emergence of transnational pop stars such as Kalomoira, who was born and raised in New York but attained celebrity status in Greece as the result of her participation on the Greek reality show Fame Story. Finally, satellite television broadcasts from Greece have fostered the formation of a transnational imagined community, linked by the shared viewing of Greek satellite programming and the simultaneous consumption of Greek pop culture and acquisition of cultural capital. All of the above concepts are evident in the emergence of a Greek “café culture” and “sports culture”, mediated by satellite television and visible in the community’s public spaces. These findings contradict predictions often seen in the prior scholarship on the topic, which foresaw a quick erosion of Greek language use within the Greek-American community.

Assimilation of tourism satellite accounts and applied general equilibrium models to inform tourism policy analysis

OpenAIRE

Rossouw, Riaan; Saayman, Melville

2011-01-01

Historically, tourism policy analysis in South Africa has posed challenges to accurate measurement. The primary reason for this is that tourism is not designated as an 'industry' in standard economic accounts. This paper therefore demonstrates the relevance and need for applied general equilibrium (AGE) models to be completed and extended through an integration with tourism satellite accounts (TSAs) as a tool for policy makers (especially tourism policy makers) in South Africa. The paper sets...

Analysis of high-n dielectronic Rydberg satellites in the spectra of Na-like Zn XX and Mg-like Zn XIX

International Nuclear Information System (INIS)

Fournier, K.B.; Faenov, A.Ya.; Pikuz, T.A.; Magunov, A.I.; Skobelev, I.Yu.; Flora, F.; Bollanti, S.; Di Lazzaro, P.; Murra, D.; Belyaev, V.S.; Vinogradov, V.I.; Kyrilov, A.S.; Matafonov, A.P.; Francucci, M.; Martellucci, S.; Petrocelli, G.

2004-01-01

We have observed spectra from highly charged zinc ions in a variety of laser-produced plasmas. Spectral features that are Na- and Mg-like satellites to high-n Rydberg transitions in the Ne-like Zn XXI spectrum are analyzed and modeled. Identifications and analysis are made by comparison with highly accurate atomic structure calculations and steady state collisional-radiative models. Each observed Zn XX and Zn XIX feature comprises up to ≅2 dozen individual transitions, these transitions are excited principally by dielectronic recombination through autoionizing levels in Na- and Mg-like Zn 19+ and Zn 18+ . We find these satellites to be ubiquitous in laser-produced plasmas formed by lasers with pulse lengths that span four orders of magnitude, from 1 ps to ≅10 ns. The diagnostic potential of these Rydberg satellite lines is demonstrated

Centriolar satellites

DEFF Research Database (Denmark)

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

2015-01-01

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....

Production process for advanced space satellite system cables/interconnects.

Energy Technology Data Exchange (ETDEWEB)

Mendoza, Luis A.

2007-12-01

This production process was generated for the satellite system program cables/interconnects group, which in essences had no well defined production process. The driver for the development of a formalized process was based on the set backs, problem areas, challenges, and need improvements faced from within the program at Sandia National Laboratories. In addition, the formal production process was developed from the Master's program of Engineering Management for New Mexico Institute of Mining and Technology in Socorro New Mexico and submitted as a thesis to meet the institute's graduating requirements.

Mobilisation of satellite cells following ischaemia and reperfusion in ...

African Journals Online (AJOL)

Enrique

inar is not disturbed, and migration to adjacent myofibres using tissue bridges ... or in group 2, the novel observation of the satellite cell breaking away ... satellite cells of group 1 were significantly longer than the group 2 cells .... Statistical analysis was by unpaired t-test with Welch's cor- ... or fully motile, interfibre myoblasts.

Mapping and Visualization of The Deepwater Horizon Oil Spill Using Satellite Imagery

Science.gov (United States)

Ferreira Pichardo, E.

2017-12-01

Satellites are man-made objects hovering around the Earth's orbit and are essential for Earth observation, i.e. the monitoring and gathering of data about the Earth's vital systems. Environmental Satellites are used for atmospheric research, weather forecasting, and warning as well as monitoring extreme weather events. These satellites are categorized into Geosynchronous and Low Earth (Polar) orbiting satellites. Visualizing satellite data is critical to understand the Earth's systems and changes to our environment. The objective of this research is to examine satellite-based remotely sensed data that needs to be processed and rendered in the form of maps or other forms of visualization to understand and interpret the satellites' observations to monitor the status, changes and evolution of the mega-disaster Deepwater Horizon Spill that occurred on April 20, 2010 in the Gulf of Mexico. In this project, we will use an array of tools and programs such as Python, CSPP and Linux. Also, we will use data from the National Oceanic and Atmospheric Administration (NOAA): Polar-Orbiting Satellites Terra Earth Observing System AM-1 (EOS AM-1), and Aqua EOS PM-1 to investigate the mega-disaster. Each of these satellites carry a variety of instruments, and we will use the data obtained from the remote sensor Moderate-Resolution Imaging Spectroradiometer (MODIS). Ultimately, this study shows the importance of mapping and visualizing data such as satellite data (MODIS) to understand the extents of environmental impacts disasters such as the Deepwater Horizon Oil spill.

A probabilistic analysis of the implications of instrument failures on ESA's Swarm mission for its individual satellite orbit deployments

Science.gov (United States)

Jackson, Andrew

2015-07-01

On launch, one of Swarm's absolute scalar magnetometers (ASMs) failed to function, leaving an asymmetrical arrangement of redundant spares on different spacecrafts. A decision was required concerning the deployment of individual satellites into the low-orbit pair or the higher "lonely" orbit. I analyse the probabilities for successful operation of two of the science components of the Swarm mission in terms of a classical probabilistic failure analysis, with a view to concluding a favourable assignment for the satellite with the single working ASM. I concentrate on the following two science aspects: the east-west gradiometer aspect of the lower pair of satellites and the constellation aspect, which requires a working ASM in each of the two orbital planes. I use the so-called "expert solicitation" probabilities for instrument failure solicited from Mission Advisory Group (MAG) members. My conclusion from the analysis is that it is better to have redundancy of ASMs in the lonely satellite orbit. Although the opposite scenario, having redundancy (and thus four ASMs) in the lower orbit, increases the chance of a working gradiometer late in the mission; it does so at the expense of a likely constellation. Although the results are presented based on actual MAG members' probabilities, the results are rather generic, excepting the case when the probability of individual ASM failure is very small; in this case, any arrangement will ensure a successful mission since there is essentially no failure expected at all. Since the very design of the lower pair is to enable common mode rejection of external signals, it is likely that its work can be successfully achieved during the first 5 years of the mission.

Static Analysis of Functional Programs

NARCIS (Netherlands)

van den Berg, Klaas; van den Broek, P.M.

1994-01-01

In this paper, the static analysis of programs in the functional programming language Miranda is described based on two graph models. A new control-flow graph model of Miranda definitions is presented, and a model with four classes of caligraphs. Standard software metrics are applicable to these

Satellite Data Inform Forecasts of Crop Growth

Science.gov (United States)

2015-01-01

During a Stennis Space Center-led program called Ag 20/20, an engineering contractor developed models for using NASA satellite data to predict crop yield. The model was eventually sold to Genscape Inc., based in Louisville, Kentucky, which has commercialized it as LandViewer. Sold under a subscription model, LandViewer software provides predictions of corn production to ethanol plants and grain traders.

Proceedings of the Twenty-First NASA Propagation Experiments Meeting (NAPEX XXI) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

Science.gov (United States)

Golshan, Nasser (Editor)

1997-01-01

The NASA Propagation Experimenters (NAPEX) meeting is convened each year to discuss studies supported by the NASA Propagation Program. Representatives from the satellite communications industry, academia and government who have an interest in space-ground radio wave propagation are invited to NAPEX meetings for discussions and exchange of information. The reports delivered at this meeting by program managers and investigators present recent activities and future plans. This forum provides an opportunity for peer discussion of work in progress, timely dissemination of propagation results, and close interaction with the satellite communications industry. NAPEX XXI took place in El Segundo, California on June 11-12, 1997 and consisted of three sessions. Session 1, entitled "ACTS Propagation Study Results & Outcome " covered the results of 20 station-years of Ka-band radio-wave propagation experiments. Session 11, 'Ka-band Propagation Studies and Models,' provided the latest developments in modeling, and analysis of experimental results about radio wave propagation phenomena for design of Ka-band satellite communications systems. Session 111, 'Propagation Research Topics,' covered a diverse range of propagation topics of interest to the space community, including overviews of handbooks and databases on radio wave propagation. The ACTS Propagation Studies miniworkshop was held on June 13, 1997 and consisted of a technical session in the morning and a plenary session in the afternoon. The morning session covered updates on the status of the ACTS Project & Propagation Program, engineering support for ACTS Propagation Terminals, and the Data Center. The plenary session made specific recommendations for the future direction of the program.

