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1

Communications satellites in non-geostationary orbits  

NASA Technical Reports Server (NTRS)

The design of a satellite communications system in an orbit lower than GEO is described. Two sun-synchronous orbits which lie in the equatorial plane have been selected: (1) the apogee at constant time-of-day equatorial orbit, a highly eccentric orbit with five revolutions per day, which allows 77-135 percent more satellite mass to be placed in orbit than for GEO; and (2) the sun-synchronous 12-hour equatorial orbit, a circular orbit with two revolutions per day, which allows 23-29 percent more mass. The results of a life cycle economic analysis illustrate that nongeostationary satellite systems could be competitive with geostationary satellite systems.

Price, Kent M.; Doong, Wen; Nguyen, Tuan Q.; Turner, Andrew E.; Weyandt, Charles

1988-01-01

2

Servicing communication satellites in geostationary orbit  

NASA Technical Reports Server (NTRS)

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.

Russell, Paul K.; Price, Kent M.

1990-01-01

3

Optimal strategies for orbital inclination control of geostationary satellite  

NASA Astrophysics Data System (ADS)

Using the inclination vector as a nonsingular orbital element, engineering-oriented mathematical models for inclination control of geostationary orbits are established, and unified optimal strategies for inclination control both in north-south station aquisition and north-south stationkeeping are derived. The results are applicable to missions which require north-south stationkeeping accuracy of about 0.05-0.1 deg and were implemented in flight control of the Chinese STW-2 satellite.

Li, Tieshou

1990-02-01

4

Geostationary Earth Orbit Satellite Model using Easy Java Simulation  

E-print Network

We develop an Easy Java Simulation (EJS) model for students to visualize geostationary orbits near Earth, modeled using Java 3D implementation of the EJS 3D library. The simplified physics model is described and simulated using simple constant angular velocity equation. Four computer model design ideas such as 1) simple and realistic 3D view and associated learning to real world, 2) comparative visualization of permanent geostationary satellite 3) examples of non-geostationary orbits of different 3-1) rotation sense, 3-2) periods, 3-3) planes and 4) incorrect physics model for conceptual discourse are discussed. General feedback from the students has been relatively positive, and we hope teachers will find the computer model useful in their own classes.

Wee, Loo Kang; 10.1088/0031-9120/48/1/72

2012-01-01

5

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

Microsoft Academic Search

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

N. Brady

2002-01-01

6

The use of satellites in non-geostationary orbits for unloading geostationary communication satellite traffic peaks. Volume 1: Executive summary  

NASA Technical Reports Server (NTRS)

The overall objective of this program was to assess the application, economic benefits, and technology and system implications of satellites in non-geostationary (non-GEO) orbits for off-loading peak traffic from GEO communications satellites. The study was organized into four technical tasks which are described in turn. They are: (1) concepts development; (2) system definition; (3) economic comparisons; and (4) technology requirements definition. Each of these tasks is defined in detail and the results of each are given.

Price, K.; Turner, A.; Nguyen, T.; Doong, W.; Weyandt, C.

1987-01-01

7

78 FR 14920 - Earth Stations Aboard Aircraft Communicating With Fixed-Satellite Service Geostationary-Orbit...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Fixed-Satellite Service Geostationary-Orbit Space Stations AGENCY: Federal Communications...Service (FSS) geostationary-orbit (GSO) space stations operating in the 10.95-11...45-11.7 GHz, 11.7-12.2 GHz (space-to-Earth or downlink) and...

2013-03-08

8

The use of satellites in non-goestationary orbits for unloading geostationary communication satellite traffic peaks. Volume 2: Technical report  

NASA Technical Reports Server (NTRS)

The part of the geostationary (GEO) orbital arc used for United States domestic fixed, communications service is rapidly becoming filled with satellites. One of the factors currently limiting its utilization is that communications satellites must be designed to have sufficient capacity to handle peak traffic leads, and thus are under utilized most of the time. A solution is to use satellites in suitable non-geostationary orbits to unload the traffic peaks. Three different designs for a non-geostationary orbit communications satellite system are presented for the 1995 time frame. The economic performance is analyzed and compared with geostationary satellites for two classes of service, trunking and customer premise service. The result is that the larger payload of the non-geostationary satellite offsets the burdens of increased complexity and worse radiation environment to give improved economic performance. Depending on ground terminal configuration, the improved economic performance of the space segment may be offset by increased ground terminal expenses.

Price, K.; Turner, A.; Nguyen, T.; Doong, W.; Weyandt, C.

1987-01-01

9

A Geostationary Earth Orbit Satellite Model Using Easy Java Simulation  

ERIC Educational Resources Information Center

We develop an Easy Java Simulation (EJS) model for students to visualize geostationary orbits near Earth, modelled using a Java 3D implementation of the EJS 3D library. The simplified physics model is described and simulated using a simple constant angular velocity equation. We discuss four computer model design ideas: (1) a simple and realistic…

Wee, Loo Kang; Goh, Giam Hwee

2013-01-01

10

Astrometric reduction of geostationary satellites optical observations for orbit determination (PASAGE)  

NASA Astrophysics Data System (ADS)

The precise knowledge of the ephemerides of the geostationary satellites is a key point in mission control for the satellite control agencies both for planning manoeuvres and for checking their results. The major goal of the PASAGE project (Astrometric Positioning of Geostationary Satellites) is to use earth-based astrometric observations for obtaining precise ephemerides and the subsequent orbit determination. In order to carry out this special ground-based astrometric application, we have developed special algorithms and techniques that make it possible for us to achieve accuracies of a few tenths of an arc second in the geostationary satellite apparent topocentric positions, even from places with high light pollution.

Montojo, F. J.; López Moratalla, T.; Abad, C.; Muiños, J. L.

2008-12-01

11

Time Resolved Atmospheric Carbon Satellite Observations from Geostationary Orbit  

NASA Astrophysics Data System (ADS)

This presentation describes proposed satellite carbon measurements from CHRONOS (Commercially Hosted spectroRadiometer Observations and New Opportunities for Science). The primary goal of this mission is to measure the atmospheric pollutants carbon monoxide (CO) and methane (CH4) from geostationary orbit, with hourly observations of North America at high spatial resolution. Carbon monoxide is produced by combustion processes such as urban activity and wildfires, and serves as a proxy for other combustion pollutants that are not easily measured. Both CO and CH4 are chemical precursors of tropospheric ozone pollution. Methane has diverse anthropogenic sources ranging from fossil fuel production, animal husbandry, agriculture and waste management. The impact of gas exploration in the Western States of the USA and oil extraction from the Canadian tar sands will be particular foci of the mission, as will the poorly-quantified natural CH4 emissions from wetlands and thawing permafrost. In addition to characterizing pollutant sources, improved understanding of the domestic CH4 budget is a priority for policy decisions related to short-lived climate forcers. A primary motivation for targeting CO is its value as a tracer of atmospheric pollution. The CHRONOS measurements will provide insight into local and long-range transport across the North American continent, as well as the processes governing the entrainment and venting of pollution in and out of the planetary boundary layer. As a result of significantly improved characterization of diurnal changes in atmospheric composition, CHRONOS observations will find direct societal applications for air quality regulation and forecasting. We present a quantification of this expected improvement in the prediction of near-surface concentrations when CHRONOS measurements are used in Observation System Simulation Experiments (OSSEs). If CHRONOS and the planned NASA Earth Venture TEMPO (Tropospheric Emissions: Monitoring of Pollution) mission were implemented concurrently, the resulting measurement suite would efficiently and expeditiously serve to address the science goals of the Decadal Survey proposed GEO-CAPE mission.

Edwards, D. P.; Worden, H. M.; Deeter, M. N.; Worden, H. M.

2013-12-01

12

Time Resolved Atmospheric Carbon Satellite Observations from Geostationary Orbit  

NASA Astrophysics Data System (ADS)

This presentation describes proposed satellite carbon measurements from CHRONOS (Commercially Hosted spectroRadiometer Observations and New Opportunities for Science). The primary goal of this mission is to measure the atmospheric pollutants carbon monoxide (CO) and methane (CH4) from geostationary orbit, with hourly observations of North America at high spatial resolution. Carbon monoxide is produced by combustion processes such as urban activity and wildfires, and serves as a proxy for other combustion pollutants that are not easily measured. Both CO and CH4 are chemical precursors of tropospheric ozone pollution. Methane has diverse anthropogenic sources ranging from fossil fuel production, animal husbandry, agriculture and waste management. The impact of gas exploration in the Western States of the USA and oil extraction from the Canadian tar sands will be particular foci of the mission, as will the poorly-quantified natural CH4 emissions from wetlands and thawing permafrost. In addition to characterizing pollutant sources, improved understanding of the domestic CH4 budget is a priority for policy decisions related to short-lived climate forcers. A primary motivation for targeting CO is its value as a tracer of atmospheric pollution. The CHRONOS measurements will provide insight into local and long-range transport across the North American continent, as well as the processes governing the entrainment and venting of pollution in and out of the planetary boundary layer. As a result of significantly improved characterization of diurnal changes in atmospheric composition, CHRONOS observations will find direct societal applications for air quality regulation and forecasting. We present a quantification of this expected improvement in the prediction of near-surface concentrations when CHRONOS measurements are used in Observation System Simulation Experiments (OSSEs). If CHRONOS and the planned NASA Earth Venture TEMPO (Tropospheric Emissions: Monitoring of Pollution) mission were implemented concurrently, the resulting measurement suite would efficiently and expeditiously serve to address the science goals of the Decadal Survey proposed GEO-CAPE mission.

Edwards, David; Worden, Helen

13

New non-geosynchronous orbits for communications satellites to off-load daily peaks in geostationary traffic  

NASA Technical Reports Server (NTRS)

The potential for satellites in two orbits, the sun-synchronous 12-hour equatorial orbit (STET) and the apogee at constant time-of-day equatorial orbit (ACE), to off-load peaks in the CONUS geostationary communications traffic is discussed. These orbits are found to require maneuvers of smaller magnitudes for insertion than geostationary orbits. Advantages of the ACE orbit over the STET orbit are discussed, including larger satellite mass capability for a given launch vehicle, lower slant ranges, and larger angular separation from the geostationary arc for a nonequatorial ground observer.

Turner, A. E.

1987-01-01

14

78 FR 14952 - Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Fixed-Satellite Service Geostationary-Orbit Space Stations AGENCY: Federal Communications...be authorized to communicate with GSO space stations of the FSS on a primary basis in the 11.7-12.2 GHz band (space-to-Earth), on an unprotected...

2013-03-08

15

Coarse Initial Orbit Determination for a Geostationary Satellite Using Single-Epoch GPS Measurements.  

PubMed

A practical algorithm is proposed for determining the orbit of a geostationary orbit (GEO) satellite using single-epoch measurements from a Global Positioning System (GPS) receiver under the sparse visibility of the GPS satellites. The algorithm uses three components of a state vector to determine the satellite's state, even when it is impossible to apply the classical single-point solutions (SPS). Through consideration of the characteristics of the GEO orbital elements and GPS measurements, the components of the state vector are reduced to three. However, the algorithm remains sufficiently accurate for a GEO satellite. The developed algorithm was tested on simulated measurements from two or three GPS satellites, and the calculated maximum position error was found to be less than approximately 40 km or even several kilometers within the geometric range, even when the classical SPS solution was unattainable. In addition, extended Kalman filter (EKF) tests of a GEO satellite with the estimated initial state were performed to validate the algorithm. In the EKF, a reliable dynamic model was adapted to reduce the probability of divergence that can be caused by large errors in the initial state. PMID:25835299

Kim, Ghangho; Kim, Chongwon; Kee, Changdon

2015-01-01

16

Attitude controller design for orbital target tracking of geostationary satellite under avoidance constraint  

NASA Astrophysics Data System (ADS)

A coordinated attitude control problem is addressed for which a geostationary satellite should maintain communication with a ground station while simultaneously tracking space objects. The coordinated attitude control discussed in this study is related to the attitude maneuvers of a tracking satellite and to the orbital motion of targets placed in orbits of lower altitudes. Modified Rodrigues parameters are employed to avoid singularities even in the presence of large attitude maneuvers. The initial attitude error is calculated based upon an arbitrary initial configuration for the target tracking, so that a sequential tracking from one to another target can be achieved easily. Additionally, avoidance maneuvers aimed at protecting sensitive onboard sensors from the Sun and the Moon are designed using the so-called navigation function. When the avoidance areas are on the transient path due to the coordinated attitude maneuver command, the maneuver is performed with no violation against the given constraint areas by adopting the navigation function.

Park, Young-Woong; Bang, Hyochoong

2011-04-01

17

Land Surface Temperature- Comparing Data from Polar Orbiting and Geostationary Satellites  

NASA Astrophysics Data System (ADS)

Land Surface Temperature (LST) is a vital parameter in Earth climate science, driving long-wave radiation exchanges that control the surface energy budget and carbon fluxes, which are important factors in Numerical Weather Prediction (NWP) and the monitoring of climate change. Satellites offer a convenient way to observe LST consistently and regularly over large areas. A comparison between LST retrieved from a Geostationary Instrument, the Spinning Enhanced Visible and InfraRed Imager (SEVIRI), and a Polar Orbiting Instrument, the Advanced Along Track Scanning Radiometer (AATSR) is presented. Both sensors offer differing benefits. AATSR offers superior precision and spatial resolution with global coverage but given its sun-synchronous platform only observes at two local times, ~10am and ~10pm. SEVIRI provides the high-temporal resolution (every 15 minutes) required for observing diurnal variability of surface temperatures but given its geostationary platform has a poorer resolution, 3km at nadir, which declines at higher latitudes. A number of retrieval methods are applied to the raw satellite data: First order coefficient based algorithms provided on an operational basis by the LandSAF (for SEVIRI) and the University of Leicester (for AATSR); Second order coefficient based algorithms put forward by the University of Valencia; and an optimal estimation method using the 1DVar software provided by the NWP SAF. Optimal estimation is an iterative technique based upon inverse theory, thus is very useful for expanding into data assimilation systems. The retrievals are assessed and compared on both a fine scale using in-situ data from recognised validation sites and on a broad scale using two 100x100 regions such that biases can be better understood. Overall, the importance of LST lies in monitoring daily temperature extremes, e.g. for estimating permafrost thawing depth or risk of crop damage due to frost, hence the ideal dataset would use a combination of observations. Results show that there is a strong agreement for night-time matchups and understandable biases for the daytime matchups, owing to the differing viewing geometry and relative sun position. This comparison gives promise to the possibility of constructing a combined retrieval mechanism which draws the best characteristics from each instrument with possible courses of action identified.

Comyn-Platt, E.; Remedios, J. J.; Good, E. J.; Ghent, D.; Saunders, R.

2012-04-01

18

Land and Ocean Surface Skin Temperature from Geostationary and Low Earth Orbit Satellite Observations  

NASA Astrophysics Data System (ADS)

Observations from imagers aboard Geostationary Earth Orbit (GEO) and Low Earth Orbit (LEO) satellites allow for spatially detailed, near-real-time retrievals of cloud and surface radiation properties. Validating and improving the quality of these observations is important for the advancement of climate studies. Compared to GEO sensors, LEO-based instruments can typically provide higher-spatial-resolution datasets, but at the cost of limited areal coverage and reduced sampling frequency at any given location. Conversely, the persistence and coverage of GEO-based imagers offer the opportunity for more frequent retrievals of near-instantaneous, near-global surface properties. Among other cloud and clear-sky retrieval parameters, NASA Langley provides pixel-level land and ocean skin temperature datasets by comparing clear-pixel top-of-atmosphere infrared temperature observations with modeled, atmospheric-absorption-corrected surface temperature values. Depending on cloud-cover thresholds, this method yields surface temperature values that are within 0.5 to 2.0 K of measurements from ground-based networks including the Southern Great Plains Atmospheric Radiation Measurement Climate Research Facility, the U.S. Climate Reference Network, and the global Baseline Surface Radiation Network. Furthermore, monthly mean sea surface temperatures (SSTs) are within 0.5 to 2.0 K of NOAA-based SST climatology records, and have an uncertainty of less than 1 K. These data will be useful for assimilation into atmospheric models, which offer improved performance when high-accuracy, high-resolution initial radiometric and surface conditions are included. Modelers should find the immediate availability and broad coverage of these skin temperature observations valuable, which can lead to improved forecasting and more advanced global climate models.

Scarino, B. R.; Minnis, P.; Palikonda, R.; Heck, P.; Bedka, K.

2013-12-01

19

Geostationary Satellite Data  

NSDL National Science Digital Library

This site, hosted by the Global Hydrology and Climate Center, a US National Aeronautics and Space Administration research center, provides real time images of the earth. Images are available for five regions: North America (1km); North and South America, Atlantic, and East Pacific (32km); Hawaii, Pacific Ocean and North America (32km); Japan, Australia, West Pacific, and Asia (32km); and a global geostationary satellite composite (56km). Users have the option of zooming in on a selected region of the image. Java based image animations are also available. Data for the images are obtained from three different satellites, GOES-8, GOES-9, and GMS-5. Images are updated every 30 minutes.

20

Astrometric Positioning of Geostationary Satellites (PASAGE)  

NASA Astrophysics Data System (ADS)

The PASAGE project major goal is to use earth-based astrometric observations to calculate precise ephemeris of geostationary satellites and for orbital determination of these satellites. This special use of astrometry is quite different from classical one and has required the development of the necessary techniques and algorithms for processing the observations.

López Moratalla, T.; Montojo, F. J.; Abad, C.; Pizarro, J.; Muiños, J. L.; Galindo, P.; Palacio, J.

2009-05-01

21

OAA's geostationary and polar-orbiting satellites provide critical data for short-term and  

E-print Network

-- on constant vigil for severe weather conditions such as tornadoes, flash floods, hail storms, and hurricanes imagery also is used to estimate rainfall during the thunderstorms and hurricanes for flash flood warnings the latest rescue figures at http://www.sarsat.noaa.gov/). We currently have two satellites in orbit (a

22

Monitoring volcanic ash cloud top height through simultaneous retrieval of optical data from polar orbiting and geostationary satellites  

NASA Astrophysics Data System (ADS)

Volcanic ash cloud-top height (ACTH) can be monitored on the global level using satellite remote sensing. Here we propose a photogrammetric method based on the parallax between data retrieved from geostationary and polar orbiting satellites to overcome some limitations of the existing methods of ACTH retrieval. SEVIRI HRV band and MODIS band 1 are a good choice because of their high resolution. The procedure works well if the data from both satellites are retrieved nearly simultaneously. MODIS does not retrieve the data at exactly the same time as SEVIRI. To compensate for advection we use two sequential SEVIRI images (one before and one after the MODIS retrieval) and interpolate the cloud position from SEVIRI data to the time of MODIS retrieval. The proposed method was tested for the case of the Eyjafjallajökull eruption in April 2010. The parallax between MODIS and SEVIRI data can reach 30 km, which implies an ACTH of approximately 12 km at the beginning of the eruption. At the end of April eruption an ACTH of 3-4 km is observed. The accuracy of ACTH was estimated to be 0.6 km.

Zakšek, K.; Hort, M.; Zaletelj, J.; Langmann, B.

2013-03-01

23

Monitoring volcanic ash cloud top height through simultaneous retrieval of optical data from polar orbiting and geostationary satellites  

NASA Astrophysics Data System (ADS)

Volcanic ash cloud top height (ACTH) can be monitored on the global level using satellite remote sensing. Here we propose a photogrammetric method based on the parallax between data retrieved from geostationary and polar orbiting satellites to overcome some limitations of the existing methods of ACTH retrieval. SEVIRI HRV band and MODIS band 1 are a good choice because of their high resolution. The procedure works well if the data from both satellites are retrieved nearly simultaneously. MODIS does not retrieve the data at exactly the same time as SEVIRI. To compensate for advection we use two sequential SEVIRI images (one before and one after the MODIS retrieval) and interpolate the cloud position from SEVIRI data to the time of MODIS retrieval. The proposed method was tested for the case of the Eyjafjallajökull eruption in April 2010. The parallax between MODIS and SEVIRI data can reach over 30 km which implies ACTH of more than 12 km in the beginning of the eruption. In the end of April eruption ACTH of 3-4 km is observed. The accuracy of ACTH was estimated to be 0.6 km.

Zakšek, K.; Hort, M.; Zaletelj, J.; Langmann, B.

2012-09-01

24

Transmitter diversity verification on ARTEMIS geostationary satellite  

NASA Astrophysics Data System (ADS)

Optical feeder links will become the extension of the terrestrial fiber communications towards space, increasing data throughput in satellite communications by overcoming the spectrum limitations of classical RF-links. The geostationary telecommunication satellite Alphasat and the satellites forming the EDRS-system will become the next generation for high-speed data-relay services. The ESA satellite ARTEMIS, precursor for geostationary orbit (GEO) optical terminals, is still a privileged experiment platform to characterize the turbulent channel and investigate the challenges of free-space optical communication to GEO. In this framework, two measurement campaigns were conducted with the scope of verifying the benefits of transmitter diversity in the uplink. To evaluate this mitigation technique, intensity measurements were carried out at both ends of the link. The scintillation parameter is calculated and compared to theory and, additionally, the Fried Parameter is estimated by using a focus camera to monitor the turbulence strength.

Mata Calvo, Ramon; Becker, Peter; Giggenbach, Dirk; Moll, Florian; Schwarzer, Malte; Hinz, Martin; Sodnik, Zoran

2014-03-01

25

Geostationary satellites and space debris around the Earth (on Russian)  

NASA Astrophysics Data System (ADS)

Classification of artificial satellites, the history of development of the geostationary orbit (GSO). The main aim of ground-based optical, radar and other observations GSS. Methods of observation and control of the GSO. Catalogues satellites leading space country. The problem of space debris and the Kessler syndrome. Flashes from the satellites of the constellation "Iridium", and flashes from geostationary satellites. Tips, advice for amateur astronomers to observe when the flash GSS.

Sukhov, P., P.

26

Geostationary Satellite Server  

NSDL National Science Digital Library

This database contains imagery from geosationary satellites. Visitors can access daily images or archived imagery form GOES-9, METEOSAT, and other satellites. The imagery features hemispheric and whole-disk views of Earth, water vapor maps, and images of storms and other special events. Links to satellite homepages and to other related topics are included.

27

Impact of Non-geostationary Orbits on PASS  

NASA Technical Reports Server (NTRS)

The use of satellites in non-geostationary orbits (NGO) for PASS (Personal Access Satellite System) is discussed. The following subject areas are covered: (1) orbit parameters (circular and elliptical orbit characteristics); (2) link characteristics (Doppler shift, propagation loss, CONUS coverage antenna, multibeam antenna gain, and impact on link equations); (3) number of satellites required for continuous CONUS coverage (circular and elliptical orbit results); and (4) advantages and disadvantages of NGOs.

Estabrook, Polly; Motamedi, Masoud

1990-01-01

28

Geostationary satellite observations of ozone air quality  

NASA Astrophysics Data System (ADS)

Ozone in surface air is the primary cause of polluted air in the United States. The current ozone observing network is insufficient either to assess air quality or to fully inform our understanding of the factors controlling tropospheric ozone. This thesis investigates the benefit of an instrument in geostationary orbit for observing near surface ozone using Observing System Simulation Experiments (OSSEs). An OSSE was performed to define the measurement requirements for geostationary observations of ozone air quality. Hourly observations of ozone from geostationary orbit improve the assimilation considerably relative to daily observation from low earth orbit. There is little propagation of ozone information from the free troposphere to the surface, making instrument sensitivity in the boundary layer is essential. Assimilation of data from a best-case multispectral instrument reduces model error for surface ozone by a factor of two. A joint assimilation framework was developed to use observations of carbon monoxide as an additional constraint on surface ozone concentrations through exploitation of model error correlations. Ozone-CO error correlations are positive in continental outflow but negative over land on a regional scale. Joint ozone-CO data assimilation provides substantial benefit for informing US ozone air quality if the instrument sensitivity for CO in the boundary layer is greater than that for ozone. Planned geostationary TEMPO satellite observations of ozone were used in conjunction with complementary surface and low-elevation orbit observations to demonstrate the capability of a future observing system to monitor and attribute air quality exceedances in the Intermountain West. Assimilation of surface measurements alone does not capture elevated ozone levels. Assimilation of TEMPO geostationary observations greatly improves the assimilated model's ability to reproduce ozone exceedances and attribute them to background influence.

Zoogman, Peter William

29

The geostationary orbit and developing countries  

NASA Technical Reports Server (NTRS)

The geostationary orbit is becoming congested due to use by several countries throughout the world, and the request for use of this orbit is increasing. There are 188 geostationary stations in operation. An equitable distribution of stations on this orbit is requested.

Medina, E. R.

1982-01-01

30

47 CFR 101.145 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2014 CFR

...false Interference to geostationary-satellites. 101.145 Section 101.145 ...145 Interference to geostationary-satellites. These limitations are necessary...geostationary-space stations in the fixed-satellite service. (a) Stations...

2014-10-01

31

47 CFR 78.106 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2011 CFR

...Interference to geostationary-satellites. 78.106 Section 78...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. Applicants and licensees...interference to geostationary-satellites. [68 FR 12776,...

2011-10-01

32

47 CFR 74.643 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2013 CFR

...Interference to geostationary-satellites. 74.643 Section 74...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. Applicants and licensees...interference to geostationary-satellites. [68 FR 12771,...

2013-10-01

33

47 CFR 101.145 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2012 CFR

...Interference to geostationary-satellites. 101.145 Section 101...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. Link to an amendment...geostationary-space stations in the fixed-satellite service. (a)...

2012-10-01

34

47 CFR 101.145 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2013 CFR

...Interference to geostationary-satellites. 101.145 Section 101...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. These limitations...geostationary-space stations in the fixed-satellite service. (a)...

2013-10-01

35

47 CFR 78.106 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2013 CFR

...Interference to geostationary-satellites. 78.106 Section 78...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. Applicants and licensees...interference to geostationary-satellites. [68 FR 12776,...

2013-10-01

36

47 CFR 78.106 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2010 CFR

...Interference to geostationary-satellites. 78.106 Section 78...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. Applicants and licensees...interference to geostationary-satellites. [68 FR 12776,...

2010-10-01

37

47 CFR 101.145 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2010 CFR

...Interference to geostationary-satellites. 101.145 Section 101...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. These limitations...geostationary-space stations in the fixed-satellite service. (a)...

2010-10-01

38

47 CFR 101.145 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2011 CFR

...Interference to geostationary-satellites. 101.145 Section 101...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. These limitations...geostationary-space stations in the fixed-satellite service. (a)...

2011-10-01

39

47 CFR 78.106 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2012 CFR

...Interference to geostationary-satellites. 78.106 Section 78...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. Applicants and licensees...interference to geostationary-satellites. [68 FR 12776,...

2012-10-01

40

47 CFR 74.643 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2011 CFR

...Interference to geostationary-satellites. 74.643 Section 74...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. Applicants and licensees...interference to geostationary-satellites. [68 FR 12771,...

2011-10-01

41

47 CFR 74.643 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2012 CFR

...Interference to geostationary-satellites. 74.643 Section 74...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. Applicants and licensees...interference to geostationary-satellites. [68 FR 12771,...

2012-10-01

42

47 CFR 78.106 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2014 CFR

...Interference to geostationary-satellites. 78.106 Section 78...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. Applicants and licensees...interference to geostationary-satellites. [68 FR 12776,...

2014-10-01

43

47 CFR 74.643 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2010 CFR

...Interference to geostationary-satellites. 74.643 Section 74...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. Applicants and licensees...interference to geostationary-satellites. [68 FR 12771,...

2010-10-01

44

47 CFR 74.643 - Interference to geostationary-satellites.  

Code of Federal Regulations, 2014 CFR

...Interference to geostationary-satellites. 74.643 Section 74...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...Interference to geostationary-satellites. Applicants and licensees...interference to geostationary-satellites. [68 FR 12771,...

2014-10-01

45

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

Federal Register 2010, 2011, 2012, 2013, 2014

...CFR Parts 2 and 25 [IB Docket No. 12-376; FCC 12-161] Earth Stations Aboard Aircraft Communicating with Fixed-Satellite...Register of March 8, 2013. The document proposed rules for Earth Stations Aboard Aircraft. FOR FURTHER INFORMATION...

2013-03-29

46

The geostationary Earth radiation budget (GERB) instrument on EUMETSAT's MSG satellite  

Microsoft Academic Search

Geostationary Earth radiation budget (GERB) is an Announcement of Opportunity Instrument for EUMETSAT's Meteosat Second Generation (MSG) satellite. GERB will make accurate measurements of the Earth Radiation Budget from geostationary orbit, provide an absolute reference calibration for LEO Earth radiation budget instruments and allow studies of the energetics of atmospheric processes. By operating from geostationary orbit, measurements may be made

M. C. W. Sandford; P. M. Allan; M. E. Caldwell; J. Delderfield; M. B. Oliver; E. Sawyer; J. E. Harries; J. Ashmall; H. Brindley; S. Kellock; R. Mossavati; R. Wrigley; D. Llewellyn-Jones; O. Blake; G. Butcher; R. Cole; N. Nelms; S. DeWitte; P. Gloesener; F. Fabbrizzi

2003-01-01

47

High vs Low Thrust Station Keeping Maneuver Planning for Geostationary Satellites  

E-print Network

theory Key words Chemical and electrical propulsion systems Geostationary satellite station keeping Orbit control Control saturation constraints Trajectory optimization via direct methods Fixed horizon optimal

Paris-Sud XI, Université de

48

Geostationary Lightning Imager for FY-4 Meteorological Satellite (Invited)  

NASA Astrophysics Data System (ADS)

The FY-4 satellite scheduled to launch in 2015 is a second-generation Chinese geostationary meteorological satellite. The main payloads for FY-4 satellite include Geostationary Lightning Imager (GLI), Advanced Geostationary Visible and Infrared Imager (AGVII), and Geostationary Interfering Infrared Sounder (GIIRS). Since the GLI is the first lightning detection imager without any heritage on a Chinese meteorological satellite, it is a great challenge to implement this mission. The GLI covers the most part of China, land and ocean and nearby areas. The continuous and real time lightning imaging products from GLI will be applied to weather forecasting, convection event monitoring, and typhoon tracking. The instrument formulation studies started 4 years ago, and now it is at implementation stage of making prototype models. A working group has begun to develop the L1 and L2 algorithms for lightning imaging data processing. At present, we are focusing on resolving several critical issues for GLI. The first one is how to make sure the Real Time Event Processor (RTEP) works well in orbit, which relates whether or not the lightning information could be picked up correctly. The second is how to make best uses of lightning imaging products from GLI in all kinds of application fields. Since the Geostationary Lightning Mapper (GLM) and Lighting Imager (LI) are lighting imagers on geostationary satellites with similar instrument structure and working principles to GLI, we welcome international collaboration on GLI lightning products: algorithm development, lightning imaging applications, and other relative topics.

Huang, F.

2010-12-01

49

Geostationary satellite observations of dynamic phytoplankton photophysiology  

NASA Astrophysics Data System (ADS)

Since June 2010, the Geostationary Ocean Color Imager (GOCI) has been collecting the first diurnally resolved satellite ocean measurements. Here GOCI retrievals of phytoplankton chlorophyll concentration and fluorescence are used to evaluate daily to seasonal changes in photophysiological properties. We focus on nonphotochemical quenching (NPQ) processes that protect phytoplankton from high light damage and cause strong diurnal cycles in fluorescence emission. This NPQ signal varies seasonally, with maxima in winter and minima in summer. Contrary to expectations from laboratory studies under constant light conditions, this pattern is highly consistent with an earlier conceptual model and recent field observations. The same seasonal cycle is registered in fluorescence data from the polar-orbiting Moderate Resolution Imaging Spectroradiometer Aqua satellite sensor. GOCI data reveal a strong correlation between mixed layer growth irradiance and fluorescence-derived phytoplankton photoacclimation state that can provide a path for mechanistically accounting for NPQ variability and, subsequently, retrieving information on iron stress in global phytoplankton populations.

O'Malley, Robert T.; Behrenfeld, Michael J.; Westberry, Toby K.; Milligan, Allen J.; Shang, Shaoling; Yan, Jing

2014-07-01

50

Geostationary Meteorological Satellite5 (GMS-5)  

Microsoft Academic Search

This paper describes mission features and development of the Geostationary Meteorological Satellite-5 (GMS-5). The purpose of GMS series is the improvement of Japan's meteorological services and the development of meteorological satellite technology. The satellites have been used for the World Weather Watch (WWW) program planned by the World Meteorological Organization (WMO). The first satellite in this series was launched into

Koichi Kimura; Hideo Sakabe; Takao Suzuki; Motoi Okawara

1992-01-01

51

A universal on-orbit servicing system used in the geostationary orbit  

Microsoft Academic Search

The geostationary orbit (GEO), a unique satellite orbit of the human beings, is a very precious orbit resource. However, the continuous increasing of GEO debris makes the GEO orbit more and more crowded. Moreover, the failures of GEO spacecrafts will result in large economic cost and other bad impacts. In this paper, we proposed a space robotic servicing system, and

Wenfu Xu; Bin Liang; Bing Li; Yangsheng Xu

2011-01-01

52

Weather Satellite and Orbits  

NSDL National Science Digital Library

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

53

Geostationary operational environmental satellite /GOES/ - A multifunctional satellite  

NASA Technical Reports Server (NTRS)

The GOES satellites are multifunctional satellites whose primary function is to provide continuous measurements of the earth's surface and atmosphere from two geostationary orbit locations: 75 deg W and 135 deg W. This objective is accomplished with the visible infrared spin scan radiometer Atmospheric Sounder (VAS), and the Space Environment Monitor (SEM), which includes three instruments: a magnetometer, solar X-ray sensor, and an energetic particle sensor, which monitor the near earth space environment. The satellite's communication system provides several user oriented functions, including: (1) Transmission of VAS data; (2) Transmission of SEM data; (3) Transponder capabilities for stretched VAS (SVAS) data, weather facsimile (WEFAX) data, and trilateration signals; (4) transponder capabilities for data collection platform interrogation and data collection platform reply.

Mallette, L. A.

1982-01-01

54

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

Code of Federal Regulations, 2012 CFR

...Network Operations in the Fixed Satellite Service (FSS) Bands. 25...261 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards §...

2012-10-01

55

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

Code of Federal Regulations, 2014 CFR

...Network Operations in the Fixed-Satellite Service (FSS) Bands. 25...261 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards §...

2014-10-01

56

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

Code of Federal Regulations, 2010 CFR

...Network Operations in the Fixed Satellite Service (FSS) Bands. 25...261 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards §...

2010-10-01

57

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

Code of Federal Regulations, 2011 CFR

...Network Operations in the Fixed Satellite Service (FSS) Bands. 25...261 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards §...

2011-10-01

58

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

Code of Federal Regulations, 2013 CFR

...Network Operations in the Fixed-Satellite Service (FSS) Bands. 25...261 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards §...

2013-10-01

59

COMBINED USE OF POLAR ORBITING AND GEOSTATIONARY SATELLITES TO IMPROVE TIME INTERPOLATION IN DYNAMIC CROP MODELS FOR FOOD SECURITY ASSESSMENT  

Microsoft Academic Search

Use of satellite data in crop growth monitoring could provide great value for regional food security assessments. By using the difference between remotely sensed crop canopy temperature and the corresponding ambient temperature at the time of the satellite overpass the daily actual rate of transpiration can be inferred. This relationship allows adjustment of the actual rate of assimilation and hence

V. Venus; D. Rugege

60

The effectiveness of end-of-life re-orbiting for debris mitigation in geostationary orbit  

Microsoft Academic Search

The effect of satellite breakups over 72 years, as a function of the end-of-life re-orbiting altitude (0–2000?km), was analyzed in terms of fragment contribution to the object density in the geostationary orbit (GEO) ring, both in the short- and long-term. In the short-term, the explosions in GEO are the most detrimental for the GEO ring environment, though the average fragment

C. Pardini; L. Anselmo

1999-01-01

61

Interferometric imaging of geostationary satellites  

NASA Astrophysics Data System (ADS)

Even the longest geosatellite, at 40 m, subtends only 0.2 arcsec (1 microradian). Determining structure and orientation with 10 cm resolution requires a 90 m telescope at visual wavelengths, or an interferometer. We de- scribe the application of optical interferometry to observations of complex extended targets such as geosatellites, and discuss some of its challenges. We brie y describe our Navy Optical Interferometer (NOI) group's eorts toward interferometric observations of geosatellites, including the rst interferometric detection of a geosatellite. The NOI observes in 16 spectral channels (550{850 nm) using up to six 12-cm apertures, with baselines (separa- tions between apertures) of 16 to 79 m. We detected the geosatellite DirecTV-9S during glint seasons in March 2008 and March 2009, using a single 16 m baseline (resolution 1:6 m). Fringes on a longer baseline were too weak because the large-scale structure was over-resolved. The fringe strengths are consistent with a combination of two size scales, 1:3 m and & 3:5 m. Our near term NOI work is directed toward observing geosatellites with three or more 10 to 15 m baselines, using closure phase measurements to remove atmospheric turbulence eects and coherent data averaging to increase the SNR. Beyond the two- to three-year time frame, we plan to install larger apertures (1.4 and 1.8 m), allowing observations outside glint season, and to develop baseline bootstrap- ping, building long baselines from chains of short baselines, to avoid over-resolution while increasing maximum resolution. Our ultimate goal is to develop the design parameters for dedicated satellite imaging interferometry.

Armstrong, J. T.; Baines, E. K.; Hindsley, R. B.; Schmitt, H. R.; Restaino, S. R.; Jorgensen, A. M.; Mozurkewich, D.

2012-06-01

62

Normalization and calibration of geostationary satellite radiances for the International Satellite Cloud Climatology Project  

NASA Technical Reports Server (NTRS)

Procedures are described for normalizing the radiometric calibration of image radiances obtained from geostationary weather satellites that contributed data to the International Satellite Cloud Climatology Project. The key step is comparison of coincident and collocated measurements made by each satellite and the concurrent AVHRR on the 'afternoon' NOAA polar-orbiting weather satellite at the same viewing geometry. The results of this comparison allow transfer of the AVHRR absolute calibration, which has been established over the whole series, to the radiometers on the geostationary satellites. Results are given for Meteosat-2, 3, and 4, for GOES-5, 6, and 7, for GMS-2, 3, and 4 and for Insat-1B. The relative stability of the calibrations of these radiance data is estimated to be within +/- 3 percent; the uncertainty of the absolute calibrations is estimated to be less than 10 percent. The remaining uncertainties are at least two times smaller than for the original radiance data.

Desormeaux, Yves; Rossow, William B.; Brest, Christopher L.; Campbell, G. G.

1993-01-01

63

Towards high temporal and moderate spatial resolutions in the remote sensing retrieval of evapotranspiration by combining geostationary and polar orbit satellite data  

NASA Astrophysics Data System (ADS)

Evapotranspiration (ET) is the water flux going from the surface into the atmosphere as result of soil and surface water evaporation and plant transpiration. It constitutes a key component of the water cycle and its quantification is of crucial importance for a number of applications like water management, climatic modelling, agriculture monitoring and planning, etc. Estimating ET is not an easy task; specially if large areas are envisaged and various spatio-temporal patterns of ET are present as result of heterogeneity in land cover, land use and climatic conditions. In this respect, spaceborne remote sensing (RS) provides the only alternative to continuously measure surface parameters related to ET over large areas. The Royal Meteorological Institute (RMI) of Belgium, in the framework of EUMETSAT's "Land Surface Analysis-Satellite Application Facility" (LSA-SAF), has developed a model for the estimation of ET. The model is forced by RS data, numerical weather predictions and land cover information. The RS forcing is derived from measurements by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard the Meteosat Second Generation (MSG) satellite. This ET model is operational and delivers ET estimations over the whole field of view of the MSG satellite (Europe, Africa and Eastern South America) (http://landsaf.meteo.pt) every 30 minutes. The spatial resolution of MSG is 3 x 3 km at subsatellite point and about 4 x 5 km in continental Europe. The spatial resolution of this product may constrain its full exploitation as the interest of potential users (farmers and natural resources scientists) may lie on smaller spatial units. This study aimed at testing methodological alternatives to combine RS imagery (geostationary and polar orbit satellites) for the estimation of ET such that the spatial resolution of the final product is improved. In particular, the study consisted in the implementation of two approaches for combining the current ET estimations with RS data containing information over vegetation parameters and captured by polar orbit spaceborne sensors. The first tested approach consisted in forcing the operational ET algorithm with RS measurements obtained from a moderate spatial resolution sensor. The variables with improved spatial resolution were leaf area index and albedo. Other variables of the model remained unchanged with respect to the operational version. In the second approach, a two phases procedure was implemented. Firstly, a preliminary approximation of ET was obtained as a function of solar radiation, air temperature and a vegetation index. The value was then statistically adjusted on the basis of the ET estimations by the operational algorithm. The results of implementing the different approaches were tested against eddy covariance ET derived from measurements in Fluxnet towers spread across Europe and representing different landscape characteristics. The analysis allowed the identification of pros and cons of the tested methodological approaches as well as their performance in different land cover arrangements.

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

2014-05-01

64

Remote Sensing from Geostationary Orbit: GEO TROPSAT, A New Concept for Atmospheric Remote Sensing  

NASA Technical Reports Server (NTRS)

The Geostationary Tropospheric Pollution Satellite (GEO TROPSAT) mission is a new approach to measuring the critical constituents of tropospheric ozone chemistry: ozone, carbon monoxide, nitrogen dioxide, and aerosols. The GEO TROPSAT mission comprises a constellation of three instruments flying as secondary payloads on geostationary communications satellites around the world. This proposed approach can significantly reduce the cost of getting a science payload to geostationary orbit and also generates revenue for the satellite owners. The geostationary vantage point enables simultaneous high temporal and spatial resolution measurement of tropospheric trace gases, leading to greatly improved atmospheric ozone chemistry knowledge. The science data processing, conducted as a research (not operational) activity, will provide atmospheric trace gas data many times per day over the same region at better than 25 km ground footprint. The high temporal resolution identifies short time scale processes, diurnal variations, seasonal trends, and interannual variation.

Little, Alan D.; Neil, Doreen O.; Sachse, Glen W.; Fishman, Jack; Krueger, Arlin J.

1997-01-01

65

Orbit analysis of a geostationary gravitational wave interferometer detector array  

E-print Network

We analyze the trajectories of three geostationary satellites forming the GEOstationary GRAvitational Wave Interferometer (GEOGRAWI)~\\cite{tinto}, a space-based laser interferometer mission aiming to detect and study gravitational radiation in the ($10^{-4} - 10$) Hz band. The combined effects of the gravity fields of the Earth, the Sun and the Moon make the three satellites deviate from their nominally stationary, equatorial and equilateral configuration. Since changes in the satellites relative distances and orientations could negatively affect the precision of the laser heterodyne measurements, we have derived the time-dependence of the inter-satellite distances and velocities, the variations of the polar angles made by the constellation's three arms with respect to a chosen reference frame, and the time changes of the triangle's enclosed angles. We find that, during the time between two consecutive station-keeping maneuvers (about two weeks), the relative variations of the inter-satellite distances do not exceed a value of $0.05$ percent, while the relative velocities between pairs of satellites remain smaller than about $0.7 \\ {\\rm m/s}$. In addition, we find the angles made by the arms of the triangle with the equatorial plane to be periodic functions of time whose amplitudes grow linearly with time; the maximum variations experienced by these angles as well as by those within the triangle remain smaller than $3$ arc-minutes, while the East-West angular variations of the three arms remain smaller than about $15$ arc-minutes during the two-weeks period. The relatively small variations of these orbit parameters result into a set of system functional and performance requirements that are less stringent than those characterizing an interplanetary mission.

Massimo Tinto; Jose C. N. de Araujo; Helio K. Kuga; Marcio E. S. Alves; Odylio D. Aguiar

2014-10-11

66

The geostationary operational environmental satellite /GOES/ imaging communication system  

NASA Technical Reports Server (NTRS)

The SMS/GOES Satellite obtains day and night weather information from synchronous geostationary orbit by means of (1) earth imaging, (2) collection of environmental data from ground based sensors, platforms, and (3) monitoring of the space environment. SMS-1 and SMS-2 have been in orbit for 17 months and 8 months, respectively, and are presently taking full earth disk images in the visible and infrared every 30 minutes. SMS-1 is positioned to cover the eastern portion of the U.S. while SMS-2 is positioned to cover the western portion. This paper provides a general overview of the imaging communication portions of the SMS/GOES, related to the image data encoding and transmission as well as the method of the data time multiplexing and the manner in which the scan line to line synchronization is achieved.

Baker, W. L.; Savides, J.

1975-01-01

67

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

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

68

A universal on-orbit servicing system used in the geostationary orbit  

NASA Astrophysics Data System (ADS)

The geostationary orbit (GEO), a unique satellite orbit of the human beings, is a very precious orbit resource. However, the continuous increasing of GEO debris makes the GEO orbit more and more crowded. Moreover, the failures of GEO spacecrafts will result in large economic cost and other bad impacts. In this paper, we proposed a space robotic servicing system, and developed key pose (position and orientation) measurement and control algorithm. Firstly, the necessity of orbit service in GEO was analyzed. Then, a servicing concept for GEO non-cooperative targets was presented and a universal space robotic servicing system was designed. The system has a 2-DOF docking mechanism, a 7-DOF redundant manipulator and a set of stereo vision, in addition to the traditional subsystems of a spacecraft. This system can serve most existing satellites in GEO, not requiring specially designed objects for grappling and measuring on the target. The servicing contents include: (a) visual inspecting; (b) target tracking, approaching and docking; (c) ORUs (Orbital Replacement Units) replacement; (d) Malfunctioned mechanism deploying; (e) satellites life extension by taking over its control, or re-orbiting the abandoned satellites. As an example, the servicing mission of a malfunctioned GEO satellite with three severe mechanical failures was designed and simulated. The results showed the validity and flexibility of the proposed system.

Xu, Wenfu; Liang, Bin; Li, Bing; Xu, Yangsheng

2011-07-01

69

High Temporal and Spatial Resolution Coverage of Earth from Commercial AVSTAR Systems in Geostationary Orbit  

Microsoft Academic Search

Imaging the earth from Geostationary Earth Orbit (GEO) allows frequent updates of environmental conditions within an observable hemisphere at time and spatial scales appropriate to the most transient observable terrestrial phenomena. Coverage provided by current GEO Meteorological Satellites (METSATS) fails to fully exploit this advantage due primarily to obsolescent technology and also institutional inertia. With the full benefit of GEO

M. A. Lecompte; J. F. Heaps; F. H. Williams

2002-01-01

70

Two different attitude control methods for geostationary communication broadcasting satellite  

NASA Astrophysics Data System (ADS)

In this paper, two different attitude control methods for the geostationary satellite - attitude control by satellite-ground loop and autonomous attitude control on board are discussed. Attitude controls of the Chinese satellites STW-1 and STW-2 are described. The design of the attitude control system for three-axis-stabilized spacecraft is also discussed.

Lu, Zhenduo

1990-02-01

71

Studies of soundings and imagings measurements from geostationary satellites  

NASA Technical Reports Server (NTRS)

Soundings and imaging measurements from geostationary satellites are presented. The subjects discussed are: (1) meteorological data processing techniques, (2) sun glitter, (3) cloud growth rate study, satellite stability characteristics, and (4) high resolution optics. The use of perturbation technique to obtain the motion of sensors aboard a satellite is described. The most conditions, and measurement errors. Several performance evaluation parameters are proposed.

Suomi, V. E.

