Forest cover of North America in the 1970s mapped using Landsat MSS data

Science.gov (United States)

Feng, M.; Sexton, J. O.; Channan, S.; Townshend, J. R.

2015-12-01

The distribution and changes in Earth's forests impact hydrological, biogeochemical, and energy fluxes, as well as ecosystems' capacity to support biodiversity and human economies. Long-term records of forest cover are needed across a broad range of investigation, including climate and carbon-cycle modeling, hydrological studies, habitat analyzes, biological conservation, and land-use planning. Satellite-based observations enable mapping and monitoring of forests at ecologically and economically relevant resolutions and continental or even global extents. Following early forest-mapping efforts using coarser resolution remote sensing data such as the Advanced Very High Resolution Radiometer (AVHRR) and MODerate-resolution Imaging Spectroradiometer (MODIS), forests have been mapped regionally at developed by the Global Land Cover Facility (GLCF) as reference, we developed an automated approach to detect forests using MSS data by leveraging the multispectral and phenological characteristics of forests observed in MSS time-series. The forest-cover map is produced with layers representing the year of observation, detection of forest-cover change relative to 1990, and the uncertainty of forest-cover and -change layers. The approach has been implemented with open-source libraries to facilitate processing large volumes of Landsat MSS images on high-performance computing machines. As the first result of our global mapping effort, we present the forest cover for North America. More than 25,000 Landsat MSS scenes were processed to provide a 120-meter resolution forest cover for North America, which will be made publicly available on the GLCF website (http://www.landcover.org).

A proposed architecture for a satellite-based mobile communications network - The lowest three layers

Science.gov (United States)

Yan, T. Y.; Naderi, F. M.

1986-01-01

Architecture for a commercial mobile satellite network is proposed. The mobile satellite system (MSS) is composed of a network management center, mobile terminals, base stations, and gateways; the functions of each component are described. The satellite is a 'bent pipe' that performs frequency translations, and it has multiple UHF beams. The development of the MSS design based on the seven-layer open system interconnection model is examined. Consideration is given to the functions of the physical, data link, and network layers and the integrated adaptive mobile access protocol.

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.

The Implementation of Minimum Service Standards (MMS on Public Service for Health Services Sector in Bondowoso, Indonesia

Directory of Open Access Journals (Sweden)

Untung Kuzairi

2018-04-01

Full Text Available One of heatlh policies implemented by the hospital is the minimum service standards (MSS. MSS is a benchmark of hospital service quality in providing services to the public. Talking about health service quality problem, it was found out as the field fact that the achievement of MSS indicator in General Hospital of Dr. H. Koesnadi Bondowoso, Indonesia in 2016 still did not fulfill target of standard hospital service (type B and  minimum service standard (MSS of hospital. This fact shows that the quality of health services in general hospital of  dr. H. Koesnadi Bondowoso is still low. So, this research aims to describe the policy implementation of minimum service standard and to analyze the obstacles in the implementation of MSS policy at general hospital of  dr. H. Koesnadi Bondowoso. So, this research would discuss the policy implementation of minimum service standards by using Edward III concept as a tool to analyze it. This research employed qualitative research with phenomenological approach. The results showed that the implementation of MSS policy of dr. H. Koesnadi Bondowoso general hospital still did not run well. This was due to several factors  such as communication, bureaucratic structure, sources, dispositions (attitude and leadership in sectoral ego control. Sectoral ego can be shaped from educational background of specialist doctors who still adhered seniority and lack of individual role of implementor in building interpersonal communication and conflict management.

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.

Full Service ISDN Satellite (FSIS) network model for advanced ISDN satellite design and experiments

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

The Full Service Integrated Services Digital Network (FSIS) network model for advanced satellite designs describes a model suitable for discrete event simulations. A top down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ACTS and the Interim Service ISDN Satellite (ISIS) perform ISDN protocol analyses and switching decisions in the terrestrial domain, whereas FSIS makes all its analyses and decisions on-board the ISDN satellite.

Mobility management in satellite networks

Science.gov (United States)

Johanson, Gary A.

1995-01-01

This paper addresses the methods used or proposed for use in multi-beam and/or multi-satellite networks designed to provide Mobile Satellite Services (MSS). Specific topics include beam crossover in the North American Mobile Satellite (MSAT) system as well as registration and live call hand-off for a multi-regional geosynchronous (GEO) satellite based system and a global coverage Low Earth Orbiting (LEO) system. In the MSAT system, the individual satellite beams cover very large geographic areas so the need for live call hand-off was not anticipated. This paper discusses the methods used to keep track of the beam location of the users so that incoming call announcements or other messages may be directed to them. Proposed new GEO systems with large numbers of beams will provide much smaller geographic coverage in individual beams and thus the need arises to keep track of the user's location as well as to provide live call hand-off as the user traverses from beam to beam. This situation also occurs in proposed LEO systems where the problems are worsened by the need for satellite to satellite hand-off as well as beam to beam hand-off within a single satellite. The paper discusses methods to accomplish these handoffs and proposes system architectures to address the various hand-off scenarios.

15 CFR 950.8 - Satellite Data Services Division (SDSD).

Science.gov (United States)

2010-01-01

... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Satellite Data Services Division (SDSD... THE ENVIRONMENTAL DATA SERVICE ENVIRONMENTAL DATA AND INFORMATION § 950.8 Satellite Data Services Division (SDSD). The Satellite Data Services Division of the EDIS National Climatic Center provides...

Technical developments in international satellite business services

Science.gov (United States)

Tan, P. P.

At the conception of International Satellite Business Services (ISBS), it was a primary objective to provide flexibility for accommodating a variety of service requirements which might be established by mutual agreement between users. The design guidelines are to ensure that the space segment is efficiently utilized, while other satellite services are protected from interference. Other considerations are related to an acceptable earth segment cost, maximum connectivity in worldwide services, the capability of growth and a reasonably smooth transition into future systems, and the maintenance of high performance objectives. Attention is given to a system overview, the characteristics of satellites for ISBS, and technological developments with some application possibilities for ISBS.

47 CFR 25.225 - Geographic Service Requirements for 17/24 GHz Broadcasting Satellite Service.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Geographic Service Requirements for 17/24 GHz Broadcasting Satellite Service. 25.225 Section 25.225 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.225 Geographic Service...

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

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

The Interim Service Integrated Service Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Development for Advanced Satellite Designs describes the development of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into Time Division Multiple Access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the RS-499 interface for satellite uplink. The same ISTA converts in the opposite direction the RS-499 to U-interface data with a simple switch setting.

Interim Service ISDN Satellite (ISIS) hardware experiment design for advanced ISDN satellite design and experiments

Science.gov (United States)

Pepin, Gerard R.

1992-01-01

The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Design for Advanced Satellite Designs describes the design of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into time division multiple access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the V.35 interface for satellite uplink. The same ISTA converts in the opposite direction the V.35 to U-interface data with a simple switch setting.

Combined Global Navigation Satellite Systems in the Space Service Volume

Science.gov (United States)

Force, Dale A.; Miller, James J.

2013-01-01

Besides providing position, velocity, and timing (PVT) for terrestrial users, the Global Positioning System (GPS) is also being used to provide PVT information for earth orbiting satellites. In 2006, F. H. Bauer, et. al., defined the Space Service Volume in the paper GPS in the Space Service Volume , presented at ION s 19th international Technical Meeting of the Satellite Division, and looked at GPS coverage for orbiting satellites. With GLONASS already operational, and the first satellites of the Galileo and Beidou/COMPASS constellations already in orbit, it is time to look at the use of the new Global Navigation Satellite Systems (GNSS) coming into service to provide PVT information for earth orbiting satellites. This presentation extends GPS in the Space Service Volume by examining the coverage capability of combinations of the new constellations with GPS GPS was first explored as a system for refining the position, velocity, and timing of other spacecraft equipped with GPS receivers in the early eighties. Because of this, a new GPS utility developed beyond the original purpose of providing position, velocity, and timing services for land, maritime, and aerial applications. GPS signals are now received and processed by spacecraft both above and below the GPS constellation, including signals that spill over the limb of the earth. Support of GPS space applications is now part of the system plan for GPS, and support of the Space Service Volume by other GNSS providers has been proposed to the UN International Committee on GNSS (ICG). GPS has been demonstrated to provide decimeter level position accuracy in real-time for satellites in low Earth orbit (centimeter level in non-real-time applications). GPS has been proven useful for satellites in geosynchronous orbit, and also for satellites in highly elliptical orbits. Depending on how many satellites are in view, one can keep time locked to the GNSS standard, and through that to Universal Time as long as at least one

Inter-comparison of state-of-the-art MSS and geoid models in the Arctic Ocean

DEFF Research Database (Denmark)

Skourup, Henriette; Farrell, Sinead; Hendricks, Stefan

in errors in the estimated freeboard heights, especially in areas with a sparse lead distribution in consolidated ice conditions. Additionally these errors can impact ocean geostrophic current estimates and remaining biases in the models may impact longer-term, multi-sensor oceanographic time-series of sea......State-of-the-art Arctic Ocean mean sea surface (MSS) and geoid models are used to support sea ice freeboard estimation from satellite altimeters, and for oceanographic studies. However, errors in a given model in the high frequency domain, e.g. due to unresolved gravity features, can result...

Satellite communications for the next generation telecommunication services and networks

Science.gov (United States)

Chitre, D. M.

1991-01-01

Satellite communications can play an important role in provisioning the next-generation telecommunication services and networks, provided the protocols specifying these services and networks are satellite-compatible and the satellite subnetworks, consisting of earth stations interconnected by the processor and the switch on board the satellite, interwork effectively with the terrestrial networks. The specific parameters and procedures of frame relay and broadband integrated services digital network (B-ISDN) protocols which are impacted by a satellite delay. Congestion and resource management functions for frame relay and B-ISDN are discussed in detail, describing the division of these functions between earth stations and on board the satellite. Specific onboard and ground functions are identified as potential candidates for their implementation via neural network technology.

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)

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.

Sharing possibilities amongst CDMA Mobile Satellite Systems, and impacts of terminal characteristics on sharing

Science.gov (United States)

Bambace, Luís Antonio Waack; Ceballos, Décio Castilho

CDMA Mobile Satellite Systems (CDMA MSS) are able to co-directional, co-frequency and co-coverage sharing, and they are strongly interdependent in case of such a sharing. It is also known that the success of any telecommunication project is the use of the correct media to each task. Operators have a clear sight of such a media adequacy in traditional systems, but not necessarily in the case of Mobile Satellite Systems. This creates a risk that a wrong market objective operator causes trouble to other systems. This paper deals with the sharing alternatives for up to four CDMA MSS operating in the same frequency band, and analysts both: satellite to user downlink and user to satellite uplink. The influence of several items in capacity is here treated. The scope includes: downlink power flux density: code availability; single system internal interference; inter-system interference; diversity schemes: average link impairments, margins; user cooperation; terminal specifications and the dependence of the insulation between RHCP and LHCP with fade.

Ecology and sampling techniques of an understudied subterranean habitat: the Milieu Souterrain Superficiel (MSS).

Science.gov (United States)

Mammola, Stefano; Giachino, Pier Mauro; Piano, Elena; Jones, Alexandra; Barberis, Marcel; Badino, Giovanni; Isaia, Marco

2016-12-01

The term Milieu Souterrain Superficiel (MSS) has been used since the early 1980s in subterranean biology to categorize an array of different hypogean habitats. In general terms, a MSS habitat represents the underground network of empty air-filled voids and cracks developing within multiple layers of rock fragments. Its origins can be diverse and is generally covered by topsoil. The MSS habitat is often connected both with the deep hypogean domain-caves and deep rock cracks-and the superficial soil horizon. A MSS is usually characterized by peculiar microclimatic conditions, and it can harbor specialized hypogean, endogean, and surface-dwelling species. In light of the many interpretations given by different authors, we reviewed 235 papers regarding the MSS in order to provide a state-of-the-art description of these habitats and facilitate their study. We have briefly described the different types of MSS mentioned in the scientific literature (alluvial, bedrock, colluvial, volcanic, and other types) and synthesized the advances in the study of the physical and ecological factors affecting this habitat-i.e., microclimate, energy flows, animal communities, and trophic interactions. We finally described and reviewed the available sampling methods used to investigate MSS fauna.

Satellite Antenna Pointing Procedure Driven by the Ground Service Quality

Science.gov (United States)

Yasui, Yoshitsugu

A satellite antenna alignment technique is proposed to ensure terrestrial service quality for users. The antenna bore sight orientation is calculated directly from measured data acquired from general ground receivers, which intercept the communication radio waves from any position on the earth's surface. The method coordinates the satellite pointing parameters with signal strength at the receivers while considering location-specific geographical and antenna radiation characteristics and control accuracy. The theoretical development and its validity are examined in the course of equation derivation. Actual measured data of an existing satellite at the maneuver was applied to the method, and the capability was demonstrated and verified. With the wide diversity of satellite usage, such as for mobile communications, temporary network deployment or post-launch positioning accommodations, the proposed method provides a direct evaluation of satellite communication performance at the service level, in conjunction with using high frequency spot beam antennas, which are highly susceptible to pointing gain. This can facilitate swift and flexible satellite service planning and deployment for operators.

Two Dimensional Array of Piezoresistive Nanomechanical Membrane-Type Surface Stress Sensor (MSS with Improved Sensitivity

Directory of Open Access Journals (Sweden)

Nico F. de Rooij

2012-11-01

Full Text Available We present a new generation of piezoresistive nanomechanical Membrane-type Surface stress Sensor (MSS chips, which consist of a two dimensional array of MSS on a single chip. The implementation of several optimization techniques in the design and microfabrication improved the piezoresistive sensitivity by 3~4 times compared to the first generation MSS chip, resulting in a sensitivity about ~100 times better than a standard cantilever-type sensor and a few times better than optical read-out methods in terms of experimental signal-to-noise ratio. Since the integrated piezoresistive read-out of the MSS can meet practical requirements, such as compactness and not requiring bulky and expensive peripheral devices, the MSS is a promising transducer for nanomechanical sensing in the rapidly growing application fields in medicine, biology, security, and the environment. Specifically, its system compactness due to the integrated piezoresistive sensing makes the MSS concept attractive for the instruments used in mobile applications. In addition, the MSS can operate in opaque liquids, such as blood, where optical read-out techniques cannot be applied.

47 CFR 25.143 - Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz mobile-satellite...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz mobile-satellite service. 25.143 Section 25.143 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses...

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

Science.gov (United States)

2010-10-01

... SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Safety Watch Requirements and Procedures Distress, Alarm, Urgency and Safety Procedures § 80.333 Stations in the maritime mobile-satellite service. The... 47 Telecommunication 5 2010-10-01 2010-10-01 false Stations in the maritime mobile-satellite...

The Mobile Satellite Services Market.

Science.gov (United States)

Anderson, Samuel

Mobile satellite (MSAT) technology is the basis for a new component of the telecommunications industry capable of providing services to small inexpensive subscriber terminals located almost any place in the world. The market for MSAT space segment capacity (bandwidth and power) is a natural monopoly that can be logically and technically…

Overview of the Anik C satellites and services

Science.gov (United States)

Smart, F. H.

An overview of the important technical characteristics of the Anik C series of Canadian communications satellites is presented. The system was launched as part of the Telesat Communications payload of the Space Shuttle in 1982. Among the services the system will in the near future provide are: a 27 MHz channel bandwidth television service for pay-TV distribution in Canada; two TV channels for hockey broadcasts and a transportable TV system; a heavy-voice route telephone service for five major Canadian cities; and a telephone system for business voice and data communications. Services anticipated for Anik-C satellites later in the decade include a Single Channel Per Carrier (SCPC) voice and data communications system for British Columbia and the Maritime Provinces, and a direct-to-home broadcast service to be sold to television markets in the United States.

Land mobile satellite services in Europe

Science.gov (United States)

Bartholomé, P.; Berretta, G.; Rogard, R.

The demand for land-mobile communications on a Europe-wide basis is an important and pressing problem. The pan-European cellular network now in the planning stage will be slow in coming and it will have its limitations. A regional satellite system for Europe to complement the cellular network is the only practical way to satisfy a specialised market that encompasses a population of several hundred thousand mobiles, including road vehicles, merchant shipping, fishing boats, and trains. The deployment of a regional system would take place in a number of phases, the first being based on a simple payload embarked on a host satellite belonging to a European organisation. Further phases will involve the development of more advanced payloads on dedicated satellites. For the long-term future, the use of satellites in highly inclined orbits is being considered as a means of improving their visibility and hence the service quality.

Leveraging In-Memory Technology to improve the acceptance of MSS - a managers' Perspective

OpenAIRE

Mayer, Jörg H.; Esswein, Markus; Goeken, Matthias; Quick, Reiner

2014-01-01

Management support systems (MSS) help managers to perform their jobs more efficiently. With in-memory technology, a new IT enabler promises to support managers by benefits ranging from reducing time for MSS data entry and analysis to complete new topics of analysis. Hence, the present situation is favorable for an MSS redesign applying in-memory apps. Such apps are field-tested and ready-to-use, but from a business perspective they lack impact. Based on findings from a literature review and r...

Definition of technology development missions for early space station satellite servicing, volume 1

Science.gov (United States)

1983-01-01

The testbed role of an early manned space station in the context of a satellite servicing evolutionary development and flight demonstration technology plan which results in a satellite servicing operational capability is defined. A satellite servicing technology development mission (a set of missions) to be performed on an early manned space station is conceptually defined.

47 CFR 25.213 - Inter-Service coordination requirements for the 1.6/2.4 GHz mobile-satellite service.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Inter-Service coordination requirements for the 1.6/2.4 GHz mobile-satellite service. 25.213 Section 25.213 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.213 Inter...

Servicing communication satellites in geostationary orbit

Science.gov (United States)

Russell, Paul K.; Price, Kent M.

1990-01-01

The econmic benefits of a LEO space station are quantified by identifying alternative operating scenarios utilizing the space station's transportation facilities and assembly and repair facilities. Particular consideration is given to the analysis of the impact of on-orbit assembly and servicing on a typical communications satellite is analyzed. The results of this study show that on-orbit servicing can increase the internal rate of return by as much as 30 percent.

The DTU2010MSS Mean Sea Surface In The Arctic - For And With Cyrosat-2 Data

DEFF Research Database (Denmark)

Andersen, Ole Baltazar; Knudsen, Per

2011-01-01

The new Mean Sea Surface DTU10MSS and associated DTU10MDT is presented and evaluated in the Arctic Ocean for the use with Cryosat-2 data. The DTU10MSS is currently the only available MSS which has true global coverage and hence is suitable for referencing when Cryosat-2 data are used in the Arctic....... The DTU10MSS generally has a vertical accuracy better than 10 cm in most areas of the world confirmed by extensive comparison with GPS leveled tide gauges around Britain and Norway. Finally the first comparisons with Cryosat-2 data are presented. The DTU10MSS is valuable for Cryosat-2 due to its true...

SPOT: How good for geology? A comparison with LANDSAT MSS

Science.gov (United States)

Sesoeren, A.

1986-12-01

Geological interpretation possibilities of SPOT MSS and LANDSAT MSS positive prints enlarged to the same scale were compared, using as a test area part of the Jebel Amour (Algeria). The SPOT imagery offers many advantages, filling the gap between remote sensing from space and aerial photography. The best results by visual interpretation are obtained in combining SPOT for the required details with LANDSAT for the synoptic veiw. Further improvements are expected from the use of SPOT stereo-pairs.

Coincident Retrieval of Ocean Surface Roughness and Salinity Using Airborne and Satellite Microwave Radiometry and Reflectometry Measurements during the Carolina Offshore (Caro) Experiment.

Science.gov (United States)

Burrage, D. M.; Wesson, J. C.; Wang, D. W.; Garrison, J. L.; Zhang, H.

2017-12-01

The launch of the Cyclone Global Navigation Satellite System (CYGNSS) constellation of 8 microsats carrying GPS L-band reflectometers on 15 Dec., 2016, and continued operation of the L-band radiometer on the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite, allow these complementary technologies to coincidentally retrieve Ocean surface roughness (Mean Square Slope, MSS), Surface Wind speed (WSP), and Sea Surface Salinity (SSS). The Carolina Offshore (Caro) airborne experiment was conducted jointly by NRL SSC and Purdue University from 7-11 May, 2017 with the goal of under-flying CYGNSS and SMOS and overflying NOAA buoys, to obtain high-resolution reflectometer and radiometer data for combined retrieval of MSS, SSS and WSP on the continental shelf. Airborne instruments included NRL's Salinity Temperature and Roughness Remote Scanner (STARRS) L-, C- and IR-band radiometer system, and a 4-channel dual-pol L-band (GPS) and S-band (XM radio) reflectometer, built by Purdue University. Flights either crossed NOAA buoys on various headings, or intersected with specular point ground tracks at predicted CYGNSS overpass times. Prevailing winds during Caro were light to moderate (1-8 m/s), so specular returns dominated the reflectometer Delay Doppler Maps (DDMs), and MSS was generally low. In contrast, stronger winds (1-12 m/s) and rougher seas (wave heights 1-5 m) were experienced during the preceding Maine Offshore (Maineo) experiment in March, 2016. Several DDM observables were used to retrieve MSS and WSP, and radiometer brightness temperatures produced Sea Surface Temperature (SST), SSS and also WSP estimates. The complementary relationship of Kirchoff's formula e+r=1, between radiometric emissivity, e, and reflectivity, r, was exploited to seek consistent estimates of MSS, and use it to correct the SSS retrievals for sea surface roughness effects. The relative performance and utility of the various airborne and satellite retrieval algorithms

Inland wetland change detection using aircraft MSS [multispectral scanner] data

International Nuclear Information System (INIS)

Jensen, J.R.; Ramsey, E.W.; Mackey, H.E. Jr.; Sharitz, R.R.; Christensen, E.J.

1986-01-01

Nontidal wetlands in a portion of the Savannah River swamp forest affected by reactor cooling water discharges were mapped using March 31, 1981 and April 29, 1985 high-resolution aircraft multispectral scanner (MSS) data. Due to the inherent distortion in the aircraft MSS data and the complex spectral characteristics of the wetland vegetation, it was necessary to implement multiple techniques in the registration and classification of the MSS imagery of the Pen Branch Delta on each date. In particular, it was necessary to use a piecewise-linear registration process over relatively small regions to perform image-to-image registration. When performing unsupervised classification, an iterative ''cluster busting'' technique was used, which simplified the cluster labeling process. These procedures allowed important wetland vegetation categories to be identified on each date. The multiple-date classification maps were then evaluated using a post-classification comparison technique yielding change classes that were of value in determining the extent of inland wetland change in this region

47 CFR 25.148 - Licensing provisions for the Direct Broadcast Satellite Service.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Licensing provisions for the Direct Broadcast Satellite Service. 25.148 Section 25.148 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25.148...

47 CFR 25.211 - Analog video transmissions in the Fixed-Satellite Services.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Analog video transmissions in the Fixed-Satellite Services. 25.211 Section 25.211 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.211 Analog video transmissions...

Definition of technology development missions for early Space Station satellite servicing. Volume 1: Executive summary

Science.gov (United States)

1984-01-01

The Executive Summary volume 1, includes an overview of both phases of the Definition of Technology Development Missions for Early Space Station Satellite Servicing. The primary purpose of Phase 1 of the Marshall Space Flight Center (MSFC) Satellite Servicing Phase 1 study was to establish requirements for demonstrating the capability of performing satellite servicing activities on a permanently manned Space Station in the early 1990s. The scope of Phase 1 included TDM definition, outlining of servicing objectives, derivation of initial Space Station servicing support requirements, and generation of the associated programmatic schedules and cost. The purpose of phase 2 of the satellite servicing study was to expand and refine the overall understanding of how best to use the manned space station as a test bed for demonstration of satellite servicing capabilities.

Customer premise service study for 30/20 GHz satellite system

Science.gov (United States)

Milton, R. T.; Ross, D. P.; Harcar, A. R.; Freedenberg, P.; Schoen, D.

1983-01-01

Satellite systems in which the space segment operates in the 30/20 GHz frequency band are defined and compared as to their potential for providing various types of communications services to customer premises and the economic and technical feasibility of doing so. Technical tasks performed include: market postulation, definition of the ground segment, definition of the space segment, definition of the integrated satellite system, service costs for satellite systems, sensitivity analysis, and critical technology. Based on an analysis of market data, a sufficiently large market for services is projected so as to make the system economically viable. A large market, and hence a high capacity satellite system, is found to be necessary to minimize service costs, i.e., economy of scale is found to hold. The wide bandwidth expected to be available in the 30/20 GHz band, along with frequency reuse which further increases the effective system bandwidth, makes possible the high capacity system. Extensive ground networking is required in most systems to both connect users into the system and to interconnect Earth stations to provide spatial diversity. Earth station spatial diversity is found to be a cost effective means of compensating the large fading encountered in the 30/20 GHz operating band.

Emerging markets for satellite data communications in the public service

Science.gov (United States)

Potter, J. G.

1978-01-01

The paper discusses some of the current and potential markets for satellite data communications as projected by the Public Service Satellite Consortium (PSSC). Organizations in the public service sector are divided into three categories, depending on their expected benefits and organizational changes due to increased satellite telecommunications use: A - modest institutional adjustments are necessary and significant productivity gains are likely; B - institutional requirements picture is promising, but more information is needed to assess benefits and risk; and C - major institutional adjustments are needed, risks are high but possible benefits are high. These criteria are applied to the U.S. health care system, continuing education, equipment maintenance, libraries, environmental monitoring, and other potential markets. The potential revenues are seen to be significant, but what is needed is a cooperative effort by common carriers and major public service institutions to aggregate the market.

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...

The DTU15 MSS (Mean Sea Surface) and DTU15LAT (Lowest Astronomical Tide) reference surface

DEFF Research Database (Denmark)

Andersen, Ole Baltazar; Stenseng, Lars; Piccioni, Gaia

in the Arctic Ocean for DTU10MSS and DTU13MSS.A new reference surface for off-shore vertical referencing is introduced. This is called the DTU15LAT.The surface is derived from the DTU15MSS and the DTU10 Global ocean tide to give a 19 year Lowest Astronomical Tide referenced to either the Mean sea surface...

Robust method for determining steady state initial values for MSS plant models

International Nuclear Information System (INIS)

Ringham, M.R.; Carlson, J.R.

1987-01-01

Results of an EPRI sponsored project (RP 2504-3 amend i) demonstrated that the methodology embodied in the existing System Performance and Analysis Code (SPANC) can be employed to provide initial values for MSS plant models. An EASY5 version of the TMI plant two loop approximation with primary coolant flow recirculation through a failed pump was selected for demonstration purposes. The project entailed replacing the 1967 ASME steam properties in SPANC with the simplified MSS functions. The MSS component models were then recast into equivalent steady state models compatible with the SPANC executive system. A special input routine was written to modify the MSS data to the SPANC data format. The accuracy of the obtained initial values was approximately four significant figures, sufficient to converge on the EASY5 steady state algorithms. Convergence is relatively insensitive to the initial guess in SPANC and are obtained at a computer cost of approximately two minutes on the UNIVAC 1100/60. Since plant configuration is established by data input in SPANC, it can easily be altered to provide initial values for an MMS simulation of all TMI type plants

Second-generation mobile satellite system. A conceptual design and trade-off study

Science.gov (United States)

Sue, M. K.; Park, Y. H.

1985-01-01

In recent years, interest has grown in the mobile satellite (MSAT) system, a satellite-based communications system capable of providing integrated voice and data services to a large number of users. To explore the potential of a commercial mobile satellite system (MSS) beyond the horizon of the first generation, using technologies of the 1990's and to assist MSAT-X in directing its efforts, a conceptual design has been performed for a second-generation system to be launched around the mid-1990's. The design goal is to maximize the number of satellite channels and/or minimize the overall life-cycle cost, subject to the constraint of utilizing a commercial satellite bus with minimum modifications. To provide an optimal design, a series of trade-offs are performed, including antenna sizing, feed configurations, and interference analysis. Interference is a serious problem for MSAT and often an overlapping feed design is required to reduce interbeam interference. The trade-off studies will show that a simple non-overlapping feed is sufficient for the second-generation system, thus avoiding the need for the complicated beam-forming network that is associated with the overlapping feed designs. In addition, a system that operates at L-band, an alternative frequency band that is being considered by some for possible MSAT applications, is also presented.

75 FR 49871 - Fixed and Mobile Services in the Mobile Satellite Service

Science.gov (United States)

2010-08-16

... Census Bureau data are not yet available for the new category, we will estimate small business prevalence... procedures to transactions involving terrestrial use of the MSS spectrum in the 2 GHz, Big LEO, and L-bands... opportunities for full use of the 2 GHz band for stand-alone terrestrial uses. The Commission requests comment...

LEOPACK The integrated services communications system based on LEO satellites

Science.gov (United States)

Negoda, A.; Bunin, S.; Bushuev, E.; Dranovsky, V.

LEOPACK is yet another LEO satellite project which provides global integrated services for 'business' communications. It utilizes packet rather then circuit switching in both terrestrial and satellite chains as well as cellular approach for frequencies use. Original multiple access protocols and decentralized network control make it possible to organize regionally or logically independent and world-wide networks. Relatively small number of satellites (28) provides virtually global network coverage.

The Satellite Data Thematic Core Service within the EPOS Research Infrastructure

Science.gov (United States)

Manunta, Michele; Casu, Francesco; Zinno, Ivana; De Luca, Claudio; Buonanno, Sabatino; Zeni, Giovanni; Wright, Tim; Hooper, Andy; Diament, Michel; Ostanciaux, Emilie; Mandea, Mioara; Walter, Thomas; Maccaferri, Francesco; Fernandez, Josè; Stramondo, Salvatore; Bignami, Christian; Bally, Philippe; Pinto, Salvatore; Marin, Alessandro; Cuomo, Antonio

2017-04-01

EPOS, the European Plate Observing System, is a long-term plan to facilitate the integrated use of data, data products, software and services, available from distributed Research Infrastructures (RI), for solid Earth science in Europe. Indeed, EPOS integrates a large number of existing European RIs belonging to several fields of the Earth science, from seismology to geodesy, near fault and volcanic observatories as well as anthropogenic hazards. The EPOS vision is that the integration of the existing national and trans-national research infrastructures will increase access and use of the multidisciplinary data recorded by the solid Earth monitoring networks, acquired in laboratory experiments and/or produced by computational simulations. The establishment of EPOS will foster the interoperability of products and services in the Earth science field to a worldwide community of users. Accordingly, the EPOS aim is to integrate the diverse and advanced European Research Infrastructures for solid Earth science, and build on new e-science opportunities to monitor and understand the dynamic and complex solid-Earth System. One of the EPOS Thematic Core Services (TCS), referred to as Satellite Data, aims at developing, implementing and deploying advanced satellite data products and services, mainly based on Copernicus data (namely Sentinel acquisitions), for the Earth science community. This work intends to present the technological enhancements, fostered by EPOS, to deploy effective satellite services in a harmonized and integrated way. In particular, the Satellite Data TCS will deploy five services, EPOSAR, GDM, COMET, 3D-Def and MOD, which are mainly based on the exploitation of SAR data acquired by the Sentinel-1 constellation and designed to provide information on Earth surface displacements. In particular, the planned services will provide both advanced DInSAR products (deformation maps, velocity maps, deformation time series) and value-added measurements (source model

Application of MSS-neutron spin echo spectrometer to pulsed neutron sources

International Nuclear Information System (INIS)

Tasaki, S.; Ebisawa, T.; Hino, M.; Kawai, T.

2001-01-01

A multilayer spin splitter (MSS) is a neutron device that gives phase difference between field-parallel and -antiparallel spin component of a superposing state. Since the phase difference is equivalent to the Larmor precession angle, MSS enables us to construct a new type of neutron spin echo (NSE) spectrometer. The new NSE spectrometer has its properties that 1. since the phase shift is neutron flight path length, the spectrometer can be drastically small, 2. the neutron spin echo time is proportional to the neutron wavelength. (author)

Definition of technology development missions for early space station satellite servicing, volume 2

Science.gov (United States)

1983-01-01

The results of all aspects of the early space station satellite servicing study tasks are presented. These results include identification of servicing tasks (and locations), identification of servicing mission system and detailed objectives, functional/operational requirements analyses of multiple servicing scenarios, assessment of critical servicing technology capabilities and development of an evolutionary capability plan, design and validation of selected servicing technology development missions (TDMs), identification of space station satellite servicing accommodation needs, and the cost and schedule implications of acquiring both required technology capability development and conducting the selected TDMs.

LANDSAT-4 MSS and Thematic Mapper data quality and information content analysis

Science.gov (United States)

Anuta, P.; Bartolucci, L.; Dean, E.; Lozano, F.; Malaret, E.; Mcgillem, C. D.; Valdes, J.; Valenzuela, C.

1984-01-01

LANDSAT-4 thematic mapper (TM) and multispectral scanner (MSS) data were analyzed to obtain information on data quality and information content. Geometric evaluations were performed to test band-to-band registration accuracy. Thematic mapper overall system resolution was evaluated using scene objects which demonstrated sharp high contrast edge responses. Radiometric evaluation included detector relative calibration, effects of resampling, and coherent noise effects. Information content evaluation was carried out using clustering, principal components, transformed divergence separability measure, and supervised classifiers on test data. A detailed spectral class analysis (multispectral classification) was carried out to compare the information content of the MSS and TM for a large number of scene classes. A temperature-mapping experiment was carried out for a cooling pond to test the quality of thermal-band calibration. Overall TM data quality is very good. The MSS data are noisier than previous LANDSAT results.

Individual Global Navigation Satellite Systems in the Space Service Volume

Science.gov (United States)

Force, Dale A.

2015-01-01

Besides providing position, navigation, and timing (PNT) to terrestrial users, GPS is currently used to provide for precision orbit determination, precise time synchronization, real-time spacecraft navigation, and three-axis control of Earth orbiting satellites. With additional Global Navigation Satellite Systems (GNSS) coming into service (GLONASS, Beidou, and Galileo), it will be possible to provide these services by using other GNSS constellations. The paper, "GPS in the Space Service Volume," presented at the ION GNSS 19th International Technical Meeting in 2006 (Ref. 1), defined the Space Service Volume, and analyzed the performance of GPS out to 70,000 km. This paper will report a similar analysis of the performance of each of the additional GNSS and compare them with GPS alone. The Space Service Volume, defined as the volume between 3,000 km altitude and geosynchronous altitude, as compared with the Terrestrial Service Volume between the surface and 3,000 km. In the Terrestrial Service Volume, GNSS performance will be similar to performance on the Earth's surface. The GPS system has established signal requirements for the Space Service Volume. A separate paper presented at the conference covers the use of multiple GNSS in the Space Service Volume.

Airborne MSS data processing for multichannel SWIR sensor

Energy Technology Data Exchange (ETDEWEB)

Urai, Minoru; Yamaguchi, Yasushi

1988-05-17

This paper describes the specification of an airborne multi-channel spectrum scanner (MSS) and data processing. MSS has 13 channels of frequencies in the visible - heat infrared region. The channels 1 - 3 correspond to a visible image, the channels 4, 5 to the absorption bands of iron oxides, the channels 6 - 9 (2.2 (m)m band) to the absorption bands of O-H group and carbonates, and the channels 10 - 13 to absorption bands in the heat infrared region. By the least squares residual (LSR) method, a mineral having an absorption band of 2.2 (m)m was further examined. As a result, the LSR image displayed an orange-colored portion. This portion was identified to correspond to epidote. Silica, which has an absorption band of 8 - 10 (m)m in the heat infrared region, was displayed in blue color. A high frequency resolution sensor has a great potential for discrimination and identification of minerals. (2 figs, 2 tabs, 2 refs)

47 CFR 25.210 - Technical requirements for space stations in the Fixed-Satellite Service.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Technical requirements for space stations in the Fixed-Satellite Service. 25.210 Section 25.210 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.210 Technical...

[On-board medical support system (MSS) of flights of promising aerospace sets (design)].

Science.gov (United States)

Ushakov, I B; Bednenko, V S

2010-01-01

It was suggested as the main compositive fractions MSS to consider the base system of automated evaluation of blood redistribution (BR) in body means of crew members protection and prophylaxis (CMPP) of unfavourable effects of flight factors to organism and also the automated circuit of CMPP' control. The advanced MSS includes 4 original measuring channels for registration of the base physiologic indices (electrocardiogram, venous-arterial pulsegram of neck vessels, reogram of head, earlap vessels pulsegram) the dynamic of which allows to determine with the help of computer the BR-integral parameter. The CMPP automated control circuit unites the separate protecting means in common system and executes the individual selection of regimes and CM PP-composition in accord with, first of all, body reactions manifestation and, secondly, individual physiologic status of spaceman. As CMPP was selected the negative pressure production around lower body part. Approlation of constructed active laboratory engineering mock-up MSS has performed investigations with participation of 29 subjects (Volunteers) under the modeling of hemodynamic shifts, developing in human body in short-term antiorthostatic hypokinesia (-10 degrees), as well as, in combined effect of antiorthostatic hypokinesia (-10 degrees), Coriolis acceleration and optokinetic stimulation. Results of investigations have showed, that the use of advanced MSS gives the indices of operator professional activity on the average of 17-32% under the decrease of hemodynamic stressful.

The determinations of remote sensing satellite data delivery service quality: A positivistic case study in Chinese context

Science.gov (United States)

Jin, Jiahua; Yan, Xiangbin; Tan, Qiaoqiao; Li, Yijun

2014-03-01

With the development of remote sensing technology, remote-sensing satellite has been widely used in many aspects of national construction. Big data with different standards and massive users with different needs, make the satellite data delivery service to be a complex giant system. How to deliver remote-sensing satellite data efficiently and effectively is a big challenge. Based on customer service theory, this paper proposes a hierarchy conceptual model for examining the determinations of remote-sensing satellite data delivery service quality in the Chinese context. Three main dimensions: service expectation, service perception and service environment, and 8 sub-dimensions are included in the model. Large amount of first-hand data on the remote-sensing satellite data delivery service have been obtained through field research, semi-structured questionnaire and focused interview. A positivist case study is conducted to validate and develop the proposed model, as well as to investigate the service status and related influence mechanisms. Findings from the analysis demonstrate the explanatory validity of the model, and provide potentially helpful insights for future practice.

The determinations of remote sensing satellite data delivery service quality: A positivistic case study in Chinese context

International Nuclear Information System (INIS)

Jin, Jiahua; Yan, Xiangbin; Tan, Qiaoqiao; Li, Yijun

2014-01-01

With the development of remote sensing technology, remote-sensing satellite has been widely used in many aspects of national construction. Big data with different standards and massive users with different needs, make the satellite data delivery service to be a complex giant system. How to deliver remote-sensing satellite data efficiently and effectively is a big challenge. Based on customer service theory, this paper proposes a hierarchy conceptual model for examining the determinations of remote-sensing satellite data delivery service quality in the Chinese context. Three main dimensions: service expectation, service perception and service environment, and 8 sub-dimensions are included in the model. Large amount of first-hand data on the remote-sensing satellite data delivery service have been obtained through field research, semi-structured questionnaire and focused interview. A positivist case study is conducted to validate and develop the proposed model, as well as to investigate the service status and related influence mechanisms. Findings from the analysis demonstrate the explanatory validity of the model, and provide potentially helpful insights for future practice

Telecommunications: Issues in Providing Cable and Satellite Television Services

Science.gov (United States)

2002-10-01

This report provides information on (1) whether the availability of cable modem Internet access service appears to be affecting the competitiveness of direct broadcast satellite (DBS) companies in the provision of video services, (2) whether cable prices and DBS penetration rates appear to be affected in areas where the DBS companies offer local broadcast channels, and (3) whether the two individual DBS companies are technologically capable of expanding local broadcast channel services into all 210 television markets in the United States.

47 CFR 25.215 - Technical requirements for space stations in the Direct Broadcast Satellite Service.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Technical requirements for space stations in the Direct Broadcast Satellite Service. 25.215 Section 25.215 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.215...

47 CFR 25.142 - Licensing provisions for the non-voice, non-geostationary mobile-satellite service.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Licensing provisions for the non-voice, non-geostationary mobile-satellite service. 25.142 Section 25.142 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space...

Satellites vs. fiber optics based networks and services - Road map to strategic planning

Science.gov (United States)

Marandi, James H. R.

An overview of a generic telecommunications network and its components is presented, and the current developments in satellite and fiber optics technologies are discussed with an eye on the trends in industry. A baseline model is proposed, and a cost comparison of fiber- vs satellite-based networks is made. A step-by-step 'road map' to the successful strategic planning of telecommunications services and facilities is presented. This road map provides for optimization of the current and future networks and services through effective utilization of both satellites and fiber optics. The road map is then applied to different segments of the telecommunications industry and market place, to show its effectiveness for the strategic planning of executives of three types: (1) those heading telecommunications manufacturing concerns, (2) those leading communication service companies, and (3) managers of telecommunication/MIS departments of major corporations. Future networking issues, such as developments in integrated-services digital network standards and technologies, are addressed.

Satellite switching concepts for European business services in the nineties

Science.gov (United States)

Lombard, D.; Rouffet, D.

A first generation of business communication satellites are now operational or to be launched. Increased demands for communication satellite facilities will develop, if special services, such as videoconferencing, can be provided at a reasonable cost. For such developments, it will be necessary to define a second generation of business communication satellites. The present investigation evaluates briefly the size of the expected European market for 1995. A study is conducted of the payload structure for the required satellite system, and aspects related to link budgets and power consumption are explored. It is found that system dimensioning is determined by the up-link and by technology. Critical factors are related to the output and input multiplexors for the link budget, the switching matrix, and implications for the mass budget. The best trade-off between technological, mass, and link budget limitations is achieved in connection with the employment of a hinged antennas satellite, using an intermediate number of spot beams and associated earth stations of reasonable size.

47 CFR 25.149 - Application requirements for ancillary terrestrial components in the mobile-satellite service...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Application requirements for ancillary terrestrial components in the mobile-satellite service networks operating in the 1.5./1.6 GHz, 1.6/2.4 GHz and 2 GHz mobile-satellite service. 25.149 Section 25.149 Telecommunication FEDERAL COMMUNICATIONS...

Method and associated apparatus for capturing, servicing, and de-orbiting earth satellites using robotics

Science.gov (United States)

Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

2009-01-01

This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

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…

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

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Licensing provisions for the 2.3 GHz satellite digital audio radio service. 25.144 Section 25.144 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25...

76 FR 50425 - Service Rules and Policies for the Broadcasting Satellite Service (BSS)

Science.gov (United States)

2011-08-15

... video-on-demand, to consumers in the United States and promote increased competition among satellite and... innovative services, including video, audio, data, and video-on-demand, to consumers in the United States and... variation is 26.3 km. Thus, the measurement range of 30[deg] from the X axis in the X-Z plane proposed by...

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

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Technical requirements for space stations in the satellite digital audio radio service and associated terrestrial repeaters. 25.214 Section 25.214 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS...

47 CFR 101.85 - Transition of the 18.3-19.3 GHz band from the terrestrial fixed services to the fixed-satellite...

Science.gov (United States)

2010-10-01

... terrestrial fixed services to the fixed-satellite service (FSS). 101.85 Section 101.85 Telecommunication... Transition of the 18.3-19.3 GHz band from the terrestrial fixed services to the fixed-satellite service (FSS...-satellite service (FSS). The rules in this section provide for a transition period during which FSS...