The data processor from the small scientific satellite

Science.gov (United States)

Mccain, H. G.

1973-01-01

A reprogrammable data system aboard a small scientific satellite is described that samples and processes magnetospheric measurements for transmission to the ground. The lightweight configuration of the data system is made up of the program memory, data storage, input/output module, and a central processing unit. The system is designed for multiple missions.

Towards automated statewide land cover mapping in Wisconsin using satellite remote sensing and GIS techniques

International Nuclear Information System (INIS)

Cosentino, B.L.; Lillesand, T.M.

1991-01-01

Attention is given to an initial research project being performed by the University of Wisconsin-Madison, Environmental Remote Sensing Center in conjunction with seven local, state, and federal agencies to implement automated statewide land cover mapping using satellite remote sensing and geographical information system (GIS) techniques. The basis, progress, and future research needs for this mapping program are presented. The research efforts are directed toward strategies that integrate satellite remote sensing and GIS techniques in the generation of land cover data for multiple users of land cover information. The project objectives are to investigate methodologies that integrate satellite data with other imagery and spatial data resident in emerging GISs in the state for particular program needs, and to develop techniques that can improve automated land cover mapping efficiency and accuracy. 10 refs

Evaluation of satellite-retrieved extreme precipitation using gauge observations

Science.gov (United States)

Lockhoff, M.; Zolina, O.; Simmer, C.; Schulz, J.

2012-04-01

Precipitation extremes have already been intensively studied employing rain gauge datasets. Their main advantage is that they represent a direct measurement with a relatively high temporal coverage. Their main limitation however is their poor spatial coverage and thus a low representativeness in many parts of the world. In contrast, satellites can provide global coverage and there are meanwhile data sets available that are on one hand long enough to be used for extreme value analysis and that have on the other hand the necessary spatial and temporal resolution to capture extremes. However, satellite observations provide only an indirect mean to determine precipitation and there are many potential observational and methodological weaknesses in particular over land surfaces that may constitute doubts concerning their usability for the analysis of precipitation extremes. By comparing basic climatological metrics of precipitation (totals, intensities, number of wet days) as well as respective characteristics of PDFs, absolute and relative extremes of satellite and observational data this paper aims at assessing to which extent satellite products are suitable for analysing extreme precipitation events. In a first step the assessment focuses on Europe taking into consideration various satellite products available, e.g. data sets provided by the Global Precipitation Climatology Project (GPCP). First results indicate that satellite-based estimates do not only represent the monthly averaged precipitation very similar to rain gauge estimates but they also capture the day-to-day occurrence fairly well. Larger differences can be found though when looking at the corresponding intensities.

Web-based spatial analysis with the ILWIS open source GIS software and satellite images from GEONETCast

Science.gov (United States)

Lemmens, R.; Maathuis, B.; Mannaerts, C.; Foerster, T.; Schaeffer, B.; Wytzisk, A.

2009-12-01

This paper involves easy accessible integrated web-based analysis of satellite images with a plug-in based open source software. The paper is targeted to both users and developers of geospatial software. Guided by a use case scenario, we describe the ILWIS software and its toolbox to access satellite images through the GEONETCast broadcasting system. The last two decades have shown a major shift from stand-alone software systems to networked ones, often client/server applications using distributed geo-(web-)services. This allows organisations to combine without much effort their own data with remotely available data and processing functionality. Key to this integrated spatial data analysis is a low-cost access to data from within a user-friendly and flexible software. Web-based open source software solutions are more often a powerful option for developing countries. The Integrated Land and Water Information System (ILWIS) is a PC-based GIS & Remote Sensing software, comprising a complete package of image processing, spatial analysis and digital mapping and was developed as commercial software from the early nineties onwards. Recent project efforts have migrated ILWIS into a modular, plug-in-based open source software, and provide web-service support for OGC-based web mapping and processing. The core objective of the ILWIS Open source project is to provide a maintainable framework for researchers and software developers to implement training components, scientific toolboxes and (web-) services. The latest plug-ins have been developed for multi-criteria decision making, water resources analysis and spatial statistics analysis. The development of this framework is done since 2007 in the context of 52°North, which is an open initiative that advances the development of cutting edge open source geospatial software, using the GPL license. GEONETCast, as part of the emerging Global Earth Observation System of Systems (GEOSS), puts essential environmental data at the

Analysis of Logic Programs Using Regular Tree Languages

DEFF Research Database (Denmark)

Gallagher, John Patrick

2012-01-01

The eld of nite tree automata provides fundamental notations and tools for reasoning about set of terms called regular or recognizable tree languages. We consider two kinds of analysis using regular tree languages, applied to logic programs. The rst approach is to try to discover automatically...... a tree automaton from a logic program, approximating its minimal Herbrand model. In this case the input for the analysis is a program, and the output is a tree automaton. The second approach is to expose or check properties of the program that can be expressed by a given tree automaton. The input...... to the analysis is a program and a tree automaton, and the output is an abstract model of the program. These two contrasting abstract interpretations can be used in a wide range of analysis and verication problems....

Accuracy analysis of indirect georeferencing about TH-1 satellite in Weinan test area

International Nuclear Information System (INIS)

Yunlan, Yang; Haiyan, Hu

2014-01-01

Optical linear scanning sensors can be divided into single-lens sensors and multi-lens sensors according to the number of lenses. In order to build stereo imaging, for single-lens optical systems such as aerial mapping camera ADS40 and ADS80, there are more than two parallel linear arrays placed on the focal plane. And for a multi-lens optical system there is only one linear CCD arrays placed on the center of every focal plan for each lens which is often carried on spacecraft. The difference of design between these two kinds of optical systems leads to the systematic errors, calibration in orbit and approach of data adjustment are different completely. Recent years the domestic space optical sensor systems are focused on multi-lens linear CCD sensor in China, such as TH-1 and ZY-3 both belong to multi-lens optical systems. The parameters influencing the position accuracy of the satellite system which are unknown or unknown precisely even changed after sensor posted launch can be estimated by self-calibration in orbit. So after self-calibration in orbit the accuracy of mapping satellite will often be improved strongly. Comparing to direct georeferencing, the indirect georeferencing as a research approach is introduced to TH-1 satellite in this paper considering the systematic errors completely. Parameters about geometry position systematic error are introduced to the basic co-linearity equations for multi-lenses linear array CCD sensor, and based on the extended model the method of space multi-lens linear array CCD sensor self-calibration bundle adjustment is presented. The test field is in some area of Weinan, Shaanxi province, and the observation data of GCPs and orbit are collected. The extended rigors model is used in bundle adjustment and the accuracy analysis shown that TH-1 has a satisfied metric performance

Spatial and radiometric characterization of multi-spectrum satellite images through multi-fractal analysis

Science.gov (United States)

Alonso, Carmelo; Tarquis, Ana M.; Zúñiga, Ignacio; Benito, Rosa M.

2017-03-01

Several studies have shown that vegetation indexes can be used to estimate root zone soil moisture. Earth surface images, obtained by high-resolution satellites, presently give a lot of information on these indexes, based on the data of several wavelengths. Because of the potential capacity for systematic observations at various scales, remote sensing technology extends the possible data archives from the present time to several decades back. Because of this advantage, enormous efforts have been made by researchers and application specialists to delineate vegetation indexes from local scale to global scale by applying remote sensing imagery. In this work, four band images have been considered, which are involved in these vegetation indexes, and were taken by satellites Ikonos-2 and Landsat-7 of the same geographic location, to study the effect of both spatial (pixel size) and radiometric (number of bits coding the image) resolution on these wavelength bands as well as two vegetation indexes: the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI). In order to do so, a multi-fractal analysis of these multi-spectral images was applied in each of these bands and the two indexes derived. The results showed that spatial resolution has a similar scaling effect in the four bands, but radiometric resolution has a larger influence in blue and green bands than in red and near-infrared bands. The NDVI showed a higher sensitivity to the radiometric resolution than EVI. Both were equally affected by the spatial resolution. From both factors, the spatial resolution has a major impact in the multi-fractal spectrum for all the bands and the vegetation indexes. This information should be taken in to account when vegetation indexes based on different satellite sensors are obtained.

Analysis of BeiDou Satellite Measurements with Code Multipath and Geometry-Free Ionosphere-Free Combinations

Directory of Open Access Journals (Sweden)

Qile Zhao

2016-01-01

Full Text Available Using GNSS observable from some stations in the Asia-Pacific area, the carrier-to-noise ratio (CNR and multipath combinations of BeiDou Navigation Satellite System (BDS, as well as their variations with time and/or elevation were investigated and compared with those of GPS and Galileo. Provided the same elevation, the CNR of B1 observables is the lowest among the three BDS frequencies, while B3 is the highest. The code multipath combinations of BDS inclined geosynchronous orbit (IGSO and medium Earth orbit (MEO satellites are remarkably correlated with elevation, and the systematic “V” shape trends could be eliminated through between-station-differencing or modeling correction. Daily periodicity was found in the geometry-free ionosphere-free (GFIF combinations of both BDS geostationary Earth orbit (GEO and IGSO satellites. The variation range of carrier phase GFIF combinations of GEO satellites is −2.0 to 2.0 cm. The periodicity of carrier phase GFIF combination could be significantly mitigated through between-station differencing. Carrier phase GFIF combinations of BDS GEO and IGSO satellites might also contain delays related to satellites. Cross-correlation suggests that the GFIF combinations’ time series of some GEO satellites might vary according to their relative geometries with the sun.