1973-01-01

72

High Speed Internet Access Through Unidirectional Geostationary Satellite Channels  

E-print Network

. Communication over satellite links is often characterized by sporadic high bit-error rates and burst lossesHigh Speed Internet Access Through Unidirectional Geostationary Satellite Channels Ina Minei Reuven user to a direct satellite channel, at a speed 20 times faster than that of an average telephone modem

Cohen, Reuven

73

Solely EP based Orbit Control System on Small GEO Satellite  

Microsoft Academic Search

SGEO offers a highly flexible and modular geostationary platform, able to accommodate a wide range of payloads in the range of 300 kg and 3 kW. SGEO is the first Western satellite relying solely on electrical propulsion for all orbit control tasks after direct injection into geostationary orbit. Optional, an Apogee Engine Module based on chemical propulsion will provide the

H. Lübberstedt; P. Rathsman; J. Kugelberg

74

Downburst prediction applications of meteorological geostationary satellites  

NASA Astrophysics Data System (ADS)

A suite of products has been developed and evaluated to assess hazards presented by convective storm downbursts derived from the current generation of Geostationary Operational Environmental Satellite (GOES) (13-15). The existing suite of GOES downburst prediction products employs the GOES sounder to calculate risk based on conceptual models of favorable environmental profiles for convective downburst generation. A diagnostic nowcasting product, the Microburst Windspeed Potential Index (MWPI), is designed to infer attributes of a favorable downburst environment: 1) the presence of large convective available potential energy (CAPE), and 2) the presence of a surface-based or elevated mixed layer with a steep temperature lapse rate and vertical relative humidity gradient. These conditions foster intense convective downdrafts upon the interaction of sub-saturated air in the elevated or sub-cloud mixed layer with the storm precipitation core. This paper provides an updated assessment of the MWPI algorithm, presents recent case studies demonstrating effective operational use of the MWPI product over the Atlantic coastal region, and presents validation results for the United States Great Plains and Mid-Atlantic coastal region. In addition, an application of the brightness temperature difference (BTD) between GOES imager water vapor (6.5?m) and thermal infrared (11?m) channels that identifies regions where downbursts are likely to develop, due to mid-tropospheric dry air entrainment, will be outlined.

Pryor, Kenneth L.

2014-11-01

75

An evaluation of Protocol Enhancing Proxies and modern file transport protocols for geostationary satellite communication  

Microsoft Academic Search

NASA is utilizing Global Hawk aircraft in high-altitude, long duration Earth science missions. Communications with the science payload is via Ku-Band satellites in geostationary orbits. All payload communications use standard Internet Protocols and routing, and much of the data to be transferred is comprised of very large files. The science community is interested in fully utilizing these communication links to

Patrick E. Finch; Donald V. Sullivan; William D. Ivancic

2012-01-01

76

Crew Transfer Options for Servicing of Geostationary Satellites  

NASA Technical Reports Server (NTRS)

In 2011, NASA and DARPA undertook a study to examine capabilities and system architecture options which could be used to provide manned servicing of satellites in Geostationary Earth Orbit (GEO). The study focused on understanding the generic nature of the problem and examining technology requirements, it was not for the purpose of proposing or justifying particular solutions. A portion of this study focused on assessing possible capabilities to efficiently transfer crew between Earth, Low Earth Orbit (LEO), and GEO satellite servicing locations. This report summarizes the crew transfer aspects of manned GEO satellite servicing. Direct placement of crew via capsule vehicles was compared to concepts of operation which divided crew transfer into multiple legs, first between earth and LEO and second between LEO and GEO. In space maneuvering via purely propulsive means was compared to in-space maneuvering which utilized aerobraking maneuvers for return to LEO from GEO. LEO waypoint locations such as equatorial, Kennedy Space Center, and International Space Station inclinations were compared. A discussion of operational concepts is followed by a discussion of appropriate areas for technology development.

Cerro, Jeffrey A.

2012-01-01

77

The geostationary environment measurement spectrometer (GEMS) mission in view of ozone detection: Possibility analysis and comparison with the geosynchronous orbit  

NASA Astrophysics Data System (ADS)

The United States, Europe, Japan, and Korea are planned to launch a geostationary satellite carrying the UV-VIS spectrometer in 2017-2018. This study is concerned with research program to develop ozone retrieval algorithm in Korean geostationary mission (GEMS, 120E). We compare the daily frequency of clear-sky scene from the collocated OMI and MTSAT reflectance products, which demonstrate that the sub-hourly observation could assure 50.2 ± 11.5% better spatial continuity than daily observation. The geostationary orbit has extreme satellite zenith angle at high latitudes and far west-east area, and large solar zenith angles around sunrise or sunset. This extreme data will make it difficult to retrieve ozone with good accuracy. Chance suggested geosynchronous orbit in form of “figure-eight”. In contrast to geostationary satellite, geosynchronous satellites could move to where we are interesting due to their non-zero inclination. We compare the sensitivity of the current ozone retrieval algorithm to geostationary orbit with that of geosynchronous orbit, which is emphasized on first attempt. This result indicates that for low and sub-mid latitude areas there are insignificant improvement less 10% between geosynchronous and geostationary orbit platforms and whereas become important over high latitude.

Park, S. J.; Kim, J. H.

2010-12-01

78

Studies of soundings and imaging measurements from geostationary satellites  

NASA Technical Reports Server (NTRS)

Soundings and imaging measurements obtained from geostationary satellites for the period 1 Nov. 1972 to 31 Jan. 1973 are reported. The subjects discussed are: (1) investigation of meteorological data processing techniques, (2) sun glitter, (3) cloud growth rate, and (4) comparative studies in satellite stability.

Suomi, V. E.

1973-01-01

79

Advanced Propulsion for Geostationary Orbit Insertion and North-South Station Keeping  

NASA Technical Reports Server (NTRS)

Solar electric propulsion technology is currently being used for geostationary satellite station keeping. Analyses show that electric propulsion technologies can be used to obtain additional increases in payload mass by using them to perform part of the orbit transfer. Three electric propulsion technologies are examined at two power levels for geostationary insertion of an Atlas IIAS class spacecraft. The onboard chemical propulsion apogee engine fuel is reduced in this analysis to allow the use of electric propulsion. A numerical optimizer is used to determine the chemical burns that will minimize the electric propulsion transfer times. For a 1550-kg Atlas IIAS class payload, increases in net mass (geostationary satellite mass less wet propulsion system mass) of 150-800 kg are enabled by using electric propulsion for station keeping, advanced chemical engines for part of the transfer, and electric propulsion for the remainder of the transfer. Trip times are between one and four months.

Oleson, Steven R.; Myers, Roger M.; Kluever, Craig A.; Riehl, John P.; Curran, Francis M.

1997-01-01

80

Precipitation estimations from geostationary orbit and prospects for METEOSAT Second Generation  

NASA Astrophysics Data System (ADS)

For over two decades operational rainfall estimations from geostationary satellites have represented an ambitious aspiration of scientists and an identified need of operational meteorologists. A wide variety of infrared and combined visible and infrared methods have been proposed for the identification of suitable relationships between satellite-observed cloud top radiative features and rainfall at the ground. Microwave-based retrievals, however, correlate rainfall and internal cloud microphysical features more successfully. The most significant limitation, however, is the indirect character of the retrieval that correlates microphysical and dynamical cloud characteristics with rain amounts at ground level. METEOSAT Second Generation signals a new era for geostationary satellites with its new 12 channel imager SEVIRI and 15 minute full-disk image repeat cycle. SEVIRI is expected to contribute significantly to a better characterisation of clouds and atmospheric stability by means of improved infrared calibration, radiometric performances, imaging frequency and multispectral image analysis. The significant increase of multispectral cloud observations is expected to provide new data for the improvement of rainfall estimations from geostationary orbit. The anticipated progress from enhanced imaging frequency and multispectral data for the definition of new techniques is discussed. Considerations for operational applications, chiefly for nowcasting, are also provided as they are the main goal of the satellite. Future developments and synergies with other geostationary and polar orbiting instruments, passive and active, are finally considered as the ultimate strategy for more accurate instantaneous rainfall estimations at all latitudes.

Levizzani, V.; Schmetz, J.; Lutz, H. J.; Kerkmann, J.; Alberoni, P. P.; Cervino, M.

2001-03-01

81

47 CFR 25.143 - Licensing provisions for the 1.6/2.4 GHz Mobile-Satellite Service and 2 GHz Mobile-Satellite...  

Code of Federal Regulations, 2014 CFR

...blanket” license. In the case of non-geostationary satellites...of orbital planes. In the case of geostationary satellites...geostationary/non-geostationary hybrid satellite system, an individual...prohibits a charge for the transmission of maritime distress...

2014-10-01

82

Cloud Property Retrievals from Geostationary Satellites for Aviation Weather Applications  

NASA Astrophysics Data System (ADS)

A near-real time analysis system has been developed to retrieve cloud and radiation properties from operational geostationary satellite imager data. It is currently being applied to GOES-11/12, Meteosat-9, and MTSAT-1R, as well as to polar orbiting satellite imagers. The North American domain, which includes much of Canada, the USA, and Mexico, is analyzed each half hour using data from GOES-11 and 12. Selected cloud properties including cloud phase, effective particle size, top and base heights, optical depth, and ice/liquid water path are made available digitally for use in an aircraft icing potential product and in numerical weather prediction model assimilation. In addition to their use in the Current Icing Potential Product, the analysis system generates a nowcasting aircraft icing index and estimate of ceiling heights. Recent advances to these analyses include improved nighttime retrievals and daytime multilayer cloud retrievals. The latter has significantly increased the amount of usable data for detection of icing conditions. These products and many others are also made available online in digital and image formats for use by other researchers, forecasters and the public. This paper will present examples of the results and validation efforts to date.

Minnis, P.; Palikonda, R.; Smith, W. L.; Chee, T.; Spangenberg, D. A.; Ayers, J. K.; Chang, F.-L.; Heck, P. W.

2009-09-01

83

Geostationary satellite detection of bio mass burning in South America  

Microsoft Academic Search

This paper presents the results of using Geostationary Operational Environmental Satellite (GOES) Visible Infrared Spin Scan Radiometer Atmospheric Sounder (VAS) data to monitor biomass burning associated with deforestation and grassland management in South America. The technique of Matson and Dozier has been adapted to GOES VAS short-wave and long-wave infrared window data to determine ihe size and temperature of fires

E. M. PRINS; W. P. MENZEL

1992-01-01

84

Operational performance report on Japan's geostationary meteorological satellite \\/GMS  

Microsoft Academic Search

Japan's Geostationary Meteorological Satellite (GMS) was launched by a Delta 2914 launch vehicle from the Eastern Test Range in the United States on July 14, 1977 and stationed at 140 E longitude over the equator. The GMS, appropriately named the Himawari, a sunflower, is a part of the World Weather Watch program designed to upgrade and improve the accuracy of

T. Kotoh; H. Dosho; Y. Horikawa; M. Saitoh

1980-01-01

85

Performance Analysis of the HTTP Protocol on Geostationary Satellite Links  

NASA Technical Reports Server (NTRS)

Various issues associated with HTTP protocol on geostationary satellite links are presented in viewgraph form. Specific topics include: 1) Network reference points; 2) The HTTP 1.0 and 1.1 mechanisms; 3) Experimental setup; 4) TCP and HTTP configuration; 5) Modelling slow start and 6) Results and future work.

Krus, Hans; Allman, Mark; Griner, Jim; Tran, Diepchi

1998-01-01

86

McIDAS-V: A powerful visualization and data analysis tool for geostationary environmental satellites  

NASA Astrophysics Data System (ADS)

The University of Wisconsin's Space Science and Engineering Center (SSEC) has been at the forefront in developing data analysis and visualization tools for environmental satellite and other geophysical data. The fifth generation of the Man-computer Interactive Data Access System (McIDAS-V) is a java-based, open-source, freely available system for researchers and algorithm developers that is being adapted and expanded for use with advanced geostationary environmental satellite observations. A key attribute of analysis and visualization systems is access to and display of a large variety of geophysical data. Providing these capabilities for numerous data types provides users with powerful tools for merging information, comparison of products and evaluation. McIDAS-V provides unique capabilities that support creative techniques for developing and evaluating algorithms, visualizing data and products in 4 dimensions, and validating results. For geostationary applications, McIDAS-V provides visualization and analysis support for GOES, MSG, MTSAT and FY2 data. NOAA is supporting the McIDAS-V development program for ABI imagery and products for the GOES-R/S series, which will bring an advanced multi-spectral imager into geostationary orbit. Used together, the geostationary environmental satellites provide the user community with detailed global coverage with rapid update cycles. This poster and demonstration will provide an overview of McIDAS-V with demonstrations of the data acquisition, visualization and analysis tools to support the international geostationary environmental satellite programs. It will also present results from several research projects involving current and future environmental satellites, demonstrating how the McIDAS-V software can be used to acquire satellite and ancillary data, create multi--spectral products using both scripting and interactive data manipulation tools, and evaluate output through on-board validation techniques.;

Achtor, T. H.; Rink, T.; Straka, W.; Feltz, J.

2012-12-01

87

Earth-to-Geostationary Orbit Transportation for Space Solar Power System Development  

NASA Technical Reports Server (NTRS)

Space solar power satellites have the potential to provide abundant quantities of electricity for use on Earth. One concept, the Sun Tower, can be assembled in geostationary orbit from pieces transferred from Earth. The cost of transportation is one of the major hurdles to space solar power. This study found that autonomous solar-electric transfer is a good choice for the transportation from LEO to GEO.

Martin, James A.; Donahue, Benjamin B.; Lawrence, Schuyler C.; McClanahan, James A.; Carrington, Connie K. (Technical Monitor)

2000-01-01

88

In-orbit radiometric performance variations of geostationary ocean color imager  

NASA Astrophysics Data System (ADS)

Geostationary Ocean Color Imager (GOCI), a payload of the Communication, Ocean and Meteorology Satellite (COMS), is the world's first ocean color observation satellite in geostationary orbit. It was launched at Kourou Space Center in French Guiana in June 2010. The detector array in GOCI is custom CMOS Image sensor about 2 Mega-pixels, featuring rectangular pixel size to compensate for the Earth oblique projection. This satellite is being operated on geostationary orbit about 36,500km far from the earth; hence it can be more influenced by sun activities than the other on low Earth orbit. Especially, the detector is sensitive of heat and it may give rise to increasing the defective pixels. In this paper, radiometric performance variations have been analyzed through the time series analysis, using the offset parameters and detector temperature estimated in GOCI radiometric model. It is essential to monitor the overall sensitivity of GOCI sensor, and it will helpful to the radiometric calibration. In the result, we notified there was no great variation in time series of offset parameters after operating the GOCI in July 2010, but we monitored an anomaly by an operational event. One of them related to thermal electron showed slightly increasing trend and the diurnal variation by the sun energy. Although sun interferences are occurred sometimes, any significant anomaly isn't found. With these results of characterization, we find that GOCI has been carrying out stably in the aspect of radiometric performance, and expect that it will be kept during the mission life.

Lee, Sun-Ju; Cho, Seongick; Han, Hee-Jeong; Oh, Eunsong; Ryu, Joo-Hyung; Ahn, Yu-Hwan

2011-11-01

89

Retrieval and verification of fire radiative power using the Korean geostationary meteorological satellite  

NASA Astrophysics Data System (ADS)

Recently, frequency and strength of global wildfire are on the increase. The wildfire encourages the climate change through release of GHGs into the atmosphere over one time occur. The effect of wildfire GHGs can be estimate by FRP(fire radiative power), many research using the remote sensing are trying for its efficient produce. A satellite fire product including fire mask and FRP was produced by polar orbit satellite at first, thereafter it was expanded to geostationary satellites for continuous monitoring of wide areas. However, geostationary satellites observing in East Asia no got a standard to produce the fire product yet. This paper described a retrieval of FRP using the COMS(Communication, Ocean and Meteorological satellite) that is a Korean geostationary satellite. The COMS FRP was retrieved MIR(Middle infrared) radiance method which approaches by brightness temperature of single waveband. Our test was presented that large scale wildfires(FRP > 300MW and confidence level > 9) occurred in the each April. The COMS FRP showed MAE = 103.67 MW(16%) with the MODIS. This result represents much as possibility of the FRP in East Asia. This paper is expected to provide to baseline for the FRP in East Asia, and apply to biomass loss and estimate the GHGs. In addition, the COMS FRP will contribute to studies of aerosols, economic losses and ecosystem damages as basic data.

Kim, Dae-Sun; Lee, Yang-Won

2014-10-01

90

The Geostationary Fourier Transform Spectrometer  

Microsoft Academic Search

The Geostationary Fourier Transform Spectrometer (GeoFTS) is an imaging spectrometer designed for an earth science mission to measure key atmospheric trace gases and process tracers related to climate change and human activity. The GeoFTS instrument is a half meter cube size instrument designed to operate in geostationary orbit as a secondary “hosted” payload on a commercial geostationary satellite mission. The

Richard Key; Stanley Sander; Annmarie Eldering; David Rider; Jean-Francois Blavier; Dmitriy Bekker; Yen-Hung Wu; Ken Manatt

2012-01-01

91

Air Quality Science and Regulatory Efforts Require Geostationary Satellite Measurements  

NASA Technical Reports Server (NTRS)

Air quality scientists and regulatory agencies would benefit from the high spatial and temporal resolution trace gas and aerosol data that could be provided by instruments on a geostationary platform. More detailed time-resolved data from a geostationary platform could be used in tracking regional transport and in evaluating mesoscale air quality model performance in terms of photochemical evolution throughout the day. The diurnal cycle of photochemical pollutants is currently missing from the data provided by the current generation of atmospheric chemistry satellites which provide only one measurement per day. Often peak surface ozone mixing ratios are reached much earlier in the day during major regional pollution episodes than during local episodes due to downward mixing of ozone that had been transported above the boundary layer overnight. The regional air quality models often do not simulate this downward mixing well enough and underestimate surface ozone in regional episodes. Having high time-resolution geostationary data will make it possible to determine the magnitude of this lower-and mid-tropospheric transport that contributes to peak eight-hour average ozone and 24-hour average PM2.5 concentrations. We will show ozone and PM(sub 2.5) episodes from the CMAQ model and suggest ways in which geostationary satellite data would improve air quality forecasting. Current regulatory modeling is typically being performed at 12 km horizontal resolution. State and regional air quality regulators in regions with complex topography and/or land-sea breezes are anxious to move to 4-km or finer resolution simulations. Geostationary data at these or finer resolutions will be useful in evaluating such models.

Pickering, Kenneth E.; Allen, D. J.; Stehr, J. W.

2006-01-01

92

Spectral Investigation of the Geostationary Satellite Radiosignals  

Microsoft Academic Search

The work contains the results from measuring the spectra of amplitude fluctuations of K-band emission source placed on board of the Hot Bird satellite under the different tropospheric conditions. The attempt has been made to validate the observed effects theoretically. It has been concluded that transversal velocity motion of irregularity and nonstationarity of the troposphere parameters are the characteristics, which

G. A. Alexeyev; M. V. Belobrova; D. D. Khalameyda; I. M. Mytsenko

2007-01-01

93

New developments on atmospheric chemsitry remote sensing from geostationary orbit  

NASA Astrophysics Data System (ADS)

During the EUMETSATs post-MSG user consultation process requirements on measurements of the composition of the lower part of the atmosphere were identified and detailed in the last years. These requirements are mostly linked to the application area "Operational Chemical Applications and Air Quality monitoring". To address air quality issues from space there is a clear need for high spatially (< 10 km x 10 km) and temporally resolved (< hourly) measurements of the composition of the troposphere. This is recognised and described in a variety of documents issued by operational meteorological services like EUMETSAT, by governmental initiatives like GMES as well as by scientific initiatives. Nevertheless, no measurement system is currently in place to fulfil the relevant requirements. Measurements from Geostationary Orbit (GEO) offer a very attractive approach to the observation of the high tropospheric variability from space, as already demonstrated by meteorological applications. In response to the data needs, studies were performed during the last years to investigate the capabilities and technical feasibility of instrumentation and mission concepts in geostationary orbit to meet the above mentioned user requirements. This talk will summarise the results of a study investigating the capabilities of an instrument measuring the solar backscatter radiance to derive the chemical composition of the troposphere (O3, NO2, CO, HCHO, SO2, CO, Aerosol, etc.). The feasibility and limitations of the measurement concept will be discussed and it will be shown that important user requirements can be addressed and fulfilled by a geostationary atmospheric chemistry mission.

Bovensmann, H.; Eichmann, K. U.; Noel, S.; Rozanov, V.; Vountas, M.; Burrows, J. P.

94

A multibeam Earth station antenna for accessing satellites with inclined orbits  

Microsoft Academic Search

A multibeam antenna is being investigated that allows an enhanced view of the geostationary arc and hence permits access to satellites with inclined orbits. The antenna uses two reflectors in an offset Cassegrain configuration. Multibeam operation is achieved over a region about the geostationary arc by shaping both reflectors. Tracking satellites with this antenna is achieved by moving the feed

T. S. Bird; S. J. Barker; M. A. Sprey

1992-01-01

95

Satellites Orbiting Earth  

NSDL National Science Digital Library

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

96

Analysis of Galileo Style Geostationary Satellite Imaging: Image Reconstruction  

NASA Astrophysics Data System (ADS)

Earlier this year DARPA announced the Galileo project, with the conceptual idea of using optical interferometry to combine the light from two or more telescopes, with at least one of them being movable, to image geostationary satellites. This project aims at obtaining a NIIRS 8 image of a geosat with a resolution of 10cm. The design of this experiment creates challenging issues for the reconstruction of a satellite image. Among these issues are the lack of information about the absolute phase of the baselines, the difficulty to observe with short baselines, color differences between different satellite parts, and the time needed to obtain enough pointings to appropriately sample the UV-plane. We use simulations developed by our group to evaluate the effects of these issues on the reconstructed image quality, and the time required to reach the NIIRS 8 goal.

Schmitt, H.; Armstrong, J. T.; Baines, E. K.; Hindsley, R. B.; Jorgensen, A. M.; Mozurkewich, D.; Restaino, S. R.; van Belle, G.; Wilson, T. L.

2012-09-01

97

The Geostationary Operational Environmental Satellite (GOES) Product Generation System  

NASA Technical Reports Server (NTRS)

The Geostationary Operational Environmental Satellite (GOES) Product Generation System (GPGS) is introduced and described. GPGS is a set of computer programs developed and maintained at the Global Hydrology and Climate Center and is designed to generate meteorological data products using visible and infrared measurements from the GOES-East Imager and Sounder instruments. The products that are produced by GPGS are skin temperature, total precipitable water, cloud top pressure, cloud albedo, surface albedo, and surface insolation. A robust cloud mask is also generated. The retrieval methodology for each product is described to include algorithm descriptions and required inputs and outputs for the programs. Validation is supplied where applicable.

Haines, S. L.; Suggs, R. J.; Jedlovec, G. J.

2004-01-01

98

Simulation of the water regime for a vast agricultural region territory utilizing measurements from polar-orbital and geostationary meteorological satellites  

NASA Astrophysics Data System (ADS)

The model of land surface-atmosphere interaction has been developed to calculate the water and heat balance components for vast vegetation covered areas during the growing season. The model is adjusted to utilize estimates of the land surface and meteorological characteristics derived from satellite-based measurements of radiometers AVHRR/NOAA, MODIS/EOS Terra, Aqua, and SEVIRI/Meteosat-9. The studies have been conducted for the territory of the European Russia Central Black Earth Region (CCR) with area of 227,300 km2 comprising seven regions of the Russian Federation for years 2009-2012 vegetation seasons. The technologies of AVHRR and MODIS data thematic processing have been refined and adapted to the study region providing the retrieval of land surface temperature Tls and emissivity E, land-air temperature (temperature at vegetation cover level) Ta, normalized difference vegetation index NDVI, vegetation cover fraction B, as well as the leaf area index LAI. The updated linear regression estimators for Tls, Ta and LAI have been built using more representative training samples compiled for the above vegetation seasons. The updated software package has been applied for AVHRR data processing to generate named remote sensing products for various dates of the mentioned vegetation periods. On the base of special technology and Internet resources the remote sounding products (Tls, E, NDVI, LAI), derived from MODIS data and covering the CCR, have been downloaded from LP DAAC web-site for the same vegetation seasons. The new method and technology have been developed and adopted for the retrieval of Tls and E from SEVIRI data. The retrievals cover the region of interest and are produced at daylight and nighttime. Method provides the derivation of Tls and E from SEVIRI measurements carried out at three successive times (for example, at 11.00, 12.00, 13.00 UTC), classified as 100% cloud-free for the study region without accurate a priori knowledge of E. The validation of remote sensing data on Tls was carried out through comparison of SEVIRI-based Tls retrievals (after bias correction) with independent collocated Tls estimates generated at LSA SAF (Lisbon, Portugal). It gives monthly-averaged values of RMS deviation in the range of 1.1-2.1°C for various dates and times during the period June-August 2009-2012. In addition the new method and technology have been also developed and tested for the Ta retrievals from SEVIRI data at daylight and nighttime. To derive Ta, the SEVIRI-based Tls estimates were used together with previously found correlation relationship between Tls and Ta. A comparison with collocated in-situ Ta observations, made at the CCR territory weather shelters, gives RMS errors in the range 1.8-2.9°C for the standard synoptic times and 2009-2012 summer periods. The error level is comparable to that inherent for the best foreign analogues as well as for numerical weather forecasting schemes. Developed techniques to assimilate remote sensing data in the model include the following: - replacement the values of the model parameters LAI and B, determined by observations at agricultural meteorological stations, by their satellite-derived estimates. Adequacy of such replacement has been confirmed by the results of comparing time behaviors of LAI built by ground- and satellite-based data, as well as the ground-measured and satellite-derived values of Tls and Ta, and modeled and measured values of evapotranspiration Ev and soil moisture content W. - entering the values of Tls and Ta retrieved from all aforementioned satellite data into the model as the input variables instead of the respective ground-measured temperatures. Availability of the SEVIRI data of fine temporal resolution creates opportunity to calculate the water and heat balance components quite accurately. However, the lack of the long continuous SEVIRI data series (because of the cloudiness) restricts this opportunity in a large extent. - taking into account spatial variability of vegetation and meteorological characteristics when calculating the water and hea

Muzylev, Eugene; Uspensky, Alexander; Startseva, Zoya; Volkova, Elena; Kukharsky, Alexander; Uspensky, Sergey

2013-04-01

99

The geostationary Earth radiation budget (GERB) instrument on EUMETSAT's MSG satellite  

NASA Astrophysics Data System (ADS)

Geostationary Earth radiation budget (GERB) is an Announcement of Opportunity Instrument for EUMETSAT's Meteosat Second Generation (MSG) satellite. GERB will make accurate measurements of the Earth Radiation Budget from geostationary orbit, provide an absolute reference calibration for LEO Earth radiation budget instruments and allow studies of the energetics of atmospheric processes. By operating from geostationary orbit, measurements may be made many times a day, thereby providing essentially perfect diurnal sampling of the radiation balance between reflected and emitted radiance for that area of the globe within the field of view. GERB will thus complement other instruments which operate in low orbit and give complete global coverage, but with poor and biased time resolution. GERB measures infrared radiation in two wavelength bands: 0.32-4.0 and 0.32- 30 ?m, with a pixel element size of 44 km at sub-satellite point. This paper gives an overview of the project and concentrates on the design and development of the instrument and ground testing and calibration, and lessons learnt from a short time scale low-budget project. The instrument was delivered for integration on the MSG platform in April 1999 ready for the proposed launch in October 2000, which has now been delayed probably to early 2002. The ground segment is being undertaken by RAL and RMIB and produces near real-time data for meteorological applications in conjunction with the main MSG imager—SEVERI. Climate research and other applications which are being developed under a EU Framework IV pilot project will be served by fully processed data. Because of the relevance of the observations to climate change, it is planned to maintain an operating instrument in orbit for at least 3.5 years. Two further GERB instruments are being built for subsequent launches of MSG.

Sandford, M. C. W.; Allan, P. M.; Caldwell, M. E.; Delderfield, J.; Oliver, M. B.; Sawyer, E.; Harries, J. E.; Ashmall, J.; Brindley, H.; Kellock, S.; Mossavati, R.; Wrigley, R.; Llewellyn-Jones, D.; Blake, O.; Butcher, G.; Cole, R.; Nelms, N.; DeWitte, S.; Gloesener, P.; Fabbrizzi, F.

2003-12-01

100

Detection of a geostationary satellite with the Navy Prototype Optical Interferometer  

Microsoft Academic Search

We have detected a satellite via optical interferometry for the first time, using a 16 m baseline of the Navy Prototype Optical Interferometer (NPOI) to observe the geostationary communications satellite DirecTV-9S during the \\

J. T. Armstrong; R. B. Hindsley; H. R. Schmitt; F. J. Vrba; J. A. Benson; D. J. Hutter; R. T. Zavala

2010-01-01

101

A study of regional-scale variability of in situ and model-generated tropospheric trace gases: Insights into observational requirements for a satellite in geostationary orbit  

NASA Astrophysics Data System (ADS)

We examine the results from a regional-scale chemical-transport model with 4-km resolution to determine the spatial variability of trace gases on this scale. Model-derived variability statistics are generated using 1st-order structure functions and then compared with in situ trace gas measurements from a series of aircraft campaigns. The variability of the observations and the model-derived concentrations are found to be in reasonable agreement for O 3 and CO, but the model underestimates the observed variability of NO 2. Variability statistics are then calculated for model-derived tropospheric column integrals. These integrals are calculated for 0-10 km (representative of the entire tropospheric column), 0-2 km (representative of the planetary boundary layer, PBL) and 2-10 km (representative of the free troposphere, FT). For each of the species examined, the variability of the tropospheric column is generally controlled by the variability in the lowest 2 km. The degree of control for each trace gas, however, is different. Whereas NO 2 is completely dominated by PBL processes, CO variability in the FT contributes appreciably to the variability of the entire tropospheric column, suggesting that two independent pieces of information for CO would be most helpful for describing the variability of the entire tropospheric column. Likewise, the variability of an independent free tropospheric measurement of O 3 would provide additional insight into the observed variability of the entire column, but the amount of additional information provided by a separate FT measurement is not as beneficial to what was found for CO. We provide additional analyses to quantify relationships that can be used to better understand the model-derived structure functions and their dependence on grid size and time of day. Lastly we present a practical example of how this information may be used for guidance in the development of science requirements for future satellite instruments since measurements from these instruments must be able to resolve smaller scale gradients to be used successfully for air quality applications.

Fishman, Jack; Silverman, Morgan L.; Crawford, James H.; Creilson, John K.

2011-09-01

102

Investigation of water vapor motion winds from geostationary satellites  

NASA Technical Reports Server (NTRS)

Motions deduced in animated water vapor imagery from geostationary satellites can be used to infer wind fields in cloudless regimes. For the past several years, CIMSS has been exploring this potentially important source of global-scale wind information. Recently, METEOSAT-3 data has become routinely available to both the U.S. operational and research community. Compared with the current GOES satellite, the METEOSAT has a superior resolution (5 km vs. 16 km) in its water vapor channel. Preliminary work: at CIMSS has demonstrated that wind sets derived from METEOSAT water vapor imagery can provide important upper-tropospheric wind information in data void areas, and can positively impact numerical model guidance in meteorological applications. Specifically, hurricane track forecasts can be improved. Currently, we are exploring methods to further improve the derivation and quality of the water vapor wind sets.

Velden, Christopher

1993-01-01

103

Spacecraft flight control system design selection process for a geostationary communication satellite  

NASA Technical Reports Server (NTRS)

The Earth's first artificial satellite, Sputnik 1, slowly tumbled in orbit. The first U.S. satellite, Explorer 1, also tumbled out of control. Now, as we launch the Mars observer and the Cassini spacecraft, stability and control have become higher priorities. The flight control system design selection process is reviewed using as an example a geostationary communication satellite which is to have a life expectancy of 10 to 14 years. Disturbance torques including aerodynamic, magnetic, gravity gradient, solar, micrometeorite, debris, collision, and internal torques are assessed to quantify the disturbance environment so that the required compensating torque can be determined. Then control torque options, including passive versus active, momentum control, bias momentum, spin stabilization, dual spin, gravity gradient, magnetic, reaction wheels, control moment gyros, nutation dampers, inertia augmentation techniques, three-axis control, reactions control system (RCS), and RCS sizing, are considered. A flight control system design is then selected and preliminary stability criteria are met by the control gains selection.

Barret, C.

1992-01-01

104

The provision of spectrum for feeder links of non-geostationary mobile satellites  

NASA Technical Reports Server (NTRS)

The possibility of sharing spectrum in the 30/20 GHz band between geostationary fixed-satellite systems and feeder-links of low-earth orbit (LEO) mobile-satellite systems is addressed, taking into account that International Telecommunications Union (ITU) Radio Regulation 2613 would be a factor in such sharing. Interference into each network in both the uplink at 30 GHz and the downlink at 20 GHz is considered. It is determined that if sharing were to take place the mobile-satellite may have to cease transmission often for intervals up to 10 seconds, may have to use high-gain tracking antennas on its spacecraft, and may find it an advantage to use code-division multiple access. An alternate solution suggested is to designate a band 50 to 100 MHz wide at 28 and 18 GHz to be used primarily for feeder links to LEO systems.

Bowen, Robert R.

1993-01-01

105

A TEMPORAL MAP IN GEOSTATIONARY ORBIT: THE COVER ETCHING ON THE EchoStar XVI ARTIFACT  

SciTech Connect

Geostationary satellites are unique among orbital spacecraft in that they experience no appreciable atmospheric drag. After concluding their respective missions, geostationary spacecraft remain in orbit virtually in perpetuity. As such, they represent some of human civilization's longest lasting artifacts. With this in mind, the EchoStar XVI satellite, to be launched in fall 2012, will play host to a time capsule intended as a message for the deep future. Inspired in part by the Pioneer Plaque and Voyager Golden Records, the EchoStar XVI Artifact is a pair of gold-plated aluminum jackets housing a small silicon disk containing 100 photographs. The Cover Etching, the subject of this paper, is etched onto one of the two jackets. It is a temporal map consisting of a star chart, pulsar timings, and other information describing the epoch from which EchoStar XVI came. The pulsar sample consists of 13 rapidly rotating objects, 5 of which are especially stable, having spin periods <10 ms and extremely small spin-down rates. In this paper, we discuss our approach to the time map etched onto the cover and the scientific data shown on it, and we speculate on the uses that future scientists may have for its data. The other portions of the EchoStar XVI Artifact will be discussed elsewhere.

Weisberg, Joel M., E-mail: jweisber@carleton.edu [Department of Physics and Astronomy, Carleton College, Northfield, MN 55057 (United States); Paglen, Trevor, E-mail: trevor@paglen.com

2012-10-01

106

A Temporal Map in Geostationary Orbit: The Cover Etching on the EchoStar XVI Artifact  

E-print Network

Geostationary satellites are unique among orbital spacecraft in that they experience no appreciable atmospheric drag. After concluding their respective missions, geostationary spacecraft remain in orbit virtually in perpetuity. As such, they represent some of human civilization's longest lasting artifacts. With this in mind, the EchoStar XVI satellite, to be launched in fall 2012, will play host to a time capsule intended as a message for the deep future. Inspired in part by the Pioneer Plaque and Voyager Golden Records, the EchoStar XVI Artifact is a pair of gold-plated aluminum jackets housing a small silicon disc containing one hundred photographs. The Cover Etching, the subject of this paper, is etched onto one of the two jackets. It is a temporal map consisting of a star chart, pulsar timings, and other information describing the epoch from which EchoStar XVI came. The pulsar sample consists of 13 rapidly rotating objects, 5 of which are especially stable, having spin periods < 10 ms and extremely sma...

Weisberg, J M

2012-01-01

107

A model for the geostationary orbital infrastructure, system analysis  

NASA Astrophysics Data System (ADS)

The functions and architecture of an infrastructure in the geostationary orbit (GEO) are discussed. A case study of a typical GEO infrastructure as it may develop during the next century was carried out, emphasizing conceptual design and analysis of a subsystem of this GEO infrastructure: the GEO Regional Transportation Company (GRET) envisaged as a commercial enterprise serving the 39 routes within the GEO complex by 10 different types of robots, taxis, and tugs. Results of simulation runs over a 110 yr life cycle produce timelines of several system performance parameters including prices for services within the market scenario assumed, which includes the acquisition and operation of a solar power system with 500 GW output.

Koelle, H. H.; Millin, N.

1988-08-01

108

Geostationary orbits from mid-latitude launch sites via lunar gravity assist  

NASA Astrophysics Data System (ADS)

The out-of-plane maneuver, necessary to acquire a geostationary orbit from launch sites that are at some degrees of latitude, makes the cost of such a mission very high. In this paper, we present a trajectory design for reaching a geostationary orbit from a mid-latitude launch base, with a consistent saving of propellant. This has been obtained using a lunar gravity assist (g.a.) to change the high inclination of the satellite orbit and, at the same time, to raise the perigee to the geosynchronous height. The Moon g.a. has been designed, describing the physical process by means of Opik's method. This is an analytical approximation technique which allows computation of outcome of planetary close encounters in a simple, but accurate, way. The trajectory resulting from this preliminary study has been used as a starting point for a numerical integration, using Everhart's integrator RADAU. We considered also the launch from Cape Canaveral (28.5 deg North), finding a small saving of V. The mission sequences are described and compared to other traditional trajectory designs.

Graziani, F.; Castronuovo, M. M.; Teofilatto, P.

109

Differential spacecraft charging on the geostationary operational environmental satellites  

NASA Astrophysics Data System (ADS)

Subsystems aboard the Geostationary Operational Environmental Satellites 4 and 5 showed instances of anomalous changes in state corresponding to false commands. Evidence linking the anomalous changes to geomagnetic activity, and presumably static discharges generated by spacecraft differential charging induced by substorm particle injection events is presented. The anomalies are shown to be correlated with individual substorms as monitored by stations of the North American Magnetometer Chain. The relative frequency of the anomalies is shown to be a function of geomagnetic activity. Finally a least squares fit to the time delay between substorm initiation and spacecraft anomaly as a function of spacecraft local time is shown to be consistent with injected electron populations with energy in the range 10 keV to 15 keV, in agreement with present understanding of the spacecraft charging mechanism. The spacecraft elements responsible for the differential charging were not satisfactorily identified. That question is currently under investigation.

Farthing, W. H.; Brown, J. P.; Bryant, W. C.

1982-03-01

110

Categorizing precipitating clouds by using radar and geostationary satellite  

NASA Astrophysics Data System (ADS)

The classification of precipitating cloud systems over Thailand was attempted by using radar reflectivity and Multifunctional Transport Satellites (MTSAT) infrared brightness temperature (TBB) data. The proposed method can classify the convective rain (CR) area, stratiform rain (SR) area and non-precipitation area such as cumulus and cirrus cloud by applying an integrating analysis of rain gauge, ground-based radar and geostationary satellite data. Since the present study focuses on precipitation, the classified results of precipitation area are used to estimate quantitative precipitation amount. To merge different rainfall products, the bias between the products should be removed. The bias correction method is used to estimate spatially varying multiplicative biases in hourly radar and satellite rainfall using a gauge and radar rainfall product, respectively. An extreme rain event was selected to obtain the multiplicative bias correction and to merge data set. Correlation coefficient (CC), root mean square error (RMSE) and mean bias are used to evaluate the performance of bias correction method. The combined radar-MTSAT method is a simple and useful method. This method has been successfully applied to merge radar and gauge rainfall for hydrological purpose.

Wetchayont, P.; Hayasaka, T.; Katagiri, S.; Satomura, T.

2012-11-01

111

Plans for EUMETSAT's Thrid Generation Meteosat (MTG) geostationary satellite program  

NASA Astrophysics Data System (ADS)

After movement of the first Meteosat Second Generation (MSG) satellite to 3.4 degree West by end of January 2004, the satellite has been renamed Meteosat-8 and the system has been declared fully operational. Meteosat-8 is now the primary European source of geostationary observations over Europe and Africa, as the first in a series of four satellites expected to deliver operational services at least until 2015. Considering the time required for the definition phases of new space systems their typical development cycle and the approval of complex programmes, it is necessary to plan for follow-up missions. EUMETSAT has therefore, as a first step in the preparation of the Third Generation Meteosat (MTG) European geostationary satellite system, established a USER Consultation Process aimed at capturing the foreseeable high-level user/service needs and priorities of the EUMETSAT customers and users in the 2015-2025 timeframe. This process was implemented through the set up of Applications Expert Groups (AEGs) tasked to propose their vision on operational services, to define associated needs and priorities for input information and observations. At the 1st Post-MSG User Consultation Workshop, November 2001, the work of the AEGs were presented to a broader user group serving as a basis for the identification of relevant observing techniques and the definition of requirements for the MTG observation missions. Currently, a total of five observation missions has been defined for pre-phase A studies at system level under ESA contract to be started in July 2004. Those are: High Resolution Fast Imagery Mission (successor to MSG SEVIRI HRV mission) Full Disk High Spectral Resolution Imagery Mission (successor to the mission of other SEVIRI channels) Lightning Imagery Mission IR Sounding Mission UV Sounding Mission Prior to the start of industry pre-phase A studies the joined ESA/EUMETSAT MTG Project Team, supported by an external group of experts named the MTG Mission Team, established the MTG Mission requirements document (MRD), to be released by 1st April. The presentation will give an overview on the current status of definition of the five observation missions, followed by a brief description of the MTG schedule and related milestones.

Stuhlmann, R. S.; Tjemkes, S. A. T.; Rodriguez, A. R. R.; Bézy, J. L. B.; Aminou, D. A.; Bensi, P. B.

112

Radiation Products based on a constellation of Geostationary Satellites  

NASA Astrophysics Data System (ADS)

The various components of the surface radiation budget present high variability in time and space, particularly over land surfaces where spatial heterogeneity of the upward fluxes is high. Geostationary satellites are well-suited to describe the daily cycle of downward and upward radiation fluxes and present spatial resolutions of the order of 3-to-5 km at sub-satellite point, acceptable for many applications. The work presented here is being carried out within the framework of Geoland-2 project, and aims the use of data from geostationary platforms to generate, archive and distribute in near real time four component of the surface radiation budget: land surface albedo, land surface temperature (LST) and downward short- and long-wave fluxes at the surface. All four components are retrieved from the following satellites - GOES-W covering North and South America, Meteosat Second Generation (MSG) covering essentially Europe and Africa, and MTSAT covering part of Asia and Australia. The variables are retrieved independently from each satellite and then merged into a single field, with a 5 km spatial resolution. Data are generated hourly in the case of the downward fluxes and LST, and 10-daily in the case of albedo. In regions covered by both GOES and MSG disks, the interpolated field makes use of both retrievals, giving more weight to those with lower uncertainty. The four components of the surface radiation budget described above are assessed through comparisons with similar parameters retrieved from other sensors (e.g., MODIS, CERES) or from models (e.g., ECMWF forecasts), as well as with in situ observations when available. The presentation will be focused on a brief description of algorithms and auxiliary data used in product estimation. The results of inter-comparisons with other data sources, along with the identification of the retrieval conditions that allow optimal / sub-optimal estimation of these surface radiation parameters will also be analysed. The radiation products generated within the Geoland-2 project are freely available to the user community.

Trigo, I. F.; Freitas, S. C.; Barroso, C.; Macedo, J.; Perdigão, R.; Silva, R.; Viterbo, P.

2012-04-01

113

Coherent radar measurement of ocean currents from geostationary orbit  

NASA Technical Reports Server (NTRS)

A coherent HF radar system developed by Barrick has successfully measured ocean surface currents near shore. This innovative system, called CODAR, can map the current vector for coastal areas as large as 10,000 sq km. CODAR's range is limited owing to the strong attenuation suffered by HF ground waves. An alternate technique was proposed by Schuler, in which the cross-product power spectrum of two (different frequency) microwave signals is processed. The frequency of the resonant peak corresponds close by to the Doppler shift of an ocean gravity wave traveling toward the radar at the phase velocity, v(sub p). The slight difference between the frequency of the measured resonant delta K peak and the Doppler frequency shift caused by the motion of the gravity wave is attributed to be the current velocity in the pointing direction of the radar. The Microwave Remote Sensing Laboratory (MIRSL) has considered the feasibility of using this technique to measure ocean surface currents from geostationary satellite platforms. Problems are discussed that must be overcome if a satellite current measurement system is to be realized. MIRSL research activities that address some of these problem areas are discussed. Current measurements are presented that were made using a specially-designed C-Band, step-frequency delta K radar. These measurements suggest that progress is being achieved in detecting ocean surface current motion for a wide variety of ocean surface conditions.

Mcintosh, R. E.

1989-01-01

114

Advanced Propulsion for Geostationary Orbit Insertion and North-South Station Keeping  

NASA Technical Reports Server (NTRS)

Solar electric propulsion (SEP) technology is currently being used for geostationary satellite station keeping to increase payload mass. Analyses show that advanced electric propulsion technologies can be used to obtain additional increases in payload mass by using these same technologies to perform part of the orbit transfer. In this work three electric propulsion technologies are examined at two power levels for an Atlas 2AS class spacecraft. The on-board chemical propulsion apogee engine fuel is reduced to allow the use of electric propulsion. A numerical optimizer is used to determine the chemical burns which will minimize the electric propulsion transfer time. Results show that for a 1550 kg Atlas 2AS class payload, increases in net mass (geostationary satellite mass less wet propulsion system mass) of 150 to 800 kg are possible using electric propulsion for station keeping, advanced chemical engines for part of the transfer, and electric propulsion for the remainder of the transfer. Trip times are between one and four months.

Oleson, Steven R.; Myers, Roger M.; Kluever, Craig A.; Riehl, John P.; Curran, Francis M.

1995-01-01

115

Our Understanding of Space Weather features responsible for geostationary satellite anamolies (P39)  

NASA Astrophysics Data System (ADS)

girija60@yahoo.com The topic of space weather effects on operational anomalies on spacecraft is one of considerable research investigation, with both pure and applied aspects. This is because of the very high costs involved in fabricating and operating spacecraft, and in insuring them against the harmful effects of space weather. This is more true for geostationary satellites than of low-orbiting spacecraft, as the former operate in the high-risk environment of the Earth’s outer radiation belts, with its large vagaries in spatial and time variations of high- energy electron and proton distributions (BAKER 2003). Without doubt, plasma and magnetic field emissions from active regions on the Sun are the root cause for spacecraft anomalies. Our study for 2005 shows that over 95% of anomalies can be related to some definite activity on the Sun, ranging from high-speed solar wind streams with their 27-day recurrence patterns/coronal holes/coronal mass ejections preceded by X or M type of flares/and magnetic cloud events. The most energetic solar activity events are generally accompanied by a large rise in solar MeV proton densities at geo-stationary orbit (WILKINSON 1994), and they account for definite anomalies classified as SEU (Single Event Upsets which most often are reversible through resetting commands). Any particles in the low energy ranges (eV and keV, and these could be of magnetospheric or ionospheric origin), are believed to cause external charging effects in exposed parts of the spacecraft such as solar power arrays and power cables. These mainly result in power losses which are debilitating over a period of time. The most dangerous and often irrecoverable damage is due to electronics in the 1-5 MeV range which cause deep dielectric discharge of arc type in semi-conductors comprising spacecraft instruments. Following major solar activity, the populations of these rise to more than (5x103) particles/cm2.ster.sec, with large spatial and time variations (LOVE et al. 2000). When the influence of these relativistic electrons in the neighborhood of geo-stationary spacecraft builds up to values exceeding 108/cm2.ster.day, satellite anomalies invariably occur.Our study finds that these ‘Relativistic electron events’ accompanied by satellite anomalies invariably occur following sharp, well-defined shocks in the inter-planetary medium, and we are trying to understand the relationship between the two. We also notice that anomalies due to space weather effects are very satellite-specific, with differing threshold values seen for different satellites.

Rajaram, G.; et al.

2006-11-01

116

Advanced Baseline Sounder (ABS) for future Geostationary Operational Environmental Satellites (GOES-R and beyond)  

E-print Network

. INTRODUCTION The first Geostationary Operational Environmental Satellite (GOES) that carried the VISSR (Visible scan radiometer. This evolution in the GOES system was termed GOES-VAS, VISSR Atmospheric Sounder

Li, Jun

117

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

Code of Federal Regulations, 2012 CFR

...license. In the case of non-geostationary...orbital planes. In the case of geostationary satellites...non-geostationary hybrid satellite system...domestic or transborder transmission, the amount of capacity...prohibits a charge for the transmission of maritime...