Identification of unique interactions between the flexible linker and the RecA-like domains of DEAD-box helicase Mss116

International Nuclear Information System (INIS)

Zhang, Yuan; Palla, Mirkó; Liao, Jung-Chi; Sun, Andrew

2013-01-01

DEAD-box RNA helicases are ATP-dependent proteins implicated in nearly all aspects of RNA metabolism. The yeast DEAD-box helicase Mss116 is unique in its functions of splicing group I and group II introns and activating mRNA translation, but the structural understanding of why it performs these unique functions remains unclear. Here we used sequence analysis and molecular dynamics simulation to identify residues in the flexible linker specific for yeast Mss116, potentially associated with its unique functions. We first identified residues that are 100% conserved in Mss116 of different species of the Saccharomycetaceae family. The amino acids of these conserved residues were then compared with the amino acids of the corresponding residue positions of other RNA helicases to identify residues that have distinct amino acids from other DEAD-box proteins. Four residues in the flexible linker, i.e. N334, E335, P336 and H339, are conserved and Mss116-specific. Molecular dynamics simulation was conducted for the wild-type Mss116 structure and mutant models to examine mutational effects of the linker on the conformational equilibrium. Relatively short MD simulation runs (within 20 ns) were enough for us to observe mutational effects, suggesting serious structural perturbations by these mutations. The mutation of E335 depletes the interactions between E335 and K95 in domain 1. The interactions between N334/P336 and N496/I497 of domain 2 are also abolished by mutation. Our results suggest that tight interactions between the Mss116-specific flexible linker and the two RecA-like domains may be mechanically required to crimp RNA for the unique RNA processes of yeast Mss116. (paper)

Identification of unique interactions between the flexible linker and the RecA-like domains of DEAD-box helicase Mss116

Science.gov (United States)

Zhang, Yuan; Palla, Mirkó; Sun, Andrew; Liao, Jung-Chi

2013-09-01

DEAD-box RNA helicases are ATP-dependent proteins implicated in nearly all aspects of RNA metabolism. The yeast DEAD-box helicase Mss116 is unique in its functions of splicing group I and group II introns and activating mRNA translation, but the structural understanding of why it performs these unique functions remains unclear. Here we used sequence analysis and molecular dynamics simulation to identify residues in the flexible linker specific for yeast Mss116, potentially associated with its unique functions. We first identified residues that are 100% conserved in Mss116 of different species of the Saccharomycetaceae family. The amino acids of these conserved residues were then compared with the amino acids of the corresponding residue positions of other RNA helicases to identify residues that have distinct amino acids from other DEAD-box proteins. Four residues in the flexible linker, i.e. N334, E335, P336 and H339, are conserved and Mss116-specific. Molecular dynamics simulation was conducted for the wild-type Mss116 structure and mutant models to examine mutational effects of the linker on the conformational equilibrium. Relatively short MD simulation runs (within 20 ns) were enough for us to observe mutational effects, suggesting serious structural perturbations by these mutations. The mutation of E335 depletes the interactions between E335 and K95 in domain 1. The interactions between N334/P336 and N496/I497 of domain 2 are also abolished by mutation. Our results suggest that tight interactions between the Mss116-specific flexible linker and the two RecA-like domains may be mechanically required to crimp RNA for the unique RNA processes of yeast Mss116.

Advanced payload concepts and system architecture for emerging services in Indian National Satellite Systems

Science.gov (United States)

Balasubramanian, E. P.; Rao, N. Prahlad; Sarkar, S.; Singh, D. K.

2008-07-01

Over the past two decades Indian Space Research Organization (ISRO) has developed and operationalized satellites to generate a large capacity of transponders for telecommunication service use in INSAT system. More powerful on-board transmitters are built to usher-in direct-to-home broadcast services. These have transformed the Satcom application scenario in the country. With the proliferation of satellite technology, a shift in the Indian market is witnessed today in terms of demand for new services like Broadband Internet, Interactive Multimedia, etc. While it is imperative to pay attention to market trends, ISRO is also committed towards taking the benefits of technological advancement to all round growth of our population, 70% of which dwell in rural areas. The initiatives already taken in space application related to telemedicine, tele-education and Village Resource Centres are required to be taken to a greater height of efficiency. These targets pose technological challenges to build a large capacity and cost-effective satellite system. This paper addresses advanced payload concepts and system architecture along with the trade-off analysis on design parameters in proposing a new generation satellite system capable of extending the reach of the Indian broadband structure to individual users, educational and medical institutions and enterprises for interactive services. This will be a strategic step in the evolution of INSAT system to employ advanced technology to touch every human face of our population.

47 CFR 25.145 - Licensing conditions for the Fixed-Satellite Service in the 20/30 GHz bands.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Licensing conditions for the Fixed-Satellite Service in the 20/30 GHz bands. 25.145 Section 25.145 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25...

Cassini Mission Sequence Subsystem (MSS)

Science.gov (United States)

Alland, Robert

2011-01-01

This paper describes my work with the Cassini Mission Sequence Subsystem (MSS) team during the summer of 2011. It gives some background on the motivation for this project and describes the expected benefit to the Cassini program. It then introduces the two tasks that I worked on - an automatic system auditing tool and a series of corrections to the Cassini Sequence Generator (SEQ_GEN) - and the specific objectives these tasks were to accomplish. Next, it details the approach I took to meet these objectives and the results of this approach, followed by a discussion of how the outcome of the project compares with my initial expectations. The paper concludes with a summary of my experience working on this project, lists what the next steps are, and acknowledges the help of my Cassini colleagues.

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.

The Development of a Field Services Network for a Satellite-Based Educational Telecommunications Experiment. Satellite Technology Demonstration, Technical Report No. 0333.

Science.gov (United States)

Anderson, Frank; And Others

The Satellite Technology Demonstration (STD) of the Federation of Rocky Mountain States (FRMS) employed a technical delivery system to merge effectively hardware and software, products and services. It also needed a nontechnical component to insure product and service acceptance. Accordingly, the STD's Utilization Component was responsible for…

Determining the rate of forest conversion in Mato Grosso, Brazil, using Landsat MSS and AVHRR data

Science.gov (United States)

Nelson, Ross; Horning, Ned; Stone, Thomas A.

1987-01-01

AVHRR-LAC thermal data and Landsat MSS and TM spectral data were used to estimate the rate of forest clearing in Mato Grosso, Brazil, between 1981 and 1984. The Brazilian state was stratified into forest and nonforest. A list sampling procedure was used in the forest stratum to select Landsat MSS scenes for processing based on estimates of fire activity in the scenes. Fire activity in 1984 was estimated using AVHRR-LAC thermal data. State-wide estimates of forest conversion indicate that between 1981 and 1984, 353,966 ha + or - 77,000 ha (0.4 percent of the state area) were converted per year. No evidence of reforestation was found in this digital sample. The relationship between forest clearing rate (based on MSS-TM analysis) and fire activity (estimated using AVHRR data) was noisy (R-squared = 0.41). The results suggest that AVHRR data may be put to better use as a stratification tool than as a subsidiary variable in list sampling.

Definition of satellite servicing technology development missions for early space stations. Volume 2: Technical

Science.gov (United States)

1983-01-01

Early space station accommodation, build-up of space station manipulator capability, on-orbit spacecraft assembly test and launch, large antenna structure deployment, service/refurbish satellite, and servicing of free-flying materials processing platform are discussed.

Satellite provided customer premise services: A forecast of potential domestic demand through the year 2000. Volume 2: Technical report

Science.gov (United States)

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

1983-08-01

The potential United States domestic telecommunications demand for satellite provided customer premises voice, data and video services through the year 2000 were forecast, 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: development of a forecast of the total domestic telecommunications demand, identification of that portion of the telecommunications demand suitable for transmission by satellite systems, identification of that portion of the satellite market addressable by Computer premises services systems, identification of that portion of the satellite market addressabble by Ka-band CPS system, and 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 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.

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.

Telecommunication service markets through the year 2000 in relation to millimeter wave satellite systems

Science.gov (United States)

Stevenson, S. M.

1979-01-01

NASA is currently conducting a series of millimeter wave satellite system and market studies to develop 30/20 GHz satellite system concepts that have commercial potential for the period 1980-2000. The results of the market studies to-date focusing on the overall demand forecasts and distributions by geographic location, distance, and user category are discussed. Tables are presented indicating baseline market forecast voice and video services, data service category, impacted baseline forecast, and traffic/distance distribution voice services. It is concluded that the total market and system activity will be influential in determining the potential role of millimeter wave systems in the overall transmission needs of the nation, and the amount of the total forecasted traffic suitable for millimeter wave systems.

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.

Transportation Satellite Accounts : A New Way of Measuring Transportation Services in America

Science.gov (United States)

2011-01-01

Transportation Satellite Accounts (TSA), produced by the Bureau of Economic Analysis and the Bureau of Transportation Statistics, provides measures of national transportation output. TSA includes both in-house and for-hire transportation services. Fo...

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.

Satellite Communications for ATM

Science.gov (United States)

Shamma, Mohammed A.

2003-01-01

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

Somatic mutation profiles of MSI and MSS colorectal cancer identified by whole exome next generation sequencing and bioinformatics analysis.

Directory of Open Access Journals (Sweden)

Bernd Timmermann

Full Text Available BACKGROUND: Colorectal cancer (CRC is with approximately 1 million cases the third most common cancer worldwide. Extensive research is ongoing to decipher the underlying genetic patterns with the hope to improve early cancer diagnosis and treatment. In this direction, the recent progress in next generation sequencing technologies has revolutionized the field of cancer genomics. However, one caveat of these studies remains the large amount of genetic variations identified and their interpretation. METHODOLOGY/PRINCIPAL FINDINGS: Here we present the first work on whole exome NGS of primary colon cancers. We performed 454 whole exome pyrosequencing of tumor as well as adjacent not affected normal colonic tissue from microsatellite stable (MSS and microsatellite instable (MSI colon cancer patients and identified more than 50,000 small nucleotide variations for each tissue. According to predictions based on MSS and MSI pathomechanisms we identified eight times more somatic non-synonymous variations in MSI cancers than in MSS and we were able to reproduce the result in four additional CRCs. Our bioinformatics filtering approach narrowed down the rate of most significant mutations to 359 for MSI and 45 for MSS CRCs with predicted altered protein functions. In both CRCs, MSI and MSS, we found somatic mutations in the intracellular kinase domain of bone morphogenetic protein receptor 1A, BMPR1A, a gene where so far germline mutations are associated with juvenile polyposis syndrome, and show that the mutations functionally impair the protein function. CONCLUSIONS/SIGNIFICANCE: We conclude that with deep sequencing of tumor exomes one may be able to predict the microsatellite status of CRC and in addition identify potentially clinically relevant mutations.

The role of the restructured Mobile Remote Service Base System (MBS) in support of Space Station maintenance and servicing

Science.gov (United States)

Darlington, T.; Krukewich, K.

1992-08-01

The critical parameters resulting from the restructuring of Space Station Freedom which necessitated the redesign of the Mobile Remote Service Base System (MBS) are described. These include optimization of robotic attachment locations for access to the Space Station truss-mounted orbital replacement units, transport of logistics carriers to the maintenance sites, minimization of EVA overhead associated with maintenance, self-maintenance of other mobile servicing system (MSS) elements on the MBS, and balancing of station EVA and extravehicular robotics in a complementary fashion to minimize maintenance overhead in general. Consideration is given to the configuration of the resulting MBS, which provides the program with maximum flexibility to utilize the assets of the MSS and optimizes end-to-end maintenance with regard to the use of station resources such as crew time and power. Maintenance and servicing scenarios which are instrumental to the reconfigured MBS as well as the results of improved maintenance capability are presented.

Uma biblioteca de pontos de controle para imagens MSS Landsat

OpenAIRE

Fernando Augusto Mitsuo Ii

1985-01-01

O objetivo deste trabalho e desenvolver um sistema para criacao, manutencao e gerenciamento de uma biblioteca de pontos de controle para imagens MSS Landsat. Um ponto de controle e uma caracteristica fisicamente detectavel numa cena, cuja localizacao geodesica e precisamente conhecida. O uso destes pontos e de fundamental importancia num sistema de correcao geometrica de imagens de satelite. A biblioteca permitira que pontos de controle pertencentes a uma dada cena sejam recuperados de uma ma...

Mobile satellite communications in the 1990's

Science.gov (United States)

Singh, Jai

1992-07-01

The evolution of Inmarsat global services from a single market and single service of the 1980's to all of the key mobile markets and a wide range of new terminals and services in the 1990's is described. An overview of existing mobile satellite services, as well as new services under implementation for introduction in the near and longer term, including a handheld satellite phone (Inmarsat-P), is provided. The initiative taken by Inmarsat in the integration of its global mobile satellite services with global navigation capability derived from GPS (Global Positioning System) and the GLONASS (Russian GPS) navigation satellite systems and the provision of an international civil overlay for GPS/GLONASS integrity and augmentation is highlighted. To complete the overview of the development of mobile satellite services in the 1990's, the known national and regional mobile satellite system plans and the various recent proposals for both orbiting and geostationary satellite systems for proving handheld satellite phone and/or data messaging services are described.

A 10-bit 120-MS/s pipelined ADC with improved switch and layout scaling strategy

International Nuclear Information System (INIS)

Zhou Jia; Xu Lili; Li Fule; Wang Zhihua

2015-01-01

A 10 bit, 120 MS/s two-channel pipelined analog-to digital converter (ADC) is presented. The ADC is featured with improved switch by using the body effect to improve its conduction performance. A scaling down strategy is proposed to get more efficiency in the OTAs layout design. Implemented in a 0.18-μm CMOS technology, the ADC's prototype occupied an area of 2.05 × 1.83 mm 2 . With a sampling rate of 120-MS/s and an input of 4.9 MHz, the ADC achieves a spurious-free-dynamic range of 74.32 dB and signal-to-noise-and-distortion ratio of 55.34 dB, while consuming 220-mW/channel at 3-V supply. (paper)

Onboard autonomous mission re-planning for multi-satellite system

Science.gov (United States)

Zheng, Zixuan; Guo, Jian; Gill, Eberhard

2018-04-01

This paper presents an onboard autonomous mission re-planning system for Multi-Satellites System (MSS) to perform onboard re-planing in disruptive situations. The proposed re-planning system can deal with different potential emergency situations. This paper uses Multi-Objective Hybrid Dynamic Mutation Genetic Algorithm (MO-HDM GA) combined with re-planning techniques as the core algorithm. The Cyclically Re-planning Method (CRM) and the Near Real-time Re-planning Method (NRRM) are developed to meet different mission requirements. Simulations results show that both methods can provide feasible re-planning sequences under unforeseen situations. The comparisons illustrate that using the CRM is average 20% faster than the NRRM on computation time. However, by using the NRRM more raw data can be observed and transmitted than using the CRM within the same period. The usability of this onboard re-planning system is not limited to multi-satellite system. Other mission planning and re-planning problems related to autonomous multiple vehicles with similar demands are also applicable.

Errors of Mean Dynamic Topography and Geostrophic Current Estimates in China's Marginal Seas from GOCE and Satellite Altimetry

DEFF Research Database (Denmark)

Jin, Shuanggen; Feng, Guiping; Andersen, Ole Baltazar

2014-01-01

and geostrophic current estimates from satellite gravimetry and altimetry are investigated and evaluated in China's marginal seas. The cumulative error in MDT from GOCE is reduced from 22.75 to 9.89 cm when compared to the Gravity Recovery and Climate Experiment (GRACE) gravity field model ITG-Grace2010 results......The Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) and satellite altimetry can provide very detailed and accurate estimates of the mean dynamic topography (MDT) and geostrophic currents in China's marginal seas, such as, the newest high-resolution GOCE gravity field model GO......-CONS-GCF-2-TIM-R4 and the new Centre National d'Etudes Spatiales mean sea surface model MSS_CNES_CLS_11 from satellite altimetry. However, errors and uncertainties of MDT and geostrophic current estimates from satellite observations are not generally quantified. In this paper, errors and uncertainties of MDT...

An 8 bit 1 MS/s SAR ADC with 7.72-ENOB

Science.gov (United States)

Duan, Jihai; Zhu, Zhiyong; Deng, Jinli; Xu, Weilin

2017-08-01

This paper presents a low power 8-bit 1 MS/s SAR ADC with 7.72-bit ENOB. Without an op-amp, an improved segmented capacitor DAC is proposed to reduce the capacitance and the chip area. A dynamic latch comparator with output offset voltage storage technology is used to improve the precision. Adding an extra positive feedback in the latch is to increase the speed. What is more, two pairs of CMOS switches are utilized to eliminate the kickback noise introduced by the latch. The proposed SAR ADC was fabricated in SMIC 0.18 {{μ }}{{m}} CMOS technology. The measured results show that this design achieves an SFDR of 61.8 dB and an ENOB of 7.72 bits, and it consumes 67.5 μW with the FOM of 312 fJ/conversion-step at 1 MS/s sample under 1.8 V power supply. Project supported by the National Natural Science Foundation of China (Nos. 61161003, 61264001, 61166004) and the Guangxi Key Laboratory of Precision Navigation Technology and Application Foundation (No. DH201501).

Developing Information Services and Tools to Access and Evaluate Data Quality in Global Satellite-based Precipitation Products

Science.gov (United States)

Liu, Z.; Shie, C. L.; Meyer, D. J.

2017-12-01

Global satellite-based precipitation products have been widely used in research and applications around the world. Compared to ground-based observations, satellite-based measurements provide precipitation data on a global scale, especially in remote continents and over oceans. Over the years, satellite-based precipitation products have evolved from single sensor and single algorithm to multi-sensors and multi-algorithms. As a result, many satellite-based precipitation products have been enhanced such as spatial and temporal coverages. With inclusion of ground-based measurements, biases of satellite-based precipitation products have been significantly reduced. However, data quality issues still exist and can be caused by many factors such as observations, satellite platform anomaly, algorithms, production, calibration, validation, data services, etc. The NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) is home to NASA global precipitation product archives including the Tropical Rainfall Measuring Mission (TRMM), the Global Precipitation Measurement (GPM), as well as other global and regional precipitation products. Precipitation is one of the top downloaded and accessed parameters in the GES DISC data archive. Meanwhile, users want to easily locate and obtain data quality information at regional and global scales to better understand how precipitation products perform and how reliable they are. As data service providers, it is necessary to provide an easy access to data quality information, however, such information normally is not available, and when it is available, it is not in one place and difficult to locate. In this presentation, we will present challenges and activities at the GES DISC to address precipitation data quality issues.

A Methodology for Selection of a Satellite Servicing Architecture. Volume 3. Appendices.

Science.gov (United States)

1985-12-01

model transfers between inclined circu- lar orbits. If OSV time of flight becomes more critical . then a choice between the other two techniques is...ABSTRACT iContinue on ,viverse if necesary and identify by block, number) Title: A METODO ~LOGY FOR SELECION~ OF A SATELLITE SERVICING ARCHITEIR VOLUME

A 100 MS/s 9 bit 0.43 mW SAR ADC with custom capacitor array

Science.gov (United States)

Jingjing, Wang; Zemin, Feng; Rongjin, Xu; Chixiao, Chen; Fan, Ye; Jun, Xu; Junyan, Ren

2016-05-01

A low power 9 bit 100 MS/s successive approximation register analog-to-digital converter (SAR ADC) with custom capacitor array is presented. A brand-new 3-D MOM unit capacitor is used as the basic capacitor cell of this capacitor array. The unit capacitor has a capacitance of 1 fF. Besides, the advanced capacitor array structure and switch mode decrease the power consumption a lot. To verify the effectiveness of this low power design, the 9 bit 100 MS/s SAR ADC is implemented in TSMC IP9M 65 nm LP CMOS technology. The measurement results demonstrate that this design achieves an effective number of bits (ENOB) of 7.4 bit, a signal-to-noise plus distortion ratio (SNDR) of 46.40 dB and a spurious-free dynamic range (SFDR) of 62.31 dB at 100 MS/s with 1 MHz input. The SAR ADC core occupies an area of 0.030 mm2 and consumes 0.43 mW under a supply voltage of 1.2 V. The figure of merit (FOM) of the SAR ADC achieves 23.75 fJ/conv. Project supported by the National High-Tech Research and Development Program of China (No. 2013AA014101).

Global Mobile Satellite Service Interference Analysis for the AeroMACS

Science.gov (United States)

Wilson, Jeffrey D.; Apaza, Rafael D.; Hall, Ward; Phillips, Brent

2013-01-01

The AeroMACS (Aeronautical Mobile Airport Communications System), which is based on the IEEE 802.16-2009 mobile wireless standard, is envisioned as the wireless network which will cover all areas of airport surfaces for next generation air transportation. It is expected to be implemented in the 5091-5150 MHz frequency band which is also occupied by mobile satellite service uplinks. Thus the AeroMACS must be designed to avoid interference with this incumbent service. Simulations using Visualyse software were performed utilizing a global database of 6207 airports. Variations in base station and subscriber antenna distribution and gain pattern were examined. Based on these simulations, recommendations for global airport base station and subscriber antenna power transmission limitations are provided.

A 10MS/s 8-bit charge-redistribution ADC for hybrid pixel applications in 65m CMOS

CERN Document Server

Kishishita, T; Krüger, H; Koch, M; Germic, L; Wermes, N

2013-01-01

The design and measurement results of an 8-bit SAR ADC, based on a charge-redistribution DAC, are presented. This ADC is characterized by superior power efficiency and small area, realized by employing a lateral metal–metal capacitor array and a dynamic two-stage comparator. To avoid the need for a highspeed clock and its associated power consumption, an asynchronous logic was implemented in a logic control cell. A test chip has been developed in a 65 nm CMOS technology, including eight ADC channels with different layout flavors of the capacitor array, a transimpedance amplifier as a signal input structure, a serializer, and a custom-made LVDS driver for data transmission. The integral (INL) and differential (DNL) nonlinearities are measured below 0.5 LSB and 0.8 LSB, respectively, for the best channel operating at a sampling frequency of 10 MS/s. The area occupies 40 μm 70 μm for one ADC channel. The power consumption is estimated as 4 μW at 1 MS/s and 38 μW at 10 MS/s with a supply rail of 1.2 V. Th...

Hybrid Terrestrial-Satellite DVB/IP Infrastructure in Overlay Constellations for Triple-Play Services Access in Rural Areas

Directory of Open Access Journals (Sweden)

E. Pallis

2010-01-01

Full Text Available This paper discusses the convergence of digital broadcasting and Internet technologies, by elaborating on the design, implementation, and performance evaluation of a hybrid terrestrial/satellite networking infrastructure, enabling triple-play services access in rural areas. At local/district level, the paper proposes the exploitation of DVB-T platforms in regenerative configurations for creating terrestrial DVB/IP backhaul between the core backbone (in urban areas and a number of intermediate communication nodes distributed within the DVB-T broadcasting footprint (in rural areas. In this way, triple play services that are available at the core backbone, are transferred via the regenerative DVB-T/IP backhaul to the entire district and can be accessed by rural users via the corresponding intermediate node. On the other hand, at regional/national level, the paper proposes the exploitation of a satellite interactive digital video broadcasting platform (DVB S2/RCS as an overlay network that interconnects the regenerative DVB-T/IP platforms, as well as individual users, and services providers, to each other. Performance of the proposed hybrid terrestrial/satellite networking environment is validated through experimental tests that were conducted under real transmission/reception conditions (for the terrestrial segment and via simulation experiments (for the satellite segment at a prototype network infrastructure.

75 FR 67227 - Relocation Cost Sharing in the Broadcast Auxiliary Service

Science.gov (United States)

2010-11-02

... that parties have several options to resolve disputes that may arise including mediation, arbitration... providing commercial service. However, given that as of December 31, 2008, these MSS operators had assets of... annual revenue of over $15 million once they are able to offer commercial services.\\10\\ Consequently, we...

Odyssey, an optimized personal communications satellite system

Science.gov (United States)

Rusch, Roger J.

Personal communications places severe demands on service providers and transmission facilities. Customers are not satisfied with the current levels of service and want improvements. Among the characteristics that users seek are: lower service rates, hand held convenience, acceptable time delays, ubiquitous service, high availability, reliability, and high quality. The space industry is developing commercial space systems for providing mobile communications to personal telephones. Provision of land mobile satellite service is fundamentally different from the fixed satellite service provided by geostationary satellites. In fixed service, the earth based antennas can depend on a clear path from user to satellite. Mobile users in a terrestrial environment commonly encounter blockage due to vegetation, terrain or buildings. Consequently, high elevation angles are of premium value. TRW studied the issues and concluded that a Medium Earth Orbit constellation is the best solution for Personal Communications Satellite Service. TRW has developed Odyssey, which uses twelve satellites in medium altitude orbit to provide personal communications satellite service. The Odyssey communications system projects a multibeam antenna pattern to the Earth. The attitude control system orients the satellites to ensure constant coverage of land mass and coastal areas. Pointing can be reprogrammed by ground control to ensure optimized coverage of the desired service areas. The payload architecture features non-processing, "bent pipe" transponders and matrix amplifiers to ensure dynamic power delivery to high demand areas. Circuit capacity is 3000 circuits per satellite. Each satellite weighs 1917 kg (4226 pounds) at launch and the solar arrays provide 3126 Watts of power. Satellites are launched in pairs on Ariane, Atlas, or other vehicles. Each satellite is placed in a circular orbit at an altitude of 10,354 km. There are three orbit planes inclined at 55° to the equatorial plane

An 11-bit 200 MS/s subrange SAR ADC with low-cost integrated reference buffer

Science.gov (United States)

He, Xiuju; Gu, Xian; Li, Weitao; Jiang, Hanjun; Li, Fule; Wang, Zhihua

2017-10-01

This paper presents an 11-bit 200 MS/s subrange SAR ADC with an integrated reference buffer in 65 nm CMOS. The proposed ADC employs a 3.5-bit flash ADC for coarse conversion, and a compact timing scheme at the flash/SAR boundary to speed up the conversion. The flash decision is used to control charge compensating for the reference voltage to reduce its input-dependent fluctuation. Measurement results show that the fabricated ADC has achieved significant improvement by applying the reference charge compensation. In addition, the ADC achieves a maximum signal-to-noise-and-distortion ratio of 59.3 dB at 200 MS/s. It consumes 3.91 mW from a 1.2 V supply, including the reference buffer. Project supported by the Zhongxing Telecommunication Equipment Corporation and Beijing Microelectronics Technology Institute.

ATM Quality of Service Tests for Digitized Video Using ATM Over Satellite: Laboratory Tests

Science.gov (United States)

Ivancic, William D.; Brooks, David E.; Frantz, Brian D.

1997-01-01

A digitized video application was used to help determine minimum quality of service parameters for asynchronous transfer mode (ATM) over satellite. For these tests, binomially distributed and other errors were digitally inserted in an intermediate frequency link via a satellite modem and a commercial gaussian noise generator. In this paper, the relation- ship between the ATM cell error and cell loss parameter specifications is discussed with regard to this application. In addition, the video-encoding algorithms, test configurations, and results are presented in detail.

Land Mobile Satellite Service (LMSS): A conceptual system design and identification of the critical technologies. Part 1: Executive summary

Science.gov (United States)

Naderi, F. (Editor)

1982-01-01

A system design for a satellite aided land mobile service is described. The advanced system is based on a geostationary satellite which employs a large UHF reflector to communicate with small user antennas on mobile vehicles. It is shown that the system through multiple beam antennas and frequency reuse provides for radiotelephone and dispatch channels. It is concluded that the system is technologically feasible to provide service to rural and remote regions.

UCM BH MSS 133: catalogación de los once manuscritos encuadernados en este volumen facticio

Directory of Open Access Journals (Sweden)

Durán Barceló, Javier

2012-01-01

Full Text Available En 1878 Villa-Amil y Castro publicó el primer catálogo impreso de los manuscritos procedentes del Colegio de San Ildefonso de la Universidad de Alcalá de Henares. Para su trabajo Villa-Amil dependió estrechamente de las catalogaciones efectuadas antes en 1745 y de nuevo en 1800. Recientemente, Paul Oskar Kristeller ha puesto su atención en los manuscritos humanistas de esta colección; la cual es esencial para el estudio del humanismo en la universidad hispana del Renacimiento temprano. Desde este punto de vista se hace necesaria una nueva catalogación de los manuscritos del Colegio de San Ildefonso. Por ejemplo, el volumen facticio MSS 133 contiene once manuscritos de mediados del siglo XV entre los cuales se conserva el único testimonio de una de las obras latinas de Alfonso de Palencia. El objeto de este trabajo es una descripción bibliográfica más detallada de estos once manuscritos encuadernados en UCM BH MSS 133. In 1878 Villa-Amil y Castro published the first printed catalogue of the manuscript collection of the old Colegio de San Ildefonso at the University of Alcalá de Henares. In his work Villa-Amil followed closely the catalogues produced earlier in 1745 and again in 1800. More recently, Paul Oskar Kristeller has focused his interest on the humanistic manuscripts of this collection, as this library becomes essential in the study of humanism in the hispanic universities during the early Renaissance. From this point of view it is necessary a closer examination to the manuscripts belonging to the old Colegio de San Ildefonso. For example, volume MSS 133 contains eleven manuscritpts from the mid 15th century among them a unique testimony of a Latin composition by Alfonso de Palencia. The object of this paper is a more detailed bibliographical description of these eleven manuscripts in UCM BH MSS 133.

Telecommunication service markets through the year 2000 in relation to millimeter wave satellite systems

Science.gov (United States)

Stevenson, S. M.

1979-01-01

NASA is currently conducting a series of millimeter wave satellite system market studies to develop 30/20 GHz satellite system concepts that have commercial potential. Four contractual efforts were undertaken: two parallel and independent system studies and two parallel and independent market studies. The marketing efforts are focused on forecasting the total domestic demand for long haul telecommunications services for the 1980-2000 period. Work completed to date and reported in this paper include projections of: geographical distribution of traffic; traffic volume as a function of urban area size; and user identification and forecasted demand.

Use of feature extraction techniques for the texture and context information in ERTS imagery. [discrimination of land use categories in Kansas from MSS textural-spectral features

Science.gov (United States)

Haralick, R. M.; Kelly, G. L. (Principal Investigator); Bosley, R. J.

1973-01-01

The author has identified the following significant results. The land use category of subimage regions over Kansas within an MSS image can be identified with an accuracy of about 70% using the textural-spectral features of the multi-images from the four MSS bands.

Land use change detection based on multi-date imagery from different satellite sensor systems

Science.gov (United States)

Stow, Douglas A.; Collins, Doretta; Mckinsey, David

1990-01-01

An empirical study is conducted to assess the accuracy of land use change detection using satellite image data acquired ten years apart by sensors with differing spatial resolutions. The primary goals of the investigation were to (1) compare standard change detection methods applied to image data of varying spatial resolution, (2) assess whether to transform the raster grid of the higher resolution image data to that of the lower resolution raster grid or vice versa in the registration process, (3) determine if Landsat/Thermatic Mapper or SPOT/High Resolution Visible multispectral data provide more accurate detection of land use changes when registered to historical Landsat/MSS data. It is concluded that image ratioing of multisensor, multidate satellite data produced higher change detection accuracies than did principal components analysis, and that it is useful as a land use change enhancement method.

Activities of Canadian Satellite Communications, Inc.

Science.gov (United States)

1992-12-01

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

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

Science.gov (United States)

Johnson, Andrew; Kuglitsch, Rebecca; Bresnahan, Megan

2015-01-01

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

The satellite situation center

International Nuclear Information System (INIS)

Teague, M.J.; Sawyer, D.M.; Vette, J.I.

1982-01-01

Considerations related to the early planning for the International Magnetospheric Study (IMS) took into account the desirability of an establishment of specific entities for generating and disseminating coordination information for both retrospective and predictive periods. The organizations established include the IMS/Satellite Situation Center (IMS/SSC) operated by NASA. The activities of the SSC are related to the preparation of reports on predicted and actually achieved satellite positions, the response to inquiries, the compilation of information on satellite experiments, and the issue of periodic status summaries. Attention is given to high-altitude satellite services, other correlative satellite services, non-IMS activities of the SSC, a summary of the SSC request activity, and post-IMS and future activities

Land Mobile Satellite Service (LMSS): A conceptual system design and identification of the critical technologies: Part 2: Technical report

Science.gov (United States)

Naderi, F. (Editor)

1982-01-01

A conceptual system design for a satellite-aided land mobile service is described. A geostationary satellite which employs a large (55-m) UHF reflector to communicate with small inexpensive user antennas on mobile vehicles is discussed. It is shown that such a satellite system through multiple beam antennas and frequency reuse can provide thousands of radiotelephone and dispatch channels serving hundreds of thousands of users throughout the U.S.

A 10 MS/s 8-bit charge-redistribution ADC for hybrid pixel applications in 65 m CMOS

International Nuclear Information System (INIS)

Kishishita, Tetsuichi; Hemperek, Tomasz; Krüger, Hans; Koch, Manuel; Germic, Leonard; Wermes, Norbert

2013-01-01

The design and measurement results of an 8-bit SAR ADC, based on a charge-redistribution DAC, are presented. This ADC is characterized by superior power efficiency and small area, realized by employing a lateral metal–metal capacitor array and a dynamic two-stage comparator. To avoid the need for a high-speed clock and its associated power consumption, an asynchronous logic was implemented in a logic control cell. A test chip has been developed in a 65 nm CMOS technology, including eight ADC channels with different layout flavors of the capacitor array, a transimpedance amplifier as a signal input structure, a serializer, and a custom-made LVDS driver for data transmission. The integral (INL) and differential (DNL) nonlinearities are measured below 0.5 LSB and 0.8 LSB, respectively, for the best channel operating at a sampling frequency of 10 MS/s. The area occupies 40μm×70μm for one ADC channel. The power consumption is estimated as 4μW at 1 MS/s and 38μW at 10 MS/s with a supply rail of 1.2 V. These excellent performance features and the natural radiation hardness of the design, due to the thin gate oxide thickness of transistors, are very interesting for front-end electronics ICs of future hybrid-pixel detector systems

A 10 MS/s 8-bit charge-redistribution ADC for hybrid pixel applications in 65 m CMOS

Energy Technology Data Exchange (ETDEWEB)

Kishishita, Tetsuichi, E-mail: kisisita@physik.uni-bonn.de; Hemperek, Tomasz; Krüger, Hans; Koch, Manuel; Germic, Leonard; Wermes, Norbert

2013-12-21

The design and measurement results of an 8-bit SAR ADC, based on a charge-redistribution DAC, are presented. This ADC is characterized by superior power efficiency and small area, realized by employing a lateral metal–metal capacitor array and a dynamic two-stage comparator. To avoid the need for a high-speed clock and its associated power consumption, an asynchronous logic was implemented in a logic control cell. A test chip has been developed in a 65 nm CMOS technology, including eight ADC channels with different layout flavors of the capacitor array, a transimpedance amplifier as a signal input structure, a serializer, and a custom-made LVDS driver for data transmission. The integral (INL) and differential (DNL) nonlinearities are measured below 0.5 LSB and 0.8 LSB, respectively, for the best channel operating at a sampling frequency of 10 MS/s. The area occupies 40μm×70μm for one ADC channel. The power consumption is estimated as 4μW at 1 MS/s and 38μW at 10 MS/s with a supply rail of 1.2 V. These excellent performance features and the natural radiation hardness of the design, due to the thin gate oxide thickness of transistors, are very interesting for front-end electronics ICs of future hybrid-pixel detector systems.

Satellite-enabled educational services specification and requirements analysis based on user feedback

OpenAIRE

Tsekeridou, Sofia; Tiropanis, Thanassis; Rorris, Dimitris; Constantinos, Makropoulos; Serif, Tacha; Stergioulas, Lampros

2008-01-01

Advanced tele-education services provision in remote geographically dispersed user communities (such as agriculture and maritime), based on the specific needs and requirements of such communities, implies significant infrastructural and broadband connectivity requirements for rich media, timely and quality-assured content delivery and interactivity. The solution to broadband access anywhere is provided by satellite-enabled communication infrastructures. This paper aims to present such satelli...

ATM Quality of Service Parameters at 45 Mbps Using a Satellite Emulator: Laboratory Measurements

Science.gov (United States)

Ivancic, William D.; Bobinsky, Eric A.

1997-01-01

Results of 45-Mbps DS3 intermediate-frequency loopback measurements of asynchronous transfer mode (ATM) quality of service parameters (cell error ratio and cell loss ratio) are presented. These tests, which were conducted at the NASA Lewis Research Center in support of satellite-ATM interoperability research, represent initial efforts to quantify the minimum parameters for stringent ATM applications, such as MPEG-1 and MPEG-2 video transmission. Portions of these results were originally presented to the International Telecommunications Union's ITU-R Working Party 4B in February 1996 in support of their Draft Preliminary Recommendation on the Transmission of ATM Traffic via Satellite.

A GeoServices Infrastructure for Near-Real-Time Access to Suomi NPP Satellite Data

Science.gov (United States)

Evans, J. D.; Valente, E. G.; Hao, W.; Chettri, S.

2012-12-01

The new Suomi National Polar-orbiting Partnership (NPP) satellite extends NASA's moderate-resolution, multispectral observations with a suite of powerful imagers and sounders to support a broad array of research and applications. However, NPP data products consist of a complex set of data and metadata files in highly specialized formats; which NPP's operational ground segment delivers to users only with several hours' delay. This severely limits their use in critical applications such as weather forecasting, emergency / disaster response, search and rescue, and other activities that require near-real-time access to satellite observations. Alternative approaches, based on distributed Direct Broadcast facilities, can reduce the delay in NPP data delivery from hours to minutes, and can make products more directly usable by practitioners in the field. To assess and fulfill this potential, we are developing a suite of software that couples Direct Broadcast data feeds with a streamlined, scalable processing chain and geospatial Web services, so as to permit many more time-sensitive applications to use NPP data. The resulting geoservices infrastructure links a variety of end-user tools and applications to NPP data from different sources, and to other rapidly-changing geospatial data. By using well-known, standard software interfaces (such as OGC Web Services or OPeNDAP), this infrastructure serves a variety of end-user analysis and visualization tools, giving them access into datasets of arbitrary size and resolution and allowing them to request and receive tailored products on demand. The standards-based approach may also streamline data sharing among independent satellite receiving facilities, thus helping them to interoperate in providing frequent, composite views of continent-scale or global regions. To enable others to build similar or derived systems, the service components we are developing (based in part on the Community Satellite Processing Package (CSPP) from

78 FR 19172 - Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit...

Science.gov (United States)

2013-03-29

... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Parts 2 and 25 [IB Docket No. 12-376; FCC 12-161] Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit Space Stations... the Federal Register of March 8, 2013. The document proposed rules for Earth Stations Aboard Aircraft...

Space Network IP Services (SNIS): An Architecture for Supporting Low Earth Orbiting IP Satellite Missions

Science.gov (United States)

Israel, David J.

2005-01-01

The NASA Space Network (SN) supports a variety of missions using the Tracking and Data Relay Satellite System (TDRSS), which includes ground stations in White Sands, New Mexico and Guam. A Space Network IP Services (SNIS) architecture is being developed to support future users with requirements for end-to-end Internet Protocol (IP) communications. This architecture will support all IP protocols, including Mobile IP, over TDRSS Single Access, Multiple Access, and Demand Access Radio Frequency (RF) links. This paper will describe this architecture and how it can enable Low Earth Orbiting IP satellite missions.

Towards Improved Satellite-In Situ Oceanographic Data Interoperability and Associated Value Added Services at the Podaac

Science.gov (United States)

Tsontos, V. M.; Huang, T.; Holt, B.

2015-12-01

The earth science enterprise increasingly relies on the integration and synthesis of multivariate datasets from diverse observational platforms. NASA's ocean salinity missions, that include Aquarius/SAC-D and the SPURS (Salinity Processes in the Upper Ocean Regional Study) field campaign, illustrate the value of integrated observations in support of studies on ocean circulation, the water cycle, and climate. However, the inherent heterogeneity of resulting data and the disparate, distributed systems that serve them complicates their effective utilization for both earth science research and applications. Key technical interoperability challenges include adherence to metadata and data format standards that are particularly acute for in-situ data and the lack of a unified metadata model facilitating archival and integration of both satellite and oceanographic field datasets. Here we report on efforts at the PO.DAAC, NASA's physical oceanographic data center, to extend our data management and distribution support capabilities for field campaign datasets such as those from SPURS. We also discuss value-added services, based on the integration of satellite and in-situ datasets, which are under development with a particular focus on DOMS. The distributed oceanographic matchup service (DOMS) implements a portable technical infrastructure and associated web services that will be broadly accessible via the PO.DAAC for the dynamic collocation of satellite and in-situ data, hosted by distributed data providers, in support of mission cal/val, science and operational applications.

Design Issues for Traffic Management for the ATM UBR + Service for TCP Over Satellite Networks

Science.gov (United States)

Jain, Raj

1999-01-01

This project was a comprehensive research program for developing techniques for improving the performance of Internet protocols over Asynchronous Transfer Mode (ATM) based satellite networks. Among the service categories provided by ATM networks, the most commonly used category for data traffic is the unspecified bit rate (UBR) service. UBR allows sources to send data into the network without any feedback control. The project resulted in the numerous ATM Forum contributions and papers.

Potential markets for advanced satellite communications

Science.gov (United States)

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

1993-09-01

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

Potential markets for advanced satellite communications

Science.gov (United States)

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

1993-01-01

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

Historia de los MSS BH 133 y 128 de Alfonso de Palencia

Directory of Open Access Journals (Sweden)

Durán Barceló, Javier

2012-07-01

Full Text Available El investigador que inspeccione los volúmenes UCM BH MSS 133 y 128 de Alfonso de Palencia encontrará un buen número de marcas y cotas librarias acumuladas a lo largo de su historia. Como veremos en este trabajo, estas signaturas tienen su correspondencia en los inventarios y catálogos de la biblioteca del Colegio de San Ildefonso desde 1720, 1745, 1800 y 1878. Además, la historia de estos manuscritos se puede rastrear hasta la fundación del Colegio mediante un examen analítico de los primitivos inventarios de la librería ildefonsina incluso más allá del año 1517.The researcher who inspects volumes UCM BH MSS 133 and 128 of Alfonso de Palencia will encounter a great variety of old call numbers and librarian marks accumulated throughout their history. As we will find out in this paper, these call numbers have also a parallel existence in the inventories and catalogues of the Library of the Colegio de San Ildefonso produced since 1720, 1745, 1800 y 1878. But the history of these manuscripts can be also traced back to the foundation of the College, as it is demonstrated by an analytical examination of the earlier Library inventories as far as 1517 and beyond.

Deforestation in Mwanza District, Malawi, from 1981 to 1992 as determined from Landsat MSS imagery

Science.gov (United States)

Andrew T. Hudak; Carol A. Wessman

2000-01-01

Malawi is critically short of fuelwood, the primary energy source for its poverty-stricken populace. Deforestation from 1981 to 1992 in Mwanza District in southern Malawi was assessed using Normalized Difference Vegetation Index (NDVI) values calculated from multitemporal Landsat Multispectral Scanner (MSS) images. A control site, where vegetation change was assumed to...

Sharing the 620-790 MHz band allocated to terrestrial television with an audio-bandwidth social service satellite system

Science.gov (United States)

Smith, E. K.; Reinhart, E. E.

1977-01-01

A study was carried out to identify the optimum uplink and downlink frequencies for audio-bandwidth channels for use by a satellite system distributing social services. The study considered functional-user-need models for five types of social services and identified a general baseline system that is appropriate for most of them. Technical aspects and costs of this system and of the frequency bands that it might use were reviewed, leading to the identification of the 620-790 MHz band as a perferred candidate for both uplink and downlink transmissions for nonmobile applications. The study also led to some ideas as to how to configure the satellite system.

A preliminary study of the feasibility of detecting the floating macrophytes by means of digital processing of MSS/LANDSAT data

Science.gov (United States)

Valeriano, D. D. (Principal Investigator)

1984-01-01

The feasibility of mapping the floating macrophytes (mostly water hyacinth: (Eichornia crassipes) in the Salto Grande reservoir in Americana, SP, by means of digital processing of MSS/LANDSAT data is described. The area occupied by the macrophytes was extracted by exclusion after the merging of two thematic masks representing the area of vegetation free water surface. One of the masks was obtained from a date when the vegetal cover is insignificant, while the other represents a large infestation episode. The utilization of digital processing of MSS/LANDSAT data techniques for the documentation of macrophytes infestation is feasible only when the phenomenon occurs in large areas.