Analysis of BeiDou Satellite Measurements with Code Multipath and Geometry-Free Ionosphere-Free Combinations.

Science.gov (United States)

Zhao, Qile; Wang, Guangxing; Liu, Zhizhao; Hu, Zhigang; Dai, Zhiqiang; Liu, Jingnan

2016-01-20

Using GNSS observable from some stations in the Asia-Pacific area, the carrier-to-noise ratio (CNR) and multipath combinations of BeiDou Navigation Satellite System (BDS), as well as their variations with time and/or elevation were investigated and compared with those of GPS and Galileo. Provided the same elevation, the CNR of B1 observables is the lowest among the three BDS frequencies, while B3 is the highest. The code multipath combinations of BDS inclined geosynchronous orbit (IGSO) and medium Earth orbit (MEO) satellites are remarkably correlated with elevation, and the systematic "V" shape trends could be eliminated through between-station-differencing or modeling correction. Daily periodicity was found in the geometry-free ionosphere-free (GFIF) combinations of both BDS geostationary Earth orbit (GEO) and IGSO satellites. The variation range of carrier phase GFIF combinations of GEO satellites is -2.0 to 2.0 cm. The periodicity of carrier phase GFIF combination could be significantly mitigated through between-station differencing. Carrier phase GFIF combinations of BDS GEO and IGSO satellites might also contain delays related to satellites. Cross-correlation suggests that the GFIF combinations' time series of some GEO satellites might vary according to their relative geometries with the sun.

Optimizing the Attitude Control of Small Satellite Constellations for Rapid Response Imaging

Science.gov (United States)

Nag, S.; Li, A.

2016-12-01

Distributed Space Missions (DSMs) such as formation flight and constellations, are being recognized as important solutions to increase measurement samples over space and time. Given the increasingly accurate attitude control systems emerging in the commercial market, small spacecraft now have the ability to slew and point within few minutes of notice. In spite of hardware development in CubeSats at the payload (e.g. NASA InVEST) and subsystems (e.g. Blue Canyon Technologies), software development for tradespace analysis in constellation design (e.g. Goddard's TAT-C), planning and scheduling development in single spacecraft (e.g. GEO-CAPE) and aerial flight path optimizations for UAVs (e.g. NASA Sensor Web), there is a gap in open-source, open-access software tools for planning and scheduling distributed satellite operations in terms of pointing and observing targets. This paper will demonstrate results from a tool being developed for scheduling pointing operations of narrow field-of-view (FOV) sensors over mission lifetime to maximize metrics such as global coverage and revisit statistics. Past research has shown the need for at least fourteen satellites to cover the Earth globally everyday using a LandSat-like sensor. Increasing the FOV three times reduces the need to four satellites, however adds image distortion and BRDF complexities to the observed reflectance. If narrow FOV sensors on a small satellite constellation were commanded using robust algorithms to slew their sensor dynamically, they would be able to coordinately cover the global landmass much faster without compensating for spatial resolution or BRDF effects. Our algorithm to optimize constellation satellite pointing is based on a dynamic programming approach under the constraints of orbital mechanics and existing attitude control systems for small satellites. As a case study for our algorithm, we minimize the time required to cover the 17000 Landsat images with maximum signal to noise ratio fall

Pointer Analysis for JavaScript Programming Tools

DEFF Research Database (Denmark)

Feldthaus, Asger

Tools that can assist the programmer with tasks, such as, refactoring or code navigation, have proven popular for Java, C#, and other programming languages. JavaScript is a widely used programming language, and its users could likewise benefit from such tools, but the dynamic nature of the language...... is an obstacle for the development of these. Because of this, tools for JavaScript have long remained ineffective compared to those for many other programming languages. Static pointer analysis can provide a foundation for more powerful tools, although the design of this analysis is itself a complicated endeavor....... In this work, we explore techniques for performing pointer analysis of JavaScript programs, and we find novel applications of these techniques. In particular, we demonstrate how these can be used for code navigation, automatic refactoring, semi-automatic refactoring of incomplete programs, and checking of type...

Space Access for Small Satellites on the K-1

Science.gov (United States)

Faktor, L.

Affordable access to space remains a major obstacle to realizing the increasing potential of small satellites systems. On a per kilogram basis, small launch vehicles are simply too expensive for the budgets of many small satellite programs. Opportunities for rideshare with larger payloads on larger launch vehicles are still rare, given the complications associated with coordinating delivery schedules and deployment orbits. Existing contractual mechanisms are also often inadequate to facilitate the launch of multiple payload customers on the same flight. Kistler Aerospace Corporation is committed to lowering the price and enhancing the availability of space access for small satellite programs through the fully-reusable K-1 launch vehicle. Kistler has been working with a number of entities, including Astrium Ltd., AeroAstro, and NASA, to develop innovative approaches to small satellite missions. The K-1 has been selected by NASA as a Flight Demonstration Vehicle for the Space Launch Initiative. NASA has purchased the flight results during the first four K-1 launches on the performance of 13 advanced launch vehicle technologies embedded in the K-1 vehicle. On K-1 flights #2-#4, opportunities exist for small satellites to rideshare to low-earth orbit for a low-launch price. Kistler's flight demonstration contract with NASA also includes options to fly Add-on Technology Experiment flights. Opportunities exist for rideshare payloads on these flights as well. Both commercial and government customers may take advantage of the rideshare pricing. Kistler is investigating the feasibility of flying dedicated, multiple small payload missions. Such a mission would launch multiple small payloads from a single customer or small payloads from different customers. The orbit would be selected to be compatible with the requirements of as many small payload customers as possible, and make use of reusable hardware, standard interfaces (such as the existing MPAS) and verification plans

EPPUR SI MUOVE: POSITIONAL AND KINEMATIC CORRELATIONS OF SATELLITE PAIRS IN THE LOW Z UNIVERSE

International Nuclear Information System (INIS)

Ibata, Rodrigo A.; Famaey, Benoit; Martin, Nicolas; Lewis, Geraint F.; Ibata, Neil G.

2015-01-01

We have recently shown that pairs of satellite galaxies located diametrically opposite to each other around their host possess predominantly anti-correlated velocities. This is consistent with a scenario in which ≳50% of satellite galaxies belong to kinematically coherent rotating planar structures. Here we extend this analysis, examining satellites of giant galaxies drawn from an SDSS photometric redshift catalog. We find that there is a ∼17% overabundance (>3σ significance) of candidate satellites at positions diametrically opposite to a spectroscopically confirmed satellite. We show that ΛCDM cosmological simulations do not possess this property when contamination is included. After subtracting contamination, we find ∼2 times more satellites diametrically opposed to a spectroscopically confirmed satellite than at 90° from it, at projected distances ranging from 100 to 150 kpc from the host. This independent analysis thus strongly supports our previous results on anti-correlated velocities. We also find that those satellite pairs with anti-correlated velocities have a strong preference (∼3:1) to align with the major axis of the host whereas those with correlated velocities display the opposite behavior. We finally show that repeating a similar analysis to Ibata et al. with same-side satellites is generally hard to interpret, but is not inconsistent with our previous results when strong quality cuts are applied on the sample. This addresses all of the concerns recently raised by Cautun et al., who did not uncover any flaw in our previous analysis, but may simply have hinted at the physical extent of planar satellite structures by pointing out that the anti-correlation signal weakens at radii >150 kpc. All these unexpected positional and kinematic correlations strongly suggest that a substantial fraction of satellite galaxies are causally linked in their formation and evolution

EPPUR SI MUOVE: POSITIONAL AND KINEMATIC CORRELATIONS OF SATELLITE PAIRS IN THE LOW Z UNIVERSE

Energy Technology Data Exchange (ETDEWEB)

Ibata, Rodrigo A.; Famaey, Benoit; Martin, Nicolas [Observatoire astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l’Université, F-67000 Strasbourg (France); Lewis, Geraint F. [Sydney Institute of Astronomy, School of Physics A28, University of Sydney, NSW 2006 (Australia); Ibata, Neil G., E-mail: rodrigo.ibata@astro.unistra.fr [Trinity College, Trinity Street, Cambridge, CB2 1TQ (United Kingdom)