2012-10-01

118

Land surface thermal characterization of Asian-pacific region with Japanese geostationary satellite  

NASA Astrophysics Data System (ADS)

Land Surface Temperature (LST) is a significant indicator of energy balance at the Earth's surface. It is required for a wide variety of climate, hydrological, ecological, and biogeochemical studies. Although LST is highly variable both temporally and spatially, it is impossible for polar-orbiting satellite to detect hourly changes in LST, because the satellite is able to only collect data of the same area at most twice a day. On the other hand, geostationary satellite is able to collect hourly data and has a possibility to monitor hourly changes in LST, therefore hourly measurements of geostationary satellite enables us to characterize detailed thermal conditions of the Earth's surface and improve our understanding of the surface energy balance. Multi-functional Transport Satellite (MTSAT) is a Japanese geostationary satellite launched in 2005 and covers Asia-Pacific region. MTSAT provides hourly data with 5 bands including two thermal infrared (TIR) bands in the 10.5-12.5 micron region. In this research, we have developed a methodology to retrieve hourly LST from thermal infrared data of MTSAT. We applied Generalized Split-window (GSW) equation to estimate LST from TIR data. First, the brightness temperatures measured at sensor on MTSAT was simulated by radiative transfer code (MODTRAN), and the numerical coefficients of GSW equation were optimized based on the simulation results with non-linear minimization algorithm. The standard deviation of derived GSW equation was less than or equal to 1.09K in the case of viewing zenith angle lower than 40 degree and 1.73K in 60 degree. Then, spatial distributions of LST have been mapped optimized GSW equation with brightness temperatures of MTSAT IR1 and IR2 and emissivity map from MODIS product. Finally, these maps were validated with MODIS LST product (MOD11A1) over four Asian-pacific regions such as Bangkok, Tokyo, UlanBator and Jakarta , It is found that RMSE of these regions were 4.57K, 2.22K, 2.71K and 3.92K, respectively. Large RMSEs of Bangkok and Jakarta in the tropical zone can be result from unsuitable parameters used in the MODTRAN simulations and remained haze or cirrus cloud. However, comparison between MTSAT LST and MODIS LST showed linearity and consistency, therefore MTSAT LST contribute to a better understanding in a wide variety of the surface energy balance research. Finally, thermal characterizations such as the rate of LST change or diurnal LST range and so on have been mapped by using constructed MTSAT LST database.

Oyoshi, K.; Tamura, M.

2010-12-01

119

Low Earth Orbit satellite/terrestrial mobile service compatibility  

NASA Technical Reports Server (NTRS)

Currently the geostationary type of satellite is the only one used to provide commercial mobile-satellite communication services. Low earth orbit (LEO) satellite systems are now being proposed as a future alternative. By the implementation of LEO satellite systems, predicted at between 5 and 8 years time, mobile space/terrestrial technology will have progressed to the third generation stage of development. This paper considers the system issues that will need to be addressed when developing a dual mode terminal, enabling access to both terrestrial and LEO satellite systems.

Sheriff, Ray E.; Gardiner, John G.

1993-01-01

120

Relativistic electrons near geostationary orbit: Evidence for internal magnetospheric acceleration  

SciTech Connect

At times, relativistic electron fluxes in Earth's outer magnetosphere are not obviously related to an external (Jovian or solar) source. This finding suggests that an internal magnetospheric acceleration mechanism may operate under some circumstances. A possible mechanism identified for Jupiter's magnetosphere could also be considered in the terrestrial case. Such a model requires the substorm- generation of a spectrally-soft electron component with subsequent inward radial diffusion (violating the third adiabatic invariant). A large electron energy gain transverse to the magnetic field occurs in this process. Eventually, deep within the magnetosphere, substantial pitch angle scattering occurs violating all adiabatic invariants. Then, at low L-values, there occurs an energy-preserving outward transport of energetic electrons near the mirror points. This leads to a return of the accelerated population to the outer magnetosphere. Such low-altitude processes should result in ''conic'' or ''butterfly'' pitch angle distributions at very high energies as the electrons execute trans-L diffusion at the mirror altitudes and then are magnetically focussed near the equator. Data collected concurrently at geostationary orbit at three widely-spaced local times during a relativisic electron event show a butterfly pitch angle distribution, while lower energy electrons simultaneously show pancake-like distributions. The butterfly pitch angle distributions appear in /similar to/25% of the examined relativistic electron events, thereby providing support for acceleration by a recirculation process. /copyright/ American Geophysical Union 1989

Baker, D. N.; Blake, J. B.; Callis, L. B.; Belian, R. D.; Cayton, T. E.

1989-06-01

121

Validating an operational physical method to compute surface radiation from geostationary satellites  

NASA Astrophysics Data System (ADS)

Models to compute global horizontal irradiance (GHI) and direct normal irradiance (DNI) have been in development over the last three decades. These models can be classified as empirical or physical based on the approach. Empirical models relate ground-based observations with satellite measurements and use these relations to compute surface radiation. Physical models consider the physics behind the radiation received at the satellite and create retrievals to estimate surface radiation. While empirical methods have been traditionally used for computing surface radiation for the solar energy industry, the advent of faster computing has made operational physical models viable. The Global Solar Insolation Project (GSIP) is a physical model that computes DNI and GHI using the visible and infrared channel measurements from a weather satellite. GSIP uses a two-stage scheme that first retrieves cloud properties and uses those properties in a radiative transfer model to calculate GHI and DNI. Developed for polar orbiting satellites, GSIP has been adapted to NOAA's Geostationary Operation Environmental Satellite series and can run operationally at high spatial resolutions. This method holds the possibility of creating high quality datasets of GHI and DNI for use by the solar energy industry. We present an outline of the methodology and results from running the model as well as a validation study using ground-based instruments.

Sengupta, Manajit; Heidinger, Andrew; Miller, Steven

2010-08-01

122

Investigating the Use of Deep Convective Clouds (DCCT) to Monitor On-orbit Performance of the Geostationary Lightning Mapper (GLM) using Lightning Imaging Sensor (LIS) Measurements  

NASA Technical Reports Server (NTRS)

There is a need to monitor the on-orbit performance of the Geostationary Lightning Mapper (GLM) on the Geostationary Operational Environmental Satellite R (GOES-R) for changes in instrument calibration that will affect GLM's lightning detection efficiency. GLM has no onboard calibration so GLM background radiance observations (available every 2.5 min) of Deep Convective Clouds (DCCs) are investigated as invariant targets to monitor GLM performance. Observations from the Lightning Imaging Sensor (LIS) and the Visible and Infrared Scanner (VIRS) onboard the Tropical Rainfall Measuring Mission (TRMM) satellite are used as proxy datasets for GLM and ABI 11 m measurements.

Buechler, Dennis E.; Christian, Hugh J.; Koshak, William J.; Goodman, Steven J.

2013-01-01

123

Analysis of signal to noise ratio for atmospheric ultraviolet remote sensing on geostationary orbit with variations of solar incident angles  

NASA Astrophysics Data System (ADS)

Ultraviolet (UV) sensors on a geostationary orbit (GEO) have important potential value in atmospheric remote sensing, but the satellites orbit mode of it is quit different from sun-synchronous orbit satellites, which result in the significant diurnal and seasonal variations in radiation environment of earth observation and radiation signal of sensors, therefore, the effect to sensor radiometric performance, such as signal to noise ratio for atmospheric ultraviolet remote sensing caused by variations of solar angle is significant in the performance design of sensors. The synthetic ultraviolet sensor is set at the geostationary orbit, 36000 km away from the sea level of the Equator with 8.75 degree field of view, and the subsatellite track point of which is located at 90 degrees east longitude and Equator. The Satellite scanning angles (SA) from 0 to 8.648 degree that cover the earth surface are selected corresponding to the 10 degrees equal interval view zenith angle, and the SA from 8.648 to 8.785 degree cover the earth lamb 100 km far away from earth tangent point. Based on the MODTRAN4 model, on normal atmospheric conditions, the distributions of the UV upwelling radiance from surface or limb viewing path of the earth could be simulated with the change of sun's right ascension. Moreover, the average signal to noise ratio to the atmospheric sounding is obtained in different UV spectra using the Sensor signal to noise ratio model. The results show that the thresholds range, tendency and shape of signal to noise ratio have a variety of features affected by variation of Sun hour angles and declinations. These result and conclusions could contribute to performance design of UV sensors on the geostationary orbit.

Lyu, Chun-guang; Yang, Wen-bo; Tian, Qing-jiu; Zhou, Yang; Liu, Zong-ming; Zhang, Han-mo

2014-11-01

124

An LO Phase Link Using a Commercial Geo-Stationary Satellite  

NASA Technical Reports Server (NTRS)

This viewgraph presentation reviews an experiment to determine feasibility of achieving 1 ps level time transfer using a satellite link and make use of inexpensive Ku band transmit/receive equipment. It reviews the advantages of Two Way Satellite Time Transfer using a commercial Geo-Stationary Satellite: (1) Commercial satellites are available (2) Significant cost reduction when compared to Hydrogen Masers and (3) Large footprint- entire US (including Hawaii) with just one satellite.

Bardin, Joseph C.; Weinreb, Sander; Bagri, Durgadas S.

2005-01-01

125

SATELLITE CONSTELLATION NETWORKS The path from orbital geometry through network topology to  

E-print Network

for Communication Systems Research, University of Surrey; software engineer, Cisco Systems Ltd. Abstract: Satellite communication services; a satellite in geostationary orbit above the Equator cannot see more than 30. Satellite constellations have been proposed and implemented for use in communications, including networking

Wood, Lloyd

126

An application of a geostationary satellite rain estimation technique to an extratropical area  

NASA Technical Reports Server (NTRS)

Previous studies in which geostationary-satellite images were used for estimating precipitations dealt primarily with tropical clouds. In the present study, an attempt is made to evaluate the applicability of geostationary images and techniques in the Montreal area, characterized by a variety of weather situations and variables (different types of cloud, moisture and temperature profiles, and rain rates). The large differences between the Montreal and tropical studies are shown to be reflected by Simpson and Wiggert's (1969) cloud model.

Wylie, D. P.

1979-01-01

127

Factors affecting frequency and orbit utilization by high power transmission satellite systems  

NASA Technical Reports Server (NTRS)

The factors affecting the sharing of the geostationary orbit by high power (primarily television) satellite systems having the same or adjacent coverage areas and by satellites occupying the same orbit segment are examined and examples using the results of computer computations are given. The factors considered include: required protection ratio, receiver antenna patterns, relative transmitter power, transmitter antenna patterns, satellite grouping, and coverage pattern overlap. The results presented indicated the limits of system characteristics and orbit deployment which can result from mixing systems.

Kuhns, P. W.; Miller, E. F.; Malley, T. A.

1972-01-01

128

Factors affecting frequency and orbit utilization by high power transmission satellite systems.  

NASA Technical Reports Server (NTRS)

The factors affecting the sharing of the geostationary orbit by high power (primarily television) satellite systems having the same or adjacent coverage areas and by satellites occupying the same orbit segment are examined and examples using the results of computer computations are given. The factors considered include: required protection ratio, receiver antenna patterns, relative transmitter power, transmitter antenna patterns, satellite grouping, and coverage pattern overlap. The results presented indicate the limits of system characteristics and orbit deployment which can result from mixing systems.

Kuhns, P. W.; Miller, E. F.; O'Malley, T. A.

1972-01-01

129

Factors affecting frequency and orbit utilization by high power transmission satellite systems  

NASA Technical Reports Server (NTRS)

The factors affecting the sharing of the geostationary orbit by high power (primarily television) satellite systems having the same or adjacent coverage areas and by satellites occupying the same orbit segment are examined and examples using the results of computer computations are given. The factors considered include: required protection ratio, receiver antenna patterns, relative transmitter power, transmitter antenna patterns, satellite grouping, and coverage pattern overlap. The results presented indicate the limits of system characteristics and orbit deployment which can result from mixing systems.

Kuhns, P. W.; Miller, E.; Malley, T. A.

1972-01-01

130

A satellite system synthesis model for orbital arc allotment optimization  

NASA Technical Reports Server (NTRS)

A mixed integer programming formulation of a satellite system synthesis problem if presented, which is referred to as the arc allotment problem (AAP). Each satellite administration is to be allotted a weighted-length segment of the geostationary orbital arc within which its satellites may be positioned at any longitudes. The objective function maximizes the length of the unweighted arc segment allotted to every administration, subject to single-entry co-channel interference restrictions and constraints imposed by the visible arc for each administration. Useful relationships between special cases of AAP and another satellite synthesis problem are established. Solutions to two example problems are presented.

Reilly, Charles H.

1987-01-01

131

Field experiment on simple vehicle antenna system using geostationary test satellite  

Microsoft Academic Search

This paper presents a field experiment of simple developed antenna system for land vehicle use which was tested by use of the Japanese geostationary test satellite called the engineering test satellite-VIII (ETS-VIII). The antenna system was mounted in a vehicle is compact, light weight, and promising for low cost system. The antenna system was built by a planar array antenna

Basari; K. Saito; M. Takahashi; K. Ito

2009-01-01

132

Geostationary-satellite imagery applications on distributed, high-performance computing  

Microsoft Academic Search

We discuss applications of high resolution geostationary satellite imagery and distributed high performance computing facilities for the storage, processing and delivery of satellite data products. We describe our system which is built on a distributed high performance computing environment using a number of software infrastructural building blocks and computational resources interconnected by an ATM based broadband network. Distributed high performance

K. A. Hawick; H. A. James; K. J. Maciunas; F. A. Vaughan; A. L. Wendelborn; M. Buchhorn; M. Rezny; S. R. Taylor; M. D. Wilson

1997-01-01

133

Retrieval of Aerosol Optical Depth over East Asia from a Geostationary Satellite, MTSAT-1R  

NASA Astrophysics Data System (ADS)

Aerosol optical depth (AOD) retrieval from satellite remote sensing is essential to understand aerosol influence on earth climate system. An algorithm to retrieve AOD from geostationary earth orbit (GEO) satellite allows us to monitor sources, sinks and transport of aerosols in higher temporal resolution. In this study, using 30-day visible channel data from the Multi-Functional Transport Satellite-1 Replacement (MTSAT-1R) to estimate surface reflectance and DIScrete Ordinate Radiative (DISORT) model (6 S) to calculate look up tables (LUT), AODs are retrieved at 0.55 ?m over East Asia. The retrieved results are compared with the values of AERONET and MODIS. The calculated correlation coefficient(R) during March 2006 with AERONET showed 0.85 at Anmyon and 0.40 at Shirahama. The R for MODIS ranged from 0.2 to 0.96. This algorithm has relatively larger retrieval error than other multiple-channel algorithm due to the limitation in characterizing surface reflectance and aerosol property.

Kim, Mijin; Kim, Jhoon; Yoon, Jong Min

2009-03-01

134

The First of A New Generation of Meteorological Geo-stationary Satellites Ready For Launch  

NASA Astrophysics Data System (ADS)

The European Space Agency (ESA) in line with one of its mandates, to undertake demonstration of Earth Observation applications, had started back in 1977 a series of geostationary meteorological satellites Meteosat, now being operated by the European organization Eumetsat. Following the great success of such missions, ESA has co- operated with the later organization by developing a new series of satellites, designed to gather meteorological information from the same viewpoint i.e. a geo-stationery orbit. This features a dramatic increase in the number of available spectral channels: from 3 to 12, much higher resolution (1 Km in the broadband) and doubled scanning rate (from 30 min to 15 min), thanks to a newly designed sophisticated radiometer. The satellite also carries an instrument to measure the Earth Radiation Budget, useful for climate studies, and an SR transponder aimed to humanitarian purposes. Following a decision taken by Eumetsat, MSG-1 which had been stored during most of 2001, was de-stored by industry (Alcatel Space, Cannes-F), in fall 2001, in preparation for a planned launch in July 2002 from the Kourou site in French Guyana. The paper will focus on the spacecraft development programme and its status at the time of the Conference.

Oriol-Pibernat, E.; Oremus, R.

135

Synergistic Opportunities for the Geostationary Satellite Constellation: Status of the CEOS Activity  

NASA Astrophysics Data System (ADS)

This talk will summarize activities of the Committee on Earth Observation Satellites (CEOS) Atmospheric Composition Constellation (ACC) to collaboratively advance the next generation of air quality monitoring from space. Over the past 2 years, CEOS ACC have developed a position paper describing the benefits to be derived from such collaboration. The resulting ACC recommendations were endorsed by CEOS in May 2011. We will discuss next steps toward implementing this vision, starting with a new 3-year CEOS Action in 2012. Several countries and space agencies are currently planning to launch geostationary Earth orbit (GEO) missions in 2017-2022 to obtain atmospheric composition measurements for characterizing anthropogenic and natural distributions of tropospheric ozone, aerosols, and their precursors. These missions include Europe's ESA Sentinel-4 with EUMETSAT IRS, the United States' NASA GEO-CAPE, Korea's ME/MEST/KARI GEMS, and Japan's JAXA GMAP-Asia. GEO observations offer a quantum advance in air quality monitoring from space by providing measurements many times per day. However, a single GEO satellite views only a portion of the globe. These satellites, positioned to view Europe, East Asia, and North America, will collectively provide hourly coverage of the industrialized Northern Hemisphere at similar spatial resolutions. Planned low Earth orbit (LEO) missions will provide complementary daily global observations. Observations from a single LEO satellite will overlap those from each GEO satellite once per day, providing a means for combining the GEO observations and a necessary perspective for interpreting global impacts of smaller scale processes. The EUMETSAT Metop series, NOAA/NASA JPSS series, and ESA Sentinel-5 Precursor and Sentinel-5 missions will each provide such daily overlap with the GEO missions. The Canadian PCW PHEMOS mission will make an additional unique suite of observations. PCW will provide quasi-geostationary coverage over the Arctic that overlaps with each geostationary satellite over 30N - 60N, adding opportunities for intercalibration many times per day. The development of common data products, data distribution protocols, and calibration strategies will synergistically enable critically needed understanding of the interactions between regional and global atmospheric composition. Common air quality trace gas products will be tropospheric column O3, NO2, HCHO, and SO2 nominally at 8 km spatial resolution and 1 hour temporal frequency. Detection of aerosols in the UV will allow absorbing aerosols to be distinguished from total aerosol optical depth, providing information on aerosol speciation and particularly relevant to the air quality/climate interface associated with aerosol radiative forcing. Such activities directly address societal benefit areas of the Global Earth Observation System of Systems (GEOSS), including Health, Energy, Climate, Disasters, and Ecosystems, and are responsive to the requirements of each mission to provide advanced user services and societal benefits in their own regions.

Al-Saadi, J. A.; Zehner, C.

2012-12-01

136

Workshop on Satellites for Solar Energy Resource Information -Washington, DC, April 10-11, 1996 POTENTIALS OF IMAGES FROM GEOSTATIONARY SATELLITE DATA FOR THE  

E-print Network

Workshop on Satellites for Solar Energy Resource Information - Washington, DC, April 10-11, 1996 POTENTIALS OF IMAGES FROM GEOSTATIONARY SATELLITE DATA FOR THE ASSESSMENT OF SOLAR ENERGY PARAMETERS Lucien by meteorological geostationary satellites are currently used to map global radiation. Several methods exist which

Paris-Sud XI, Université de

137

Geostationary-satellite beacon-receiver array for studies of ionospheric irregularities  

SciTech Connect

Ionospheric irregularities can be studied by various techniques. These include widely spaced Doppler sounders or ionosondes, Faraday rotation polarimetry, and two-frequency differential Doppler, and radio interferometry. With geostationary satellites, one usually uses Faraday rotation of the beacon signal to measure the ionospheric TEC. With a network of polarimeters, the horizontal wave parameters of Traveling Ionospheric Disturbances (TIDS) can be deduced, but the shortcoming of this technique is its poor sensitivity. This paper describes a geostationary-satellite beacon-receiver array at Los Alamos, New Mexico, which will be employed for the studying of ionospheric irregularities, especially the fine-scale TIDS.

Carlos, R.C.; Jacobson, A.R.; Wu, Guanghui

1992-09-01

138

Geostationary-satellite beacon-receiver array for studies of ionospheric irregularities  

SciTech Connect

Ionospheric irregularities can be studied by various techniques. These include widely spaced Doppler sounders or ionosondes, Faraday rotation polarimetry, and two-frequency differential Doppler, and radio interferometry. With geostationary satellites, one usually uses Faraday rotation of the beacon signal to measure the ionospheric TEC. With a network of polarimeters, the horizontal wave parameters of Traveling Ionospheric Disturbances (TIDS) can be deduced, but the shortcoming of this technique is its poor sensitivity. This paper describes a geostationary-satellite beacon-receiver array at Los Alamos, New Mexico, which will be employed for the studying of ionospheric irregularities, especially the fine-scale TIDS.

Carlos, R.C.; Jacobson, A.R.; Wu, Guanghui.

1992-01-01

139

Measurement on simple vehicle antenna system using a geostationary satellite in Japan  

Microsoft Academic Search

This paper provided a measurement campaign of simple antenna system mounted on a vehicle by utilising a Japanese geostationary test satellite called Engineering Test Satellite VIII (ETS-VIII). We developed an antenna system that was compact, light weight, and promising in low cost production. The antenna system was built by a 16-cm patch array antenna, which had simple satellite-tracking method that

Basari; Kazuyuki Saito; Masaharu Takahashi; Koichi Ito

2010-01-01

140

Field Measurement on Simple Vehicle-Mounted Antenna System Using a Geostationary Satellite  

Microsoft Academic Search

This paper presents a field measurement of a simple antenna system mounted on a vehicle by utilizing a geostationary test satellite called Engineering Test Satellite VIII (ETS-VIII). Our developed antenna system is compact, lightweight, and promising for low-cost production. The antenna system is constructed by a 16-cm patch array antenna, which has simple satellite tracking that is controlled by a

B. Basari; K. Saito; M. Takahashi; K. Ito

2010-01-01

141

Aviation utilization of geostationary satellites for the augmentation to GPS: Ranging and data link  

NASA Astrophysics Data System (ADS)

The Wide Area Augmentation System (WAAS) is a GPS-based navigation aid currently under development by the Federal Aviation Administration (FAA). WAAS will provide corrections to aviation users for the GPS clock, its ephemeris, and for the delay in its signal as it passes through the ionosphere. These corrections will be broadcast to users throughout the United States via geostationary satellites. A master station that combines data from a continental network of reference GPS receivers will create these messages. The geostationary satellites serve both as wide-area differential GPS data links as well as additional ranging sources. The data message stream of WAAS enhances the accuracy and integrity of the GPS signal for aviation. Simultaneously, the satellite ranging-source increases the percentage of time that the precise signal is available. In this way, WAAS provides needed improvements in four metrics over the standard GPS signal: accuracy, integrity, availability, and continuity. The ranging function, described above, requires an estimate of the position of the geostationary satellite. This dissertation presents a novel technique for generating this position estimate. This technique is designed to provide high integrity performance in the user position domain and operates in real-time. As such, it contrasts classical orbit determination techniques that have no integrity requirement, are not designed to optimize performance in the user position domain, and usually have no real-time requirement. Our estimator is evaluated using real data from the FAA's National Satellite Test Bed (NSTB). The WAAS Signal-In-Space (SIS) has a limited data message bandwidth of 250 bits-per-second. This data bandwidth was chosen to balance two concerns. First, the power of the signal must not be so strong that it jams GPS. Second, the signal must provide the minimum amount of information necessary to ensure adequate accuracy and integrity for aviation users over the entire poststationary satellite footprint. The required message loss rate is specified not to exceed a rate of 0.001 (one loss per one-thousand messages) to ensure adequate system continuity and availability. The WAAS message structure is not particularly sensitive to independent message losses below the specified rate. Groups of missed messages (burst-mode) can prove to be a challenge in maintaining a continuous WAAS solution. The effects of burst-mode losses on the quality of the WAAS solution is presented and a Markov model for the burst message loss is developed. This research shows that these burst message losses can be tolerated for WAAS availability provided that the message loss rate does not exceed a rate of 0.005. Flight tests were conducted in California and Alaska to establish actual message loss profiles for aircraft. These flight test results were modeled and used in conjunction with NSTB reference station data to establish availability of WAAS solutions for various locations in the US.

Fuller, Richard Andrew, II

2000-08-01

142

Imaging Geostationary Satellites with a Common-Mount Interferometer: Image Quality and Fringe Tracking  

NASA Astrophysics Data System (ADS)

Imaging geostationary satellites is difficult because they are both too large and too small. They are too small to resolve with existing ground-based single telescopes, and they are too large (and too faint) to resolve with existing ground-based interferometers. Earth-rotation synthesis also does not work with geostationary satellites. We have designed a common-mount telescopes which we believe is the right instrument for geostationary satellite imaging, and described it previously in a number of publications (e.g. AMOS papers Mozurkewich et al. 2011, Jorgensen et al. 2011, Schmitt et al. 2011, and others). In this paper we will provide an overview of the instrument and explore its capabilities in more detail, using a typical geostationary satellite as an example. Specifically we will look at the fringe-tracking capability which is required for phase measurement and thus imaging. We will also look at the required integration time and its relationship to fringe-tracking capability and image quality.

Jorgensen, A.; Schmitt, H.; Mozurkewich, D.; Armstrong, J. T.; Hindsley, R. B.; Baines, E. K.

2012-09-01

143

Geostationary satellite positioning by DLR/GSOC operations and management methods  

NASA Technical Reports Server (NTRS)

Starting with a short description of the GSOC (German Space Operations Center) and its role within the wider framework of the research institute DLR, this paper provides a review of the geostationary telecommunications satellites positioned by the GSOC. The paper then proceeds to describe the evolution of the operations and management structures and methods which have been effectively used to accomplish these missions.

Brittinger, Peter

1994-01-01

144

Use of hourly Geostationary Operational Environmental Satellite (GOES) fire emissions in a Community Multiscale Air Quality  

E-print Network

the Sparse Matrix Operator Kernel Emissions (SMOKE) model. The impacts of fire emissions are obtainedUse of hourly Geostationary Operational Environmental Satellite (GOES) fire emissions that originated in Georgia and Florida during the April­May 2007 period. In order to quantify the impacts

Christopher, Sundar A.

145

Flight Trials of a Geostationary Satellite Based Augmentation System at High  

E-print Network

Flight Trials of a Geostationary Satellite Based Augmentation System at High Latitudes and for Dual flight demonstrations have taken place over the past few years to show how the Wide-Area Augmentation, flight tests were carried out to further show the possibilities of such a system to aviation. Some

Stanford University

146

Improved Finite Impulse Response Filters for Enhanced Destriping of Geostationary Satellite Data  

Microsoft Academic Search

The visible infrared spin scan radiometer (VISSR) common to many geostationary satellites produces visible wavelength data contaminated with stripes. The stripes affect the usefulness of the data in quantitative studies. This paper briefly reviews the cause of the striping and then develops a tapered window finite impulse response (FIR) filter and a constrained least squares FIR filter. Both filters minimize

James J. Simpson; James R. Stitt; David M. Leath

1998-01-01

147

A star scan\\/attitude determination experiment conducted on the Geostationary Meteorological Satellite  

Microsoft Academic Search

The paper discusses the results of a star scan test performed on the spin stabilized Geostationary Meteorological Satellite (GMS) and used for the purpose of determining the vehicle's spin state. The test data shows that the payload camera, normally used for imaging the earth and its cloud cover, sees a sufficient number of stars to provide for a rapid and

J. E. McIntyre; S. C. Jennings; R. C. Cox

1978-01-01

148

Analysing the Advantages of High Temporal Resolution Geostationary MSG SEVIRI Data Compared to Polar Operational Environmental Satellite Data for Land Surface Monitoring in Africa  

NASA Technical Reports Server (NTRS)

Since 1972, satellite remote sensing of the environment has been dominated by polar-orbiting sensors providing useful data for monitoring the earth s natural resources. However their observation and monitoring capacity are inhibited by daily to monthly looks for any given ground surface which often is obscured by frequent and persistent cloud cover creating large gaps in time series measurements. The launch of the Meteosat Second Generation (MSG) satellite into geostationary orbit has opened new opportunities for land surface monitoring. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) instrument on-board MSG with an imaging capability every 15 minutes which is substantially greater than any temporal resolution that can be obtained from existing polar operational environmental satellites (POES) systems currently in use for environmental monitoring. Different areas of the African continent were affected by droughts and floods in 2008 caused by periods of abnormally low and high rainfall, respectively. Based on the effectiveness of monitoring these events from Earth Observation (EO) data the current analyses show that the new generation of geostationary remote sensing data can provide higher temporal resolution cloud-free (less than 5 days) measurements of the environment as compared to existing POES systems. SEVIRI MSG 5-day continental scale composites will enable rapid assessment of environmental conditions and improved early warning of disasters for the African continent such as flooding or droughts. The high temporal resolution geostationary data will complement existing higher spatial resolution polar-orbiting satellite data for various dynamic environmental and natural resource applications of terrestrial ecosystems.

Fensholt, R.; Anyamba, A.; Huber, S.; Proud, S. R.; Tucker, C. J.; Small, J.; Pak, E.; Rasmussen, M. O.; Sandholt, I.; Shisanya, C.

2011-01-01

149

Feasibility study for Japanese Air Quality Mission from Geostationary Satellite: Infrared Imaging Spectrometer  

NASA Astrophysics Data System (ADS)

A Geostationary Earth Orbit (GEO) satellite is potentially able to monitor the regional distribution of pollution with good spatial and temporal resolution. The Japan Society of Atmospheric Chemistry (JSAC) and the Japanese Space Exploration Agency (JAXA) initiated a concept study for air quality measurements from a GEO satellite targeting the Asian region [1]. This work presents the results of sensitivity studies for a Thermal Infrared (TIR) (650-2300cm-1) candidate instrument. We performed a simulation study and error analysis to optimize the instrumental operating frequencies and spectral resolution. The scientific requirements, in terms of minimum precision (or error) values, are 10% for tropospheric O3 and CO and total column of HN3 and nighttime HNO2 and 25% for O3 and CO with separating 2 or 3 column in troposphere. Two atmospheric scenarios, one is Asian background, second is polluted case, were assumed for this study. The forward calculations and the retrieval error analysis were performed with the AMATERASU model [2] developed within the NICT-THz remote sensing project. Retrieval error analysis employed the Optimal Estimation Method [3]. The geometry is off-nadir observation on Tokyo from the geostationary satellite at equator. Fine spectral resolution will allow to observe boundary layer O3 and CO. We estimate the observation precision in the spectral resolution from 0.1cm-1 to 1cm-1 for 0-2km, 2-6km, and 6-12km. A spectral resolution of 0.3 cm-1 gives good sensitivity for all target molecules (e.g. tropospheric O3 can be detected separated 2 column with error 30%). A resolution of 0.6 cm-1 is sufficient to detect tropospheric column amount of O3 and CO (in the Asian background scenario), which is within the required precision and with acceptable instrumental SNR values of 100 for O3 and 30 for CO. However, with this resolution, the boundary layer ozone will be difficult to detect in the background abundance. In addition, a spectral resolution of 0.6 cm-1 is sufficient to retrieve the total column of HNO3 and NO2 with a precision better than 10%. IR measurements will thus be useful for tropospheric pollution monitoring. Reference: [1] http://www.stelab.nagoya-u.ac.jp/ste-www1/div1/taikiken/eisei/eisei2.pdf, Japanese version only [2] P. Baron et al., AMATERASU: Model for Atmospheric TeraHertz Radiation Analysis and Simulation, Journal of the National Institute of Information and Communications Technology, 55(1), 109-121, 2008. [3] Rodgers. C. D., Inverse methods for atmospheric sounding: Theory and practice, World Scientific, Singapore (2000).

Sagi, K.; Kasai, Y.; Philippe, B.; Suzuki, K.; Kita, K.; Hayashida, S.; Imasu, R.; Akimoto, H.

2009-12-01

150

Comparison of Cloud Properties from CALIPSO-CloudSat and Geostationary Satellite Data  

NASA Technical Reports Server (NTRS)

Cloud properties are being derived in near-real time from geostationary satellite imager data for a variety of weather and climate applications and research. Assessment of the uncertainties in each of the derived cloud parameters is essential for confident use of the products. Determination of cloud amount, cloud top height, and cloud layering is especially important for using these real -time products for applications such as aircraft icing condition diagnosis and numerical weather prediction model assimilation. Furthermore, the distribution of clouds as a function of altitude has become a central component of efforts to evaluate climate model cloud simulations. Validation of those parameters has been difficult except over limited areas where ground-based active sensors, such as cloud radars or lidars, have been available on a regular basis. Retrievals of cloud properties are sensitive to the surface background, time of day, and the clouds themselves. Thus, it is essential to assess the geostationary satellite retrievals over a variety of locations. The availability of cloud radar data from CloudSat and lidar data from CALIPSO make it possible to perform those assessments over each geostationary domain at 0130 and 1330 LT. In this paper, CloudSat and CALIPSO data are matched with contemporaneous Geostationary Operational Environmental Satellite (GOES), Multi-functional Transport Satellite (MTSAT), and Meteosat-8 data. Unlike comparisons with cloud products derived from A-Train imagers, this study considers comparisons of nadir active sensor data with off-nadir retrievals. These matched data are used to determine the uncertainties in cloud-top heights and cloud amounts derived from the geostationary satellite data using the Clouds and the Earth s Radiant Energy System (CERES) cloud retrieval algorithms. The CERES multi-layer cloud detection method is also evaluated to determine its accuracy and limitations in the off-nadir mode. The results will be useful for constraining the use of the passive retrieval data in models and for improving the accuracy of the retrievals.

Nguyen, L.; Minnis, P.; Chang, F.; Winker, D.; Sun-Mack, S.; Spangenberg, D.; Austin, R.

2007-01-01

151

Digital meteorological radar data compared with digital infrared data from a geostationary meteorological satellite  

E-print Network

DIGITAL METEOROLOGICAL RADAR DATA COMPARED WITH DIGITAL INFRARED DATA FROM A GEOSTATIONARY METEOROLOGICAL SATELLITE A Thesis by RODNEY STUART HENDFRSON Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIFNCE May I979 Ma jor Subject: Meteorology DIGITAL METEOROLOGICAL RADAR DATA COMPARED WITH DIGITAL INFRARED DATA FROM A GEOSTATIONAFY METEOROLOGICAL SATELLITE A Thesis by RODNEY STUART HENDERSON Approved...

Henderson, Rodney Stuart

1979-01-01

152

On the use of satellites in Molniya orbit for meteorological and oceanographic observations of the high latitudes  

NASA Technical Reports Server (NTRS)

Two types of orbits are currently used for meteorological satellites: geostationary orbit and low earth orbit. Neither orbit serves the high latitudes well. The Soviet Molniya satellites fly in a highly elliptic orbit inclined 63.4 deg to the equator. For approximately 8 h of its 12-h orbit, a satellite in Molniya orbit is synchronized with the earth such that it is nearly geostationary in the high latitudes. A meteorological/oceanographic satellite in Molniya orbit would bring nearly the same frequent imaging capability to the high latitudes which the tropics and mid-latitudes now enjoy. The uses of such a satellite include Arctic forecasting, study of polar lows, high latitude precipitation estimation, Antarctic studies, sea ice monitoring, and ozone measurements.

Kidder, Stanley Q.

1992-01-01

153

Precise orbit determination of Beidou Satellites at GFZ  

NASA Astrophysics Data System (ADS)

In December 2012 the Signal-In-Space Interface Control Document (ICD) of the BeiDou Navigation Satellite System (BeiDou system) was published. Currently the initial BeiDou regional navigation satellite system consisting of 14 satellites was completed, and provides observation data of five Geostationary-Earth-Orbit (GEO)satellites, five Inclined-GeoSynchronous-Orbit (IGSO) satellites and four Medium-Earth-Orbit (MEO) satellites. The Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences (GFZ) contributes as one of the analysis centers to the International GNSS Service (IGS) since many years. In 2012 the IGS began the "Multi GNSS EXperiment" (MGEX), which supports the new GNSS, such as Galileo, Compass, and QZSS. Based on tracking data of BeiDou-capable receivers from the MGEX and chinese BeiDou networks up to 45 global distributed stations are selected to estimate orbit and clock parameters of the GPS/BeiDou satellites. Some selected results from the combined GPS/BeiDou data processing with 10 weeks of data from 2013 are shown. The quality of the orbit and clock products are assessed by means of orbit overlap statistics, clock stabilities as well as an independent validation with SLR measurements. At the end an outlook about GFZ AC's future Multi-GNSS activities will be given.

Deng, Zhiguo; Ge, Maorong; Uhlemann, Maik; Zhao, Qile

2014-05-01

154

Ozone air quality measurement requirements for a geostationary satellite mission Peter Zoogman a,*, Daniel J. Jacob a,b  

E-print Network

Ozone air quality measurement requirements for a geostationary satellite mission Peter Zoogman a Accepted 23 May 2011 Keywords: Air quality Ozone Kalman filter Assimilation Remote sensing a b s t r a c-CAPE geostationary air quality mission over North America. We consider instruments using different spec- tral

Chance, Kelly

155

The Study and Applications of Satellite and Satellite Constellation Autonomous Orbit Determination Using Star Sensor  

NASA Astrophysics Data System (ADS)

Autonomous satellite orbit determination is a key technique in autonomous satellite navigation. Many kinds of technologies have been proposed to realize the autonomous satellite navigation, such as the star sensor, the Earth magnetometer, the occultation time survey, and the phase measurement of X-ray pulsar signals. This dissertation studies a method of autonomous satellite orbit determination using star sensor. Moreover, the method is extended to the autonomous navigation of satellite constellation and the space-based surveillance. In chapters 1 and 2, some usual time and reference systems are introduced. Then the principles of several typical autonomous navigation methods, and their merits and shortcomings are analyzed. In chapter 3, the autonomous satellite orbit determination using star sensor and infrared Earth sensor (IRES) is specifically studied, which is based on the status movement simulation, the stellar background observation from star sensor, and the Earth center direction survey from IRES. By simulating the low Earth orbit satellites and pseudo Geostationary Earth orbit (PGEO) satellites, the precision of position and speed with autonomous orbit determination using star sensor is obtained. Besides, the autonomous orbit determination using star sensor with double detectors is studied. According to the observation equation's characters, an optimized type of star sensor and IRES initial assembly model is proposed. In the study of the PGEO autonomous orbit determination, an efficient sampling frequency of measurements is promoted. The simulation results confirm that the autonomous satellite orbit determination using star sensor is feasible for satellites with all kinds of altitudes. In chapter 4, the method of autonomous satellite orbit determination using star sensor is extended to the autonomous navigation of mini-satellite constellation. Combining with the high-accuracy inter satellite links data, the precision of the determined orbit and constellation configuration is higher than that ever expected. In chapter 5, two related pre-project researches are developed with respect to the space-based satellite surveillance. One solves the un-convergence question in the preliminary orbit determination and finds an advantageous preliminary orbit determination using inter satellite angle measurement. In the other pre-project research, a creative space-based satellite surveillance model is proposed, which is based on the autonomous surveillance platform navigation. Using the star sensor's navigation data associated with the inter satellite angle measurement, the orbit parameters of the tracking space objects and the surveillance platform are determined. Compared to the available experiment results overseas, the preliminary orbit determination method and the autonomous navigation surveillance platform model are found to be feasible. The research will significantly contribute to the new conception of ``space awareness'', as well as our country's space security construction.

Gan, Q. B.

2012-07-01

156

The science benefits of and the antenna requirements for microwave remote sensing from geostationary orbit  

NASA Technical Reports Server (NTRS)

The primary objective of the Large Space Antenna (LSA) Science Panel was to evaluate the science benefits that can be realized with a 25-meter class antenna in a microwave/millimeter wave remote sensing system in geostationary orbit. The panel concluded that a 25-meter or larger antenna in geostationary orbit can serve significant passive remote sensing needs in the 10 to 60 GHz frequency range, including measurements of precipitation, water vapor, atmospheric temperature profile, ocean surface wind speed, oceanic cloud liquid water content, and snow cover. In addition, cloud base height, atmospheric wind profile, and ocean currents can potentially be measured using active sensors with the 25-meter antenna. Other environmental parameters, particularly those that do not require high temporal resolution, are better served by low Earth orbit based sensors.

Stutzman, Warren L. (editor); Brown, Gary S. (editor)

1991-01-01

157

Low Earth orbit communications satellite  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

158

Monitoring high-ozone events in the US Intermountain West using TEMPO geostationary satellite observations  

NASA Astrophysics Data System (ADS)

High-ozone events, approaching or exceeding the National Ambient Air Quality Standard (NAAQS), are frequently observed in the US Intermountain West in association with subsiding air from the free troposphere. Monitoring and attribution of these events is problematic because of the sparsity of the current network of surface measurements and lack of vertical information. We present an Observing System Simulation Experiment (OSSE) to evaluate the ability of the future geostationary satellite instrument Tropospheric Emissions: Monitoring of Pollution (TEMPO), scheduled for launch in 2018-2019, to monitor and attribute high-ozone events in the Intermountain West through data assimilation. TEMPO will observe ozone in the ultraviolet (UV) and visible (Vis) bands to provide sensitivity in the lower troposphere. Our OSSE uses ozone data from the GFDL AM3 chemistry-climate model (CCM) as the "true" atmosphere and samples it for April-June 2010 with the current surface network (CASTNet -Clean Air Status and Trends Network- sites), a configuration designed to represent TEMPO, and a low Earth orbit (LEO) IR (infrared) satellite instrument. These synthetic data are then assimilated into the GEOS-Chem chemical transport model (CTM) using a Kalman filter. Error correlation length scales (500 km in horizontal, 1.7 km in vertical) extend the range of influence of observations. We show that assimilation of surface data alone does not adequately detect high-ozone events in the Intermountain West. Assimilation of TEMPO data greatly improves the monitoring capability, with little information added from the LEO instrument. The vertical information from TEMPO further enables the attribution of NAAQS exceedances to background ozone. This is illustrated with the case of a stratospheric intrusion.

Zoogman, P.; Jacob, D. J.; Chance, K.; Liu, X.; Lin, M.; Fiore, A.; Travis, K.

2014-06-01

159

Assessment of net primary productivity over India using Indian geostationary satellite (INSAT-3A) data  

NASA Astrophysics Data System (ADS)

Polar orbiting satellites (MODIS and SPOT) have been commonly used to measure terrestrial Net Primary Productivity (NPP) at regional/global scale. Charge Coupled Device (CCD) instrument on geostationary INSAT-3A platform provides a unique opportunity for continuous monitoring of ecosystem pattern and process study. An improved Carnegie-Ames-Stanford Approach (iCASA) model is one of the most expedient and precise ecosystem models to estimate terrestrial NPP. In this paper, an assessment of terrestrial NPP over India was carried out using the iCASA ecosystem model based on the INSAT CCD derived Normalized Difference Vegetation Index (NDVI) with multisource meteorological data for the year 2009. NPP estimated from the INSAT CCD followed the characteristic growth profile of most of the vegetation types in the country. NPP attained maximum during August and September, while minimum in April. Annual NPP for different vegetation types varied from 1104.55 gC m-2 year-1 (evergreen broadleaf forest) to 231.9 gC m-2 year-1 (grassland) with an average NPP of 590 gC m-2 year-1. We estimated 1.9 PgC of net carbon fixation over Indian landmass in 2009. Biome level comparison between INSAT derived NPP and MODIS NPP indicated a good agreement with the Willmott's index of agreement (d) ranging from 0.61 (Mixed forest) to 0.99 (Open Shrubland). Our findings are consistent with the earlier NPP studies in India and indicate that INSAT derived NPP has the capability to detect spatial and temporal variability of terrestrial NPP over a wide range of terrestrial ecosystems in India. Thus INSAT-3A data can be used as one of the potential satellite data source for accurate biome level carbon estimation in India.

Goroshi, S. K.; Singh, R. P.; Pradhan, R.; Parihar, J. S.

2014-11-01

160

On-orbit control of the Communications Technology Satellite (CTS)/HERMES  

NASA Technical Reports Server (NTRS)

A variety of control functions for the CIS HERMES satellite are reviewed. Its mission, to demonstrate high power SHF (12 GHz) transmission is discussed. The satellite was controlled in geostationary orbit for nearly four years from the satellite control center in Ottawa, Canada. Highlights of these operations are outlined. The interactions between many of the automatic onboard control functions and control from the ground are described. Special emphasis is placed on the characteristics and performance of the three axis attitude control system.

Raine, H. R.

1980-01-01

161

EHL Transition Temperature Measurements on a Geostationary Operational Environmental Satellite (GOES) Filter Wheel Bearing  

NASA Technical Reports Server (NTRS)

The elastohydrodynamic lubrication (EHL) transition temperature was measured for a Geostationary Operational Environmental Satellite (GOES) sounder filter wheel bearing in a vacuum tribometer. Conditions included both an 89 N (20 lb.) hard and soft load, 600 rpm, temperatures between 23 C (73 F) and 85 C (185 F), and a vacuum of approximately 1.3 x 10(exp -5) Pa. Elastohydrodynamic to mixed lubrication started to occur at approximately 70 C (158 F).

Jansen, Mark J.; Jones, William R., Jr.; Pepper, Stephen V.; Predmore, Roamer E.; Shogrin, Bradley A.

2001-01-01

162

Investigation of mesoscale meteorological phenomena as observed by geostationary satellite  

NASA Technical Reports Server (NTRS)

Satellite imagery plus conventional synoptic observations were used to examine three mesoscale systems recently observed by the GOES-EAST satellite. The three systems are an arc cloud complex (ACC), mountain lee wave clouds and cloud streets parallel to the wind shear. Possible gravity-wave activity is apparent in all three cases. Of particular interest is the ACC because of its ability to interact with other mesoscale phenomena to produce or enhance convection.

Brundidge, K. C.

1982-01-01

163

Near-real-time global biomass burning emissions product from geostationary satellite constellation  

NASA Astrophysics Data System (ADS)

Near-real-time estimates of biomass burning emissions are crucial for air quality monitoring and forecasting. We present here the first near-real-time global biomass burning emission product from geostationary satellites (GBBEP-Geo) produced from satellite-derived fire radiative power (FRP) for individual fire pixels. Specifically, the FRP is retrieved using WF_ABBA V65 (wildfire automated biomass burning algorithm) from a network of multiple geostationary satellites. The network consists of two Geostationary Operational Environmental Satellites (GOES) which are operated by the National Oceanic and Atmospheric Administration, the Meteosat second-generation satellites (Meteosat-09) operated by the European Organisation for the Exploitation of Meteorological Satellites, and the Multifunctional Transport Satellite (MTSAT) operated by the Japan Meteorological Agency. These satellites observe wildfires at an interval of 15-30 min. Because of the impacts from sensor saturation, cloud cover, and background surface, the FRP values are generally not continuously observed. The missing observations are simulated by combining the available instantaneous FRP observations within a day and a set of representative climatological diurnal patterns of FRP for various ecosystems. Finally, the simulated diurnal variation in FRP is applied to quantify biomass combustion and emissions in individual fire pixels with a latency of 1 day. By analyzing global patterns in hourly biomass burning emissions in 2010, we find that peak fire season varied greatly and that annual wildfires burned 1.33 × 1012 kg dry mass, released 1.27 × 1010 kg of PM2.5 (particulate mass for particles with diameter <2.5 ?m) and 1.18 × 1011kg of CO globally (excluding most parts of boreal Asia, the Middle East, and India because of no coverage from geostationary satellites). The biomass burning emissions were mostly released from forest and savanna fires in Africa, South America, and North America. Evaluation of emission result reveals that the GBBEP-Geo estimates are comparable with other FRP-derived estimates in Africa, while the results are generally smaller than most of the other global products that were derived from burned area and fuel loading. However, the daily emissions estimated from GOES FRP over the United States are generally consistent with those modeled from GOES burned area and MODIS (Moderate Resolution Imaging Spectroradiometer) fuel loading, which produces an overall bias of 5.7% and a correlation slope of 0.97 ± 0.2. It is expected that near-real-time hourly emissions from GBBEP-Geo could provide a crucial component for atmospheric and chemical transport modelers to forecast air quality and weather conditions.

Zhang, Xiaoyang; Kondragunta, Shobha; Ram, Jessica; Schmidt, Christopher; Huang, Ho-Chun

2012-07-01

164

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

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

165

Power conditioning units for high power geostationary satellites  

Microsoft Academic Search

To be competitive on the telecommunication commercial satellites market, the components of the electrical power subsystem (EPS) have to be more and more easily adaptable to the output power level and to the payloads specific characteristics. The design driving factors are not only that required modularity and adaptability, but also the electrical and mechanical performances and the manufacturing costs. The

J. P. Castiaux; P. Bury; B. Liegeois

1997-01-01

166

Satellite physical and orbital characteristics  

NASA Technical Reports Server (NTRS)

Perhaps sixty satellites received sufficient tracking to warrant their consideration for inclusion in the current gravity field development activities underway for TOPEX. These objects vary in size, shape, and in their orbital history -- and in the information available concerning any and all of these characteristics. An attempt to obtain initial information on the satellite physical characteristics and the overall size of nongravitational perturbations for each of the satellites under consideration. Atmospheric drag perturbations were modeled and a solution for zonal harmonics was made. Calibrated area-to-mass ratios and estimates of nonconservative force accelerations are tabulated.