Cyberinfrastructure Initiatives of the Committee on Earth Observation Satellites (CEOS) Working Group on Information Systems and Services (WGISS)

Science.gov (United States)

McDonald, K. R.; Faundeen, J. L.; Petiteville, I.

2005-12-01

The Committee on Earth Observation Satellites (CEOS) was established in 1984 in response to a recommendation from the Economic Summit of Industrialized Nations Working Group on Growth, Technology, and Employment's Panel of Experts on Satellite Remote Sensing. CEOS participants are Members, who are national or international governmental organizations who operate civil spaceborne Earth observation satellites, and Associates who are governmental organizations with civil space programs in development or international scientific or governmental bodies who have an interest in and support CEOS objectives. The primary objective of CEOS is to optimize benefits of satellite Earth observations through cooperation of its participants in mission planning and in development of compatible data products, formats, services, applications and policies. To pursue its objectives, CEOS establishes working groups and associated subgroups that focus on relevant areas of interest. While the structure of CEOS has evolved over its lifetime, today there are three permanent working groups. One is the Working Group on Calibration and Validation that addresses sensor-specific calibration and validation and geophysical parameter validation. A second is the Working Group on Education, Training, and Capacity Building that facilitates activities that enhance international education and training in Earth observation techniques, data analysis, interpretation and applications, with a particular focus on developing countries. The third permanent working group is the Working Group on Information Systems and Services (WGISS). The purpose of WGISS is to promote collaboration in the development of the systems and services based on international standards that manage and supply the Earth observation data and information from participating agencies' missions. WGISS places great emphasis on the use of demonstration projects involving user groups to solve the critical interoperability issues associated with the

A FD/DAMA network architecture for the first generation land mobile satellite services

Science.gov (United States)

Yan, T.-Y.; Wang, C.; Cheng, U.; Dessouky, K.; Rafferty, W.

1989-01-01

A frequency division/demand assigned multiple access (FD/DAMA) network architecture for the first-generation land mobile satellite services is presented. Rationales and technical approaches are described. In this architecture, each mobile subscriber must follow a channel access protocol to make a service request to the network management center before transmission for either open-end or closed-end services. Open-end service requests will be processed on a blocked call cleared basis, while closed-end requests will be processed on a first-come-first-served basis. Two channel access protocols are investigated, namely, a recently proposed multiple channel collision resolution scheme which provides a significantly higher useful throughput, and the traditional slotted Aloha scheme. The number of channels allocated for either open-end or closed-end services can be adaptively changed according to aggregated traffic requests. Both theoretical and simulation results are presented. Theoretical results have been verified by simulation on the JPL network testbed.

Innovative Development and Forecast of BeiDou System

Directory of Open Access Journals (Sweden)

TAN Shusen

2017-10-01

Full Text Available Due to the strong demand for satellite applications and rapid development of new space technology,the cross-integration of space-based radio systems has become a trend.BeiDou system started from two satellites to build China's first generation satellite navigation and positioning system with the features of fast location reporting(RDSSand short message communication(MSSservice.Then BeiDou technology frame combined with RNSS continuous navigation and RDSS location report,was constructed in eight years,and the coverage in Asia-Pacific was completed.Through effective satellite radio frequency compatible design and international coordination,BeiDou system is the first radio satellite system which includes RNSS,RDSS,MSS three major services,approved by International Telecommunication Union(ITUin the world.This paper expounds the development process,technical frame,main features and prospect of BeiDou system with three major services and four key functions,in the concept of innovation and transcendence.

Interworking evolution of mobile satellite and terrestrial networks

Science.gov (United States)

Matyas, R.; Kelleher, P.; Moller, P.; Jones, T.

1993-01-01

There is considerable interest among mobile satellite service providers in interworking with terrestrial networks to provide a universal global network. With such interworking, subscribers may be provided a common set of services such as those planned for the Public Switched Telephone Network (PSTN), the Integrated Services Digital Network (ISDN), and future Intelligent Networks (IN's). This paper first reviews issues in satellite interworking. Next the status and interworking plans of terrestrial mobile communications service providers are examined with early examples of mobile satellite interworking including a discussion of the anticipated evolution towards full interworking between mobile satellite and both fixed and mobile terrestrial networks.

Establishing a Robotic, LEO-to-GEO Satellite Servicing Infrastructure as an Economic Foundation for Exploration

Science.gov (United States)

Horsham, Gary A. P.; Schmidt, George R.; Gilland, James H.

2010-01-01

The strategy for accomplishing civilian exploration goals and objectives is in the process of a fundamental shift towards a potential new approach called Flexible Path. This paper suggests that a government-industry or public-private partnership in the commercial development of low Earth orbit to geostationary orbit (LEO-to-GEO (LTG)) space, following or in parallel with the commercialization of Earth-to-LEO and International Space Station (ISS) operations, could serve as a necessary, logical step that can be incorporated into the flexible path approach. A LTG satellite-servicing infrastructure and architecture concept is discussed within this new strategic context. The concept consists of a space harbor that serves as a transport facility for a fleet of specialized, fully- or semi-autonomous robotic servicing spacecraft. The baseline, conceptual system architecture is composed of a space harbor equipped with specialized servicer spacecraft; a satellite command, communication, and control system; a parts station; a fuel station or depot; and a fuel/parts replenishment transport. The commercial servicer fleet would consist of several types of spacecraft, each designed with specialized robotic manipulation subsystems to provide services such as refueling, upgrade, repair, inspection, relocation, and removal. The space harbor is conceptualized as an ISS-type, octagonal truss structure equipped with radiation tolerant subsystems. This space harbor would be primarily capable of serving as an operational platform for various commercially owned and operated servicer spacecraft positioned and docked symmetrically on four of the eight sides. Several aspects of this concept are discussed, such as: system-level feasibility in terms of ISS-truss-type infrastructure and subsystems emplacement and maintenance between LEO and GEO; infrastructure components assembly in LEO, derived from ISS assembly experience, and transfer to various higher orbital locations; the evolving Earth

A low-voltage low-power 10-bit 200 MS/s pipelined ADC in 90 nm CMOS

NARCIS (Netherlands)

Abdinia, S.; Yavari, M.

2010-01-01

This paper presents a low-power 10-bit 200 MS/s pipelined ADC in a 90 nm CMOS technology with 1 V supply voltage. To decrease the power dissipation efficiently, a new architecture using a combination of two power reduction techniques named double-sampling and opamp-sharing has been used to reduce

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

Science.gov (United States)

1976-01-01

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

Security Concepts for Satellite Links

Science.gov (United States)

Tobehn, C.; Penné, B.; Rathje, R.; Weigl, A.; Gorecki, Ch.; Michalik, H.

2008-08-01

The high costs to develop, launch and maintain a satellite network makes protecting the assets imperative. Attacks may be passive such as eavesdropping on the payload data. More serious threat are active attacks that try to gain control of the satellite, which may lead to the total lost of the satellite asset. To counter these threats, new satellite and ground systems are using cryptographic technologies to provide a range of services: confidentiality, entity & message authentication, and data integrity. Additionally, key management cryptographic services are required to support these services. This paper describes the key points of current satellite control and operations, that are authentication of the access to the satellite TMTC link and encryption of security relevant TM/TC data. For payload data management the key points are multi-user ground station access and high data rates both requiring frequent updates and uploads of keys with the corresponding key management methods. For secure satellite management authentication & key negotiation algorithms as HMAC-RIPEMD160, EC- DSA and EC-DH are used. Encryption of data uses algorithms as IDEA, AES, Triple-DES, or other. A channel coding and encryption unit for payload data provides download data rates up to Nx250 Mbps. The presented concepts are based on our experience and heritage of the security systems for all German MOD satellite projects (SATCOMBw2, SAR-Lupe multi- satellite system and German-French SAR-Lupe-Helios- II systems inter-operability) as well as for further international (KOMPSAT-II Payload data link system) and ESA activities (TMTC security and GMES).

GAUSS Market Analysis for Integrated Satellite Communication and Navigation Location Based services

Science.gov (United States)

Di Fazio, Antonella; Dricot, Fabienne; Tata, Francesco

2003-07-01

The demand for mobile information services coupled with positioning technologies for delivering value- added services that depend on a user's location has rapidly increased during last years. In particular, services and applications related with improved mobility safety and transport efficiency look very attractive.Solutions for location services vary in respect of positioning accuracy and the technical infrastructure required, and the associated investment in terminals and networks. From the analysis of the state-of-the art, it comes that various technologies are currently available on the European market, while mobile industry is gearing up to launch a wide variety of location services like tracking, alarming and locating.Nevertheless, when addressing safety of life as well as security applications, severe hurdles have to be posed in the light of existing technologies. Existing navigation (e.g. GPS) and communication systems are not able to completely satisfy the needs and requirements of safety-of-life-critical applications. As a matter of fact, the GPS system's main weaknesses today is its lack of integrity, which means its inability to warn users of a malfunction in a reasonable time, while the other positioning techniques do not provide satisfactory accuracy as well, and terrestrial communication networks are not capable to cope with stringent requirement in terms of service reliability and coverage.In this context, GAUSS proposes an innovative satellite-based solution using novel technology and effective tools for addressing mobility challenges in a cost efficient manner, improving safety and effectiveness.GAUSS (Galileo And UMTS Synergetic System) is a Research and Technological Development project co- funded by European Commission, within the frame of the 5th IST Programme. The project lasted two years, and it was successfully completed in November 2002. GAUSS key concept is the integration of Satellite Navigation GNSS and UMTS communication technology, to

Definition of technology development missions for early Space Station satellite servicing. Volume 2: Technical

Science.gov (United States)

Cable, D. A.; Diewald, C. A.; Hills, T. C.; Parmentier, T. J.; Spencer, R. A.; Stone, G. E.

1984-01-01

Volume 2 contains the Technical Report of the approach and results of the Phase 2 study. The phase 2 servicing study was initiated in June 1983, and is being reported in this document. The scope of the contract was to: (1) define in detail five selected technology development missions (TDM); (2) conduct a design requirement analysis to refine definitions of satellite servicing requirements at the space station; and (3) develop a technology plan that would identify and schedule prerequisite precursor technology development, associated. STS flight experiments and space station experiments needed to provide onorbit validation of the evolving technology.

Next generation satellite communications networks

Science.gov (United States)

Garland, P. J.; Osborne, F. J.; Streibl, I.

The paper introduces two potential uses for new space hardware to permit enhanced levels of signal handling and switching in satellite communication service for Canada. One application involves increased private-sector services in the Ku band; the second supports new personal/mobile services by employing higher levels of handling and switching in the Ka band. First-generation satellite regeneration and switching experiments involving the NASA/ACTS spacecraft are described, where the Ka band and switching satellite network problems are emphasized. Second-generation satellite development is outlined based on demand trends for more packet-based switching, low-cost earth stations, and closed user groups. A demonstration mission for new Ka- and Ku-band technologies is proposed, including the payload configuration. The half ANIK E payload is shown to meet the demonstration objectives, and projected to maintain a fully operational payload for at least 10 years.

THE IMPORTANCE OF BUREAUCRACY STRUCTURE FACTOR IN THE IMPLEMENTATION OF MINIMUM STANDARD OF HEALTH SERVICE IN CENTRAL JAVA PROVINCE, INDONESIA

Directory of Open Access Journals (Sweden)

Mardianti N.I.

2017-11-01

Full Text Available This paper examines the phenomenon of incompatibility of the institutional structure of Regional Public Hospital which causes the disruption of the achievement of Minimum Service Standards (MSS indicator in the health sector, especially maternal health in the Provincial Government of Central Java. In Central Java, the largest number of maternal mortality rate was in the hospital in 2015 amounted to 85.71%. Meanwhile, the coverage rate of delivery assisted by health personnel in accordance with the indicator of MSS is 98.09%. In 2015, Central Java is the province with the second highest national of maternal mortality rate case amounted to 619 cases. The Provincial Government as the coordinator of MSS implementation in the region through the Bureau of Pemotda and the Cooperation of Regional Secretariat of Central Java has a significant role in the successful implementation of the Regulation of Minister of Health 43/2016 on MSS in Health Sector. In which MSS has a function to observe the implementation of health program in the region. This research uses a qualitative approach, the type of research is a case study and interactive model analysis from Miles, Huberman, and Saldana. The results of the analysis show that the implementation process of the policy in Bureau of Pemotda and the Cooperation of Regional Secretariat of Central Java has not run well obstructed by bureaucratic structure factor. It can be seen from the unfulfilled policy objective which is to provide convenience to local government in the preparation of planning document on the achievement of health MSS indicator. Although health MSS is achieved, it will not be able to reduce the maternal mortality rate.

NOAA Satellite and Information Service's International and Interagency

Science.gov (United States)

: To meet the challenge of understanding and predicting changes in climate, weather, oceans, and coasts Affaris Division Skip to main content NOAA HOME NESDIS HOME WEATHER OCEANS & COASTS FISHERIES CHARTING SATELLITES CLIMATE RESEARCH CAREERS Satellite and Data Policy Developing Partnerships

A new digital land mobile satellite system

Science.gov (United States)

Schneider, Philip

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

Application of MSS/LANDSAT images to the structural study of recent sedimentary areas: Campos Sedimentary Basin, Rio de Janeiro, Brazil

Science.gov (United States)

Parada, N. D. J. (Principal Investigator); Barbosa, M. P.

1983-01-01

Visual and computer aided interpretation of MSS/LANDSAT data identified linear and circular features which represent the ""reflexes'' of the crystalline basement structures in the Cenozoic sediments of the emergent part of the Campos Sedimentary Basin.

Satellite communication from user to user

Science.gov (United States)

Gern, Manfred

Satellite communication systems which allow a multitude of user-to-user, point-to-point, and multipoint connections, are presented. The bit rates are 64 kbit/sec and multiples, up to 1.92 Mbit/sec. If required, the ground-stations are installed at the customer's site or at suitable locations in order to serve several customers. However, technical requirements for station location have also to be fulfulled, in order to avoid interference with terrestrial radio services. The increasing number of participants to Satellite Multi Service and INTELSAT Business Services imposes the solution of the problem of communication using cheap techniques. The changes of the German Federal Post Office also permit the economic use of satellite radio techniques for short distances.

Experiment In Aeronautical-Mobile/Satellite Communication

Science.gov (United States)

Jedrey, Thomas C.; Lay, Norman E.; Dessouky, Khaled

1992-01-01

Report describes study of performance of digital mobile/satellite communication terminals of advanced design intended for use in ground stations and airplanes in aeronautical-mobile service. Study was collaboration of NASA, Federal Aviation Administration (FAA), Communications Satellite Corp. (COMSAT), and International Maritime Satellite System (INMARSAT).

Monitoring activities of satellite data processing services in real-time with SDDS Live Monitor

Science.gov (United States)

Duc Nguyen, Minh

2017-10-01

This work describes Live Monitor, the monitoring subsystem of SDDS - an automated system for space experiment data processing, storage, and distribution created at SINP MSU. Live Monitor allows operators and developers of satellite data centers to identify errors occurred in data processing quickly and to prevent further consequences caused by the errors. All activities of the whole data processing cycle are illustrated via a web interface in real-time. Notification messages are delivered to responsible people via emails and Telegram messenger service. The flexible monitoring mechanism implemented in Live Monitor allows us to dynamically change and control events being shown on the web interface on our demands. Physicists, whose space weather analysis models are functioning upon satellite data provided by SDDS, can use the developed RESTful API to monitor their own events and deliver customized notification messages by their needs.

A 10-bit 50-MS/s subsampling pipelined ADC based on SMDAC and opamp sharing

Energy Technology Data Exchange (ETDEWEB)

Chen Lijie; Zhou Yumei; Wei Baoyue, E-mail: frankdhz@yahoo.com.cn [Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China)

2010-11-15

This paper describes a 10-bit, 50-MS/s pipelined A/D converter (ADC) with proposed area- and power-efficient architecture. The conventional dedicated sample-hold-amplifier (SHA) is eliminated and the matching requirement between the first multiplying digital-to-analog converter (MDAC) and sub-ADC is also avoided by using the SHA merged with the first MDAC (SMDAC) architecture, which features low power and stabilization. Further reduction of power and area is achieved by sharing an opamp between two successive pipelined stages, in which the effect of opamp offset and crosstalk between stages is decreased. So the 10-bit pipelined ADC is realized using just four opamps. The ADC demonstrates a maximum signal-to-noise distortion ratio and spurious free dynamic range of 52.67 dB and 59.44 dB, respectively, with a Nyquist input at full sampling rate. Constant dynamic performance for input frequencies up to 49.7 MHz, which is the twofold Nyquist rate, is achieved at 50 MS/s. The ADC prototype only occupies an active area of 1.81 mm{sup 2} in a 0.35 {mu}m CMOS process, and consumes 133 mW when sampling at 50 MHz from a 3.3-V power supply.

High power communication satellites power systems study

International Nuclear Information System (INIS)

Josloff, A.T.; Peterson, J.R.

1994-01-01

This paper discusses a DOE-funded study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. This study brings together a preeminent US Industry/Russian team to cooperate on the role of high power communication satellites in the rapidly expanding communications revolution. These high power satellites play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities will be significant

High power communication satellites power systems study

Science.gov (United States)

Josloff, Allan T.; Peterson, Jerry R.

1995-01-01

This paper discusses a planned study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. These high power satellites can play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities can be significant.

Satellite power system in the service of man

Energy Technology Data Exchange (ETDEWEB)

Hyde, F.W.

1981-01-01

The solar power satellite concept is discussed in its various aspects: technical assumptions; unit power output; economic impact; impact on resources; environmental impacts; primary system functions; transmission of energy to earth; reception and conversion to usable energy on earth; space transport; station-keeping and attitude control; fabrication and assembly in space; power beam phase control; satellite maintenance; ancillary functions at rectenna site; and emerging technologies.

Monitoring activities of satellite data processing services in real-time with SDDS Live Monitor

Directory of Open Access Journals (Sweden)

Duc Nguyen Minh

2017-01-01

Full Text Available This work describes Live Monitor, the monitoring subsystem of SDDS – an automated system for space experiment data processing, storage, and distribution created at SINP MSU. Live Monitor allows operators and developers of satellite data centers to identify errors occurred in data processing quickly and to prevent further consequences caused by the errors. All activities of the whole data processing cycle are illustrated via a web interface in real-time. Notification messages are delivered to responsible people via emails and Telegram messenger service. The flexible monitoring mechanism implemented in Live Monitor allows us to dynamically change and control events being shown on the web interface on our demands. Physicists, whose space weather analysis models are functioning upon satellite data provided by SDDS, can use the developed RESTful API to monitor their own events and deliver customized notification messages by their needs.

Site-characterization information using LANDSAT satellite and other remote-sensing data: integration of remote-sensing data with geographic information systems. A case study in Pennsylvania

International Nuclear Information System (INIS)

Campbell, W.J.; Imhoff, M.L.; Robinson, J.; Gunther, F.; Boyd, R.; Anuta, M.

1983-06-01

The utility and cost effectiveness of incorporating digitized aircraft and satellite remote sensing data into a geographic information system for facility siting and environmental impact assessments was evaluated. This research focused on the evaluation of several types of multisource remotely sensed data representing a variety of spectral band widths and spatial resolution. High resolution aircraft photography, Landsat MSS, and 7 band Thematic Mapper Simulator (TMS) data were acquired, analyzed, and evaluated for their suitability as input to an operational geographic information system (GIS). 78 references, 59 figures, 74 tables

An Effort to Map and Monitor Baldcypress Forest Areas in Coastal Louisiana, Using Landsat, MODIS, and ASTER Satellite Data

Science.gov (United States)

Spruce, Joseph P.; Sader, Steve; Smoot, James

2012-01-01

This presentation discusses a collaborative project to develop, test, and demonstrate baldcypress forest mapping and monitoring products for aiding forest conservation and restoration in coastal Louisiana. Low lying coastal forests in the region are being negatively impacted by multiple factors, including subsidence, salt water intrusion, sea level rise, persistent flooding, hydrologic modification, annual insect-induced forest defoliation, timber harvesting, and conversion to urban land uses. Coastal baldcypress forests provide invaluable ecological services in terms of wildlife habitat, forest products, storm buffers, and water quality benefits. Before this project, current maps of baldcypress forest concentrations and change did not exist or were out of date. In response, this project was initiated to produce: 1) current maps showing the extent and location of baldcypress dominated forests; and 2) wetland forest change maps showing temporary and persistent disturbance and loss since the early 1970s. Project products are being developed collaboratively with multiple state and federal agencies. Products are being validated using available reference data from aerial, satellite, and field survey data. Results include Landsat TM- based classifications of baldcypress in terms of cover type and percent canopy cover. Landsat MSS data was employed to compute a circa 1972 classification of swamp and bottomland hardwood forest types. Landsat data for 1972-2010 was used to compute wetland forest change products. MODIS-based change products were applied to view and assess insect-induced swamp forest defoliation. MODIS, Landsat, and ASTER satellite data products were used to help assess hurricane and flood impacts to coastal wetland forests in the region.

Satellite Technologies and Services: Implications for International Distance Education.

Science.gov (United States)

Stahmer, Anna

1987-01-01

This examination of international distance education and open university applications of communication satellites at the postsecondary level notes activities in less developed countries (LDCs); presents potential models for cooperation; and describes technical systems for distance education, emphasizing satellite technology and possible problems…

New Generation of Broadcasting Satellite Systems: New Markets and Business Developments

Science.gov (United States)

Perrot, Bruno; Michel, Cyril; Villaret, Stéfanie

2002-01-01

Since the deployment of the first Digital Broadcasting Satellite Systems, European satellite operators and service providers have been faced with the continuously increasing demand for Digital Broadcasting Services. Their success is built on the availability of the MPEG and DVB standards. Undoubtedly, conventional digital television broadcasting is today the `Killer' application. Various service providers already offer multimedia applications through DVB-S systems based upon the `Push' technology. Although these services do not currently represent the core business for broadcasting satellite operators, their percentage is increasing. `Push' technology services include Data Carousel, Webcasting, Turbo Internet, File casting and so on. Such technology can support the implementation of different emerging multimedia services scenarios from Newsgroups, Network collaborative learning, and tele-medicine, to others that may be invented in the near future. The penetration rate of multi-channel television reception is still increasing. Broadcasting satellites benefit both from the development of new, more segmented and sophisticated offers and from the development of Internet services. Satellite is likely to enter these new markets at different levels of the value chain: Even if the satellite has demonstrated its capacity to fully serve the television, combinations with other networks may be necessary to address the new markets: at the consumer premises, Internet-related services will require a return path; at the backbone level, satellite becomes a component of a full telecommunications solution. This article focuses on the European market and proposes:

Advanced Communications Technology Satellite (ACTS) and potential system applications

Science.gov (United States)

Wright, David L.; Balombin, Joseph R.; Sohn, Philip Y.

1990-01-01

A description of the advanced communications technology satellite (ACTS) system is given with special emphasis on the communication characteristics. Potential satellite communications scenarios, including future operational ACTS-like satellite systems, are discussed. The description of the ACTS system updates previously published ACTS system references. Detailed information on items such as experimental ground stations is presented. The potential services can be generically described as voice, video, and data services. The implementation of these services on future operational ACTS-like systems can lead to unique quality, flexibility, and capacity characteristics at lower service costs. The specific service applications that could be supported range from low to high data rates and include both domestic and international applications.

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.

The use of Landsat-4 MSS digital data in temporal data sets and the evaluation of scene-to-scene registration accuracy

Science.gov (United States)

Anderson, J. E.

1985-01-01

The MSS sensor on Landsat 4 is, in certain performance aspects, diferent from those of Landsats 1 through 3. These differences created some concern in the NASA research community as to whether individual data sets can be registered accurately enough to produce acceptable data sets for multitemporal data analysis. The use of Landsat 4 MSS digital data in temporal data sets is examined and a method is presented for estimating temporal registration accuracy based on the use of an X-Y digitizer and grey tone electrostatic plots. Results indicate that the RMS temporal registration errors are not significantly different from the temporal data sets generated using Landsat 4 and Landsat 2 data (33.35 meters) and the temporal data set constructed from two Landsat 2 data sets (33.61 meters). A derivation of the model used to evaluate the temporal registration is included.

Assessing Family Planning Service Quality And User Experiences In Social Franchising Programme - Case Studies From Two Rural Districts In Pakistan.

Science.gov (United States)

Azmat, Syed Khurram; Ali, Moazzam; Hameed, Waqas; Awan, Muhammad Ali

2018-01-01

Studies have documented the impact of quality family planning services on improved contraceptive uptake and continuation, however, relatively little is known about their quality of service provision especially in the context of social franchising. This study examined the quality of clinical services and user experiences among two models in franchised service providers in rural Pakistan. This facility-based assessment was carried out during May-June 2015 at the 20 randomly selected social franchise providers from Chakwal and Faisalabad. In our case, a franchise health facility was a private clinic (mostly) run by a single provider, supported by an assistant. Within the selected health facilities, a total 39 user-provider interactions were observed and same users were interviewed separately. Most of the health facilities were in the private sector. Comparatively, service providers at Greenstar Social Marketing/Population Services International (GSM/PSI) model franchised facilities had higher number of rooms and staff employed, with more providers' ownership. Quality of service indices showed high scores for both Marie Stopes Society (MSS) and GSM/PSI franchised providers. MSS franchised providers demonstrated comparative edge in terms of clinical governance, better method mix and they were more user-focused, while PSI providers offered broader range of non-FP services. Quality of counselling services were similar among both models. Service providers performed well on all indicators of interpersonal care however overall low scores were noted in technical care. For both models, service providers attained an average score of 6.7 (out of the maximum value of 8) on waste disposal mechanism, supplies 12.5 (out of the maximum value of 15), user-centred facility 2.7 (out of the maximum value of 4), and clinical governance 6.5 (out of the maximum value of 11) and respecting clients' privacy. The exit interviews yielded high user satisfaction in both service models. The

HAPS Gateway Link in the 5850-7075 MHz and Coexistence with Fixed Satellite Service

Directory of Open Access Journals (Sweden)

M. Ahmed

2013-09-01

Full Text Available Gateway link is essential to connect HAPS platform to terrestrial based networks. This crucial link is incorporated in HAPS fixed service spectrum allocation in considerably high frequencies, renders the link for more attenuations by atmospheric gases, and rain effects, especially when the regional climate is not favorable. However, under the agenda item 1.20 of World Radio Conference-2012 (WRC-12 new HAPS allocation in the 5850-7075 MHz band is proposed. Although, spectrum features are incomparably reliable, on the contrary, Fixed Satellite Service (FSS uplink transmissions will have signal levels much higher than those in HAPS systems and have the potential for causing interference at the HAPS gateway receiver. In this article a key aspect of co-channel interference phenomena is investigated to facilitate optimum frequency sharing in the band in question. By proposing mitigation techniques and statistical method this generic prediction model enhances the capability of the HAPS spectrum sharing and provides flexibility in spectrum planning for different fixed services.

TYCHO: Demonstrator and operational satellite mission to Earth-Moon-Libration point EML-4 for communication relay provision as a service

Science.gov (United States)

Hornig, Andreas; Homeister, Maren

2015-03-01

In the current wake of mission plans to the Moon and to Earth-Moon Libration points (EML) by several agencies and organizations, TYCHO identifies the key role of telecommunication provision for the future path of lunar exploration. It demonstrates an interesting extension to existing communication methods to the Moon and beyond by combining innovative technology with a next frontier location and the commercial space communication sector. It is evident that all communication systems will rely on direct communication to Earth ground stations. In case of EML-2 missions around HALO orbits or bases on the far side of the Moon, it has to be extended by communication links via relay stations. The innovative approach is that TYCHO provides this relay communication to those out-of-sight lunar missions as a service. TYCHO will establish a new infrastructure for future missions and even create a new market for add-on relay services. The TMA-0 satellite is TYCHO's first phase and a proposed demonstrator mission to the Earth-Moon Libration point EML-4. It demonstrates relay services needed for automated exploratory and manned missions (Moon bases) on the rim (>90°E and >90°W) and far side surface, to lunar orbits and even to EML-2 halo orbits (satellites and space stations). Its main advantage is the permanent availability of communication coverage. This will provide full access to scientific and telemetry data and furthermore to crucial medical monitoring and safety. The communication subsystem is a platform for conventional communication but also a test-bed for optical communication with high data-rate LASER links to serve the future needs of manned bases and periodic burst data-transfer from lunar poles. The operational TMA-1 satellite is a stand-alone mission integrated into existing space communication networks to provide open communication service to external lunar missions. Therefore the long-time stable libration points EML-4 and -5 are selected to guarantee an

MoMoSat -- Mobile Service for Monitoring with GeoNotes via Satellite

Energy Technology Data Exchange (ETDEWEB)

Niemeyer, Irmgard [Forschungszentrum Juelich (Germany). Programme Group Systems Analysis and Technology Evaluation (STE); Jonas, Karl [Univ. of Applied Science Bonn-Rhein-Sieg, Sankt Augustin (Germany). FhG FOKUS CC SATCom; Horz, Alexander [horz informatik, Sankt Augustin (Germany); Wettschereck, Dietrich; Schmidt, Dirk [DIALOGIS GmbH, Bonn (Germany)

2003-05-01

The MoMoSat service will enable mobile end-users to view, manage, annotate, and communicate mapbased information in the field. The handled information exists of a huge volume of raster (satellite or aerial images) and vector data (i.e. street networks, cadastral maps or points of interest), as well as text-specific geo-referenced textual notes (the so-called 'GeoNotes') and real-time voice. A secure real-time communication between mobile units and the primary data store is an essential task of the MoMoSat service. The basic information is stored in the primary database that is accessible through a virtual private network (VPN) and cached at a server at a base station in order to ensure data availability. The base station may be installed in a car or another mobile vehicle. The two servers will periodically communicate with each other via secure satellite communication in order to check for updates. The base station supplies the relevant GIS data for the mobile units (people or even robots in the field at remote solutions). The communication between the mobile units is based on a peer-to-peer wireless local area network (WLAN) architecture. The mobile units are equipped with mobile computers (i.e. laptop, tablet PC or PDA) combined with a satellite-based positioning system (GPS) that enables them to request the proper geographic data sets from yhe base station's map server. An interactive mapping software shows the actual location on the map and allows the user to navigate (zoom, pan) through the high-resolution map display. The user can switch 'on' or 'off' several thematic layers (i.e. street network or points of interest) on the map. The software also supports collaborative aspects of MoMoSat by offering tools for the management of the GeoNotes that can be visualized by categories. The user can extend the existing GeoNotes with his personnel comments or create new GeoNotes by defining categories, recipients and the level of

Monitoring Environment with GIS for Part of Thiruvallur Town Using Cartosat 1 Stereo, Pan & Resourcesat Liss 4 MSS Merged Data

Science.gov (United States)

Mohamed, G. S.; Venkatchalam, R. V.; Ramamurthhy, M.; Gummidipoondi, R. J.; Ramillah, M.

2012-07-01

of Thiruvallur Municipality Area between North Western Thiruvallur town from the Temple Tank of Sri Veeraragavasamy temple to junction of National Highways connecting Thiruvallur to Tirupathi and Thiruvallur- Poondi- Uthukottai at the West. These data are used to create environment monitoring GIS to understand the use of High resolution Indian satellite data for local urban environmental planning to manage the health and environmental issues. ARC GIS 10 and Lieca photogrammetry software are used with satellite data to create different layer for creating GIS on urban infrastructure like houses, public buildings, roads, municipal surface drainage net work, underground sewerage drainage net work, drinking water pipe lines net work, landfills, solid waste disposal yards, pumping stations, degraded areas, heath services infrastructure, wet lands , low lying areas with bushes, abandoned lakes which are the breeding grounds for mosquito's in rainy season, etc These layers are correlated with the municipal ward map of this segment of the town. The stereo data of Cartosat 1 is useful for mapping the households, roads, agricultural fields, bushy areas, slopes to map the natural drainage of the area and for delineation of micro watersheds. When the layer of municipal ward maps are integrated with the GIS the drainage, drinking water lines, street names and house numbers etc can be added to the attribute data to make this as a complete Environment management GIS. The use of PAN merged data of Cartosat 1 with LISS 4, MSS Resourcesat 1 in natural colour and it's cost effectiveness is studied to explain the usefulness of creation of Environment Health GIS. The non stereo Geo Eye latest data from Google Earth web site or Cartosat 2 can be used for upgrading the land use changes and identify current environmental as on 2011.The study will provide GIS to monitor environmental issues with multi date large scale data for Thiruvallur Town.

Newspaper Uses of Satellite Technology.

Science.gov (United States)

Johns, David

Replacing slower mail service, satellite transmission now gives the newspaper industry a practical and almost spontaneous method for sending all kinds of information to any newspaper across the country. Unlike other communication industries, newspapers did not begin to make widespread use of satellite technology until 1979, when government…

ECOSPACE : a pre-operational satellite system and services for ocean colour monitoring

Science.gov (United States)

Morel, André; Cerutti-Maori, Guy; Morel, Michel

2017-11-01

A permanent monitoring of the oceanic algal biomass (phytoplankton), of its photosynthetic activity, ecological and biogeochemical impact, or of its long-term response to changing physical and climatic conditions, is a crucial goal of scientific programmes (such as JGOFS, GLOBEC, LOICZ), as well as of international observing systems (such as GOOS, GCOS, IGOS). After a decade without ocean colour satellite-borne sensor, several instruments have been, or will be launched. They are increasingly sophisticated in their design and operation. Their complexity results from constraints for multipurpose mission (involving not only ocean, but also land and atmosphere), or from requirements for exploratory research projects and development of new methodologies for improved ocean colour interpretation and "advanced" products. In contrast, the proposed specific ECOSPACE mission is an ocean colour dedicated instrument, with a global monitoring vocation. It relies on known algorithms for accurate atmospheric corrections and aerosol load estimate over open ocean (about 96% of the whole ocean), and known algorithms for a meaningful quantification of the oceanic algal biomass (in terms of Chlorophyll concentration). The coastal zones are observed as well, and their particular features delineated : however, detailed studies that imply high ground resolution and more spectral channels are out of the scope of the present proposal. The ECOSPACE mission represents a feasibility demonstration ; more precisely it is a first step toward the setting up of an operational Satellite System and Services for a future continuous supply of stable, compatible, easy-to-merge ocean colour date products. In essence, such a Service would be similar to those already existing for meteorology and for some oceanic variables (e.g. sea level). Although new approaches to management and implementation over a short time scale are needed, the ECOSPACE project relies essentially on existing scientific and

The method of quick satellite aiming with 3-Steps on the mobile satellite station

Directory of Open Access Journals (Sweden)

Sheng Liang

2017-02-01

Full Text Available The study analyses and concludes the technology of the satellite aiming during real-time broadcast of mobile video.We conclude a method of quick satellite aiming with 3-steps according to practical exercises and users' requirement to meet situation of facts and standardized operation,which can improve efficiency and quality of service.

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

An Assessment of State-of-the-Art Mean Sea Surface and Geoid Models of the Arctic Ocean: Implications for Sea Ice Freeboard Retrieval

Science.gov (United States)

Skourup, Henriette; Farrell, Sinéad Louise; Hendricks, Stefan; Ricker, Robert; Armitage, Thomas W. K.; Ridout, Andy; Andersen, Ole Baltazar; Haas, Christian; Baker, Steven

2017-11-01

State-of-the-art Arctic Ocean mean sea surface (MSS) models and global geoid models (GGMs) are used to support sea ice freeboard estimation from satellite altimeters, as well as in oceanographic studies such as mapping sea level anomalies and mean dynamic ocean topography. However, errors in a given model in the high-frequency domain, primarily due to unresolved gravity features, can result in errors in the estimated along-track freeboard. These errors are exacerbated in areas with a sparse lead distribution in consolidated ice pack conditions. Additionally model errors can impact ocean geostrophic currents, derived from satellite altimeter data, while remaining biases in these models may impact longer-term, multisensor oceanographic time series of sea level change in the Arctic. This study focuses on an assessment of five state-of-the-art Arctic MSS models (UCL13/04 and DTU15/13/10) and a commonly used GGM (EGM2008). We describe errors due to unresolved gravity features, intersatellite biases, and remaining satellite orbit errors, and their impact on the derivation of sea ice freeboard. The latest MSS models, incorporating CryoSat-2 sea surface height measurements, show improved definition of gravity features, such as the Gakkel Ridge. The standard deviation between models ranges 0.03-0.25 m. The impact of remaining MSS/GGM errors on freeboard retrieval can reach several decimeters in parts of the Arctic. While the maximum observed freeboard difference found in the central Arctic was 0.59 m (UCL13 MSS minus EGM2008 GGM), the standard deviation in freeboard differences is 0.03-0.06 m.

Volumetrically-Derived Global Navigation Satellite System Performance Assessment from the Earths Surface through the Terrestrial Service Volume and the Space Service Volume

Science.gov (United States)

Welch, Bryan W.

2016-01-01

NASA is participating in the International Committee on Global Navigation Satellite Systems (GNSS) (ICG)'s efforts towards demonstrating the benefits to the space user from the Earth's surface through the Terrestrial Service Volume (TSV) to the edge of the Space Service Volume (SSV), when a multi-GNSS solution space approach is utilized. The ICG Working Group: Enhancement of GNSS Performance, New Services and Capabilities has started a three phase analysis initiative as an outcome of recommendations at the ICG-10 meeting, in preparation for the ICG-11 meeting. The first phase of that increasing complexity and fidelity analysis initiative was recently expanded to compare nadir-facing and zenith-facing user hemispherical antenna coverage with omnidirectional antenna coverage at different distances of 8,000 km altitude and 36,000 km altitude. This report summarizes the performance using these antenna coverage techniques at distances ranging from 100 km altitude to 36,000 km to be all encompassing, as well as the volumetrically-derived system availability metrics.

The HSBQ Algorithm with Triple-play Services for Broadband Hybrid Satellite Constellation Communication System

Directory of Open Access Journals (Sweden)

Anupon Boriboon

2016-07-01

Full Text Available The HSBQ algorithm is the one of active queue management algorithms, which orders to avoid high packet loss rates and control stable stream queue. That is the problem of calculation of the drop probability for both queue length stability and bandwidth fairness. This paper proposes the HSBQ, which drop the packets before the queues overflow at the gateways, so that the end nodes can respond to the congestion before queue overflow. This algorithm uses the change of the average queue length to adjust the amount by which the mark (or drop probability is changed. Moreover it adjusts the queue weight, which is used to estimate the average queue length, based on the rate. The results show that HSBQ algorithm could maintain control stable stream queue better than group of congestion metric without flow information algorithm as the rate of hybrid satellite network changing dramatically, as well as the presented empiric evidences demonstrate that the use of HSBQ algorithm offers a better quality of service than the traditionally queue control mechanisms used in hybrid satellite network.

An approach to effective UHF (S/L band) data communications for satellite Personal Communication Service (PCS)

Science.gov (United States)

Hayase, Joshua Y.

1995-01-01

Reliable signaling information transfer is fundamental in supporting the needs of data communication PCS via LMS (Land Mobile Service) SSs (satellite systems). The needs of the system designer can be satisfied only through the collection of media information that can be brought to bear on the pertinent design issues. We at ISI hope to continue our dialogue with fading media experts to address the unique data communications needs of PCS via LMS SSs.

Plan of Time Management of Satellite Positioning System using Quasi-zenith Satellite

Science.gov (United States)

Takahashi, Yasuhiro; Fujieda, Miho; Amagai, Jun; Yokota, Shoichiro; Kimura, Kazuhiro; Ito, Hiroyuki; Hama, Shin'ichi; Morikawa, Takao; Kawano, Isao; Kogure, Satoshi

The Quasi-Zenith satellites System (QZSS) is developed as an integrated satellite service system of communication, broadcasting and positioning for mobile users in specified regions of Japan from high elevation angle. Purposes of the satellite positioning system using Quasi-Zenith satellite (QZS) are to complement and augment the GPS. The national institutes concerned have been developing the positioning system using QZS since 2003 and will carry out experiments and researches in three years after the launch. In this system, National Institute of Information and Communications Technology (NICT) is mainly in charge of timing system for the satellite positioning system using QZS, such as onboard hydrogen maser atomic clock and precise time management system of the QZSS. We started to develop the engineering model of the time management system for the QZSS. The time management system for the QZSS will be used to compare time differences between QZS and earth station as well as to compare between three onboard atomic clocks. This paper introduces time management of satellite positioning system using the QZSS.

Advanced mobile satellite communications using COMETS satellite in MM-wave and Ka-band

Science.gov (United States)

Ohmori, Shingo; Isobe, Shunkichi; Takeuchi, Makoto; Naito, Hideyuki

1993-01-01

Early in the 21st century, the demand for personal communications using mobile, hand-held, and VSAT terminals will rapidly increase. In a future system, many different types of services should be provided with one-hop connection. The Communications Research Laboratory (CRL) has studied a future advanced mobile satellite communications system using millimeter wave and Ka band. In 1990, CRL started the Communications and Broadcasting Engineering Test Satellite (COMETS) project. The satellite has been developed in conjunction with NASDA and will be launched in 1997. This paper describes the COMETS payload configuration and the experimental system for the advanced mobile communications mission.

After 10 years of service, NOAA retires GOES-12 satellite

Science.gov (United States)

NOAA HOME WEATHER OCEANS FISHERIES CHARTING SATELLITES CLIMATE RESEARCH COASTS CAREERS National oceans. In addition to GOES, NOAA also operates the polar operational environmental satellite (POES spacecraft. NOAA's mission is to understand and predict changes in the Earth's environment, from the depths

Many Saccharomyces cerevisiae Cell Wall Protein Encoding Genes Are Coregulated by Mss11, but Cellular Adhesion Phenotypes Appear Only Flo Protein Dependent.

Science.gov (United States)

Bester, Michael C; Jacobson, Dan; Bauer, Florian F

2012-01-01

The outer cell wall of the yeast Saccharomyces cerevisiae serves as the interface with the surrounding environment and directly affects cell-cell and cell-surface interactions. Many of these interactions are facilitated by specific adhesins that belong to the Flo protein family. Flo mannoproteins have been implicated in phenotypes such as flocculation, substrate adhesion, biofilm formation, and pseudohyphal growth. Genetic data strongly suggest that individual Flo proteins are responsible for many specific cellular adhesion phenotypes. However, it remains unclear whether such phenotypes are determined solely by the nature of the expressed FLO genes or rather as the result of a combination of FLO gene expression and other cell wall properties and cell wall proteins. Mss11 has been shown to be a central element of FLO1 and FLO11 gene regulation and acts together with the cAMP-PKA-dependent transcription factor Flo8. Here we use genome-wide transcription analysis to identify genes that are directly or indirectly regulated by Mss11. Interestingly, many of these genes encode cell wall mannoproteins, in particular, members of the TIR and DAN families. To examine whether these genes play a role in the adhesion properties associated with Mss11 expression, we assessed deletion mutants of these genes in wild-type and flo11Δ genetic backgrounds. This analysis shows that only FLO genes, in particular FLO1/10/11, appear to significantly impact on such phenotypes. Thus adhesion-related phenotypes are primarily dependent on the balance of FLO gene expression.

Use of topographic and climatological models in a geographical data base to improve Landsat MSS classification for Olympic National Park

Science.gov (United States)

Cibula, William G.; Nyquist, Maurice O.