2015-05-20

We have recently shown that pairs of satellite galaxies located diametrically opposite to each other around their host possess predominantly anti-correlated velocities. This is consistent with a scenario in which ≳50% of satellite galaxies belong to kinematically coherent rotating planar structures. Here we extend this analysis, examining satellites of giant galaxies drawn from an SDSS photometric redshift catalog. We find that there is a ∼17% overabundance (>3σ significance) of candidate satellites at positions diametrically opposite to a spectroscopically confirmed satellite. We show that ΛCDM cosmological simulations do not possess this property when contamination is included. After subtracting contamination, we find ∼2 times more satellites diametrically opposed to a spectroscopically confirmed satellite than at 90° from it, at projected distances ranging from 100 to 150 kpc from the host. This independent analysis thus strongly supports our previous results on anti-correlated velocities. We also find that those satellite pairs with anti-correlated velocities have a strong preference (∼3:1) to align with the major axis of the host whereas those with correlated velocities display the opposite behavior. We finally show that repeating a similar analysis to Ibata et al. with same-side satellites is generally hard to interpret, but is not inconsistent with our previous results when strong quality cuts are applied on the sample. This addresses all of the concerns recently raised by Cautun et al., who did not uncover any flaw in our previous analysis, but may simply have hinted at the physical extent of planar satellite structures by pointing out that the anti-correlation signal weakens at radii >150 kpc. All these unexpected positional and kinematic correlations strongly suggest that a substantial fraction of satellite galaxies are causally linked in their formation and evolution.

Thermal radiation analysis for small satellites with single-node model using techniques of equivalent linearization

International Nuclear Information System (INIS)

Anh, N.D.; Hieu, N.N.; Chung, P.N.; Anh, N.T.

2016-01-01

Highlights: • Linearization criteria are presented for a single-node model of satellite thermal. • A nonlinear algebraic system for linearization coefficients is obtained. • The temperature evolutions obtained from different methods are explored. • The temperature mean and amplitudes versus the heat capacity are discussed. • The dual criterion approach yields smaller errors than other approximate methods. - Abstract: In this paper, the method of equivalent linearization is extended to the thermal analysis of satellite using both conventional and dual criteria of linearization. These criteria are applied to a differential nonlinear equation of single-node model of the heat transfer of a small satellite in the Low Earth Orbit. A system of nonlinear algebraic equations for linearization coefficients is obtained in the closed form and then solved by the iteration method. The temperature evolution, average values and amplitudes versus the heat capacity obtained by various approaches including Runge–Kutta algorithm, conventional and dual criteria of equivalent linearization, and Grande's approach are compared together. Numerical results reveal that temperature responses obtained from the method of linearization and Grande's approach are quite close to those obtained from the Runge–Kutta method. The dual criterion yields smaller errors than those of the remaining methods when the nonlinearity of the system increases, namely, when the heat capacity varies in the range [1.0, 3.0] × 10 4  J K −1 .

Exploration of mineral resource deposits based on analysis of aerial and satellite image data employing artificial intelligence methods

Science.gov (United States)

Osipov, Gennady

2013-04-01

We propose a solution to the problem of exploration of various mineral resource deposits, determination of their forms / classification of types (oil, gas, minerals, gold, etc.) with the help of satellite photography of the region of interest. Images received from satellite are processed and analyzed to reveal the presence of specific signs of deposits of various minerals. Course of data processing and making forecast can be divided into some stages: Pre-processing of images. Normalization of color and luminosity characteristics, determination of the necessary contrast level and integration of a great number of separate photos into a single map of the region are performed. Construction of semantic map image. Recognition of bitmapped image and allocation of objects and primitives known to system are realized. Intelligent analysis. At this stage acquired information is analyzed with the help of a knowledge base, which contain so-called "attention landscapes" of experts. Used methods of recognition and identification of images: a) combined method of image recognition, b)semantic analysis of posterized images, c) reconstruction of three-dimensional objects from bitmapped images, d)cognitive technology of processing and interpretation of images. This stage is fundamentally new and it distinguishes suggested technology from all others. Automatic registration of allocation of experts` attention - registration of so-called "attention landscape" of experts - is the base of the technology. Landscapes of attention are, essentially, highly effective filters that cut off unnecessary information and emphasize exactly the factors used by an expert for making a decision. The technology based on denoted principles involves the next stages, which are implemented in corresponding program agents. Training mode -> Creation of base of ophthalmologic images (OI) -> Processing and making generalized OI (GOI) -> Mode of recognition and interpretation of unknown images. Training mode

Biodiesel Emissions Analysis Program

Science.gov (United States)

Using existing data, the EPA's biodiesel emissions analysis program sought to quantify the air pollution emission effects of biodiesel for diesel engines that have not been specifically modified to operate on biodiesel.

Dwarf Cosmology with the Stromlo Missing Satellites Survey

Directory of Open Access Journals (Sweden)

Helmut Jerjen

2010-01-01

Sky Survey. The primary objective of the program is to characterise the baryonic and dark matter components of a complete sample of MW satellites in the Southern hemisphere to provide stringent observational constraints for improving our understanding of how the Milky Way formed and what physical processes governed galaxy formation and evolution in general.

Life Cycle Analysis of Dedicated Nano-Launch Technologies

Science.gov (United States)

Zapata, Edgar; McCleskey, Carey (Editor); Martin, John; Lepsch, Roger; Ternani, Tosoc

2014-01-01

Recent technology advancements have enabled the development of small cheap satellites that can perform useful functions in the space environment. Currently, the only low cost option for getting these payloads into orbit is through ride share programs - small satellites awaiting the launch of a larger satellite, and then riding along on the same launcher. As a result, these small satellite customers await primary payload launches and a backlog exists. An alternative option would be dedicated nano-launch systems built and operated to provide more flexible launch services, higher availability, and affordable prices. The potential customer base that would drive requirements or support a business case includes commercial, academia, civil government and defense. Further, NASA technology investments could enable these alternative game changing options. With this context, in 2013 the Game Changing Development (GCD) program funded a NASA team to investigate the feasibility of dedicated nano-satellite launch systems with a recurring cost of less than $2 million per launch for a 5 kg payload to low Earth orbit. The team products would include potential concepts, technologies and factors for enabling the ambitious cost goal, exploring the nature of the goal itself, and informing the GCD program technology investment decision making process. This paper provides an overview of the life cycle analysis effort that was conducted in 2013 by an inter-center NASA team. This effort included the development of reference nano-launch system concepts, developing analysis processes and models, establishing a basis for cost estimates (development, manufacturing and launch) suitable to the scale of the systems, and especially, understanding the relationship of potential game changing technologies to life cycle costs, as well as other factors, such as flights per year.

Satellite myths

Science.gov (United States)

Easton, Roger L.; Hall, David

2008-01-01

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

Launching the First Indian Satellite

Indian Academy of Sciences (India)

long run, this is not bad since it generates self-confidence and self-reliance - which in the final analysis are .... hopes to find some new X-ray sources. The second ... from the state of health of the satellite can be judged. A tracking network gives ...

Spacecraft design project: Low Earth orbit communications satellite

Science.gov (United States)

Moroney, Dave; Lashbrook, Dave; Mckibben, Barry; Gardener, Nigel; Rivers, Thane; Nottingham, Greg; Golden, Bill; Barfield, Bill; Bruening, Joe; Wood, Dave

1991-01-01

This is the final product of the spacecraft design project completed to fulfill the academic requirements of the Spacecraft Design and Integration 2 course (AE-4871) taught at the U.S. Naval Postgraduate School. The Spacecraft Design and Integration 2 course is intended to provide students detailed design experience in selection and design of both satellite system and subsystem components, and their location and integration into a final spacecraft configuration. The design team pursued a design to support a Low Earth Orbiting (LEO) communications system (GLOBALSTAR) currently under development by the Loral Cellular Systems Corporation. Each of the 14 team members was assigned both primary and secondary duties in program management or system design. Hardware selection, spacecraft component design, analysis, and integration were accomplished within the constraints imposed by the 11 week academic schedule and the available design facilities.

Communication satellite applications

Science.gov (United States)

Pelton, Joseph N.

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

Probabilistic Structural Analysis Program

Science.gov (United States)

Pai, Shantaram S.; Chamis, Christos C.; Murthy, Pappu L. N.; Stefko, George L.; Riha, David S.; Thacker, Ben H.; Nagpal, Vinod K.; Mital, Subodh K.