Klosko, S. M.

1985-01-01

167

Detection of a geostationary satellite with the Navy Prototype Optical Interferometer  

NASA Astrophysics Data System (ADS)

We have detected a satellite via optical interferometry for the first time, using a 16 m baseline of the Navy Prototype Optical Interferometer (NPOI) to observe the geostationary communications satellite DirecTV-9S during the "glint" seasons of February-March 2008 and 2009 when the sun-satellite-NPOI geometry was favorable for causing specular reflections from geostationary satellites. We used the US Naval Observatory Flagstaff Station 1 m telescope to generate accurate positions for steering the NPOI. Stars are the easiest targets for optical/infrared interferometers because of their high surface brightness. Low surface brightness targets are more difficult: if they are small enough not to be resolved out by typical baselines, they are likely to be too faint to produce detectable fringes in an atmospheric coherence time. The 16 m NPOI baseline, the shortest available at the time of our observations, resolves out structures larger than ~ 1.5 m at the geostationary distance, while a typical size for the solar panel arrays is 2 m x 30 m. Our detection indicates that a small fraction of the satellite glinted, not surprising given that the solar panels are not accurately flat. Our fringe data are consistent with a two-component image consisting of a 1 to 1.3 m higher surface brightness component and a significantly larger lower surface brightness component. The brightness of the glints (2.m 4 and ~ 1.m 5 for the two detections in March 2009) and the size scale suggest that the compact component has an albedo of 0.06 to 0.13, while the larger-scale component is much darker, if circular geometry is assumed.

Armstrong, J. T.; Hindsley, R. B.; Schmitt, H. R.; Vrba, F. J.; Benson, J. A.; Hutter, D. J.; Zavala, R. T.

2010-07-01

168

Convective and stratiform cloud rainfall estimation from geostationary satellite data  

NASA Astrophysics Data System (ADS)

The Bayes Decision (BD) method was used to distinguish the convective and stratiform components of cloud systems from GMS-4 satellite data. A technique originally developed by Adler and Negri (1988, hereafter abbreviated AN) was improved for estimating the convective and stratiform cloud precipitation areas and rates of cloud systems from GMS satellite imagery. It has been applied to a tropical cyclonic cloud cluster observed over east coast area of China on September 23, 1992, which brought about flood disaster in that region. Overlaid 6-hour surface rainfall observations show that the rainfall areas and amounts match with results from improved AN technique. The successful application of the Adler and Negri's technique to convective and stratiform clouds provides encouragement for the use of this method over large region of mid-latitude China where radar data are not fully covered.

Li, Jun; Wang, Luyi; Zhou, Fengxian

1993-12-01

169

Low Bus Voltage Hydrazine Arcjet System for Geostationary Satellites  

NASA Astrophysics Data System (ADS)

The capabilities of arcjet propulsion systems were recently extended to accommodate operation on the NASDA Data Relay Test Satellite (DRTS) providing a power bus voltage between 31 and 51.5 VDC. This paper summarizes the newly attained qualification status of the MR 512 arcjet system demonstrating the flexibility of the current design. A redesign of the Power Processing Unit (PPU) became necessary as well as a delta-qualification of the thruster to validate spacecraft integration and to provide compliance with the DRTS satellite environmental requirements. Two types of thrusters with different thrust levels were made available to meet mission requirements. The delta-qualification included a pyro-shock test, vibration tests to a higher level than previously tested, and performance mapping beyond the original range. Included in the paper is an assessment of the PPU performance characteristics as well as the discussion of the system operation and system telemetry.

Zube, Dieter M.; Fye, Dan

1998-07-01

170

Lightning data study in conjunction with geostationary satellite data  

NASA Technical Reports Server (NTRS)

During the summer of 1985, cloud-to-ground stroke lightning were collected. Thirty minute samples of lightning were compared with GOES IR fractional cold cloud coverage computed for three temperature thresholds (213, 243, and 273 K) twice daily (morning and evening). It was found that satellite measurements of cold cloud have a relationship to the flashrate and, in a more limited way, to the polarity and numbers of return strokes. Results varied little by location. Lightning, especially positive strokes, was found to be correlated with fractional cloud coverage, especially for clouds at or below 213 K. Other data and correlations are discussed.

Auvine, Brian; Martin, David W.

1987-01-01

171

Evaluation on penetration rate of cloud for incoming solar radiation using geostationary satellite data  

NASA Astrophysics Data System (ADS)

Solar surface insolation (SSI) represents how much solar radiance reaches the Earth's surface in a specified area and is an important parameter in various fields such as surface energy research, meteorology, and climate change. This study calculates insolation using Multi-functional Transport Satellite (MTSAT-1R) data with a simplified cloud factor over Northeast Asia. For SSI retrieval from the geostationary satellite data, the physical model of Kawamura is modified to improve insolation estimation by considering various atmospheric constituents, such as Rayleigh scattering, water vapor, ozone, aerosols, and clouds. For more accurate atmospheric parameterization, satellite-based atmospheric constituents are used instead of constant values when estimating insolation. Cloud effects are a key problem in insolation estimation because of their complicated optical characteristics and high temporal and spatial variation. The accuracy of insolation data from satellites depends on how well cloud attenuation as a function of geostationary channels and angle can be inferred. This study uses a simplified cloud factor that depends on the reflectance and solar zenith angle. Empirical criteria to select reference data for fitting to the ground station data are applied to suggest simplified cloud factor methods. Insolation estimated using the cloud factor is compared with results of the unmodified physical model and with observations by ground-based pyranometers located in the Korean peninsula. The modified model results show far better agreement with ground truth data compared to estimates using the conventional method under overcast conditions.

Yeom, Jong-Min; Han, Kyung-Soo; Kim, Jae-Jin

2012-05-01

172

G-C Orbiting Satellite  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: A satellite orbiting the earth in a circular path stays at a constant altitude of 100 kilometers throughout its orbit. Given that the radius of the ear...

2013-10-14

173

Precise Orbit Determination of BeiDou Navigation Satellite System  

NASA Astrophysics Data System (ADS)

China has been developing its own independent satellite navigation system since decades. Now the COMPASS system, also known as BeiDou, is emerging and gaining more and more interest and attention in the worldwide GNSS communities. The current regional BeiDou system is ready for its operational service around the end of 2012 with a constellation including five Geostationary Earth Orbit satellites (GEO), five Inclined Geosynchronous Orbit satellites (IGSO) and four Medium Earth orbit (MEO) satellites in operation. Besides the open service with positioning accuracy of around 10m which is free to civilian users, both precise relative positioning, and precise point positioning are demonstrated as well. In order to enhance the BeiDou precise positioning service, Precise Orbit Determination (POD) which is essential of any satellite navigation system has been investigated and studied thoroughly. To further improving the orbits of different types of satellites, we study the impact of network coverage on POD data products by comparing results from tracking networks over the Chinese territory, Asian-Pacific, Asian and of global scale. Furthermore, we concentrate on the improvement of involving MEOs on the orbit quality of GEOs and IGSOs. POD with and without MEOs are undertaken and results are analyzed. Finally, integer ambiguity resolution which brings highly improvement on orbits and positions with GPS data is also carried out and its effect on POD data products is assessed and discussed in detail. Seven weeks of BeiDou data from a ground tracking network, deployed by Wuhan University is employed in this study. The test constellation includes four GEO, five IGSO and two MEO satellites in operation. The three-day solution approach is employed to enhance its strength due to the limited coverage of the tracking network and the small movement of most of the satellites. A number of tracking scenarios and processing schemas are identified and processed and overlapping orbit differences are utilized to qualify the estimated orbits and clocks. 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. For the current tracking network, deploying tracking stations on the eastern side, for example in New Zealand and/or in Hawaii, will significantly reduce along-track biases of GEOs on the same side. The involvement of MEOs and ambiguity-fixing also make the orbits better but rather moderate. Key words: BeiDou, precise orbit determination (POD), tracking network, ambiguity-fixing

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

2013-04-01

174

Upper-Tropospheric Winds Derived from Geostationary Satellite Water Vapor Observations  

NASA Technical Reports Server (NTRS)

The coverage and quality of remotely sensed upper-tropospheric moisture parameters have improved considerably with the deployment of a new generation of operational geostationary meteorological satellites: GOES-8/9 and GMS-5. The GOES-8/9 water vapor imaging capabilities have increased as a result of improved radiometric sensitivity and higher spatial resolution. The addition of a water vapor sensing channel on the latest GMS permits nearly global viewing of upper-tropospheric water vapor (when joined with GOES and Meteosat) and enhances the commonality of geostationary meteorological satellite observing capabilities. Upper-tropospheric motions derived from sequential water vapor imagery provided by these satellites can be objectively extracted by automated techniques. Wind fields can be deduced in both cloudy and cloud-free environments. In addition to the spatially coherent nature of these vector fields, the GOES-8/9 multispectral water vapor sensing capabilities allow for determination of wind fields over multiple tropospheric layers in cloud-free environments. This article provides an update on the latest efforts to extract water vapor motion displacements over meteorological scales ranging from subsynoptic to global. The potential applications of these data to impact operations, numerical assimilation and prediction, and research studies are discussed.

Velden, Christopher S.; Hayden, Christopher M.; Nieman, Steven J.; Menzel, W. Paul; Wanzong, Steven; Goerss, James S.

1997-01-01

175

Orbital evolution. [of large natural satellite  

NASA Technical Reports Server (NTRS)

The orbital evolution of a large satellite is governed primarily by tidal interactions between the satellite and the planet it orbits. Tides raised on a planet by a satellite transfer energy and angular momentum to the satellite orbit; this changes the semimajor axes of satellite orbits, increasing the size of those orbits where the satellite mean motion is smaller than the planetary angular velocity, and decreasing those where the opposite is true. Substantial changes caused by such tides for satellites of the terrestrial planets may explain the absence of satellites about Mercury and Venus. For Jovian and Saturnian satellites, such tides probably are only important in bringing about some of the observed orbital resonances. Tides raised on satellites generally cause decreasing orbital eccentricities, indicating why close satellites always have nearly circular orbits. Different processes of orbital evolution dominate for small bodies; their effects probably are critical in positioning material in the primordial dust cloud so that satellite coagulation may occur. A qualitative description is given of the orbital results of gas drag, radiation pressure, Poynting-Robertson drag and electromagnetic forces.

Burns, J. A.

1977-01-01

176

Spectrum and orbit conservation as a factor in future mobile satellite system design  

NASA Technical Reports Server (NTRS)

Access to the radio spectrum and geostationary orbit is essential to current and future mobile satellite systems. This access is difficult to obtain for current systems, and may be even more so for larger future systems. In this environment, satellite systems that minimize the amount of spectrum orbit resource required to meet a specific traffic requirement are essential. Several spectrum conservation techniques are discussed, some of which are complementary to designing the system at minimum cost. All may need to be implemented to the limits of technological feasibility if network growth is not to be constrained because of the lack of available spectrum-orbit resource.

Bowen, Robert R.

1990-01-01

177

The Geostationary Lightning Mapper (GLM) for the GOES-R Series Next Generation Operational Environmental Satellite Constellation  

NASA Technical Reports Server (NTRS)

The next generation Geostationary Operational Environmental Satellite (GOES-R) series with a planned launch in 2015 is a follow on to the existing GOES system currently operating over the Western Hemisphere. The system will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency. The system provides products including lightning, cloud properties, rainfall rate, volcanic ash, air quality, hurricane intensity, and fire/hot spot characterization. Advancements over current GOES include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), and improved spectral, spatial, and temporal resolution for the 16-channel Advanced Baseline Imager (ABI). The Geostationary Lightning Mapper (GLM), an optical transient detector will map total (in-cloud and cloud-to-ground) lightning flashes continuously day and night with near-uniform spatial resolution of 8 km with a product refresh rate of less than 20 sec over the Americas and adjacent oceanic regions, from the west coast of Africa (GOES-E) to New Zealand (GOES-W) when the constellation is fully operational. In parallel with the instrument development, a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the higher level algorithms and applications using the GLM alone and decision aids incorporating information from the ABI, ground-based weather radar, and numerical models. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional lightning networks are being used to develop the pre-launch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution. Real time total lightning mapping data are also being provided in an experimental mode to selected National Weather Service (NWS) national centers and forecast offices via the GOES-R Proving Ground to help improve our understanding of the application of these data in operational settings and facilitate early on-orbit user readiness for this new capability.

Goodman, Steven J.; Blakeslee, Richard; Koshak, William; Petersen, Walter; Carey, Larry; Mach, Douglas; Buechler, Dennis; Bateman, Monte; McCaul, Eugene; Bruning, Eric; Albrecht, Rachel; MacGorman, Donald

2010-01-01

178

Design of Attitude Stability System for Prolate Dual-spin Satellite in Its Inclined Elliptical Orbit  

E-print Network

In general, most of communication satellites were designed to be operated in geostationary orbit. And many of them were designed in prolate dual-spin configuration. As a prolate dual-spin vehicle, they have to be stabilized against their internal energy dissipation effect. Several countries that located in southern hemisphere, has shown interest to use communication satellite. Because of those countries southern latitude, an idea emerged to incline the communication satellite (due to its prolate dualspin configuration) in elliptical orbit. This work is focused on designing Attitude Stability System for prolate dual-spin satellite in the effect of perturbed field of gravity due to the inclination of its elliptical orbit. DANDE (De-spin Active Nutation Damping Electronics) provides primary stabilization method for the satellite in its orbit. Classical Control Approach is used for the iteration of DANDE parameters. The control performance is evaluated based on time response analysis.

Muliadi, J; Budiyono, A

2008-01-01

179

Destination-directed, packet-switched architecture for a geostationary communications satellite network  

NASA Astrophysics Data System (ADS)

A major goal of the Digital Systems Technology Branch at the NASA Lewis Research Center is to identify and develop critical digital components and technologies that either enable new commercial missions or significantly enhance the performance, cost efficiency, and/or reliability of existing and planned space communications systems. NASA envisions a need for low-data-rate, interactive, direct-to-the-user communications services for data, voice, facsimile, and video conferencing. The network would provide enhanced very-small-aperture terminal (VSAT) communications services and be capable of handling data rates of 64 kbps through 2.048 Mbps in 64-kbps increments. Efforts have concentrated heavily on the space segment; however, the ground segment has been considered concurrently to ensure cost efficiency and realistic operational constraints. The focus of current space segment developments is a flexible, high-throughput, fault-tolerant onboard information-switching processor (ISP) for a geostationary satellite communications network. The Digital Systems Technology Branch is investigating both circuit and packet architectures for the ISP. Destination-directed, packet-switched architectures for geostationary communications satellites are addressed.

Ivancic, William D.; Shalkhauser, Mary Jo; Bobinsky, Eric A.; Soni, Nitin J.; Quintana, Jorge A.; Kim, Heechul; Wager, Paul; Vanderaar, Mark

1993-07-01

180

Plans for EUMETSAT’s Third Generation Meteosat geostationary satellite programme  

NASA Astrophysics Data System (ADS)

The second generation of Meteosat satellites is expected to provide operational services at least until 2015. Considering the time required for the definition phases of new space systems their typical development cycle and the approval of complex programmes, it is necessary to start planning for follow-up geostationary missions already now. EUMETSAT has therefore established a User Consultation Process aimed at capturing the foreseeable high-level user/service needs and priorities of the EUMETSAT Customers and users in the 2015-2025 timeframe. This process led to a first definition of the Third Generation Meteosat (MTG) European geostationary satellite system, which currently consists of a total of five observation missions defined for pre-phase A studies at system level under ESA contract to be started in autumn 2004. The paper gives an overview on the current status of definition of the five observation missions, and a brief description of the MTG schedule and related milestones. Results of scientific studies and presentations/conclusions of MTG User Consultation Workshops and dedicated expert workshops conducted to define the MTG candidate missions are openly available from the EUMETSAT web-page www.eumetsat.de, under the sub-directory 'Preparation of Future Programmes/Meteosat Third Generation (MTG)'.

Stuhlmann, R.; Rodriguez, A.; Tjemkes, S.; Grandell, J.; Arriaga, A.; Bézy, J.-L.; Aminou, D.; Bensi, P.

181

Thermal Physical Property-Based Fusion of Geostationary Meteorological Satellite Visible and Infrared Channel Images  

PubMed Central

Geostationary meteorological satellite infrared (IR) channel data contain important spectral information for meteorological research and applications, but their spatial resolution is relatively low. The objective of this study is to obtain higher-resolution IR images. One common method of increasing resolution fuses the IR data with high-resolution visible (VIS) channel data. However, most existing image fusion methods focus only on visual performance, and often fail to take into account the thermal physical properties of the IR images. As a result, spectral distortion occurs frequently. To tackle this problem, we propose a thermal physical properties-based correction method for fusing geostationary meteorological satellite IR and VIS images. In our two-step process, the high-resolution structural features of the VIS image are first extracted and incorporated into the IR image using regular multi-resolution fusion approach, such as the multiwavelet analysis. This step significantly increases the visual details in the IR image, but fake thermal information may be included. Next, the Stefan-Boltzmann Law is applied to correct the distortion, to retain or recover the thermal infrared nature of the fused image. The results of both the qualitative and quantitative evaluation demonstrate that the proposed physical correction method both improves the spatial resolution and preserves the infrared thermal properties. PMID:24919017

Han, Lei; Shi, Lu; Yang, Yiling; Song, Dalei

2014-01-01

182

Thermal physical property-based fusion of geostationary meteorological satellite visible and infrared channel images.  

PubMed

Geostationary meteorological satellite infrared (IR) channel data contain important spectral information for meteorological research and applications, but their spatial resolution is relatively low. The objective of this study is to obtain higher-resolution IR images. One common method of increasing resolution fuses the IR data with high-resolution visible (VIS) channel data. However, most existing image fusion methods focus only on visual performance, and often fail to take into account the thermal physical properties of the IR images. As a result, spectral distortion occurs frequently. To tackle this problem, we propose a thermal physical properties-based correction method for fusing geostationary meteorological satellite IR and VIS images. In our two-step process, the high-resolution structural features of the VIS image are first extracted and incorporated into the IR image using regular multi-resolution fusion approach, such as the multiwavelet analysis. This step significantly increases the visual details in the IR image, but fake thermal information may be included. Next, the Stefan-Boltzmann Law is applied to correct the distortion, to retain or recover the thermal infrared nature of the fused image. The results of both the qualitative and quantitative evaluation demonstrate that the proposed physical correction method both improves the spatial resolution and preserves the infrared thermal properties. PMID:24919017

Han, Lei; Shi, Lu; Yang, Yiling; Song, Dalei

2014-01-01

183

Low earth orbit satellite/terrestrial mobile service compatibility  

NASA Technical Reports Server (NTRS)

Digital cellular mobile 'second generation' systems are now gradually being introduced into service; one such example is GSM, which will provide a digital voice and data service throughout Europe. Total coverage is not expected to be achieved until the mid '90's, which has resulted in several proposals for the integration of GSM with a geostationary satellite service. Unfortunately, because terrestrial and space systems have been designed to optimize their performance for their particular environment, integration between a satellite and terrestrial system is unlikely to develop further than the satellite providing a back-up service. This lack of system compatibility is now being addressed by system designers of third generation systems. The next generation of mobile systems, referred to as FPLMTS (future public land mobile telecommunication systems) by CCIR and UMTS (universal mobile telecommunication system) in European research programs, are intended to provide inexpensive, hand-held terminals that can operate in either satellite, cellular, or cordless environments. This poses several challenges for system designers, not least in terms of the choice of multiple access technique and power requirements. Satellite mobile services have been dominated by the geostationary orbital type. Recently, however, a number of low earth orbit configurations have been proposed, for example Iridium. These systems are likely to be fully operational by the turn of the century, in time for the implementation of FPLMTS. The developments in LEO mobile satellite service technology were recognized at WARC-92 with the allocation of specific frequency bands for 'big' LEO's, as well as a frequency allocation for FPLMTS which included a specific satellite allocation. When considering integrating a space service into the terrestrial network, LEO's certainly appear to have their attractions: they can provide global coverage, the round trip delay is of the order of tens of milliseconds, and good visibility to the satellite is usually possible. This has resulted in their detailed investigation in the European COST 227 program and in the work program of the European Telecommunications Standards Institute (ETSI). This paper will consider the system implications of integrating a LEO mobile service with a terrestrial service. Results will be presented from simulation software to show how a particular orbital configuration affects the performance of the system in terms of area coverage and visibility to a terminal for various locations and minimum elevation angle. Possible network topologies are then proposed for an integrated satellite/terrestrial network.

Sheriff, R. E.; Gardiner, J. G.

1993-01-01

184

A Near-Real-Time Global Geostationary Satellite Cloud and Radiation Retreival System  

NASA Astrophysics Data System (ADS)

Weather prediction models need more quantitative weather information for forecasting and nowcasting. This paper describes a prototype system to provide 3-hourly cloud properties from full-disk geostationary satellites (GEOSat) around the globe. Data from GOES11/12, Meteosat.-9, FY2-C/D and MTSAT is analyzed using a common set of algorithms to derive products including cloud mask, cloud phase, cloud base and top height, optical depth, ice and liquid water path, particle sizes, shortwave albedo and longwave flux. Overlap cloud properties are derived from GOES-12 and Meteosat using the CO2 channel 13.3 um. Active and passive remote sensing data from the surface and other satellites are being used to validate the products. Interactive tools for accessing and viewing the data products are demonstrated. Examples of nowcasting application and assimilation of the cloud products in numerical model are presented and future plans and challenges discussed.

Palikonda, R.; Minnis, P.; Spangenberg, D. A.; Ayers, J. K.; Khaiyer, M. M.; Trepte, Q. Z.; Chang, F.; Heck, P. W.; Chee, T. L.; Nguyen, L.; Nordeen, M.

2009-12-01

185

Detection Of A Geostationary Satellite With The Navy Prototype Optical Interferometer  

NASA Astrophysics Data System (ADS)

Most optical/infrared interferometric observations have targeted stars, since they make the easiest targets because of their high surface brightness. Lower surface brightness targets such as asteroids are more difficult, since those that are small enough not to be resolved out by typical interferometer baselines are too faint to produce detectable fringes within the atmospheric coherence time. We describe our recent success in detecting a non-stellar target, the geostationary communications satellite DirecTV-9S, with a 16 meter baseline of the NPOI, using specularly reflected light when the Sun-satellite-NPOI geometry was favorable. The fringe visibility vs. wavelength suggests a two-component image consisting of a high(er) surface brightness component of 1 m size and a lower surface brightness component of 3 m size. This work is funded by the Office of Naval Research and the Oceanographer of the Navy.

Armstrong, J.; Hindsley, R. B.; Schmitt, H. R.; Vrba, F. J.; Benson, J. A.; Hutter, D. J.

2010-01-01

186

Comparison of Geomagnetically-shielded Solar Energetic Proton Fluxes Observed at Geostationary Orbit by GOES and in Low-earth Orbit by SAMPEX, POES and MetOp  

NASA Astrophysics Data System (ADS)

On the current (13-15) and upcoming (R+) series of NOAA Geostationary Operational Environmental Satellites (GOES), solar protons are observed from each satellite in the eastward and westward directions. Solar protons that arrive at a given location in the inner magnetosphere have energies greater than their geomagnetic cutoffs, which depend on direction of arrival as well as the strength of geomagnetic disturbances. Protons arriving from the west at geostationary orbit (GEO) have much lower geomagnetic cutoff energies than protons arriving from the east. As a result, GOES westward observations of >4 MeV protons are representative of the interplanetary population near Earth and serve as the basis for NOAA's real-time solar radiation storm alerts. While the GOES westward observations are similar to the Solar, Anomalous and Magnetospheric Particle Explorer (SAMPEX) Proton-Electron Telescope (PET) proton observations in the polar cap (above invariant L = 10), GOES eastward observations more closely approximate the PET observations at invariant L = 4-4.5 in low earth orbit (LEO). Therefore, GOES may potentially provide a real-time, two-point estimate of the radial gradient of solar energetic protons between L = 6.6 and L = 4. However, the PET observations at L = 4-4.5 exhibit a much wider range of variability than the GOES eastward observations. Therefore, the purpose of this study is to determine how representative the GOES two-point gradient estimate is as a function of magnetic local time and geographic longitude. The study encompasses the largest solar proton events (SPE) in Solar Cycle 23 and to date in Solar Cycle 24. From April 1998 through December 2006, GOES 10 provides eastward GEO and SAMPEX PET provides LEO observations of large SPEs. The Solar Cycle 24 GEO observations are provided by GOES 13 and 15. From July 1998 to date, the Space Environment Monitors (SEM-2) on the NOAA Polar Operational Environmental Satellites (POES) and EUMETSAT MetOp-A provide SPE observations in additional LEO orbit planes (six as of August 2012). SEM-2 data that are severely contaminated by relativistic electrons are excluded from the study.

Rodriguez, J. V.; Mazur, J. E.; Green, J. C.; Machol, J. L.

2012-12-01

187

Estimation of large scale daily evapotranspiration using geostationary meteorological satellite observations  

NASA Astrophysics Data System (ADS)

Accurate estimate of daily evapotranspiration over large areas is important both for understanding hydrological processes on the earth and for water resources management. Remote sensing observations of land surface have been used to estimate evapotranspiration (ET) over large areas, when point measurements cannot provide such information efficiently because of insufficient coverage density. Conventional methods to estimate regional daily ET are based on extrapolation of instantaneous ET estimates usually from polar-orbiting satellite observations at clear sky moments and assuming clear sky conditions prevailing throughout the day. However, such methods are unable to overcome uncertainties caused by eventual cloud interference along a day course. The new generations of geostationary meteorological satellites having frequent temporal sampling and relatively higher spatial resolution than older generations, carries the promise of solving the problem of time integration to estimate daily ET. Such observations at high temporal resolution are particularly helpful in capturing the diurnal variation of land surface temperature, the most critical land surface parameter in determining the energy partitioning between sensible heat flux and latent heat flux. However, cloud-free measurements during a day may be sparse and not simultaneous for different pixels. A time series analysis technique using Fourier transfer analysis as described in Harmonic Analyze of Time Series (HANTS) is therefore needed to fill the gaps in sparse satellite observations due to clouds contamination. In this research, instantaneous latent heat flux in turn the evapotranspiration is calculated from an energy balance based model SEBS (Surface Energy Balance System) firstly using a set of land surface parameters provided by LandSAF products retrieved from observations of SEVIRI (Spinning Enhanced Visible and Infrared Imager) onboard Meteosat Second Generation (MSG). Secondly, HANTS algorithm is used to reconstruct gap-filled time series of instantaneous ET along a day. In the end, daily evapotranspiration is calculated from the reconstructed gap-filled time series of instantaneous estimation of evapotranspiration. The algorithm validation was done using data from limited number of flux tower sites of CarboEurope project in Europe by comparing the energy balance flux components estimated by SEBS with tower flux measurements. Analyses of daily variation of estimated surface heat fluxes show that the proposed method is able to generate large scale net radiation, sensible, latent, and soil heat fluxes that follow closely daily variation of the courses of these flux components as observed by ground measurements. It was found that abnormal values in the estimated latent heat flux are observed near cloudy pixels. It indicates that pixels close to cloudy pixels may be affected by clouds but not masked in the MSG land surface temperature product. In general, reconstruction of evapotranspiration time-series using HANTS algorithm is demonstrated to be a promising technique to overcome the interference of clouds and preserve inherent trends of evapotranspiration process over a day when applied to a large-scale. HANTS reconstruction is capable to maintain daily variation of evapotranspiration on less cloudy days by keeping good correlation with the ground measurements. However, the technique has proven to be limited to areas with cloud cover less than 60% along a day course. Comparison of the daily total ET estimated from SEBS/MSG/HANTS technique with daily ET calculated using conventional method (using one-time measurements of a day and assuming clear sky throughout a day) has shown that the former is less affected by the intensity of cloud interference along the day.

Jia, L.; Daamen, M.

2009-04-01

188

Derivation and evaluation of land surface temperature from the geostationary operational environmental satellite series  

NASA Astrophysics Data System (ADS)

The Geostationary Operational Environmental Satellites (GOES) have been continuously monitoring the earth surface since 1970, providing valuable and intensive data from a very broad range of wavelengths, day and night. The National Oceanic and Atmospheric Administration's (NOAA's) National Environmental Satellite, Data, and Information Service (NESDIS) is currently operating GOES-15 and GOES-13. The design of the GOES series is now heading to the 4 th generation. GOES-R, as a representative of the new generation of the GOES series, is scheduled to be launched in 2015 with higher spatial and temporal resolution images and full-time soundings. These frequent observations provided by GOES Image make them attractive for deriving information on the diurnal land surface temperature (LST) cycle and diurnal temperature range (DTR). These parameters are of great value for research on the Earth's diurnal variability and climate change. Accurate derivation of satellite-based LSTs from thermal infrared data has long been an interesting and challenging research area. To better support the research on climate change, the generation of consistent GOES LST products for both GOES-East and GOES-West from operational dataset as well as historical archive is in great demand. The derivation of GOES LST products and the evaluation of proposed retrieval methods are two major objectives of this study. Literature relevant to satellite-based LST retrieval techniques was reviewed. Specifically, the evolution of two LST algorithm families and LST retrieval methods for geostationary satellites were summarized in this dissertation. Literature relevant to the evaluation of satellite-based LSTs was also reviewed. All the existing methods are a valuable reference to develop the GOES LST product. The primary objective of this dissertation is the development of models for deriving consistent GOES LSTs with high spatial and high temporal coverage. Proper LST retrieval algorithms were studied according to the characteristics of the imager onboard the GOES series. For the GOES 8-11 and GOES R series with split window (SW) channels, a new temperature and emissivity separation (TES) approach was proposed for deriving LST and LSE simultaneously by using multiple-temporal satellite observations. Two split-window regression formulas were selected for this approach, and two satellite observations over the same geo-location within a certain time interval were utilized. This method is particularly applicable to geostationary satellite missions from which qualified multiple-temporal observations are available. For the GOES M(12)-Q series without SW channels, the dual-window LST algorithm was adopted to derive LST. Instead of using the conventional training method to generate coefficients for the LST regression algorithms, a machine training technique was introduced to automatically select the criteria and the boundary of the sub-ranges for generating algorithm coefficients under different conditions. A software package was developed to produce a brand new GOES LST product from both operational GOES measurements and historical archive. The system layers of the software and related system input and output were illustrated in this work. Comprehensive evaluation of GOES LST products was conducted by validating products against multiple ground-based LST observations, LST products from fine-resolution satellites (e.g. MODIS) and GSIP LST products. The key issues relevant to the cloud diffraction effect were studied as well. GOES measurements as well as ancillary data, including satellite and solar geometry, water vapor, cloud mask, land emissivity etc., were collected to generate GOES LST products. In addition, multiple in situ temperature measurements were collected to test the performance of the proposed GOES LST retrieval algorithms. The ground-based dataset included direct surface temperature measurements from the Atmospheric Radiation Measurement program (ARM), and indirect measurements (surface long-wave radiation observations) from the SURFace RADiation Budget (SURF

Fang, Li

189

Linked Autonomous Interplanetary Satellite Orbit Navigation  

NASA Technical Reports Server (NTRS)

A navigation technology known as LiAISON (Linked Autonomous Interplanetary Satellite Orbit Navigation) has been known to produce very impressive navigation results for scenarios involving two or more cooperative satellites near the Moon, such that at least one satellite must be in an orbit significantly perturbed by the Earth, such as a lunar halo orbit. The two (or more) satellites track each other using satellite-to-satellite range and/or range-rate measurements. These relative measurements yield absolute orbit navigation when one of the satellites is in a lunar halo orbit, or the like. The geometry between a lunar halo orbiter and a GEO satellite continuously changes, which dramatically improves the information content of a satellite-to-satellite tracking signal. The geometrical variations include significant out-of-plane shifts, as well as inplane shifts. Further, the GEO satellite is almost continuously in view of a lunar halo orbiter. High-fidelity simulations demonstrate that LiAISON technology improves the navigation of GEO orbiters by an order of magnitude, relative to standard ground tracking. If a GEO satellite is navigated using LiAISON- only tracking measurements, its position is typically known to better than 10 meters. If LiAISON measurements are combined with simple radiometric ground observations, then the satellite s position is typically known to better than 3 meters, which is substantially better than the current state of GEO navigation. There are two features of LiAISON that are novel and advantageous compared with conventional satellite navigation. First, ordinary satellite-to-satellite tracking data only provides relative navigation of each satellite. The novelty is the placement of one navigation satellite in an orbit that is significantly perturbed by both the Earth and the Moon. A navigation satellite can track other satellites elsewhere in the Earth-Moon system and acquire knowledge about both satellites absolute positions and velocities, as well as relative positions and velocities in space. The second novelty is that ordinarily one requires many satellites in order to achieve full navigation of any given customer s position and velocity over time. With LiAISON navigation, only a single navigation satellite is needed, provided that the satellite is significantly affected by the gravity of the Earth and the Moon. That single satellite can track another satellite elsewhere in the Earth- Moon system and obtain absolute knowledge of both satellites states.

Parker, Jeffrey S.; Anderson, Rodney L.; Born, George H.; Leonard, Jason M.; McGranaghan, Ryan M.; Fujimoto, Kohei

2013-01-01

190

GEOS-C orbit determination with Satellite to Satellite Tracking  

NASA Technical Reports Server (NTRS)

This report studies the feasibility of employing satellite to satellite tracking in lieu of ground based tracking to satisfy the orbit determination requirements of the GEOS-C mission. It is shown that with proper estimation procedures it is possible to obtain from Satellite to Satellite Tracking data a GEOS-C orbit whose altitude error averages about 1 meter. The usefulness of this data type for geopotential recovery is also indicated.

Argentiero, P.; Garza-Robles, R.

1975-01-01

191

Hurricane Katrina Satellite Imagery  

NSDL National Science Digital Library

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

National Environmental Satellite, Data, and Information Service

192

Destination directed packet switch architecture for a 30/20 GHz FDMA/TDM geostationary communication satellite network  

NASA Technical Reports Server (NTRS)

Emphasis is on a destination directed packet switching architecture for a 30/20 GHz frequency division multiplex access/time division multiplex (FDMA/TDM) geostationary satellite communication network. Critical subsystems and problem areas are identified and addressed. Efforts have concentrated heavily on the space segment; however, the ground segment was considered concurrently to ensure cost efficiency and realistic operational constraints.

Ivancic, William D.; Shalkhauser, Mary JO

1991-01-01

193

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

Code of Federal Regulations, 2010 CFR

...frequencies allocated to the fixed-satellite service. 25.278 Section 25.278 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Operations §...

2010-10-01

194

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

Code of Federal Regulations, 2014 CFR

...frequencies allocated to the fixed-satellite service. 25.278 Section 25.278 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Operations §...

2014-10-01

195

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

Code of Federal Regulations, 2013 CFR

...frequencies allocated to the fixed-satellite service. 25.278 Section 25.278 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Operations §...

2013-10-01

196

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

Code of Federal Regulations, 2012 CFR

...frequencies allocated to the fixed-satellite service. 25.278 Section 25.278 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Operations §...

2012-10-01

197

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

Code of Federal Regulations, 2011 CFR

...frequencies allocated to the fixed-satellite service. 25.278 Section 25.278 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Operations §...

2011-10-01

198

Cloud pattern prediction from geostationary meteorological satellite images for solar energy forecasting  

NASA Astrophysics Data System (ADS)

Surface solar radiation forecasting permits to predict photovoltaic plant production for a massive and safe integration of solar energy into the electric network. For short-term forecasts (intra-day), methods using images from meteorological geostationary satellites are more suitable than numerical weather prediction models. Forecast schemes consist in assessing cloud motion vectors and in extrapolating cloud patterns from a given satellite image in order to predict cloud cover state above a PV plant. Atmospheric motion vectors retrieval techniques have been studied for several decades in order to improve weather forecasts. However, solar energy forecasting requires the extraction of cloud motion vectors on a finer spatial- and time-resolution than those provided for weather forecast applications. Even if motion vector retrieval is a wide research field in image processing related topics, only block-matching techniques are operationally used for solar energy forecasts via satellite images. In this paper, we propose two motion vectors extraction methods originating from video compression techniques (correlation phase and optical flow methods). We implemented them on a 6-day dataset of Meteosat-10 satellite diurnal images. We proceeded to cloud pattern extrapolation and compared predicted cloud maps against actual ones at different time horizons from 15 minutes to 4 hours ahead. Forecast scores were compared to the state-of-the-art (block matching) method. Correlation phase methods do not outperform block-matching but their computation time is about 25 times shorter. Optical flow based method outperforms all the methods with a satisfactory time computing.

Cros, S.; Sébastien, N.; Liandrat, O.; Schmutz, N.

2014-10-01

199

Next Generation Geostationary Operational Environmental Satellite (GOES-R Series): A Space Segment Overview  

NASA Technical Reports Server (NTRS)

The next-generation National Oceanic and Atmospheric Administration (NOAA) Geostationary Operational Environmental Satellite (GOES-R series) is currently being developed by NOAA in cooperation with the National Aeronautics and Space Administration (NASA). The GOES-R series satellites represents a significant improvement in spatial, temporal, and spectral observations (several orders of magnitude) over the capabilities of the currently operational GOES-1 series and the about to be launched GOES-N series satellite. The GOES-R series will incorporate technically advanced third-generation instruments and spacecraft enhancements to meet evolving observational requirements of forecasting for the era 2012-2025. The GOES-R instrument complement being developed includes a Advanced Baseline Imager (ABI), a Hyperspectral Environmental Suite (HES), a GEO Lighting Mapper (GLM), a Solar Imaging Suite (SIS) and a Space Environment In-Situ Suite (SEISS). Also, candidates for a number of GOES-R Pre-Planned Product Improvements (P(sup 3)Is) includes a Geo microwave Sounder, a Coronograph, a Hyperspectral Imager, and a Solar Irradiance Sensor. Currently, the GOES-R Space Segment architecture is being evaluated as part of a GOES-R system end-to-end architecture study. The GOES-R notional baseline architecture is a constellation of two satellites (A-sat and B-sat) each nominally located at 75 degrees west longitude and at 135 degrees west longitude at geostationary altitude, 0 degrees inclination. The primary mission of the A-sat is to provide imaging from the ABI. The A-sat will also contain the SIS and the GLM. The primary mission of the B-sat is to provide sounding of the hemispherical disk of the earth from the HES. The B-sat also contains the SEISS. Both satellites have mesoscale capabilities for severe weather sounding or imaging. This paper overviews the GOES-R Space Segment development including satellite constellation trade-off, improvements and differences between the current and future instrument and spacecraft capabilities, and technology infusion.

Krimchansky, Alexander; Machi, Dino; Cauffman, Sandra A.; Davis, Martin A.

2004-01-01

200

THE ORBITS OF THE OUTER URANIAN SATELLITES  

SciTech Connect

We report on the numerically integrated orbits for the nine outer Uranian satellites. The orbits are calculated based on fits to the astrometric observations for the period from 1984 to 2006. The results include the state vectors, post-fit residuals, and mean orbital elements. We also assess the accuracy of the orbital fits and discuss the need for future measurements.

Brozovic, M.; Jacobson, R. A. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States)], E-mail: marina.brozovic@jpl.nasa.gov

2009-04-15

201

An Analytical Satellite Orbit Predictor (ASOP)  

NASA Technical Reports Server (NTRS)

The documentation and user's guide for the Analytical Satellite Orbit Predictor (ASOP) computer program is presented. The ASOP is based on mathematical methods that represent a new state-of-the-art for rapid orbit computation techniques. It is intended to be used for computation of near-earth orbits including those of the shuttle/orbiter and its payloads.

Starke, S. E.

1977-01-01

202

GEOSTATIONARY SATELLITE BASED RAINFALL ESTIMATION AND VALIDATION: A CASE STUDY OF JAVA ISLAND, INDONESIA  

NASA Astrophysics Data System (ADS)

Near real time rainfall information is necessary for early warning of rainfall triggered hazard such as floods and landslides. Remote sensing based rainfall estimation has been considered to be used to fulfill that purpose. This research is addressed to use geostationary based rainfall estimation by using Multi Transport Satellite (MTSAT) data which is blended with Tropical Rainfall Measuring Mission (TRMM) 2A12 datasets in order to provide near real time rainfall information, especially for hazard study purposes over Java Island, Indonesia. Comparison to TRMM Multi Precipitation Analysis (TMPA) datasets is performed. Spatial and temporal validation of those rainfall estimations is conducted by validating them with available rain gauge data during a rainy season in December 2007. Temporal validation result shows that TMPA demonstrated better statistical performance than MTSAT blended. However for the spatial correlation, MTSAT blended shows relatively better performance than TMPA.

Suseno, Dwi Prabowo Yuga; Yamada, Tomohito J.

203

True Color Images of the Earth created with the Geostationary Satellite Instrument MSG SEVIRI  

NASA Astrophysics Data System (ADS)

One of the most famous pictures ever taken was by the crew of Apollo 17 in 1972, showing our Earth from a distance of about 45000km. This picture was named 'Blue Marble' and it reminds us of the beauty and uniqueness of our home planet. With geostationary satellites, such views of the Earth are possible without the need to have a photographer in space. However, up to the present, the production of such Blue Marble type images from geostationary satellite data has been impaired by the lack of channels in the visible spectral region. A method for the generation of full disk MSG (METEOSAT Second Generation) SEVIRI (Scanning-Enhanced Visible and Infrared Imager) true colour composite images will be presented. The algorithm mainly uses the SEVIRI channels VIS006 (0.6?m), NIR008 (0.8?m) and NIR016 (1.6?m). The lack of information in the blue and green parts of the visible spectrum is compensated by using data from NASA's (National Aeronautics and Space Administration's) Blue Marble next generation (BMNG) project to fill a look-up table (LUT) transforming RGB (red/green/blue) false colour composite images of VIS006/NIR008/NIR016 into true colour images. Tabulated radiative transfer calculations of a pure Rayleigh atmosphere are used to add an impression of Rayleigh scattering towards the sunlit horizon. The resulting images satisfy naive expectations: clouds are white or transparent, vegetated surfaces are greenish, deserts are sandy-coloured, the ocean is dark blue to black and a narrow halo due to Rayleigh scattering is visible at the sunlit horizon. Therefore, such images are easily interpretable also for inexperienced users not familiar with the characteristics of typical MSG false colour composite images. The images can be used for scientific applications to illustrate specific meteorological conditions or for non-scientific purposes, for example, for raising awareness in the public of the Earth's worthiness of protection.

Reuter, Maximilian

2013-04-01

204

Low-Earth orbit satellite servicing economics  

NASA Technical Reports Server (NTRS)

Servicing economics of low Earth orbit satellites were studied. The following topics are examined: the economic importance of the repair missions; comparison of mission cost as opposed to satellite modulation transfer functions over a 10 year period; the effect of satellite flight rate change due to changes in satellite failure rate; estimated satellite cost reduction with shuttle operation projects from the 1960's to the 1970's; design objectives of the multimission modular spacecraft; and the economic importance of the repair mission.

Davis, R. F.; Cepollina, F. J.

1982-01-01

205

Characterization of urban heat island effects over Asian megacities with hourly LST maps derived from Japanese geostationary satellite data  

NASA Astrophysics Data System (ADS)

Asian countries are expected to continue economic growth with high rate and urban structure can be transformed dramatically. Urbanization and increase in anthropogenic energy consumption cause urban heat island effect. And, Heat island effect increases cooling cost in summer and induces health problem such as heat stroke. Remotely sensed data can be powerful tool to characterize urban area and measure urban thermal conditions, because it is able to capture spatio-temporal variations in urban environments. Japanese geostationary meteorological satellite, MTSAT which covers east Asia and the western Pacific region from 140 degrees East above the equator was launched in February 2005. MTSAT provides hourly visible and thermal infrared image, and hourly Land Surface Temperature (LST) can be retrieved. Therefore, compared to polar orbiting satellites such as MODIS or AVHRR, MTSAT is expected to characterize urban thermal conditions in much detailed temporal scale. In this study, in order to evaluate thermal conditions over Asian megacities with MTSAT data, we investigated methodology for monitoring urban LST with satellite data and characterize thermal conditions by using hourly LST data. Firstly, LST were retrieved from MTSAT thermal infrared data with split-window algorithm, and it was confirmed that MTSAT is able to capture hourly spatio-temporal changes and detect urban heat island effects. Then, we constructed LST database of Asian megacities and the database was open to public on the WWW (http://eiserv.uee.kyoto-u.ac.jp/MTSAT/LST/index_e.php). Finally, by using developed LST database, characteristics of hourly temperature changes of Asian megacities were compared and categorized. And it is found that these characteristics were depend on urban structure of each city. Near-real time land surface temperature (LST) monitoring system on the WWW. Latest LST images of Asian megacities are displayed on the top page.

Oyoshi, K.; Tamura, M.

2009-12-01

206

Short Range Solar Forecasting Using Geostationary Satellite and High Resolution Model Data  

NASA Astrophysics Data System (ADS)

A blended technique utilizing observations and retrievals of cloud properties from geostationary satellite platforms combined with high-resolution mesoscale model data is applied to short-term (0-6hr) forecasts of surface insolation for solar power generation. GOES observations of the continental United States (CONUS), combined with cloud property retrievals including cloud type and cloud top height are used to create a database of cloud cover by cloud steering height. Combined with forecast model wind guidance, satellite-observed clouds can be advected forward in time by model winds to give a short-term forecast of cloud location. This information, when combined with a radiative transfer model, and accounting for variables such as solar geometry, can be used to provide an improved surface insolation forecast over current empirical methods. Additionally, model output from the High-Resolution Rapid Refresh (HRRR) model is being evaluated for potential use as an insolation forecast model. Mesoscale models utilizing real-time platforms such as the WSR-88D network for initialization show promise in forecasting cloud position and therefore insolation. Blending these model forecasts with satellite-derived cloud advection forecasts promises to greatly improve the accuracy and timeliness of insolation forecasts for the growing solar power industry.

Rogers, M. A.; Miller, S. D.

2011-12-01

207

Satellite orbit determination and power subsystem design  

Microsoft Academic Search

One of the most important problems in mission planning and satellite command and control is being able to accurately predict orbital motion, because the trajectory of a spacecraft is a fundamental design parameter with major implications for all subsystems. The purpose of this paper is to present, first, the simulation of the satellite orbit analysis based on data collected from

S. Chouraqui; M. Bekhti; C. I. Underwood

2003-01-01

208

Orbital motion of the solar power satellite  

NASA Technical Reports Server (NTRS)

A study on the effects of solar radiation pressure on the SPS orbit is documented. It was shown that the eccentricity of the orbit can increase from initially being zero. The SPS configuration is primarily considered but the results are applicable to any geosynchronous satellite that resembles a flat surface continually facing the sun. The orbital evolution of the SPS was investigated over its expected 30 year lifetime and the satellite was assumed to be in free flight. The satellite's motion was described with analytical formulae which could be used to develop an orbit control theory in order to minimize station keeping costs.

Graf, O. F., Jr.