1987-01-01

An unsupervised computer classification of vegetation/landcover of Olympic National Park and surrounding environs was initially carried out using four bands of Landsat MSS data. The primary objective of the project was to derive a level of landcover classifications useful for park management applications while maintaining an acceptably high level of classification accuracy. Initially, nine generalized vegetation/landcover classes were derived. Overall classification accuracy was 91.7 percent. In an attempt to refine the level of classification, a geographic information system (GIS) approach was employed. Topographic data and watershed boundaries (inferred precipitation/temperature) data were registered with the Landsat MSS data. The resultant boolean operations yielded 21 vegetation/landcover classes while maintaining the same level of classification accuracy. The final classification provided much better identification and location of the major forest types within the park at the same high level of accuracy, and these met the project objective. This classification could now become inputs into a GIS system to help provide answers to park management coupled with other ancillary data programs such as fire management.

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.

A series on optimizing satellite systems. I - Restoring interruptions of communications sattelite service: Logistical and cost comparisons of mature and newly operational systems

Science.gov (United States)

Snow, Marcellus S.

1989-09-01

A mathematical model is presented of costs and operational factors involved in provision for service interruptions of both a mature and typically large incumbent satellite system and of a smaller, more recently operational system. The equation expresses the required launch frequency for the new system as a function of the launch spacing of the mature system; the time disparity between the inauguration of the two systems; and the rate of capacity depreciation. In addition, a technique is presented to compare the relative extent to which the discounted costs of the new system exceed those of the mature system in furnishing the same effective capacity in orbit, and thus the same service liability, at a given point in time. It is determined that a mature incumbent communications satellite system, having more capacity in orbit, will on balance have a lower probability of service interruption than a newer, smaller system.

Reservation centre of Telecom I satellite French Telecommunication network offers a new service of switched digital circuit

Science.gov (United States)

Felix, J.

The management center and new circuit switching services offered by the French Telecom I network are described. Attention is focused on business services. The satellite has a 125 Mbit/sec capability distributed over 5 frequency bands, yielding the equivalent of 1800 channels. Data are transmitted in digitized bursts with TDMA techniques. Besides the management center, Telecom I interfaces with 310 local network antennas with access managed by the center through a reservation service and protocol assignment. The center logs and supervises alarms and network events, monitors traffic, logs taxation charges and manages the man-machine dialog for TDMA and terrestrial operations. Time slots are arranged in terms of minimal 10 min segments. The reservations can be directly accessed by up to 1000 terminals. All traffic is handled on a call-by-call basis.

Satellite failures revisited

Science.gov (United States)

Balcerak, Ernie

2012-12-01

In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.

Light Detection and Ranging (LiDAR and Multispectral Scanner (MSS Studies Examine Coastal Environments Influenced by Mining

Directory of Open Access Journals (Sweden)

W. Charles Kerfoot

2014-01-01

Full Text Available There are numerous examples of past and present mine disposal into freshwater and marine coastal bays and riverine environments. Due to its high spatial resolution and extended water penetration, coastal light detection and ranging (LiDAR, coupled with multispectral scanning (MSS, has great promise for resolving disturbed shoreline features in low turbidity environments. Migrating mine tailings present serious issues for Lake Superior and coastal marine environments. Previous investigations in Lake Superior uncovered a metal-rich “halo” around the Keweenaw Peninsula, related to past copper mining practices. For over a century, waste rock migrating from shoreline tailing piles has moved along extensive stretches of coastline, compromising critical fish breeding grounds, damming stream outlets, transgressing into wetlands and along recreational beaches and suppressing benthic invertebrate communities. In Grand (Big Traverse Bay, Buffalo Reef is an important spawning area for lake trout and whitefish threatened by drifting tailings. The movement of tailings into Buffalo Reef cobble fields may interfere with the hatching of fish eggs and fry survival, either by filling in crevices where eggs are deposited or by toxic effects on eggs, newly hatched larvae or benthic communities. Here, we show that the coastal tailing migration is not “out of sight, out of mind”, but clearly revealed by using a combination of LiDAR and MSS techniques.

14-bit 100 MS/s 121 mW pipelined ADC

International Nuclear Information System (INIS)

Chen Yongzhen; Chen Chixiao; Feng Zemin; Ye Fan; Ren Junyan

2015-01-01

This paper presents a high-speed high-resolution pipelined ADC with low power and small area. The proposed ADC is designed based on the analysis of the stage scaling theory and the residual amplifiers are shared by two cascading MDACs to reduce power consumption. Shared op-amps with two split input paths are presented in this paper to eliminate the nonlinearity effects such as memory effect and crosstalk. Dynamic pre-amplified comparators are employed to decrease the static power consumption and suppress the kick-back in the comparators. This ADC is implemented in SMIC 0.18 μm CMOS process with an area of 3.1 mm 2 . With a sampling rate of 100 MS/s, spurious-free dynamic range (SFDR) and signal-to-noise plus distortion ratio (SNDR) of the ADC are 82.7 dB and 69.1 dB, respectively. For signals up to 100 MHz, the SFDR and SNDR achieve 81.4 dB and 65.8 dB. The power consumption is 121 mW with a 1.8 V supply voltage. (paper)

Mechanistic study on the nuclear modifier gene MSS1 mutation suppressing neomycin sensitivity of the mitochondrial 15S rRNA C1477G mutation in Saccharomyces cerevisiae.

Science.gov (United States)

Zhou, Qiyin; Wang, Wei; He, Xiangyu; Zhu, Xiaoyu; Shen, Yaoyao; Yu, Zhe; Wang, Xuexiang; Qi, Xuchen; Zhang, Xuan; Fan, Mingjie; Dai, Yu; Yang, Shuxu; Yan, Qingfeng

2014-01-01

The phenotypic manifestation of mitochondrial DNA (mtDNA) mutations can be modulated by nuclear genes and environmental factors. However, neither the interaction among these factors nor their underlying mechanisms are well understood. The yeast Saccharomyces cerevisiae mtDNA 15S rRNA C1477G mutation (PR) corresponds to the human 12S rRNA A1555G mutation. Here we report that a nuclear modifier gene mss1 mutation suppresses the neomycin-sensitivity phenotype of a yeast C1477G mutant in fermentable YPD medium. Functional assays show that the mitochondrial function of the yeast C1477G mutant was impaired severely in YPD medium with neomycin. Moreover, the mss1 mutation led to a significant increase in the steady-state level of HAP5 (heme activated protein), which greatly up-regulated the expression of glycolytic transcription factors RAP1, GCR1, and GCR2 and thus stimulated glycolysis. Furthermore, the high expression of the key glycolytic enzyme genes HXK2, PFK1 and PYK1 indicated that enhanced glycolysis not only compensated for the ATP reduction from oxidative phosphorylation (OXPHOS) in mitochondria, but also ensured the growth of the mss1(PR) mutant in YPD medium with neomycin. This study advances our understanding of the phenotypic manifestation of mtDNA mutations.

Integration of Satellite and Terrestrial Systems in Future Multimedia Communications

OpenAIRE

Evans, Barry; Werner, Markus; Lutz, Erich; Bousquet, Michel; Corazza, Giovanni E; Maral, Gerard; Rumeau, Robert; Ferro, Erina

2005-01-01

In this article we examine the role of satellite communications in future telecommunication networks and service provision. Lessons from the past indicate that satellites are successful as a result of their wide area coverage or speed to market for new services. Niche areas such as coverage of air and sea will persist, but for land masses convergence of fixed, mobile, and broadcasting will dictate that the only way forward for satellites is in an integrated format with terrestrial systems. We...

Proposed systems configurations for a satellite based ISDN

Science.gov (United States)

Capece, M.; Pavesi, B.; Tozzi, P.; Galligan, K. P.

This paper summarizes concepts developed during a study for the ESA in which the evolution of ISDN capability and the impact in the satellite land mobile area are examined. Following the progressive steps of the expected ISDN implementation and the potential market penetration, a space based system capable of satisfying particular user services classes has been investigated. The approach used is to establish a comparison between the requirements of potential mobile users and the services already envisaged by ISDN, identifying the service subclasses that might be adopted in a mobile environment through a satellite system. Two system alternatives, with different ISDN compatibility, have been identified. The first option allows a partial compatibility, by providing the central stations of the earth segment with suitable interface units. The second option permits a full integration, operating on the satellite on-board capabilities.

Analysis of Decadal Vegetation Dynamics Using Multi-Scale Satellite Images

Science.gov (United States)

Chiang, Y.; Chen, K.

2013-12-01

This study aims at quantifying vegetation fractional cover (VFC) by incorporating multi-resolution satellite images, including Formosat-2(RSI), SPOT(HRV/HRG), Landsat (MSS/TM) and Terra/Aqua(MODIS), to investigate long-term and seasonal vegetation dynamics in Taiwan. We used 40-year NDVI records for derivation of VFC, with field campaigns routinely conducted to calibrate the critical NDVI threshold. Given different sensor capabilities in terms of their spatial and spectral properties, translation and infusion of NDVIs was used to assure NDVI coherence and to determine the fraction of vegetation cover at different spatio-temporal scales. Based on the proposed method, a bimodal sequence of intra-annual VFC which corresponds to the dual-cropping agriculture pattern was observed. Compared to seasonal VFC variation (78~90%), decadal VFC reveals moderate oscillations (81~86%), which were strongly linked with landuse changes and several major disturbances. This time-series mapping of VFC can be used to examine vegetation dynamics and its response associated with short-term and long-term anthropogenic/natural events.

Structural mapping from MSS-LANDSAT imagery: A proposed methodology for international geological correlation studies

Science.gov (United States)

Dejesusparada, N. (Principal Investigator); Crepani, E.; Martini, P. R.

1980-01-01

A methodology is proposed for international geological correlation studies based on LANDSAT-MSS imagery, Bullard's model of continental fit and compatible structural trends between Northeast Brazil and the West African counterpart. Six extensive lineaments in the Brazilian study area are mapped and discussed according to their regional behavior and in relation to the adjacent continental margin. Among the first conclusions, correlations were found between the Sobral Pedro II Lineament and the megafaults that surround the West African craton; and the Pernambuco Lineament with the Ngaurandere Linemanet in Cameroon. Ongoing research to complete the methodological stages includes the mapping of the West African structural framework, reconstruction of the pre-drift puzzle, and an analysis of the counterpart correlations.

A Generalized Visual Aid System for Teleoperation Applied to Satellite Servicing

Directory of Open Access Journals (Sweden)

Guoliang Zhang

2014-02-01

Full Text Available This paper presents the latest results of a newly developed visual aid system for direct teleoperation. This method is extended to visual control to make an efficient teleoperation system by combining direct teleoperation and automatic control. On the one hand, an operator can conduct direct teleoperation with 3D graphic prediction simulation established by the VR technique. In order to remove inconsistencies between the virtual and real environments, a practical model-matching method is investigated. On the other hand, to realize real-time visual servoing control, a particular object recognition and pose estimation algorithm based on polygonal approximation is investigated to ensure a low computational cost for image processing. To avoid undesired forces involved in contact operation, 3D visual servoing incorporating a compliant control based on impedance control is developed. Finally, in a representative laboratory environment, a typical satellite servicing experiment is carried out based on this combined system. Experimental results demonstrate the feasibility and the effectiveness of the proposed method.

Single Tree Vegetation Depth Estimation Tool for Satellite Services Link Design

Directory of Open Access Journals (Sweden)

Z. Hasirci

2016-04-01

Full Text Available Attenuation caused by tree shadowing is an important factor for describing the propagation channel of satellite services. Thus, vegetation effects should be determined by experimental studies or empirical formulations. In this study, tree types in the Black Sea Region of Turkey are classified based on their geometrical shapes into four groups such as conic, ellipsoid, spherical and hemispherical. The variations of the vegetation depth according to different tree shapes are calculated with ray tracing method. It is showed that different geometrical shapes have different vegetation depths even if they have same foliage volume for different elevation angles. The proposed method is validated with the related literature in terms of average single tree attenuation. On the other hand, due to decrease system requirements (speed, memory usage etc. of ray tracing method, an artificial neural network is proposed as an alternative. A graphical user interface is created for the above processes in MATLAB environment named vegetation depth estimation tool (VdET.

Mission studies on constellation of LEO satellites with remote-sensing and communication payloads

Science.gov (United States)

Chen, Chia-Ray; Hwang, Feng-Tai; Hsueh, Chuang-Wei

2017-09-01

Revisiting time and global coverage are two major requirements for most of the remote sensing satellites. Constellation of satellites can get the benefit of short revisit time and global coverage. Typically, remote sensing satellites prefer to choose Sun Synchronous Orbit (SSO) because of fixed revisiting time and Sun beta angle. The system design and mission operation will be simple and straightforward. However, if we focus on providing remote sensing and store-and-forward communication services for low latitude countries, Sun Synchronous Orbit will not be the best choice because we need more satellites to cover the communication service gap in low latitude region. Sometimes the design drivers for remote sensing payloads are conflicted with the communication payloads. For example, lower orbit altitude is better for remote sensing payload performance, but the communication service zone will be smaller and we need more satellites to provide all time communication service. The current studies focus on how to provide remote sensing and communication services for low latitude countries. A cost effective approach for the mission, i.e. constellation of microsatellites, will be evaluated in this paper.

New applications for the EUTELTRACS service

Science.gov (United States)

Colcy, Jean-Noel; Vanderbrouck, Laurent

1995-01-01

The EUTELTRACS two-way Mobile Satellite Messaging and Automatic Satellite Position Reporting (ASPR) service is Europe's first commercially operated Mobile Satellite Service. It was introduced by the European Telecommunications Satellite Organization (EUTELSAT) for commercial service in 1991. The system is based on a centralized network architecture organized around a single hub station operated by EUTELSAT. Initially the system was designed with a close user group architecture enabling a mobile user to communicate exclusively with its own headquarters. This paper describes the new applications (design and tests prior to their introduction into service) especially developed for the European market and particularly the Double Hop Services opening the system to authorized external entities. In addition, the European Commission (EC) pilot demonstrations in which the EUTELTRACS system is involved are described.

Addressing and Presenting Quality of Satellite Data via Web-Based Services

Science.gov (United States)

Leptoukh, Gregory; Lynnes, C.; Ahmad, S.; Fox, P.; Zednik, S.; West, P.

2011-01-01

With the recent attention to climate change and proliferation of remote-sensing data utilization, climate model and various environmental monitoring and protection applications have begun to increasingly rely on satellite measurements. Research application users seek good quality satellite data, with uncertainties and biases provided for each data point. However, different communities address remote sensing quality issues rather inconsistently and differently. We describe our attempt to systematically characterize, capture, and provision quality and uncertainty information as it applies to the NASA MODIS Aerosol Optical Depth data product. In particular, we note the semantic differences in quality/bias/uncertainty at the pixel, granule, product, and record levels. We outline various factors contributing to uncertainty or error budget; errors. Web-based science analysis and processing tools allow users to access, analyze, and generate visualizations of data while alleviating users from having directly managing complex data processing operations. These tools provide value by streamlining the data analysis process, but usually shield users from details of the data processing steps, algorithm assumptions, caveats, etc. Correct interpretation of the final analysis requires user understanding of how data has been generated and processed and what potential biases, anomalies, or errors may have been introduced. By providing services that leverage data lineage provenance and domain-expertise, expert systems can be built to aid the user in understanding data sources, processing, and the suitability for use of products generated by the tools. We describe our experiences developing a semantic, provenance-aware, expert-knowledge advisory system applied to NASA Giovanni web-based Earth science data analysis tool as part of the ESTO AIST-funded Multi-sensor Data Synergy Advisor project.

Advances in the application of remote sensing and GIS for surveying mountainous land

NARCIS (Netherlands)

Mulders, M.A.

2001-01-01

Satellite remote sensing has been practised since 1972, starting with broad channels and moderate ground resolution (Landsat MSS). In the 1980s, Landsat TM and SPOT provided for improved spatial and spectral resolutions. Many satellite images were produced in these two decades, offering a synoptic

Integration of speckle de-noising and image segmentation using ...

Indian Academy of Sciences (India)

2Department of Electronics and Communication Engineering, National Institute of Technology Karnataka,. Surathkal, Mangalore 575 025, India. ... cal images obtained from the satellites are often prone to bad climatic conditions and hence ... (2009) for satellite image segmentation. Mean shift segmentation (MSS) is a non-.

The design of an ultra-low sidelobe offset-fed 1.22m antenna for use in the broadcasting satellite service

Science.gov (United States)

Janky, J. M.

1981-01-01

A feed design and reflector geometry were determined for an ultra low sidelobe offset fed 1.22 meter antenna suitable for use in the 12 GHz broadcasting satellite service. Arbitrary constraints used to evaluate the relative merits of the feed horns and range of f/D geometries are: minimum efficiency of 55 percent, -30 dB first sidelobe level (relative to on axis gain), a 0 dBi plateau beyond the near in sidelobe region, and a Chebyshev polynomial based envelope (borrowed from filter theory) for the region from the -3 dB beamwidth points to the 0 dBi plateau region. This envelope is extremely stringent but the results of this research effort indicate that two steps of corrugated feed and a cluster array of small 1 lambda horns do meet the constraints. A set of performance specifications and a mechanical design suitable for a consumer oriented market in the broadcasting satellite service was developed. Costs for production quantities of 10,000 units/yr. are estimated to be around $150.

Traffic Agents for Improving QoS in Mixed Infrastructure and Ad Hoc Modes Wireless LAN

Directory of Open Access Journals (Sweden)

Yuan Hai-Feng

2006-01-01

Full Text Available As an important complement to infrastructured wireless networks, mobile ad hoc networks (MANET are more flexible in providing wireless access services, but more difficult in meeting different quality of service (QoS requirements for mobile customers. Both infrastructure and ad hoc network structures are supported in wireless local area networks (WLAN, which can offer high data-rate wireless multimedia services to the mobile stations (MSs in a limited geographical area. For those out-of-coverage MSs, how to effectively connect them to the access point (AP and provide QoS support is a challenging issue. By mixing the infrastructure and the ad hoc modes in WLAN, we propose in this paper a new coverage improvement scheme that can identify suitable idle MSs in good service zones as traffic agents (TAs to relay traffic from those out-of-coverage MSs to the AP. The service coverage area of WLAN is then expanded. The QoS requirements (e.g., bandwidth of those MSs are considered in the selection process of corresponding TAs. Mathematical analysis, verified by computer simulations, shows that the proposed TA scheme can effectively reduce blocking probability when traffic load is light.

On-board processing for telecommunications satellites

Science.gov (United States)

Nuspl, P. P.; Dong, G.

1991-01-01

In this decade, communications satellite systems will probably face dramatic challenges from alternative transmission means. To balance and overcome such competition, and to prepare for new requirements, INTELSAT has developed several on-board processing techniques, including Satellite-Switched TDMA (SS-TDMA), Satellite-Switched FDMA (SS-FDMA), several Modulators/Demodulators (Modem), a Multicarrier Multiplexer and Demodulator MCDD), an International Business Service (IBS)/Intermediate Data Rate (IDR) BaseBand Processor (BBP), etc. Some proof-of-concept hardware and software were developed, and tested recently in the INTELSAT Technical Laboratories. These techniques and some test results are discussed.

ARTES: the future of satellite telecommunication

Science.gov (United States)

González-Blázquez, Angel; Detain, Dominique

2005-08-01

Throughout its 30-year existence, ESA has played a key role by providing telecommunications infrastructures that have allowed the in-orbit validation, qualification and demonstration of equipment, technology and services. In the past, this has been achieved through the provision of dedicated satellites like OTS, Marecs, Olympus and Artemis, as well as by the implementation of piggy-back payloads on other ESA or commercial satellites. Today, due to the importance of satellite telecommunications, ESA continues to support this sector mainly through its ARTES - Advanced Research in Telecommunications - Programme.

Proceedings of the Fifth International Mobile Satellite Conference 1997

Science.gov (United States)

Jedrey, T. (Compiler); Rigley, J. (Compiler); Anderson, Louise (Editor)

1997-01-01

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments.

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.

Satellite communications - Intelsat and global patterns

Science.gov (United States)

Astrain, S.

1983-10-01

The global pattern of mankind's population growth is examined, taking into account the exponential increase in population which began only in the 17th century. As world population has grown, trade has increased, and transportation and communications have become vitally important. A revolution in global communications was initiated when Intelsat launched the first international communications satellite, 'Early Bird', in April 1965. Since April 1965, a tremendous development in global communications by means of satellites has taken place. The Intelsat VI satellite will have a capacity of 36,000 telephone circuits plus 2 TV channels, while the capacity of Early Bird was only 240 telephone circuits. Today, Intelsat is truly an international organization which includes 108 member countries. Attention is given to the particular importance of the Intelsat services to the developing countries, the exploration of new technologies and system concepts, and the extension of services to those portions of the global village which have remained electronically isolated.

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

Satellite ATM Networks: Architectures and Guidelines Developed

Science.gov (United States)

vonDeak, Thomas C.; Yegendu, Ferit

1999-01-01

An important element of satellite-supported asynchronous transfer mode (ATM) networking will involve support for the routing and rerouting of active connections. Work published under the auspices of the Telecommunications Industry Association (http://www.tiaonline.org), describes basic architectures and routing protocol issues for satellite ATM (SATATM) networks. The architectures and issues identified will serve as a basis for further development of technical specifications for these SATATM networks. Three ATM network architectures for bent pipe satellites and three ATM network architectures for satellites with onboard ATM switches were developed. The architectures differ from one another in terms of required level of mobility, supported data rates, supported terrestrial interfaces, and onboard processing and switching requirements. The documentation addresses low-, middle-, and geosynchronous-Earth-orbit satellite configurations. The satellite environment may require real-time routing to support the mobility of end devices and nodes of the ATM network itself. This requires the network to be able to reroute active circuits in real time. In addition to supporting mobility, rerouting can also be used to (1) optimize network routing, (2) respond to changing quality-of-service requirements, and (3) provide a fault tolerance mechanism. Traffic management and control functions are necessary in ATM to ensure that the quality-of-service requirements associated with each connection are not violated and also to provide flow and congestion control functions. Functions related to traffic management were identified and described. Most of these traffic management functions will be supported by on-ground ATM switches, but in a hybrid terrestrial-satellite ATM network, some of the traffic management functions may have to be supported by the onboard satellite ATM switch. Future work is planned to examine the tradeoffs of placing traffic management functions onboard a satellite as

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

Building technological capability within satellite programs in developing countries

Science.gov (United States)

Wood, Danielle; Weigel, Annalisa

2011-12-01

This paper explores the process of building technological capability in government-led satellite programs within developing countries. The key message is that these satellite programs can learn useful lessons from literature in the international development community. These lessons are relevant to emerging satellite programs that leverage international partnerships in order to establish local capability to design, build and operate satellites. Countries with such programs include Algeria, Nigeria, Turkey, Malaysia and the United Arab Emirates. The paper first provides background knowledge about space activity in developing countries, and then explores the nuances of the lessons coming from the international development literature. Developing countries are concerned with satellite technology because satellites provide useful services in the areas of earth observation, communication, navigation and science. Most developing countries access satellite services through indirect means such as sharing data with foreign organizations. More countries, however, are seeking opportunities to develop satellite technology locally. There are objective, technically driven motivations for developing countries to invest in satellite technology, despite rich debate on this topic. The paper provides a framework to understand technical motivations for investment in satellite services, hardware, expertise and infrastructure in both short and long term. If a country decides to pursue such investments they face a common set of strategic decisions at the levels of their satellite program, their national context and their international relationships. Analysis of past projects shows that countries have chosen diverse strategies to address these strategic decisions and grow in technological capability. What is similar about the historical examples is that many countries choose to leverage international partnerships as part of their growth process. There are also historical examples from

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.

A 0.7V 7-to-10bit 0-to-2MS/s Flexible SAR ADC for Ultra Low-Power Wireless Sensor Nodes

NARCIS (Netherlands)

Harpe, P.J.A.; Dolmans, G.; Philips, K.J.P.; Groot, de H.W.H.

2012-01-01

This paper presents a flexible SAR ADC in 90nm CMOS for wireless sensor nodes. By supporting resolutions from 7 to 10bit and sample rates from DC to 2MS/s, this design can be used for a variety of applications such as sensor interfacing and receiver frontends. Flexibility is achieved by a

Time-Zone-Pattern Satellite Broadcasting Antenna

Science.gov (United States)

Galindo, Victor; Rahmat-Samii, Yahya; Imbriale, William A.; Cohen, Herb; Cagnon, Ronald R.

1988-01-01

Direct-broadcast satellite antenna designs provide contoured beams to match four time zones in 48 contiguous states and spot beams for Alaska, Hawaii, and Puerto Rico presented in 29-page report. Includes descriptions of procedures used to arrive at optimized designs. Arrangements, amplitudes, and phases of antenna feeds presented in tables. Gain contours shown graphically. Additional tables of performance data given for cities in service area of Eastern satellite.

A 10 bit 200 MS/s pipeline ADC using loading-balanced architecture in 0.18 μm CMOS

Science.gov (United States)

Wang, Linfeng; Meng, Qiao; Zhi, Hao; Li, Fei

2017-07-01

A new loading-balanced architecture for high speed and low power consumption pipeline analog-to-digital converter (ADC) is presented in this paper. The proposed ADC uses SHA-less, op-amp and capacitor-sharing technique, capacitor-scaling scheme to reduce the die area and power consumption. A new capacitor-sharing scheme was proposed to cancel the extra reset phase of the feedback capacitors. The non-standard inter-stage gain increases the feedback factor of the first stage and makes it equal to the second stage, by which, the load capacitor of op-amp shared by the first and second stages is balanced. As for the fourth stage, the capacitor and op-amp no longer scale down. From the system’s point of view, all load capacitors of the shared OTAs are balanced by employing a loading-balanced architecture. The die area and power consumption are optimized maximally. The ADC is implemented in a 0.18 μm 1P6M CMOS technology, and occupies a die area of 1.2 × 1.2 mm{}2. The measurement results show a 55.58 dB signal-to-noise-and-distortion ratio (SNDR) and 62.97 dB spurious-free dynamic range (SFDR) with a 25 MHz input operating at a 200 MS/s sampling rate. The proposed ADC consumes 115 mW at 200 MS/s from a 1.8 V supply.

Satellites for U.S. education - Needs, opportunities and systems.

Science.gov (United States)

Morgan, R. P.; Singh, J. P.; Anderson, B. D.; Greenberg, E.

1972-01-01

This paper presents results of a continuing interdisciplinary study of the potential applications of Fixed- and Broadcast-Satellites for educational information transfer in the United States for the period 1975-1985. The status of U.S. education is examined and needs, trends and issues are discussed. The existing educational telecommunications infrastructure is examined and opportunities for satellite services are defined. Potential uses include networking of educational institutions and service centers for delivery of public and instructional television, computer-aided instruction, computing and information resources to regions and groups not now adequately served. Systems alternatives and some of the organizational and economic issues inherent in the deployment of an educational satellite system are discussed.-

Summary of Current Radiometric Calibration Coefficients for Landsat MSS, TM, ETM+, and EO-1 ALI Sensors

Science.gov (United States)

Chander, Gyanesh; Markham, Brian L.; Helder, Dennis L.

2009-01-01

This paper provides a summary of the current equations and rescaling factors for converting calibrated Digital Numbers (DNs) to absolute units of at-sensor spectral radiance, Top-Of- Atmosphere (TOA) reflectance, and at-sensor brightness temperature. It tabulates the necessary constants for the Multispectral Scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), and Advanced Land Imager (ALI) sensors. These conversions provide a basis for standardized comparison of data in a single scene or between images acquired on different dates or by different sensors. This paper forms a needed guide for Landsat data users who now have access to the entire Landsat archive at no cost.

A radiation-hard dual-channel 12-bit 40 MS/s ADC prototype for the ATLAS liquid argon calorimeter readout electronics upgrade at the CERN LHC

Energy Technology Data Exchange (ETDEWEB)

Kuppambatti, J. [Columbia University, Dept. of Electrical Engineering, New York, NY (United States); Ban, J. [Columbia University, Nevis Laboratories, Irvington, NY (United States); Andeen, T., E-mail: tandeen@utexas.edu [Columbia University, Nevis Laboratories, Irvington, NY (United States); Brown, R.; Carbone, R. [Columbia University, Nevis Laboratories, Irvington, NY (United States); Kinget, P. [Columbia University, Dept. of Electrical Engineering, New York, NY (United States); Brooijmans, G.; Sippach, W. [Columbia University, Nevis Laboratories, Irvington, NY (United States)

2017-05-21

The readout electronics upgrade for the ATLAS Liquid Argon Calorimeters at the CERN Large Hadron Collider requires a radiation-hard ADC. The design of a radiation-hard dual-channel 12-bit 40 MS/s pipeline ADC for this use is presented. The design consists of two pipeline A/D channels each with four Multiplying Digital-to-Analog Converters followed by 8-bit Successive-Approximation-Register analog-to-digital converters. The custom design, fabricated in a commercial 130 nm CMOS process, shows a performance of 67.9 dB SNDR at 10 MHz for a single channel at 40 MS/s, with a latency of 87.5 ns (to first bit read out), while its total power consumption is 50 mW/channel. The chip uses two power supply voltages: 1.2 and 2.5 V. The sensitivity to single event effects during irradiation is measured and determined to meet the system requirements.

A demand assignment control in international business satellite communications network

Science.gov (United States)

Nohara, Mitsuo; Takeuchi, Yoshio; Takahata, Fumio; Hirata, Yasuo

An experimental system is being developed for use in an international business satellite (IBS) communications network based on demand-assignment (DA) and TDMA techniques. This paper discusses its system design, in particular from the viewpoints of a network configuration, a DA control, and a satellite channel-assignment algorithm. A satellite channel configuration is also presented along with a tradeoff study on transmission rate, HPA output power, satellite resource efficiency, service quality, and so on.

A design of 30/20 GHz flight communications experiment for NASA. [satellite and earth segments for high data rate commercial service

Science.gov (United States)

Kawamoto, Y.

1982-01-01

The objective of the 30/20 GHz Flight Experiment System is to develop the required technology and to experiment with the communication technique for an operational communication satellite system. The system uses polarization, spatial, and frequency isolations to maximize the spectrum utilization. The key spacecraft technologies required for the concept are the scan beam antenna, the baseband processor, the IF switch matrix, TWTA, SSPA, and LNA. The spacecraft communication payload information will be telemetered and monitored closely so that these technologies and performances can be verified. Two types of services, a trunk service and a customer premise service, are demonstrated in the system. Many experiments associated with these services, such as synchronization, demand assignment, link control, and network control will be performed to provide important information on the operational aspect of the system.

Protocols for second-generation business satellites systems

Science.gov (United States)

Evans, B. G.; Coakley, F. P.; El Amin, M. H. M.

The paper discusses the nature and mix of traffic in business satellite systems and describes the limitations on the protocol imposed by the differing impairments of speech, video, and data. A simple TDMA system protocol is presented which meets the requirements of mixed-service operation. The efficiency of the protocol together with implications for allocation, scheduling and synchronisation are discussed. Future-generation satellites will probably use on-board processing. Some initial work on protocols that make use of on-board processing and the implications for satellite and earth-station equipment are presented.

Challenges in Visualizing Satellite Level 2 Atmospheric Data with GIS approach

Science.gov (United States)

Wei, J. C.; Yang, W.; Zhao, P.; Pham, L.; Meyer, D. J.

2017-12-01

Satellite data products are important for a wide variety of applications that can bring far-reaching benefits to the science community and the broader society. These benefits can best be achieved if the satellite data are well utilized and interpreted. Unfortunately, this is not always the case, despite the abundance and relative maturity of numerous satellite data products provided by NASA and other organizations. One way to help users better understand the satellite data is to provide data along with `Images', including accurate pixel coverage area delineation, and science team recommended quality screening for individual geophysical parameters. However, there are challenges of visualizing remote sensed non-gridded products: (1) different geodetics of space-borne instruments (2) data often arranged in "along-track" and "across-track" axes (3) spatially and temporally continuous data chunked into granule files: data for a portion (or all) of a satellite orbit (4) no general rule of resampling or interpolations to a grid (5) geophysical retrieval only based on pixel center location without shape information. In this presentation, we will unravel a new Goddard Earth Sciences Data and Information Services Center (GES DISC) Level 2 (L2) visualization on-demand service. The service's front end provides various visualization and data accessing capabilities, such as overlay and swipe of multiply variables and subset and download of data in different formats. The backend of the service consists of Open Geospatial Consortium (OGC) standard-compliant Web Mapping Service (WMS) and Web Coverage Service. The infrastructure allows inclusion of outside data sources served in OGC compliant protocols and allows other interoperable clients, such as ArcGIS clients, to connect to our L2 WCS/WMS.

Challenges in Obtaining and Visualizing Satellite Level 2 Data in GIS

Science.gov (United States)

Wei, Jennifer C.; Yang, Wenli; Zhao, Peisheng; Pham, Long; Meyer, David J.

2017-01-01

Satellite data products are important for a wide variety of applications that can bring far-reaching benefits to the science community and the broader society. These benefits can best be achieved if the satellite data are well utilized and interpreted. Unfortunately, this is not always the case, despite the abundance and relative maturity of numerous satellite data products provided by NASA and other organizations. One way to help users better understand the satellite data is to provide data along with Images, including accurate pixel coverage area delineation, and science team recommended quality screening for individual geophysical parameters. However, there are challenges of visualizing remote sensed non-gridded products: (1) different geodetics of space-borne instruments (2) data often arranged in a long-track� and a cross-track� axes (3) spatially and temporally continuous data chunked into granule files: data for a portion (or all) of a satellite orbit (4) no general rule of resampling or interpolations to a grid (5) geophysical retrieval only based on pixel center location without shape information. In this presentation, we will unravel a new Goddard Earth Sciences Data and Information Services Center (GES DISC) Level 2 (L2) visualization on-demand service. The service's front end provides various visualization and data accessing capabilities, such as overlay and swipe of multiply variables and subset and download of data in different formats. The backend of the service consists of Open Geospatial Consortium (OGC) standard-compliant Web Mapping Service (WMS) and Web Coverage Service. The infrastructure allows inclusion of outside data sources served in OGC compliant protocols and allows other interoperable clients, such as ArcGIS clients, to connect to our L2 WCS/WMS.

An Attempt to automate the lithological classification of rocks using geological, gamma-spectrometric and satellite image datasets

International Nuclear Information System (INIS)

Fouad, M. K.; Mielik, M. L.; Gharieb, A. N.

2004-01-01

The present study aims essentially at proving that the application of the integrated airborne gamma spectrometric and satellite image data is capable of refining the mapped surface geology, and identification of anomalous zones of radioelement content that could provide favorable exploration targets for radioactive mineralizations.The application of the appropriate statistical technique to correlate between satellite image data and gamma-spectrometric data is of great significance in this respect. Experience shows that Landsat T M data in 7 spectral bands are successfully used in such studies rather than MSS. Multivariate statistical analysis techniques are applied to airborne spectrometric and different spectral Landsat T M data. Reduction of the data from n-dimensionality, both qualitatively as color composite image, and quantitatively, as principal component analysis, is performed using some statistical control parameters. This technique shows distinct efficiency in defining areas where different lit ho facies occur. An area located at the north of the Eastern Desert of Egypt, north of Hurgada town, was chosen to test the proposed technique of integrated interpretation of data of different physical nature. The reduced data are represented and interpreted both qualitatively and quantitatively. The advantages and limitations of applying such technique to the different airborne spectrometric, and Landsat T M data are identified. (authors)

A 14-bit 50 MS/s sample-and-hold circuit for pipelined ADC

International Nuclear Information System (INIS)

Yue Sen; Zhao Yiqiang; Pang Ruilong; Sheng Yun

2014-01-01

A high performance sample-and-hold (S/H) circuit used in a pipelined analog-to-digital converter (ADC) is presented. Capacitor flip-around architecture is used in this S/H circuit with a novel gain-boosted differential folded cascode operational transconductance amplifier. A double-bootstrapped switch is designed to improve the performance of the circuit. The circuit is implemented using a 0.18 μm 1P6M CMOS process. Measurement results show that the effective number of bits is 14.03 bits, the spurious free dynamic range is 94.62 dB, the signal to noise and distortion ratio is 86.28 dB, and the total harmonic distortion is −91:84 dB for a 5 MHz input signal with 50 MS/s sampling rate. A pipeline ADC with the designed S/H circuit has been implemented. (semiconductor integrated circuits)

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.

Increasing cellular coverage within integrated terrestrial/satellite mobile networks

Science.gov (United States)

Castro, Jonathan P.

1995-01-01

When applying the hierarchical cellular concept, the satellite acts as giant umbrella cell covering a region with some terrestrial cells. If a mobile terminal traversing the region arrives to the border-line or limits of a regular cellular ground service, network transition occurs and the satellite system continues the mobile coverage. To adequately assess the boundaries of service of a mobile satellite system an a cellular network within an integrated environment, this paper provides an optimized scheme to predict when a network transition may be necessary. Under the assumption of a classified propagation phenomenon and Lognormal shadowing, the study applies an analytical approach to estimate the location of a mobile terminal based on a reception of the signal strength emitted by a base station.

Environmental Impact Statement. Small Intercontinental Ballistic Missile Program. Malmstrom Air Force Base, Montana

Science.gov (United States)

1987-12-01

Homestead Cordova Grain Elevator Dinkes Farmstead Bremmer Farmstead Alzheimer Farmstead H. Schwert Homestead Notes: 1National Historic Landmark...Butte. Earth Satellite Corporation 1974a Geopic: Earth Resources Observations Systems, MSS 5 Scene 10806-17235 N46-01 W108-47 P040 R28. Landsat 4...coverage: scale 1:500,000. Billings, Montana. 1974b Geopic: Earth Resources Observation Systems, MSS 5 Scene 10790-17352 N47-19 W111-06 P042 R27. Landsat 4

Integration of the Mini-Sulfide Sulfite Anthraquinone (MSS-AQ) Pulping Process and Black Liquor Gasification in a Pulp Mill

Energy Technology Data Exchange (ETDEWEB)

Hasan Jameel, North Carolina State University; Adrianna Kirkman, North Carolina State University; Ravi Chandran,Thermochem Recovery International Brian Turk Research Triangle Institute; Brian Green, Research Triangle Institute

2010-01-27

As many of the recovery boilers and other pieces of large capital equipment of U.S. pulp mills are nearing the end of their useful life, the pulp and paper industry will soon need to make long-term investments in new technologies. The ability to install integrated, complete systems that are highly efficient will impact the industry’s energy use for decades to come. Developing a process for these new systems is key to the adoption of state-of-the-art technologies in the Forest Products industry. This project defined an integrated process model that combines mini-sulfide sulfite anthraquinone (MSS-AQ) pulping and black liquor gasification with a proprietary desulfurization process developed by the Research Triangle Institute. Black liquor gasification is an emerging technology that enables the use of MSS-AQ pulping, which results in higher yield, lower bleaching cost, lower sulfur emissions, and the elimination of causticization requirements. The recently developed gas cleanup/absorber technology can clean the product gas to a state suitable for use in a gas turbine and also regenerate the pulping chemicals needed to for the MSS-AQ pulping process. The combination of three advanced technologies into an integrated design will enable the pulping industry to achieve a new level of efficiency, environmental performance, and cost savings. Because the three technologies are complimentary, their adoption as a streamlined package will ensure their ability to deliver maximum energy and cost savings benefits. The process models developed by this project will enable the successful integration of new technologies into the next generation of chemical pulping mills. When compared to the Kraft reference pulp, the MSS-AQ procedures produced pulps with a 10-15 % yield benefit and the ISO brightness was 1.5-2 times greater. The pulp refined little easier and had a slightly lower apparent sheet density (In both the cases). At similar levels of tear index the MSS-AQ pulps also

Charter for Systems Engineer Working Group

Science.gov (United States)

Suffredini, Michael T.; Grissom, Larry

2015-01-01

This charter establishes the International Space Station Program (ISSP) Mobile Servicing System (MSS) Systems Engineering Working Group (SEWG). The MSS SEWG is established to provide a mechanism for Systems Engineering for the end-to-end MSS function. The MSS end-to-end function includes the Space Station Remote Manipulator System (SSRMS), the Mobile Remote Servicer (MRS) Base System (MBS), Robotic Work Station (RWS), Special Purpose Dexterous Manipulator (SPDM), Video Signal Converters (VSC), and Operations Control Software (OCS), the Mobile Transporter (MT), and by interfaces between and among these elements, and United States On-Orbit Segment (USOS) distributed systems, and other International Space Station Elements and Payloads, (including the Power Data Grapple Fixtures (PDGFs), MSS Capture Attach System (MCAS) and the Mobile Transporter Capture Latch (MTCL)). This end-to-end function will be supported by the ISS and MSS ground segment facilities. This charter defines the scope and limits of the program authority and document control that is delegated to the SEWG and it also identifies the panel core membership and specific operating policies.

Ground Simulation of an Autonomous Satellite Rendezvous and Tracking System Using Dual Robotic Systems

Science.gov (United States)

Trube, Matthew J.; Hyslop, Andrew M.; Carignan, Craig R.; Easley, Joseph W.

2012-01-01

A hardware-in-the-loop ground system was developed for simulating a robotic servicer spacecraft tracking a target satellite at short range. A relative navigation sensor package "Argon" is mounted on the end-effector of a Fanuc 430 manipulator, which functions as the base platform of the robotic spacecraft servicer. Machine vision algorithms estimate the pose of the target spacecraft, mounted on a Rotopod R-2000 platform, relay the solution to a simulation of the servicer spacecraft running in "Freespace", which performs guidance, navigation and control functions, integrates dynamics, and issues motion commands to a Fanuc platform controller so that it tracks the simulated servicer spacecraft. Results will be reviewed for several satellite motion scenarios at different ranges. Key words: robotics, satellite, servicing, guidance, navigation, tracking, control, docking.

An overview of reference user services during the ATDRSS (Advanced Tracking and Data Relay Satellite System) era

Science.gov (United States)

Weinberg, Aaron

1989-01-01

The Tracking and Data Relay Satellite System (TDRSS) is an integral part of the overall NASA Space Network (SN) that will continue to evolve into the 1990's. Projections for the first decade of the 21st century indicate the need for an SN evolution that must accommodate growth int he LEO user population and must further support the introduction of new/improved user services. A central ingredient of this evolution is an Advanced TDRSS (ATDRSS) follow-on to the current TDRSS that must initiate operations by the late 1990's in a manner that permits an orderly transition from the TDRSS to the ATDRSS era. An SN/ATDRSS architectural and operational concept that will satisfy the above goals is being developed. To this date, an SN/ATDRSS baseline concept was established that provides users with an end-to-end data transport (ENDAT) service. An expanded description of the baseline ENDAT concept, from the user perspective, is provided with special emphasis on the TDRSS/ATDRSS evolution. A high-level description of the end-to-end system that identifies the role of ATDRSS is presented; also included is a description of the baseline ATDRSS architecture and its relationship with the TDRSS 1996 baseline. Other key features of the ENDAT service are then expanded upon, including the multiple grades of service, and the RF telecommunications/tracking services to be available. The ATDRSS service options are described.

A 12-bit 40 MS/s pipelined ADC with over 80 dB SFDR

Energy Technology Data Exchange (ETDEWEB)

Wei Qi; Yin Xiumei; Han Dandan; Yang Huazhong, E-mail: q-wei05@mails.tsinghua.edu.c [Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China)

2010-02-15

This paper describes a 12-bit 40 MS/s calibration-free pipelined analog-to-digital converter (ADC), which is optimized for high spurious free dynamic range (SFDR) performance and low power dissipation. With a 4.9 MHz sine wave input, the prototype ADC implemented in a 0.18-{mu}m 1P6M CMOS process shows measured differential nonlinearity and integral nonlinearity within 0.78 and 1.32 least significant bits at the 12-bit level without any trimming or calibration. The ADC, with a total die area of 3.1 x 2.1 mm{sup 2}, demonstrates a maximum signal-to-noise distortion ratio (SNDR) and SFDR of 66.32 and 83.38 dB, respectively, at a 4.9 MHz analog input and a power consumption of 102 mW from a 1.8 V supply. (semiconductor integrated circuits)

COSMOS Launch Services

Science.gov (United States)

Kalnins, Indulis

2002-01-01

COSMOS-3M is a two stage launcher with liquid propellant rocket engines. Since 1960's COSMOS has launched satellites of up to 1.500kg in both circular low Earth and elliptical orbits with high inclination. The direct SSO ascent is available from Plesetsk launch site. The very high number of 759 launches and the achieved success rate of 97,4% makes this space transportation system one of the most reliable and successful launchers in the world. The German small satellite company OHB System co-operates since 1994 with the COSMOS manufacturer POLYOT, Omsk, in Russia. They have created the joint venture COSMOS International and successfully launched five German and Italian satellites in 1999 and 2000. The next commercial launches are contracted for 2002 and 2003. In 2005 -2007 COSMOS will be also used for the new German reconnaissance satellite launches. This paper provides an overview of COSMOS-3M launcher: its heritage and performance, examples of scientific and commercial primary and piggyback payload launches, the launch service organization and international cooperation. The COSMOS launch service business strategy main points are depicted. The current and future position of COSMOS in the worldwide market of launch services is outlined.