2010-01-01

NASA/NESSUS 6.2c is a general-purpose, probabilistic analysis program that computes probability of failure and probabilistic sensitivity measures of engineered systems. Because NASA/NESSUS uses highly computationally efficient and accurate analysis techniques, probabilistic solutions can be obtained even for extremely large and complex models. Once the probabilistic response is quantified, the results can be used to support risk-informed decisions regarding reliability for safety-critical and one-of-a-kind systems, as well as for maintaining a level of quality while reducing manufacturing costs for larger-quantity products. NASA/NESSUS has been successfully applied to a diverse range of problems in aerospace, gas turbine engines, biomechanics, pipelines, defense, weaponry, and infrastructure. This program combines state-of-the-art probabilistic algorithms with general-purpose structural analysis and lifting methods to compute the probabilistic response and reliability of engineered structures. Uncertainties in load, material properties, geometry, boundary conditions, and initial conditions can be simulated. The structural analysis methods include non-linear finite-element methods, heat-transfer analysis, polymer/ceramic matrix composite analysis, monolithic (conventional metallic) materials life-prediction methodologies, boundary element methods, and user-written subroutines. Several probabilistic algorithms are available such as the advanced mean value method and the adaptive importance sampling method. NASA/NESSUS 6.2c is structured in a modular format with 15 elements.

Tracking System : Suaineadh satellite experiment

OpenAIRE

Brengesjö, Carl; Selin, Martine

2011-01-01

The purpose of this bachelor thesis is to present a tracking system for the Suaineadh satellite experiment. The experiment is a part of the REXUS (Rocket EXperiments for University Students) program and the objective is to deploy a foldable web in space. The assignment of this thesis is to develop a tracking system to find the parts from the Suaineadh experiment that will land on Earth. It is important to find the parts and recover all the data that the experiment performed during the travel ...

The nuclear analysis program at MURR

International Nuclear Information System (INIS)

Glascock, M.D.

1993-01-01

The University of Missouri-Columbia (MU) has continually upgraded research facilities and programs at the MU research reactor (MURR) throughout its 26-yr history. The Nuclear Analysis Program (NAP) area has participated in these upgrades over the years. As one of the largest activation analysis laboratories on a university campus, the activities of the NAP are broadly representative of the diversity of applications for activation analysis and related nuclear science. This paper describes the MURR's NAP and several of the research, education, and service projects in which the laboratory is currently engaged

Program Analysis and Its Relevance for Educational Research

Directory of Open Access Journals (Sweden)

Bernd Käpplinger

2008-01-01

Full Text Available Program analyses are frequently used in research on continuing education. The use of such analyses will be described in this article. Existing data sources, research topics, qualitative, quantitative and mixed methods, will be discussed. Three types of program analysis will be developed. The article ends with a discussion of the advantages and disadvantages of program analysis in contrast to questionnaires. Future developments and challenges will be sketched in the conclusion. Recommendations for the future development of program analysis will be given. URN: urn:nbn:de:0114-fqs0801379

The impact of landsat satellite monitoring on conservation biology.

Science.gov (United States)

Leimgruber, Peter; Christen, Catherine A; Laborderie, Alison

2005-07-01

Landsat 7's recent malfunctioning will result in significant gaps in long-term satellite monitoring of Earth, affecting not only the research of the Earth science community but also conservation users of these data. To determine whether or how important Landsat monitoring is for conservation and natural resource management, we reviewed the Landsat program's history with special emphasis on the development of user groups. We also conducted a bibliographic search to determine the extent to which conservation research has been based on Landsat data. Conservation biologists were not an early user group of Landsat data because a) biologists lacked technical capacity--computers and software--to analyze these data; b) Landsat's 1980s commercialization rendered images too costly for biologists' budgets; and c) the broad-scale disciplines of conservation biology and landscape ecology did not develop until the mid-to-late 1980s. All these conditions had changed by the 1990s and Landsat imagery became an important tool for conservation biology. Satellite monitoring and Landsat continuity are mandated by the Land Remote Sensing Act of 1992. This legislation leaves open commercial options. However, past experiments with commercial operations were neither viable nor economical, and severely reduced the quality of monitoring, archiving and data access for academia and the public. Future satellite monitoring programs are essential for conservation and natural resource management, must provide continuity with Landsat, and should be government operated.

Integrating computer programs for engineering analysis and design

Science.gov (United States)

Wilhite, A. W.; Crisp, V. K.; Johnson, S. C.

1983-01-01

The design of a third-generation system for integrating computer programs for engineering and design has been developed for the Aerospace Vehicle Interactive Design (AVID) system. This system consists of an engineering data management system, program interface software, a user interface, and a geometry system. A relational information system (ARIS) was developed specifically for the computer-aided engineering system. It is used for a repository of design data that are communicated between analysis programs, for a dictionary that describes these design data, for a directory that describes the analysis programs, and for other system functions. A method is described for interfacing independent analysis programs into a loosely-coupled design system. This method emphasizes an interactive extension of analysis techniques and manipulation of design data. Also, integrity mechanisms exist to maintain database correctness for multidisciplinary design tasks by an individual or a team of specialists. Finally, a prototype user interface program has been developed to aid in system utilization.

Research on orbit prediction for solar-based calibration proper satellite

Science.gov (United States)

Chen, Xuan; Qi, Wenwen; Xu, Peng

2018-03-01

Utilizing the mathematical model of the orbit mechanics, the orbit prediction is to forecast the space target's orbit information of a certain time based on the orbit of the initial moment. The proper satellite radiometric calibration and calibration orbit prediction process are introduced briefly. On the basis of the research of the calibration space position design method and the radiative transfer model, an orbit prediction method for proper satellite radiometric calibration is proposed to select the appropriate calibration arc for the remote sensor and to predict the orbit information of the proper satellite and the remote sensor. By analyzing the orbit constraint of the proper satellite calibration, the GF-1solar synchronous orbit is chose as the proper satellite orbit in order to simulate the calibration visible durance for different satellites to be calibrated. The results of simulation and analysis provide the basis for the improvement of the radiometric calibration accuracy of the satellite remote sensor, which lays the foundation for the high precision and high frequency radiometric calibration.

Medical image transmission via communication satellite. Evaluation of bone scintigraphy

International Nuclear Information System (INIS)

Suzuki, Hideki; Inoue, Tomio; Endo, Keigo; Shimamoto, Shigeru.

1995-01-01

As compared with terrestrial circuits, the communication satellite possesses superior characteristics such as wide area coverage, broadcasting, high capacity, and robustness to disasters. Utilizing the narrow band channel (64 kbps) of the geostationary satellite JCSAT 1 located at the altitude of 36,000 km above the equator, the authors investigated satellite-relayed medical imagings by video signals, with bone scintigraphy as a model. Each bone scintigraphy was taken by a handy-video camera, digitalized and transmitted from faculty of technology located at 25 kilometers apart from our department. Clear bone scintigraphy was obtained via satellite, as seen on the view box. Eight nuclear physicians evaluated 20 cases of bone scintigraphy. ROC (Receiver Operating Characteristic) analysis was performed between the scintigraphies on view box and via satellite by the rating method. The area under the ROC curve was 91.6±2.6% via satellite, and 93.2±2.4% on the view box and there was no significant difference between them. These results suggest that the satellite communication is very useful and effective system to send nuclear imagings to distant institutes. (author)

[Medical image transmission via communication satellite: evaluation of bone scintigraphy].

Science.gov (United States)

Suzuki, H; Inoue, T; Endo, K; Shimamoto, S

1995-10-01

As compared with terrestrial circuits, the communication satellite possesses superior characteristics such as wide area coverage, broadcasting, high capacity, and robustness to disasters. Utilizing the narrow band channel (64 kbps) of the geostationary satellite JCSAT1 located at the altitude of 36,000 km above the equator, the authors investigated satellite-relayed medical images by video signals, with bone scintigraphy as a model. Each bone scintigraphy was taken by a handy-video camera, digitalized and transmitted from faculty of technology located at 25 kilometers apart from our department. Clear bone scintigraphy was obtained via satellite, as seen on the view box. Eight nuclear physicians evaluated 20 cases of bone scintigraphy. ROC (Receiver Operating Characteristic) analysis was performed between the scintigraphies on view box and via satellite by the rating method. The area under the ROC curve was 91.6 +/- 2.6% via satellite, and 93.2 +/- 2.4% on the view box and there was no significant difference between them. These results suggest that the satellite communication is very useful and effective system to send nuclear imagings to distant institutes.

Spatial and temporal changes in household structure locations using high-resolution satellite imagery for population assessment: an analysis in southern Zambia, 2006-2011

Directory of Open Access Journals (Sweden)

Timothy Shields

2016-05-01

Full Text Available Satellite imagery is increasingly available at high spatial resolution and can be used for various purposes in public health research and programme implementation. Comparing a census generated from two satellite images of the same region in rural southern Zambia obtained four and a half years apart identified patterns of household locations and change over time. The length of time that a satellite image-based census is accurate determines its utility. Households were enumerated manually from satellite images obtained in 2006 and 2011 of the same area. Spatial statistics were used to describe clustering, cluster detection, and spatial variation in the location of households. A total of 3821 household locations were enumerated in 2006 and 4256 in 2011, a net change of 435 houses (11.4% increase. Comparison of the images indicated that 971 (25.4% structures were added and 536 (14.0% removed. Further analysis suggested similar household clustering in the two images and no substantial difference in concentration of households across the study area. Cluster detection analysis identified a small area where significantly more household structures were removed than expected; however, the amount of change was of limited practical significance. These findings suggest that random sampling of households for study participation would not induce geographic bias if based on a 4.5-year-old image in this region. Application of spatial statistical methods provides insights into the population distribution changes between two time periods and can be helpful in assessing the accuracy of satellite imagery.