1977-01-01

209

Space weather radiation effects on geostationary satellite solid-state power amplifiers  

NASA Astrophysics Data System (ADS)

In order to understand and mitigate the effects of space weather on the performance of geostationary (GEO) communications satellites, we analyze 16 years of archived telemetry data from Inmarsat, the UK-based telecommunications company. We compare 665,112 operational hours of housekeeping telemetry from two generations of satellites, designated as Fleet A and Fleet B. Each generation experienced 13 solid-state power amplifier (SSPA) anomalies for a total of 26 anomalies from 1996 to 2012. We compare telemetry from the Inmarsat anomalies with space weather observations, including data from the OMNI2 database, Geostationary Operational Environmental Satellites, the Advanced Composition Explorer Satellite, and Los Alamos National Laboratory (LANL) GEO observations; the evolution of the sunspot number; and the Kp index. Most SSPA anomalies for Fleet A occur as solar activity declines; Fleet B has not yet experienced a full solar cycle. For both fleets, the average value of Kp remained < 2 over time periods of 2 days, 3 days, and 2 weeks around the time of anomaly, which suggests that the anomalies occurred at times of relatively quiet geomagnetic activity and that they were probably not solely caused by surface charging. From 1996 to 2009, the average of the 1.8-3.5 MeV electron flux was 1.98 #/(cm2 s st keV). Five of the 26 anomalies, unfortunately, do not have corresponding science observations (specifically, electron flux data in the LANL data set), so part of this study focuses on the 21 anomalies when science observations were available. Six out of 21 anomalies experienced a high-energy electron flux greater than 1.5 standard deviations above the mean of the log10 of the flux between 7 and 14 days prior to the anomaly. By contrast, a Monte Carlo simulation finds that on average, only 2.8 out of 21 (13%) of randomly assigned "anomalies" occur between 7 and 14 days after an electron flux greater than 1.5 standard deviations above the mean. Our observations suggest that internal charging from either past elevated radiation belt fluxes or some conditions related to relativistic electron enhancements (either causally or accidentally) is most likely responsible for the SSPA anomalies. We next consider the timing of these anomalies with respect to the local time (LT) and season. Anomalies occur at all LT sectors with 46% (Fleet A) and 38.5% (Fleet B) in the midnight to dawn sector and 54% (Fleet A) and 46% (Fleet B) in the local noon to dusk sector. From the local time distribution, surface charging does not appear to be the sole causative agent of the anomalies. Understanding the connection between the space weather conditions and anomalies on subsystems and specific components on identical and similar geostationary communications satellites for periods of time longer than a solar cycle will help guide design improvements and provide insight on their operation during space weather events.

Lohmeyer, W. Q.; Cahoy, K.

2013-08-01

210

75 FR 17055 - Coordination Between the Non-Geostationary and Geostationary Satellite Orbit  

Federal Register 2010, 2011, 2012, 2013, 2014

...procedures between NGSO FSS space-to-Earth operations and existing fixed service...procedures between NGSO FSS space-to-Earth operations and existing fixed service...prior to the licensing and operation of an earth station, to identify and implement...

2010-04-05

211

Investigating cirrus cloud behavior using A-Train and geostationary satellite data  

NASA Astrophysics Data System (ADS)

Knowledge of how the large-scale dynamics are coupled with microphysical properties is necessary for parameterizing cirrus in climate models. In this study, the synergy of the CloudSat and CALIPSO instruments is exploited for identifying cirrus. Mesoscale-size cirrus events are defined using a combined CloudSat-CALIPSO cloud mask and temperature data for one year in the Atlantic basin. In order to characterize the tendencies of cirrus, the instantaneous view of A-Train satellites is augmented with the temporal view from a geostationary satellite. Cirrus events are tracked using an algorithm, which follows patterns of 6.2?m brightness temperature in consecutive water vapor images. NCEP/NCAR reanalysis data is used to determine the environments in which the cirrus events exist. The cirrus events are sorted based on pressure- radar reflectivity patterns using a k-means cluster algorithm. The six clusters that are identified include Single-Layer Cirrus, Thick Cirrus and Low Cloud, High Cirrus, Deep Cirrus, Mixed Cloud and Thin Cirrus, and Low Cloud. A cluster algorithm is also applied to the large-scale dynamics to determine the basic synoptic states for cirrus. This analysis results in six dynamic clusters including Deep Wave Cirrus, Developing Tropical Cirrus, Subtropical Jet Cirrus, Zonal Jet/Stationary Front Cirrus, Dissipating Tropical Cirrus, and Ridge Crest Cirrus. We find that large-scale dynamic types do not necessarily predetermine the cirrus cloud properties.

Berry, Elizabeth

212

Global Assessment of Land Surface Temperature From Geostationary Satellites and Model Estimates  

NASA Technical Reports Server (NTRS)

Land surface (or 'skin') temperature (LST) lies at the heart of the surface energy balance and is a key variable in weather and climate models. In this research we compare two global and independent data sets: (i) LST retrievals from five geostationary satellites generated at the NASA Langley Research Center (LaRC) and (ii) LST estimates from the quasi-operational NASA GEOS-5 global modeling and assimilation system. The objective is to thoroughly understand both data sets and their systematic differences in preparation for the assimilation of the LaRC LST retrievals into GEOS-5. As expected, mean differences (MD) and root-mean-square differences (RMSD) between modeled and retrieved LST vary tremendously by region and time of day. Typical (absolute) MD values range from 1-3 K in Northern Hemisphere mid-latitude regions to near 10 K in regions where modeled clouds are unrealistic, for example in north-eastern Argentina, Uruguay, Paraguay, and southern Brazil. Typically, model estimates of LST are higher than satellite retrievals during the night and lower during the day. RMSD values range from 1-3 K during the night to 2-5 K during the day, but are larger over the 50-120 W longitude band where the LST retrievals are derived from the FY2E platform

Reichle, Rolf H.; Liu, Q.; Minnis, P.; daSilva, A. M., Jr.; Palikonda, R.; Yost, C. R.

2012-01-01

213

0.5-4 Å X-RAY BRIGHTENINGS IN THE MAGNETOSPHERE OBSERVED BY THE GEOSTATIONARY OPERATIONAL ENVIRONMENTAL SATELLITES  

SciTech Connect

We found 217 X-ray brightening events in Earth's magnetosphere. These events occur in the high-energy band (0.5-4 Å) of the Geostationary Operational Environmental Satellite (GOES) X-ray light curves, although GOES X-ray light curves are frequently used as indices of solar flare magnitudes. We found that (1) brightening events are absent in the low-energy band (1-8 Å), unlike those associated with solar flares; and (2) the peak fluxes, durations, and onset times of these events depend on the magnetic local time (MLT). The events were detected in 2006, 2010, and 2011 at around 19-10 MLT, that is, from night to morning. They typically lasted for 2-3 hr. Their peak fluxes are less than 3 × 10{sup –8} W m{sup –2} in the 0.5-4 Å band and are maximized around 0-5 MLT. From these MLT dependencies, we constructed an MLT time profile of X-ray brightening events. Because 0.5-4 and 1-8 Å fluxes were observed and had the same order of magnitude when GOES 14 passed through Earth's shadow, we expected that X-ray brightening events in the 1-8 Å band are obscured by high-background X-ray fluxes coming from the Sun. We also found coincidence between X-ray brightening events and aurora substorms. In the majority of our events, the minimum geomagnetic field values (AL index) are below –400 nT. From these results and consideration of the GOES satellite orbit, we expect that these X-ray brightening events occur in the magnetosphere. We cannot, however, clarify the radiative process of the observed X-ray brightening events.

Yamamoto, Tetsuya T.; Miyoshi, Y., E-mail: tyamamot@stelab.nagoya-u.ac.jp [Solar-Terrestrial Environment Laboratory, Nagoya University, Aichi (Japan)

2013-10-01

214

Estimates of surface ultraviolet radiation over north America using Geostationary Operational Environmental Satellites observations  

Microsoft Academic Search

Information on ultraviolet (UV) radiative fluxes is needed for public safety, understanding biodiversity, and for chemical transport modeling. Space-based observations can provide homogeneous and systematic estimates of the UV flux over large regions. In the past, UV flux estimates have been made from polar orbiting satellites; such estimates lack information on diurnal variability that can result in significant errors in

H. Gadhavi; R. T. Pinker; I. Laszlo

2008-01-01

215

An Analytical Satellite Orbit Predictor (ASOP)  

NASA Technical Reports Server (NTRS)

The documentation and user's guide are presented for the analytical satellite orbit predictor computer program which is intended to be used for computation of near-earth orbits including those of the shuttle orbiter and its payloads. The Poincare-Similar elements used make it possible to compute near-earth orbits to within an accuracy of a few meters. Recursive equations are used instead of complicated formulas. Execution time is on the order of a few milliseconds.

1979-01-01

216

Coastal water quality estimation from Geostationary Ocean Color Imager (GOCI) satellite data using machine learning approaches  

NASA Astrophysics Data System (ADS)

It is important to monitor coastal water quality using key parameters such as chlorophyll-a concentration and suspended sediment to better manage coastal areas as well as to better understand the nature of biophysical processes in coastal seawater. Remote sensing technology has been commonly used to monitor coastal water quality due to its ability of covering vast areas at high temporal resolution. While it is relatively straightforward to estimate water quality in open ocean (i.e., Case I water) using remote sensing, coastal water quality estimation is still challenging as many factors can influence water quality, including various materials coming from inland water systems and tidal circulation. There are continued efforts to accurately estimate water quality parameters in coastal seawater from remote sensing data in a timely manner. In this study, two major water quality indicators, chlorophyll-a concentration and the amount of suspended sediment, were estimated using Geostationary Ocean Color Imager (GOCI) satellite data. GOCI, launched in June 2010, is the first geostationary ocean color observation satellite in the world. GOCI collects data hourly for 8 hours a day at 6 visible and 2 near-infrared bands at a 500 m resolution with 2,500 x 2,500 km square around Korean peninsula. Along with conventional statistical methods (i.e., various linear and non-linear regression), three machine learning approaches such as random forest, Cubist, and support vector regression were evaluated for coastal water quality estimation. In situ measurements (63 samples; including location, two water quality parameters, and the spectra of surface water using a hand-held spectroradiometer) collected during four days between 2011 and 2012 were used as reference data. Due to the small sample size, leave-one-out cross validation was used to assess the performance of the water quality estimation models. Atmospherically corrected radiance data and selected band-ratioed images were used as predictor variables. Results show that support vector regression outperformed the other two machine learning approaches as well as conventional statistical models, yielding calibration R2 of 0.9 and cross validation RMSE of 1.7 mg/m3 for chlorophyll-a concentration, and calibration R2 of 0.97 and cross validation RMSE of 11.4 g/m3 for suspended sediment. Relative importance of the predictor variables was examined and the spatiotemporal patterns of the water quality parameter distribution were analyzed along with tidal information.

Im, Jungho; Ha, Sunghyun; Kim, Yong Hoon; Ha, Hokyung; Choi, Jongkuk; Kim, Miae

2014-05-01

217

47 CFR 25.143 - Licensing provisions for the 1.6/2.4 GHz Mobile-Satellite Service and 2 GHz Mobile-Satellite...  

Code of Federal Regulations, 2013 CFR

...license. In the case of non-geostationary...orbital planes. In the case of geostationary satellites...non-geostationary hybrid satellite system...for U.S. domestic transmission, the amount of capacity...prohibits a charge for the transmission of maritime...

2013-10-01

218

Long-term statistics of laser beam propagation in an optical ground-to-geostationary satellite communications link  

Microsoft Academic Search

A ground-to-space laser communications experiment was conducted to verify the optical interfaces between a laser communications terminal in an optical ground station and an optical payload onboard a geostationary satellite 38 000 km away. The end-to-end optical characteristics such as intensity, sensitivity, wavelength, polarization, and the modulation scheme of optical signals as well as acquisition sequences of the terminals were

Morio Toyoshima; Shiro Yamakawa; Toshihiko Yamawaki; Katsuyoshi Arai; Marcos Reyes García-Talavera; Angel Alonso; Zoran Sodnik; Benoit Demelenne

2005-01-01

219

GEOS-C orbit determination with satellite to satellite tracking  

NASA Technical Reports Server (NTRS)

This report studies the feasibility of employing satellite to satellite tracking in lieu of ground based tracking to satisfy the orbit determination requirements of the GEOS-C mission. It is shown that with proper estimation procedures it is possible to obtain from S.S.T. data a GEOS-C orbit whose altitude error averages about 1 meter. The usefulness of this data type for geopotential recovery is also indicated.

Argentiero, P.; Garza-Robles, R.

1975-01-01

220

Los Alamos geostationary orbit synoptic data set: a compilation of energetic particle data  

SciTech Connect

Energetic electron (30 to 2000 keV) and proton (145 keV to 150 MeV) measurements made by Los Alamos National Laboratory sensors at geostationary orbit 6.6 R/sub E/ are summarized. The data are plotted in terms of daily average spectra, 3-h local time averages, and in a variety of statistical formats. The data summarize conditions from mid-1976 through 1978 (S/C 1976-059) and from early 1977 through 1978 (S/C 1977-007). The compilations correspond to measurements at 35/sup 0/W, 70/sup 0/W, and 135/sup 0/W geographic longitude and, thus, are indicative of conditions at 9/sup 0/, 11/sup 0/, and 4.8/sup 0/ geomagnetic latitude, respectively. Most of this report is comprised of data plots that are organized according to Carrington solar rotations so that the data can be easily compared to solar rotation-dependent interplanetary data. As shown in prior studies, variations in solar wind conditions modulate particle intensity within the terrestrial magnetosphere. The effects of these variations are demonstrated and discussed. Potential uses of the Synoptic Data Set by the scientific and applications-oriented communities are also discussed.

Baker, D.N.; Higbie, P.R.; Belian, R.D.; Aiello, W.P.; Hones, E.W. Jr.; Tech, E.R.; Halbig, M.F.; Payne, J.B.; Robinson, R.; Kedge, S.

1981-08-01

221

Revised Orbits of Saturn's Small Inner Satellites  

NASA Technical Reports Server (NTRS)

We have updated the orbits of the small inner Saturnian satellites using additional Cassini imaging observations through 2007 March. Statistically significant changes from previously published values appear in the eccentricities and inclinations of Pan and Daphnis, but only small changes have been found in the estimated orbits of the other satellites. We have also improved our knowledge of the masses of Janus and Epimetheus as a result of their close encounter observed in early 2006.

Jacobson, R. A.; Spitale, J.; Porco, C. C.; Beurle, K.; Cooper, N. J.; Evans, M. W.; Murray, C. D.

2007-01-01

222

Observations in the thermal IR and visible of a retired satellite in the graveyard orbit, and comparisons to active satellites in GEO  

NASA Astrophysics Data System (ADS)

There exists a population of defunct satellites in the geo-stationary arc that potentially pose a hazard to current and future operational satellites. These drifting, non-station-kept objects have a variety of ages and sizes, and many are trapped in libration orbits around the Earth's two gravitational potential wells (the non-spherical nature of the Earth gives rise to two geo-potential wells or "stable points" that affect objects in geostationary and geosynchronous orbits), whereas others were boosted to higher altitudes into so-called "graveyard" orbits. We have observed several of the approximately 49 objects in libration orbits about the Western stable point (R. Choc, T. Flohrer, and B. Bastida, "Classification of Geosynchronous Objects," Issue 13, ESA/ESOC, February 2011), as well as objects in graveyard orbits. We have carried out an observational campaign utilizing The Aerospace Corporation's 3-13 ?m Broadband Array Spectrograph System (BASS), as well as with several optical sensors to collect data on a representative sample of these objects at a variety of solar phase angles. Here we report on recent BASS observations of a retired satellite in the "graveyard" orbit, and compare them with data we had collected over six years ago, while the satellite was still active. Data are also presented on similar satellites that are still active. We describe our methods, the data collected, our results, and our future plans.

Skinner, Mark A.; Russell, Ray W.; Kelecy, Tom; Gregory, Steve; Rudy, Richard J.; Kim, Daryl L.; Crawford, Kirk

2014-12-01

223

A versatile system for processing geostationary satellite data with run-time visualization capability  

NASA Technical Reports Server (NTRS)

To better predict global climate change, scientists are developing climate models that require interdisciplinary and collaborative efforts in their building. We are currently involved in several such projects but will briefly discuss activities in support of two such complementary projects: the Atmospheric Radiation Measurement (ARM) program of the Department of Energy and Sequoia 2000, a joint venture of the University of California, the private sector, and government agencies. Our contribution to the ARM program is to investigate the role of clouds on the top of the atmosphere and on surface radiance fields through the data analysis of surface and satellite observations and complex modeling of the interaction of radiation with clouds. One of our first ARM research activities involves the computation of the broadband shortwave surface irradiance from satellite observations. Geostationary satellite images centered over the first ARM observation site are received hourly over the Internet network and processed in real time to compute hourly and daily composite shortwave irradiance fields. The images and the results are transferred via a high-speed network to the Sequoia 2000 storage facility in Berkeley, where they are archived These satellite-derived results are compared with the surface observations to evaluate the accuracy of the satellite estimate and the spatial representation of the surface observations. In developing the software involved in calculating the surface shortwave irradiance, we have produced an environment whereby we can easily modify and monitor the data processing as required. Through the principles of modular programming, we have developed software that is easily modified as new algorithms for computation are developed or input data availability changes. In addition, the software was designed so that it could be run from an interactive, icon-driven, graphical interface, TCL-TK, developed by Sequoia 2000 participants. In this way, the data flow can be interactively assessed and altered as needed. In this environment, the intermediate data processing 'images' can be viewed, enabling the investigator to easily monitor the various data processing steps as they progress. Additionally, this environment allows the rapid testing of new processing modules and allows their effects to be visually compared with previous results.

Landsfeld, M.; Gautier, C.; Figel, T.

1995-01-01

224

Flight Paths of Orbiting Satellites  

NSDL National Science Digital Library

This is an activity to help students visualize the relationship of motion, time and space as it relates to objects orbiting the earth. They will be able to track the path of an orbiting object on a globe, plot the path of an orbiting object on a flat world map, and explain that an object orbiting earth on a plane will produce a flight path which appears as wavy lines on the earths surface.

225

Effect of the high-order resonances on the orbital evolution of objects near geostationary orbit  

NASA Astrophysics Data System (ADS)

The area-to-mass ratio of high-orbit space objects is estimated on the basis of positional observations from the SBG telescope at the Kourovka astronomical observatory of the Ural Federal University. The properties of regions where high-order resonances are located are analyzed. The position and sizes of the resonance zones depending on the area-to-mass ratio of objects are determined on the basis of numerical modeling. It is shown that a system transits through the high-order resonances due to secular perturbations of the semimajor axis under the Poynting-Robertson effect. The high-order resonances weakly influence the formation of the stochastic trajectories. The stochastic properties are mostly manifested in evolution of the semimajor axis of the orbit.

Kuznetsov, E. D.; Zakharova, P. E.; Glamazda, D. V.; Kudryavtsev, S. O.

2014-11-01

226

Temporal variation of the cloud top height over the tropical Pacific observed by geostationary satellites  

NASA Astrophysics Data System (ADS)

Stratiform clouds (nimbostratus and cirriform clouds) in the upper troposphere accompanied with cumulonimbus activity cover large part of the tropical region and largely affect the radiation and water vapor budgets there. Recently new satellites (CloudSat and CALIPSO) can give us the information of cloud height and cloud ice amount even over the open ocean. However, their coverage is limited just below the satellite paths; it is difficult to capture the whole shape and to trace the lifecycle of each cloud system by using just these datasets. We made, as a complementary product, a dataset of cloud top height and visible optical thickness with one-hour resolution over the wide region, by using infrared split-window data of the geostationary satellites (AGU fall meeting 2011) and released on the internet (http://database.rish.kyoto-u.ac.jp/arch/ctop/). We made lookup tables for estimating cloud top height only with geostationary infrared observations by comparing them with the direct cloud observation by CloudSat (Hamada and Nishi, 2010, JAMC). We picked out the same-time observations by MTSAT and CloudSat and regressed the cloud top height observation of CloudSat back onto 11?m brightness temperature (Tb) and the difference between the 11?m Tb and 12?m Tb. We will call our estimated cloud top height as "CTOP" below. The area of our coverage is 85E-155W (MTSAT2) and 80E-160W(MTSAT1R), and 20S-20N. The accuracy of the estimation with the IR split-window observation is the best in the upper tropospheric height range. We analyzed the formation and maintenance of the cloud systems whose top height is in the upper troposphere with our CTOP analysis, CloudSat 2B-GEOPROF, and GSMaP (Global Satellite Mapping of Precipitation) precipitation data. Most of the upper tropospheric stratiform clouds have their cloud top within 13-15 km range. The cloud top height decreases slowly when dissipating but still has high value to the end. However, we sometimes observe that a little lower cloud top height (6-10 km) is kept within one-two days. A typical example is observed on 5 January 2011 in a dissipating cloud system with 1000-km scale. This cluster located between 0-10N just west of the International Date Line and moved westward with keeping relatively lower cloud top (6-10 km) over one day. This top height is lower than the ubiquitous upper-tropospheric stratiform clouds but higher than the so-called 'congestus cloud' whose top height is around 0C. CloudSat data show the presence of convective rainfall. It suggests that this cloud system continuously kept making new anvil clouds in a little lower height than usual. We examined the seasonal variation of the distribution of cloud systems with a little lower cloud top height (6-11 km) during 2010-11. The number of such cloud systems is not constant with seasons but frequently increased in some specific seasons. Over the equatorial ocean region (east of 150E), they were frequently observed during the northern winter.

Nishi, N.; Hamada, A.

2012-12-01

227

Analyzing radiometric requirements for diurnal observations of coastal/oceanic waters from geostationary orbits  

NASA Astrophysics Data System (ADS)

Over the decades, ocean color imaging sensors placed in Low Earth Orbits (LEO) have enabled nearly daily measurements of ocean water properties. Such observations, however, are restricted by cloud/atmospheric conditions. More importantly, such systems could not provide sufficient number of measurements to study the diurnal dynamics of coastal/oceanic ecosystems. One way to surmount such limitations is to leverage geo-stationary orbits to significantly improve temporal observations over such dynamical coastal/oceanic environments. In this study, it is desired to examine whether 50% changes in chlorophyll-a concentration (< 1.5 ug?l) on a semi-diurnal basis are above the noise level. To do so, the top-of-atmosphere radiance (Lt) is modeled for the planned GEO-CAPE mission intended for monitoring coastal ecosystem and river plumes. The input to the simulations includes diurnal remote sensing reflectances (Rrs), which are propagated through a moderately clear atmospheric conditions using a radiative transfer code. The simulations are carried out for two footprints to investigate two extremely different sun-sensor geometries. From these simulations, the temporal change in spectral reflectances between the hours relative to an average noise is examined. Based on the preliminary results, it was found that while the signal change is, on average, 13x the average noise for near-nadir footprints, the change in signal, on average, is only 1.5x the average noise level for near-edge footprints at top of the atmosphere. Such a contrast suggests difficulties in retrieving diurnal variability for locations near the edge of the field of regard (FOR).

Pahlevan, Nima; Lee, Zhongping; Hu, Chuanmin; Schott, John R.

2013-06-01

228

Weather, Climate and Air quality data acquired from quasi-geostationary viewing of high latitudes using highly elliptical orbits  

NASA Astrophysics Data System (ADS)

The Arctic multi-year ice cover is disappearing more rapidly than climate models estimate and the Arctic climate is also changing. With declining ice cover, the Arctic Ocean will likely be subject to increased shipping traffic in addition to exploration activity for natural resources with a concomitant increase in air pollution. Thus there is a multifaceted need to monitor the polar region. A number of Canadian government departments, led by the Canadian Space Agency (CSA), are proposing the Polar Communications and Weather (PCW) mission to provide improved communications and critically important meteorological and air quality information for the Arctic using an operational meteorological imager. Two satellites in highly eccentric orbits with apogees at ~ 40,000 km over the Arctic would provide quasi-geostationary viewing over the Arctic with 24-7 coverage in the IR and measure solar reflected light in the summertime. The planned operational meteorological instrument is a 21-channel spectral imager with UV, visible, NIR and MIR channels similar to MODIS and ABI. This presentation will focus on the PHEOS-WCA (Weather, Climate and Air quality) mission, which is an atmospheric science complement to the operational PCW mission. The PHEOS-WCA instrument package consists of FTS and UVS imaging sounders with viewing range of ~4.5 degrees or a field of regard ~ 3400x3400 km2 from near apogee. The spatial resolution at apogee of each imaging sounder is targeted to be 10×10 km2 or better and the image repeat time <2 hours. The characteristics of the PHEOS-WCA measurements will be described, along with the expected retrieval accuracy of various measured constituents. The quasi-stationary viewing will provide the ability to measure the diurnal behavior of atmospheric properties under the satellites and the ability to provide data for weather forecasting and also air quality data assimilation. One of the important goals for PHEMOS-FTS is to measure changes in CO2 and CH4 throughout the day-lit hours in the NIR near apogee. In this presentation we will outline the scientific objectives, status of retrieval algorithms and also the viewing geometry necessary with two satellites.

McElroy, C. T.; Sioris, C. E.; Walker, K. A.; Buijs, H.; Trichtchenko, A.; Garand, L.; Nassar, R.; Martin, R.; Bergeron, M.; O'Neill, N. T.

2013-12-01

229

Time and frequency comparisons in Europe by means of ECS 5 geostationary satellite  

NASA Technical Reports Server (NTRS)

A time synchronization experiment between some European laboratories using the passive television method applied to the signals broadcasted by Eutelsat I-F5 telecommunication satellite was completed in 1990. The results obtained in the last period, when also range measurements from a Telespazio ground station were performed, are analyzed to evaluate the accuracy level of the time comparisons corrected for the effect of the satellite movement with position data obtained either from the European Space Agency (ESA) or from orbit determination with range data entered into GEODYN program of NASA/GSFC.

Cordara, Franco; Pettiti, V.; Cenci, A.; Fermi, M.; Sciarretta, C.

1990-01-01

230

The geo-control system for station keeping and colocation of geostationary satellites  

NASA Technical Reports Server (NTRS)

GeoControl is a compact but powerful and accurate software system for station keeping of single and colocated satellites, which has been developed at the German Space Operations Center. It includes four core modules for orbit determination (including maneuver estimation), maneuver planning, monitoring of proximities between colocated satellites, and interference and event prediction. A simple database containing state vector and maneuver information at selected epochs is maintained as a central interface between the modules. A menu driven shell utilizing form screens for data input serves as the central user interface. The software is written in Ada and FORTRAN and may be used on VAX workstations or mainframes under the VMS operating system.

Montenbruck, O.; Eckstein, M. C.; Gonner, J.

1993-01-01

231

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

PubMed

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. PMID:23529116

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

2013-01-01

232

Satellite Proving Ground for the GOES-R Geostationary Lightning Mapper (GLM)  

NASA Technical Reports Server (NTRS)

The key mission of the Satellite Proving Ground is to demonstrate new satellite observing data, products and capabilities in the operational environment to be ready on Day 1 to use the GOES-R suite of measurements. Algorithms, tools, and techniques must be tested, validated, and assessed by end users for their utility before they are finalized and incorporated into forecast operations. The GOES-R Proving Ground for the Geostationary Lightning Mapper (GLM) focuses on evaluating how the infusion of the new technology, algorithms, decision aids, or tailored products integrate with other available tools (weather radar and ground strike networks; nowcasting systems, mesoscale analysis, and numerical weather prediction models) in the hands of the forecaster responsible for issuing forecasts and warning products. Additionally, the testing concept fosters operation and development staff interactions which will improve training materials and support documentation development. Real-time proxy total lightning data from regional VHF lightning mapping arrays (LMA) in Northern Alabama, Central Oklahoma, Cape Canaveral Florida, and the Washington, DC Greater Metropolitan Area are the cornerstone for the GLM Proving Ground. The proxy data will simulate the 8 km Event, Group and Flash data that will be generated by GLM. Tailored products such as total flash density at 1-2 minute intervals will be provided for display in AWIPS-2 to select NWS forecast offices and national centers such as the Storm Prediction Center. Additional temporal / spatial combinations are being investigated in coordination with operational needs and case-study proxy data and prototype visualizations may also be generated from the NASA heritage Lightning Imaging Sensor and Optical Transient Detector data. End users will provide feedback on the utility of products in their operational environment, identify use cases and spatial/temporal scales of interest, and provide feedback to the developers for adjusted or new products.

Goodman, Steven J.; Gurka, James; Bruning, E. C.; Blakeslee, J. R.; Rabin, Robert; Buechler, D.

2009-01-01

233

HORSESHOE PERIODIC ORBITS FOR SATURN COORBITAL SATELLITES  

E-print Network

HORSESHOE PERIODIC ORBITS FOR SATURN COORBITAL SATELLITES Jaume Llibre and Merc`e Oll'e Dept. Matem conclude that there exist stable horseshoe periodic orbits which fit with the motion of Saturn coorbital­ stricted problem. 1. Introduction In 1981 the successful Voyager flights to Saturn confirmed the existence

Politècnica de Catalunya, Universitat

234

Orbital evolution of Jupiter's 8th satellite  

Microsoft Academic Search

The orbital evolution of Pasiphae, the 8th satellite of Jupiter, has been investigated. Its osculating orbit for the epoch 29 October 1938 was numerically integrated over the interval of 20,000 years. Within the investigated time interval also the question of the Hill's stability has been studied. The Jacobian constant, generalized to the averaged elliptic problem, calculated from positions and velocities

Nina A. Solovaya; Eduard M. Pittich

1994-01-01

235

Future Plan and Recent Activities for the Japanese Follow-on Geostationary Meteorological Satellite Himawari-8/9  

NASA Astrophysics Data System (ADS)

In 1977, Japan launched the first geostationary meteorological satellite " Himawari-1 (GMS-1)" onto the geo-synchronous orbit at 140°E mainly to cover the western Pacific and the east part of Asia as part of a space segment of the Global Observation System (GOS) of the WMO World Weather Watch (WWW) programme up to the present. JMA plans to launch Himawari-8 in summer 2014 and commence its operation in 2015, when Himawari-7 (MTSAT-2) is scheduled to complete its period of operation. The Agency also plans to launch Himawari-9 in 2016. Himawari-8 and -9 carry Advanced Himawari Imager (AHI) units comparable to the Advanced Baseline Imager (ABI) on board GOES-R with the following functions: - Multi-channel capacity (16 channels in visible and infrared bands) - High spatial resolution (0.5 - 1.0 km for visible and 1.0 - 2.0 km for infrared) - High temporal resolution (within 10 minutes for full disk) - Rapid scanning with flexible area selection and scheduling The follow-on satellites will offer high observation potential, which will enable users to analyze cloud properties and extract other meteorological parameters. To make the most of these functions as well as to provide users with effective information from the start of Himawari-8's operation, JMA has set up an environment for the development of new products from the follow-on satellites in collaboration with its Meteorological Satellite Center (MSC) and other internal related divisions in JMA. The Agency also plans to start the development of related products, and is interested in pursuing scientific and prototyping activities in collaboration with Coordination Group for Meteorological Satellites (CGMS) members. This is particularly the case with EUMETSAT and NOAA/NESDIS, which already operate or are preparing to use a new generation of multi-channel imaging instruments (e.g. MSG/MTG, GOES-R). To support these developments, Himawari-8/9 simulated images are generated in two ways - one involving the accumulation of high-spectral-channel observations from hyper sounders such as AIRS and IASI, and the other using radiative transfer computation based on the provisional response functions of Himawari-8/9. To deliver the more accurate satellite observations, it is vital that satellite instrument calibration is of the highest quality and that a capability exists to intercalibrate the satellite sensors. JMA has been participating in the Global Space-Based Inter-Calibration System (GSICS) since the system's establishment in 2007. The primary goal of GSICS is to achieve operational inter-calibration of the space component of the WWW's GOS and Global Earth Observing System of Systems (GEOSS) that addresses the climate, weather forecasting and other environmental needs of WMO Members.

Kurino, T.

2012-12-01

236

Orbital operation for large automated satellites  

NASA Technical Reports Server (NTRS)

Orbital operations concepts for the shuttle launched Large Automated Satellites (LAS) are discussed. It includes the orbital operations elements and the major options for accomplishing each element. This study is based on the preliminary payload information available in Level I and II documents and on orbital operations methods used on past programs, both manned and unmanned. It includes a definition of detailed trade studies which need to be performed as satellite design details and organization responsibilities are defined. The major objectives of this study were to define operational methods and requirements for the long duration LAS missions which are effective and primarily economical to implement.

Lusk, J. L.; Biro, V.

1974-01-01

237

Cloud-Top Height Estimation by Geostationary Satellite Split-Window Measurements using CloudSat Measurements  

NASA Astrophysics Data System (ADS)

Estimation of cloud-top height and visible optical thickness of upper-tropospheric clouds by brightness temperature (TB) measurements of geostationary satellite at two infrared split-window wavelengths was conducted. These cloud parameters were estimated by regressing the measurements of 94-GHz cloud radar onboard CloudSat satellite in terms of TB at 10.8 um (T11) and its difference from TB at 12 um (?T = T11 - T12) measured by geostationary satellite MTSAT-1R. Estimation by geostationary satellite measurements are fairly useful in field campaigns aiming mesoscale cloud systems, where cloud-top heights are compared with the vertical profiles of ground-based measurements such as wind and cloud condensates in a short time interval. Hamada et al. (2008) conducted the estimation of cloud-top height by T11 and ?T measured by GMS-5, using ship-borne cloud radar measurements. However, their ground-based result was limited to the non-rainy clouds, since cloud radar signal is heavily attenuated by precipitation particles. Spaceborne radar measurements enables an estimation of cloud-top height without concern for the existence of precipitation. We examined the dependences of the estimates of cloud-top height on latitude, season, satellite zenith angle, day-night, and land-sea differences. It was shown that these dependences were considered as being uniform in tropics, except for the region with large satellite zenith angle. The dependences on latitude and season were negligible in tropics, while they became the most significant factor affecting the estimates at higher latitudes. Estimation of visible optical thickness was also conducted, although limited to the non-rainy high clouds. The distributions of estimates in TB-?T space were qualitatively consistent with those expected from a simplified radiative transfer equation, although the standard deviations of measurements were slightly large. Since the CloudSat conducts cloud radar observations on a global scale, the method adopted in this study can easily be applied to other current geostationary satellites with split-window channels, yielding hourly estimation map of cloud-top and optical thickness in global scale. We are planning to provide the near real-time product at our Website. Estimates (shading and thin solid contours) and standard deviations of samples (dashed contours) for cloud-top height by T11 and ?T.

Hamada, A.; Nishi, N.

2009-12-01

238

PREDICT: Satellite tracking and orbital prediction  

NASA Astrophysics Data System (ADS)

PREDICT is an open-source, multi-user satellite tracking and orbital prediction program written under the Linux operating system. PREDICT provides real-time satellite tracking and orbital prediction information to users and client applications through: the system console the command line a network socket the generation of audio speechData such as a spacecraft's sub-satellite point, azimuth and elevation headings, Doppler shift, path loss, slant range, orbital altitude, orbital velocity, footprint diameter, orbital phase (mean anomaly), squint angle, eclipse depth, the time and date of the next AOS (or LOS of the current pass), orbit number, and sunlight and visibility information are provided on a real-time basis. PREDICT can also track (or predict the position of) the Sun and Moon. PREDICT has the ability to control AZ/EL antenna rotators to maintain accurate orientation in the direction of communication satellites. As an aid in locating and tracking satellites through optical means, PREDICT can articulate tracking coordinates and visibility information as plain speech.

Magliacane, John A.

2011-12-01

239

ORANGE: Orbital analytical model for geosynchronous satellite  

NASA Astrophysics Data System (ADS)

ORANGE semi-analytical model is an approximate representation of the centered orbital parmeters evolution of a geosynchronous orbit built with the symbolic computation tool MAPLE. The centered orbital parameters from which short term variations are removed and daily average is computed to remove small amplitude variations. The method we have applied consists in expanding the perturbation functions in adapted orbit parameters and incorporating these developments in to the Lagrange equations. All the computations are done with the symbolic computation tool MAPLE which considerably decreases the risk of error and then, also allows us to develop the equation to a higher order. The targeted accuracy is afetr 30 days of extrapolating: 10 meters on the semi-major axis, 10(exp -5) on the eccentricity, 10(exp -3) degrees on the inclination and 10(exp -3) degrees for the mean longitude. This accuracy in a validity domain such as the semi-major axis is closer than 500 km from the geosynchronous one, the eccentricity is lower than 0.01 and the inclination 5 deg, which represents a wide window around a geostationary position.

Campan, Genevieve; Brousse, Pascal

240

or more than 50 years, NOAA has operated earth-observing satellites and collected, processed, and  

E-print Network

F or more than 50 years, NOAA has operated earth- observing satellites and collected, processed in public awareness and preparedness. NOAA satellites scan the globe day and night, sending back an endless orbiting the Earth: geostationary and polar-orbiting satellites. Geostationary Operational Environmental

241

A method for diagnosing surface parameters using geostationary satellite imagery and a boundary-layer model. M.S. Thesis  

NASA Technical Reports Server (NTRS)

A method for diagnosing surface parameters on a regional scale via geosynchronous satellite imagery is presented. Moisture availability, thermal inertia, atmospheric heat flux, and total evaporation are determined from three infrared images obtained from the Geostationary Operational Environmental Satellite (GOES). Three GOES images (early morning, midafternoon, and night) are obtained from computer tape. Two temperature-difference images are then created. The boundary-layer model is run, and its output is inverted via cubic regression equations. The satellite imagery is efficiently converted into output-variable fields. All computations are executed on a PDP 11/34 minicomputer. Output fields can be produced within one hour of the availability of aligned satellite subimages of a target area.

Polansky, A. C.

1982-01-01

242

Lifetimes of lunar satellite orbits  

NASA Technical Reports Server (NTRS)

The Space Exploration Initiative has generated a renewed interest in lunar mission planning. The lunar missions currently under study, unlike the Apollo missions, involve long stay times. Several lunar gravity models have been formulated, but mission planners do not have enough confidence in the proposed models to conduct detailed studies of missions with long stay times. In this report, a particular lunar gravitational model, the Ferrari 5 x 5 model, was chosen to determine the lifetimes for 100-km and 300-km perilune altitude, near-circular parking orbits. The need to analyze orbital lifetimes for a large number of initial orbital parameters was the motivation for the formulation of a simplified gravitational model from the original model. Using this model, orbital lifetimes were found to be heavily dependent on the initial conditions of the nearly circular orbits, particularly the initial inclination and argument of perilune. This selected model yielded lifetime predictions of less than 40 days for some orbits, and other orbits had lifetimes exceeding a year. Although inconsistencies and limitations are inherent in all existing lunar gravity models, primarily because of a lack of information about the far side of the moon, the methods presented in this analysis are suitable for incorporating the moon's nonspherical gravitational effects on the preliminary design level for future lunar mission planning.

Meyer, Kurt W.; Buglia, James J.; Desai, Prasun N.

1994-01-01

243

Energetic particle injections to geostationary orbit: Relationship to flow bursts and magnetospheric state  

NASA Astrophysics Data System (ADS)

To address the mechanism and factors controlling the injection of energetic particles to the geostationary orbit (GEO), we analyzed the appearance of injections at the GEO drift shell as observed by LANL spacecraft in the cases where the flow bursts and associated transient dipolarization were detected at the entry to the inner magnetosphere, in the high beta plasma sheet region on the nightside between 8 and 13 Re. We analyzed two different data sets, one including Geotail observations in 1995-2005 and another including a set of Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations in 2008-2009. We found that only a small portion of all flow bursts at 8-13 Re were associated with particle injection at GEO but that those injection-associated flows had smaller values of plasma tube entropy parameter (PV5/3) as well as larger change of magnetic field north-south component (dBz). This confirms a scenario that the bursty flows at the entry of the inner magnetosphere (8-13 Re) penetrate into GEO and produce there the energetic particles flux increase. According to the bubble theory of magnetotail plasma flows, the probability of the deep plasma penetration critically depends on how stretched the magnetospheric configuration is, and this dependence is statistically confirmed in a large database to be the major factor controlling the occurrence of GEO injections. We suggest using the background plasma tube entropy value in the nightside part of the GEO drift shell as a suitable parameter to predict the probability of particle injection to GEO. One more outcome of this study is that the energetic particle injections cannot reliably serve as a tool to identify the substorm onset times, as has been done in many past studies.

Sergeev, V. A.; Chernyaev, I. A.; Dubyagin, S. V.; Miyashita, Y.; Angelopoulos, V.; Boakes, P. D.; Nakamura, R.; Henderson, M. G.

2012-10-01

244

History of on-orbit satellite fragmentations  

NASA Technical Reports Server (NTRS)

Since the first serious satellite fragmentation occurred in Jun. 1961, and instantaneously increased the total Earth satellite population by more than 400 percent, the issue of space operations within the finite region of space around the Earth has been the subject of increasing interest and concern. The prolific satellite fragmentations of the 1970's and the marked increase in the number of fragmentations in the 1980's served to widen international research into the characteristics and consequences of such events. Plans for large, manned space stations in the next decade and beyond demand a better understanding of the hazards of the dynamic Earth satellite population. The contribution of satellite fragmentations to the growth of the Earth satellite population is complex and varied. The majority of detectable fragmentation debris have already fallen out of orbit, and the effects of 40 percent of all fragmentations have completely disappeared. In this volume, satellite fragmentations are categorized by their assessed nature and to a lesser degree by their effect on the near-Earth space environment. A satellite breakup is the usually destructive disassociation of an orbital payload, rocket body, or structure, often with a wide range of ejecta velocities. A satellite breakup may be accidental or the result of intentional actions, e.g., due to a propulsion system malfunction or a space weapons test, respectively. An anomalous event is the unplanned separation, usually at low velocity, of one or more detectable objects from a satellite which remains essentially intact. Anomalous events can be caused by material deterioration of items such as thermal blankets, protective shields, or solar panels. As a general rule, a satellite breakup will produce considerably more debris, both trackable and non-trackable, than an anomalous event. From one perspective, satellite breakups may be viewed as a measure of the effects of man's activity on the environment, while anomalous events may be a measure of the environment on man-made objects.

Nauer, David J.

1992-01-01

245

History of on-orbit satellite fragmentations  

NASA Astrophysics Data System (ADS)

Since the first serious satellite fragmentation occurred in Jun. 1961, and instantaneously increased the total Earth satellite population by more than 400 percent, the issue of space operations within the finite region of space around the Earth has been the subject of increasing interest and concern. The prolific satellite fragmentations of the 1970's and the marked increase in the number of fragmentations in the 1980's served to widen international research into the characteristics and consequences of such events. Plans for large, manned space stations in the next decade and beyond demand a better understanding of the hazards of the dynamic Earth satellite population. The contribution of satellite fragmentations to the growth of the Earth satellite population is complex and varied. The majority of detectable fragmentation debris have already fallen out of orbit, and the effects of 40 percent of all fragmentations have completely disappeared. In this volume, satellite fragmentations are categorized by their assessed nature and to a lesser degree by their effect on the near-Earth space environment. A satellite breakup is the usually destructive disassociation of an orbital payload, rocket body, or structure, often with a wide range of ejecta velocities. A satellite breakup may be accidental or the result of intentional actions, e.g., due to a propulsion system malfunction or a space weapons test, respectively. An anomalous event is the unplanned separation, usually at low velocity, of one or more detectable objects from a satellite which remains essentially intact. Anomalous events can be caused by material deterioration of items such as thermal blankets, protective shields, or solar panels. As a general rule, a satellite breakup will produce considerably more debris, both trackable and non-trackable, than an anomalous event. From one perspective, satellite breakups may be viewed as a measure of the effects of man's activity on the environment, while anomalous events may be a measure of the environment on man-made objects.

Nauer, David J.

1992-07-01

246

THE ORBITS OF NEPTUNE'S OUTER SATELLITES  

SciTech Connect

In 2009, we used the Subaru telescope to observe all the faint irregular satellites of Neptune for the first time since 2004. These observations extend the data arcs for Halimede, Psamathe, Sao, Laomedeia, and Neso from a few years to nearly a decade. We also report on a search for unknown Neptune satellites in a half-square degree of sky and a limiting magnitude of 26.2 in the R band. No new satellites of Neptune were found. We numerically integrate the orbits for the five irregulars and summarize the results of the orbital fits in terms of the state vectors, post-fit residuals, and mean orbital elements. Sao and Neso are confirmed to be Kozai librators, while Psamathe is a 'reverse circulator'. Halimede and Laomedeia do not seem to experience any strong resonant effects.

Brozovic, Marina; Jacobson, Robert A. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States); Sheppard, Scott S., E-mail: marina.brozovic@jpl.nasa.gov, E-mail: raj@jpl.nasa.gov, E-mail: sheppard@dtm.ciw.edu [Carnegie Institution of Washington, Department of Terrestrial Magnetism, 5241 Broad Branch Road NW, Washington, DC 20015 (United States)

2011-04-15

247

Online Visualization and Analysis of Merged Global Geostationary Satellite Infrared Dataset  

NASA Astrophysics Data System (ADS)

The NASA Goddard Earth Sciences Data Information Services Center (GES DISC) is home of Tropical Rainfall Measuring Mission (TRMM) data archive. The global merged IR product, also known as, the NCEP/CPC 4-km Global (60°N - 60°S) IR Dataset, is one of TRMM ancillary datasets. They are globally-merged (60°N-60°S) pixel-resolution (4 km) IR brightness temperature data (equivalent blackbody temperatures), merged from all available geostationary satellites (GOES-8/10, METEOSAT-7/5 & GMS). The availability of data from METEOSAT-5, which is located at 63E at the present time, yields a unique opportunity for total global (60°N-60°S) coverage. The GES DISC has collected over 8 years of the data beginning from February of 2000. This high temporal resolution dataset can not only provide additional background information to TRMM and other satellite missions, but also allow observing a wide range of meteorological phenomena from space, such as, mesoscale convection system, tropical cyclones, hurricanes, etc. The dataset can also be used to verify model simulations. Despite that the data can be downloaded via ftp, however, its large volume poses a challenge for many users. A single file occupies about 70 MB disk space and there is a total of ~73,000 files (~4.5 TB) for the past 8 years. Because there is a lack of data subsetting service, one has to download the entire file, which could be time consuming and require a lot of disk space. In order to facilitate data access, we have developed a web prototype, the Global Image ViewER (GIVER), to allow users to conduct online visualization and analysis of this dataset. With a web browser and few mouse clicks, users can have a full access to over 8 year and over 4.5 TB data and generate black and white IR imagery and animation without downloading any software and data. Basic functions include selection of area of interest, single imagery or animation, a time skip capability for different temporal resolution and image size. Users can save an animation as a file (animated gif) and import it in other presentation software, such as, Microsoft PowerPoint. These capabilities along with examples will be presented in this poster. The prototype will be integrated into GIOVANNI and existing GIOVANNI capabilities, such as, data download, Google Earth KMZ, etc. will be available. Users will also be able to access other data products in the GIOVANNI family.

Liu, Z.; Ostrenga, D.; Leptoukh, G.; Mehta, A.

2008-12-01

248

Online Visualization and Analysis of Merged Global Geostationary Satellite Infrared Dataset  

NASA Technical Reports Server (NTRS)

The NASA Goddard Earth Sciences Data Information Services Center (GES DISC) is home of Tropical Rainfall Measuring Mission (TRMM) data archive. The global merged IR product also known as the NCEP/CPC 4-km Global (60 degrees N - 60 degrees S) IR Dataset, is one of TRMM ancillary datasets. They are globally merged (60 degrees N - 60 degrees S) pixel-resolution (4 km) IR brightness temperature data (equivalent blackbody temperatures), merged from all available geostationary satellites (GOES-8/10, METEOSAT-7/5 and GMS). The availability of data from METEOSAT-5, which is located at 63E at the present time, yields a unique opportunity for total global (60 degrees N- 60 degrees S) coverage. The GES DISC has collected over 8 years of the data beginning from February of 2000. This high temporal resolution dataset can not only provide additional background information to TRMM and other satellite missions, but also allow observing a wide range of meteorological phenomena from space, such as, mesoscale convection systems, tropical cyclones, hurricanes, etc. The dataset can also be used to verify model simulations. Despite that the data can be downloaded via ftp, however, its large volume poses a challenge for many users. A single file occupies about 70 MB disk space and there is a total of approximately 73,000 files (approximately 4.5 TB) for the past 8 years. In order to facilitate data access, we have developed a web prototype to allow users to conduct online visualization and analysis of this dataset. With a web browser and few mouse clicks, users can have a full access to over 8 year and over 4.5 TB data and generate black and white IR imagery and animation without downloading any software and data. In short, you can make your own images! Basic functions include selection of area of interest, single imagery or animation, a time skip capability for different temporal resolution and image size. Users can save an animation as a file (animated gif) and import it in other presentation software, such as, Microsoft PowerPoint. The prototype will be integrated into GIOVANNI and existing GIOVANNI capabilities, such as, data download, Google Earth KMZ, etc will be available. Users will also be able to access other data products in the GIOVANNI family.