How to Get Data from NOAA Environmental Satellites: An Overview of Operations, Products, Access and Archive

Science.gov (United States)

Donoho, N.; Graumann, A.; McNamara, D. P.

2015-12-01

In this presentation we will highlight access and availability of NOAA satellite data for near real time (NRT) and retrospective product users. The presentation includes an overview of the current fleet of NOAA satellites and methods of data distribution and access to hundreds of imagery and products offered by the Environmental Satellite Processing Center (ESPC) and the Comprehensive Large Array-data Stewardship System (CLASS). In particular, emphasis on the various levels of services for current and past observations will be presented. The National Environmental Satellite, Data, and Information Service (NESDIS) is dedicated to providing timely access to global environmental data from satellites and other sources. In special cases, users are authorized direct access to NESDIS data distribution systems for environmental satellite data and products. Other means of access include publicly available distribution services such as the Global Telecommunication System (GTS), NOAA satellite direct broadcast services and various NOAA websites and ftp servers, including CLASS. CLASS is NOAA's information technology system designed to support long-term, secure preservation and standards-based access to environmental data collections and information. The National Centers for Environmental Information (NCEI) is responsible for the ingest, quality control, stewardship, archival and access to data and science information. This work will also show the latest technology improvements, enterprise approach and future plans for distribution of exponentially increasing data volumes from future NOAA missions. A primer on access to NOAA operational satellite products and services is available at http://www.ospo.noaa.gov/Organization/About/access.html. Access to post-operational satellite data and assorted products is available at http://www.class.noaa.gov

Application of remote sensing methods for detection of water pollution degree in rivers and water reservoirs

International Nuclear Information System (INIS)

Krzyworzeka, M.; Piasek, Z.

1997-01-01

The paper presents non-contact registration methods of the electromagnetic radiation which can be used for the detection of water pollution in rivers and water reservoirs. These methods include aerial photographs, satellite images and thermograms. The satellite images need reprocessing to obtain the mutual comparability of the images from various multispectral scanners (TM and MSS)

An IP-oriented 11-bit 160 MS/s 2-channel current-steering DAC

International Nuclear Information System (INIS)

Xu Ning; Li Fule; Zhang Chun; Wang Zhihua

2014-01-01

This paper presents an 11-bit 160 MS/s 2-channel current-steering digital-to-analog converter (DAC) IP. The circuit and layout are carefully designed to optimize its performance and area. A 6-2-3 segmented structure is used for the trade-off among linearity, area and layout complexity. The sizes of current source transistors are calculated out according to the process matching parameter. The unary current cells are placed in a one-dimension distribution to simplify the layout routing, spare area and wiring layer. Their sequences are also carefully designed to reduce integral nonlinearity. The test result presents an SFDR of 72 dBc at 4.88 MHz input signal with DNL ⩽ 0.25 LSB, INL ⩽ 0.8 LSB. The full-scale output current is 5 mA with a 2.5 V analog power supply. The core of each channel occupies 0.08 mm 2 in a 1P-8M 55 nm CMOS process. (semiconductor integrated circuits)

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.”

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.

Planned Products of the Mars Structure Service for the InSight Mission to Mars

Science.gov (United States)

Panning, Mark P.; Lognonné, Philippe; Bruce Banerdt, W.; Garcia, Raphaël; Golombek, Matthew; Kedar, Sharon; Knapmeyer-Endrun, Brigitte; Mocquet, Antoine; Teanby, Nick A.; Tromp, Jeroen; Weber, Renee; Beucler, Eric; Blanchette-Guertin, Jean-Francois; Bozdağ, Ebru; Drilleau, Mélanie; Gudkova, Tamara; Hempel, Stefanie; Khan, Amir; Lekić, Vedran; Murdoch, Naomi; Plesa, Ana-Catalina; Rivoldini, Atillio; Schmerr, Nicholas; Ruan, Youyi; Verhoeven, Olivier; Gao, Chao; Christensen, Ulrich; Clinton, John; Dehant, Veronique; Giardini, Domenico; Mimoun, David; Thomas Pike, W.; Smrekar, Sue; Wieczorek, Mark; Knapmeyer, Martin; Wookey, James

2017-10-01

The InSight lander will deliver geophysical instruments to Mars in 2018, including seismometers installed directly on the surface (Seismic Experiment for Interior Structure, SEIS). Routine operations will be split into two services, the Mars Structure Service (MSS) and Marsquake Service (MQS), which will be responsible, respectively, for defining the structure models and seismicity catalogs from the mission. The MSS will deliver a series of products before the landing, during the operations, and finally to the Planetary Data System (PDS) archive. Prior to the mission, we assembled a suite of a priori models of Mars, based on estimates of bulk composition and thermal profiles. Initial models during the mission will rely on modeling surface waves and impact-generated body waves independent of prior knowledge of structure. Later modeling will include simultaneous inversion of seismic observations for source and structural parameters. We use Bayesian inversion techniques to obtain robust probability distribution functions of interior structure parameters. Shallow structure will be characterized using the hammering of the heatflow probe mole, as well as measurements of surface wave ellipticity. Crustal scale structure will be constrained by measurements of receiver function and broadband Rayleigh wave ellipticity measurements. Core interacting body wave phases should be observable above modeled martian noise levels, allowing us to constrain deep structure. Normal modes of Mars should also be observable and can be used to estimate the globally averaged 1D structure, while combination with results from the InSight radio science mission and orbital observations will allow for constraint of deeper structure.

Cloud-based Web Services for Near-Real-Time Web access to NPP Satellite Imagery and other Data

Science.gov (United States)

Evans, J. D.; Valente, E. G.

2010-12-01

We are building a scalable, cloud computing-based infrastructure for Web access to near-real-time data products synthesized from the U.S. National Polar-Orbiting Environmental Satellite System (NPOESS) Preparatory Project (NPP) and other geospatial and meteorological data. Given recent and ongoing changes in the the NPP and NPOESS programs (now Joint Polar Satellite System), the need for timely delivery of NPP data is urgent. We propose an alternative to a traditional, centralized ground segment, using distributed Direct Broadcast facilities linked to industry-standard Web services by a streamlined processing chain running in a scalable cloud computing environment. Our processing chain, currently implemented on Amazon.com's Elastic Compute Cloud (EC2), retrieves raw data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and synthesizes data products such as Sea-Surface Temperature, Vegetation Indices, etc. The cloud computing approach lets us grow and shrink computing resources to meet large and rapid fluctuations (twice daily) in both end-user demand and data availability from polar-orbiting sensors. Early prototypes have delivered various data products to end-users with latencies between 6 and 32 minutes. We have begun to replicate machine instances in the cloud, so as to reduce latency and maintain near-real time data access regardless of increased data input rates or user demand -- all at quite moderate monthly costs. Our service-based approach (in which users invoke software processes on a Web-accessible server) facilitates access into datasets of arbitrary size and resolution, and allows users to request and receive tailored and composite (e.g., false-color multiband) products on demand. To facilitate broad impact and adoption of our technology, we have emphasized open, industry-standard software interfaces and open source software. Through our work, we envision the widespread establishment of similar, derived, or interoperable systems for

Texas Telecommunication Satellite Demonstration Project. Planning Effort for Application of Communication Satellites in Education.

Science.gov (United States)

Education Service Center Region 4, Houston, TX.

The primary goal of the Texas Telecommunication Satellite Demonstration consortium is to install, operate, and evaluate a comprehensive communication service delivery system which would provide the citizens of Texas with greater opportunity for equal access to education and information. The four major objectives of the demonstration are (1) to…

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

Science.gov (United States)

Texas Education Agency, Austin.

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

A Case Study of Three Satellite Technology Demonstration School Sites.

Science.gov (United States)

Law, Gordon

The Satellite Technology Demonstration (STD) represented a cooperative and complex effort involving federal, regional, state and local interests and demonstrated the feasibility of media distribution by communication satellite of social services for rural audiences. As part of a comprehensive evaluation plan, the summative data base was augmented…

47 CFR 25.217 - Default service rules.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Default service rules. 25.217 Section 25.217 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS... licenses to operate a satellite system in a frequency band granted after a domestic frequency allocation...

Study of LEO-SAT microwave link for broad-band mobile satellite communication system

Science.gov (United States)

Fujise, Masayuki; Chujo, Wataru; Chiba, Isamu; Furuhama, Yoji; Kawabata, Kazuaki; Konishi, Yoshihiko

1993-01-01

In the field of mobile satellite communications, a system based on low-earth-orbit satellites (LEO-SAT's) such as the Iridium system has been proposed. The LEO-SAT system is able to offer mobile telecommunication services in high-latitude areas. Rain degradation, fading and shadowing are also expected to be decreased when the system is operated at a high elevation angle. Furthermore, the propagation delay generated in the LEO-SAT system is less pronounced than that in the geostationary orbit satellite (GEO-SAT) system and, in voice services, the effect of the delay is almost negligible. We proposed a concept of a broad-band mobile satellite communication system with LEO-SAT's and Optical ISL. In that system, a fixed L-band (1.6/1.5 GHz) multibeam is used to offer narrow band service to the mobile terminals in the entire area covered by a LEO-SAT and steerable Ka-band (30/20 GHz) spot beams are used for the wide band service. In this paper, we present results of a study of LEO-SAT microwave link between a satellite and a mobile terminal for a broad-band mobile satellite communication system. First, the results of link budget calculations are presented and the antennas mounted on satellites are shown. For a future mobile antenna technology, we also show digital beamforming (DBF) techniques. DBF, together with modulation and/or demodulation, is becoming a key technique for mobile antennas with advanced functions such as antenna pattern calibration, correction, and radio interference suppression. In this paper, efficient DBF techniques for transmitting and receiving are presented. Furthermore, an adaptive array antenna system suitable for this LEO-SAT is presented.

Satellite Communications Using Commercial Protocols

Science.gov (United States)

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

2000-01-01

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

47 CFR 25.401 - Satellite DARS applications subject to competitive bidding.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Satellite DARS applications subject to competitive bidding. 25.401 Section 25.401 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Competitive Bidding Procedures for DARS § 25.401...

47 CFR 25.140 - Qualifications of fixed-satellite space station licensees.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Qualifications of fixed-satellite space station licensees. 25.140 Section 25.140 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space Stations § 25.140 Qualifications...

Design of a 12-bit 80-MS/s CMOS digital-to-analog converter for PLC-VDSL applications

Science.gov (United States)

Ruiz-Amaya, Jesus; Delgado-Restituto, Manuel; Fernandez-Bootello, J. Francisco; de la Rosa, Jose M.

2005-06-01

This paper describes the design of a 12-bit 80MS/s Digital-to-Analog converter implemented in 0.13mm CMOS logic technology. The design has been computer-aided by a developed toolbox for the simulation and verification of Nyquist-Rate Analog-to-Digital and Digital-to-Analog converters in MATLAB. The embedded simulator uses SIMULINK C-coded S-functions to model all required subcircuits including their main error mechanisms. This approach allows to drastically speed up the simulation CPU-time and makes the proposed tool an advantageous alternative for fast exploration of requirements and as a design validation tool. The converter is segmented in a unary current-cell matrix for 8 MSB's and a binary-weighted array for 4 LSB's. Current sources of the converter are laid out separately from current-cell switching matrix core block and distribute in double centroid to reduce random errors and transient noise coupling. The linearity errors caused by remaining gradient errors are reduced by a modified Q2 Random-Walk switching sequence. Simulation results show that the Spurious-Free Dynamic-Range is better than 58.5dB up to 80MS/s. The estimated Signal-to-Noise Distortion Ratio yield is 99.7% and it is supposed to be better than 58dB from DC to Nyquist frequency. Multi-Tone Power Ratio is higher 59dB for several DMT test signals. The converter dissipates less than 129mW from a 3.3V supply and occupies less than 1.7mm2 die area. The results have been checked with all process corners from -40° to 85° and power supply from 3V to 3.6V.

Fire Monitoring - The use of medium resolution satellites (AVHRR, MODIS, TET) for long time series processing and the implementation in User Driven Applications and Services

Science.gov (United States)

Fuchs, E.-M.; Stein, E.; Strunz, G.; Strobl, C.; Frey, C.

2015-04-01

This paper introduces fire monitoring works of two different projects, namely TIMELINE (TIMe Series Processing of Medium Resolution Earth Observation Data assessing Long -Term Dynamics In our Natural Environment) and PHAROS (Project on a Multi-Hazard Open Platform for Satellite Based Downstream Services). It describes the evolution from algorithm development from in applied research to the implementation in user driven applications and systems. Concerning TIMELINE, the focus of the work lies on hot spot detection. A detailed description of the choice of a suitable algorithm (round robin approach) will be given. Moreover, strengths and weaknesses of the AVHRR sensor for hot spot detection, a literature review, the study areas and the selected approach will be highlighted. The evaluation showed that the contextual algorithm performed best, and will therefore be used for final implementation. Concerning the PHAROS project, the key aspect is on the use of satellite-based information to provide valuable support to all phases of disaster management. The project focuses on developing a pre-operational sustainable service platform that integrates space-based EO (Earth Observation), terrestrial sensors and communication and navigation assets to enhance the availability of services and products following a multi-hazard approach.

Conical scan impact study. Volume 2: Small local user data processing facility. [multispectral band scanner design alternatives for earth resources data

Science.gov (United States)

Ebert, D. H.; Chase, P. E.; Dye, J.; Fahline, W. C.; Johnson, R. H.

1973-01-01

The impact of a conical scan versus a linear scan multispectral scanner (MSS) instrument on a small local-user data processing facility was studied. User data requirements were examined to determine the unique system rquirements for a low cost ground system (LCGS) compatible with the Earth Observatory Satellite (EOS) system. Candidate concepts were defined for the LCGS and preliminary designs were developed for selected concepts. The impact of a conical scan MSS versus a linear scan MSS was evaluated for the selected concepts. It was concluded that there are valid user requirements for the LCGS and, as a result of these requirements, the impact of the conical scanner is minimal, although some new hardware development for the LCGS is necessary to handle conical scan data.

MARAD maritime experiments using the NASA ATS-6 satellite

Science.gov (United States)

Brandel, D. L.; Kaminsky, Y.

1975-01-01

The objectives of the MARAD maritime experiments (conducted in the L-band fan beam mode) using the ATS-6 satellite are detailed. They include the following: (1) to evaluate the economic benefits of fleet operators through the use of satellite communications, (2) to evaluate performance criteria for shipboard terminal equipment needed to establish various grades of fleet operations services using commercial satellite systems, (3) to determine the effects of signal propagation, ship radio frequency noise, and ship antenna pointing on the maritime communications and navigation channel, and (4) to evaluate various modems for the transmission and reception of voice, data and position location signals via satellite systems.

A 10-bit 80-MS/s opamp-sharing pipelined ADC with a switch-embedded dual-input MDAC

Energy Technology Data Exchange (ETDEWEB)

Yin Rui; Zhang Wei; Tang Zhangwen [ASIC and System State Key Laboratory, Fudan University, Shanghai 201203 (China); Liao Youchun, E-mail: zwtang@fudan.edu.cn [Ratio Microelectronics Co., Ltd, Shanghai 200433 (China)

2011-02-15

A 10-bit 80-MS/s opamp-sharing pipelined ADC is implemented in a 0.18-{mu}m CMOS. An opamp-sharing MDAC with a switch-embedded dual-input opamp is proposed to eliminate the non-resetting and successive-stage crosstalk problems observed in the conventional opamp-sharing technique. The ADC achieves a peak SNDR of 60.1 dB (ENOB = 9.69 bits) and a peak SFDR of 76 dB, while maintaining more than 9.6 ENOB for the full Nyquist input bandwidth. The core area of the ADC is 1.1 mm{sup 2} and the chip consumes 28 mW with a 1.8 V power supply. (semiconductor integrated circuits)

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

Mean Dynamic Topography of the Arctic Ocean

Science.gov (United States)

Farrell, Sinead Louise; Mcadoo, David C.; Laxon, Seymour W.; Zwally, H. Jay; Yi, Donghui; Ridout, Andy; Giles, Katherine

2012-01-01

ICESat and Envisat altimetry data provide measurements of the instantaneous sea surface height (SSH) across the Arctic Ocean, using lead and open water elevation within the sea ice pack. First, these data were used to derive two independent mean sea surface (MSS) models by stacking and averaging along-track SSH profiles gathered between 2003 and 2009. The ICESat and Envisat MSS data were combined to construct the high-resolution ICEn MSS. Second, we estimate the 5.5-year mean dynamic topography (MDT) of the Arctic Ocean by differencing the ICEn MSS with the new GOCO02S geoid model, derived from GRACE and GOCE gravity. Using these satellite-only data we map the major features of Arctic Ocean dynamical height that are consistent with in situ observations, including the topographical highs and lows of the Beaufort and Greenland Gyres, respectively. Smaller-scale MDT structures remain largely unresolved due to uncertainties in the geoid at short wavelengths.

Experimental study on the precise orbit determination of the BeiDou navigation satellite system.

Science.gov (United States)

He, Lina; Ge, Maorong; Wang, Jiexian; Wickert, Jens; Schuh, Harald

2013-03-01

The regional service of the Chinese BeiDou satellite navigation system is now in operation with a constellation including five Geostationary Earth Orbit satellites (GEO), five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites. Besides the standard positioning service with positioning accuracy of about 10 m, both precise relative positioning and precise point positioning are already demonstrated. As is well known, precise orbit and clock determination is essential in enhancing precise positioning services. To improve the satellite orbits of the BeiDou regional system, we concentrate on the impact of the tracking geometry and the involvement of MEOs, and on the effect of integer ambiguity resolution as well. About seven weeks of data collected at the BeiDou Experimental Test Service (BETS) network is employed in this experimental study. Several tracking scenarios are defined, various processing schemata are designed and carried out; and then, the estimates are compared and analyzed in detail. The results show that GEO orbits, especially the along-track component, can be significantly improved by extending the tracking network in China along longitude direction, whereas IGSOs gain more improvement if the tracking network extends in latitude. The involvement of MEOs and ambiguity-fixing also make the orbits better.

Generation of Digital Surface Models from satellite photogrammetry: the DSM-OPT service of the ESA Geohazards Exploitation Platform (GEP)

Science.gov (United States)

Stumpf, André; Michéa, David; Malet, Jean-Philippe

2017-04-01

The continuously increasing fleet of agile stereo-capable very-high resolution (VHR) optical satellites has facilitated the acquisition of multi-view images of the earth surface. Theoretical revisit times have been reduced to less than one day and the highest spatial resolution which is commercially available amounts now to 30 cm/pixel. Digital Surface Models (DSM) and point clouds computed from such satellite stereo-acquisitions can provide valuable input for studies in geomorphology, tectonics, glaciology, hydrology and urban remote sensing The photogrammetric processing, however, still requires significant expertise, computational resources and costly commercial software. To enable a large Earth Science community (researcher and end-users) to process easily and rapidly VHR multi-view images, the work targets the implementation of a fully automatic satellite-photogrammetry pipeline (i.e DSM-OPT) on the ESA Geohazards Exploitation Platform (GEP). The implemented pipeline is based on the open-source photogrammetry library MicMac [1] and is designed for distributed processing on a cloud-based infrastructure. The service can be employed in pre-defined processing modes (i.e. urban, plain, hilly, and mountainous environments) or in an advanced processing mode (i.e. in which expert-users have the possibility to adapt the processing parameters to their specific applications). Four representative use cases are presented to illustrate the accuracy of the resulting surface models and ortho-images as well as the overall processing time. These use cases consisted of the construction of surface models from series of Pléiades images for four applications: urban analysis (Strasbourg, France), landslide detection in mountainous environments (South French Alps), co-seismic deformation in mountain environments (Central Italy earthquake sequence of 2016) and fault recognition for paleo-tectonic analysis (North-East India). Comparisons of the satellite-derived topography to airborne

An FDMA system concept for 30/20 GHz high capacity domestic satellite service

Science.gov (United States)

Berk, G.; Jean, P. N.; Rotholz, E.; White, B. E.

1982-01-01

The paper summarizes a feasibility study of a multibeam FDMA satellite system operating in the 30/20 GHz band. The system must accommodate a very high volume of traffic within the restrictions of a 5 kW solar cell array and a 2.5 GHz bandwidth. Multibeam satellite operation reduces the DC power demand and allows reuse of the available bandwidth. Interferences among the beams are brought to acceptable levels by appropriate frequency assignments. A transponder design is presented; it is greatly simplified by the application of a regional concept. System analysis shows that MSK modulation is appropriate for a high-capacity system because it conserves the frequency spectrum. Rain attenuation, a serious problem in this frequency band, is combatted with sufficient power margins and with coding. Link budgets, cost analysis, and weight and power calculations are also discussed. A satellite-routed FDMA system compares favorably in performance and cost with a satellite-switched TDMA system.

Modular approach for satellite communication ground terminals

Science.gov (United States)

Gould, G. R.

1984-01-01

The trend in satellite communications is toward completely digital, time division multiple access (TDMA) systems with uplink and downlink data rates dictated by the type of service offered. Trunking terminals will operate in the 550 MBPS (megabit per second) region uplink and downlink, whereas customer premise service (CPS) terminals will operate in the 25 to 10 MBPS region uplink and in the 200 MBPS region downlink. Additional criteria for the ground terminals will be to maintain clock sychronization with the system and burst time integrity to within a matter of nanoseconds, to process required order-fire information, to provide adaptive data scrambing, and to compensate for variations in the user input output data rates, and for changes in range in the satellite communications links resulting from satellite perturbations in orbit. To achieve the required adaptability of a ground terminal to the above mentioned variables, programmable building blocks can be developed that will meet all of these requirements. To maintain system synchronization, i.e., all bursted data arriving at the satellite within assigned TDMA windows, ground terminal transmit data rates and burst timing must be maintained within tight tolerances. With a programmable synchronizer as the heart of the terminal timing generation, variable data rates and burst timing tolerances are achievable. In essence, the unit inputs microprocessor generated timing words and outputs discrete timing pulses.

Remote sensing of wetlands at the Savannah River Plant

International Nuclear Information System (INIS)

Christensen, E.J.; Jensen, J.R.; Sharitz, R.R.

1985-01-01

The Savannah River Plant (SRP) occupies about 300 sq mi along a 10-mile stretch of the Savannah River. Large areas of wetlands cover the site, especially along tributary stream floodplains and the Savannah River. Some of these areas have been altered by cooling water discharges from nuclear production reactors onsite. To assess the effects of current and future plant operations on SRP and regional wetlands, an accurate quantitative survey was needed. Several studies were initiated to provide wetland acreage and distribution information: regional wetland inventories were provided from an analysis of LANDSAT multispectral scanner (MSS) satellite data. Wetlands were mapped throughout the entire Savannah River watershed and in the Savannah River floodplain. SRP wetlands were identified using a combination of LANDSAT MSS and Thematic Mapper satellite data and aerial photography. Wetlands in the SRP Savannah River swamp and thermally affected areas were mapped using high resolution MSS data collected from a low-flying aircraft. Vegetation communities in areas receiving cooling water discharges were then compared to surface temperatures measured from the airborne scanner at the same time to evaluate plant temperature tolerance. Historic changes to SRP wetlands from cooling water discharges were tabulated using aerial photography

Digital, Satellite-Based Aeronautical Communication

Science.gov (United States)

Davarian, F.

1989-01-01

Satellite system relays communication between aircraft and stations on ground. System offers better coverage with direct communication between air and ground, costs less and makes possible new communication services. Carries both voice and data. Because many data exchanged between aircraft and ground contain safety-related information, probability of bit errors essential.

Satellite communications: possibilities and problems

International Nuclear Information System (INIS)

Hine, M.

1986-01-01

Communication links via satellites are becoming available in Europe, both as part of the development of the telephone system and as special services aimed at data traffic. They offer the possibility of speeds between 50 kb/s and 2 Mb/s, without the problems and long term commitments of long distance land lines. Such links are provided by the PTT's as circuits which can be booked for variable periods, and have error rates which can be very low and well controlled. Problems in networking can arise from the satellite delay, particularly if errors occur in the local connections, and from the leased circuit and tariff philosophies of the PTT's. (Auth.)

A single-channel 10-bit 160 MS/s SAR ADC in 65 nm CMOS

International Nuclear Information System (INIS)

Lu Yuxiao; Sun Lu; Li Zhe; Zhou Jianjun

2014-01-01

This paper demonstrates a single-channel 10-bit 160 MS/s successive-approximation-register (SAR) analog-to-digital converter (ADC) in 65 nm CMOS process with a 1.2 V supply voltage. To achieve high speed, a new window-opening logic based on the asynchronous SAR algorithm is proposed to minimize the logic delay, and a partial set-and-down DAC with binary redundancy bits is presented to reduce the dynamic comparator offset and accelerate the DAC settling. Besides, a new bootstrapped switch with a pre-charge phase is adopted in the track and hold circuits to increase speed and reduce area. The presented ADC achieves 52.9 dB signal-to-noise distortion ratio and 65 dB spurious-free dynamic range measured with a 30 MHz input signal at 160 MHz clock. The power consumption is 9.5 mW and a core die area of 250 × 200 μm 2 is occupied. (semiconductor integrated circuits)

Performance Evaluation of Machine Learning Algorithms for Urban Pattern Recognition from Multi-spectral Satellite Images

Directory of Open Access Journals (Sweden)

Marc Wieland

2014-03-01

Full Text Available In this study, a classification and performance evaluation framework for the recognition of urban patterns in medium (Landsat ETM, TM and MSS and very high resolution (WorldView-2, Quickbird, Ikonos multi-spectral satellite images is presented. The study aims at exploring the potential of machine learning algorithms in the context of an object-based image analysis and to thoroughly test the algorithm’s performance under varying conditions to optimize their usage for urban pattern recognition tasks. Four classification algorithms, Normal Bayes, K Nearest Neighbors, Random Trees and Support Vector Machines, which represent different concepts in machine learning (probabilistic, nearest neighbor, tree-based, function-based, have been selected and implemented on a free and open-source basis. Particular focus is given to assess the generalization ability of machine learning algorithms and the transferability of trained learning machines between different image types and image scenes. Moreover, the influence of the number and choice of training data, the influence of the size and composition of the feature vector and the effect of image segmentation on the classification accuracy is evaluated.

Improvement of Ka-band satellite link availability for real-time IP-based video contribution

Directory of Open Access Journals (Sweden)

G. Berretta

2017-09-01

Full Text Available New High Throughput Satellite (HTS systems allow high throughput IP uplinks/contribution at Ka-band frequencies for relatively lower costs when compared to broadcasting satellite uplinks at Ku band. This technology offers an advantage for live video contribution from remote areas, where the terrestrial infrastructure may not be adequate. On the other hand, the Ka-band is more subject to impairments due to rain or bad weather. This paper addresses the target system specification and provides an optimized approach for the transmission of IP-based video flows through HTS commercial services operating at Ka-band frequencies. In particular, the focus of this study is on the service requirements and the propagation analysis that provide a reference architecture to improve the overall link availability. The approach proposed herein leads to the introduction of a new concept of live service contribution using pairs of small satellite antennas and cheap satellite terminals.

A Survey of Congestion Control Techniques and Data Link Protocols in Satellite Networks

OpenAIRE

Fahmy, Sonia; Jain, Raj; Lu, Fang; Kalyanaraman, Shivkumar

1998-01-01

Satellite communication systems are the means of realizing a global broadband integrated services digital network. Due to the statistical nature of the integrated services traffic, the resulting rate fluctuations and burstiness render congestion control a complicated, yet indispensable function. The long propagation delay of the earth-satellite link further imposes severe demands and constraints on the congestion control schemes, as well as the media access control techniques and retransmissi...

The next generation of Palapa satellite (Palapa-C)

Science.gov (United States)

Setiawan, Bambang

The Indonesian Palapa Communication Satellite System was established in Aug. 1976 when the first satellite of Palapa A series (Palapa A1) began operation. The system is owned and operated by PT. Telekomunikasi Indonesia (Telkom), which is a state owned company. The purpose of the system was to unify the telecommunications of the nation. Many years of operation have shown that satellite technology is the best solution for improving telecommunications in Indonesia. The system was started with 2 (two) satellites, each with 12 transponders (for a total of 24), and 40 earth stations. Now the system has 3 (three) satellites, each with 24 transponders (for a total of 72 transponders), and thousands of earth stations. The services have been extended to satisfy the requirements of the region as well as the original objectives. The use of satellite transponders in the region is increasing rapidly. In the next ten years, opportunities in the satellite communications business will become even more attractive. The next generation Palapa-C will incorporate improvements in capacity, quality, and coverage. The new frequency bands (ku- and Extended-C Band) will be used to meet the new transponder capacity requirements.

European Telecommunications Satellite II (EUTELSAT II)

Science.gov (United States)

Laemmel, G.; Brittinger, P.

1991-01-01

EUTELSAT II is a regional public telecommunications system for Europe. The services which will be provided are telephone and television. The satellites will be placed at a geostationary orbit within the arcs of 6 degrees east to 19 degrees east or 26 degrees to 36 degrees east. The designed lifetime is 7 years. After separation of the satellites from the launch vehicles, telemetry, telecommand, and ranging will be performed within the S-band frequencies. After positioning of the satellite at its final geostationary orbit, the Ku-band telecommunication equipment will be activated. From this time on, all satellite control operations will be performed in Ku-band. The Deep Space Network (DSN) will support the transfer and drift orbit mission phases. The coverage will consist of the 26-m antennas at Goldstone and Canberra as prime support for the transfer and drift orbits. Maximum support will consist of a 7-day period, plus 14 days of contingency support. Information is given in tabular form for DSN support, frequency assignments, telemetry, command, and tracking support responsibility.

Overview of NASA's In Space Robotic Servicing

Science.gov (United States)

Reed, Benjamin B.

2015-01-01

The panel discussion will start with a presentation of the work of the Satellite Servicing Capabilities Office (SSCO), a team responsible for the overall management, coordination, and implementation of satellite servicing technologies and capabilities for NASA. Born from the team that executed the five Hubble servicing missions, SSCO is now maturing a core set of technologies that support both servicing goals and NASA's exploration and science objectives, including: autonomous rendezvous and docking systems; dexterous robotics; high-speed, fault-tolerant computing; advanced robotic tools, and propellant transfer systems. SSCOs proposed Restore-L mission, under development since 2009, is rapidly advancing the core capabilities the fledgling satellite-servicing industry needs to jumpstart a new national industry. Restore-L is also providing key technologies and core expertise to the Asteroid Redirect Robotic Mission (ARRM), with SSCO serving as the capture module lead for the ARRM effort. Reed will present a brief overview of SSCOs history, capabilities and technologies.

An Assessment of State-of-the-Art Mean Sea Surface and Geoid Models of the Arctic Ocean: Implications for Sea Ice Freeboard Retrieval

DEFF Research Database (Denmark)

Skourup, Henriette; Farrell, Sinéad Louise; Hendricks, Stefan

2017-01-01

in a given model in the high frequency domain, primarily due to unresolved gravity features, can result in errors in the estimated along-track freeboard. These errors are exacerbated in areas with a sparse lead distribution in consolidated ice pack conditions. Additionally model errors can impact ocean......State-of-the-art Arctic Ocean mean sea surface (MSS) models and global geoid models (GGMs) are used to support sea ice freeboard estimation from satellite altimeters, as well as in oceanographic studies such as mapping sea level anomalies and mean dynamic ocean topography. However, errors...... geostrophic currents, derived from satellite altimeter data, while remaining biases in these models may impact longer-term, multi-sensor oceanographic time-series of sea level change in the Arctic. This study focuses on an assessment of five state-of-the-art Arctic MSS models (UCL13/04, DTU15...

Stigma, access to healthcare, and HIV risks among men who sell sex to men in Nigeria.

Science.gov (United States)

Crowell, Trevor A; Keshinro, Babajide; Baral, Stefan D; Schwartz, Sheree R; Stahlman, Shauna; Nowak, Rebecca G; Adebajo, Sylvia; Blattner, William A; Charurat, Manhattan E; Ake, Julie A

2017-04-20

Among men who have sex with men (MSM), men who sell sex (MSS) may be subject to increased sexual behaviour-related stigma that affects uptake of healthcare and risk of sexually transmitted infections (STIs). The objectives of this study were to characterize stigma, access to care, and prevalence of HIV among MSS in Nigeria. Respondent-driven sampling was used to recruit MSM in Abuja and Lagos into the ongoing TRUST/RV368 study, which provides HIV testing and treatment. Detailed behavioural data were collected by trained interviewers. MSS were identified by self-report of receiving goods or money in exchange for sex with men. Poisson regression with robust error variance was used to explore the impact of sex-selling on the risk of HIV. From 12 initial seed participants, 1552 men were recruited from March 2013-March 2016. Of these, 735 (47.4%) reported sex-selling. Compared to other MSM, MSS were younger (median 22 vs. 24 years, p harassment (39.2% vs. 26.8%, p sexual behaviour-related stigma affecting MSS, as compared with other MSM, that limits uptake of healthcare services. The distinct characteristics and risks among MSS suggest the need for specific interventions to optimize linkage to HIV prevention and treatment services in Nigeria.

National Space Science Data Center and World Data Center A for Rockets and Satellites - Ionospheric data holdings and services

Science.gov (United States)

Bilitza, D.; King, J. H.

1988-01-01

The activities and services of the National Space Science data Center (NSSDC) and the World Data Center A for Rockets and Satellites (WDC-A-R and S) are described with special emphasis on ionospheric physics. The present catalog/archive system is explained and future developments are indicated. In addition to the basic data acquisition, archiving, and dissemination functions, ongoing activities include the Central Online Data Directory (CODD), the Coordinated Data Analysis Workshopps (CDAW), the Space Physics Analysis Network (SPAN), advanced data management systems (CD/DIS, NCDS, PLDS), and publication of the NSSDC News, the SPACEWARN Bulletin, and several NSSD reports.

Optical burst switching based satellite backbone network

Science.gov (United States)

Li, Tingting; Guo, Hongxiang; Wang, Cen; Wu, Jian

2018-02-01

We propose a novel time slot based optical burst switching (OBS) architecture for GEO/LEO based satellite backbone network. This architecture can provide high speed data transmission rate and high switching capacity . Furthermore, we design the control plane of this optical satellite backbone network. The software defined network (SDN) and network slice (NS) technologies are introduced. Under the properly designed control mechanism, this backbone network is flexible to support various services with diverse transmission requirements. Additionally, the LEO access and handoff management in this network is also discussed.

Use of Openly Available Satellite Images for Remote Sensing Education

Science.gov (United States)

Wang, C.-K.

2011-09-01

With the advent of Google Earth, Google Maps, and Microsoft Bing Maps, high resolution satellite imagery are becoming more easily accessible than ever. It have been the case that the college students may already have wealth experiences with the high resolution satellite imagery by using these software and web services prior to any formal remote sensing education. It is obvious that the remote sensing education should be adjusted to the fact that the audience are already the customers of remote sensing products (through the use of the above mentioned services). This paper reports the use of openly available satellite imagery in an introductory-level remote sensing course in the Department of Geomatics of National Cheng Kung University as a term project. From the experience learned from the fall of 2009 and 2010, it shows that this term project has effectively aroused the students' enthusiastic toward Remote Sensing.

Intra- and inter-population polymorphism in Coletinia maggii (Grassi, 1887) (Zygentoma: Nicoletiidae), an inhabitant of soil, mesovoid shallow substratum (MSS) and caves--A challenge for the strict classification of subterranean fauna?

Science.gov (United States)

Gilgado, José D; Ortuño, Vicente M

2015-02-19

New locations of Coletinia maggii (Grassi, 1887) have been discovered in the center of the Iberian Peninsula in different types of subterranean environments, such as a stony layer in the subsoil of an alluvial plain, an alluvial Mesovoid Shallow Substratum or Milieu Souterrain Superficiel (MSS) and a gypsum cave. This is the first record of both an alluvial MSS in the center of the Iberian Peninsula and of a subterranean species living in it. The high number of specimens captured allowed the first detailed study of the morphological intra- and inter-population variations of this species. The implications of its presence in these different environments, its wide distribution area across Europe, and the relevance of the morphological variation in the characters for the taxonomy of this species are discussed. Based on the results, Coletinia hernandoi Molero, Bach & Gaju, 2013 is proposed as a new synonym of C. maggii.

Network design consideration of a satellite-based mobile communications system

Science.gov (United States)

Yan, T.-Y.

1986-01-01

Technical considerations for the Mobile Satellite Experiment (MSAT-X), the ground segment testbed for the low-cost spectral efficient satellite-based mobile communications technologies being developed for the 1990's, are discussed. The Network Management Center contains a flexible resource sharing algorithm, the Demand Assigned Multiple Access scheme, which partitions the satellite transponder bandwidth among voice, data, and request channels. Satellite use of multiple UHF beams permits frequency reuse. The backhaul communications and the Telemetry, Tracking and Control traffic are provided through a single full-coverage SHF beam. Mobile Terminals communicate with the satellite using UHF. All communications including SHF-SHF between Base Stations and/or Gateways, are routed through the satellite. Because MSAT-X is an experimental network, higher level network protocols (which are service-specific) will be developed only to test the operation of the lowest three levels, the physical, data link, and network layers.

A geostationary satellite system for mobile multimedia applications using portable, aeronautical and mobile terminals

Science.gov (United States)

Losquadro, G.; Luglio, M.; Vatalaro, F.

1997-01-01

A geostationary satellite system for mobile multimedia services via portable, aeronautical and mobile terminals was developed within the framework of the Advanced Communications Technology Service (ACTS) programs. The architecture of the system developed under the 'satellite extremely high frequency communications for multimedia mobile services (SECOMS)/ACTS broadband aeronautical terminal experiment' (ABATE) project is presented. The system will be composed of a Ka band system component, and an extremely high frequency band component. The major characteristics of the space segment, the ground control station and the portable, aeronautical and mobile user terminals are outlined.

Korea Earth Observation Satellite Program

Science.gov (United States)

Baek, Myung-Jin; Kim, Zeen-Chul

via Korea Aerospace Research Institute (KARI) as the prime contractor in the area of Korea earth observation satellite program to enhance Korea's space program development capability. In this paper, Korea's on-going and future earth observation satellite programs are introduced: KOMPSAT- 1 (Korea Multi Purpose Satellite-1), KOMPSAT-2 and Communication, Broadcasting and Meteorological Satellite (CBMS) program. KOMPSAT-1 satellite successfully launched in December 1999 with Taurus launch vehicle. Since launch, KOMPSAT-1 is downlinking images of Korea Peninsular every day. Until now, KOMPSAT-1 has been operated more than 2 and half years without any major hardware malfunction for the mission operation. KOMPSAT-1 payload has 6.6m panchromatic spatial resolution at 685 km on-orbit and the spacecraft bus had NASA TOMS-EP (Total Ozone Mapping Spectrometer-Earth Probe) spacecraft bus heritage designed and built by TRW, U.S.A.KOMPSAT-1 program was international co-development program between KARI and TRW funded by Korean Government. be launched in 2004. Main mission objective is to provide geo-information products based on the multi-spectral high resolution sensor called Multi-Spectral Camera (MSC) which will provide 1m panchromatic and 4m multi-spectral high resolution images. ELOP of Israel is the prime contractor of the MSC payload system and KARI is the total system prime contractor including spacecraft bus development and ground segment. KARI also has the contract with Astrium of Europe for the purpose of technical consultation and hardware procurement. Based on the experience throughout KOMPSAT-1 and KOMPSAT-2 space system development, Korea is expecting to establish the infrastructure of developing satellite system. Currently, KOMPSAT-2 program is in the critical design stage. are scheduled to launch in 2008 and in 2014, respectively. The mission of CBMS consists of two areas. One is of space technology test for the communications mission, and the other is of a real

Cyber security with radio frequency interferences mitigation study for satellite systems

Science.gov (United States)

Wang, Gang; Wei, Sixiao; Chen, Genshe; Tian, Xin; Shen, Dan; Pham, Khanh; Nguyen, Tien M.; Blasch, Erik

2016-05-01

Satellite systems including the Global Navigation Satellite System (GNSS) and the satellite communications (SATCOM) system provide great convenience and utility to human life including emergency response, wide area efficient communications, and effective transportation. Elements of satellite systems incorporate technologies such as navigation with the global positioning system (GPS), satellite digital video broadcasting, and information transmission with a very small aperture terminal (VSAT), etc. The satellite systems importance is growing in prominence with end users' requirement for globally high data rate transmissions; the cost reduction of launching satellites; development of smaller sized satellites including cubesat, nanosat, picosat, and femtosat; and integrating internet services with satellite networks. However, with the promising benefits, challenges remain to fully develop secure and robust satellite systems with pervasive computing and communications. In this paper, we investigate both cyber security and radio frequency (RF) interferences mitigation for satellite systems, and demonstrate that they are not isolated. The action space for both cyber security and RF interferences are firstly summarized for satellite systems, based on which the mitigation schemes for both cyber security and RF interferences are given. A multi-layered satellite systems structure is provided with cross-layer design considering multi-path routing and channel coding, to provide great security and diversity gains for secure and robust satellite systems.

Fewer intensive care unit refusals and a higher capacity utilization by using a cyclic surgical case schedule

NARCIS (Netherlands)

van Houdenhoven, Mark; van Oostrum, Jeroen M.; Wullink, Gerhard; Hans, Elias W.; Hurink, Johann L.; Bakker, Jan; Kazemier, Geert

Purpose: Mounting health care costs force hospital managers to maximize utilization of scarce resources and simultaneously improve access to hospital services. This article assesses the benefits of a cyclic case scheduling approach that exploits a master surgical schedule (MSS). An MSS maximizes

Auction based spectrum management of cognitive radio networks

DEFF Research Database (Denmark)

Chang, H. B.; Chen, K.-C.; Prasad, Ramjee

2009-01-01

(PS-MSs), and we therefore construct a cognitive radio network (CRN) consisting of a PRN with multiple CR-MSs. We propose a spectrum management policy framework such that CR-MSs can compete in utilization of the PRN spectrum bands available to opportunistic transmission of CR-MSs by Vickrey auction...... to the PRN, the overall spectrum utilization, the profit of the service provider, the spectrum access opportunity of the CR-MSs are increased to achieve cowin situation for every party in cognitive radio networks.......Cognitive radio (CR) technology is considered as an effective solution to enhance overall spectrum efficiency, especially primary radio network (PRN) typically having relatively low spectrum utilization. However, to realize CR concept, it is essential to provide enough incentives to PRN and extra...

Worldwide satellite communications for the energy utility industry. Final report

International Nuclear Information System (INIS)

Skelton, R.L.