A Comprehensive Plan for the Long-Term Calibration and Validation of Oceanic Biogeochemical Satellite Data

Science.gov (United States)

Hooker, Stanford B.; McClain, Charles R.; Mannino, Antonio

2007-01-01

The primary objective of this planning document is to establish a long-term capability and validating oceanic biogeochemical satellite data. It is a pragmatic solution to a practical problem based primarily o the lessons learned from prior satellite missions. All of the plan's elements are seen to be interdependent, so a horizontal organizational scheme is anticipated wherein the overall leadership comes from the NASA Ocean Biology and Biogeochemistry (OBB) Program Manager and the entire enterprise is split into two components of equal sature: calibration and validation plus satellite data processing. The detailed elements of the activity are based on the basic tasks of the two main components plus the current objectives of the Carbon Cycle and Ecosystems Roadmap. The former is distinguished by an internal core set of responsibilities and the latter is facilitated through an external connecting-core ring of competed or contracted activities. The core elements for the calibration and validation component include a) publish protocols and performance metrics; b) verify uncertainty budgets; c) manage the development and evaluation of instrumentation; and d) coordinate international partnerships. The core elements for the satellite data processing component are e) process and reprocess multisensor data; f) acquire, distribute, and archive data products; and g) implement new data products. Both components have shared responsibilities for initializing and temporally monitoring satellite calibration. Connecting-core elements include (but are not restricted to) atmospheric correction and characterization, standards and traceability, instrument and analysis round robins, field campaigns and vicarious calibration sites, in situ database, bio-optical algorithm (and product) validation, satellite characterization and vicarious calibration, and image processing software. The plan also includes an accountability process, creating a Calibration and Validation Team (to help manage

Space-based solar power conversion and delivery systems study. Volume 2: Engineering analysis of orbital systems

Science.gov (United States)

1976-01-01

Program plans, schedules, and costs are determined for a synchronous orbit-based power generation and relay system. Requirements for the satellite solar power station (SSPS) and the power relay satellite (PRS) are explored. Engineering analysis of large solar arrays, flight mechanics and control, transportation, assembly and maintenance, and microwave transmission are included.

Relative tracking control of constellation satellites considering inter-satellite link

Science.gov (United States)

Fakoor, M.; Amozegary, F.; Bakhtiari, M.; Daneshjou, K.

2017-11-01

In this article, two main issues related to the large-scale relative motion of satellites in the constellation are investigated to establish the Inter Satellite Link (ISL) which means the dynamic and control problems. In the section related to dynamic problems, a detailed and effective analytical solution is initially provided for the problem of satellite relative motion considering perturbations. The direct geometric method utilizing spherical coordinates is employed to achieve this solution. The evaluation of simulation shows that the solution obtained from the geometric method calculates the relative motion of the satellite with high accuracy. Thus, the proposed analytical solution will be applicable and effective. In the section related to control problems, the relative tracking control system between two satellites will be designed in order to establish a communication link between the satellites utilizing analytical solution for relative motion of satellites with respect to the reference trajectory. Sliding mode control approach is employed to develop the relative tracking control system for body to body and payload to payload tracking control. Efficiency of sliding mode control approach is compared with PID and LQR controllers. Two types of payload to payload tracking control considering with and without payload degree of freedom are designed and suitable one for practical ISL applications is introduced. Also, Fuzzy controller is utilized to eliminate the control input in the sliding mode controller.

Combining satellite photographs and raster lidar data for channel connectivity in tidal marshes.

Science.gov (United States)

Li, Zhi; Hodges, Ben

2017-04-01

High resolution airborne lidar is capable of providing topographic detail down to the 1 x 1 m scale or finer over large tidal marshes of a river delta. Such data sets can be challenging to develop and ground-truth due to the inherent complexities of the environment, the relatively small changes in elevation throughout a marsh, and practical difficulties in accessing the variety of flooded, dry, and muddy regions. Standard lidar point-cloud processing techniques (as typically applied in large lidar data collection program) have a tendency to mis-identify narrow channels and water connectivity in a marsh, which makes it difficult to directly use such data for modeling marsh flows. Unfortunately, it is not always practical, or even possible, to access the point cloud and re-analyze the raw lidar data when discrepancies have been found in a raster work product. Faced with this problem in preparing a model of the Trinity River delta (Texas, USA), we developed an approach to integrating analysis of a lidar-based raster with satellite images. Our primary goal was to identify the clear land/water boundaries needed to identify channelization in the available rasterized lidar data. The channel extraction method uses pixelized satellite photographs that are stretched/distorted with image-processing techniques to match identifiable control features in both lidar and photographic data sets. A kmeans clustering algorithm was applied cluster pixels based on their colors, which is effective in separating land and water in a satellite photograph. The clustered image was matched to the lidar data such that the combination shows the channel network. In effect, we are able to use the fact that the satellite photograph is higher resolution than the lidar data, and thus provides connectivity in the clustering at a finer scale. The principal limitation of the method is the where the satellite image and lidar suffer from similar problems For example, vegetation overhanging a narrow

Testing command and control of the satellites in formation flight

Science.gov (United States)

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

2013-10-01

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.

Lsd1 regulates skeletal muscle regeneration and directs the fate of satellite cells.

Science.gov (United States)

Tosic, Milica; Allen, Anita; Willmann, Dominica; Lepper, Christoph; Kim, Johnny; Duteil, Delphine; Schüle, Roland

2018-01-25

Satellite cells are muscle stem cells required for muscle regeneration upon damage. Of note, satellite cells are bipotent and have the capacity to differentiate not only into skeletal myocytes, but also into brown adipocytes. Epigenetic mechanisms regulating fate decision and differentiation of satellite cells during muscle regeneration are not yet fully understood. Here, we show that elevated levels of lysine-specific demethylase 1 (Kdm1a, also known as Lsd1) have a beneficial effect on muscle regeneration and recovery after injury, since Lsd1 directly regulates key myogenic transcription factor genes. Importantly, selective Lsd1 ablation or inhibition in Pax7-positive satellite cells, not only delays muscle regeneration, but changes cell fate towards brown adipocytes. Lsd1 prevents brown adipocyte differentiation of satellite cells by repressing expression of the novel pro-adipogenic transcription factor Glis1. Together, downregulation of Glis1 and upregulation of the muscle-specific transcription program ensure physiological muscle regeneration.

Small-satellite technology and applications; Proceedings of the Meeting, Orlando, FL, Apr. 4, 5, 1991

Science.gov (United States)

Horais, Brian J.

Remote sensing applications and systems, small satellites for sensing missions, and supporting technologies are the broad topics discussed. Particular papers are presented on small satellites for water cycle experiments, low-cost spacecraft buses for remote sensing applications, Webersat (a low-cost imaging satellite), DARPA initiatives in small-satellite technologies, a solid-state magnetic azimuth sensor for small satellites, and thermal analysis of a small expendable tether satellite package. (For individual items see A93-24152 to A93-24175)

Taiwan Space Programs

Science.gov (United States)

Liu, Jann-Yenq

Taiwan space programs consist of FORMOSAT-1, -2, and -3, sounding rockets, and international cooperation. FORMOSAT-1, a low-earth-orbit (LEO) scientific experimental satellite, was launched on January 26, 1999. It circulates with an altitude of 600 km and 35 degree inclination around the Earth every 97 minutes, transmitting collected data to Taiwan's receiving stations approximately six times a day. The major mission of FORMOSAT-1 includes three scientific experiments for measuring the effects of ionospheric plasma and electrodynamics, taking the ocean color image and conducting Ka-band communication experiment. The FORMOSAT- 1 mission was ended by June 15, 2004. FORMOSAT-2, launched on May 21, 2004 onto the Sun-synchronous orbit located at 891 km above ground. The main mission of FORMOSAT-2 is to conduct remote sensing imaging over Taiwan and on terrestrial and oceanic regions of the entire earth. The images captured by FORMOSAT-2 during daytime can be used for land distribution, natural resources research, environmental protection, disaster prevention and rescue work etc. When the satellite travels to the eclipsed zone, it observes natural phenomena of lighting in the upper atmosphere. FORMOSAT-3 is an international collaboration project between Taiwan and the US to develop advanced technology for the real-time monitoring of the global climate. This project is also named Constellation Observing System for Meteorology, Ionosphere and Climate, or FORMOSAT-3/COSMIC for short. Six micro-satellites were launched on 15 April 2007 and eventually placed into six different orbits at 700 800 kilometer above the earth ground. These satellites orbit around the earth to form a LEO constellation that receives signals transmitted by the 24 US GPS satellites. The satellite observation covers the entire global atmosphere and ionosphere, providing over 2,500 global sounding data per day. These data distribute uniformly over the earth's atmosphere. The global climate information

Asymptotic Behavior of an Elastic Satellite with Internal Friction

International Nuclear Information System (INIS)

Haus, E.; Bambusi, D.