Liu, Zhong; Ostrenga, D.; Leptoukh, G.; Mehta, A.

2008-01-01

249

Orbit Design of Earth-Observation Satellite  

NASA Astrophysics Data System (ADS)

The purpose of this study is to design a reliable orbit for a medium-resolution scientific satellite to observe Earth for developmental issues such as water resources, agricultural, and industrial. To meet this objective this study firstly, defines the mission, secondly, determines mission constraints, thirdly, design the attitude and orbit control system. As for the observation requirements, and the revisit time are provided as a function of the orbital parameters. Initial orbital parameters are obtained by optimal analysis between observation characteristics and attitude and orbit maintenance costs. Long term station-keeping strategies will be provided for the proposed solutions. Impulsive control will be investigated to provide a reliable and affordable attitude and orbit control system.

Owis, Ashraf

250

Orbits of the six new satellites of Neptune  

Microsoft Academic Search

Orbital elements are presented for the six small satellites of Neptune, 1989N1 through 1989N6, discovered by Voyager 2. Details of the image and orbit analyses are examined. The solution for the orbits of the six satellites is presented in terms of geometric classical Keplerian elements. All six are in nearly circular direct orbits; most of the satellites have low inclinations,

Owen W. M. Jr; R. M. Vaughan; S. P. Synnott

1991-01-01

251

Use of geostationary satellite imagery in optical and thermal bands for the estimation of soil moisture status and land evapotranspiration  

NASA Astrophysics Data System (ADS)

For water and agricultural management, there is an increasing demand to monitor the soil water status and the land evapotranspiration. In the framework of the LSA-SAF project (http://landsaf.meteo.pt), we are developing an energy balance model forced by remote sensing products, i.e. radiation components and vegetation parameters, to monitor in quasi real-time the evapotranspiration rate over land (Gellens-Meulenberghs et al, 2007; Ghilain et al, 2008). The model is applied over the full MSG disk, i.e. including Europe and Africa. Meteorological forcing, as well as the soil moisture status, is provided by the forecasts of the ECMWF model. Since soil moisture is computed by a forecast model not dedicated to the monitoring of the soil water status, inadequate soil moisture input can occur, and can cause large effects on evapotranspiration rates, especially over semi-arid or arid regions. In these regions, a remotely sensed-based method for the soil moisture retrieval can therefore be preferable, to avoid too strong dependency in ECMWF model estimates. Among different strategies, remote sensing offers the advantage of monitoring large areas. Empirical methods of soil moisture assessment exist using remotely sensed derived variables either from the microwave bands or from the thermal bands. Mainly polar orbiters are used for this purpose, and little attention has been paid to the new possibilities offered by geosynchronous satellites. In this contribution, images of the SEVIRI instrument on board of MSG geosynchronous satellites are used. Dedicated operational algorithms were developed for the LSA-SAF project and now deliver images of land surface temperature (LST) every 15-minutes (Trigo et al, 2008) and vegetations indices (leaf area index, LAI; fraction of vegetation cover, FVC; fraction of absorbed photosynthetically active radiation, FAPAR) every day (Garcia-Haro et al, 2005) over Africa and Europe. One advantage of using products derived from geostationary satellites is the close monitoring of the diurnal variation of the land surface temperature. This feature reinforced the statistical strength of empirical methods. An empirical method linking land surface morning heating rates and the fraction of the vegetation cover, also known as a ‘Triangle method' (Gillies et al, 1997) is examined. This method is expected to provide an estimation of a root-zone soil moisture index. The sensitivity of the method to wind speed, soil type, vegetation type and climatic region is explored. Moreover, the impact of the uncertainty of LST and FVC on the resulting soil moisture estimates is assessed. A first impact study of using remotely sensed soil moisture index in the energy balance model is shown and its potential benefits for operational monitoring of evapotranspiration are outlined. References García-Haro, F.J., F. Camacho-de Coca, J. Meliá, B. Martínez (2005) Operational derivation of vegetation products in the framework of the LSA SAF project. Proceedings of the EUMETSAT Meteorological Satellite Conference Dubrovnik (Croatia) 19-23 Septembre. Gellens-Meulenberghs, F., Arboleda, A., Ghilain, N. (2007) Towards a continuous monitoring of evapotranspiration based on MSG data. Proceedings of the symposium on Remote Sensing for Environmental Monitoring and Change Detection. IAHS series. IUGG, Perugia, Italy, July 2007, 7 pp. Ghilain, N., Arboleda, A. and Gellens-Meulenberghs, F., (2008) Improvement of a surface energy balance model by the use of MSG-SEVIRI derived vegetation parameters. Proceedings of the 2008 EUMETSAT meteorological satellite data user's conference, Darmstadt, Germany, 8th-12th September, 7 pp. Gillies R.R., Carlson T.N., Cui J., Kustas W.P. and Humes K. (1997), Verification of the triangle method for obtaining surface soil water content and energy fluxes from remote measurements of Normalized Difference Vegetation Index (NDVI) and surface radiant temperature, International Journal of Remote Sensing, 18, pp. 3145-3166. Trigo, I.F., Monteiro I.T., Olesen F. and Kabsch E. (2008) An assessment of remotely sensed land

Ghilain, N.; Arboleda, A.; Gellens-Meulenberghs, F.

2009-04-01

252

Orbit-spectrum sharing between the fixed-satellite and broadcasting-satellite services with applications to 12 GHz domestic systems  

NASA Technical Reports Server (NTRS)

A systematic, tutorial analysis of the general problem of orbit-spectrum sharing among inhomogeneous satellite system is presented. Emphasis is placed on extrapolating and applying the available data on rain attenuation and on reconciling differences in the results of various measurements of the subjective effects of interference on television picture quality. An analytic method is presented for determining the approximate values of the intersatellite spacings required to keep mutual interference levels within prescribed limits when many dissimilar satellites share the orbit. A computer model was developed for assessing the interference compatibility of arbitrary configurations of large numbers of geostationary satellite systems. It is concluded that the band from 11.7 c GHz can be shared effectively by broadcasting-satellite and fixed-satellite systems. Recommendations for future study are included.

Reinhart, E. E.

1974-01-01

253

Visible infrared spin-scan radiometers (VISSR) for the Geostationary Operational Environmental Satellite (GOES) B and C application  

NASA Technical Reports Server (NTRS)

Two visible infrared spin scan radiometer (VISSR) instruments provided for the Geostationary Operational Environmental Satellite B and C (GOES B and C) spacecrafts are described. The instruments are identical to those supplied previously are summarized. A significant number of changes primarily involving corrections of drawing errors and omissions were also performed. All electrical changes were breadboarded (where complexity required this), were incorporated into the test module, and subjected to verification of proper operation throughout fall instrument temperature range. Evaluation of the changes also included design operating safety margins to account for component variations and life.

1977-01-01

254

Evolution of mass density and O+ concentration at geostationary orbit during storm and quiet events  

NASA Astrophysics Data System (ADS)

We investigated mass density ?m and O+ concentration ?O+?nO+/ne (where nO+ and ne are the O+ and electron density, respectively) during two events, one active and one more quiet. We found ?m from observations of Alfvén wave frequencies measured by the GOES, and we investigated composition by combining measurements of ?m with measurements of ion density nMPA,i from the Magnetospheric Plasma Analyzer (MPA) instrument on Los Alamos National Laboratory spacecraft or ne from the Radio Plasma Imager instrument on the Imager for Magnetopause-to-Aurora Global Exploration spacecraft. Using a simple assumption for the He+ density at solar maximum based on a statistical study, we found ?O+ values ranging from near zero to close to unity. For geostationary spacecraft that corotate with the Earth, sudden changes in density for both ?m and ne often appear between dusk and midnight magnetic local time, especially when Kp is significantly above zero. This probably indicates that the bulk (total) ions have energy below a few keV and that the satellites are crossing from closed or previously closed to open drift paths. During long periods that are geomagnetically quiet, the mass density varies little, but ne gradually refills leading to a gradual change in composition from low-density plasma that is relatively cold and heavy (high-average ion mass M ? ?m/ne) to high-density plasma that is relatively cold and light (low M) plasmasphere-like plasma. During active periods we observe a similar daily oscillation in plasma properties from the dayside to the nightside, with cold and light high-density plasma (more plasmasphere-like) on the dayside and hotter and more heavy low-density plasma (more plasma sheet-like) on the nightside. The value of ne is very dependent on whether it is measured inside or outside a plasmaspheric plume, while ?m is not. All of our results were found at solar maximum; previous results suggest that there will be much less O+ at solar minimum under all conditions.

Denton, R. E.; Takahashi, K.; Thomsen, M. F.; Borovsky, J. E.; Singer, H. J.; Wang, Y.; Goldstein, J.; Brandt, P. C.; Reinisch, B. W.

2014-08-01

255

Low Earth Orbit satellite traffic simulator  

NASA Technical Reports Server (NTRS)

This paper describes a significant tool for Low Earth Orbit (LEO) capacity analysis, needed to support marketing, economic, and design analysis, known as a Satellite Traffic Simulator (STS). LEO satellites typically use multiple beams to help achieve the desired communication capacity, but the traffic demand in these beams in usually not uniform. Simulations of dynamic, average, and peak expected demand per beam is a very critical part of the marketing, economic, and design analysis necessary to field a viable LEO system. An STS is described in this paper which can simulate voice, data and FAX traffic carried by LEO satellite beams and Earth Station Gateways. It is applicable world-wide for any LEO satellite constellations operating over any regions. For aeronautical applications to LEO satellites. the anticipates aeronautical traffic (Erlangs for each hour of the day to be simulated) is prepared for geographically defined 'area targets' (each major operational region for the respective aircraft), and used as input to the STS. The STS was designed by Constellations Communications Inc. (CCI) and E-Systems for usage in Brazil in accordance with an ESCA/INPE Statement Of Work, and developed by Analytical Graphics Inc. (AGI) to execute on top of its Satellite Tool Kit (STK) commercial software. The STS simulates constellations of LEO satellite orbits, with input of traffic intensity (Erlangs) for each hour of the day generated from area targets (such as Brazilian States). accumulated in custom LEO satellite beams, and then accumulated in Earth Station Gateways. The STS is a very general simulator which can accommodate: many forms of orbital element and Walker Constellation input; simple beams or any user defined custom beams; and any location of Gateways. The paper describes some of these features, including Manual Mode dynamic graphical display of communication links, to illustrate which Gateway links are accessible and which links are not, at each 'step' of the satellite orbit. In the two Performance Modes, either Channel capacity or Grade Of Service (GOS) for objects (Satellite beams, Gateways, and an entire satellite) are computed respectively by standard traffic table capacity lookup and blocking probability equations. GOS can be input, with number of channels calculated, or number of channels can be input, with GOS calculated. Also described are some of the STS Test Procedure approach and results. AGI plans to make the STS features available through their normal commercial STK products. E-Systems is a co-developer, tester, and user of the STS. The Test Procedure for the STS was prepared by E-Systems, as an independent tester for CCI, to support the CCI delivery of the STS to ESCA, for their customer INPE.

Hoelzel, John

1995-01-01

256

Investigation of halo satellite orbit control  

NASA Technical Reports Server (NTRS)

Calculations are given for Halo satellite orbit control. Previous truncated analytical descriptions were limited and lead to an acceleration error averaging about .000001, which is the 'cost' of a very tight control to the nominal path. The stationkeeping problem is posed so as to permit a looser, optimal three-axis control.

Breakwell, J. V.

1973-01-01

257

Detecting Canopy Water Status Using Shortwave Infrared Reflectance Data From Polar Orbiting and Geostationary Platforms  

Microsoft Academic Search

Various canopy water status estimates have been developed from recent advances in Earth Observation (EO) technology. A promising methodology is based on the sensitivity of shortwave infrared (SWIR) reflectance to variations in leaf water content. This study explores the potential of SWIR-based canopy water status detection from geostationary Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI) data

Rasmus Fensholt; Silvia Huber; Simon R. Proud; Cheikh Mbow

2010-01-01

258

History of on-orbit satellite fragmentations  

NASA Technical Reports Server (NTRS)

The causes of on-orbit fragmentations are varied and may be intentional or accidental. The cause of many fragmentations remains unknown. While a few cases are currently under investigation as on-orbit collision candidates, man is directly responsible for the vast majority of artificial debris polluting the near-Earth space environment. It should be emphasized that the number of fragments listed with each event in this document represent only those debris officially cataloged by NORAD. Each known on-orbit satellite fragementation is described within this document in module format. Also listed are pertinent characteristics of each fragmentation event. Comments regarding the nature of the satellite and additional details of the events are given.

Johnson, N. L.; Gabbard, J. R.; Devere, G. T.; Johnson, E. E.

1984-01-01

259

Nodding feed antenna for communications with satellites in synchronous orbit  

NASA Technical Reports Server (NTRS)

The design, fabrication, and performance of a parabolic, ground receiving antenna system with a feed that nods in one axis producing a maximum beam deviation 1.1 deg from boresight is described. The antenna design was: (1)to lower the weight (and the subsequent cost) of the supporting structure and the actuator motors for a tracking antenna by moving just the feed; (2) to use a manual tracking system eliminating the need for expensive electronic controls or computers; (3) to provide for several hours of unattended operation; and (4)to permit operation of the antenna by unskilled personnel. Also described are some physical and orbital phenomenon that effect the operation or design of the antenna. One is the motion of a nearly geostationary satellite due to gravitational forces from the sun, the moon, and other stellar bodies. Others are the rotation of the nodding axis and the feed polarization as a function of the location of the station on the earth. A comparison of per unit cost was made for one unit and a quantity of 100.

Smetana, J.; Zavesky, R.

1978-01-01

260

Improvement of Aerosol Optical Depth Retrieval over Hong Kong from a Geostationary Meteorological Satellite Using Critical Reflectance with Background Optical Depth Correction  

NASA Technical Reports Server (NTRS)

Despite continuous efforts to retrieve aerosol optical depth (AOD) using a conventional 5-channelmeteorological imager in geostationary orbit, the accuracy in urban areas has been poorer than other areas primarily due to complex urban surface properties and mixed aerosol types from different emission sources. The two largest error sources in aerosol retrieval have been aerosol type selection and surface reflectance. In selecting the aerosol type from a single visible channel, the season-dependent aerosol optical properties were adopted from longterm measurements of Aerosol Robotic Network (AERONET) sun-photometers. With the aerosol optical properties obtained fromthe AERONET inversion data, look-up tableswere calculated by using a radiative transfer code: the Second Simulation of the Satellite Signal in the Solar Spectrum (6S). Surface reflectance was estimated using the clear sky composite method, awidely used technique for geostationary retrievals. Over East Asia, the AOD retrieved from the Meteorological Imager showed good agreement, although the values were affected by cloud contamination errors. However, the conventional retrieval of the AOD over Hong Kong was largely underestimated due to the lack of information on the aerosol type and surface properties. To detect spatial and temporal variation of aerosol type over the area, the critical reflectance method, a technique to retrieve single scattering albedo (SSA), was applied. Additionally, the background aerosol effect was corrected to improve the accuracy of the surface reflectance over Hong Kong. The AOD retrieved froma modified algorithmwas compared to the collocated data measured by AERONET in Hong Kong. The comparison showed that the new aerosol type selection using the critical reflectance and the corrected surface reflectance significantly improved the accuracy of AODs in Hong Kong areas,with a correlation coefficient increase from0.65 to 0.76 and a regression line change from tMI [basic algorithm] = 0.41tAERONET + 0.16 to tMI [new algorithm] = 0.70tAERONET + 0.01.

Kim, Mijin; Kim, Jhoon; Wong, Man Sing; Yoon, Jongmin; Lee, Jaehwa; Wu, Dong L.; Chan, P.W.; Nichol, Janet E.; Chung, Chu-Yong; Ou, Mi-Lim

2014-01-01

261

Combined system for the compensation of the solar pressure-induced disturbing torque for geostationary satellites  

NASA Astrophysics Data System (ADS)

The problem is considered of determining the shape and dimensions of the passive component in a combined system for offsetting the solar pressure-induced disturbing torque for geostationary spacecraft with asymmetrical solar arrays. The problem statement, numerical solution algorithm, and calculated results are presented. The resulting shape, the study suggests, not only has the required compensation properties but is also the most efficient from the standpoint of manufacture and functional reliability.

Shmatov, S. I.; Mordvinkin, A. S.

2014-12-01

262

Geostationary Operational Environmental Satellites (GOES): R series hyperspectral environmental suite (HES) overview  

NASA Astrophysics Data System (ADS)

The Hyperspectral Environmental Suite (HES) instrument is currently under development by the NASA GOES-R Project team within the framework of the GOES Program to fulfill the future needs and requirements of the National Environmental Satellite, Data, and Information Service (NESDIS) Office. As part of the GOES-R instrument complement, HES will provide measurements of the traditional temperature and water vapor vertical profiles with higher accuracy and vertical resolution than obtained through current sounder technologies. HES will provide measurements of the properties of the shelf and coastal waters and back up imaging (at in-situ resolution) for the GOES-R Advanced Baseline Imager (ABI). The HES team is forging the future of remote environmental monitoring with the development of an operational instrument with high temporal, spatial and spectral-resolution and broad hemispheric coverage. The HES development vision includes threshold and goal requirements that encompass potential system solutions. The HES team has defined tasks for the instrument(s) that include a threshold functional complement of Disk Sounding (DS), Severe Weather/Mesoscale Sounding (SW/M), and Shelf and Coastal Waters imaging (CW) and a goal functional complement of Open Ocean (OO) imaging, and back up imaging (at in-situ resolution) for the GOES-R Advanced Baseline Imager (ABI). To achieve the best-value procurement, the GOES-R Project has base-lined a two-phase procurement approach to the HES design and development; a Formulation/study phase and an instrument Implementation phase. During Formulation, currently slated for the FY04-05 timeframe, the developing team(s) will perform Systems Requirements Analysis and evaluation, System Trade and Requirements Baseline Studies, Risk Assessment and Mitigation Strategy and complete a Preliminary Conceptual Design of the HES instrument. The results of the formulation phase will be leveraged to achieve an effective and efficient system solution during the Implementation Phase scheduled to begin FY05 for a resultant FY12 launch. The magnitude of complexity of the HES development requires an appreciation of the technologies required to achieve the functional objectives. To this end, the GOES-R project team is making available all NASA developed technologies to potential HES vendors, including, the NASA New Millennium Program"s (NMP) Earth Observing-3, Geostationary Imaging Fourier Transform Spectrometer (GIFTS) instrument developed technologies, as applicable. It is anticipated that the instrument(s) meeting the HES requirements will be either a dispersive spectrometer or an interferometric spectrometer or perhaps a combination. No instrument configuration is preferred or favored by the Government. This paper outlines the HES development plan; including an overview of current requirements, existing partnerships and the GOES-R project methodologies to achieve the advanced functional objectives of the GOES Program partnership.

Martin, Gene; Criscione, Joseph C.; Cauffman, Sandra A.; Davis, Martin A.

2004-11-01

263

Cost competitive space transportation system for geostationary payloads  

NASA Technical Reports Server (NTRS)

A geostationary satellite system designer will have a number of launch vehicles to consider in the system designs for the 1980s. The Space transportation System (the shuttle orbiter plus upper stage) offers the opportunity for lower system cost in comparison with the expendable launch vehicles. An analysis of a spin stabilized solid rocket motor stage has demonstrated the feasibility of this upper stage concept. A cost competitive Space Transportation System (STS) for geostationary payloads is made possible by achievement of the STS cost goals, multiple launch from the STS orbiter, and a user-provided spin stabilized upper stage.

Jones, C. R.

1976-01-01

264

The Orbits and Masses of Pluto's Satellites  

NASA Astrophysics Data System (ADS)

Abstract (2,250 Maximum Characters): We report on the numerically integrated orbital fits of Pluto's satellites, Charon, Nix, Hydra, and S/2011 (134340) 1, to an extensive set of astrometric, mutual event, and stellar occultation observations over the time interval April 1965 to July 2011. The observations of Charon relative to Pluto have been corrected for the Pluto center-of-figure center-of-light (COF) offset due to the Pluto albedo variations. The most recently discovered satellite S/2012 (134340) 1 is fit with a precessing ellipse because its observation set is insufficient to constrain a numerically integrated orbit. The Pluto system mass is well determined with the current data. However, the Charon’s mass still carries a considerable amount of the uncertainty due to the fact that the primary source of information for the Charon mass is a small quantity of absolute position measurements that are sensitive to the independent motions of Pluto and Charon about the system barycenter. We used bounded-least squares algorithm to try to constrain the masses of Nix, Hydra, and S/2011 (134340) 1, but the current dataset appears to be too sparse for mass determination. The long-term dynamical interaction among the satellites does yield a weak determination of Hydra's mass. We investigated the effect of more astrometry of S/2012 (134340) 1 on the mass determination of the other satellites and found no improvement with the additional data. We have delivered ephemerides based on our integrated orbits to the New Horizons project along with their expected uncertainties at the time of the spacecraft encounter with the Pluto system. Acknowledgments: The research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Brozovic, Marina; Jacobson, R. A.

2013-05-01

265

Estimate of Solar Maximum using the 1-8 \\AA$\\,$Geostationary Operational Environmental Satellites X-ray Measurements  

E-print Network

We present an alternate method of determining the progression of the solar cycle through an analysis of the solar X-ray background. Our results are based on the NOAA Geostationary Operational Environmental Satellites (GOES) X-ray data in the 1-8 \\AA$\\,$band from 1986 - present, covering solar cycles 22, 23, and 24. The X-ray background level tracks the progression of the solar cycle through its maximum and minimum. Using the X-ray data, we can therefore make estimates of the solar cycle progression and date of solar maximum. Based upon our analysis, we conclude that the Sun reached its hemisphere-averaged maximum in Solar Cycle 24 in late 2013. This is within six months of the NOAA prediction of a maximum in Spring 2013.

Winter, L M

2014-01-01

266

Measurement of total electron content with a geostationary satellite during the solar eclipse of March 7, 1970.  

NASA Technical Reports Server (NTRS)

This note deals with the measurement of the total electron content of the ionosphere at the Goddard Space Flight Center, looking towards the geostationary satellite ATS 3 during the solar eclipse of Mar. 7, 1970. Obscuration at this site was nearly total. Faraday rotation was measured with a stationary circularly polarized antenna and a dual-channel phase-lock receiver tuned to 137.350 MHz. By comparing the electrical phase of the two opposite circularly polarized components, a continuous chart recording was made of Faraday rotation vs local time. A depletion of about 25% in electron content was observed from first contact to the time of minimum electron content. The time variations of the electron content during the eclipse are briefly examined in the light of current theories of ionospheric processes.

Rangaswamy, S.; Schmid, P. E.

1971-01-01

267

Sentinels in the Sky: Weather Satellites.  

ERIC Educational Resources Information Center

This publication describes forecasting weather activity using satellites. Information is included on the development of weather satellites, the National Oceanic and Atmospheric Administration (NOAA) Satellite System (including the polar-orbiting satellites), and the Geostationary Operational Environmental Satellite (GOES). The publication…

Haynes, Robert

268

COSPAS-SARSAT Satellite Orbit Predictor, Vol 4  

NASA Technical Reports Server (NTRS)

The satellite orbit predictor is a graphical aid for determining the relationship between the satellite (SARSAT or COSPAS) orbit, antenna coverage of the spacecraft and coverage of the LUTs. The predictor allows the user to quickly visualize if a selected position will probably be detected and is composed of a base map and a satellite track overlay for each satellite. Additionally, a table of equator crossings for each satellite is included.

Friedman, Morton L.; Garrett, James, Major

1984-01-01

269

Monthly mean large-scale analyses of upper-tropospheric humidity and wind field divergence derived from three geostationary satellites  

NASA Technical Reports Server (NTRS)

This paper describes the results from a collaborative study between the European Space Operations Center, the European Organization for the Exploitation of Meteorological Satellites, the National Oceanic and Atmospheric Administration, and the Cooperative Institute for Meteorological Satellite Studies investigating the relationship between satellite-derived monthly mean fields of wind and humidity in the upper troposphere for March 1994. Three geostationary meteorological satellites GOES-7, Meteosat-3, and Meteosat-5 are used to cover an area from roughly 160 deg W to 50 deg E. The wind fields are derived from tracking features in successive images of upper-tropospheric water vapor (WV) as depicted in the 6.5-micron absorption band. The upper-tropospheric relative humidity (UTH) is inferred from measured water vapor radiances with a physical retrieval scheme based on radiative forward calculations. Quantitative information on large-scale circulation patterns in the upper-troposphere is possible with the dense spatial coverage of the WV wind vectors. The monthly mean wind field is used to estimate the large-scale divergence; values range between about-5 x 10(exp -6) and 5 x 10(exp 6)/s when averaged over a scale length of about 1000-2000 km. The spatial patterns of the UTH field and the divergence of the wind field closely resemble one another, suggesting that UTH patterns are principally determined by the large-scale circulation. Since the upper-tropospheric humidity absorbs upwelling radiation from lower-tropospheric levels and therefore contributes significantly to the atmospheric greenhouse effect, this work implies that studies on the climate relevance of water vapor should include three-dimensional modeling of the atmospheric dynamics. The fields of UTH and WV winds are useful parameters for a climate-monitoring system based on satellite data. The results from this 1-month analysis suggest the desirability of further GOES and Meteosat studies to characterize the changes in the upper-tropospheric moisture sources and sinks over the past decade.

Schmetz, Johannes; Menzel, W. Paul; Velden, Christopher; Wu, Xiangqian; Vandeberg, Leo; Nieman, Steve; Hayden, Christopher; Holmlund, Kenneth; Geijo, Carlos

1995-01-01

270

Analysing NDVI for the African continent using the geostationary meteosat second generation SEVIRI sensor  

Microsoft Academic Search

This study presents first results on Normalized Difference Vegetation Index (NDVI), from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) sensor onboard the geostationary satellite Meteosat Second Generation (MSG) covering the African continent. With a temporal resolution of 15 min MSG offers complementary information for NDVI monitoring compared to vegetation monitoring based on polar orbiting satellites. The improved temporal resolution

Rasmus Fensholt; Inge Sandholt; Simon Stisen; Compton Tucker

2006-01-01

271

Satellite Meteorology: Online Remote Sensing Guide  

NSDL National Science Digital Library

This guide presents introductory information about satellites and remote sensing and their uses in meteorological observations and forecasting. Topics include geostationary and polar orbiting satellites, orbital coverage, architecture, instruments, and the types of data they produce. A tutorial on interpreting satellite images is also included.

272

Jupiter orbiter lifetime: The hazard of Galilean satellite collision  

NASA Technical Reports Server (NTRS)

The four Galilean satellites of Jupiter present a long-term collision hazard to an uncontrolled orbiting spacecraft that repeatedly enters the spatial region occupied by the satellites. Satellite close encounters and the likelihood of collision over a wide range of initial orbit conditions were analyzed. The effect of orbit inclination was of key interest. The scope of the analysis was restricted to orbital dynamic considerations alone, i.e. the question of biological contamination given the event of collision was not considered. A quarantine or orbiter lifetime of 50 years was assumed. This time period begins at spacecraft shutdown following completion of the mission objectives. A numerical approach was adopted wherein each initial orbit is propagated for 50 years, and satellite closest encounter distances recorded on every revolution. The computer program includes approximations of the three major perturbation effects on the long-term motion of the orbiter: (1) Jupiter oblateness, (2) solar gravity, and (3) satellite gravity.

Friedlander, A. L.

1975-01-01

273

Aqua satellite orbiting the Earth - Duration: 116 seconds.  

NASA Video Gallery

This animation shows the Aqua satellite orbiting the Earth on August 27, 2005 by revealing MODIS true-color imagery for that day. This animation is on a cartesian map projection, so the satellite w...

274

NASA-Langley Web-Based Operational Real-time Cloud Retrieval Products from Geostationary Satellites  

NASA Technical Reports Server (NTRS)

At NASA Langley Research Center (LaRC), radiances from multiple satellites are analyzed in near real-time to produce cloud products over many regions on the globe. These data are valuable for many applications such as diagnosing aircraft icing conditions and model validation and assimilation. This paper presents an overview of the multiple products available, summarizes the content of the online database, and details web-based satellite browsers and tools to access satellite imagery and products.

Palikonda, Rabindra; Minnis, Patrick; Spangenberg, Douglas A.; Khaiyer, Mandana M.; Nordeen, Michele L.; Ayers, Jeffrey K.; Nguyen, Louis; Yi, Yuhong; Chan, P. K.; Trepte, Qing Z.; Chang, Fu-Lung; Smith, William L, Jr.

2006-01-01

275

The orbital poles of Milky Way satellite galaxies: a rotationally supported disc-of-satellites  

E-print Network

Available proper motion measurements of Milky Way (MW) satellite galaxies are used to calculate their orbital poles and projected uncertainties. These are compared to a set of recent cold dark-matter (CDM) simulations, tailored specifically to solve the MW satellite problem. We show that the CDM satellite orbital poles are fully consistent with being drawn from a random distribution, while the MW satellite orbital poles indicate that the disc-of-satellites of the Milky Way is rotationally supported. Furthermore, the bootstrapping analysis of the spatial distribution of theoretical CDM satellites also shows that they are consistent with being randomly drawn. The theoretical CDM satellite population thus shows a significantly different orbital and spatial distribution than the MW satellites, most probably indicating that the majority of the latter are of tidal origin rather than being DM dominated sub-structures. A statistic is presented that can be used to test a possible correlation of satellite galaxy orbits with their spatial distribution.

Manuel Metz; Pavel Kroupa; Noam I. Libeskind

2008-02-26

276

Stereographic cloud heights from the imagery of two scan-synchronized geostationary satellites  

NASA Technical Reports Server (NTRS)

Scan synchronization of the sensors of two SMS-GOES satellites yields imagery from which cloud heights can be derived stereographically with a theoretical two-sigma random uncertainty of + or - 0.25 km for pairs of satellites separated by 60 degrees of longitude. Systematic height errors due to cloud motion can be kept below 100 m for all clouds with east-west components of speed below hurricane speed, provided the scan synchronization is within 40 seconds at the mid-point latitude, and the spin axis of each satellite is parallel to that of the earth.

Minzner, R. A.; Teagle, R. D.; Steranka, J.; Shenk, W. E.

1979-01-01

277

Generalized Split-Window Algorithm for Estimate of Land Surface Temperature from Chinese Geostationary FengYun Meteorological Satellite (FY2C) Data  

Microsoft Academic Search

On the basis of the radiative transfer theory, this paper addressed the estimate of Land Surface Temperature (LST) from the Chinese first operational geostationary meteorological satellite-FengYun-2C (FY-2C) data in two thermal infrared channels (IR1, 10.3-11.3 m m ? and IR2, 11.5-12.5 ? ), using the Generalized Split-Window (GSW) algorithm proposed by Wan and Dozier (1996). The coefficients in the GSW

Bohui Tang; Yuyun Bi; Zhao-Liang Li; Jun Xia

2008-01-01

278

Operational retrieval of Asian sand and dust storm from FY2C geostationary meteorological satellite and its application to real time forecast in Asia  

Microsoft Academic Search

This paper describes an operational retrieval algorithm for the sand\\/dust storm (SDS) from FY-2C\\/S- VISSR (Stretched-Visible and Infrared Spin-Scan Radiome- ter) developed at the National Satellite Meteorological Cen- ter (NSMC) of China. This algorithm, called Dust Re- trieval Algorithm based on Geostationary Imager (DRAGI), is based on the optical and radiative physical properties of SDS in mid-infrared and thermal infrared

X. Q. Hu; N. M. Lu; T. Niu; P. Zhang

2008-01-01

279

Operational retrieval of Asian sand and dust storm from FY2C geostationary meteorological satellite and its application to real time forecast in Asia  

Microsoft Academic Search

This paper describes an operational retrieval algorithm for the sand\\/dust storm (SDS) from FY-2C\\/S-VISSR (Stretched-Visible and Infrared Spin-Scan Radiometer) developed at the National Satellite Meteorological Center (NSMC) of China. This algorithm, called Dust Retrieval Algorithm based on Geostationary Imager (DRAGI), is based on the optical and radiative physical properties of SDS in mid-infrared and thermal infrared spectral regions as well

X. Q. Hu; N. M. Lu; T. Niu; P. Zhang

2008-01-01

280

Operational retrieval of Asian sand and dust storm from FY2C geostationary meteorological satellite and its application to real time forecast in Asia  

Microsoft Academic Search

This paper describes an operational retrieval algorithm for the sand\\/dust storm (SDS) from FY-2C\\/S-VISSR (Stretched - Visible and Infrared Spin-Scan Radiometer) developed at the National Satellite Meteorological Center (NSMC) of China. This algorithm, called Dust Retrieval Algorithm based on Geostationary Imager (DRAGI), is based on the optical and radiative physical properties of SDS in mid-infrared and thermal infrared spectral regions

X. Q. Hu; N. M. Lu; T. Niu; P. Zhang

2007-01-01

281

Satellite orbital conjunction reports assessing threatening encounters in space (SOCRATES)  

NASA Astrophysics Data System (ADS)

While many satellite operators are aware of the possibility of a collision between their satellite and another object in earth orbit, most seem unaware of the frequency of near misses occurring each day. Until recently, no service existed to advise satellite operators of an impending conjunction of a satellite payload with another satellite, putting the responsibility for determining these occurrences squarely on the satellite operator's shoulders. This problem has been further confounded by the lack of a timely, comprehensive data set of satellite orbital element sets and computationally efficient tools to provide predictions using industry-standard software. As a result, hundreds of conjunctions within 1 km occur each week, with little or no intervention, putting billions of dollars of space hardware at risk, along with their associated missions. As a service to the satellite operator community, the Center for Space Standards & Innovation (CSSI) offers SOCRATES-Satellite Orbital Conjunction Reports Assessing Threatening Encounters in Space. Twice each day, CSSI runs a list of all satellite payloads on orbit against a list of all objects on orbit using the catalog of all unclassified NORAD two-line element sets to look for conjunctions over the next seven days. The runs are made using STK/CAT-Satellite Tool Kit's Conjunction Analysis Tools-together with the NORAD SGP4 propagator in STK. This paper will discuss how SOCRATES works and how it can help satellite operators avoid undesired close approaches through advanced mission planning.

Kelso, T. S.; Alfano, S.

2006-05-01

282

The Use of the Deep Convective Cloud Technique (DCCT) to Monitor On-Orbit Performance of the Geostationary Lightning Mapper (GLM): Use of Lightning Imaging Sensor (LIS) Data as Proxy  

NASA Technical Reports Server (NTRS)

The Geostationary Lightning Mapper (GLM) on the next generation Geostationary Operational Environmental Satellite-R (GOES-R) will not have onboard calibration capability to monitor its performance. The Lightning Imaging Sensor (LIS) onboard the Tropical Rainfall Measuring Mission (TRMM) satellite has been providing observations of total lightning over the Earth's Tropics since 1997. The GLM design is based on LIS heritage, making it a good proxy dataset. This study examines the performance of LIS throughout its time in orbit. This was accomplished through application of the Deep Convective Cloud Technique (DCCT) (Doelling et al., 2004) to LIS background pixel radiance data. The DCCT identifies deep convective clouds by their cold Infrared (IR) brightness temperatures and using them as invariant targets in the solar reflective portion of the solar spectrum. The GLM and LIS operate in the near-IR at a wavelength of 777.4 nm. In the present study the IR data is obtained from the Visible Infrared Sensor (VIRS) which is collocated with LIS onboard the Tropical Rainfall Measuring Mission (TRMM) satellite. The DCCT is applied to LIS observations for July and August of each year from 1998-2010. The resulting distributions of LIS background DCC pixel radiance for each July August are very similar, indicating stable performance. The mean radiance of the DCCT analysis does not show a long term trend and the maximum deviation of the July August mean radiance for each year is within 0.7% of the overall mean. These results demonstrate that there has been no discernible change in LIS performance throughout its lifetime. A similar approach will used for monitoring the performance of GLM, with cold clouds identified using IR data from the Advanced Baseline Imager (ABI) which will also be located on GOES-R. Since GLM is based on LIS design heritage, the LIS results indicate that GLM should also experience stable performance over its lifetime.

Buechler, Dennis E.; Christian, H. J.; Koshak, William J.; Goodman, Steve J.

2013-01-01

283

Geostationary satellite position determination for common-view two-way time transfer measurements  

NASA Technical Reports Server (NTRS)

In common-view two-way time transfer, each earth station receives an unwanted return signal from its own transmission as well as the desired signal from the other earth station. National Institute of Standards and Technology (NIST), the National Research Council (NRC), and the U.S. Naval Observatory (USNO) have been cooperating in a three-corner common-view two-way time transfer experiment. Some systematic effects are known to depend on the position of the satellite (Sagnac effect and the cross-correlation pulling of the pseudo-random codes). A method is presented for deriving accurate satellite ranges from each of three stations doing common-view two-way satellite time transfer measurements, when one (and only one) station also takes ranging measurements on its 'unwanted return signal' for a brief period. The method is applied to determine the variations in position of the satellite used over the course of the NIST/NRC/USNO SBS-3 experiment, with ranging data taken at NRC, where no additional hardware was required to automate the process. The fit and extrapolation which are employed in this method have an estimated precision of 2 m. If the delays of SBS-3 satellite KU band transponder and earth station equipment were measured accurately as well as the tropospheric refractions were well modeled and corrected, we would expect a ranging accuracy of 2.5 m and satellite positioning accuracy would be 200 m (latitude) 50 m (longitude) and 20 m (height above ellipsoid).

Zhuang, Qixiang; Douglas, Robert J.

1992-01-01

284

Implementation of a state of the art automated system for the production of cloud/water vapor motion winds from geostationary satellites  

NASA Technical Reports Server (NTRS)

The research objectives in this proposal were part of a continuing program at UW-CIMSS to develop and refine an automated geostationary satellite winds processing system which can be utilized in both research and operational environments. The majority of the originally proposed tasks were successfully accomplished, and in some cases the progress exceeded the original goals. Much of the research and development supported by this grant resulted in upgrades and modifications to the existing automated satellite winds tracking algorithm. These modifications were put to the test through case study demonstrations and numerical model impact studies. After being successfully demonstrated, the modifications and upgrades were implemented into the NESDIS algorithms in Washington DC, and have become part of the operational support. A major focus of the research supported under this grant attended to the continued development of water vapor tracked winds from geostationary observations. The fully automated UW-CIMSS tracking algorithm has been tuned to provide complete upper-tropospheric coverage from this data source, with data set quality close to that of operational cloud motion winds. Multispectral water vapor observations were collected and processed from several different geostationary satellites. The tracking and quality control algorithms were tuned and refined based on ground-truth comparisons and case studies involving impact on numerical model analyses and forecasts. The results have shown the water vapor motion winds are of good quality, complement the cloud motion wind data, and can have a positive impact in NWP on many meteorological scales.

Velden, Christopher

1995-01-01

285

Satellite orbit and data sampling requirements  

NASA Technical Reports Server (NTRS)

Climate forcings and feedbacks vary over a wide range of time and space scales. The operation of non-linear feedbacks can couple variations at widely separated time and space scales and cause climatological phenomena to be intermittent. Consequently, monitoring of global, decadal changes in climate requires global observations that cover the whole range of space-time scales and are continuous over several decades. The sampling of smaller space-time scales must have sufficient statistical accuracy to measure the small changes in the forcings and feedbacks anticipated in the next few decades, while continuity of measurements is crucial for unambiguous interpretation of climate change. Shorter records of monthly and regional (500-1000 km) measurements with similar accuracies can also provide valuable information about climate processes, when 'natural experiments' such as large volcanic eruptions or El Ninos occur. In this section existing satellite datasets and climate model simulations are used to test the satellite orbits and sampling required to achieve accurate measurements of changes in forcings and feedbacks at monthly frequency and 1000 km (regional) scale.

Rossow, William

1993-01-01

286

Deriving electromagnetic radial diffusion coefficients of radiation belt equatorial particles for different levels of magnetic activity based on magnetic field measurements at geostationary orbit  

NASA Astrophysics Data System (ADS)

In this paper, we show that the correlation that exists between magnetic variations and induced electric fields through Faraday's law is of prime importance for adequately characterizing electromagnetic radial diffusion. Accordingly, we present an approach to derive electromagnetic radial diffusion coefficients based on magnetic field measurements at geostationary orbit. It consists of setting a very simple theoretical electromagnetic field model, considering the magnetic field as a background dipolar field on which two small time disturbances are superimposed: a symmetric disturbance and an asymmetric disturbance. Within this framework, electromagnetic radial diffusion is quantified analytically, taking into account both induced electric and magnetic contributions. The role played by the time variations of the field asymmetry is highlighted. From this, we deduce instantaneous field asymmetries from measurements of the magnetic field at the same time in two different places of the geostationary orbit. Then, we perform a statistical analysis of the time variations of this signal based on more than 7 years of data from the NOAA-GOES 8, NOAA-GOES 10, and NOAA-GOES 12 spacecraft, working with time resolutions of 1 and 5 min. We show that the asymmetry signal is not stationary, having time-dependent statistical properties, and we question accordingly the standard formulation of the electromagnetic radial diffusion coefficient and the role of drift-resonant interactions. Finally, we provide new electromagnetic radial diffusion coefficients at geostationary orbit as a function of electron kinetic energy and Kp index from 0 to 4.

Lejosne, SolèNe; Boscher, Daniel; Maget, Vincent; Rolland, Guy

2013-06-01

287

Orbits of the ten small satellites of Uranus  

SciTech Connect

Orbital elements are presented for the ten small satellites discovered by Voyager 2 at Uranus. These ten new satellites, whose provisional IAU designations are 1985UI and 1986UI through 1986U9, lie for the most part in equatorial, circular orbits; the most notable exception is 1986U8, the outer epsilon-ring shepherd, whose eccentricity e = 0.0101. Unlike the Voyager discoveries at Saturn, which included two co-orbiting satellites and three librators, the ten small Uranian satellites all have quite different semimajor axes. 11 references.

Owen, W.M. Jr.; Synnott, S.P.

1987-05-01

288

Modeling GPS satellite attitude variation for precise orbit determination  

Microsoft Academic Search

High precision geodetic application of the Global Positioning System (GPS) require highly precise ephemerides of the GPS satellites. An accurate model for the non-gravitational forces on the GPS satellites is a key to high quality GPS orbit determination, especially in long arcs. In this paper the effect of the satellite solar panel orientation error is investigated. These effects are approximated

D. Kuang; H. J. Rim; B. E. Schutz; P. A. M. Abusali

1996-01-01

289

Huge "Structure" of Satellites Found Orbiting Milky Way  

E-print Network

Huge "Structure" of Satellites Found Orbiting Milky Way Grouping of galaxies puts cosmology A huge "structure" of satellite galaxies and star clusters has been found wheeling around the Milky Way the locations of the Milky Way's known satellites using sources ranging from 20th- century photographic plates

Belogay, Eugene A.

290

Satellite aided orbit capture. [gravity assist by natural satellites for interplanetary missions  

NASA Technical Reports Server (NTRS)

The paper surveys the developments leading to the use of satellites for orbit control. Previous satellite gravity assist work is analyzed, emphasizing powered and unpowered aided capture schemes. In addition, a parametric study characterizes potential gains of satellite aided capture for various satellite systems. Finally, potential applications of aided capture such as for the Galilean System and for Saturn and Titan are given.

Nock, K. T.; Uphoff, C.

1979-01-01

291

Discovery of 12 satellites of Saturn exhibiting orbital clustering.  

PubMed

The giant planets in the Solar System each have two groups of satellites. The regular satellites move along nearly circular orbits in the planet's orbital plane, revolving about it in the same sense as the planet spins. In contrast, the so-called irregular satellites are generally smaller in size and are characterized by large orbits with significant eccentricity, inclination or both. The differences in their characteristics suggest that the regular and irregular satellites formed by different mechanisms: the regular satellites are believed to have formed in an accretion disk around the planet, like a miniature Solar System, whereas the irregulars are generally thought to be captured planetesimals. Here we report the discovery of 12 irregular satellites of Saturn, along with the determinations of their orbits. These orbits, along with the orbits of irregular satellites of Jupiter and Uranus, fall into groups on the basis of their orbital inclinations. We interpret this result as indicating that most of the irregular moons are collisional remnants of larger satellites that were fragmented after capture, rather than being captured independently. PMID:11449267

Gladman, B; Kavelaars, J J; Holman, M; Nicholson, P D; Burns, J A; Hergenrother, C W; Petit, J M; Marsden, B G; Jacobson, R; Gray, W; Grav, T

2001-07-12

292

Estimation of net surface shortwave radiation over the tropical Indian Ocean using geostationary satellite observations: Algorithm and validation  

NASA Astrophysics Data System (ADS)

This paper presents the development of a methodology to estimate the net surface shortwave radiation (SWR) over tropical oceans using half-hourly geostationary satellite estimates of outgoing longwave radiation (OLR). The collocated data set of SWR measured at 13 buoy locations over the Indian Ocean and a Meteosat-derived OLR for the period of 2002-2009 have been used to derive an empirical relationship. The information from the solar zenith angle that determines the amount of solar radiation received at a particular location is used to normalize the SWR to nadir observation in order to make the empirical relationship location independent. As the relationship between SWR and OLR is valid mostly over the warm-pool regions, the present study restricts SWR estimation in the tropical Indian Ocean domain (30°E-110°E, 30°S-30°N). The SWR estimates are validated with an independent collocated data set and subsequently compared with the SWR estimates from the Global Energy and Water Cycle Experiment-Surface Radiation Budget V3.0 (GEWEX-SRB), International Satellite Cloud Climatology Project-Flux Data (ISCCP-FD), and National Centers for Environmental Prediction (NCEP) reanalysis for the year 2007. The present algorithm provides significantly better accuracy of SWR estimates, with a root-mean-square error of 27.3 W m-2 as compared with the values of 32.7, 37.5, and 59.6 W m-2 obtained from GEWEX-SRB, ISCCP-FD, and NCEP, respectively. The present algorithm also provides consistently better SWR compared with other available products under different sky conditions and seasons over Indian Ocean warm-pool regions.

Shahi, Naveen R.; Thapliyal, Pradeep K.; Sharma, Rashmi; Pal, Pradip K.; Sarkar, Abhijit

2011-09-01

293

Time and frequency comparisons in Europe by means of ECS 5 geostationary satellite  

Microsoft Academic Search

A time synchronization experiment between some European laboratories using the passive television method applied to the signals broadcasted by Eutelsat I-F5 telecommunication satellite was completed in 1990. The results obtained in the last period, when also range measurements from a Telespazio ground station were performed, are analyzed to evaluate the accuracy level of the time comparisons corrected for the effect

Franco Cordara; V. Pettiti; A. Cenci; M. Fermi; C. Sciarretta

1990-01-01

294

A Model for Calculating Desert Aerosol Turbidity over the Oceans from Geostationary Satellite Data  

Microsoft Academic Search

A technique has been developed to infer the optical thickness of Saharan dust from Synchronous Meteorological Satellite (SMS) brightness measurements at visible wavelengths. The scattering model consists of an air layer, a dust layer and a lower boundary of variable albedo. Single-scatter properties of the dust computed from Mie theory were the basis for calculations by plane-parallel theory of radiative

Carl C. Norton; Frederick R. Mosher; Barry Hinton; David W. Martin; David Santek; William Kuhlow

1980-01-01

295

Performance evaluation of scalable TCP and highspeed TCP over geostationary satellite links  

Microsoft Academic Search

In this paper we analyse the performance in a satellite environment of two recently proposed modifications to the TCP's congestion control algorithm, namely scalable TCP and highspeed TCP. These two protocols, originally designed for high-speed backbone links, appear to be major candidates for replacing in the next-generation Internet the current congestion control mechanism implemented by standard TCP. In this paper,

Giovanni Giambene; Daniele Miorandi

2005-01-01

296

Use of Geostationary Satellite Data to Force Land Surface Schemes within Atmospheric Mesoscale Models  

NASA Technical Reports Server (NTRS)

A technique has been developed for assimilating GOES-derived skin temperature tendencies and insolation into the surface energy budget equation of a mesoscale model so that the simulated rate of temperature change closely agrees with the satellite observations. A critical assumption of the technique is that the availability of moisture (either from the soil or vegetation) is the least known term in the model's surface energy budget. Therefore, the simulated latent heat flux, which is a function of surface moisture availability, is adjusted based upon differences between the modeled and satellite-observed skin temperature tendencies. An advantage of this technique is that satellite temperature tendencies are assimilated in an energetically consistent manner that avoids energy imbalances and surface stability problems that arise from direct assimilation of surface shelter temperatures. The fact that the rate of change of the satellite skin temperature is used rather than the absolute temperature means that sensor calibration is not as critical. The technique has been employed on a semi-operational basis at the GHCC within the PSU/NCAR MM5. Assimilation has been performed on a grid centered over the Southeastern US since November 1998. Results from the past year show that assimilation of the satellite data reduces both the bias and RMSE for simulations of surface air temperature and relative humidity. These findings are based on comparison of assimilation runs with a control using the simple 5-layer soil model available in MM5. A significant development in the past several months was the inclusion of the detailed Oregon State University land surface model (OSU/LSM) as an option within MM5. One of our working hypotheses has been that the assimilation technique, although simple, may provide better short-term forecasts than a detailed LSM that requires significant number initialized parameters. Preliminary results indicate that the assimilation out performs the OSU/LSM as it is incorporated in MM5. Details will be presented at the symposium.