1998-07-01

Recent and future generations of low earth orbiting (LEO) satellites are promising new possibilities for using space communications to achieve operational improvements and business expansion in energy supply and delivery industries. The ability to reach remote locations with relatively inexpensive devices and infrastructure is a unique property of satellites. Applications include remote monitoring and control of distributed resources and emergency and personal communication. Satellite systems are emerging as a significant opportunity for investment minded utilities. Over a dozen groups are planning to launch a total of 1200 LEOs in the period from 1996 to 2006, at a probable cost of over $20 Billion. This large number of systems can provide a worldwide mix of narrow band and wideband services including data, voice, video and Internet access. This paper examines the two primary factors which have limited applications in the energy industry: cost and propagation delay. The former has so far limited the technology to fixed communications with a few important sites such as remote substations. The latter has rendered the technology unsuitable for applications where critical protection mechanisms are involved. These constraints are effectively countered by the emerging LEO systems. Big LEOs will be used for voice service, little LEOs will be the systems of choice for most utility data applications. The author concludes that there are good technical and business reasons to reconsider future satellite communications as an option for meeting certain strategic business objectives in power system management and customer oriented information services

Satellite end of life constraints: Technical and organisational solutions

Science.gov (United States)

Cabrières, Bernard; Alby, Fernand; Cazaux, Christian

2012-04-01

Since 1974 with the radiocommunication satellite Symphony1, CNES launched and operated 11 GEO and 20 LEO satellites. During those 36 years, both flight segment and ground segment dramatically evolved and operational organisations and techniques equally improved. At the present time, CNES operates 1 GEO satellite and 17 LEO satellites with not much more people and costs than in 1986 when its first Satellite Operation Direction in Toulouse was only in charge of Telecom1A, Telecom1B and Spot1. This fantastic technical evolution combined with the huge increase of services to citizens and governments given by Space systems was unfortunately also associated with an enormous growth of space pollution by debris of all sizes. From the beginning, CNES was a major actor of the international effort to promote regulations in order to try to reduce or at least control this problematic situation. Internally, CNES, not only set up an operational on-call service to deal with collision risks, but decided to do its best to apply the new guidelines to the end of life of satellites under its responsibility even for those developed and launched a very long time ago. For instance, that was the case in 2009 for the reorbitation of the GEO satellite Telecom 2C (launched in 1995) and for the deorbitation of the LEO satellite Spot2 (launched in 1990). In addition, CNES prepares procedures to be able to be as exemplary as possible for its other spacecrafts whose end of life approaches. The constraints and challenges to face in order to cope with these new requirements are multiple: choice of final orbit, realistic calculation of re-entry duration, estimation of residual propellant, electric passivation, management of explosion risks… All these studies and operational experience gained will be helpful for the new role of CNES, which recently became in charge of controlling space operators in the frame of the new French space law on space operations.

The Future of Satellite Communications. Resource Management and the Needs of Nations.

Science.gov (United States)

Hinchman, Walter R.; Dunn, D. A.

Recent events suggest that Intelsat (the 68-nation International Telecommunications Satellite Consortium) will coordinate a number of domestic and regional systems that provide satellite communications services, some of which will be maintained by Intelsat and some of which will be independent. This report addresses the problems of conflict in…

Broadband and scalable mobile satellite communication system for future access networks

Science.gov (United States)

Ohata, Kohei; Kobayashi, Kiyoshi; Nakahira, Katsuya; Ueba, Masazumi

2005-07-01

Due to the recent market trends, NTT has begun research into next generation satellite communication systems, such as broadband and scalable mobile communication systems. One service application objective is to provide broadband Internet access for transportation systems, temporal broadband access networks and telemetries to remote areas. While these are niche markets the total amount of capacity should be significant. We set a 1-Gb/s total transmission capacity as our goal. Our key concern is the system cost, which means that the system should be unified system with diversified services and not tailored for each application. As satellites account for a large portion of the total system cost, we set the target satellite size as a small, one-ton class dry mass with a 2-kW class payload power. In addition to the payload power and weight, the mobile satellite's frequency band is extremely limited. Therefore, we need to develop innovative technologies that will reduce the weight and maximize spectrum and power efficiency. Another challenge is the need for the system to handle up to 50 dB and a wide data rate range of other applications. This paper describes the key communication system technologies; the frequency reuse strategy, multiplexing scheme, resource allocation scheme, and QoS management algorithm to ensure excellent spectrum efficiency and support a variety of services and quality requirements in the mobile environment.

Interactive access to LP DAAC satellite data archives through a combination of open-source and custom middleware web services

Science.gov (United States)

Davis, Brian N.; Werpy, Jason; Friesz, Aaron M.; Impecoven, Kevin; Quenzer, Robert; Maiersperger, Tom; Meyer, David J.

2015-01-01

Current methods of searching for and retrieving data from satellite land remote sensing archives do not allow for interactive information extraction. Instead, Earth science data users are required to download files over low-bandwidth networks to local workstations and process data before science questions can be addressed. New methods of extracting information from data archives need to become more interactive to meet user demands for deriving increasingly complex information from rapidly expanding archives. Moving the tools required for processing data to computer systems of data providers, and away from systems of the data consumer, can improve turnaround times for data processing workflows. The implementation of middleware services was used to provide interactive access to archive data. The goal of this middleware services development is to enable Earth science data users to access remote sensing archives for immediate answers to science questions instead of links to large volumes of data to download and process. Exposing data and metadata to web-based services enables machine-driven queries and data interaction. Also, product quality information can be integrated to enable additional filtering and sub-setting. Only the reduced content required to complete an analysis is then transferred to the user.

Development and validation of satellite-based estimates of surface visibility

Science.gov (United States)

Brunner, J.; Pierce, R. B.; Lenzen, A.

2016-02-01

A satellite-based surface visibility retrieval has been developed using Moderate Resolution Imaging Spectroradiometer (MODIS) measurements as a proxy for Advanced Baseline Imager (ABI) data from the next generation of Geostationary Operational Environmental Satellites (GOES-R). The retrieval uses a multiple linear regression approach to relate satellite aerosol optical depth, fog/low cloud probability and thickness retrievals, and meteorological variables from numerical weather prediction forecasts to National Weather Service Automated Surface Observing System (ASOS) surface visibility measurements. Validation using independent ASOS measurements shows that the GOES-R ABI surface visibility retrieval (V) has an overall success rate of 64.5 % for classifying clear (V ≥ 30 km), moderate (10 km ≤ V United States Environmental Protection Agency (EPA) and National Park Service (NPS) Interagency Monitoring of Protected Visual Environments (IMPROVE) network and provide useful information to the regional planning offices responsible for developing mitigation strategies required under the EPA's Regional Haze Rule, particularly during regional haze events associated with smoke from wildfires.

Development and validation of satellite based estimates of surface visibility

Science.gov (United States)

Brunner, J.; Pierce, R. B.; Lenzen, A.

2015-10-01

A satellite based surface visibility retrieval has been developed using Moderate Resolution Imaging Spectroradiometer (MODIS) measurements as a proxy for Advanced Baseline Imager (ABI) data from the next generation of Geostationary Operational Environmental Satellites (GOES-R). The retrieval uses a multiple linear regression approach to relate satellite aerosol optical depth, fog/low cloud probability and thickness retrievals, and meteorological variables from numerical weather prediction forecasts to National Weather Service Automated Surface Observing System (ASOS) surface visibility measurements. Validation using independent ASOS measurements shows that the GOES-R ABI surface visibility retrieval (V) has an overall success rate of 64.5% for classifying Clear (V ≥ 30 km), Moderate (10 km ≤ V United States Environmental Protection Agency (EPA) and National Park Service (NPS) Interagency Monitoring of Protected Visual Environments (IMPROVE) network, and provide useful information to the regional planning offices responsible for developing mitigation strategies required under the EPA's Regional Haze Rule, particularly during regional haze events associated with smoke from wildfires.

How Satellites Have Contributed to Building a Weather Ready Nation

Science.gov (United States)

Lapenta, W.

2017-12-01

NOAA's primary mission since its inception has been to reduce the loss of life and property, as well as disruptions from, high impact weather and water-related events. In recent years, significant societal losses resulting even from well forecast extreme events have shifted attention from the forecast alone toward ensuring societal response is equal to the risks that exist for communities, businesses and the public. The responses relate to decisions ranging from coastal communities planning years in advance to mitigate impacts from rising sea level, to immediate lifesaving decisions such as a family seeking adequate shelter during a tornado warning. NOAA is committed to building a "Weather-Ready Nation" where communities are prepared for and respond appropriately to these events. The Weather-Ready Nation (WRN) strategic priority is building community resilience in the face of increasing vulnerability to extreme weather, water, climate and environmental threats. To build a Weather-Ready Nation, NOAA is enhancing Impact-Based Decision Support Services (IDSS), transitioning science and technology advances into forecast operations, applying social science research to improve the communication and usefulness of information, and expanding its dissemination efforts to achieve far-reaching readiness, responsiveness and resilience. These four components of Weather-Ready Nation are helping ensure NOAA data, products and services are fully utilized to minimize societal impacts from extreme events. Satellite data and satellite products have been important elements of the national Weather Service (NWS) operations for more than 40 years. When one examines the uses of satellite data specific to the internal forecast and warning operations of NWS, two main applications are evident. The first is the use of satellite data in numerical weather prediction models; the second is the use of satellite imagery and derived products for mesoscale and short-range weather warning and

Satellite Image Classification of Building Damages Using Airborne and Satellite Image Samples in a Deep Learning Approach

Science.gov (United States)

Duarte, D.; Nex, F.; Kerle, N.; Vosselman, G.

2018-05-01

The localization and detailed assessment of damaged buildings after a disastrous event is of utmost importance to guide response operations, recovery tasks or for insurance purposes. Several remote sensing platforms and sensors are currently used for the manual detection of building damages. However, there is an overall interest in the use of automated methods to perform this task, regardless of the used platform. Owing to its synoptic coverage and predictable availability, satellite imagery is currently used as input for the identification of building damages by the International Charter, as well as the Copernicus Emergency Management Service for the production of damage grading and reference maps. Recently proposed methods to perform image classification of building damages rely on convolutional neural networks (CNN). These are usually trained with only satellite image samples in a binary classification problem, however the number of samples derived from these images is often limited, affecting the quality of the classification results. The use of up/down-sampling image samples during the training of a CNN, has demonstrated to improve several image recognition tasks in remote sensing. However, it is currently unclear if this multi resolution information can also be captured from images with different spatial resolutions like satellite and airborne imagery (from both manned and unmanned platforms). In this paper, a CNN framework using residual connections and dilated convolutions is used considering both manned and unmanned aerial image samples to perform the satellite image classification of building damages. Three network configurations, trained with multi-resolution image samples are compared against two benchmark networks where only satellite image samples are used. Combining feature maps generated from airborne and satellite image samples, and refining these using only the satellite image samples, improved nearly 4 % the overall satellite image

Satellite systems for personal applications concepts and technology

CERN Document Server

Richharia, Madhavendra

2010-01-01

Presents the concepts, technology, and role of satellite systems in support of personal applications, such as mobile and broadband communications, navigation, television, radio and multimedia broadcasting, safety of life services, etc. This book presents a novel perspective on satellite systems, reflecting the modern personal technology context, and hence a focus on the individual as end-user. The book begins by outlining key generic concepts before discussing techniques adopted in particular application areas; next, it exemplifies these techniques through discussion of state-of-art c

47 CFR 25.261 - Procedures for avoidance of in-line interference events for Non Geostationary Satellite Orbit...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Procedures for avoidance of in-line interference events for Non Geostationary Satellite Orbit (NGSO) Satellite Network Operations in the Fixed Satellite Service (FSS) Bands. 25.261 Section 25.261 Telecommunication FEDERAL COMMUNICATIONS COMMISSION...

A service for the application of data quality information to NASA earth science satellite records

Science.gov (United States)

Armstrong, E. M.; Xing, Z.; Fry, C.; Khalsa, S. J. S.; Huang, T.; Chen, G.; Chin, T. M.; Alarcon, C.

2016-12-01

A recurring demand in working with satellite-based earth science data records is the need to apply data quality information. Such quality information is often contained within the data files as an array of "flags", but can also be represented by more complex quality descriptions such as combinations of bit flags, or even other ancillary variables that can be applied as thresholds to the geophysical variable of interest. For example, with Level 2 granules from the Group for High Resolution Sea Surface Temperature (GHRSST) project up to 6 independent variables could be used to screen the sea surface temperature measurements on a pixel-by-pixel basis. Quality screening of Level 3 data from the Soil Moisture Active Passive (SMAP) instrument can be become even more complex, involving 161 unique bit states or conditions a user can screen for. The application of quality information is often a laborious process for the user until they understand the implications of all the flags and bit conditions, and requires iterative approaches using custom software. The Virtual Quality Screening Service, a NASA ACCESS project, is addressing these issues and concerns. The project has developed an infrastructure to expose, apply, and extract quality screening information building off known and proven NASA components for data extraction and subset-by-value, data discovery, and exposure to the user of granule-based quality information. Further sharing of results through well-defined URLs and web service specifications has also been implemented. The presentation will focus on overall description of the technologies and informatics principals employed by the project. Examples of implementations of the end-to-end web service for quality screening with GHRSST and SMAP granules will be demonstrated.

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.

Integrating Communication and Navigation: Next Generation Broadcast Service (NGBS)

Science.gov (United States)

Donaldson, Jennifer

2017-01-01

NASA Goddard has been investing in technology demonstrations of a beacon service, now called Next Generation Broadcast Services (NGBS). NGBS is a global, space-based, communications and navigation service for users of Global Navigation Satellite Systems (GNSS) and the Tracking and Data Relay Satellite System (TDRSS). NGBS will provide an S-band beacon messaging source and radio navigation available to users at orbital altitudes 1400 km and below, increasing the autonomy and resiliency of onboard communication and navigation. NGBS will deliver both one-way radiometric (Doppler and pseudorange) and fast forward data transport services to users. Portions of the overall forward data volume will be allocated for fixed message types while the remaining data volume will be left for user forward command data. The NGBS signal will reside within the 2106.43 MHz spectrum currently allocated for the Space Networks multiple access forward (MAF) service and a live service demonstration is currently being planned via the 2nd and 3rd generation TDRS satellites.

Commercial TV distribution and broadcast by satellite in the USA

Science.gov (United States)

Debastos, R.

The evolution of DBS satellite systems and their market in the U.S. is described. Anik A, launched in 1972, has been followed by 40 other launches. By 1986 there were 30 functional DBS systems in orbit operating in either C- or K- or hybrid modes of the two bands and providing over 450 channels to subscribers. The television capabilities are being augmented, with FCC approval for 31 new satellites, with Ku-band video, telephony and data transmission systems for small businesses. Features of the RCA Series 4000 and 5000 third generation satellites which will provide the services and lower operating costs passed on to the consumer are summarized, noting the use of TWTAs and high efficiency thermal dissipation systems on the new satellite designs.

Comparison of LANDSAT-2 and field spectrometer reflectance signatures of south Texas rangeland plant communities

Science.gov (United States)

Richardson, A. J.; Escobar, D. E.; Gausman, H. W.; Everitt, J. H. (Principal Investigator)

1982-01-01

The accuracy was assessed for an atmospheric correction method that depends on clear water bodies to infer solar and atmospheric parameters for radiative transfer equations by measuring the reflectance signature of four prominent south Texas rangeland plants with the LANDSAT satellite multispectral scanner (MSS) and a ground based spectroradiometer. The rangeland plant reflectances produced by the two sensors were correlated with no significant deviation of the slope from unity or of the intercept from zero. These results indicated that the atmospheric correction produced LANDSAT MSS estimates of rangeland plant reflectances that are as accurate as the ground based spectroradiometer.

Power attenuation characteristics as switch-over criterion in personal satellite mobile communications

Science.gov (United States)

Castro, Jonathan P.

1993-01-01

A third generation mobile system intends to support communications in all environments (i.e., outdoors, indoors at home or office and when moving). This system will integrate services that are now available in architectures such as cellular, cordless, mobile data networks, paging, including satellite services to rural areas. One way through which service integration will be made possible is by supporting a hierarchical cellular structure based on umbrella cells, macro cells, micro and pico cells. In this type of structure, satellites are part of the giant umbrella cells allowing continuous global coverage, the other cells belong to cities, neighborhoods, and buildings respectively. This does not necessarily imply that network operation of terrestrial and satellite segments interconnect to enable roaming and spectrum sharing. However, the cell concept does imply hand-off between different cell types, which may involve change of frequency. Within this propsective, the present work uses power attenuation characteristics to determine a dynamic criterion that allows smooth transition from space to terrestrial networks. The analysis includes a hybrid channel that combines Rician, Raleigh and Log Normal fading characteristics.

Protocoles d'accès multiple orientés qualité de service en constellation de satellite à orbite basse

OpenAIRE

Ibrahim , Abbas

2002-01-01

Pendant les dernières années, le réseau cellulaire est devenu accessible presque partout. Pour compléter ce réseau cellulaire terrestre, plusieurs systèmes basés sur des satellites à basse orbite (LEO Low Earth Orbit) et moyenne orbite (MEO Medium Earth Orbit) ont été développés pour offrir une couverture globale. Les services multimédias sont largement demandés sur une échelle globale.Notre but est de développer une couche d'accès MAC au canal satellitaire tout en respectant les contraintes ...

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.

Kajian metode Subjective Global Assessment (SGA dan Nutrition Services Screening Assesment (NSSA sebagai status gizi awal pasien dewasa sebagai prediktor lama rawat inap dan status pulang

Directory of Open Access Journals (Sweden)

Agustinus I Wayan Harimawan

2011-03-01

Full Text Available Background: Assessment of nutrition status of newly hospitalized patients is an initial stage of nutrition intervention which will bring effects to the duration of stay and the history of patients' diseases during hospitalization. Appropriate nutrition intervention as part of  patients' care can be used as an indicator of the quality of hospital service. Objective: The study aimed to identify preliminary nutrition status of newly hospitalized adult patients using SGA method, its effects to length of stay and status of discharge and compare the capacity of SGA and NSSA indicators in predicting length of stay and status of discharge of adult patients. Method: This observational study used prospective cohort study design. It was carried out at Anuntaloko Hospital of Parigi, District of Parigi Moutong, Sulawesi Tengah from July to September 2008. Subject consisted of 162 people comprising 82 undernourished people and 80 people with good nutrition status based on assessment using SGA method. Data analysis used bivariable and multivariable, receiver operating characteristics (ROC curve and diagnostic methods using computer program. Result: The majority of newly hospitalized patients were undernourished (50.6%; preliminary status of patients assessed using SGA method could affect length of stay, relative risk (RR=3.67 but not status of discharge (RR=0.97. The capacity of SGA indicator, area under the curve (AUC=0.81 and maximum sum of sensitivity and specifcity (MSS =1.57 was better than NSSA indicator (AUC=0.76 and MSS 1.43 in predicting length of stay. The capacity of SGA indicator (AUC=0.50 and MSS=1.01 was better than NSSA indicator (AUC=0.49 and MSS=0.98 in predicting discharge status of the patient. Conclusion: SGA and NSSA indicators could be implemented in assessing preliminary nutrition status of newly hospitalized adult patients; SGA indicator had better capacity than NSSA indicator.

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

Positional stabilization of communications satellites - The RITA ion propulsion system is ready for commercial use

Science.gov (United States)

The radiofrequency ion thruster assembly (RITA) intended for service aboard the new Artemis communications satellite will operate for three hours twice a day, in order to furnish orbital position adjustments that keep antennas accurately pointed toward the earth. These engines are, despite such frequent and sustained use, projected to eject no more than 30 kG of Xe over the course of a decade. RITA operation is also extremely reliable and, due to its very low propellant consumption, is the basis of a long satellite service life. RITA will be among the 15 experiments that are to be performed by ESA's Eureca research satellite.

Mapping Water Use and Drought with Satellite Remote Sensing

OpenAIRE

Anderson, Martha

2014-01-01

Mapping water use and drought with satellite remote sensing. Martha C. Anderson, Bill Kustas, Feng Gao, Kate Semmens. USDA-Agricultural Research Service Hydrology and Remote Sensing Laboratory, Beltsville, MD. Chris Hain NOAA-NESDIS

GSFC network operations with Tracking and Data Relay Satellites

Science.gov (United States)

Spearing, R.; Perreten, D. E.

The Tracking and Data Relay Satellite System (TDRSS) Network (TN) has been developed to provide services to all NASA User spacecraft in near-earth orbits. Three inter-relating entities will provide these services. The TN has been transformed from a network continuously changing to meet User specific requirements to a network which is flexible to meet future needs without significant changes in operational concepts. Attention is given to the evolution of the TN network, the TN capabilities-space segment, forward link services, tracking services, return link services, the three basic capabilities, single access services, multiple access services, simulation services, the White Sands Ground Terminal, the NASA communications network, and the network control center.

a European Global Navigation Satellite System — the German Market and Value Adding Chain Effects

Science.gov (United States)

Vollerthun, A.; Wieser, M.

2002-03-01

Since Europe is considering to establish a "market-driven" European Global Navigation Satellite System, the German Center of Aerospace initiated a market research to justify a German investment in such a European project. The market research performed included the following market segments: aviation, railway, road traffic, shipping, surveying, farming, military, space applications, leisure, and sport. In these market segments, the forementioned inputs were determined for satellite navigation hardware (receivers) as well as satellite navigation services. The forecast period was from year 2007 to 2017. For the considered period, the market amounts to a total of DM 83.0 billion (approx. US $50 billion), whereas the satellite navigation equipment market makes up DM 39.8 billion, and charges for value-added-services amount to DM 43.2 billion. On closer examination road traffic can be identified as the dominant market share, both in the receiver-market and service-market. With a share of 96% for receivers and 73% for services the significance of the road traffic segment becomes obvious. The second part of this paper investigates the effects the market potential has on the Value-Adding-Chain. Therefore, all participants in the Value-Adding-Chain are identified, using industrial cost structure models the employment effect is analyzed, and possible tax revenues for the state are examined.

Detecting agricultural to urban land use change from multi-temporal MSS digital data. [Salt Lake County, Utah

Science.gov (United States)

Ridd, M. K.; Merola, J. A.; Jaynes, R. A.

1983-01-01

Conversion of agricultural land to a variety of urban uses is a major problem along the Wasatch Front, Utah. Although LANDSAT MSS data is a relatively coarse tool for discriminating categories of change in urban-size plots, its availability prompts a thorough test of its power to detect change. The procedures being applied to a test area in Salt Lake County, Utah, where the land conversion problem is acute are presented. The identity of land uses before and after conversion was determined and digital procedures for doing so were compared. Several algorithms were compared, utilizing both raw data and preprocessed data. Verification of results involved high quality color infrared photography and field observation. Two data sets were digitally registered, specific change categories internally identified in the software, results tabulated by computer, and change maps printed at 1:24,000 scale.

A Method for Estimating BeiDou Inter-frequency Satellite Clock Bias

Directory of Open Access Journals (Sweden)

LI Haojun

2016-02-01

Full Text Available A new method for estimating the BeiDou inter-frequency satellite clock bias is proposed, considering the shortage of the current methods. The constant and variable parts of the inter-frequency satellite clock bias are considered in the new method. The data from 10 observation stations are processed to validate the new method. The characterizations of the BeiDou inter-frequency satellite clock bias are also analyzed using the computed results. The results of the BeiDou inter-frequency satellite clock bias indicate that it is stable in the short term. The estimated BeiDou inter-frequency satellite clock bias results are molded. The model results show that the 10 parameters of model for each satellite can express the BeiDou inter-frequency satellite clock bias well and the accuracy reaches cm level. When the model parameters of the first day are used to compute the BeiDou inter-frequency satellite clock bias of the second day, the accuracy also reaches cm level. Based on the stability and modeling, a strategy for the BeiDou satellite clock service is presented to provide the reference of our BeiDou.

Flight Dynamics Operations Management of the Large and Heterogeneous Eutelsat Fleet of Commercial Satellites

Science.gov (United States)

Bellido, E.

The EUTELSAT FDU (Flight Dynamics Unit) manages the resources to perform the typical activities of the large satellite operators and faces the usual difficulties raising from a vast and heterogeneous fleet. At present 20 satellites from 9 different platforms/sub-platforms are controlled from our Satellite Control Centre. The FDU was created in 2002 with the aim to respond to the operational needs of a growing fleet in terms of number of satellites and activities. It is at present composed of 6 engineering staff with the objective to provide operations service covering the whole lifecycle of the satellites from the procurement phase till the decommissioning. The most demanding activity is the daily operations, which must ensure maximum safety and continuity of service with the highest efficiency. Solutions have been applied from different areas: management, structure, operations organisation, processes, facilities, quality standards, etc. In addition to this, EUTELSAT is a growing communications operator and the FDU needs to contribute to the global objectives of the company. This paper covers our approach.

42 CFR 410.78 - Telehealth services.

Science.gov (United States)

2010-10-01

...-based renal dialysis center (including satellites). (vii) A skilled nursing facility (as defined in... as telehealth services. (f) Process for adding or deleting services. Changes to the list of Medicare...

Planning and Scheduling for Fleets of Earth Observing Satellites

Science.gov (United States)

Frank, Jeremy; Jonsson, Ari; Morris, Robert; Smith, David E.; Norvig, Peter (Technical Monitor)

2001-01-01

We address the problem of scheduling observations for a collection of earth observing satellites. This scheduling task is a difficult optimization problem, potentially involving many satellites, hundreds of requests, constraints on when and how to service each request, and resources such as instruments, recording devices, transmitters, and ground stations. High-fidelity models are required to ensure the validity of schedules; at the same time, the size and complexity of the problem makes it unlikely that systematic optimization search methods will be able to solve them in a reasonable time. This paper presents a constraint-based approach to solving the Earth Observing Satellites (EOS) scheduling problem, and proposes a stochastic heuristic search method for solving it.

Preparing Precipitation Data Access, Value-added Services and Scientific Exploration Tools for the Integrated Multi-satellitE Retrievals for GPM (IMERG)

Science.gov (United States)

Ostrenga, D.; Liu, Z.; Kempler, S. J.; Vollmer, B.; Teng, W. L.

2013-12-01

The Precipitation Data and Information Services Center (PDISC) (http://disc.gsfc.nasa.gov/precipitation or google: NASA PDISC), located at the NASA Goddard Space Flight Center (GSFC) Earth Sciences (GES) Data and Information Services Center (DISC), is home of the Tropical Rainfall Measuring Mission (TRMM) data archive. For over 15 years, the GES DISC has served not only TRMM, but also other space-based, airborne-based, field campaign and ground-based precipitation data products to the precipitation community and other disciplinary communities as well. The TRMM Multi-Satellite Precipitation Analysis (TMPA) products are the most popular products in the TRMM product family in terms of data download and access through Mirador, the GES-DISC Interactive Online Visualization ANd aNalysis Infrastructure (Giovanni) and other services. The next generation of TMPA, the Integrated Multi-satellitE Retrievals for GPM (IMERG) to be released in 2014 after the launch of GPM, will be significantly improved in terms of spatial and temporal resolutions. To better serve the user community, we are preparing data services and samples are listed below. To enable scientific exploration of Earth science data products without going through complicated and often time consuming processes, such as data downloading, data processing, etc., the GES DISC has developed Giovanni in consultation with members of the user community, requesting quick search, subset, analysis and display capabilities for their specific data of interest. For example, the TRMM Online Visualization and Analysis System (TOVAS, http://disc2.nascom.nasa.gov/Giovanni/tovas/) has proven extremely popular, especially as additional datasets have been added upon request. Giovanni will continue to evolve to accommodate GPM data and the multi-sensor data inter-comparisons that will be sure to follow. Additional PDISC tool and service capabilities being adapted for GPM data include: An on-line PDISC Portal (includes user guide, etc

Evaluation of spacecraft technology programs (effects on communication satellite business ventures), volume 1

Science.gov (United States)

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

1985-01-01

Commercial organizations as well as government agencies invest in spacecraft (S/C) technology programs that are aimed at increasing the performance of communications satellites. The value of these programs must be measured in terms of their impacts on the financial performane of the business ventures that may ultimately utilize the communications satellites. An economic evaluation and planning capability was developed and used to assess the impact of NASA on-orbit propulsion and space power programs on typical fixed satellite service (FSS) and direct broadcast service (DBS) communications satellite business ventures. Typical FSS and DBS spin and three-axis stabilized spacecraft were configured in the absence of NASA technology programs. These spacecraft were reconfigured taking into account the anticipated results of NASA specified on-orbit propulsion and space power programs. In general, the NASA technology programs resulted in spacecraft with increased capability. The developed methodology for assessing the value of spacecraft technology programs in terms of their impact on the financial performance of communication satellite business ventures is described. Results of the assessment of NASA specified on-orbit propulsion and space power technology programs are presented for typical FSS and DBS business ventures.

Satellite data transferring subsystem based on system 'Materik'

International Nuclear Information System (INIS)

Belogub, V.P.; Kal'schikov, I.B.; Kirillov, Yu.K.; Kulikov, V.N.; Shumov, A.N.

1998-01-01

One of the most important indicators of successful function of the International Monitoring System is existence of highly reliable communication channels providing transfer data from observation points in a real time scales. Up to present, the most communication channels were provided with existing VF-channels (Voice Frequency) that are relatively low-speedy in transfer process (4.8-9.6 kbit/sec.). In addition, reliability of the channels is insufficient because of many retransmission points. In connection with it, the special control service of MD RF decided to improve the information transfer system (ITS) installed between the observation point and National Data Center (Dubna-city). The improvement of the ITS comprises replacement of wire lines of VF-channels with satellite ones within the framework of the computer-aided satellite communication system (CASCS) M aterik . Besides it was considered to be expedient that the satellite system of data transfer from NPP to the Crisis Center of 'ROSENERGOATOM' Concern would be combined with CASCS M aterik , using the facilities of the Central Earth Station of Satellite Communication (CESSC) in Dubna. Such approach to the creation of Satellite communication has advantages in solution of radiation safety and global monitoring issues

Evaluation of SLAR and thematic mapper MSS data for forest cover mapping using computer-aided analysis techniques. [south carolina

Science.gov (United States)

Hoffer, R. M. (Principal Investigator)

1979-01-01

A literature review on radar and spectral band information was conducted and a NC-130 mission was flown carrying the NS001 scanner system which basically corresponds to the channel configuration of the proposed thematic mapper. Aerial photography and other reference data were obtained for the study site, an area approximately 290 sq miles in north central South Carolina. A cover type map was prepared and methods were devised for reformatting and geometrically correcting MSS CRT data. Arrangements were made to obtain LANDSAT data for dates approximating the NC-130 mission. Because of the waveband employed to obtain SEASAT radar data, it was decided to determine if X-band (2.40 cm to 3.75 cm wavelength) imagery is available.

47 CFR 25.278 - Additional coordination obligation for non-geostationary and geostationary satellite systems in...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Additional coordination obligation for non-geostationary and geostationary satellite systems in frequencies allocated to the fixed-satellite service. 25.278 Section 25.278 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER...

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.

Simulating Global AeroMACS Airport Ground Station Antenna Power Transmission Limits to Avoid Interference With Mobile Satellite Service Feeder Uplinks

Science.gov (United States)

Wilson, Jeffrey D.

2013-01-01

The Aeronautical Mobile Airport Communications System (AeroMACS), which is based upon the IEEE 802.16e mobile wireless standard, is expected to be implemented in the 5091 to 5150 MHz frequency band. As this band is also occupied by Mobile Satellite Service feeder uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference are under analysis in order to enable the definition of standards that assure that such interference will be avoided. In this study, the cumulative interference power distribution at low Earth orbit from transmitters at global airports was simulated with the Visualyse Professional software. The dependence of the interference power on antenna distribution, gain patterns, duty cycle, and antenna tilt was simulated. As a function of these parameters, the simulation results are presented in terms of the limitations on transmitter power from global airports required to maintain the cumulative interference power under the established threshold.

Tracking and Data Relay Satellite System /TDRSS/ telecommunication services

Science.gov (United States)

Deerkoski, L. F.

1975-01-01

The TDRSS and tracking services define the telecommunication performance of the TDRSS between the RF interface with user spacecraft and the data interface with NASCOM at the ground terminal. Attention is given to system constraints, forward link services, multiple-access signal design parameters, S-band single access signal design parameters, multiple-access return link services, and single-access return link services.

Static and kinematic positioning using WADGPS from geostationary satellites

Science.gov (United States)

Cefalo, R.; Gatti, M.

2003-04-01

STATIC AND KINEMATIC POSITIONING USING WADGPS CORRECTIONS FROM GEOSTATIONARY SATELLITES Cefalo R. (1), Gatti M (2) (1) Department of Civil Engineering, University of Trieste, P.le Europa 1, 34127 Trieste, Italy, cefalo@dic.univ.trieste.it, (2) Department of Engineering, University of Ferrara, via Saragat 1, 44100 Ferrara, Italy, mgatti@ing.unife.it ABSTRACT. Starting from February 2000, static and kinematic experiments have been performed at the Department of Civil Engineering of University of Trieste, Italy and the Department of Engineering of University of Ferrara, Italy, using the WADGPS (Wide Area Differential GPS) corrections up linked by Geostationary Satellites belonging to the American WAAS and European EGNOS. Recently, a prototypal service by ESA (European Space Agency) named SISNet (Signal In Space through Internet), has been introduced using Internet to diffuse the messages up linked through AOR-E and IOR Geostationary Satellites. This service will overcome the problems relative to the availability of the corrections in urban areas. This system is currently under tests by the authors in order to verify the latency of the message and the applicability and accuracies obtainable in particular in dynamic applications.

DOD Use of Commercial Wideband Satellite Communications Systems: How Much is Needed, and How Do We Get It?

National Research Council Canada - National Science Library

Hutchens, Robert

2001-01-01

..., A key enabler to this end is sufficient wideband satellite communications connectivity DoD's organic wideband satellite communications capabilities are inadequate, so commercial services must be used...

gProcess and ESIP Platforms for Satellite Imagery Processing over the Grid

Science.gov (United States)

Bacu, Victor; Gorgan, Dorian; Rodila, Denisa; Pop, Florin; Neagu, Gabriel; Petcu, Dana

2010-05-01

The Environment oriented Satellite Data Processing Platform (ESIP) is developed through the SEE-GRID-SCI (SEE-GRID eInfrastructure for regional eScience) co-funded by the European Commission through FP7 [1]. The gProcess Platform [2] is a set of tools and services supporting the development and the execution over the Grid of the workflow based processing, and particularly the satelite imagery processing. The ESIP [3], [4] is build on top of the gProcess platform by adding a set of satellite image processing software modules and meteorological algorithms. The satellite images can reveal and supply important information on earth surface parameters, climate data, pollution level, weather conditions that can be used in different research areas. Generally, the processing algorithms of the satellite images can be decomposed in a set of modules that forms a graph representation of the processing workflow. Two types of workflows can be defined in the gProcess platform: abstract workflow (PDG - Process Description Graph), in which the user defines conceptually the algorithm, and instantiated workflow (iPDG - instantiated PDG), which is the mapping of the PDG pattern on particular satellite image and meteorological data [5]. The gProcess platform allows the definition of complex workflows by combining data resources, operators, services and sub-graphs. The gProcess platform is developed for the gLite middleware that is available in EGEE and SEE-GRID infrastructures [6]. gProcess exposes the specific functionality through web services [7]. The Editor Web Service retrieves information on available resources that are used to develop complex workflows (available operators, sub-graphs, services, supported resources, etc.). The Manager Web Service deals with resources management (uploading new resources such as workflows, operators, services, data, etc.) and in addition retrieves information on workflows. The Executor Web Service manages the execution of the instantiated workflows

Comparative study of FDMA, TDMA and hybrid 30/20 GHz satellite communications systems for small users

Science.gov (United States)

Berk, G.; Jean, P. N.; Rotholz, E.

1982-01-01

This study compares several satellite uplink and downlink accessing schemes for a Customer Premises Service. Four conceptual system designs are presented: Satellite-Routed FDMA, Frequency-Routed TDMA, Satellite-Switched TDMA, and Processor-Routed TDMA, operating in the 30/20 GHz band. The designs are compared on the basis of estimated satellite weight, power consumption, and cost. The system capacities are analyzed for a fixed multibeam coverage of CONUS. Analysis shows that the system capacity is limited by the available satellite resources and by the terminal size and cost.

Detecting and quantifying land use/land cover dynamics in Wadla ...

African Journals Online (AJOL)

A study was conducted in Wadla Delanta Massif to investigate land use/cover dynamics over the last four decades (1973-2014) using satellite images (1973 MSS, 1995 TM and 2014 ETM+). Global positioning system ... in the study area. Keywords: GIS, Image classification, Remote sensing, Supervised classification ...

Operational monitoring and forecasting of bathing water quality through exploiting satellite Earth observation and models: The AlgaRisk demonstration service

Science.gov (United States)

Shutler, J. D.; Warren, M. A.; Miller, P. I.; Barciela, R.; Mahdon, R.; Land, P. E.; Edwards, K.; Wither, A.; Jonas, P.; Murdoch, N.; Roast, S. D.; Clements, O.; Kurekin, A.

2015-04-01

Coastal zones and shelf-seas are important for tourism, commercial fishing and aquaculture. As a result the importance of good water quality within these regions to support life is recognised worldwide and a number of international directives for monitoring them now exist. This paper describes the AlgaRisk water quality monitoring demonstration service that was developed and operated for the UK Environment Agency in response to the microbiological monitoring needs within the revised European Union Bathing Waters Directive. The AlgaRisk approach used satellite Earth observation to provide a near-real time monitoring of microbiological water quality and a series of nested operational models (atmospheric and hydrodynamic-ecosystem) provided a forecast capability. For the period of the demonstration service (2008-2013) all monitoring and forecast datasets were processed in near-real time on a daily basis and disseminated through a dedicated web portal, with extracted data automatically emailed to agency staff. Near-real time data processing was achieved using a series of supercomputers and an Open Grid approach. The novel web portal and java-based viewer enabled users to visualise and interrogate current and historical data. The system description, the algorithms employed and example results focussing on a case study of an incidence of the harmful algal bloom Karenia mikimotoi are presented. Recommendations and the potential exploitation of web services for future water quality monitoring services are discussed.

14 CFR 1215.103 - Services.

Science.gov (United States)

2010-01-01

... Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION TRACKING AND DATA RELAY SATELLITE SYSTEM... transmission service. (4) Emergency line outage recording in the event of a communications failure between...-launch support planning and documentation. (9) Scheduling user services via TDRSS. (10) Access to...

Operational use of open satellite data for marine water quality monitoring

Science.gov (United States)

Symeonidis, Panagiotis; Vakkas, Theodoros

2017-09-01

The purpose of this study was to develop an operational platform for marine water quality monitoring using near real time satellite data. The developed platform utilizes free and open satellite data available from different data sources like COPERNICUS, the European Earth Observation Initiative, or NASA, from different satellites and instruments. The quality of the marine environment is operationally evaluated using parameters like chlorophyll-a concentration, water color and Sea Surface Temperature (SST). For each parameter, there are more than one dataset available, from different data sources or satellites, to allow users to select the most appropriate dataset for their area or time of interest. The above datasets are automatically downloaded from the data provider's services and ingested to the central, spatial engine. The spatial data platform uses the Postgresql database with the PostGIS extension for spatial data storage and Geoserver for the provision of the spatial data services. The system provides daily, 10 days and monthly maps and time series of the above parameters. The information is provided using a web client which is based on the GET SDI PORTAL, an easy to use and feature rich geospatial visualization and analysis platform. The users can examine the temporal variation of the parameters using a simple time animation tool. In addition, with just one click on the map, the system provides an interactive time series chart for any of the parameters of the available datasets. The platform can be offered as Software as a Service (SaaS) to any area in the Mediterranean region.

Application of Vision Metrology to In-Orbit Measurement of Large Reflector Onboard Communication Satellite for Next Generation Mobile Satellite Communication

Science.gov (United States)

Akioka, M.; Orikasa, T.; Satoh, M.; Miura, A.; Tsuji, H.; Toyoshima, M.; Fujino, Y.

2016-06-01

Satellite for next generation mobile satellite communication service with small personal terminal requires onboard antenna with very large aperture reflector larger than twenty meters diameter because small personal terminal with lower power consumption in ground base requires the large onboard reflector with high antenna gain. But, large deployable antenna will deform in orbit because the antenna is not a solid dish but the flexible structure with fine cable and mesh supported by truss. Deformation of reflector shape deteriorate the antenna performance and quality and stability of communication service. However, in case of digital beam forming antenna with phased array can modify the antenna beam performance due to adjustment of excitation amplitude and excitation phase. If we can measure the reflector shape precisely in orbit, beam pattern and antenna performance can be compensated with the updated excitation amplitude and excitation phase parameters optimized for the reflector shape measured every moment. Softbank Corporation and National Institute of Information and Communications Technology has started the project "R&D on dynamic beam control technique for next generation mobile communication satellite" as a contracted research project sponsored by Ministry of Internal Affairs and Communication of Japan. In this topic, one of the problem in vision metrology application is a strong constraints on geometry for camera arrangement on satellite bus with very limited space. On satellite in orbit, we cannot take many images from many different directions as ordinary vision metrology measurement and the available area for camera positioning is quite limited. Feasibility of vision metrology application and general methodology to apply to future mobile satellite communication satellite is to be found. Our approach is as follows: 1) Development of prototyping simulator to evaluate the expected precision for network design in zero order and first order 2) Trial

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

Trends in the commercial launch services industry

Science.gov (United States)

Haase, Ethan E.

2001-02-01

The market for space launch services has undergone significant development in the last two decades and is poised to change even further. With the introduction of new players in the market, and the development of new vehicles by existing providers, competition has increased. At the same time, customer payloads have been changing as satellites grow in size and capability. Amidst these changes, launch delays have become a concern in the industry, and launch service providers have developed different solutions to avoid delays and satisfy customer needs. This analysis discusses these trends in the launch services market and their drivers. Focus is given to the market for medium, intermediate, and heavy launch services which generally includes launches of GEO communication satellites, large government payloads, and NGSO constellations. .

Propagation considerations in land mobile satellite transmission

Science.gov (United States)

Vogel, W. J.; Smith, E. K.

1985-01-01

It appears likely that the Land Mobile Satellite Services (LMSS) will be authorized by the FCC for operation in the 800 to 900 MHz (UHF) and possibly near 1500 MHz (L-band). Propagation problems are clearly an important factor in the effectiveness of this service, but useful measurements are few, and produced contradictory interpretations. A first order overview of existing measurements is presented with particular attention to the first two NASA balloon to mobile vehicle propagation experiments. Some physical insight into the interpretation of propagation effects in LMSS transmissions is provided.

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.

Global mobile satellite communications theory for maritime, land and aeronautical applications

CERN Document Server

Ilčev, Stojče Dimov

2017-01-01

This book discusses current theory regarding global mobile satellite communications (GMSC) for maritime, land (road and rail), and aeronautical applications. It covers how these can enable connections between moving objects such as ships, road and rail vehicles and aircrafts on one hand, and on the other ground telecommunications subscribers through the medium of communications satellites, ground earth stations, Terrestrial Telecommunication Networks (TTN), Internet Service Providers (ISP) and other wireless and landline telecommunications providers. This new edition covers new developments and initiatives that have resulted in land and aeronautical applications and the introduction of new satellite constellations in non-geostationary orbits and projects of new hybrid satellite constellations. The book presents current GMSC trends, mobile system concepts and network architecture using a simple mode of style with understandable technical information, characteristics, graphics, illustrations and mathematics equ...

The UNOSAT-GRID Project: Access to Satellite Imagery through the Grid Environment

CERN Document Server

Méndez-Lorenzo, P; Lamanna, M; Meyer, X; Lazeyras, M; Bjorgo, E; Retiere, A; Falzone, A; Venuti, N; Maccarone, S; Ugolotti, B

2007-01-01

UNOSAT is a United Nations activity to provide access to satellite images and geographic system services for humanitarian operations for rescue or aid activities. UNOSAT is implemented by the UN Institute for Training and Research (UNITAR) and managed by the UN Office for Project Services (UNOPS). In addition, partners from different organizations constitute the UNOSAT consortium. Among these partners, CERN participates actively providing the required computational and storage resources. The critical part of the UNOSAT activity is the storage and processing of large quantities of satellite images. The fast and secure access to these images from any part of the world is mandatory during these activities. Based on two successful CERN-GRID/UNOSAT pilot projects (data storage/compression/download and image access through mobile phone), the GRIDUNOSAT project has consolidated the considerable work undertaken so far in the present activity. The main use case already demonstrated is the delivery of satellite images ...