2015-01-01

We study the dynamics of an elastic body whose shape and position evolve due to the gravitational forces exerted by a pointlike planet. The main result is that, if all the deformations of the satellite dissipate some energy, then under a suitable nondegeneracy condition there are only three possible outcomes for the dynamics: (i) the orbit of the satellite is unbounded, (ii) the satellite falls on the planet, (iii) the satellite is captured in synchronous resonance i.e. its orbit is asymptotic to a motion in which the barycenter moves on a circular orbit, and the satellite moves rigidly, always showing the same face to the planet. The result is obtained by making use of LaSalle’s invariance principle and by a careful kinematic analysis showing that energy stops dissipating only on synchronous orbits. We also use in quite an extensive way the fact that conservative elastodynamics is a Hamiltonian system invariant under the action of the rotation group

Spatial and temporal variations of albedo and absorbed solar radiation during 2009 - 2016 from IKOR-M satellite program

Science.gov (United States)

Cherviakov, Maksim; Bogdanov, Mikhail; Spiryakhina, Anastasia; Shishkina, Elena; Surkova, Yana; Kulkova, Eugenia

2017-04-01

This report describes Earth's radiation budget IKOR-M satellite program which has been started in Russia. The first satellite "Meteor-M» No 1 of this project was put into orbit in September, 2009. The IKOR-M radiometer is a satellite instrument that measures reflected shortwave radiation (0.3-4.0 µm). It was created in Saratov State University and installed on Russian hydrometeorological satellites "Meteor-M" No 1 and No 2. Radiometer IKOR-M designed for satellite monitoring of the outgoing reflected short-wave radiation, which is one of the components of Earth's radiation budget. Such measurements can be used to derive Earth's surface albedo and absorbed solar radiation. This information also can be used in different models of long-term weather forecasts and in researches of climate change trends (Sklyarov et al., 2016). Satellite "Meteor-M" No 1 and No 2 are heliosynchronous that allows observing from North to South Poles. The basic products of data processing are given in the form of global maps of distribution outgoing short-wave radiation (OSR), albedo and absorbed solar radiation (ASR). Such maps were made for each month during observation period. The IKOR-M product archive is available online at all times. A searchable catalogue of data products is continually updated and users may search and download data products via the Earth radiation balance components research laboratory website (http://www.sgu.ru/structure/geographic/metclim/balans) as soon as they become available. Two series of measurements from two different IKOR-M are available. The first radiometer had worked from October, 2009 to August, 2014 and second - from August, 2014 to the present. Therefore, there is a period when both radiometers work at the same time. Top-of-atmosphere fluxes deduced from the "Meteor-M" No 1 measurements in August, 2014 show very good agreement with the fluxes determined from "Meteor-M" No 2 (Bogdanov et al., 2016). The effect of aging is investigated for first IKOR

Quantitative analysis of geomorphic processes using satellite image data at different scales

Science.gov (United States)

Williams, R. S., Jr.

1985-01-01

When aerial and satellite photographs and images are used in the quantitative analysis of geomorphic processes, either through direct observation of active processes or by analysis of landforms resulting from inferred active or dormant processes, a number of limitations in the use of such data must be considered. Active geomorphic processes work at different scales and rates. Therefore, the capability of imaging an active or dormant process depends primarily on the scale of the process and the spatial-resolution characteristic of the imaging system. Scale is an important factor in recording continuous and discontinuous active geomorphic processes, because what is not recorded will not be considered or even suspected in the analysis of orbital images. If the geomorphic process of landform change caused by the process is less than 200 m in x to y dimension, then it will not be recorded. Although the scale factor is critical, in the recording of discontinuous active geomorphic processes, the repeat interval of orbital-image acquisition of a planetary surface also is a consideration in order to capture a recurring short-lived geomorphic process or to record changes caused by either a continuous or a discontinuous geomorphic process.

Status of CHAP: composite HTGR analysis program

International Nuclear Information System (INIS)

Secker, P.A.; Gilbert, J.S.

1975-12-01

Development of an HTGR accident simulation program is in progress for the prediction of the overall HTGR plant transient response to various initiating events. The status of the digital computer program named CHAP (Composite HTGR Analysis Program) as of June 30, 1975, is given. The philosophy, structure, and capabilities of the CHAP code are discussed. Mathematical descriptions are given for those HTGR components that have been modeled. Component model validation and evaluation using auxiliary analysis codes are also discussed

Muscle Satellite Cell Protein Teneurin‐4 Regulates Differentiation During Muscle Regeneration

Science.gov (United States)

Ishii, Kana; Suzuki, Nobuharu; Mabuchi, Yo; Ito, Naoki; Kikura, Naomi; Fukada, So‐ichiro; Okano, Hideyuki; Takeda, Shin'ichi

2015-01-01

Abstract Satellite cells are maintained in an undifferentiated quiescent state, but during muscle regeneration they acquire an activated stage, and initiate to proliferate and differentiate as myoblasts. The transmembrane protein teneurin‐4 (Ten‐4) is specifically expressed in the quiescent satellite cells; however, its cellular and molecular functions remain unknown. We therefore aimed to elucidate the function of Ten‐4 in muscle satellite cells. In the tibialis anterior (TA) muscle of Ten‐4‐deficient mice, the number and the size of myofibers, as well as the population of satellite cells, were reduced with/without induction of muscle regeneration. Furthermore, we found an accelerated activation of satellite cells in the regenerated Ten‐4‐deficient TA muscle. The cell culture analysis using primary satellite cells showed that Ten‐4 suppressed the progression of myogenic differentiation. Together, our findings revealed that Ten‐4 functions as a crucial player in maintaining the quiescence of muscle satellite cells. Stem Cells 2015;33:3017–3027 PMID:26013034

Single-shell tank retrieval program mission analysis report

Energy Technology Data Exchange (ETDEWEB)

Stokes, W.J.

1998-08-11

This Mission Analysis Report was prepared to provide the foundation for the Single-Shell Tank (SST) Retrieval Program, a new program responsible for waste removal for the SSTS. The SST Retrieval Program is integrated with other Tank Waste Remediation System activities that provide the management, technical, and operations elements associated with planning and execution of SST and SST Farm retrieval and closure. This Mission Analysis Report provides the basis and strategy for developing a program plan for SST retrieval. This Mission Analysis Report responds to a US Department of Energy request for an alternative single-shell tank retrieval approach (Taylor 1997).

Single-shell tank retrieval program mission analysis report

International Nuclear Information System (INIS)

Stokes, W.J.

1998-01-01

This Mission Analysis Report was prepared to provide the foundation for the Single-Shell Tank (SST) Retrieval Program, a new program responsible for waste removal for the SSTS. The SST Retrieval Program is integrated with other Tank Waste Remediation System activities that provide the management, technical, and operations elements associated with planning and execution of SST and SST Farm retrieval and closure. This Mission Analysis Report provides the basis and strategy for developing a program plan for SST retrieval. This Mission Analysis Report responds to a US Department of Energy request for an alternative single-shell tank retrieval approach (Taylor 1997)

Program assessment report, statement of findings. Satellite power systems concept development and evaluation program

Energy Technology Data Exchange (ETDEWEB)

None

1980-11-01

What is known, uncertain, and unknown about the Solar Power Satellite (SPS) concept is stated. The important technical, environmental, and cost goal questions that must be answered prior to making a commitment to the SPS concept are discussed. Although significant technological, environmental and economic questions remain to be answered, the preliminary investigations undertaken in the CDEP do provide a basis for a policy decision on further commitment. Also, areas of research and experimentation required to acquire the knowledge by which a series of informed, time-phased decisions may be made concerning the possibility of the SPS concept playing a major role in the United States' energy future are suggested.

Satellite Application for Disaster Management Information Systems

Science.gov (United States)

Okpanachi, George

Abstract Satellites are becoming increasingly vital to modern day disaster management activities. Earth observation (EO) satellites provide images at various wavelengths that assist rapid-mapping in all phases of the disaster management cycle: mitigation of potential risks in a given area, preparedness for eventual disasters, immediate response to a disaster event, and the recovery/reconstruction efforts follo wing it. Global navigation satellite systems (GNSS) such as the Global Positioning System (GPS) assist all the phases by providing precise location and navigation data, helping manage land and infrastructures, and aiding rescue crews coordinate their search efforts. Effective disaster management is a complex problem, because it involves many parameters, which are usually not easy to measure and even identify: Analysis of current situation, planning, optimum resource management, coordination, controlling and monitoring current activities and making quick and correct decisions are only some of these parameters, whose complete list is very long. Disaster management information systems (DMIS) assist disaster management to analyse the situation better, make decisions and suggest further actions following the emergency plans. This requires not only fast and thorough processing and optimization abilities, but also real-time data provided to the DMIS. The need of DMIS for disaster’s real-time data can be satisfied by small satellites data utilization. Small satellites can provide up-to-data, plus a better media to transfer data. This paper suggests a rationale and a framework for utilization of small Satellite data by DMIS. DMIS should be used ‘’before’’, ‘’during’’ and ‘’after’’ the disasters. Data provided by the Small Satellites are almost crucial in any period of the disasters, because early warning can save lives, and satellite data may help to identify disasters before they occur. The paper also presents’ ‘when’’, �

Handbook of satellite applications

CERN Document Server

Madry, Scott; Camacho-Lara, Sergio

2017-01-01

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.