Lapenta, William M.; Suggs, Ron; McNider, Richard T.; Jedlovec, Gary; Dembek, Scott R.; Goodman, H. Michael (Technical Monitor)

2000-01-01

297

On-orbit checkout study. [for the synchronous meteorological satellite and the technology demonstration satellite  

NASA Technical Reports Server (NTRS)

The spaceborne testing equipment carried by the orbiter and the measuring equipment onboard the satellite (telemetry) is tested to verify that each is operating satisfactorily. The satellite command system is also checked. Thermal stabilization with the satellite in the orbiter shadow is achieved in six to eight hours. Satellite subsystem tests are run, and thermal control by heaters is checked. Thermal stabilization with the satellite exposed to the sun (when the orbiter is in sunlight) is again achieved in an estimated six to eight hours. Subsystem tests are again run in the hot condition, and heat rejection tests are made.

Pritchard, E. I.

1977-01-01

298

Observation-based estimation of cloud-top height by geostationary satellite split-window measurements trained with CloudSat data  

NASA Astrophysics Data System (ADS)

Look-up table for estimating the cloud-top height of upper-tropospheric clouds by the infrared brightness temperature (TB) at 10.8 ?m (T11) and its difference from TB at 12 ?m (?T11-12) measured by a geostationary satellite are presented. The look-up table was constructed by regressing the cloud radar measurements by the CloudSat satellite over the infrared measurements by the Japanese geostationary satellite MTSAT-1R. Standard deviations of measurements around the estimates were also displayed as an indicator of the ambiguity in the estimates, and were less than 1 km for the upper-tropospheric clouds with T11 < 240 K. The dependences of the estimates of cloud-top height at each point in T11-?T11-12 space on latitude, season, satellite zenith angle, day-night, and land-sea differences were examined. It was shown that these dependences were considered as being uniform in tropics, except for the region with large satellite zenith angle. The presented look-up tables can provide hourly estimates of cloud-top height at a specified location, and are fairly useful in comparing them with ground-based observations such as vertical profiles of humidity and/or wind.

Hamada, Atsushi; Nishi, Noriyuki

2010-11-01

299

Development of a Cloud-Top Height Estimation Method by Geostationary Satellite Split-Window Measurements Trained with CloudSat Data  

NASA Astrophysics Data System (ADS)

Estimation of cloud-top height and visible optical thickness of upper-tropospheric clouds by brightness temperature (TB) measurements of geostationary satellite at two infrared split-window wavelengths was conducted. These cloud parameters were estimated by regressing the measurements of 94-GHz cloud radar onboard CloudSat satellite in terms of TB at 10.8 um (T11) and its difference from TB at 12 um (?T = T11 -T12) measured by geostationary satellite MTSAT-1R. Estimation by geostationary satellite measurements are fairly useful in field campaigns aiming mesoscale cloud systems, where cloud-top heights are compared with the vertical profiles of ground-based measurements such as wind and cloud condensates in a short time interval. Hamada et al. (2008) conducted the estimation of cloud-top height by T11 and ?T measured by GMS-5, using ship-borne cloud radar measurements. However, their ground-based result was limited to the non-rainy clouds, since cloud radar signal is heavily attenuated by precipitation particles. Spaceborne radar measurements enables an estimation of cloud-top height without concern for the existence of precipitation. We examined the dependences of the estimates of cloud-top height on latitude, season, satellite zenith angle, day-night, and land-sea differences. It was shown that these dependences were considered as being uniform in tropics, except for the region with large satellite zenith angle. The dependences on latitude and season were negligible in tropics, while they became the most significant factor affecting the estimates at higher latitudes. Estimation of visible optical thickness was also conducted, although limited to the non-rainy high clouds. The distributions of estimates in TB-?T space were qualitatively consistent with those expected from a simplified radiative transfer equation, although the standard deviations of measurements were slightly large. The near real-time products has already been provided on our Website (http://www-clim.kugi.kyoto-u.ac.jp/hamada/ctop/). Since the CloudSat conducts cloud radar observations on a global scale, the method adopted in this study can easily be applied to other current geostationary satellites with split-window channels, yielding hourly estimation map of cloud-top and optical thickness in global scale. We will show the results also using Meteosat Second Generation measurements.

Hamada, Atsushi; Nishi, Noriyuki; Inoue, Toshiro

2010-05-01

300

Thirteenth satellite of Jupiter. [orbit determination  

NASA Technical Reports Server (NTRS)

The discovery, observations, and attempts to determine the orbit of Jupiter XIII are described. It is found that the orbit is very similar to the orbits of Jupiter VI, VII, and X. An ephemeris is provided for the 1975 opposition.

Kowal, C. T.; Aksnes, K.; Marsden, B. G.; Roemer, E.

1975-01-01

301

GPS-Based Navigation and Orbit Determination for the AMSAT Phase 3D Satellite  

NASA Technical Reports Server (NTRS)

This paper summarizes the results of processing GPS data from the AMSAT Phase 3D (AP3) satellite for real-time navigation and post-processed orbit determination experiments. AP3 was launched into a geostationary transfer orbit (GTO) on November 16, 2000 from Kourou, French Guiana, and then was maneuvered into its HEO over the next several months. It carries two Trimble TANS Vector GPS receivers for signal reception at apogee and at perigee. Its spin stabilization mode currently makes it favorable to track GPS satellites from the backside of the constellation while at perigee, and to track GPS satellites from below while at perigee. To date, the experiment has demonstrated that it is feasible to use GPS for navigation and orbit determination in HEO, which will be of great benefit to planned and proposed missions that will utilize such orbits for science observations. It has also shown that there are many important operational considerations to take into account. For example, GPS signals can be tracked above the constellation at altitudes as high as 58000 km, but sufficient amplification of those weak signals is needed. Moreover, GPS receivers can track up to 4 GPS satellites at perigee while moving as fast as 9.8 km/sec, but unless the receiver can maintain lock on the signals long enough, point solutions will be difficult to generate. The spin stabilization of AP3, for example, appears to cause signal levels to fluctuate as other antennas on the satellite block the signals. As a result, its TANS Vectors have been unable to lock on to the GPS signals long enough to down load the broadcast ephemeris and then generate position and velocity solutions. AP3 is currently in its eclipse season, and thus most of the spacecraft subsystems have been powered off. In Spring 2002, they will again be powered up and AP3 will be placed into a three-axis stabilization mode. This will significantly enhance the likelihood that point solutions can be generated, and perhaps more important, that the receiver clock can be synchronized to GPS time. This is extremely important for real-time and post-processed orbit determination, where removal of receiver clock bias from the data time tags is needed, for time-tagging of science observations. Current analysis suggests that the inability to generate point solutions has allowed the TANS Vector clock bias to drift freely, being perhaps as large as 5-7 seconds by October, 2001, thus causing up to 50 km of along-track orbit error. The data collected in May, 2002 while in three-axis stabilized mode should provide a significant improvement in the orbit determination results.

Davis, George; Carpenter, Russell; Moreau, Michael; Bauer, Frank H.; Long, Anne; Kelbel, David; Martin, Thomas

2002-01-01

302

Earth System: Satellites  

NSDL National Science Digital Library

There are thousands of artificial satellites circling our planet for navigation, communications, entertainment, and science. These satellites are an integral part of our everyday life, and they collect data which cannot be obtained from Earth's surface. This video segment describes the basic components of a satellite and some of applications that have been developed for both geostationary and orbiting satellites. The segment is three minutes fifty seconds in length. A background essay and discussion questions are included.

303

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

304

Evaluation of Bulk Charging in Geostationary Transfer Orbit and Earth Escape Trajectories Using the Numit 1-D Charging Model  

NASA Technical Reports Server (NTRS)

The NUMIT 1-dimensional bulk charging model is used as a screening to ol for evaluating time-dependent bulk internal or deep dielectric) ch arging of dielectrics exposed to penetrating electron environments. T he code is modified to accept time dependent electron flux time serie s along satellite orbits for the electron environment inputs instead of using the static electron flux environment input originally used b y the code and widely adopted in bulk charging models. Application of the screening technique ts demonstrated for three cases of spacecraf t exposure within the Earth's radiation belts including a geostationa ry transfer orbit and an Earth-Moon transit trajectory for a range of orbit inclinations. Electric fields and charge densities are compute d for dielectric materials with varying electrical properties exposed to relativistic electron environments along the orbits. Our objectiv e is to demonstrate a preliminary application of the time-dependent e nvironments input to the NUMIT code for evaluating charging risks to exposed dielectrics used on spacecraft when exposed to the Earth's ra diation belts. The results demonstrate that the NUMIT electric field values in GTO orbits with multiple encounters with the Earth's radiat ion belts are consistent with previous studies of charging in GTO orb its and that potential threat conditions for electrostatic discharge exist on lunar transit trajectories depending on the electrical proper ties of the materials exposed to the radiation environment.

Minow, Joseph I.; Coffey, Victoria N.; Parker, Linda N.; Blackwell, William C., Jr.; Jun, Insoo; Garrett, Henry B.

2007-01-01

305

Geostationary microwave sounder requirements  

NASA Astrophysics Data System (ADS)

The National Oceanic and Atmospheric Administration (NOAA) is considering a microwave radiometer for the next series of Geostationary Operational Environmental Satellites (GOES-R) to be launched starting in 2012. This paper examines the products proposed for the geostationary microwave radiometer in the light of current microwave retrieval algorithms and estimates the performance achievable from geostationary altitude with a three-meter antenna. The results suggest that hemispheric soundings and rain rates can be generated on an hourly basis with the desired accuracy and horizontal resolution, that capping inversions can be detected in conjunction with infrared soundings, that hurricane warm core temperatures can be resolved using high frequencies plus deconvolution and that ocean wind and total precipitable water products can be provided with close to the desired resolution.

Chu, Donald; Grody, Norman C.; Madden, Michael; Susskind, Joel; Blackwell, William J.

2004-12-01

306

Quasi-real-time monitoring of SW radiation budget using geostationary satellite for Climate study and Renewable energy. (Invited)  

NASA Astrophysics Data System (ADS)

Solar radiation is the only source of energy that drives the weather and climate of the Earth's surface. Earth is warmed by incoming solar radiation, and emitted energy to space by terrestrial radiation due to its temperature. It has been kept to the organisms viable environment by the effect of heating and cooling. Clouds can cool the Earth by reflecting solar radiation and also can keep the Earth warm by absorbing and emitting terrestrial radiation. They are important in the energy balance at the Earth surface and the Top of the Atmosphere (TOA) and are connected complicatedly into the Earth system as well as other climate feedback processes. Thus it is important to estimate Earth's radiation budget for better understanding of climate and environmental change. We have shared several topics related to climate change. Energy issues close to the climate change, it is an environmental problems. Photovoltaics is one of the power generation method to converts from solar radiation to electric power directly. It does not emit greenhouse gases during power generation. Similarly, drainage, exhaust, vibration does not emit. PV system can be distributed as a small power supply in urban areas and it can installed to near the power demand points. Also solar thermal is heat generator with high efficiency. Therefor it is an effective energy source that the solar power is expected as one of the mitigation of climate change (IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation). It is necessary to real-time-monitoring of the surface solar radiation for safety operation of electric power system. We introduce a fusion analysis of renewable energy and Quasi-real-time analysis of SW radiation budget. Sample of estimated PV power mapping using geostationary satellite.

Takenaka, H.; Nakajima, T. Y.; Kuze, H.; Takamura, T.; Pinker, R. T.; Nakajima, T.

2013-12-01

307

The Role of Orograph and Parallax Corrections on High Resolution Geostationary Satellite Rainfall Estimates for Flash Flood Applications  

NASA Technical Reports Server (NTRS)

The current generation of geosynchronous satellites exhibits considerably improved capabilities in the area of resolution, gridding accuracy, and sampling frequency as compared to their predecessors. These improvements have made it possible to accurately observe the life cycle of small scale, short-live phenomenon like rapidly developing thunderstorms, at a very high spatial and temporal resolutions. While the gain in the improved resolution is not significant for synoptic scale cloud systems, it plays a major role on the computation of precipitation values for mesoscale and stonn scale systems. Two of the important factor on the accurate precision of precipitation from satellite imagery are the position of the cloud tops as viewed by the satellite and the influence of orographic effects on the distribution of precipitation. The first problem has to do with the fact that the accurate estimation of precipitation from data collected by a satellite in geosynchronous orbit requires the knowledge of the exact position of the cloud tops with respect to the ground below. This is not a problem when a cloud is located directly below the satellite; at large viewing angles the geographic coordinates on satellite images are dependent on cloud heights and distance from the sub-satellite point. The latitude and longitude coordinates for high convective cloud tops are displaced away from the sub-satellite point and may be shifted by as much as 20 Km from the sea level coordinates. The second problem has to do with the variations in rainfall distribution with elevation. Ground observations have shown that precipitation amounts tend to increase with height and that the slope of the hill or mountain that is facing the prevailing wind normally receives greater rainfall then do the lee slopes. The purpose of the study is to show the recent developments at the Office of Research and Applications (ORA) at the National Oceanic and Atmospheric Administration (NOAA/NESDIS) in Camp Springs, MD, USA, to adjust any satellite rainfall estimation technique and account for orographic and parallax corrections. Description and examples of the procedure applied to the current NOAA/NESDIS experimental satellite rainfall estimation technique for flash flood applications will be presented at the conference.

Vicente, Gilberto A.; Davenport, Clay; Scofield, Rod

1999-01-01

308

Prediction of relativistic electron flux at geostationary orbit following storms: Multiple regression analysis  

NASA Astrophysics Data System (ADS)

Many solar wind and magnetosphere parameters correlate with relativistic electron flux following storms. These include relativistic electron flux before the storm; seed electron flux; solar wind velocity and number density (and their variation); interplanetary magnetic field Bz, AE and Kp indices; and ultra low frequency (ULF) and very low frequency (VLF) wave power. However, as all these variables are intercorrelated, we use multiple regression analyses to determine which are the most predictive of flux when other variables are controlled. Using 219 storms (1992-2002), we obtained hourly averaged electron fluxes for outer radiation belt relativistic electrons (>1.5 MeV) and seed electrons (100 keV) from Los Alamos National Laboratory spacecraft (geosynchronous orbit). For each storm, we found the log10 maximum relativistic electron flux 48-120 h after the end of the main phase of each storm. Each predictor variable was averaged over the 12 h before the storm, the main phase, and the 48 h following minimum Dst. High levels of flux following storms are best modeled by a set of variables. In decreasing influence, ULF, seed electron flux, Vsw and its variation, and after-storm Bz were the most significant explanatory variables. Kp can be added to the model, but it adds no further explanatory power. Although we included ground-based VLF power from Halley, Antarctica, it shows little predictive ability. We produced predictive models using the coefficients from the regression models and assessed their effectiveness in predicting novel observations. The correlation between observed values and those predicted by these empirical models ranged from 0.645 to 0.795.

Simms, Laura E.; Pilipenko, Viacheslav; Engebretson, Mark J.; Reeves, Geoffrey D.; Smith, A. J.; Clilverd, Mark

2014-09-01

309

The effect of observation geometry on single-channel aerosol retrievals from geostationary satellites in the Mediterranean  

NASA Astrophysics Data System (ADS)

Satellite remote sensing is nowadays used for aerosol monitoring on an operational basis via specially designed algorithms which are based on multidimensional data. The development of sensors suitable for aerosol monitoring, has given way to the implementation of algorithms for multispectral (e.g. MODIS, MERIS and SEVIRI sensors), hyper-spectral (e.g. CHRIS sensor), multi-angle (e.g. MISR and CHRIS sensors) and multi-polarization observations (e.g. POLDER sensor) both over ocean and land. These sensors have been providing data on a continuous basis for less than two decades (e.g. MODIS archived aerosol data are available since 2001), a period which cannot be considered adequate for studies related to global climate change. On the other hand, archived data from the first generation meteorological sensors such as AVHRR and MVIRI (aboard the NOAA and METEOSAT series satellites respectively) span a period of almost thirty years a fact that is challenging as regards re-processing of such data. In the past, single channel algorithms developed for operational AOD retrievals over oceans have been successfully applied with METEOSAT data (Moulin et al. 1997) and are still used on an operational basis in several cases for AVHRR (Ignatov et al. 2004), SEVIRI (Bridley & Ignatov 2006) and MODIS (Ignatov et al. 2006).One of the main limitations of such algorithms affecting the accuracy of the AOD retrievals is the need for a universal aerosol model. Such an approach although have led to accurate results in open oceanic areas it can be problematic in more complex environments such as the Mediterranean where multiple types of aerosol particles (i.e. desert dust, pollution aerosol and oceanic particles) are encountered (Myhre et al. 2005). In the present paper the expected accuracy of a single channel algorithm developed for the visible MVIRI band is assessed as a function of the aerosol model and the geometry of observation of the geostationary METEOSAT satellite. Two different aerosol models are used as candidate models corresponding to desert dust and water soluble particles encountered in the Mediterranean region. The theoretical simulations were based on radiative transfer computations performed with the 6S code. Results showed that that optimum geometries can be defined where the AOD error is minimized. The results are confirmed using Meteosat-6 data along with concurrent AERONET measurements from the Mediterranean. References Brindley, H, and A. Ignatov, 2006: Retrieval of mineral aerosol optical depth and size information from Meteosat Second Generation solar reflectance bands, Remote Sens. Env., 102, 344-363. Ignatov, A., Sapper, J., Laszlo, I., Nalli, N., and K. Kidwell, 2004: Operational Aerosol Observations (AEROBS) from AVHRR/3 onboard NOAA-KLM satellites. J.Atm.Ocean.Tech., 21, 3-26. Ignatov, A., Minnis, P., Miller, W., Wielicki, B., and L.Remer, 2006: Consistency of global MODIS Aerosol Optical Depths over ocean on Terra and Aqua CERES SSF Datasets. J.Geophys.Res., 111, D14202. Moulin, C., Guillard, F. , Dulac, F. , and C. E. Lambert, 1997 : Long-term daily monitoring of Saharan dust load over ocean using Meteosat ISCCP-B2 data 1. Methodology and preliminary results for 1983-1994 in the Mediterranean, J. Geophys. Res., 102(D14), 16,947-16,958. Myhre, G., Stordal, F., Johnsrud, M., Diner, D.J., Geogdzhayev, I.V., Haywood, J.M., Holben, B., Holzer-Popp, T., Ignatov, A., Kahn, R., Kaufman, Y.J., Loeb, N., Martonshik, J., Mishchenko, M.I., Nalli, N.R., Remer, L.A., Schroedter- Homscheidt, M., Tanré, D., Torres, O. and Want, M., 2005: Intercomparison of satellite retrieved aerosol optical depth over ocean during the period September 1997 to December 2000, Atmos Chem and Phys, 5, 1697-1719.

Paronis, Dimitris; Hatzopoulos, John; Dulac, Francois

2010-05-01

310

The National Polar-orbiting Operational Environmental Satellite System  

Microsoft Academic Search

The tri-agency Integrated Program Office (IPO) is responsible for managing the development of the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS will replace the current military and civilian operational polar-orbiting ``weather'' satellites. The Northrop Grumman Space Technology - Raytheon team was competitively selected in 2002 as the Acquisition and Operations contractor team to develop, integrate, deploy, and operate NPOESS

H. Bloom

2004-01-01

311

The National Polar-orbiting Operational Environmental Satellite System  

Microsoft Academic Search

Over the last decade, the tri-agency Integrated Program Office (IPO), comprised of the National Oceanic and Atmospheric Administration (NOAA), the Department of Defense (DoD), and the National Aeronautics and Space Administration (NASA), has been managing the development of the National Polar-orbiting Operational Environmental Satellite System (NPOESS). Once operational later this decade, NPOESS will replace NOAA's Polar-orbiting Operational Environmental Satellites (POES)

C. W. Hoffman; S. Mango; S. Schneider; J. Duda; J. Haas; H. Bloom

2005-01-01

312

A mathematical simulation of earth satellite explosion debris orbital elements  

E-print Network

Nay 1970 Major Subject Nathematics A MATHEMATICAL SlmZATION OZ EARTH SATELLITE EXPLOSION DEBRIS ORBITAL ELEMENTS A Thesis WAI? EDWARD MABREY Approved as to style and content by: haxrman o ommi tee Head o epartment mber Member May 1.../70 ABSTRACT A Mathematical Simulation of Earth Satellite Explosion Debris Orbital Elements. (ifay lcI'70) Wayne Edward Plabrey, B. A. , Texas ARPI University Directed by: Professor J. T. Kent Assumed. explosive force vectors are transformed from a...

Mabrey, Wayne Edward

1970-01-01

313

Effects of the Satellite Power System on low Earth orbit and geosynchronous satellites  

Microsoft Academic Search

The large amount of power contained in the main beam and principal sidelobes of the proposed Solar Power System (SPS), now under study by DOE and NASA, potentially presents an EMC problem for other satellite systems. This report examines selected geosynchronous orbit (GEO) satellites in adjacent slots to an SPS, GEO satellites on a chord passing an Earth horizon, and

W. B. Grant; E. L. Morrison; J. R. Juroshek

1981-01-01

314

Satellite Imaging in the Study of Pennsylvania's Environmental Issues.  

ERIC Educational Resources Information Center

This document focuses on using satellite images from space in the classroom. There are two types of environmental satellites routinely broadcasting: (1) Polar-Orbiting Operational Environmental Satellites (POES), and (2) Geostationary Operational Environmental Satellites (GOES). Imaging and visualization techniques provide students with a better…

Nous, Albert P.

315

Operational retrieval of Asian sand and dust storm from FY-2C geostationary meteorological satellite and its application to real time forecast in Asia  

NASA Astrophysics Data System (ADS)

This paper describes an operational retrieval algorithm for the sand/dust storm (SDS) from FY-2C/S-VISSR (Stretched-Visible and Infrared Spin-Scan Radiometer) developed at the National Satellite Meteorological Center (NSMC) of China. This algorithm, called Dust Retrieval Algorithm based on Geostationary Imager (DRAGI), is based on the optical and radiative physical properties of SDS in mid-infrared and thermal infrared spectral regions as well as the observation of all bands in the geostationary imager, which include the Brightness Temperature Difference (BTD) in split window channels, Infrared Difference Dust Index (IDDI) and the ratio of middle infrared reflectance to visible reflectance. It also combines the visible and water vapor bands observation of the geostationary imager to identify the dust clouds from the surface targets and meteorological clouds. The output product is validated by and related to other dust aerosol observations such as the synoptic weather reports, surface visibility, aerosol optical depth (AOD) and ground-based PM10 observations. Using the SDS-IDD product and a data assimilation scheme, the dust forecast model CUACE/Dust achieved a substantial improvement to the SDS predictions in spring 2006.

Hu, X. Q.; Lu, N. M.; Niu, T.; Zhang, P.

2008-03-01

316

Operational retrieval of Asian sand and dust storm from FY-2C geostationary meteorological satellite and its application to real time forecast in Asia  

NASA Astrophysics Data System (ADS)

This paper describes an operational retrieval algorithm for the sand/dust storm (SDS) from FY-2C/S-VISSR (Stretched - Visible and Infrared Spin-Scan Radiometer) developed at the National Satellite Meteorological Center (NSMC) of China. This algorithm, called Dust Retrieval Algorithm based on Geostationary Imager (DRAGI), is based on the optical and radiative physical properties of SDS in mid-infrared and thermal infrared spectral regions as well as the observation of all bands in the geostationary imager, which include the Brightness Temperature Difference (BTD) in split window channels, Infrared Difference Dust Index (IDDI) and the ratio of middle infrared reflectance to visible reflectance. It also combines the visible and water vapor bands observation of the geostationary imager to identify the dust clouds from the surface targets and meteorological clouds. The output product is validated by and related to other dust aerosol observations such as the synoptic weather reports, surface visibility, aerosol optical depth (AOD) and ground-based PM10 observations. Using the SDS-IDDI data and a data assimilation scheme, the dust forecast model CUACE/Dust achieved a substantial improvement to the SDS predictions in spring 2006.

Hu, X. Q.; Lu, N. M.; Niu, T.; Zhang, P.

2007-06-01

317

Electric Propulsion for Low Earth Orbit Communication Satellites  

NASA Technical Reports Server (NTRS)

Electric propulsion was evaluated for orbit insertion, satellite positioning and de-orbit applications on big (hundreds of kilograms) and little (tens of kilograms) low earth orbit communication satellite constellations. A simple, constant circumferential thrusting method was used. This technique eliminates the complex guidance and control required when shading of the solar arrays must be considered. Power for propulsion was assumed to come from the existing payload power. Since the low masses of these satellites enable multiple spacecraft per launch, the ability to add spacecraft to a given launch was used as a figure of merit. When compared to chemical propulsion ammonia resistojets, ion, Hall, and pulsed plasma thrusters allowed an additional spacecraft per launch Typical orbit insertion and de-orbit times were found to range from a few days to a few months.

Oleson, Steven R.

1997-01-01

318

Method of resolving radio phase ambiguity in satellite orbit determination  

NASA Technical Reports Server (NTRS)

For satellite orbit determination, the most accurate observable available today is microwave radio phase, which can be differenced between observing stations and between satellites to cancel both transmitter- and receiver-related errors. For maximum accuracy, the integer cycle ambiguities of the doubly differenced observations must be resolved. To perform this ambiguity resolution, a bootstrapping strategy is proposed. This strategy requires the tracking stations to have a wide ranging progression of spacings. By conventional 'integrated Doppler' processing of the observations from the most widely spaced stations, the orbits are determined well enough to permit resolution of the ambiguities for the most closely spaced stations. The resolution of these ambiguities reduces the uncertainty of the orbit determination enough to enable ambiguity resolution for more widely spaced stations, which further reduces the orbital uncertainty. In a test of this strategy with six tracking stations, both the formal and the true errors of determining Global Positioning System satellite orbits were reduced by a factor of 2.

Councelman, Charles C., III; Abbot, Richard I.

1989-01-01

319

The Geostationary Fourier Transform Spectrometer  

NASA Technical Reports Server (NTRS)

The Geostationary Fourier Transform Spectrometer (GeoFTS) is an imaging spectrometer designed for a geostationary orbit (GEO) earth science mission to measure key atmospheric trace gases and process tracers related to climate change and human activity. GEO allows GeoFTS to continuously stare at a region of the earth for frequent sampling to capture the variability of biogenic fluxes and anthropogenic emissions from city to continental spatial scales and temporal scales from diurnal, synoptic, seasonal to interannual. The measurement strategy provides a process based understanding of the carbon cycle from contiguous maps of carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and chlorophyll fluorescence (CF) collected many times per day at high spatial resolution (2.7kmx2.7km at nadir). The CO2/CH4/CO/CF measurement suite in the near infrared spectral region provides the information needed to disentangle natural and anthropogenic contributions to atmospheric carbon concentrations and to minimize uncertainties in the flow of carbon between the atmosphere and surface. The half meter cube size GeoFTS instrument is based on a Michelson interferometer design that uses all high TRL components in a modular configuration to reduce complexity and cost. It is self-contained and as independent of the spacecraft as possible with simple spacecraft interfaces, making it ideal to be a "hosted" payload on a commercial communications satellite mission. The hosted payload approach for measuring the major carbon-containing gases in the atmosphere from the geostationary vantage point will affordably advance the scientific understating of carbon cycle processes and climate change.

Key, Richard; Sander, Stanley; Eldering, Annmarie; Blavier, Jean-Francois; Bekker, Dmitriy; Manatt, Ken; Rider, David; Wu, Yen-Hung

2012-01-01

320

The Geostationary Fourier Transform Spectrometer  

NASA Technical Reports Server (NTRS)

The Geostationary Fourier Transform Spectrometer (GeoFTS) is an imaging spectrometer designed for an earth science mission to measure key atmospheric trace gases and process tracers related to climate change and human activity. The GeoFTS instrument is a half meter cube size instrument designed to operate in geostationary orbit as a secondary "hosted" payload on a commercial geostationary satellite mission. The advantage of GEO is the ability to continuously stare at a region of the earth, enabling frequent sampling to capture the diurnal variability of biogenic fluxes and anthropogenic emissions from city to continental scales. The science goal is to obtain a process-based understanding of the carbon cycle from simultaneous high spatial resolution measurements of carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and chlorophyll fluorescence (CF) many times per day in the near infrared spectral region to capture their spatial and temporal variations on diurnal, synoptic, seasonal and interannual time scales. The GeoFTS instrument is based on a Michelson interferometer design with a number of advanced features incorporated. Two of the most important advanced features are the focal plane arrays and the optical path difference mechanism. A breadboard GeoFTS instrument has demonstrated functionality for simultaneous measurements in the visible and IR in the laboratory and subsequently in the field at the California Laboratory for Atmospheric Remote Sensing (CLARS) observatory on Mt. Wilson overlooking the Los Angeles basin. A GeoFTS engineering model instrument is being developed which will make simultaneous visible and IR measurements under space flight like environmental conditions (thermal-vacuum at 180 K). This will demonstrate critical instrument capabilities such as optical alignment stability, interferometer modulation efficiency, and high throughput FPA signal processing. This will reduce flight instrument development risk and show that the GeoFTS design is mature and flight ready.

Key, Richard; Sander, Stanley; Eldering, Annmarie; Miller, Charles; Frankenberg, Christian; Natra, Vijay; Rider, David; Blavier, Jean-Francois; Bekker, Dmitriy; Wu, Yen-Hung

2012-01-01

321

The Western Union Telegraph Company's satellite switched TDMA advanced Westar system  

Microsoft Academic Search

The satellite switched time division multiple access (TDMA) advanced Westar system is described. The planned geostationary configuration for the communication satellites will consist of three operational satellites and an in-orbit shared spare. The four satellites, to be launched in the 1980's, will be identical and will be capable of providing NASA's Tracking and Data Relay Satellite System (TDRSS) Service, advanced

P. Schneider

1978-01-01

322

Space shuttle earth orbital rendezvous targeting techniques for near circular target satellite orbits  

NASA Technical Reports Server (NTRS)

The targeting techniques are developed which are required to determine the guidance reference release time of the space shuttle navigation system, the orbital insertion targeting values, and a time line of orbital maneuvers. An extension is made for rendezvous with a target satellite in an elliptical orbit.

Deaton, A. W.

1972-01-01

323

The orbits of the Galilean satellites of Jupiter  

Microsoft Academic Search

The long period behavior of the orbits of the Galilean satellites computer programs were used to perform all the algebraic manipulations and series expansions necessary to describe the mutual interactions among the satellites. Analytical solutions and numerical integrations indicate that at least three different kinds of mean motion must be distinguished: (1) the observed mean motion; (2) the 'mean' mean

B. C. Brown

1976-01-01

324

Dual-Satellite Observations of VHF Lightning From GPS Orbit  

NASA Astrophysics Data System (ADS)

Over the last several years, the remote sensing of very high frequency (VHF) lightning emissions from both low-earth orbit and Global Positioning System (GPS) orbit has been demonstrated with the Fast On-Orbit Recording of Transient Events (FORTE) satellite and with an experimental VHF receiver aboard the SVN 54 GPS satellite. Analyses have shown that these systems are most sensitive to an impulsive type of in-cloud lightning that appears to be a good generic indicator of thunderstorm convective activity. As a consequence, satellite-based VHF receivers are now recognized as potential candidates for global lightning monitoring missions. With the recent launch of a second experimental VHF receiver aboard the SVN 56 GPS satellite, we now have the opportunity to characterize multi-satellite detection of VHF lightning from GPS orbit. This paper presents data from and analysis of simultaneous observations of VHF lightning events by the SVN 54 and SVN 56 VHF receivers. The dual-satellite observations are used to (1) characterize the expected performance parameters of a multi-satellite VHF global lightning detection system, (2) demonstrate two-satellite thunderstorm geolocation using an intersecting isochron technique and (3) determine a detection efficiency for impulsive in-cloud lightning as a function of zenith angle (radiation pattern).

Suszcynsky, D. M.; Pongratz, M. B.; Linford, J.; Jacobson, A. R.

2003-12-01

325

Method of resolving radio phase ambiguity in satellite orbit determination  

Microsoft Academic Search

For satellite orbit determination, the most accurate observable available today is microwave radio phase, which can be differenced between observing stations and between satellites to cancel both transmitter- and receiver-related errors. For maximum accuracy, the integer cycle ambiguities of the doubly differenced observations must be resolved. To perform this ambiguity resolution, a bootstrapping strategy is proposed. This strategy requires the

Charles C. Councelman III; Richard I. Abbot

1989-01-01

326

Attitude control of prolate satellites in transfer orbit  

Microsoft Academic Search

The stabilization is considered of spinning prolate satellites during a geosynchronous transfer orbit and in particular for satellites carrying a liquid fuel apogee boost motor. Two fundamentally different approaches were taken. The first concept is one which employs spin rates of less than 1 rpm with the aim of reducing the magnitude of the well known dynamic instability of a

C. Milburn; D. Smart; T. Morley; L. Virdee; J. K. Ratcliffe

1977-01-01

327

WARC and CCIR support for spectrum-orbit planning  

NASA Technical Reports Server (NTRS)

Papers prepared for the use of the U.S. delegation to the 1979 World Administrative Radio Conference; papers contributed to the National CCIR study groups on broadcasting satellites and spectrum-orbit utilization; responses to specific requests for technical analyses and evaluations; and papers presented at technical conferences on related topics are presented. Nonlinear optimization methods for finding optimum positions of satellites in the fixed satellite service; the effects of geography on the use of the geostationary orbit; intercontinental orbit sharing; traffic coordination in interfering satellites operating in the fixed satellite service; and domestic fixed and broadcasting satellite systems are covered. A possible channel orbit plan for broadcasting satellite service in the U.S. and Canada; polarization for broadcasting satellite systems; and the communication capacity of the geostationary satellite orbit are also examined.

Sawitz, P. H.

1980-01-01

328

A Numerical Testbed for Remote Sensing of Aerosols, and its Demonstration for Evaluating Retrieval Synergy from a Geostationary Satellite Constellation of GEO-CAPE and GOES-R  

NASA Technical Reports Server (NTRS)

We present a numerical testbed for remote sensing of aerosols, together with a demonstration for evaluating retrieval synergy from a geostationary satellite constellation. The testbed combines inverse (optimal-estimation) software with a forward model containing linearized code for computing particle scattering (for both spherical and non-spherical particles), a kernel-based (land and ocean) surface bi-directional reflectance facility, and a linearized radiative transfer model for polarized radiance. Calculation of gas absorption spectra uses the HITRAN (HIgh-resolution TRANsmission molecular absorption) database of spectroscopic line parameters and other trace species cross-sections. The outputs of the testbed include not only the Stokes 4-vector elements and their sensitivities (Jacobians) with respect to the aerosol single scattering and physical parameters (such as size and shape parameters, refractive index, and plume height), but also DFS (Degree of Freedom for Signal) values for retrieval of these parameters. This testbed can be used as a tool to provide an objective assessment of aerosol information content that can be retrieved for any constellation of (planned or real) satellite sensors and for any combination of algorithm design factors (in terms of wavelengths, viewing angles, radiance and/or polarization to be measured or used). We summarize the components of the testbed, including the derivation and validation of analytical formulae for Jacobian calculations. Benchmark calculations from the forward model are documented. In the context of NASA's Decadal Survey Mission GEOCAPE (GEOstationary Coastal and Air Pollution Events), we demonstrate the use of the testbed to conduct a feasibility study of using polarization measurements in and around the O2 A band for the retrieval of aerosol height information from space, as well as an to assess potential improvement in the retrieval of aerosol fine and coarse mode aerosol optical depth (AOD) through the synergic use of two future geostationary satellites, GOES-R (Geostationary Operational Environmental Satellite R-series) and TEMPO (Tropospheric Emissions: Monitoring of Pollution). Strong synergy between GEOS-R and TEMPO are found especially in their characterization of surface bi-directional reflectance, and thereby, can potentially improve the AOD retrieval to the accuracy required by GEO-CAPE.

Wang, Jun; Xu, Xiaoguang; Ding, Shouguo; Zeng, Jing; Spurr, Robert; Liu, Xiong; Chance, Kelly; Mishchenko, Michael I.

2014-01-01

329

A numerical testbed for remote sensing of aerosols, and its demonstration for evaluating retrieval synergy from a geostationary satellite constellation of GEO-CAPE and GOES-R  

NASA Astrophysics Data System (ADS)

We present a numerical testbed for remote sensing of aerosols, together with a demonstration for evaluating retrieval synergy from a geostationary satellite constellation. The testbed combines inverse (optimal-estimation) software with a forward model containing linearized code for computing particle scattering (for both spherical and non-spherical particles), a kernel-based (land and ocean) surface bi-directional reflectance facility, and a linearized radiative transfer model for polarized radiance. Calculation of gas absorption spectra uses the HITRAN (HIgh-resolution TRANsmission molecular absorption) database of spectroscopic line parameters and other trace species cross-sections. The outputs of the testbed include not only the Stokes 4-vector elements and their sensitivities (Jacobians) with respect to the aerosol single scattering and physical parameters (such as size and shape parameters, refractive index, and plume height), but also DFS (Degree of Freedom for Signal) values for retrieval of these parameters. This testbed can be used as a tool to provide an objective assessment of aerosol information content that can be retrieved for any constellation of (planned or real) satellite sensors and for any combination of algorithm design factors (in terms of wavelengths, viewing angles, radiance and/or polarization to be measured or used). We summarize the components of the testbed, including the derivation and validation of analytical formulae for Jacobian calculations. Benchmark calculations from the forward model are documented. In the context of NASAs Decadal Survey Mission GEO-CAPE (GEOstationary Coastal and Air Pollution Events), we demonstrate the use of the testbed to conduct a feasibility study of using polarization measurements in and around the O2A band for the retrieval of aerosol height information from space, as well as an to assess potential improvement in the retrieval of aerosol fine and coarse mode aerosol optical depth (AOD) through the synergic use of two future geostationary satellites, GOES-R (Geostationary Operational Environmental Satellite R-series) and TEMPO (Tropospheric Emissions: Monitoring of Pollution). Strong synergy between GEOS-R and TEMPO are found especially in their characterization of surface bi-directional reflectance, and thereby, can potentially improve the AOD retrieval to the accuracy required by GEO-CAPE.

Wang, Jun; Xu, Xiaoguang; Ding, Shouguo; Zeng, Jing; Spurr, Robert; Liu, Xiong; Chance, Kelly; Mishchenko, Michael

2014-10-01

330

NOAA satellite programs and technology requirements  

NASA Technical Reports Server (NTRS)

Information concerning NOAA satellite programs is presented in vugraph form. The following topics are discussed: NOAA's space philosophy, the NESDIS FY-93 budget summary, LANDSAT program status, a history of geostationary satellites, the GOES program, current GOES instruments, improved GOES capabilities, polar orbiters, a history of TIROS R&D satellites, a history of ESSA operational satellites, a history of ITOS/NOAA satellites, and a history of TIROS-N/NOAA satellites.

Schneider, Stanley R.

1992-01-01

331

DRAG COEFFICIENT ESTIMATION USING SATELLITE ATTITUDE AND ORBIT DATA  

E-print Network

PENNSTATE _ DRAG COEFFICIENT ESTIMATION USING SATELLITE ATTITUDE AND ORBIT DATA 2Lt. Christopher L, December 13, 2013 12:00 - noon Presentation will be at the Swift MOC (CATO Park). Please RSVP to ratz12 of drag using orbital data gathered from NASA's Swift spacecraft. In order to accomplish this task

Maroncelli, Mark

332

Long range orbital error estimation for applications satellites  

NASA Technical Reports Server (NTRS)

A method of optimum orbital averaging was employed to study the long range accuracy potential of polar orbiting applications satellites. This approach involved the determination of the boundary conditions of one set of differential equations of motion by adjusting the initial conditions in a least square sense with the use of data generated by another set of differential equations of motion.

Bonavito, N. L.; Foreman, J. C.

1978-01-01

333

G-MG Satellite  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: A satellite orbiting the earth uses radar to communicate with two control stations on the earth's surface. The satellite is in a geostationary orbit. T...

334

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

NASA Astrophysics Data System (ADS)

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

Parks, Lisa Ann

335

Detection and orbit determination of tethered satellite systems  

NASA Astrophysics Data System (ADS)

A systematic algorithm for determining which satellites are tether-connected is described. It is assumed that observations in the forms of range, azimuth and elevation data, for several satellites, including singles, two-satellite tethered systems, and three-satellite tethered systems are available. The detection process is performed using the dynamic model and a minimum variance batch filter to process simulated observations over a period of ten minutes. In the process, the estimated acceleration per unit length between pairs of satellites due to a tether is assumed to be constant during this "short arc" observation period. The values of acceleration per unit length are used as indicators of which pairs of satellites are connected. Use of the algorithm is illustrated by applying it to a set of nine satellites that includes two tethered pairs. For small librational motion of the tethered pairs, values of the constraint accelerations per unit length that are large relative to zero were obtained. On the other hand, values very close to zero were obtained for un-tethered pairs. These results indicate that non-librating, two-satellite tethered systems can be successfully identified (i.e. "detected") when perfect and small-level noise corrupted observations are available. However, identification of two-satellite tethered systems with the large libration angle, or those with a very short tether when medium and large levels of noise are present is more difficult. The detection of a three-satellite tethered system was also performed with the same algorithm. After detection of a two-satellite tethered system (or three-satellite) is performed, its orbit may be determined by using long arcs of observations (over one orbital period). In the long arc estimation process used herein, the constraint acceleration per unit length is considered to be a time-varying variable. For an exemplary set of satellites, results for long arc estimations were obtained. Since observation data for both satellites in a tethered system were used and few approximations of the tether dynamics were made, the results are very accurate. The orbital motion of the three-satellite tether system was found to be similar to that of two-satellite tether system when the librational motion was small. The major difference was that larger tether accelerations were present due to another tether connected body. It should be relatively easy to incorporate the new method for detection and motion determination developed in this study into a general orbit determination process. (Abstract shortened by UMI.)

Choe, Nammi Jo

336

A method for the orbit determination accuracy improvement of a station with a limited motion antenna  

Microsoft Academic Search

A station with limited motion antenna is usually used for the on-orbit control of a geostationary satellite. In order to enhance the capability of running a satellite, it is important to improve the orbit determination accuracy of the singlestation system. This paper presents a method for the orbit determination accuracy improvement with tracking and ranging data from a single station.

Fenglei Wu; Jingyong Liu; Yongqing Liu; Yanning Li; Ping Zhu; Liming Du

2009-01-01

337

CASTOR: Cathode/Anode Satellite Thruster for Orbital Repositioning  

NASA Technical Reports Server (NTRS)

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

Mruphy, Gloria A.

2010-01-01

338

EUROPE'S GEOSTATIONARY METEOROLOGICAL SATELLITES  

E-print Network

MISSIONS MFG MISSION MSG MISSION MTG IMAGING MISSION MTG I MTG SOUNDING MISSION MTG S * MSG 4/METEOSAT 11 MTG S 1 MTG S 2 METEOSAT 9 MSG 3/METEOSAT 10 MSG 4/METEOSAT 11* METEOSAT FIRST GENERATION METEOSAT services over Europe and Africa, are now exclusively provided by Meteosat Second Generation (MSG

Stoffelen, Ad

339

Rotation Rates of Inactive Satellites Near Geosynchronous Earth Orbit  

NASA Astrophysics Data System (ADS)

Stabilized satellites in geosynchronous earth orbit (GEO) become drifters after they are decommissioned. In addition, each satellite begins to tumble or process in its inactive state. As they drift around the earth, the inactive satellites provide sequential viewing opportunities---with synodic periods of months or weeks---for observation with an earth-based sensor. In order to measure their rotation rates as a function of time, we track a set of inactive satellites over several months as each comes into view over Hawaii. Images of each satellite are acquired through a small (0.4-m) optical telescope system with sampling periods of a few seconds. With temporal light curves obtained through relative, in-frame photometry on each image, we analyze both the time and frequency domains in order to determine the satellites rotation rates.

Cognion, R.

2014-09-01

340

Autonomous Orbit Determination between a Lunar Satellite and a Distant Retrograde Orbit Probe  

NASA Astrophysics Data System (ADS)

Currently, orbit determination of lunar satellites heavily rely on ground stations on the Earth. The observation data suffers from problems such as low accuracy and bad visibility. An efficient way to release the burden of the ground stations and to enhance the observation accuracy is to use the inter-satellite range data between two lunar satellites. However, a well-known problem of only using this type of data is the overall rotation of the orbital plane (undetermined orbit inclination, ascending nod and perigee). Some external reference sources should be introduced into the system to avoid the overall rotation. Recently, an interesting idea is to use a probe around the Earth-Moon CLP (collinear libration point) as the reference source. The orbit of the CLP probe is unknown a priori. It is determined simultaneously with the lunar satellite’s orbit by using the inter-satellite range data between them. There are many advantages of this idea, but also some problems. One main problem is caused by the strong instability of the motions around the CLPs. Probes usually need a frequent orbit control, but the accuracy of the orbit determination of the CLP probes from a short arc between two maneuvers is usually unsatisfied. In this contribution, another kind of special probe other than the CLP probe is considered. It lies on a DRO (distant retrograde orbit) around the Moon. The DROs usually have much better stability property than the CLP orbits, so DRO probes don’t need a frequent orbit control. At the same time, our studies show that the OD accuracy is comparable to that of the CLP probe. The work is firstly done in the CRTBP (circular restricted three-body problem) model, by studying the OD results of different amplitude (both in plane and out of plane) for the DROs. Then, the study is generated to the real force model of the Earth-Moon system.

Hou, Xiyun; Tang, Jingshi; Liu, Lin; Liu, Peng

341

Satellite orbit determination - A first-hand experience with the first Brazilian satellite SCD1  

NASA Astrophysics Data System (ADS)

Under the Complete Brazilian Space Mission (MECB) project, the first Brazilian satellite SCDI was lofted on February 9, 1993 by a Pegasus rocket. This weather data collecting satellite was injected into a near-circular orbit of approximately 760 km altitude with an orbital inclination of 25 deg. The European Space Agency (ESA) kindly agreed to use their ground station facilities at Mas Palomas, Spain, to give tracking assistance to Brazil in the very first orbit of the satellite. However due to the failure of the clock in the launch vehicle, the Flight Mechanics group of INPE, Brazil, responsible for the flight dynamics software preparation and operation, had a great difficulty in determining the orbit at the injection point. This paper describes the difficulties faced by the group during that early phase, which critical decisions which had to be taken, how the hurdles were overcome, and how a very quick and good early orbit determination was achieved using the minimum data available.

Kuga, Helio K.; Kondapalli, Rama R.

1993-10-01

342

Near-optimal geostationary transfer maneuvers with cooperative en-route inspection using hybrid optimal control  

NASA Astrophysics Data System (ADS)

This research investigates the performance of bi-level hybrid optimal control algorithms in the solution of minimum delta-velocity geostationary transfer maneuvers with cooperative en-route inspection. The maneuvers, introduced here for the first time, are designed to populate a geostationary constellation of space situational awareness satellites while providing additional characterization of objects in lower-altitude orbit regimes. The maneuvering satellite, called the chaser, performs a transfer from low Earth orbit to geostationary orbit, during which it performs an inspection of one of several orbiting targets in conjunction with a ground site for the duration of the target's line-of-site contact with that site. A three-target scenario is used to test the performance of multiple bi-level hybrid optimal control algorithms. A bi-level hybrid algorithm is then utilized to solve fifteen-, and thirty-target scenarios and shown to have increasing benefit to complete enumeration as the number of targets is increased. Results indicate that the en-route inspection can be accomplished for a small increase in the delta-velocity required for a simple transfer to geostationary orbit given the same initial conditions.