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

On board processing for future satellite communications systems: Comparison of FDM, TDM and hybrid accessing schemes

Science.gov (United States)

Berk, G.; Jean, P. N.; Rotholz, E.

1982-01-01

Several satellite uplink and downlink accessing schemes for customer premises service are compared. Four conceptual system designs are presented: satellite-routed frequency division multiple access (FDMA), satellite-switched time division multiple access (TDMA), processor-routed TDMA, and frequency-routed TDMA, operating in the 30/20 GHz band. The designs are compared on the basis of estimated satellite weight, system capacity, power consumption, and cost. The systems are analyzed for fixed multibeam coverage of the continental United States. Analysis shows that the system capacity is limited by the available satellite resources and by the terminal size and cost.

INMARSAT - The International Maritime Satellite Organization: Origins and structure

Science.gov (United States)

Doyle, S. E.

1977-01-01

The third session of the International Conference on the Establishment of an International Maritime Satellite System established the International Maritime Satellite Organization (INMARSAT) in 1976. Its main functions are to improve maritime communications via satellite, thereby facilitating more efficient emergency communications, ship management, and maritime public correspondence services. INMARSAT's aims are similar to those of the Intergovernmental Maritime Consultative Organization (IMCO), the main United Nations organization dealing with maritime affairs. The specific functions of INMARSAT have been established by an Intersessional Working Group (IWG) which met three times between general conference meetings. Initial investment shares for the creation of INMARSAT were shared by the United States (17%), the United Kingdom (12%), the U.S.S.R. (11%), Norway (9.50%), Japan (8.45%), Italy (4.37%), and France (3.50%).

Local network interconnection through a satellite point-to-multipoint link. Ph.D. Thesis - Ecole Nationale Superieure des Telecommunications, 6 Jul. 1985

Science.gov (United States)

Duarte, O. Muniz Bandeira

1986-01-01

Four architectures to implement a point to multipoint satellite link protocol for communication services offered by the Telecom 1 satellite network are presented. A safe communication service with error correction and flow control facilities is described. It is shown that a time transparent communication system combines simplicity and cost advantages.

Triple Play over Satellite, Ka-Band Making the Difference

Science.gov (United States)

Benoit, Guillaume; Fenech, Hector; Pezzana, Stefano

Over the last years a number of operators have been deploying satellite-based consumer internet access services to reduce the digital divide and capture the market of households not covered by ADSL, cable or wireless broadband. These operators are proposing a step change improvement in the economics of consumer service, with lower terminal costs, broadband access with monthly fees comparable to ADSL and an integrated technology simplifying the process of terminal installation, provisioning and management.

LMSS - From low data rate to voice services

Science.gov (United States)

Rogard, R.

1992-03-01

An overview of ESA's approach towards the introduction of Land Mobile Communications in Europe is presented. Emphasis is placed on a description of the payload called EMS to be launched on a host satellite, the Italsat-F2 spacecraft, and the definition of services which are most appropriate for a first-generation-operating Land Mobile Satellite System, namely, PRODAT, a message-handling system, and Europhone, an original approach to 'voice' systems. Attention is given to the EMS payload, characteristics, and capacity, the IF processor and channelization, and market considerations. It is shown that the optimization of the satellite characteristics and the mix of services to be provided are the key elements of a successful entry into the market.

Improved land use classification from Landsat and Seasat satellite imagery registered to a common map base

Science.gov (United States)

Clark, J.

1981-01-01

In the case of Landsat Multispectral Scanner System (MSS) data, ambiguities in spectral signature can arise in urban areas. A study was initiated in the belief that Seasat digital SAR could help provide the spectral separability needed for a more accurate urban land use classification. A description is presented of the results of land use classifications performed on Landsat and preprocessed Seasat imagery that were registered to a common map base. The process of registering imagery and training site boundary coordinates to a common map has been reported by Clark (1980). It is found that preprocessed Seasat imagery provides signatures for urban land uses which are spectrally separable from Landsat signatures. This development appears to significantly improve land use classifications in an urban setting for class 12 (Commercial and Services), class 13 (Industrial), and class 14 (Transportation, Communications, and Utilities).

A network architecture for International Business Satellite communications

Science.gov (United States)

Takahata, Fumio; Nohara, Mitsuo; Takeuchi, Yoshio

Demand Assignment (DA) control is expected to be introduced in the International Business Satellte communications (IBS) network in order to cope with a growing international business traffic. The paper discusses the DA/IBS network from the viewpoints of network configuration, satellite channel configuration and DA control. The network configuration proposed here consists of one Central Station with network management function and several Network Coordination Stations with user management function. A satellite channel configuration is also presented along with a tradeoff study on transmission bit rate, high power amplifier output power requirement, and service quality. The DA control flow and protocol based on CCITT Signalling System No. 7 are also proposed.

Secure, Autonomous, Intelligent Controller for Integrating Distributed Emergency Response Satellite Operations

Science.gov (United States)

Ivancic, William D.; Paulsen, Phillip E.; Miller, Eric M.; Sage, Steen P.

2013-01-01

This report describes a Secure, Autonomous, and Intelligent Controller for Integrating Distributed Emergency Response Satellite Operations. It includes a description of current improvements to existing Virtual Mission Operations Center technology being used by US Department of Defense and originally developed under NASA funding. The report also highlights a technology demonstration performed in partnership with the United States Geological Service for Earth Resources Observation and Science using DigitalGlobe(Registered TradeMark) satellites to obtain space-based sensor data.

Advance Technology Satellites in the Commercial Environment. Volume 2: Final Report

Science.gov (United States)

1984-01-01

A forecast of transponder requirements was obtained. Certain assumptions about system configurations are implicit in this process. The factors included are interpolation of baseline year values to produce yearly figures, estimation of satellite capture, effects of peak-hours and the time-zone staggering of peak hours, circuit requirements for acceptable grade of service capacity of satellite transponders, including various compression methods where applicable, and requirements for spare transponders in orbit. The graphical distribution of traffic requirements was estimated.

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.

Current state of art of satellite altimetry

Science.gov (United States)

Łyszkowicz, Adam Bolesław; Bernatowicz, Anna

2017-12-01

One of the fundamental problems of modern geodesy is precise defi nition of the gravitational fi eld and its changes in time. This is essential in positioning and navigation, geophysics, geodynamics, oceanography and other sciences related to the climate and Earth's environment. One of the major sources of gravity data is satellite altimetry that provides gravity data with almost 75% surface of the Earth. Satellite altimetry also provides data to study local, regional and global geophysical processes, the geoid model in the areas of oceans and seas. This technique can be successfully used to study the ocean mean dynamic topography. The results of the investigations and possible products of altimetry will provide a good material for the GGOS (Global Geodetic Observing System) and institutions of IAS (International Altimetry Service). This paper presents the achievements in satellite altimetry in all the above disciplines obtained in the last years. First very shorly basic concept of satellite altimetry is given. In order to obtain the highest accuracy on range measurements over the ocean improved of altimetry waveforms performed on the ground is described. Next, signifi cant improvements of sea and ocean gravity anomalies models developed presently is shown. Study of sea level and its extremes examined, around European and Australian coasts using tide gauges data and satellite altimetry measurements were described. Then investigations of the phenomenon of the ocean tides, calibration of altimeters, studies of rivers and ice-sheets in the last years are given.

Current state of art of satellite altimetry

Directory of Open Access Journals (Sweden)

Łyszkowicz Adam Bolesław

2017-12-01

Full Text Available One of the fundamental problems of modern geodesy is precise defi nition of the gravitational fi eld and its changes in time. This is essential in positioning and navigation, geophysics, geodynamics, oceanography and other sciences related to the climate and Earth’s environment. One of the major sources of gravity data is satellite altimetry that provides gravity data with almost 75% surface of the Earth. Satellite altimetry also provides data to study local, regional and global geophysical processes, the geoid model in the areas of oceans and seas. This technique can be successfully used to study the ocean mean dynamic topography. The results of the investigations and possible products of altimetry will provide a good material for the GGOS (Global Geodetic Observing System and institutions of IAS (International Altimetry Service. This paper presents the achievements in satellite altimetry in all the above disciplines obtained in the last years. First very shorly basic concept of satellite altimetry is given. In order to obtain the highest accuracy on range measurements over the ocean improved of altimetry waveforms performed on the ground is described. Next, signifi cant improvements of sea and ocean gravity anomalies models developed presently is shown. Study of sea level and its extremes examined, around European and Australian coasts using tide gauges data and satellite altimetry measurements were described. Then investigations of the phenomenon of the ocean tides, calibration of altimeters, studies of rivers and ice-sheets in the last years are given.

Enhanced Mean Dynamic Topography And Ocean Circulation Estimation Using Goce Preliminary Mode

DEFF Research Database (Denmark)

Knudsen, Per; Bingham, Rory; Andersen, Ole Baltazar

2011-01-01

have been combined with the recent DNSC08MSS mean sea surface model to construct a global GOCE satellite-only mean dynamic topography model. At a first glance, the GOCE MDT display the well known features related to the major ocean current systems. A closer look, however, reveals that the improved...

Cibola flight experiment satellite

Science.gov (United States)

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

2004-11-01

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

Forecast of space shuttle flight requirements for launch of commercial communications satellites

Science.gov (United States)

1977-01-01

The number of communication satellites required over the next 25 years to support domestic and regional communication systems for telephony, telegraphy and other low speed data; video teleconferencing, new data services, direct TV broadcasting; INTELSAT; and maritime and aeronautical services was estimated to determine the number of space shuttle flights necessary for orbital launching.

In-Space Internet-Based Communications for Space Science Platforms Using Commercial Satellite Networks

Science.gov (United States)

Kerczewski, Robert J.; Bhasin, Kul B.; Fabian, Theodore P.; Griner, James H.; Kachmar, Brian A.; Richard, Alan M.

1999-01-01

The continuing technological advances in satellite communications and global networking have resulted in commercial systems that now can potentially provide capabilities for communications with space-based science platforms. This reduces the need for expensive government owned communications infrastructures to support space science missions while simultaneously making available better service to the end users. An interactive, high data rate Internet type connection through commercial space communications networks would enable authorized researchers anywhere to control space-based experiments in near real time and obtain experimental results immediately. A space based communications network architecture consisting of satellite constellations connecting orbiting space science platforms to ground users can be developed to provide this service. The unresolved technical issues presented by this scenario are the subject of research at NASA's Glenn Research Center in Cleveland, Ohio. Assessment of network architectures, identification of required new or improved technologies, and investigation of data communications protocols are being performed through testbed and satellite experiments and laboratory simulations.

Graphical Programming: A systems approach for telerobotic servicing of space assets

International Nuclear Information System (INIS)

Pinkerton, J.T.; Patten, R.

1993-01-01

Satellite servicing is in many ways analogous to subsea robotic servicing in the late 1970's. A cost effective, reliable, telerobotic capability had to be demonstrated before the oil companies invested money in deep water robot serviceable production facilities. In the same sense, aeronautic engineers will not design satellites for telerobotic servicing until such a quantifiable capability has been demonstrated. New space servicing systems will be markedly different than existing space robot systems. Past space manipulator systems, including the Space Shuttle's robot arm, have used master/slave technologies with poor fidelity, slow operating speeds and most importantly, in-orbit human operators. In contrast, new systems will be capable of precision operations, conducted at higher rates of speed, and be commanded via ground-control communication links. Challenges presented by this environment include achieving a mandated level of robustness and dependability, radiation hardening, minimum weight and power consumption, and a system which accommodates the inherent communication delay between the ground station and the satellite. There is also a need for a user interface which is easy to use, ensures collision free motions, and is capable of adjusting to an unknown workcell (for repair operations the condition of the satellite may not be known in advance). This paper describes the novel technologies required to deliver such a capability

PEGASUS - A Flexible Launch Solution for Small Satellites with Unique Requirements

Science.gov (United States)

Richards, B. R.; Ferguson, M.; Fenn, P. D.

The financial advantages inherent in building small satellites are negligible if an equally low cost launch service is not available to deliver them to the orbit they require. The weight range of small satellites puts them within the capability of virtually all launch vehicles. Initially, this would appear to help drive down costs through competition since, by one estimate, there are roughly 75 active space launch vehicles around the world that either have an established flight record or are planning to make an inaugural launch within the year. When reliability, budget constraints, and other issues such as inclination access are factored in, this list of available launch vehicles is often times reduced to a very limited few, if any at all. This is especially true for small satellites with unusual or low inclination launch requirements where the cost of launching on the heavy-lift launchers that have the capacity to execute the necessary plane changes or meet the mission requirements can be prohibitive. For any small satellite, reducing launch costs by flying as a secondary or even tertiary payload is only advantageous in the event that a primary payload can be found that either requires or is passing through the same final orbit and has a launch date that is compatible. If the satellite is able to find a ride on a larger vehicle that is only passing through the correct orbit, the budget and technical capability must exist to incorporate a propulsive system on the satellite to modify the orbit to that required for the mission. For these customers a launch vehicle such as Pegasus provides a viable alternative due to its proven flight record, relatively low cost, self- contained launch infrastructure, and mobility. Pegasus supplements the existing world-wide launch capability by providing additional services to a targeted niche of payloads that benefit greatly from Pegasus' mobility and flexibility. Pegasus can provide standard services to satellites that do not

Characterizing SPDY over High Latency Satellite Channels

Directory of Open Access Journals (Sweden)

Luca Caviglione

2014-12-01

Full Text Available The increasing complexity ofWeb contents and the growing diffusion of mobile terminals, which use wireless and satellite links to get access to the Internet, impose the adoption of more specialized protocols. In particular, we focus on SPDY, a novel protocol introduced by Google to optimize the retrieval of complex webpages, to manage large Round Trip Times and high packet losses channels. In this perspective, the paper characterizes SPDY over high latency satellite links, especially with the goal of understanding whether it could be an efficient solution to cope with performance degradations typically affecting Web 2.0 services. To this aim, we implemented an experimental set-up, composed of an ad-hoc proxy, a wireless link emulator, and an instrumented Web browser. The results clearly indicate that SPDY can enhance the performances in terms of loading times, and reduce the traffic fragmentation. Moreover, owing to its connection multiplexing architecture, SPDY can also mitigate the transport layer complexity, which is critical when in presence of Performance Enhancing Proxies usually deployed to isolate satellite trunks.

47 CFR 25.284 - Emergency Call Center Service.

Science.gov (United States)

2010-10-01

... mobile satellite service to end-user customers (part 25, subparts A-D) must provide Emergency Call Center... Center personnel must determine the emergency caller's phone number and location and then transfer or otherwise redirect the call to an appropriate public safety answering point. Providers of mobile satellite...

78 FR 8229 - Service Rules for Advanced Wireless Services in the 2000-2020 MHz and 2180-2200 MHz Bands, etc.

Science.gov (United States)

2013-02-05

... band in this proceeding; such determinations are outside its scope. However, in our role as spectrum... the AWS-4 and 2 GHz MSS uplink bands and harmful overload interference, if any occurs, from operators...

Customer premises services market demand assessment 1980 - 2000. Volume 1: Executive summary

Science.gov (United States)

Gamble, R. B.; Saporta, L.; Heidenrich, G. A.

1983-01-01

Estimates of market demand for domestic civilian telecommunications services for the years 1980 to 2000 are provided. Overall demand, demand or satellite services, demand for satellite delivered Customer Premises Service (CPS), and demand for 30/20 GHz Customer Premises Services are covered. Emphasis is placed on the CPS market and demand is segmented by market, by service, by user class and by geographic region. Prices for competing services are discussed and the distribution of traffic with respect to distance is estimated. A nationwide traffic distribution model for CPS in terms of demand for CPS traffic and earth stations for each of the major SMSAs in the United States are provided.

Nigeria's Satellite Programme Development: Prospects and Challenges

Science.gov (United States)

Akinyede, Joseph

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

Estimating the chlorophyll content in the waters of Guanabara Bay from the LANDSAT multispectral scanning digital data

Science.gov (United States)

Dejesusparada, N. (Principal Investigator); Bentancurt, J. J. V.; Herz, B. R.; Molion, L. B.

1980-01-01

Detection of water quality in Guanabara Bay using multispectral scanning digital data taken from LANDSAT satellites was examined. To test these processes, an empirical (statistical) approach was choosen to observe the degree of relationship between LANDSAT data and the in situ data taken simultaneously. The linear and nonlinear regression analyses were taken from among those developed by INPE in 1978. Results indicate that the major regression was in the number six MSS band, atmospheric effects, which indicated a correction coefficient of 0.99 and an average error of 6.59 micrograms liter. This error was similar to that obtained in the laboratory. The chlorophyll content was between 0 and 100 micrograms/liter, as taken from the MSS of LANDSAT.

Development, Validation, and Potential Enhancements to the Second-Generation Operational Aerosol Product at the National Environmental Satellite, Data, and Information Service of the National Oceanic and Atmospheric Administration

Science.gov (United States)

Stowe, Larry L.; Ignatov, Alexander M.; Singh, Ramdas R.

1997-01-01

A revised (phase 2) single-channel algorithm for aerosol optical thickness, tau(sup A)(sub SAT), retrieval over oceans from radiances in channel 1 (0.63 microns) of the Advanced Very High Resolution Radiometer (AVHRR) has been implemented at the National Oceanic and Atmospheric Administration's National Environmental Satellite Data and Information Service for the NOAA 14 satellite launched December 30, 1994. It is based on careful validation of its operational predecessor (phase 1 algorithm), implemented for NOAA 14 in 1989. Both algorithms scale the upward satellite radiances in cloud-free conditions to aerosol optical thickness using an updated radiative transfer model of the ocean and atmosphere. Application of the phase 2 algorithm to three matchup Sun-photometer and satellite data sets, one with NOAA 9 in 1988 and two with NOAA 11 in 1989 and 1991, respectively, show systematic error is less than 10%, with a random error of sigma(sub tau) approx. equal 0.04. First results of tau(sup A)(sub SAT) retrievals from NOAA 14 using the phase 2 algorithm, and from checking its internal consistency, are presented. The potential two-channel (phase 3) algorithm for the retrieval of an aerosol size parameter, such as the Junge size distribution exponent, by adding either channel 2 (0.83 microns) from the current AVHRR instrument, or a 1.6-microns channel to be available on the Tropical Rainfall Measurement Mission and the NOAA-KLM satellites by 1997 is under investigation. The possibility of using this additional information in the retrieval of a more accurate estimate of aerosol optical thickness is being explored.

47 CFR 25.260 - Time sharing between DoD meteorological satellite systems and non-voice, non-geostationary...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Time sharing between DoD meteorological satellite systems and non-voice, non-geostationary satellite systems in the 400.15-401 MHz band. 25.260 Section 25.260 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES...

Environmental Testing Campaign and Verification of Satellite Deimos-2 at INTA

Science.gov (United States)

Hernandez, Daniel; Vazquez, Mercedes; Anon, Manuel; Olivo, Esperanza; Gallego, Pablo; Morillo, Pablo; Parra, Javier; Capraro; Luengo, Mar; Garcia, Beatriz; Villacorta, Pablo

2014-06-01

In this paper the environmental test campaign and verification of the DEIMOS-2 (DM2) satellite will be presented and described. DM2 will be ready for launch in 2014.Firstly, a short description of the satellite is presented, including its physical characteristics and intended optical performances. DEIMOS-2 is a LEO satellite for earth observation that will provide high resolution imaging services for agriculture, civil protection, environmental issues, disasters monitoring, climate change, urban planning, cartography, security and intelligence.Then, the verification and test campaign carried out on the SM and FM models at INTA is described; including Mechanical test for the SM and Climatic, Mechanical and Electromagnetic Compatibility tests for the FM. In addition, this paper includes Centre of Gravity and Moment of Inertia measurements for both models, and other verification activities carried out in order to ensure satellite's health during launch and its in orbit performance.

Time: A Critical Parameter in Satellite Navigation and Positioning ...

African Journals Online (AJOL)

The applications of space-borne satellites are increasing in many aspects of human endeavours; the most among them being the provision of guaranteed access to users of precise time and location services. An investigation was therefore carried out through a review process mechanism to determine the orbit parameter ...

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.

Video Streaming Transfer in a Smart Satellite Mobile Environment

OpenAIRE

Celandroni, Nedo; Davoli, Franco; Ferro, Erina; Gotta, Alberto

2009-01-01

In the near future, transportation media are likely to become "smart spaces", where sophisticated services are offered to the passengers. Among such services, we concentrate on video streaming provided on buses that move in urban, suburban, or highway environments. A contents' source utilizes a satellite DVB-S2 link for transmitting video streams to a bus, which, in its turn, relays it to its passengers' devices. A bus works in a smart mode taking advantage of the knowledge of the exact point...

Evaluating the Peruvian Rural Communication Services Project.

Science.gov (United States)

Mayo, John

1988-01-01

Reviews the Peruvian Rural Communication Services (PRCS) Project and outlines selected findings. Topics discussed include a brief description of Peru's economic and social conditions; satellite communication systems; audio teleconferencing; telephone service; planning and administration; research design features; data collection; and project…

A European Land Mobile Satellite System via EMS

Science.gov (United States)

Ananasso, Fulvio; Mistretta, Ignazio

1991-10-01

The paper analyzes the technical and market issues that influence the strategy of implementation of a Land Mobile Satellite System via the payload EMS (European Mobile System) embarked on ITALSAT F-2. The final goal is to determine services, network architecture, and added value chain that make LMSS via EMS profitable for a typical telecommunication company.

Effect of Ionosphere on Geostationary Communication Satellite Signals

Science.gov (United States)

Erdem, Esra; Arikan, Feza; Gulgonul, Senol

2016-07-01

ionosphere using IRI-Plas-G software. One of the outstanding features of IONOLAB-RAY is the opportunity of Global Ionospheric Map-Total Electron Content (GIM-TEC) assimilation. This feature enables more realistic representation of ionosphere, especially for the times when ionosphere deviates from the generalized models, such as during geomagnetic storms. This feature is critical to examine the effect of ionosphere on satellite signals under ionospheric storm conditions. In this study TURKSAT satellite data is used to compare the results of IONOLAB-RAY and evaluate the effect of ionosphere. TURKSAT is one of the world's leading companies providing all sorts of satellite communications through the satellites of TURKSAT as well as the other satellites. Providing services for voice, data, internet, TV, and radio broadcasting through the satellites across a wide area extending from Europe to Asia. The latest satellite of TURKSAT, namely Turksat 4B was launched on October 2015, before that various versions of TURKSAT satellites are launched since 1994. In the future enlargement of broadcasting area towards equatorial region is aimed, where the ionospheric anomalies and storms are highly expected. In the future this study can be applied to the satellite signals in equatorial regions and effects of ionosphere especially under storm conditions can be discussed. This study is supported by TUBITAK 114E541, 115E915 and Joint TUBITAK 114E092 and AS CR 14/001 projects.

Composite Broadcasting and Ranging via a Satellite Dual-Frequency MPPSK System

Directory of Open Access Journals (Sweden)

Yu Yao

2013-01-01

Full Text Available Since digital video broadcasting via satellite (DVB-S signals are “inefficient”, regarding the amount of information they convey on the bandwidth they occupy, a joint broadcasting and ranging system would constitute a unique platform for future digital video broadcasting satellite services effecting the essential tasks of satellite navigation system and direct to home (DTH services, in terms of both spectrum efficiency and cost effectiveness. In this paper, the design of dual frequency M-ary position phase shift keying (MPPSK system which is suitable for, respectively, performing both data transmission and range measurement is proposed. The approach is based on MPPSK modulation waveforms utilized in digital video broadcasting. In particular, requirements that allow for employing such signals for range measurements with high accuracy and high range are investigated. Also, the relationship between the frequency difference of dual frequency MPPSK system and range accuracy is discussed. Moreover, the selection of MPPSK modulation parameter for data rate and ranging is considered. In addition to theoretical considerations, the paper presents system simulations and measurement results of new systems, demonstrating the high spectral utilization of integrated broadcasting and ranging applications.

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

Competition in Telecoms-Implications for Universal Service and Employment

OpenAIRE

Petrazzini, Ben A.

1996-01-01

The author argues that competition in domestic telecommunications markets promotes both universal service and employment in developing countries. Thus, incumbent monopoly operators should be reformed. And since incumbents are subject to increasingly fierce international competition from callback services, Internet phone services, mobile satellite services, and global operators, this reform ...

Validation of Galileo orbits using SLR with a focus on satellites launched into incorrect orbital planes

Science.gov (United States)

Sośnica, Krzysztof; Prange, Lars; Kaźmierski, Kamil; Bury, Grzegorz; Drożdżewski, Mateusz; Zajdel, Radosław; Hadas, Tomasz

2018-02-01

The space segment of the European Global Navigation Satellite System (GNSS) Galileo consists of In-Orbit Validation (IOV) and Full Operational Capability (FOC) spacecraft. The first pair of FOC satellites was launched into an incorrect, highly eccentric orbital plane with a lower than nominal inclination angle. All Galileo satellites are equipped with satellite laser ranging (SLR) retroreflectors which allow, for example, for the assessment of the orbit quality or for the SLR-GNSS co-location in space. The number of SLR observations to Galileo satellites has been continuously increasing thanks to a series of intensive campaigns devoted to SLR tracking of GNSS satellites initiated by the International Laser Ranging Service. This paper assesses systematic effects and quality of Galileo orbits using SLR data with a main focus on Galileo satellites launched into incorrect orbits. We compare the SLR observations with respect to microwave-based Galileo orbits generated by the Center for Orbit Determination in Europe (CODE) in the framework of the International GNSS Service Multi-GNSS Experiment for the period 2014.0-2016.5. We analyze the SLR signature effect, which is characterized by the dependency of SLR residuals with respect to various incidence angles of laser beams for stations equipped with single-photon and multi-photon detectors. Surprisingly, the CODE orbit quality of satellites in the incorrect orbital planes is not worse than that of nominal FOC and IOV orbits. The RMS of SLR residuals is even lower by 5.0 and 1.5 mm for satellites in the incorrect orbital planes than for FOC and IOV satellites, respectively. The mean SLR offsets equal -44.9, -35.0, and -22.4 mm for IOV, FOC, and satellites in the incorrect orbital plane. Finally, we found that the empirical orbit models, which were originally designed for precise orbit determination of GNSS satellites in circular orbits, provide fully appropriate results also for highly eccentric orbits with variable linear

Evaluation of Future Internet Technologies for Processing and Distribution of Satellite Imagery

Science.gov (United States)

Becedas, J.; Perez, R.; Gonzalez, G.; Alvarez, J.; Garcia, F.; Maldonado, F.; Sucari, A.; Garcia, J.

2015-04-01

Satellite imagery data centres are designed to operate a defined number of satellites. For instance, difficulties when new satellites have to be incorporated in the system appear. This occurs because traditional infrastructures are neither flexible nor scalable. With the appearance of Future Internet technologies new solutions can be provided to manage large and variable amounts of data on demand. These technologies optimize resources and facilitate the appearance of new applications and services in the traditional Earth Observation (EO) market. The use of Future Internet technologies for the EO sector were validated with the GEO-Cloud experiment, part of the Fed4FIRE FP7 European project. This work presents the final results of the project, in which a constellation of satellites records the whole Earth surface on a daily basis. The satellite imagery is downloaded into a distributed network of ground stations and ingested in a cloud infrastructure, where the data is processed, stored, archived and distributed to the end users. The processing and transfer times inside the cloud, workload of the processors, automatic cataloguing and accessibility through the Internet are evaluated to validate if Future Internet technologies present advantages over traditional methods. Applicability of these technologies is evaluated to provide high added value services. Finally, the advantages of using federated testbeds to carry out large scale, industry driven experiments are analysed evaluating the feasibility of an experiment developed in the European infrastructure Fed4FIRE and its migration to a commercial cloud: SoftLayer, an IBM Company.

Orbit and clock determination of BDS regional navigation satellite system based on IGS M-GEX and WHU BETS tracking network

Science.gov (United States)

GENG, T.; Zhao, Q.; Shi, C.; Shum, C.; Guo, J.; Su, X.

2013-12-01

BeiDou Navigation Satellite System (BDS) began to provide the regional open service on December 27th 2012 and will provide the global open service by the end of 2020. Compared to GPS, the space segment of BDS Regional System consists of 5 Geostationary Earth Orbit satellites (GEO), 5 Inclined Geosynchronous Orbit satellites (IGSO) and 4 Medium Earth orbit (MEO) satellites. Since 2011, IGS Multiple-GNSS Experiment (M-GEX) focuses on tracking the newly available GNSS signals. This includes all signals from the modernized satellites of the GPS and GLONASS systems, as well as signals of the BDS, Galileo and QZSS systems. Up to now, BDS satellites are tracked by around 25 stations with a variety of different antennas and receivers from different GNSS manufacture communities in M-GEX network. Meanwhile, there are 17 stations with Unicore Communications Incorporation's GPS/BDS receivers in BeiDou Experimental Tracking Stations (BETS) network by Wuhan University. In addition, 5 BDS satellites have been tracking by the International Laser Ranging Service (ILRS). BDS performance is expected to be further studied by the GNSS communities. Following an introduction of the BDS system and above different tracking network, this paper discusses the achieved BDS characterization and performance assessment. Firstly, the BDS signal and measurement quality are analyzed with different antennas and receivers in detail compared to GPS. This includes depth of coverage for satellite observation, carrier-to-noise-density ratios, code noise and multipath, carrier phase errors. Secondly, BDS Precise Orbit Determination (POD) is processed. Different arc lengths and sets of orbit parameters are tested using Position And Navigation Data Analysis software (PANDA) which is developed at the Wuhan University. GEO, IGSO and MEO satellites orbit quality will be assessed using overlap comparison, 2-day orbit fit and external validations with Satellite Laser Range (SLR). Then BDS satellites are equipped

Current State of Art of Satellite Altimetry

Directory of Open Access Journals (Sweden)

Łyszkowicz Adam

2017-12-01

Full Text Available One of the fundamental problems of modern geodesy is precise definition of the gravitational field and its changes in time. This is essential in positioning and navigation, geo-physics, geodynamics, oceanography and other sciences related to the climate and Earth’s environment. One of the major sources of gravity data is satellite altimetry that provides gravity data with almost 75% surface of the Earth. Satellite altimetry also provides data to study local, regional and global geophysical processes, the geoid model in the areas of oceans and seas. This technique can be successfully used to study the ocean mean dynamic topography. The results of the investigations and possible products of altimetry will provide a good material for the GGOS (Global Geodetic Observing System and institutions of IAS (International Altimetry Service.

Land cover change of watersheds in Southern Guam from 1973 to 2001.

Science.gov (United States)

Wen, Yuming; Khosrowpanah, Shahram; Heitz, Leroy

2011-08-01

Land cover change can be caused by human-induced activities and natural forces. Land cover change in watershed level has been a main concern for a long time in the world since watersheds play an important role in our life and environment. This paper is focused on how to apply Landsat Multi-Spectral Scanner (MSS) satellite image of 1973 and Landsat Thematic Mapper (TM) satellite image of 2001 to determine the land cover changes of coastal watersheds from 1973 to 2001. GIS and remote sensing are integrated to derive land cover information from Landsat satellite images of 1973 and 2001. The land cover classification is based on supervised classification method in remote sensing software ERDAS IMAGINE. Historical GIS data is used to replace the areas covered by clouds or shadows in the image of 1973 to improve classification accuracy. Then, temporal land cover is utilized to determine land cover change of coastal watersheds in southern Guam. The overall classification accuracies for Landsat MSS image of 1973 and Landsat TM image of 2001 are 82.74% and 90.42%, respectively. The overall classification of Landsat MSS image is particularly satisfactory considering its coarse spatial resolution and relatively bad data quality because of lots of clouds and shadows in the image. Watershed land cover change in southern Guam is affected greatly by anthropogenic activities. However, natural forces also affect land cover in space and time. Land cover information and change in watersheds can be applied for watershed management and planning, and environmental modeling and assessment. Based on spatio-temporal land cover information, the interaction behavior between human and environment may be evaluated. The findings in this research will be useful to similar research in other tropical islands.

Spectral reflectance of five hardwood tree species in southern Indiana

Science.gov (United States)

Dale R. Weigel; J.C. Randolph

2013-01-01

The use of remote sensing to identify forest species has been ongoing since the launch of Landsat-1 using MSS imagery. The ability to separate hardwoods from conifers was accomplished by the 1980s. However, distinguishing individual hardwood species is more problematic due to similar spectral and phenological characteristics. With the launch of commercial satellites...

Web Based Rapid Mapping of Disaster Areas using Satellite Images, Web Processing Service, Web Mapping Service, Frequency Based Change Detection Algorithm and J-iView

Science.gov (United States)

Bandibas, J. C.; Takarada, S.

2013-12-01

Timely identification of areas affected by natural disasters is very important for a successful rescue and effective emergency relief efforts. This research focuses on the development of a cost effective and efficient system of identifying areas affected by natural disasters, and the efficient distribution of the information. The developed system is composed of 3 modules which are the Web Processing Service (WPS), Web Map Service (WMS) and the user interface provided by J-iView (fig. 1). WPS is an online system that provides computation, storage and data access services. In this study, the WPS module provides online access of the software implementing the developed frequency based change detection algorithm for the identification of areas affected by natural disasters. It also sends requests to WMS servers to get the remotely sensed data to be used in the computation. WMS is a standard protocol that provides a simple HTTP interface for requesting geo-registered map images from one or more geospatial databases. In this research, the WMS component provides remote access of the satellite images which are used as inputs for land cover change detection. The user interface in this system is provided by J-iView, which is an online mapping system developed at the Geological Survey of Japan (GSJ). The 3 modules are seamlessly integrated into a single package using J-iView, which could rapidly generate a map of disaster areas that is instantaneously viewable online. The developed system was tested using ASTER images covering the areas damaged by the March 11, 2011 tsunami in northeastern Japan. The developed system efficiently generated a map showing areas devastated by the tsunami. Based on the initial results of the study, the developed system proved to be a useful tool for emergency workers to quickly identify areas affected by natural disasters.

Oceanic turbidity and chlorophyll as inferred from ERTS-1 observations

Science.gov (United States)

Curran, R. J.

1973-01-01

Spectral signatures of phytoplankton and other obscuring effects are considered in order to determine how to best use satellite data. The results of this study were then used to analyze the spectral data obtained from the ERTS-1 multispectral scanner (MSS). The analyzed satellite data were finally compared with surface ship measurements of chlorophyll concentration. It was found that the effects of water turbidity on the multispectral imagery can be discriminated by rationing the two shortest wavelength channels so that the effect of phytoplankton is enhanced.

Efficient medium access control protocol for geostationary satellite systems

Institute of Scientific and Technical Information of China (English)

王丽娜; 顾学迈

2004-01-01

This paper proposes an efficient medium access control (MAC) protocol based on multifrequency-time division multiple access (MF-TDMA) for geostationary satellite systems deploying multiple spot-beams and onboard processing,which uses a method of random reservation access with movable boundaries to dynamically request the transmission slots and can transmit different types of traffic. The simulation results have shown that our designed MAC protocol can achieve a high bandwidth utilization, while providing the required quality of service (QoS) for each class of service.

Evaluation of SLAR and thematic mapper MSS data for forest cover mapping using computer-aided analysis techniques

Science.gov (United States)

Hoffer, R. M. (Principal Investigator); Knowlton, D. J.; Dean, M. E.

1981-01-01

Supervised and cluster block training statistics were used to analyze the thematic mapper simulation MSS data (both 1979 and 1980 data sets). Cover information classes identified on SAR imagery include: hardwood, pine, mixed pine hardwood, clearcut, pasture, crops, emergent crops, bare soil, urban, and water. Preliminary analysis of the HH and HV polarized SAR data indicate a high variance associated with each information class except for water and bare soil. The large variance for most spectral classes suggests that while the means might be statistically separable, an overlap may exist between the classes which could introduce a significant classification error. The quantitative values of many cover types are much larger on the HV polarization than on the HH, thereby indicating the relative nature of the digitized data values. The mean values of the spectral classes in the areas with larger look angles are greater than the means of the same cover type in other areas having steeper look angles. Difficulty in accurately overlaying the dual polarization of the SAR data was resolved.

Evaluación de un programa de maestría en Educación a través de la MSS

Directory of Open Access Journals (Sweden)

José Roberto Ramos Mendoza

2016-05-01

Full Text Available La evaluación de los programas de posgrado es una necesidad para su adecuación a las demandas sociales y laborales. El objetivo fue evaluar el Programa de Maestría en Administración en Gestión y Desarrollo de la Educación de la Escasto-IPN, a través de la metodología de los sistemas suaves (MSS, que facilitó un pensamiento integral de los actores intervinientes en el problema, haciendo análisis particular mediante la nemotecnia Catwoe, con un resultado integral conforme los criterios PNPC-CONACyT. Se aplicaron tres cuestionarios validados. Un resultado destacado es la necesidad de formación de cuadros directivos en ámbitos como inteligencia emocional, normatividad, ética y transparencia. En conclusión, el posgrado adquiere un nuevo compromiso: dejar de lado la mercantilización de la educación y convertirse en generador de personas críticas, analíticas y sobre todo propositivas que a su vez sean generadoras de innovaciones en pro de la calidad educativa. AbstractThe assessment of graduate programs is a necessity for adaptation to social and labor demands. The objective was to evaluate the MBA program in Management and Development of Education of the ESCASTO-IPN, through the Soft Systems Methodology (MSS, it provided a comprehensive thinking of the actors involved in the issue, doing CATWOE particular analysis by mnemonic, achieving a comprehensive income based on the PNPC criteria - CONACyT. Three questionnaires were applied validated. A prominent result is the need for training of cadres in areas such as: emotional intelligence, regulation, ethics and transparency. In conclusion, the graduate acquires a new commitment, neglecting the commodification of education and become generator critics, analytical and proactive especially in turn are generating innovations in favor of quality education.

Use of satellite images for the monitoring of water systems

Science.gov (United States)

Hillebrand, Gudrun; Winterscheid, Axel; Baschek, Björn; Wolf, Thomas

2015-04-01

Satellite images are a proven source of information for monitoring ecological indicators in coastal waters and inland river systems. This potential of remote sensing products was demonstrated by recent research projects (e.g. EU-funded project Freshmon - www.freshmon.eu) and other activities by national institutions. Among indicators for water quality, a particular focus was set on the temporal and spatial dynamics of suspended particulate matter (SPM) and Chlorophyll-a (Chl-a). The German Federal Institute of Hydrology (BfG) was using the Weser and Elbe estuaries as test cases to compare in-situ measurements with results obtained from a temporal series of automatically generated maps of SPM distributions based on remote sensing data. Maps of SPM and Chl-a distributions in European inland rivers and alpine lakes were generated by the Freshmon Project. Earth observation based products are a valuable source for additional data that can well supplement in-situ monitoring. For 2015, the BfG and the Institute for Lake Research of the State Institute for the Environment, Measurements and Nature Conservation of Baden-Wuerttemberg, Germany (LUBW) are in the process to start implementing an operational service for monitoring SPM and Chl-a based on satellite images (Landsat 7 & 8, Sentinel 2, and if required other systems with higher spatial resolution, e.g. Rapid Eye). In this 2-years project, which is part of the European Copernicus Programme, the operational service will be set up for - the inland rivers of Rhine and Elbe - the North Sea estuaries of Elbe, Weser and Ems. Furthermore - Lake Constance and other lakes located within the Federal State of Baden-Wuerttemberg. In future, the service can be implemented for other rivers and lakes as well. Key feature of the project is a data base that holds the stock of geo-referenced maps of SPM and Chl-a distributions. Via web-based portals (e.g. GGInA - geo-portal of the BfG; UIS - environmental information system of the

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

Development of a demand assignment/TDMA system for international business satellite communications

Science.gov (United States)

Nohara, Mitsuo; Takeuchi, Yoshio; Takahata, Fumio; Hirata, Yasuo; Yamazaki, Yoshiharu

An experimental IBS (international business satellite) communications system based on a demand assignment and TDMA (time-division multiple-access) operation has been developed. The system utilizes a limited satellite resource efficiently and provides various kinds of ISDN services totally. A discussion is presented of the IBS network configurations suitable to international communications and describes the developed communications system from the viewpoint of the hardware and software implementation. The performance in terms of the transmission quality and call processing is also demonstrated.

Use of negotiated rulemaking in developing technical rules for low-Earth orbit mobile satellite systems

Science.gov (United States)

Taylor, Leslie A.

Technical innovations have converged with the exploding market demand for mobile telecommunications to create the impetus for low-earth orbit (LEO) communications satellite systems. The so-called 'Little LEO's' propose use of VHF and UHF spectrum to provide position - location and data messaging services. The so-called 'Big LEO's' propose to utilize the RDSS bands to provide voice and data services. In the United States, several applications were filed with the U.S. Federal Communications Commission (FCC) to construct and operate these mobile satellite systems. To enable the prompt introduction of such new technology services, the FCC is using innovative approaches to process the applications. Traditionally, when the FCC is faced with 'mutually exclusive' applications, e.g. a grant of one would preclude a grant of the others, it uses selection mechanisms such as comparative hearings or lotteries. In the case of the LEO systems, the FCC has sought to avoid these time-consuming approaches by using negotiated rulemakings. The FCC's objective is to enable the multiple applicants and other interested parties to agree on technical and service rules which will enable the grant of all qualified applications. With regard to the VHF/UHF systems, the Advisory Committee submitted a consensus report to the FCC. The process for the systems operating in the bands above 1 GHz involved more parties and more issues but still provided the FCC useful technical information to guide the adoption of rules for the new mobile satellite service.

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.

GEARS: An Enterprise Architecture Based On Common Ground Services

Science.gov (United States)

Petersen, S.

2014-12-01

Earth observation satellites collect a broad variety of data used in applications that range from weather forecasting to climate monitoring. Within NOAA the National Environmental Satellite Data and Information Service (NESDIS) supports these applications by operating satellites in both geosynchronous and polar orbits. Traditionally NESDIS has acquired and operated its satellites as stand-alone systems with their own command and control, mission management, processing, and distribution systems. As the volume, velocity, veracity, and variety of sensor data and products produced by these systems continues to increase, NESDIS is migrating to a new concept of operation in which it will operate and sustain the ground infrastructure as an integrated Enterprise. Based on a series of common ground services, the Ground Enterprise Architecture System (GEARS) approach promises greater agility, flexibility, and efficiency at reduced cost. This talk describes the new architecture and associated development activities, and presents the results of initial efforts to improve product processing and distribution.

12-bit 32 channel 500 MS/s low-latency ADC for particle accelerators real-time control

Science.gov (United States)

Karnitski, Anton; Baranauskas, Dalius; Zelenin, Denis; Baranauskas, Gytis; Zhankevich, Alexander; Gill, Chris

2017-09-01

Particle beam control systems require real-time low latency digital feedback with high linearity and dynamic range. Densely packed electronic systems employ high performance multichannel digitizers causing excessive heat dissipation. Therefore, low power dissipation is another critical requirement for these digitizers. A described 12-bit 500 MS/s ADC employs a sub-ranging architecture based on a merged sample & hold circuit, a residue C-DAC and a shared 6-bit flash core ADC. The core ADC provides a sequential coarse and fine digitization featuring a latency of two clock cycles. The ADC is implemented in a 28 nm CMOS process and consumes 4 mW of power per channel from a 0.9 V supply (interfacing and peripheral circuits are excluded). Reduced power consumption and small on-chip area permits the implementation of 32 ADC channels on a 10.7 mm2 chip. The ADC includes a JESD204B standard compliant output data interface operated at the 7.5 Gbps/ch rate. To minimize the data interface related time latency, a special feature permitting to bypass the JESD204B interface is built in. DoE Phase I Award Number: DE-SC0017213.