Satellite image collection optimization

Science.gov (United States)

Martin, William

2002-09-01

Imaging satellite systems represent a high capital cost. Optimizing the collection of images is critical for both satisfying customer orders and building a sustainable satellite operations business. We describe the functions of an operational, multivariable, time dynamic optimization system that maximizes the daily collection of satellite images. A graphical user interface allows the operator to quickly see the results of what if adjustments to an image collection plan. Used for both long range planning and daily collection scheduling of Space Imaging's IKONOS satellite, the satellite control and tasking (SCT) software allows collection commands to be altered up to 10 min before upload to the satellite.

The VLBA-BU-BLAZAR Multi-Wavelength Monitoring Program

Directory of Open Access Journals (Sweden)

Svetlana Jorstad

2016-10-01

Full Text Available We describe a multiwavelength program of monitoring of a sample of bright γ-ray blazars, which the Boston University (BU group has being carrying out since June 2007. The program includes monthly monitoring with the Very Long Baseline Array at 43 GHz, optical photometric and polarimetric observations, construction and analysis of UV and X-ray light curves obtained with the Rossi X-ray Timing Explorer (RXTE and Swift satellites, and construction and analysis of γ-ray light curves based on data provided by the Large Area Telescope of the Fermi Gamma-ray Space Telescope. We present general results about the kinematics of parsec-scale radio jets, as well as the connection between γ-ray outbursts and jet events.

Different AT-rich satellite DNAs in Cucurbita pepo and Cucurbita maxima.

Science.gov (United States)

Ganal, M; Hemleben, V

1986-11-01

The AT-rich highly repeated satellite DNA of Cucurbita pepo (zucchini) and Cucurbita maxima (pumpkin) were cloned and their DNA structure was investigated. DNA sequencing revealed that the repeat length of satellite DNA in Cucurbita pepo is 349-352 base pairs. The percentage of AT-base pairs is about 61%. This satellite is highly conserved in restriction enzyme pattern and DNA sequence; sequence heterogeneity is about 10%. In contrast, the satellite DNA of Cucurbita maxima has a repeat length of 168-169 base pairs. This satellite is also rich in AT-base pairs (64%), existing in at least three different variants as revealed by restriction enzyme analysis and DNA sequencing. The sequence heterogeneity between these variants is about 15%. The two satellite DNAs showed no cross-hybridization to each other and sequence homology is only limited. Nevertheless, we found in the C. pepo genome a high amount of sequences resembling the satellite of C. maxima. In contrast, the satellite repeat of C. pepo is found in the C. maxima DNA only in a few copies. These observations were discussed with respect to satellite DNA evolution and compared to the data received from monocotyledonous species.

Evaluation of Satellite and Model Precipitation Products Over Turkey

Science.gov (United States)

Yilmaz, M. T.; Amjad, M.

2017-12-01

Satellite-based remote sensing, gauge stations, and models are the three major platforms to acquire precipitation dataset. Among them satellites and models have the advantage of retrieving spatially and temporally continuous and consistent datasets, while the uncertainty estimates of these retrievals are often required for many hydrological studies to understand the source and the magnitude of the uncertainty in hydrological response parameters. In this study, satellite and model precipitation data products are validated over various temporal scales (daily, 3-daily, 7-daily, 10-daily and monthly) using in-situ measured precipitation observations from a network of 733 gauges from all over the Turkey. Tropical Rainfall Measurement Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) 3B42 version 7 and European Center of Medium-Range Weather Forecast (ECMWF) model estimates (daily, 3-daily, 7-daily and 10-daily accumulated forecast) are used in this study. Retrievals are evaluated for their mean and standard deviation and their accuracies are evaluated via bias, root mean square error, error standard deviation and correlation coefficient statistics. Intensity vs frequency analysis and some contingency table statistics like percent correct, probability of detection, false alarm ratio and critical success index are determined using daily time-series. Both ECMWF forecasts and TRMM observations, on average, overestimate the precipitation compared to gauge estimates; wet biases are 10.26 mm/month and 8.65 mm/month, respectively for ECMWF and TRMM. RMSE values of ECMWF forecasts and TRMM estimates are 39.69 mm/month and 41.55 mm/month, respectively. Monthly correlations between Gauges-ECMWF, Gauges-TRMM and ECMWF-TRMM are 0.76, 0.73 and 0.81, respectively. The model and the satellite error statistics are further compared against the gauges error statistics based on inverse distance weighting (IWD) analysis. Both the model and satellite data have less IWD errors (14

Maui Space Surveillance System Satellite Categorization Laboratory

Science.gov (United States)

Deiotte, R.; Guyote, M.; Kelecy, T.; Hall, D.; Africano, J.; Kervin, P.

The MSSS satellite categorization laboratory is a fusion of robotics and digital imaging processes that aims to decompose satellite photometric characteristics and behavior in a controlled setting. By combining a robot, light source and camera to acquire non-resolved images of a model satellite, detailed photometric analyses can be performed to extract relevant information about shape features, elemental makeup, and ultimately attitude and function. Using the laboratory setting a detailed analysis can be done on any type of material or design and the results cataloged in a database that will facilitate object identification by "curve-fitting" individual elements in the basis set to observational data that might otherwise be unidentifiable. Currently the laboratory has created, an ST-Robotics five degree of freedom robotic arm, collimated light source and non-focused Apogee camera have all been integrated into a MATLAB based software package that facilitates automatic data acquisition and analysis. Efforts to date have been aimed at construction of the lab as well as validation and verification of simple geometric objects. Simple tests on spheres, cubes and simple satellites show promising results that could lead to a much better understanding of non-resolvable space object characteristics. This paper presents a description of the laboratory configuration and validation test results with emphasis on the non-resolved photometric characteristics for a variety of object shapes, spin dynamics and orientations. The future vision, utility and benefits of the laboratory to the SSA community as a whole are also discussed.

Tethered Satellite System Contingency Investigation Board

Science.gov (United States)

1992-11-01

The Tethered Satellite System (TSS-1) was launched aboard the Space Shuttle Atlantis (STS-46) on July 31, 1992. During the attempted on-orbit operations, the Tethered Satellite System failed to deploy successfully beyond 256 meters. The satellite was retrieved successfully and was returned on August 6, 1992. The National Aeronautics and Space Administration (NASA) Associate Administrator for Space Flight formed the Tethered Satellite System (TSS-1) Contingency Investigation Board on August 12, 1992. The TSS-1 Contingency Investigation Board was asked to review the anomalies which occurred, to determine the probable cause, and to recommend corrective measures to prevent recurrence. The board was supported by the TSS Systems Working group as identified in MSFC-TSS-11-90, 'Tethered Satellite System (TSS) Contingency Plan'. The board identified five anomalies for investigation: initial failure to retract the U2 umbilical; initial failure to flyaway; unplanned tether deployment stop at 179 meters; unplanned tether deployment stop at 256 meters; and failure to move tether in either direction at 224 meters. Initial observations of the returned flight hardware revealed evidence of mechanical interference by a bolt with the level wind mechanism travel as well as a helical shaped wrap of tether which indicated that the tether had been unwound from the reel beyond the travel by the level wind mechanism. Examination of the detailed mission events from flight data and mission logs related to the initial failure to flyaway and the failure to move in either direction at 224 meters, together with known preflight concerns regarding slack tether, focused the assessment of these anomalies on the upper tether control mechanism. After the second meeting, the board requested the working group to complete and validate a detailed integrated mission sequence to focus the fault tree analysis on a stuck U2 umbilical, level wind mechanical interference, and slack tether in upper tether

Program Analysis Scenarios in Rascal

NARCIS (Netherlands)

M.A. Hills (Mark); P. Klint (Paul); J.J. Vinju (Jurgen); F. Durán

2012-01-01

textabstractRascal is a meta programming language focused on the implementation of domain-specific languages and on the rapid construction of tools for software analysis and software transformation. In this paper we focus on the use of Rascal for software analysis. We illustrate a range of scenarios

Trends in communications satellites

CERN Document Server

Curtin, Denis J

1979-01-01

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