Optical intersatellite links - Application to commercial satellite communications

Science.gov (United States)

Paul, D.; Faris, F.; Garlow, R.; Inukai, T.; Pontano, B.; Razdan, R.; Ganz, Aura; Caudill, L.

1992-01-01

Application of optical intersatellite links for commercial satellite communications services is addressed in this paper. The feasibility of commercialization centers around basic issues such as the need and derived benefits, implementation complexity and overall cost. In this paper, commercialization of optical ISLs is assessed in terms of the services provided, systems requirements and feasibility of appropriate technology. Both long- and short-range ISLs for GEO-GEO, GEO-LEO and LEO applications are considered. Impact of systems requirements on the payload design and use of advanced technology in reducing its mass, power, and volume requirements are discussed.

Satellite -Based Networks for U-Health & U-Learning

Science.gov (United States)

Graschew, G.; Roelofs, T. A.; Rakowsky, S.; Schlag, P. M.

2008-08-01

The use of modern Information and Communication Technologies (ICT) as enabling tools for healthcare services (eHealth) introduces new ways of creating ubiquitous access to high-level medical care for all, anytime and anywhere (uHealth). Satellite communication constitutes one of the most flexible methods of broadband communication offering high reliability and cost-effectiveness of connections meeting telemedicine communication requirements. Global networks and the use of computers for educational purposes stimulate and support the development of virtual universities for e-learning. Especially real-time interactive applications can play an important role in tailored and personalised services.

Global Precipitation Measurement (GPM) Mission Products and Services at the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC)

Science.gov (United States)

Liu, Zhong; Ostrenga, D.; Vollmer, B.; Deshong, B.; Greene, M.; Teng, W.; Kempler, S. J.

2015-01-01

On February 27, 2014, the NASA Global Precipitation Measurement (GPM) mission was launched to provide the next-generation global observations of rain and snow (http:pmm.nasa.govGPM). The GPM mission consists of an international network of satellites in which a GPM Core Observatory satellite carries both active and passive microwave instruments to measure precipitation and serve as a reference standard, to unify precipitation measurements from a constellation of other research and operational satellites. The NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) hosts and distributes GPM data within the NASA Earth Observation System Data Information System (EOSDIS). The GES DISC is home to the data archive for the GPM predecessor, the Tropical Rainfall Measuring Mission (TRMM). Over the past 16 years, the GES DISC has served the scientific as well as other communities with TRMM data and user-friendly services. During the GPM era, the GES DISC will continue to provide user-friendly data services and customer support to users around the world. GPM products currently and to-be available include the following: 1. Level-1 GPM Microwave Imager (GMI) and partner radiometer products. 2. Goddard Profiling Algorithm (GPROF) GMI and partner products. 3. Integrated Multi-satellitE Retrievals for GPM (IMERG) products. (early, late, and final)A dedicated Web portal (including user guides, etc.) has been developed for GPM data (http:disc.sci.gsfc.nasa.govgpm). Data services that are currently and to-be available include Google-like Mirador (http:mirador.gsfc.nasa.gov) for data search and access; data access through various Web services (e.g., OPeNDAP, GDS, WMS, WCS); conversion into various formats (e.g., netCDF, HDF, KML (for Google Earth), ASCII); exploration, visualization, and statistical online analysis through Giovanni (http:giovanni.gsfc.nasa.gov); generation of value-added products; parameter and spatial subsetting; time aggregation; regridding; data

Global Precipitation Measurement (GPM) Mission Products and Services at the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC)

Science.gov (United States)

Ostrenga, D.; Liu, Z.; Vollmer, B.; Teng, W. L.; Kempler, S. J.

2014-12-01

On February 27, 2014, the NASA Global Precipitation Measurement (GPM) mission was launched to provide the next-generation global observations of rain and snow (http://pmm.nasa.gov/GPM). The GPM mission consists of an international network of satellites in which a GPM "Core Observatory" satellite carries both active and passive microwave instruments to measure precipitation and serve as a reference standard, to unify precipitation measurements from a constellation of other research and operational satellites. The NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) hosts and distributes GPM data within the NASA Earth Observation System Data Information System (EOSDIS). The GES DISC is home to the data archive for the GPM predecessor, the Tropical Rainfall Measuring Mission (TRMM). Over the past 16 years, the GES DISC has served the scientific as well as other communities with TRMM data and user-friendly services. During the GPM era, the GES DISC will continue to provide user-friendly data services and customer support to users around the world. GPM products currently and to-be available include the following: Level-1 GPM Microwave Imager (GMI) and partner radiometer products Goddard Profiling Algorithm (GPROF) GMI and partner products Integrated Multi-satellitE Retrievals for GPM (IMERG) products (early, late, and final) A dedicated Web portal (including user guides, etc.) has been developed for GPM data (http://disc.sci.gsfc.nasa.gov/gpm). Data services that are currently and to-be available include Google-like Mirador (http://mirador.gsfc.nasa.gov/) for data search and access; data access through various Web services (e.g., OPeNDAP, GDS, WMS, WCS); conversion into various formats (e.g., netCDF, HDF, KML (for Google Earth), ASCII); exploration, visualization, and statistical online analysis through Giovanni (http://giovanni.gsfc.nasa.gov); generation of value-added products; parameter and spatial subsetting; time aggregation; regridding

Mapping Impervious Surface Expansion using Medium-resolution Satellite Image Time Series: A Case Study in the Yangtze River Delta, China

Science.gov (United States)

Gao, Feng; DeColstoun, Eric Brown; Ma, Ronghua; Weng, Qihao; Masek, Jeffrey G.; Chen, Jin; Pan, Yaozhong; Song, Conghe

2012-01-01

Cities have been expanding rapidly worldwide, especially over the past few decades. Mapping the dynamic expansion of impervious surface in both space and time is essential for an improved understanding of the urbanization process, land-cover and land-use change, and their impacts on the environment. Landsat and other medium-resolution satellites provide the necessary spatial details and temporal frequency for mapping impervious surface expansion over the past four decades. Since the US Geological Survey opened the historical record of the Landsat image archive for free access in 2008, the decades-old bottleneck of data limitation has gone. Remote-sensing scientists are now rich with data, and the challenge is how to make best use of this precious resource. In this article, we develop an efficient algorithm to map the continuous expansion of impervious surface using a time series of four decades of medium-resolution satellite images. The algorithm is based on a supervised classification of the time-series image stack using a decision tree. Each imerpervious class represents urbanization starting in a different image. The algorithm also allows us to remove inconsistent training samples because impervious expansion is not reversible during the study period. The objective is to extract a time series of complete and consistent impervious surface maps from a corresponding times series of images collected from multiple sensors, and with a minimal amount of image preprocessing effort. The approach was tested in the lower Yangtze River Delta region, one of the fastest urban growth areas in China. Results from nearly four decades of medium-resolution satellite data from the Landsat Multispectral Scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper plus (ETM+) and China-Brazil Earth Resources Satellite (CBERS) show a consistent urbanization process that is consistent with economic development plans and policies. The time-series impervious spatial extent maps derived

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.

Public Service Telecommunications: PEACESAT.

Science.gov (United States)

Okamura, Norman H.; Mukaida, Lori Van Dusen

1996-01-01

Describes the Pan-Pacific Education and Communication Experiments by Satellite (PEACESAT), a public service telecommunication program developed to facilitate the use of telecommunications and information technologies. Highlights include the historical development; digital capabilities; cooperation and collaboration with users, government, and…

International Telecommunications Satellite Organization (INTELSAT) Agreement Between the United States of American and Other Governments and Operating Agreement.

Science.gov (United States)

Department of State, Washington, DC.

The INTELSAT (International Telecommunications Satellite) agreement was reached because of the desirability of continuing the development of a telecommunications satellite system. INTELSAT's aim was to achieve a single global commercial system as part of an improved global telecommunications network which will provide expanded services to all…

Video Streaming Transfer in a Smart Satellite Mobile Environment

Directory of Open Access Journals (Sweden)

Nedo Celandroni

2009-01-01

satellite link for transmitting video streams to a bus, where they are relayed to passengers' devices. We say that a bus works in smart mode if it takes advantage of the knowledge of the exact points where fixed obstacles will prevent receiving the satellite signal for a certain time period. This information is sent to the hub via a return channel. The hub, in its turn, suspends the transmissions to that specific bus for the given time interval, thus avoiding information losses and unnecessary bandwidth occupation. Buffering video packets, without any quality of service (QoS degradation, seamlessly compensates channel blockages up to a given duration. We determine the most appropriate transmission parameters for video streaming with good video QoS in a mobile satellite environment; moreover, we evaluate how “smart” the system can be in terms of bandwidth saving, by comparing it with the situation where the bus does not exploit the description of its route, still maintaining the same QoS requirements.

Debris mitigation measures by satellite design and operational methods - Findings from the DLR space debris End-to-End Service

Science.gov (United States)

Sdunnus, H.; Beltrami, P.; Janovsky, R.; Koppenwallner, G.; Krag, H.; Reimerdes, H.; Schäfer, F.

Debris Mitigation has been recognised as an issue to be addressed by the space faring nations around the world. Currently, there are various activities going on, aiming at the establishment of debris mitigation guidelines on various levels, reaching from the UN down to national space agencies. Though guidelines established on the national level already provide concrete information how things should be done (rather that specifying what should be done or providing fundamental principles) potential users of the guidelines will still have the need to explore the technical, management, and financial implications of the guidelines for their projects. Those questions are addressed by the so called "Space Debris End-to-End Service" project, which has been initiated as a national initiative of the German Aerospace Centre (DLR). Based on a review of already existing mitigation guidelines or guidelines under development and following an identification of needs from a circle of industrial users the "End-to-End Service Gu idelines" have been established for designer and operators of spacecraft. The End-to-End Service Guidelines are based on requirements addressed by the mitigation guidelines and provide recommendations how and when the technical consideration of the mitigation guidelines should take place. By referencing requirements from the mitigation guidelines, the End-to-End Service Guidelines address the consideration of debris mitigation measures by spacecraft design and operational measures. This paper will give an introduction to the End-to-End Service Guidelines. It will focus on the proposals made for mitigation measures by the S/C system design, i.e. on protective design measures inside the spacecraft and on design measures, e.g. innovative protective (shielding) systems. Furthermore, approaches on the analytical optimisation of protective systems will be presented, aiming at the minimisation of shield mass under conservation of the protective effects. On the

Fair-share scheduling algorithm for a tertiary storage system

International Nuclear Information System (INIS)

Jakl, Pavel; Sumbera, Michal; Lauret, Jerome

2010-01-01

Any experiment facing Peta bytes scale problems is in need for a highly scalable mass storage system (MSS) to keep a permanent copy of their valuable data. But beyond the permanent storage aspects, the sheer amount of data makes complete data-set availability onto live storage (centralized or aggregated space such as the one provided by Scalla/Xrootd) cost prohibitive implying that a dynamic population from MSS to faster storage is needed. One of the most challenging aspects of dealing with MSS is the robotic tape component. If a robotic system is used as the primary storage solution, the intrinsically long access times (latencies) can dramatically affect the overall performance. To speed the retrieval of such data, one could organize the requests according to criterion with an aim to deliver maximal data throughput. However, such approaches are often orthogonal to fair resource allocation and a trade-off between quality of service, responsiveness and throughput is necessary for achieving an optimal and practical implementation of a truly faire-share oriented file restore policy. Starting from an explanation of the key criterion of such a policy, we will present evaluations and comparisons of three different MSS file restoration algorithms which meet fair-share requirements, and discuss their respective merits. We will quantify their impact on a typical file restoration cycle for the RHIC/STAR experimental setup and this, within a development, analysis and production environment relying on a shared MSS service [1].

47 CFR 25.158 - Consideration of GSO-like satellite applications.

Science.gov (United States)

2010-10-01

... directional antennas. Examples of GSO-like satellite systems are those which use earth stations with antennas... contiguous bandwidth in both the uplink and downlink band. Each licensee's bandwidth selection shall not... selection. (e) Services offered pursuant to a GSO-like license in a frequency band granted before the...

A comparison of Frequency Domain Multiple Access (FDMA) and Time Domain Multiple Access (TDMA) approaches to satellite service for low data rate Earth stations

Science.gov (United States)

Stevens, G.

1983-01-01

A technological and economic assessment is made of providing low data rate service to small earth stations by satellite at Ka-band. Various Frequency Domain Multiple Access (FDMA) and Time Domain Multiple Access (TDMA) scenarios are examined and compared on the basis of cost to the end user. Very small stations (1 to 2 meters in diameter) are found not to be viable alternatives to available terrestrial services. However, medium size (3 to 5 meters) earth stations appear to be very competitive if a minimum throughput of about 1.5 Mbs is maintained. This constrains the use of such terminals to large users and shared use by smaller users. No advantage was found to the use of FDMA. TDMA had a slight advantage from a total system viewpoint and a very significant advantage in the space segment (about 1/3 the required payload weight for an equivalent capacity).

Operational Estimation of Accumulated Precipitation using Satellite Observation, by Eumetsat Satellite Application facility in Support to Hydrology (H-SAF Consortium).

Science.gov (United States)

di Diodato, A.; de Leonibus, L.; Zauli, F.; Biron, D.; Melfi, D.

2009-04-01

Operational Estimation of Accumulated Precipitation using Satellite Observation, by Eumetsat Satellite Application facility in Support to Hydrology (H-SAF Consortium). Cap. Attilio DI DIODATO(*), T.Col. Luigi DE LEONIBUS(*), T.Col Francesco ZAULI(*), Cap. Daniele BIRON(*), Ten. Davide Melfi(*) Satellite Application Facilities (SAFs) are specialised development and processing centres of the EUMETSAT Distributed Ground Segment. SAFs process level 1b data from meteorological satellites (geostationary and polar ones) in conjunction with all other relevant sources of data and appropriate models to generate services and level 2 products. Each SAF is a consortium of EUMETSAT European partners lead by a host institute responsible for the management of the complete SAF project. The Meteorological Service of Italian Air Force is the host Institute for the Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF). HSAF has the commitment to develop and to provide, operationally after 2010, products regarding precipitation, soil moisture and snow. HSAF is going to provide information on error structure of its products and validation of the products via their impacts into Hydrological models. To that purpose it has been structured a specific subgroups. Accumulated precipitation is computed by temporal integration of the instantaneous rain rate achieved by the blended LEO/MW and GEO/IR precipitation rate products generated by Rapid Update method available every 15 minutes. The algorithm provides four outputs, consisting in accumulated precipitation in 3, 6, 12 and 24 hours, delivered every 3 hours at the synoptic hours. These outputs are our precipitation background fields. Satellite estimates can cover most of the globe, however, they suffer from errors due to lack of a direct relationship between observation parameters and precipitation, the poor sampling and algorithm imperfections. For this reason the 3 hours accumulated precipitation is

Research-related intercultural higher education in satellite geodesy

Science.gov (United States)

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

2009-04-01

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

A Web Service Tool (SOAR) for the Dynamic Generation of L1 Grids of Coincident AIRS, AMSU and MODIS Satellite Sounding Radiance Data for Climate Studies

Science.gov (United States)

Halem, M.; Yesha, Y.; Tilmes, C.; Chapman, D.; Goldberg, M.; Zhou, L.

2007-05-01

Three decades of Earth remote sensing from NASA, NOAA and DOD operational and research satellites carrying successive generations of improved atmospheric sounder instruments have resulted in petabytes of radiance data with varying spatial and spectral resolutions being stored at different data archives in various data formats by the respective agencies. This evolution of sounders and the diversities of these archived data sets have led to data processing obstacles limiting the science community from readily accessing and analyzing such long-term climate data records. We address this problem by the development of a web based Service Oriented Atmospheric Radiance (SOAR) system built on the SOA paradigm that makes it practical for the science community to dynamically access, manipulate and generate long term records of L1 pre-gridded sounding radiances of coincident multi-sensor data for regions specified according to user chosen criteria. SOAR employs a modification of the standard Client Server interactions that allows users to represent themselves directly to the Process Server through their own web browsers. The browser uses AJAX to request Javascript libraries and DHTML interfaces that define the possible client interactions and communicates the SOAP messages to the Process server allowing for dynamic web dialogs with the user to take place on the fly. The Process Server is also connected to an underlying high performance compute cluster and storage system which provides much of the data processing capabilities required to service the client requests. The compute cluster employs optical communications to NOAA and NASA for accessing the data and under the governance of the Process Server invokes algorithms for on-demand spatial, temporal, and spectral gridding. Scientists can choose from a variety of statistical averaging techniques for compositing satellite observed sounder radiances from the AIRS, AMSU or MODIS instruments to form spatial-temporal grids for

Satellite and terrestrial radio positioning techniques a signal processing perspective

CERN Document Server

Dardari, Davide; Falletti, Emanuela

2014-01-01

* The first book to combine satellite and terrestrial positioning techniques - vital for the understanding and development of new technologies * Written and edited by leading experts in the field, with contributors belonging to the European Commission's FP7 Network of Excellence NEWCOM++ Applications to a wide range of fields, including sensor networks, emergency services, military use, location-based billing, location-based advertising, intelligent transportation, and leisure Location-aware personal devices and location-based services have become ever more prominent in the past few years

A digital simulation of message traffic for natural disaster warning communications satellite

Science.gov (United States)

Hein, G. F.; Stevenson, S. M.

1972-01-01

Various types of weather communications are required to alert industries and the general public about the impending occurrence of tornados, hurricanes, snowstorms, floods, etc. A natural disaster warning satellite system has been proposed for meeting the communications requirements of the National Oceanic and Atmospheric Administration. Message traffic for a communications satellite was simulated with a digital computer in order to determine the number of communications channels to meet system requirements. Poisson inputs are used for arrivals and an exponential distribution is used for service.

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.

R&D of a Next Generation LEO System for Global Multimedia Mobile Satellite Communications

Science.gov (United States)

Morikawa, E.; Motoyoshi, S.; Koyama, Y.; Suzuki, R.; Yasuda, Y.

2002-01-01

Next-generation LEO System Research Center (NeLS) was formed in the end of 1997 as a research group under the Telecommunications Advancement Organization of Japan, in cooperation with the telecommunications operators, manufacturers, universities and governmental research organization. The aim of this project is to develop new technology for global multimedia mobile satellite communications services with a user data rate around 2Mbps for handy terminals. component of the IMT-2000, and the second generation of the big-LEO systems. In prosecuting this project, two-phase approach, phase 1 and phase 2, is considered. Phase 1 is the system definition and development of key technologies. In Phase 2, we plan to verify the developed technology in Phase 1 on space. From this year we shifted the stage to Phase 2, and are now developing the prototype of on-board communication systems for flight tests, which will be planed at around 2006. The satellite altitude is assumed to be 1200 km in order to reduce the number of satellites, to avoid the Van Allen radiation belts and to increase the minimum elevation angle. Ten of the circular orbits with 55 degree of inclination are selected to cover the earth surface from -70 to 70 degree in latitude. 12 satellites are positioned at regular intervals in each orbit. In this case, the minimum elevation angle from the user terminal can be keep more than 20 degree for the visibility of the satellite, and 15 degree for simultaneous visibility of two satellites. Then, NeLS Research Center was focusing on the development of key technologies as the phase 1 project. Four kinds of key technologies; DBF satellite antenna, optical inter-satellite link system, satellite network technology with on-board ATM switch and variable rate modulation were selected. Satellite Antenna Technology: Development of on-board direct radiating active phased array antenna with digital beam forming technology would be one of the most important breakthroughs for the

Next-Generation NASA Earth-Orbiting Relay Satellites: Fusing Optical and Microwave Communications

Science.gov (United States)

Israel, David J.; Shaw, Harry

2018-01-01

NASA is currently considering architectures and concepts for the generation of relay satellites that will replace the Tracking and Data Relay Satellite (TDRS) constellation, which has been flying since 1983. TDRS-M, the last of the second TDRS generation, launched in August 2017, extending the life of the TDRS constellation beyond 2030. However, opportunities exist to re-engineer the concepts of geosynchronous Earth relay satellites. The needs of the relay satellite customers have changed dramatically over the last 34 years since the first TDRS launch. There is a demand for greater bandwidth as the availability of the traditional RF spectrum for space communications diminishes and the demand for ground station access grows. The next generation of NASA relay satellites will provide for operations that have factored in these new constraints. In this paper, we describe a heterogeneous constellation of geosynchronous relay satellites employing optical and RF communications. The new constellation will enable new optical communications services formed by user-to-space relay, space relay-to-space relay and space relay-to-ground links. It will build upon the experience from the Lunar Laser Communications Demonstration from 2013 and the Laser Communications Relay Demonstration to be launched in 2019.Simultaneous to establishment of the optical communications space segment, spacecraft in the TDRS constellation will be replaced with RF relay satellites with targeted subsets of the TDRS capabilities. This disaggregation of the TDRS service model will allow for flexibility in replenishing the needs of legacy users as well as addition of new capabilities for future users. It will also permit the U.S. government access to launch capabilities such as rideshare and to hosted payloads that were not previously available.In this paper, we also explore how the next generation of Earth relay satellites provides a significant boost in the opportunities for commercial providers to the

Next-Generation NASA Earth-Orbiting Relay Satellites: Fusing Microwave and Optical Communications

Science.gov (United States)

Israel, David J.

2018-01-01

NASA is currently considering architectures and concepts for the generation of relay satellites that will replace the Tracking and Data Relay Satellite (TDRS) constellation, which has been flying since 1983. TDRS-M, the last of the second TDRS generation, launched in August 2017, extending the life of the TDRS constellation beyond 2030. However, opportunities exist to re-engineer the concepts of geosynchronous Earth relay satellites. The needs of the relay satellite customers have changed dramatically over the last 34 years since the first TDRS launch. There is a demand for greater bandwidth as the availability of the traditional RF spectrum for space communications diminishes and the demand for ground station access grows. The next generation of NASA relay satellites will provide for operations that have factored in these new constraints. In this paper, we describe a heterogeneous constellation of geosynchronous relay satellites employing optical and RF communications. The new constellation will enable new optical communications services formed by user-to-space relay, space relay-to-space relay and space relay-to-ground links. It will build upon the experience from the Lunar Laser Communications Demonstration from 2013 and the Laser Communications Relay Demonstration to be launched in 2019.Simultaneous to establishment of the optical communications space segment, spacecraft in the TDRS constellation will be replaced with RF relay satellites with targeted subsets of the TDRS capabilities. This disaggregation of the TDRS service model will allow for flexibility in replenishing the needs of legacy users as well as addition of new capabilities for future users. It will also permit the U.S. government access to launch capabilities such as rideshare and to hosted payloads that were not previously available. In this paper, we also explore how the next generation of Earth relay satellites provides a significant boost in the opportunities for commercial providers to the

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....

Development of the European Small Geostationary Satellite SGEO

Science.gov (United States)

Lübberstedt, H.; Schneider, A.; Schuff, H.; Miesner, Th.; Winkler, A.

2008-08-01

The SGEO product portfolio, ranging from Satellite platform delivery up to in-orbit delivery of a turnkey system including satellite and ground control station, is designed for applications ranging from TV Broadcast to multimedia applications, Internet access, mobile or fixed services in a wide range of frequency bands. Furthermore, Data Relay missions such as the European Data Relay Satellite (EDRS) as well as other institutional missions are targeted. Key design features of the SGEO platform are high flexibility and modularity in order to accommodate a very wide range of future missions, a short development time below two years and the objective to build the system based on ITAR free subsystems and components. The system will provide a long lifetime of up to 15 years in orbit operations with high reliability. SGEO is the first European satellite to perform all orbit control tasks solely by electrical propulsion (EP). This design provides high mass efficiency and the capability for direct injection into geostationary orbit without chemical propulsion (CP). Optionally, an Apogee Engine Module based on CP will provide the perigee raising manoeuvres in case of a launch into geostationary transfer orbit (GTO). This approach allows an ideal choice out of a wide range of launcher candidates in dependence of the required payload capacity. SGEO will offer to the market a versatile and high performance satellite system with low investment risk for the customer and a short development time. This paper provides an overview of the SGEO system key features and the current status of the SGEO programme.

Interconnection of Broadband Islands via Satellite-Experiments on the Race II Catalyst Project

National Research Council Canada - National Science Library

Sun, Z

1996-01-01

.... The purpose of the project was to develop an ATM satellite link for the future B-ISDN services, particularly for the interconnections of the ATM testbeds which are in the form of broadband islands...

Analysis on Sealing Reliability of Bolted Joint Ball Head Component of Satellite Propulsion System

Science.gov (United States)

Guo, Tao; Fan, Yougao; Gao, Feng; Gu, Shixin; Wang, Wei

2018-01-01

Propulsion system is one of the important subsystems of satellite, and its performance directly affects the service life, attitude control and reliability of the satellite. The Paper analyzes the sealing principle of bolted joint ball head component of satellite propulsion system and discuss from the compatibility of hydrazine anhydrous and bolted joint ball head component, influence of ground environment on the sealing performance of bolted joint ball heads, and material failure caused by environment, showing that the sealing reliability of bolted joint ball head component is good and the influence of above three aspects on sealing of bolted joint ball head component can be ignored.

Above the cloud computing: applying cloud computing principles to create an orbital services model

Science.gov (United States)

Straub, Jeremy; Mohammad, Atif; Berk, Josh; Nervold, Anders K.

2013-05-01

Large satellites and exquisite planetary missions are generally self-contained. They have, onboard, all of the computational, communications and other capabilities required to perform their designated functions. Because of this, the satellite or spacecraft carries hardware that may be utilized only a fraction of the time; however, the full cost of development and launch are still bone by the program. Small satellites do not have this luxury. Due to mass and volume constraints, they cannot afford to carry numerous pieces of barely utilized equipment or large antennas. This paper proposes a cloud-computing model for exposing satellite services in an orbital environment. Under this approach, each satellite with available capabilities broadcasts a service description for each service that it can provide (e.g., general computing capacity, DSP capabilities, specialized sensing capabilities, transmission capabilities, etc.) and its orbital elements. Consumer spacecraft retain a cache of service providers and select one utilizing decision making heuristics (e.g., suitability of performance, opportunity to transmit instructions and receive results - based on the orbits of the two craft). The two craft negotiate service provisioning (e.g., when the service can be available and for how long) based on the operating rules prioritizing use of (and allowing access to) the service on the service provider craft, based on the credentials of the consumer. Service description, negotiation and sample service performance protocols are presented. The required components of each consumer or provider spacecraft are reviewed. These include fully autonomous control capabilities (for provider craft), a lightweight orbit determination routine (to determine when consumer and provider craft can see each other and, possibly, pointing requirements for craft with directional antennas) and an authentication and resource utilization priority-based access decision making subsystem (for provider craft

The Design and Implementation of the Petite Amateur Naval Satellite (PANSAT) User Service Software

National Research Council Canada - National Science Library

Hunter, George

1998-01-01

... or eventually replace the existing military satellite communications architecture. While more than eight years of work has gone into the project, most of the nearly sixty theses thus far have dealt with hardware development...

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.

Emerging Technologies: Small Satellite and Associated TPED

Science.gov (United States)

Zitz, R.

2014-09-01

The 2010 National Space Policy directs the U.S. space community, comprised of the Department of Defense, Intelligence Community, Military Services and NASA to examine our nation's ability to conduct space-based ISR and communications even during a period of peer state and near peer state attacks intended to deny us our advantages we accrue from our use of space systems. DOD and the ICs past experience is largely one of building small numbers of extraordinarily capable and expensive (exquisite) satellites for communications and ISR. As potential adversaries continue to develop cyber-attack capabilities and have demonstrated an ability to kinetically attack spacecraft, the vulnerability of our architecture is now a serious concern. In addition, the sluggish U.S. economy, the draw down and pull back from a decade of combat operations, and other factors have combined to force a significant reduction in DOD and IC spending over the coming decade(s). Simultaneously, DOD and the IC have a growing awareness that the long lead times and long mission duration of the exquisite space assets can lead to fielding technologies that become obsolete and mission limiting. Some DOD and IC leaders are now examining alternative architectures to provide lower cost, flexible, more diverse and rapidly launchable space systems. Government leaders are considering commercially hosted payloads in geosynchronous orbits and smaller, lower cost, free flying government and commercial satellites in low earth orbits. Additional changes to the ground tasking, processing, exploitation and dissemination (TPED) systems would ensure small satellites have end-to-end mission capability and meet emerging needs such as ease of tasking, multi-INT processing, and more advanced distribution mechanisms (e.g., to users on the move). Today, a majority of agency leaders and their subordinate program managers remain convinced that only large, expensive systems can truly answer requirements and provide reliable

Satellite Media Broadcasting with Adaptive Coding and Modulation

Directory of Open Access Journals (Sweden)

Georgios Gardikis

2009-01-01

Full Text Available Adaptive Coding and Modulation (ACM is a feature incorporated into the DVB-S2 satellite specification, allowing real-time adaptation of transmission parameters according to the link conditions. Although ACM was originally designed for optimizing unicast services, this article discusses the expansion of its usage to broadcasting streams as well. For this purpose, a general cross-layer adaptation approach is proposed, along with its realization into a fully functional experimental network, and test results are presented. Finally, two case studies are analysed, assessing the gain derived by ACM in a real large-scale deployment, involving HD services provision to two different geographical areas.

Evaluation of SLAR and simulated thematic mapper MSS data for forest cover mapping using computer-aided analysis techniques

Science.gov (United States)

Hoffer, R. M.; Dean, M. E.; Knowlton, D. J.; Latty, R. S.

1982-01-01

Kershaw County, South Carolina was selected as the study site for analyzing simulated thematic mapper MSS data and dual-polarized X-band synthetic aperture radar (SAR) data. The impact of the improved spatial and spectral characteristics of the LANDSAT D thematic mapper data on computer aided analysis for forest cover type mapping was examined as well as the value of synthetic aperture radar data for differentiating forest and other cover types. The utility of pattern recognition techniques for analyzing SAR data was assessed. Topics covered include: (1) collection and of TMS and reference data; (2) reformatting, geometric and radiometric rectification, and spatial resolution degradation of TMS data; (3) development of training statistics and test data sets; (4) evaluation of different numbers and combinations of wavelength bands on classification performance; (5) comparison among three classification algorithms; and (6) the effectiveness of the principal component transformation in data analysis. The collection, digitization, reformatting, and geometric adjustment of SAR data are also discussed. Image interpretation results and classification results are presented.

When Enrollments Bulge but Budgets Don't, Consider "Satellite Learning Centers."

Science.gov (United States)

Reecer, Marcia

1988-01-01

Describes Dade County (Florida) schools' answer to crowded classrooms and burgeoning primary enrollments: satellite learning centers built and maintained by local companies as employee childcare benefits. Each center is attached to a nearby "host" school that disburses funds, keeps student records, and supplies support services. (MLH)

Global Broadcast Service Reach Back Via Satellite Tactical Digital Link J (S-TADIL J)

National Research Council Canada - National Science Library

Fenton, Sandra

1999-01-01

...) to deployed forces via UHF Follow On (UFO) satellites during GBS Phase Two. The concept of Smart Push provides for most of the users' needs but cannot anticipate every need or emerging needs of the user...

A Near-Zero Refractive Index Meta-Surface Structure for Antenna Performance Improvement

Directory of Open Access Journals (Sweden)

Mohammad Habib Ullah

2013-11-01

Full Text Available A new meta-surface structure (MSS with a near-zero refractive index (NZRI is proposed to enhance the performance of a square loop antenna array. The main challenge to improve the antenna performance is increment of the overall antenna volume that is mitigated by assimilating the planar NZRI MSS at the back of the antenna structure. The proposed NZRI MSS-loaded CPW-fed (Co-Planar Waveguide four-element array antenna is designed on ceramic-bioplastic-ceramic sandwich substrate using high-frequency structure simulator (HFSS, a finite-element-method-based simulation tool. The gain and directivity of the antenna are significantly enhanced by incorporating the NZRI MSS with a 7 × 6 set of elements at the back of the antenna structure. Measurement results show that the maximum gains of the antenna increased from 6.21 dBi to 8.25 dBi, from 6.52 dBi to 9.05 dBi and from 10.54 dBi to 12.15 dBi in the first, second and third bands, respectively. The effect of the slot configuration in the ground plane on the reflection coefficient of the antenna was analyzed and optimized. The overall performance makes the proposed antenna appropriate for UHFFM (Ultra High Frequency Frequency Modulation telemetry-based space applications as well as mobile satellite, microwave radiometry and radio astronomy applications.

The beginning of a new era - OTC's satellite business services

Science.gov (United States)

Bachmann, Erik

OTC has developed a new range of digital services which will provide business organizations in Australia with high quality private international telecommunications. This range will be known as Satnet and the paper deals with Satnet 2 which is the service offerings using medium-size earth stations (nominally 5- and 7-meter antenna apertures), installed at customers' premises. These services will rely on the Intelsat 6/4 GHz space segment. Operation will be totally digital and will be integrated with no distinction between individual applications such as voice, data, video, etc. Carrier capacities between 64 kb/s and 8.448 Mb/s can be provided and ISDN performance requirements can be supported. The paper describes key service features, systems design and transmission analysis. Consideration is also given to operation, installation and frequency coordination aspects.

Precise Point Positioning with the BeiDou Navigation Satellite System

Directory of Open Access Journals (Sweden)

Min Li

2014-01-01

Full Text Available By the end of 2012, China had launched 16 BeiDou-2 navigation satellites that include six GEOs, five IGSOs and five MEOs. This has provided initial navigation and precise pointing services ability in the Asia-Pacific regions. In order to assess the navigation and positioning performance of the BeiDou-2 system, Wuhan University has built up a network of BeiDou Experimental Tracking Stations (BETS around the World. The Position and Navigation Data Analyst (PANDA software was modified to determine the orbits of BeiDou satellites and provide precise orbit and satellite clock bias products from the BeiDou satellite system for user applications. This article uses the BeiDou/GPS observations of the BeiDou Experimental Tracking Stations to realize the BeiDou and BeiDou/GPS static and kinematic precise point positioning (PPP. The result indicates that the precision of BeiDou static and kinematic PPP reaches centimeter level. The precision of BeiDou/GPS kinematic PPP solutions is improved significantly compared to that of BeiDou-only or GPS-only kinematic PPP solutions. The PPP convergence time also decreases with the use of combined BeiDou/GPS systems.

Precise point positioning with the BeiDou navigation satellite system.

Science.gov (United States)

Li, Min; Qu, Lizhong; Zhao, Qile; Guo, Jing; Su, Xing; Li, Xiaotao

2014-01-08

By the end of 2012, China had launched 16 BeiDou-2 navigation satellites that include six GEOs, five IGSOs and five MEOs. This has provided initial navigation and precise pointing services ability in the Asia-Pacific regions. In order to assess the navigation and positioning performance of the BeiDou-2 system, Wuhan University has built up a network of BeiDou Experimental Tracking Stations (BETS) around the World. The Position and Navigation Data Analyst (PANDA) software was modified to determine the orbits of BeiDou satellites and provide precise orbit and satellite clock bias products from the BeiDou satellite system for user applications. This article uses the BeiDou/GPS observations of the BeiDou Experimental Tracking Stations to realize the BeiDou and BeiDou/GPS static and kinematic precise point positioning (PPP). The result indicates that the precision of BeiDou static and kinematic PPP reaches centimeter level. The precision of BeiDou/GPS kinematic PPP solutions is improved significantly compared to that of BeiDou-only or GPS-only kinematic PPP solutions. The PPP convergence time also decreases with the use of combined BeiDou/GPS systems.

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.

A Space-Based Learning Service for Schools Worldwide

Science.gov (United States)

White, Norman A.; Gibson, Alan

2002-01-01

This paper outlines a scheme for international collaboration to enrich the use of space in school education, to improve students' learning about science and related subjects and to enhance the continuity of science-related studies after the age of 16. Guidelines are presented for the design of an on-line learning service to provide schools worldwide with:- interactive curriculum-related learning resources for teaching about space and through - access to a purpose-designed education satellite or satellites; - opportunities for hands-on work by students in out-of-school hours; - news about space developments to attract, widen and deepen initial interest among teachers - support services to enable teachers to make effective use of the learning service. The Learning Service is the product of almost twenty years of experience by a significant number of UK schools in experimenting with, and in using, satellites and space to aid learning; and over four years of study and development by the SpaceLink Learning Foundation - a private-sector, not- for-profit UK registered charity, which is dedicated to help in increasing both the supply of scientists and engineers and the public understanding of science. This initiative provides scope for, and could benefit from, the involvement of relevant/interested organisations drawn from different countries. The Foundation would be ready, from its UK base, to be among such a group of initiating organisations.

The open prototype for educational NanoSats: Fixing the other side of the small satellite cost equation

Science.gov (United States)

Berk, Josh; Straub, Jeremy; Whalen, David

Government supported nano-satellite launch programs and emerging commercial small satellite launch services are reducing the cost of access to space for educational and other CubeSat projects. The cost and complexity of designing and building these satellites remains a vexing complication for many would be CubeSat aspirants. The Open Prototype for Educational NanoSats (OPEN), a proposed nano-satellite development platform, is described in this paper. OPEN endeavors to reduce the costs and risks associated with educational, government and commercial nano-satellite development. OPEN provides free and publicly available plans for building, testing and operating a versatile, low-cost satellite, based on the standardized CubeSat form-factor. OPEN consists of public-domain educational reference plans, complete with engineering schematics, CAD files, construction and test instructions as well as ancillary reference materials relevant to satellite building and operation. By making the plan, to produce a small but capable spacecraft freely available, OPEN seeks to lower the barriers to access on the other side (non-launch costs) of the satellite cost equation.

Open Source GIS Connectors to NASA GES DISC Satellite Data

Science.gov (United States)

Kempler, Steve; Pham, Long; Yang, Wenli

2014-01-01

The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) houses a suite of high spatiotemporal resolution GIS data including satellite-derived and modeled precipitation, air quality, and land surface parameter data. The data are valuable to various GIS research and applications at regional, continental, and global scales. On the other hand, many GIS users, especially those from the ArcGIS community, have difficulties in obtaining, importing, and using our data due to factors such as the variety of data products, the complexity of satellite remote sensing data, and the data encoding formats. We introduce a simple open source ArcGIS data connector that significantly simplifies the access and use of GES DISC data in ArcGIS.

Network flexibility of the IRIDIUM (R) Global Mobile Satellite System

Science.gov (United States)

Hutcheson, Jonathan; Laurin, Mala

1995-01-01

The IRIDIUM system is a global personal communications system supported by a constellation of 66 low earth orbit (LEO) satellites and a collection of earth-based 'gateway' switching installations. Like traditional wireless cellular systems, coverage is achieved by a grid of cells in which bandwidth is reused for spectral efficiency. Unlike any cellular system ever built, the moving cells can be shared by multiple switching facilities. Noteworthy features of the IRIDIUM system include inter-satellite links, a GSM-based telephony architecture, and a geographically controlled system access process. These features, working in concert, permit flexible and reliable administration of the worldwide service area by gateway operators. This paper will explore this unique concept.

Programming a real-time operating system for satellite control applications Satellite Control Applications

International Nuclear Information System (INIS)

Omer, M.; Anjum, O.; Suddle, M.R.

2004-01-01

With the realization of ideas like formation flights and multi-body space vehicles the demands on an attitude control system have become increasingly complex. Even in its most simplified form, the control system for a typical geostationary satellite has to run various supervisory functions along with determination and control algorithms side by side. Within each algorithm it has to employ multiple actuation and sensing mechanisms and service real time interrupts, for example, in the case of actuator saturation and sensor data fusion. This entails the idea of thread scheduling and program synchronization, tasks specifically meant for a real time OS. This paper explores the embedding of attitude determination and control loop within the framework of a real time operating system provided for TI's DSP C6xxx series. The paper details out the much functionality provided within the scaleable real time kernel and the analysis and configuration tools available, It goes on to describe a layered implementation stack associated with a typical control for Geo Stationary satellites. An application for control is then presented in which state of the art analysis tools are employed to view program threads, synchronization semaphores, hardware interrupts and data exchange pipes operating in real time. (author)

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

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.

Engineering Documentation and Data Control

Science.gov (United States)

Matteson, Michael J.; Bramley, Craig; Ciaruffoli, Veronica

2001-01-01

Mississippi Space Services (MSS) the facility services contractor for NASA's John C. Stennis Space Center (SSC), is utilizing technology to improve engineering documentation and data control. Two identified improvement areas, labor intensive documentation research and outdated drafting standards, were targeted as top priority. MSS selected AutoManager(R) WorkFlow from Cyco software to manage engineering documentation. The software is currently installed on over 150 desctops. The outdated SSC drafting standard was written for pre-CADD drafting methods, in other words, board drafting. Implementation of COTS software solutions to manage engineering documentation and update the drafting standard resulted in significant increases in productivity by reducing the time spent searching for documents.

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....

NASA/DARPA advanced communications technology satellite project for evaluation of telemedicine outreach using next-generation communications satellite technology: Mayo Foundation participation.

Science.gov (United States)

Gilbert, B K; Mitchell, M P; Bengali, A R; Khandheria, B K

1999-08-01

To describe the development of telemedicine capabilities-application of remote consultation and diagnostic techniques-and to evaluate the feasibility and practicality of such clinical outreach to rural and underserved communities with limited telecommunications infrastructures. In 1992, Mayo Foundation (Rochester, Minn, Jacksonville, Fla, and Scottsdale, Ariz), the National Aeronautics and Space Administration, and the Defense Advanced Research Projects Agency collaborated to create a complex network of fiberoptic landlines, video recording systems, satellite terminals, and specially developed data translators linking Mayo sites with other locations in the continental United States on an on-demand basis. The purpose was to transmit data via the asynchronous transfer mode (ATM) digital communications protocol over the Advanced Communications Technology Satellite. The links were intended to provide a conduit for transmission of data for patient-specific consultations between physicians, evaluation of medical imagery, and medical education for clinical staffs at remote sites. Low-data-rate (LDR) experiments went live late in 1993. Mayo Clinic Rochester successfully provided medical consultation and services to 2 small regional medical facilities. High-data-rate (HDR) experiments included studies of remote digital echocardiography, store-and-forward telemedicine, cardiac catheterization, and teleconsultation for congenital heart disease. These studies combined landline data transmission with use of the satellite. The complexity of the routing paths and network components, immaturity of available software, and inexperience with existing telecommunications caused significant study delays. These experiments demonstrated that next-generation satellite technology can provide batch and real-time imagery for telemedicine. The first-generation of the ATM and satellite network technology used in these experiments created several technical problems and inconveniences that should

Payload system tradeoffs for mobile communications satellites

Science.gov (United States)

Moody, H. J.

1990-01-01

System level trade-offs carried out during Mobile Satellite (M-SAT) design activities are described. These trade-offs relate to the use of low level beam forming, flexible power and spectrum distribution, and selection of the number of beams to cover the service area. It is shown that antenna performance can be improved by sharing horns between beams using a low level beam forming network (BFN). Additionally, greatly increased power utilization is possible using a hybrid matrix concept to share power between beams.

Potential Market for Satellite Technology in Meeting Telecommunication Needs of Developing Nations

Science.gov (United States)

1996-01-01

A recent study examined the potential for satellite technology to meet the telecommunication needs of developing nations. The growth of these nations depends on their attracting and holding the industrial investments of developed nations. This will not be likely with the antiquated telecommunications infrastructure typical of developing nations. On the contrary, it will require an infrastructure that is compatible with international standards. Most of the developing nations perceive this necessity and are pursuing the necessary upgrades. The rate of replacement, types of technology, services affected, and the terrestrial/satellite mix differ by each nation's priorities and gross national product (GNP).

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.

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.