Showalter, Daniel J.; Black, Jonathan T.

2014-12-01

343

The accuracy of orbit estimation for the low-orbit satellites LARETS and WESTPAC  

Microsoft Academic Search

The LARETS satellite was launched on September 26, 2004, into a circular orbit at an altitude of 690 km and with an inclination of 98.2°. This mission is a successor to the WESTPAC satellite which was launched to an altitude of 835 km six years before. The study is based on the observations taken by the global network of laser

Milena Rutkowska

2005-01-01

344

Cassini orbit determination performance during the first eight orbits of the Saturn satellite tour  

NASA Technical Reports Server (NTRS)

From June 2004 through July 2005, the Cassini/Huygens spacecraft has executed nine successful close-targeted encounters by three major satellites of the Saturnian system. Current results show that orbit determination has met design requirements for targeting encounters, Hugens descent, and predicting science instrument pointing for targetd satellite encounters. This paper compares actual target dispersion against, the predicte tour covariance analyses.

Antreasian, P. G.; Bordi, J. J.; Criddle, K. E.; Ionasescu, R.; Jacobson, R. A.; Jones, J. B.; MacKenzie, R. A.; Meek, M. C.; Pelletier, F. J.; Roth, D. C.; Roundhill, I. M.; Stauch, J.

2005-01-01

345

Numerical orbit generators of artificial earth satellites  

NASA Astrophysics Data System (ADS)

A numerical orbit integrator containing updatings and improvements relative to the previous ones that are being utilized by the Departmento de Mecanica Espacial e Controle (DMC), of INPE, besides incorporating newer modellings resulting from the skill acquired along the time is presented. Flexibility and modularity were taken into account in order to allow future extensions and modifications. Characteristics of numerical accuracy, processing quickness, memory saving as well as utilization aspects were also considered. User's handbook, whole program listing and qualitative analysis of accuracy, processing time and orbit perturbation effects were included as well.

Kugar, H. K.; Dasilva, W. C. C.

1984-04-01

346

An autonomous orbit determination method for MEO and LEO satellite  

NASA Astrophysics Data System (ADS)

A reliable and secure navigation system and assured autonomous capability of satellite are in high demand in case of emergencies in space. This paper introduces a novel autonomous orbit determination method for Middle-Earth-Orbit and Low-Earth-Orbit (MEO and LEO) satellite by observing space objects whose orbits are known. Generally, the geodetic satellites, such as LAGEOS and ETALONS, can be selected as the space objects here. The precision CCD camera on tracking gimbal can make a series of photos of the objects and surrounding stars when MEO and LEO satellite encounters the space objects. Then the information processor processes images and attains sightings and angular observations of space objects. Several clusters of such angular observations are incorporated into a batch least squares filter to obtain an orbit determination solution. This paper describes basic principle and builds integrated mathematical model. The accuracy of this method is analyzed by means of computer simulation. Then a simulant experiment system is built, and the experimental results demonstrate the feasibility and effectiveness of this method. The experimental results show that this method can attain the accuracy of 150 meters with angular observations of 1 arcsecond system error.

Zhang, Hui; Wang, Jin; Yu, Guobin; Zhong, Jie; Lin, Ling

2014-09-01

347

Orbits design for LEO space based solar power satellite system  

NASA Astrophysics Data System (ADS)

Space Based Solar Power satellites use solar arrays to generate clean, green, and renewable electricity in space and transmit it to earth via microwave, radiowave or laser beams to corresponding receivers (ground stations). These traditionally are large structures orbiting around earth at the geo-synchronous altitude. This thesis introduces a new architecture for a Space Based Solar Power satellite constellation. The proposed concept reduces the high cost involved in the construction of the space satellite and in the multiple launches to the geo-synchronous altitude. The proposed concept is a constellation of Low Earth Orbit satellites that are smaller in size than the conventional system. 7For this application a Repeated Sun-Synchronous Track Circular Orbit is considered (RSSTO). In these orbits, the spacecraft re-visits the same locations on earth periodically every given desired number of days with the line of nodes of the spacecraft's orbit fixed relative to the Sun. A wide range of solutions are studied, and, in this thesis, a two-orbit constellation design is chosen and simulated. The number of satellites is chosen based on the electric power demands in a given set of global cities. The orbits of the satellites are designed such that their ground tracks visit a maximum number of ground stations during the revisit period. In the simulation, the locations of the ground stations are chosen close to big cities, in USA and worldwide, so that the space power constellation beams down power directly to locations of high electric power demands. The j2 perturbations are included in the mathematical model used in orbit design. The Coverage time of each spacecraft over a ground site and the gap time between two consecutive spacecrafts visiting a ground site are simulated in order to evaluate the coverage continuity of the proposed solar power constellation. It has been observed from simulations that there always periods in which s spacecraft does not communicate with any ground station. For this reason, it is suggested that each satellite in the constellation be equipped with power storage components so that it can store power for later transmission. This thesis presents a method for designing the solar power constellation orbits such that the number of ground stations visited during the given revisit period is maximized. This leads to maximizing the power transmission to ground stations.

Addanki, Neelima Krishna Murthy

2011-12-01

348

Orbit determination with the tracking data relay satellite system  

NASA Technical Reports Server (NTRS)

The possibility of employing the tracking data relay satellite system to satisfy the orbit determination demands of future applications missions is investigated. It is shown that when the relay satellites are continuously and independently tracked from ground stations it is possible, using six hour data arcs, to recover user satellite state with an average error of about 25 m radially, 260 m along track, and 20 m cross track. For this arc length, range sum data and range sum rate data are equally useful in determining orbits. For shorter arc lengths (20 min), range sum rate data is more useful than range sum data. When relay satellites are not continuously tracked, user satellite state can be recovered with an average error of about 140 m radially, 515 m along track, and 110 m cross track. These results indicate that the TDRS system can be employed to satisfy the orbit determination demands of applications missions, such as the MAGSAT and potential gradiometer missions, provided the relay satellites are continuously and independently tracked.

Argentiero, P.; Loveless, F.

1977-01-01

349

Mapping Daily Evapotranspiration at Field to Global Scales using Geostationary and Polar Orbiting Satellite Imagery  

Technology Transfer Automated Retrieval System (TEKTRAN)

Thermal infrared (TIR) remote sensing of land-surface temperature (LST) provides valuable information about the sub-surface moisture status required for estimating evapotranspiration (ET) and detecting the onset and severity of drought. While empirical indices measuring anomalies in LST and vegetati...

350

On-Orbit Calibration of Satellite Gyroscopes  

NASA Technical Reports Server (NTRS)

In order to maneuver satellites accurately from one attitude to another, onboard rate sensing gyroscopes usually must be calibrated after launch. Several algorithms have been used to determine gyro biases, misalignments, and scale factors. This paper describes algorithms that have been used in the past, discusses their advantages and limitations, and describes a new algorithm and the gyro calibration results obtained using this new algorithm. The new algorithm has significant operational advantages in addition to being at least as accurate as other algorithms.

Hashmall, Joseph A.; Radomski, Mark; Sedlak, Joseph; Harman, Richard (Technical Monitor)

2000-01-01

351

Satellite probes plasma processes in earth orbit  

NASA Astrophysics Data System (ADS)

The mission of the DOD/NASA Combined Release and Radiation Effects Satellite (CRRES) is to deepen understanding of the earth's near-space environment, including the radiation belts and the ionosphere; this will help spacecraft designers protect against radiation-belt particles that affect onboard electronics, solar panel arrays, and crewmembers. Attention is presently given to CRRES's study of ionospheric plasma processes through releases of Ba, Ca, Sr, and Li at altitudes of 400-36,000 km.

Christensen, Andrew B.; Reasoner, David L.

1992-01-01

352

History of On-orbit Satellite Fragmentations (14th Edition)  

NASA Technical Reports Server (NTRS)

Since the first serious satellite fragmentation occurred in June 1961 (which instantaneously increased the total Earth satellite population by more than 400%) the issue of space operations within the finite region of space around the Earth has been the subject of increasing interest and concern. The prolific satellite fragmentations of the 1970s and the marked increase in the number of fragmentations in the 1980s served to widen international research into the characteristics and consequences of such events. Continued events in all orbits in later years make definition and historical accounting of those events crucial to future research. Large, manned space stations and the growing number of operational robotic satellites demand a better understanding of the hazards of the dynamic Earth satellite population.

Johnson, Nicholas L.; Stansbery, Eugene; Whitlock, David O.; Abercromby, Kira J.; Shoots, Debra

2008-01-01

353

In-Space Transportation for GEO Space Solar Power Satellites  

NASA Technical Reports Server (NTRS)

This report summarizes results of study tasks to evaluate design options for in-space transportation of geostationary Space Solar Power Satellites. Referring to the end-to-end architecture studies performed in 1988, this current activity focuses on transportation of Sun Tower satellite segments from an initial low Earth orbit altitude to a final position in geostationary orbit (GEO; i.e., 35,786 km altitude, circular, equatorial orbit). This report encompasses study activity for In-Space Transportation of GEO Space Solar Power (SSP) Satellites including: 1) assessment of requirements, 2) design of system concepts, 3) comparison of alternative system options, and 4) assessment of potential derivatives.

Martin, James A.; Donnahue, Benjamin B.; Henley, Mark W.

1999-01-01

354

Experiment of Autonomous Orbit Control on the DEMETER Satellite  

Microsoft Academic Search

An in-flight demonstration of Autonomous Orbit Control (AOC) will be carried out in 2004\\/2005 on the French micro-satellite DEMETER. The experiment aims at computing and performing station keeping maneuvers on board and autonomously. It is based on a TOPSTAR 3000 GPS receiver including the \\

A. Lamy; M.-C. Charmeau; D. Laurichess; M. Grondin; R. Bertrand

2004-01-01

355

Improving satellite vulnerability assessment to untrackable orbital debris  

NASA Astrophysics Data System (ADS)

The projected growth in the untrackable orbital debris population will place an increased emphasis on satellite vulnerability assessments during both design and mission operations. This study presents an enhanced method for assessing satellite vulnerability to untrackable orbital debris that expands on traditional practices. By looking beyond structural penetration of the spacecraft, the method predicts the survivability of individual components and the associated degradation of system functionality resulting from untrackable debris impacts. A new risk assessment tool, the Particle Impact Risk and Vulnerability Assessment Tool (PIRAT), has been developed based on this method and is also presented here. It interfaces with both the NASA ORDEM2000 and ESA MASTER-2009 debris models and has been validated against the benchmark test cases from the Inter-Agency Space Debris Coordination Committee (IADC). This study concludes with an example vulnerability assessment using PIRAT for a generic Earth observation satellite in a Sun-synchronous low-Earth orbit. The results illustrate the additional insight provided by this method that can be used to improve the robustness of future satellite designs and mitigate the overall mission risk posed by untrackable orbital debris.

Welty, Nathan; Schaefer, Frank; Rudolph, Martin; Destefanis, Roberto; Grassi, Lilith

2012-07-01

356

Low earth orbit satellite based communication systems — Research opportunities  

Microsoft Academic Search

Telecommunication systems are undergoing revolutionary changes that are transforming society, changing the way in which industrial and service organizations operate, and are having a profound effect on the daily life of individuals. Low earth orbit satellite (LEOS) based communication systems are a new and exciting endeavor in reshaping the global communication network and the services that it provides. Huge investments

Bezalel Gavish

1997-01-01

357

Orbital radiation exposure of the Astronomical Netherlands Satellite (ANS)  

NASA Technical Reports Server (NTRS)

The orbital electron and proton flux calculations were performed for determining the applicability of COS/MOS ciruits for the ANS computer and X-ray experiment logic. The results for electrons, protons, and the total lifetime the satellite spends in flux-free regions are presented in tables and graphs.

Stassinopoulos, E. G.

1971-01-01

358

Refined model for the evolution of distant satellite orbits  

NASA Astrophysics Data System (ADS)

We consider a model that describes the evolution of distant satellite orbits and that refines the solution of the doubly averaged Hill problem. Generally speaking, such a refinement was performed previously by J. Kovalevsky and A.A. Orlov in terms of Zeipel’s method by constructing a solution of the third order with respect to the small parameter m, the ratio of the mean motions of the planet and the satellite. The analytical solution suggested here differs from the solutions obtained by these authors and is closest in form to the general solution of the doubly averaged problem (˜ m 2). We have performed a qualitative analysis of the evolutionary equations and conditions for the intersection of satellite orbits with the surface of a spherical planet with a finite radius. Using the suggested solution, we have obtained improved analytical time dependences of the elements of evolving orbits for a number of distant satellites of giant planets compared to the solution of the doubly averaged Hill problem and, thus, achieved their better agreement with the results of our numerical integration of the rigorous equations of perturbed motion for satellites.

Vashkov'yak, M. A.; Teslenko, N. M.

2009-12-01

359

An Earth Orbiting Satellite Service and Repair Facility  

NASA Technical Reports Server (NTRS)

A conceptual design was produced for the Geosynchronous Satellite Servicing Platform (GSSP), an orbital facility capable of repairing and servicing satellites in geosynchronous orbit. The GSSP is a man-tended platform, which consists of a habitation module, operations module, service bay and truss assembly. This design review includes an analysis of life support systems, thermal and power requirements, robotic and automated systems, control methods and navigation, and communications systems. The GSSP will utilize existing technology available at the time of construction, focusing mainly on modifying and integrating existing systems. The entire facility, along with two satellite retrieval vehicles (SRV), will be placed in geosynchronous orbit by the Advanced Launch System. The SRV will be used to ferry satellites to and from the GSSP. Technicians will be transferred from Earth to the GSSP and back in an Apollo-derived Crew Transfer Capsule (CTC). These missions will use advanced telerobotic equipment to inspect and service satellites. Four of these missions are tentatively scheduled per year. At this rate, the GSSP will service over 650 satelites during the projected 25 year lifespan.

Berndt, Andrew; Cardoza, Mike; Chen, John; Daley, Gunter; Frizzell, Andy; Linton, Richard; Rast, Wayne

1989-01-01

360

Benefits Derived From Laser Ranging Measurements for Orbit Determination of the GPS Satellite Orbit  

NASA Technical Reports Server (NTRS)

While navigation systems for the determination of the orbit of the Global Position System (GPS) have proven to be very effective, the current research is examining methods to lower the error in the GPS satellite ephemerides below their current level. Two GPS satellites that are currently in orbit carry retro-reflectors onboard. One notion to reduce the error in the satellite ephemerides is to utilize the retro-reflectors via laser ranging measurements taken from multiple Earth ground stations. Analysis has been performed to determine the level of reduction in the semi-major axis covariance of the GPS satellites, when laser ranging measurements are supplemented to the radiometric station keeping, which the satellites undergo. Six ground tracking systems are studied to estimate the performance of the satellite. The first system is the baseline current system approach which provides pseudo-range and integrated Doppler measurements from six ground stations. The remaining five ground tracking systems utilize all measurements from the current system and laser ranging measurements from the additional ground stations utilized within those systems. Station locations for the additional ground sites were taken from a listing of laser ranging ground stations from the International Laser Ranging Service. Results show reductions in state covariance estimates when utilizing laser ranging measurements to solve for the satellite s position component of the state vector. Results also show dependency on the number of ground stations providing laser ranging measurements, orientation of the satellite to the ground stations, and the initial covariance of the satellite's state vector.

Welch, Bryan W.

2007-01-01

361

Observations of orbital debris and satellites in Slovak Republic  

NASA Astrophysics Data System (ADS)

There are many accidental optically tracked artificial objects during observations at Astronom-ical and Geophysical Observatory FMPI CU, Modra, Slovak Republic (AGO). Those objects are usually orbital debris or satellites. A tool to identify such a type of objects was necessary to create. Our software is called SatEph and is used to identify tracked artificial objects and to compute their orbital elements. SatEph is based on analytic propagation model SGP4 and TLE data. Program is still under development and in the near future it will be a part of software for automated search telescope for small near Earth asteroids at AGO. We present orbital debris observation simulation for the new optical searching system. Unlike other aster-oids searching systems (Catalina Sky Survey, LINEAR, Spacewatch etc.) our system should be capable to detect small asteroids in close vicinity of the Earth (smaller then Lunar distance) with high angular speed. The limiting magnitude of observable objects is about +16 magnitude and the pixel scale is 4,6 arcsec/px. This allows us to detect man made objects as well. We studied how many satellites and orbital debris with known orbital elements are able to track per given observing night. We also studied frequency detection of tracked object during one night. The searching system field of view will be 4.4 x 4.4 square degrees and the system will search more then 2000 square degrees per night. Exposure time for every single CCD shot is set to 30 seconds. We found out, there is possible to track from 250 to 450 objects (mostly with geosynchronous orbits) per one night in dependence on given day of the year. More then 200 objects have at least 3 astrometric positions per one night, which can be useful for orbit determination process. The tracked objects are mostly satellites and rocket bodies, which have different orbits, from low Earth orbit to geosynchronous Earth orbit. Data of orbital debris astrometric positions will be offered for national space agencies and used for our own orbit determination. Those data could be useful for orbital elements updating of catalogue, or non catalogue artificial objects.

Silha, Jiri; Toth, Juraj

362

Quasi-satellite Orbits in the Context of Coorbital Dynamics  

NASA Astrophysics Data System (ADS)

Abstract (2,250 Maximum Characters): The investigations on long-term evolution of asteroid’s orbits are crucial to understanding the route through which the present configuration of the Solar system came to be. The so-called coorbiting asteroids (which share their orbits with major planets) attract the special attention in this connection: are they the primordial remnants of the building blocks of the corresponding major planet or are they the "migrants" from the other parts of the Solar system? The most well known examples of co-orbits in natural objects are provided by Trojan groups of asteroids and by asteroids moving in horseshoe orbits. These asteroids are precluded from having relatively close encounters with their host planets. However, there exists another class of coorbiting objects in which the opposite is true: they remain very near to the host planet eternally or, at least, for long enough time. Since typically they never enter the planet’s Hill sphere, they cannot be considered as satellites in the usual sense of the word. In order to emphasize this specific they are called quasi-satellites (QS). We explore the properties of QS-orbits under the scope of the restricted spatial circular three-body problem. Via double numerical averaging, we construct evolutionary equations which describe the long-term behaviour of the orbital elements of an asteroid. Special attention is paid at possible transitions between the motion in a QS-orbit and that in another type of orbit available in the 1:1 mean motion resonance. To illustrate the typical rates of the orbital elements's secular evolution, the dynamics of the near-Earth asteroid 2004GU9 was studied. This asteroid will keep describing a QS-orbit for the next several hundreds of years. This work was supported by the grant of the Russian Academy of Sciences Presidium Program 22: "Fundamental problems of research and exploration of the Solar system".

Sidorenko, Vladislav; Artemyev, A.; Neishtadt, A.; Zelenyi, L.

2013-05-01

363

Mt. St. Helens eruption as observed by satellite and estimates of its impact on the planetary radiation budget  

Microsoft Academic Search

A study was conducted of the eruption of Mt. St. Helens' on May 18, 1980, taking into account both geostationary and polar orbiting satellite data. The geostationary data made it possible to determine the expansion rates and the growth of the plume from shortly after the explosion to several days afterwards. An investigation of the equivalent blackbody temperature provided an

A. Gruber; A. Krueger; W. Shen; M. Matson

1981-01-01

364

On-Orbit Calibration of a Multi-Spectral Satellite Satellite Sensor Using a High Altitude Airborne Imaging Spectrometer  

NASA Technical Reports Server (NTRS)

Earth-looking satellites must be calibrated in order to quantitatively measure and monitor components of land, water and atmosphere of the Earth system. The inevitable change in performance due to the stress of satellite launch requires that the calibration of a satellite sensor be established and validated on-orbit. A new approach to on-orbit satellite sensor calibration has been developed using the flight of a high altitude calibrated airborne imaging spectrometer below a multi-spectral satellite sensor.

Green, R. O.; Shimada, M.

1996-01-01

365

Measurement of total electron content of midlatitude ionosphere and protonosphere via Faraday rotation and group relay techniques using transmission from geostationary satellites ATS-3 and ATS-6  

NASA Technical Reports Server (NTRS)

Measurement of integrated columnar electron content and total electron content for the local ionosphere and the overlying protonosphere via Faraday rotation and group delay techniques has proven very useful. A field station was established having the geographic location of 31.5 deg N latitude and 91.06 deg W longitude to accomplish these objectives. A polarimeter receiving system was set up in the beginning to measure the Faraday rotation of 137.35 MHz radio signal from geostationary satellite ATS 3 to yield the integrated columnar electron content of the local ionosphere. The measurement was continued regularly, and the analysis of the data thus collected provided a synopsis of the statistical variation of the ionosphere along with the transient variations that occurred during the periods of geomagnetic and other disturbances.

Paul, M. P.

1982-01-01

366

Evaluation of Temperature and Material Combinations on Several Lubricants for Use in the Geostationary Operational Environmental Satellite (GOES) Mission Filter Wheel Bearings  

NASA Technical Reports Server (NTRS)

A bearing test apparatus was used to investigate lubricant degradation rates and elastohydrodynamic transition temperatures for several perfluoropolyether (Krytox) formulations, a pentasilahydrocarbon, and a synthetic hydrocarbon (Pennzane 2001 A) in an MPB 1219 bearing, which is used in the geostationary operational environmental satellite (GOES) mission filter wheel assembly. Test conditions were the following: 1000-hr duration, 75 C, 20 lb axial load, vacuum level less than 1 x 10(exp -6) Torr, and a 600-rpm rotational speed. Baseline tests were performed using unformulated Krytox 143AB, the heritage lubricant. Krytox additive formulations showed small reductions in degradation rate. Krytox GPL-105, a higher viscosity version, yielded the least amount of degradation products. Both the silahydrocarbon and Pennzane 2001A showed no signs of lubricant degradation and had ample amounts of free oil at test conclusion.

Jansen, Mark J.; Jones, William R., Jr.; Predmore, Roamer E.

2001-01-01

367

Satellite Motion Effects on Current Collection in Low Earth Orbit  

NASA Technical Reports Server (NTRS)

Results from the Tethered Satellite System (TSS) missions unambiguously show that the electrodynamic tether system produced 2 to 3 times the predicted current levels in the tether. The pre-mission predictions were based on the well-known Parker-Murphy (PM) model, which describes the collection of current by an electrically biased satellite in the ionospheric plasma. How the TSS satellite was able to collect 2-3 times the PM current has remained an open question. In the present study, self-consistent potential and motional effects are introduced into the Thompson and Dobrowolny sheath models. As a result, the magnetic field aligned sheath-an essential variable in determining current collection by a satellite-is derived and is shown to be explicitly velocity dependent. The orientation of the satellite's orbital motion relative to the geomagnetic field is also considered in the derivation and a velocity dependent expression for the collected current is obtained. The resulting model provides a realistic treatment of current collection by a satellite in low earth orbit. Moreover, the predictions, using the appropriate parameters for TSS, are in good agreement with the tether currents measured during the TSS-1R mission.

Zhang, T. X.; Hwang, K. S.; Wu, S. T.; Stone, N. H.; Chang, C. L.; Drobot, A.; Wright, K. H., Jr.; Rose, M. Franklin (Technical Monitor)

2000-01-01

368

Orbital simulations of satellite escape/capture and the origin of satellites such as Triton  

NASA Technical Reports Server (NTRS)

We investigate satellite escape/capture in the context of the restricted, circular three body problem as applied to the Sun, Neptune, and Triton. We have computed a large number of coplanar prograde and retrograde orbital simulations over a range of initial distances and velocities. The satellite starts at superior conjunction within approximately 2 Hill radii of Neptune and has a velocity orthogonal to the Sun-planet line. Orbits with these initial conditions can be reflected with respect to time, so an escape is simply the reverse of a capture. We numerically integrate the equations of motion to compute the satellite's position until it escapes, collides with Neptune, or after 100 planetary years fails to escape, when computations cease. The initial distance x and velocity v in the restricted problem uniquely define the Jacobi constant C, a conserved energy-like quantity. Plots of the simulation outcomes in the prograde and retrograde C, x phase spaces reveal distinct zones in which temporary satellites approach the planet closely enough that permanent capture can be effected by gas drag with a protoplanetary nebula or by collision with a pre-existing satellite. Single and double close-flybys constitute the most common possible capture orbits. Long term multiple flyby orbits occur near the stability limits between bound and unbound orbits, and are more common among retrograde captures.

Benner, Lance A. M.; Mckinnon, William B.

1993-01-01

369

NASA Now: Orbital Mechanics: Earth Observing Satellites - Duration: 6:03.  

NASA Video Gallery

This NASA Now program is all about satellites and their orbits. Dr. James Gleason, project scientist for NPP, explains what it takes for a satellite to stay in orbit, why there are different types ...

370

Use of elliptical orbits for a Ka-band personal access satellite system  

NASA Technical Reports Server (NTRS)

The use of satellites in elliptical orbits for a Ka-band personal communications system application designed to provide voice and data service within the continental U.S. is examined. The impact of these orbits on system parameters such as signal carrier-to-noise ratio, roundtrip delay, Doppler shift, and satellite antenna size is quantized for satellites in two elliptical orbits, the Molniya and the ACE orbits. The number of satellites necessary for continuous CONUS coverage has been determined for the satellites in these orbits. The increased system complexity brought about by the use of satellites at such altitudes is discussed.

Motamedi, Masoud; Estabrook, Polly

1990-01-01

371

Control System and Flexible Satellite Interaction During Orbit Transfer Maneuver  

NASA Technical Reports Server (NTRS)

In this paper the interaction between the attitude control system and the flexible structure of an artificial satellite during orbit transfer maneuver has been investigated. The satellite was modeled by a rigid central body with one or more flexible appendages. The dynamics equations were obtained by Lagrangean approach. The flexible appendages were treated as clamped-free beam and its displacement was discretized by assumed- mode method. In order to transfer the satellite, a typical Hohmann transfer and a burn-coast-burn strategy were used and the attitude was controlled by an on-off controller. During transfer procedure a global analysis of satellite has been done, such as: performance of control system, influence of elastic response in control system, thruster firing frequency, fuel consumption and variation of orbital elements. In order to avoid the interaction with structure motion, a control system with bandwidth of one decade bellow the fundamental frequency was used. In the simulations the firing frequency was evaluated in an approximately way but kept below the fundamental frequency of the structure. The control system has kept the attitude below the specifications. As a result, the orbit transfer maneuvering has been done correctly without excessive excitation of flexible appendage.

daSilva, Adenilson Roberto; GadelhadeSouza, Luiz Carlos

1998-01-01

372

ORBITAL AND COLLISIONAL EVOLUTION OF THE IRREGULAR SATELLITES David Nesvorny,1  

E-print Network

ORBITAL AND COLLISIONAL EVOLUTION OF THE IRREGULAR SATELLITES David Nesvorny´,1 Jose L. A satellites, the irregular moons revolve around planets at large distances in tilted and eccentric orbits. Here we report a study of the orbital and collisional evolution of the irregular satellites from times

Nesvorny, David

373

Control of satellite clusters in elliptic orbit with limited communication.  

PubMed

The cooperative control of satellite clusters in elliptical, low-Earth orbit is studied, with the goal of minimizing the necessary information passed among the individual satellites in the cluster. We investigate two possible control paradigms in this paper. The system is described using linearized equations of motion, allowing it to be expressed as a time-varying linear system. The control objective is to attain a required formation at a specified point along the orbit. A decentralized controller is used, in which each satellite maintains a local estimate of the overall state of the cluster. These estimates, along with any control information, are shared after any satellite executes a control action. The second paradigm is an extension of the first, in which state estimates are never shared, and only the control information is passed. In each case, less information being passed results in a higher computational burden on each satellite. Simulation results show cyclic errors, likely induced by higher-order terms in eccentricity and inclinations. The controller that shares state estimates performs much better than the controller that passes only control information. PMID:15220147

Chichka, David F; Belanger, Gene; Speyer, Jason L

2004-05-01

374

Analysis of Satellite and Sub-Orbital Measurements  

NASA Technical Reports Server (NTRS)

The objective of this project is to support the INTEX aircraft mission by developing experience in the integrated analysis of existing sub-orbital observations and satellite observations with numerical models. Specific tasks include providing guidance to INTEX by identifying discrepancies in satellite observations with (1) in situ measurements, (2) bottom-up emission inventories of nitrogen oxides and volatile organic compounds, and (3) model calculations of the export of pollution from North America to the global atmosphere. An important focus area is developing and improving bottom-up emission inventories by combining top-down and bottom-up information.

Gleason, James (Technical Monitor); Martin, Randall V.

2004-01-01

375

On-board orbit determination for applications satellites  

NASA Technical Reports Server (NTRS)

An algorithm for satellite orbit determination is described which would be suitable for use with an on-board computer with limited core storage. The proposed filter is recursive on a pass-by-pass basis and features a fading memory to account for the effect of gravity field error. Only a single pass of Doppler data needs to be stored at any time and the data may be acquired from two reference beacons located within the Continental United States. The results of both simulated data and real data reductions demonstrate that the satellite's position can be determined to within one kilometer when a 4 x 4 recovery field is used.

Morduch, G. E.; Lefler, J. G.; Argentiero, P. D.; Garza-Robles, R.

1978-01-01

376

Space environment measurements by JAXA satellites and ISS/JEM  

NASA Astrophysics Data System (ADS)

In order to monitor space environment and its temporal variations, JAXA Space Environment Group has been developing space radiation detectors as well as magnetometers and installing them on Low Earth Orbit (LEO) satellites, Geostationary Orbit (GEO) satellites, Geostationary Transfer Orbit (GTO) satellite, Quasi Zenith Orbit (QZO) satellite and Japanese Experimental Module (JEM) of the International Space Station (ISS). We are using these space environment data to know the situation of space environment and to provide warning messages to the satellite operators as well as ISS/JEM manager, when the space environment will be harmful. Based on our observation data, we also have constructed an advanced electron belt model for the use in satellite manufacturing. With space radiation data obtained by JAXA satellites and ISS, some findings related to the space radiation environment have been obtained. We will review our activities related to the space environment research and development in JAXA.

Obara, Takahiro; Matsumoto, Haruhisa; Koga, Kiyokazu

2012-02-01

377

Shuttle orbiter - IUS/DSP satellite interface contamination study  

NASA Technical Reports Server (NTRS)

The results of a contamination analysis on the Defense Support Program (DSP) satellite during launch and deployment by the Space Transportation System (STS) are presented. Predicted contaminant deposition was also included on critical DSP surfaces during the period soon after launch when the DSP is in the shuttle orbiter bay with the doors closed, the bay doors open, and during initial deployment. Additionally, a six sided box was placed at the spacecraft position to obtain directional contaminant flux information for a general payload while in the bay and during deployment. The analysis included contamination sources from the shuttle orbiter, IUS and cradle, the DSP sensor and the DSP support package.

Rantanen, R. O.; Strange, D. A.

1978-01-01

378

Modeling radiation forces acting on satellites for precision orbit determination  

NASA Astrophysics Data System (ADS)

Models of the TOPEX/Poseidon spacecraft are developed by means of finite-element analyses for use in generating acceleration histories for various orbit orientations which account for nonconservative radiation forces. The acceleration profiles are developed with an analysis based on the use of the 'box-wing' model in which the satellite is modeled as a combination of flat plates. The models account for the effects of solar, earth-albedo, earth-IR, and spacecraft-thermal radiation. The finite-element analysis gives the total force and induced accelerations acting on the satellite. The plate types used in the analysis have parameters that can be adjusted to optimize model performance according to the micromodel analysis and tracking observations. Acceleration related to solar radiation pressure is modeled effectively, and the techniques are shown to be useful for the precise orbit determinations required for spacecraft such as the TOPEX/Poseidon.

Marshall, J. A.; Antreasian, P. G.; Rosborough, G. W.; Putney, B. H.

1992-08-01

379

Modeling radiation forces acting on satellites for precision orbit determination  

NASA Technical Reports Server (NTRS)

Models of the TOPEX/Poseidon spacecraft are developed by means of finite-element analyses for use in generating acceleration histories for various orbit orientations which account for nonconservative radiation forces. The acceleration profiles are developed with an analysis based on the use of the 'box-wing' model in which the satellite is modeled as a combination of flat plates. The models account for the effects of solar, earth-albedo, earth-IR, and spacecraft-thermal radiation. The finite-element analysis gives the total force and induced accelerations acting on the satellite. The plate types used in the analysis have parameters that can be adjusted to optimize model performance according to the micromodel analysis and tracking observations. Acceleration related to solar radiation pressure is modeled effectively, and the techniques are shown to be useful for the precise orbit determinations required for spacecraft such as the TOPEX/Poseidon.

Marshall, J. A.; Antreasian, P. G.; Rosborough, G. W.; Putney, B. H.

1992-01-01

380

Orbital Perturbations of the Galilean Satellites during Planetary Encounters  

NASA Astrophysics Data System (ADS)

The Nice model of the dynamical instability and migration of the giant planets can explain many properties of the present solar system, and can be used to constrain its early architecture. In the jumping-Jupiter version of the Nice model, required from the terrestrial planet constraint and dynamical structure of the asteroid belt, Jupiter has encounters with an ice giant. Here, we study the survival of the Galilean satellites in the jumping-Jupiter model. This is an important concern because the ice-giant encounters, if deep enough, could dynamically perturb the orbits of the Galilean satellites and lead to implausible results. We performed numerical integrations where we tracked the effect of planetary encounters on the Galilean moons. We considered three instability cases from Nesvorný & Morbidelli that differed in the number and distribution of encounters. We found that in one case, where the number of close encounters was relatively small, the Galilean satellite orbits were not significantly affected. In the other two, the orbital eccentricities of all moons were excited by encounters, Callisto's semimajor axis changed, and, in a large fraction of trials, the Laplace resonance of the inner three moons was disrupted. The subsequent evolution by tides damps eccentricities and can recapture the moons in the Laplace resonance. A more important constraint is represented by the orbital inclinations of the moons, which can be excited during the encounters and not appreciably damped by tides. We find that one instability case taken from Nesvorný & Morbidelli clearly does not meet this constraint. This shows how the regular satellites of Jupiter can be used to set limits on the properties of encounters in the jumping-Jupiter model, and help us to better understand how the early solar system evolved.

Deienno, Rogerio; Nesvorný, David; Vokrouhlický, David; Yokoyama, Tadashi

2014-08-01

381

A retrospective analysis of the Shinmoedake (Japan) eruption of 26-27 January 2011 by means of Japanese geostationary satellite data  

NASA Astrophysics Data System (ADS)

During the sub-plinian eruptions of Mt. Shinmoedake (Japan) on 26-27 January 2011 a significant amount of ash was emitted into the atmosphere, destroying thousands of hectares of farm land, causing air traffic disruption, and forcing the closure of four railroad lines located around the volcano. In this work, a retrospective analysis of these eruptive events is presented, exploiting the high temporal resolution of the Japanese Multi-functional Transport Satellites (MTSAT) data to study thermal volcanic activity, to identify and track volcanic ash, and to determine the cloud-top height, inferring information about eruption features and space-time evolution. We show that a strong and sudden increase in the thermal signal occurred at Mt. Shinmoedake as a consequence of above mentioned eruptive events, generating hot spots timely detected by the RSTVOLC algorithm for the first time implemented here on data provided by geostationary satellites. This study also shows that the emitted ash plume, identified by means of the RSTASH algorithm, strongly fluctuated in altitude, reaching a maximum height around 7.4 km above sea level, in agreement with information provided by the Tokyo VAAC. The plume heights derived in this work, by implementing the widely accepted cloud-top temperature method, appear also compatible with the values provided by independent weather radar measurements, with the main differences characterizing the third sub-plinian event that occurred in the afternoon of 27 January. The estimates of discharge rate, the temporal trend of ash affected areas, and the results of thermal monitoring reported in this work seem to indicate that the third sub-plinian event was the least intense. In spite of some limitations, this study confirms the potential of Japanese geostationary satellites in effectively monitoring volcanoes located in the West Pacific region, providing continuous information also about such critical parameters of ash clouds as the plume height. Such information is useful not only for driving numerical models, forecasting ash dispersion into the atmosphere, but also for characterizing eruption features and dynamics.

Marchese, F.; Falconieri, A.; Pergola, N.; Tramutoli, V.

2014-01-01

382

Tracking target objects orbiting earth using satellite-based telescopes  

DOEpatents

A system for tracking objects that are in earth orbit via a constellation or network of satellites having imaging devices is provided. An object tracking system includes a ground controller and, for each satellite in the constellation, an onboard controller. The ground controller receives ephemeris information for a target object and directs that ephemeris information be transmitted to the satellites. Each onboard controller receives ephemeris information for a target object, collects images of the target object based on the expected location of the target object at an expected time, identifies actual locations of the target object from the collected images, and identifies a next expected location at a next expected time based on the identified actual locations of the target object. The onboard controller processes the collected image to identify the actual location of the target object and transmits the actual location information to the ground controller.

De Vries, Willem H; Olivier, Scot S; Pertica, Alexander J

2014-10-14

383

Spatially resolving methane emissions in California: constraints from the CalNex aircraft campaign and from present (GOSAT, TES) and future (TROPOMI, geostationary) satellite observations  

NASA Astrophysics Data System (ADS)

We apply a continental-scale inverse modeling system for North America based on the GEOS-Chem model to optimize California methane emissions at 1/2° × 2/3° horizontal resolution using atmospheric observations from the CalNex aircraft campaign (May-June 2010) and from satellites. Inversion of the CalNex data yields a best estimate for total California methane emissions of 2.86 ± 0.21 Tg a-1, compared with 1.92 Tg a-1 in the EDGAR v4.2 emission inventory used as a priori and 1.51 Tg a-1 in the California Air Resources Board (CARB) inventory used for state regulations of greenhouse gas emissions. These results are consistent with a previous Lagrangian inversion of the CalNex data. Our inversion provides 12 independent pieces of information to constrain the geographical distribution of emissions within California. Attribution to individual source types indicates dominant contributions to emissions from landfills/wastewater (1.1 Tg a-1), livestock (0.87 Tg a-1), and gas/oil (0.64 Tg a-1). EDGAR v4.2 underestimates emissions from livestock, while CARB underestimates emissions from landfills/wastewater and gas/oil. Current satellite observations from GOSAT can constrain methane emissions in the Los Angeles Basin but are too sparse to constrain emissions quantitatively elsewhere in California (they can still be qualitatively useful to diagnose inventory biases). Los Angeles Basin emissions derived from CalNex and GOSAT inversions are 0.42 ± 0.08 and 0.31 ± 0.08 Tg a-1 that the future TROPOMI satellite instrument (2015 launch) will be able to constrain California methane emissions at a detail comparable to the CalNex aircraft campaign. Geostationary satellite observations offer even greater potential for constraining methane emissions in the future.

Wecht, K. J.; Jacob, D. J.; Sulprizio, M. P.; Santoni, G. W.; Wofsy, S. C.; Parker, R.; Bösch, H.; Worden, J.

2014-08-01

384

Satellite power system LEO vs GEO assembly issues. [construction in Low Earth Orbits vs GEosynchronous Orbits  

NASA Technical Reports Server (NTRS)

A strawman crystal-silicon 5-GW Satellite Power System (SPS) concept formed the basis of a study of construction concepts for building a complete SPS in low earth orbit (LEO) or geosynchronous orbit (GEO). Construction scenarios were evolved, including factory-in-space concepts and operations. Design implications imposed on the SPS satellite as a consequence of in-orbit assembly operations, and related attitude control requirements during assembly in LEO or GEO environments, were also evaluated. Results are presented indicating that complete assembly of an operational SPS in LEO, followed by transport to GEO, does not appear technically desirable. The best mix, however, of LEO versus GEO construction activity remains to be resolved.

Mockovciak, J., Jr.; Adornato, R. J.

1977-01-01

385

47 CFR 25.146 - Licensing and operating rules for the non-geostationary satellite orbit Fixed-Satellite Service...  

Code of Federal Regulations, 2013 CFR

...power flux-density, in the space-to-Earth direction, (EPFD down ) limits ...flux-density (PFD) masks, on the surface of the Earth, for each space station in the NGSO...power flux-density, in the space-to-Earth direction, (additional operational...

2013-10-01

386

An Intensive Research of Satellite Orbit Theory and Application in Orbit Determination, Forecast and Parameter Estimation  

NASA Astrophysics Data System (ADS)

It has been over half a century since the launch of the first artificial satellite Sputnik in 1957, which marks the beginning of the Space Age. During the past 50 years, with the development and innovations in various fields and technologies, satellite application has grown more and more intensive and extensive. This thesis is based on three major research projects which the author joined in. These representative projects cover main aspects of satellite orbit theory and application of precise orbit determination (POD), and also show major research methods and important applications in orbit dynamics. Chapter 1 is an in-depth research on analytical theory of satellite orbits. This research utilizes general transformation theory to acquire high-order analytical solutions when mean-element method is not applicable. These solutions can be used in guidance and control or rapid orbit forecast within the accuracy of 10-6. We also discuss other major perturbations, each of which is considered with improved models, in pursuit of both convenience and accuracy especially when old models are hardly applicable. Chapter 2 is POD research based on observations. Assuming a priori force model and estimation algorithm have reached their accuracy limits, we introduce empirical forces to Shenzhou-type orbit in order to compensate possible unmodeled or mismodeled perturbations. Residuals are analyzed first and only empirical force models with actual physical background are considered. This not only enhances a posteriori POD accuracy, but also considerably improves the accuracy of orbit forecast. This chapter also contains theoretical discussions on modeling of empirical forces, computation of partial derivatives and propagation of various errors. Error propagation helps to better evaluate orbital accuracy in future missions. Chapter 3 is an application of POD in space geodesy. GRACE satellites are used to obtain Antarctic temporal gravity field between 2004 and 2007. Various changes from traditional methods are implemented to better represent the regional temporal gravity field in this work. As a thesis in astrodynamics, this chapter will concentrate on orbit problems and estimation approaches. Although most details in geophysics are skipped, gravity field solutions will be displayed and the preliminary images of Antarctic mass flux will be revealed. These researches are summarized but not concluded in this thesis. Many problems have been left in all the aspects mentioned in this thesis and need to be studied in future researches, not to mention that the fast developing space technology keeps redefining our traditional knowledge with new concepts and elements. So future work and directions will be discussed at the end of the thesis, expecting further progress upon the present achievements.

Tang, J. S.

2011-03-01

387

47 CFR 25.259 - Time sharing between NOAA meteorological satellite systems and non-voice, non-geostationary...  

Code of Federal Regulations, 2014 CFR

...satellite is the area on the Earth's surface in which the...satellite is the area on the Earth's surface in which the...must establish a 24-hour per day contact person and telephone...harmful interference into NOAA earth stations and other...

2014-10-01

388

47 CFR 25.259 - Time sharing between NOAA meteorological satellite systems and non-voice, non-geostationary...  

Code of Federal Regulations, 2013 CFR

...satellite is the area on the Earth's surface in which the...satellite is the area on the Earth's surface in which the...shall establish a 24-hour per day contact person and telephone...harmful interference into NOAA earth station users and...

2013-10-01

389

Transport Protocol and Resource Management for Satellite Networks: Framework of a Project  

E-print Network

of a satellite communications system. The protocol stack is based on the TCP/IP suite adapted to the channel proposed in the paper is mainly targeted to GEO (Geostationary Orbit) satellite communication systemsTransport Protocol and Resource Management for Satellite Networks: Framework of a Project Davide

Rossi, Michele

390

X-, Ku- and Ka-band compact feed horns for global-Earth coverage from a geostationary orbit  

Microsoft Academic Search

Three compact global-Earth coverage horns have been designed to meet specifications similar to those required for the Optus C1 satellite. These horns have high gain, low sidelobes, good return loss and have compact geometries

C. Granet; T. S. Bird

2000-01-01

391

Geostationary platform systems concepts definition study. Volume 1: Executive summary  

NASA Technical Reports Server (NTRS)

The results of a geostationary platform concept analysis are summarized. Mission and payloads definition, concept selection, the requirements of an experimental platform, supporting research and technology, and the Space Transportation System interface requirements are addressed. It is concluded that platforms represent a logical extension of current trends toward larger, more complex, multifrequency satellites. Geostationary platforms offer significant cost savings compared to individual satellites, with the majority of these economies being realized with single Shuttle launched platforms. Further cost savings can be realized, however, by having larger platforms. Platforms accommodating communications equipment that operates at multiple frequencies and which provide larger scale frequency reuse through the use of large aperture multibeam antennas and onboard switching maximize the useful capacity of the orbital arc and frequency spectrum. Projections of market demand indicate that such conservation measures are clearly essential if orderly growth is to be provided for. In addition, it is pointed out that a NASA experimental platform is required to demonstrate the technologies necessary for operational geostationary platforms of the 1990's.

1980-01-01

392

Contrast in low-cost operational concepts for orbiting satellites  

NASA Astrophysics Data System (ADS)

Older spacecraft missions, especially those in low Earth orbit with telemetry intensive requirements, required round-the-clock control center staffing. The state of technology relied on control center personnel to continually examine data, make decisions, resolve anomalies, and file reports. Hubble Space Telescope (HST) is a prime example of this description. Technological advancements in hardware and software over the last decade have yielded increases in productivity and operational efficiency, which result in lower cost. The re-engineering effort of HST, which has recently concluded, utilized emerging technology to reduce cost and increase productivity. New missions, of which NASA's Transition Region and Coronal Explorer Satellite (TRACE) is an example, have benefited from recent technological advancements and are more cost-effective than when HST was first launched. During its launch (1998) and early orbit phase, the TRACE Flight Operations Team (FOT) employed continually staffed operations. Yet once the mission entered its nominal phase, the FOT reduced their staffing to standard weekday business hours. Operations were still conducted at night and during the weekends, but these operations occurred autonomously without compromising their high standards for data collections. For the HST, which launched in 1990, reduced cost operations will employ a different operational concept, when the spacecraft enters its low-cost phase after its final servicing mission in 2004. Primarily due to the spacecraft"s design, the HST Project has determined that single-shift operations will introduce unacceptable risks for the amount of dollars saved. More importantly, significant cost-savings can still be achieved by changing the operational concept for the FOT, while still maintaining round-the-clock staffing. It"s important to note that the low-cost solutions obtained for one satellite may not be applicable for other satellites. This paper will contrast the differences between low-cost operational concepts for a satellite launched in 1998 versus a satellite launched in 1990.

Walyus, Keith D.; Reis, James; Bradley, Arthur J.

2002-12-01

393

Satellite voice broadcast system study, volume 2  

NASA Technical Reports Server (NTRS)

This study investigates the feasibility of providing Voice of America (VOA) broadcasts by satellite relay, rather than via terrestrial relay stations. Satellite voice broadcast systems are described for three different frequency bands: HF (26 MHz), VHF (68 MHz), and L-band (1.5 GHz). The geographical areas of interest at HF and L-band include all major land masses worldwide with the exception of the U.S., Canada, and Australia. Geostationary satellite configurations are considered for both frequency bands. In addition, a system of subsynchronous, circular satellites with an orbit period of 8 hours is developed for the HF band. VHF broadcasts, which are confined to the Soviet Union, are provied by a system of Molniya satellites. Satellites intended for HF or VHF broadcastinbg are extremely large and heavy. Satellite designs presented here are limited in size and weight to the capability of the STS/Centaur launch vehicle combination. Even so, at HF it would take 47 geostationary satellites or 20 satellites in 8-hour orbits to fully satisfy the voice-channel requirements of the broadcast schedule provided by VOA. On the other hand, three Molniya satellites suffice for the geographically restricted schedule at VHF. At L-band, only four geostationary satellites are needed to meet the requirements of the complete broadcast schedule. Moreover, these satellites are comparable in size and weight to current satellites designed for direct broadcast of video program material.

Horstein, M.

1985-01-01

394

Interannual variation in biomass burning and fire seasonality derived from geostationary satellite data across the contiguous United States from 1995 to 2011  

NASA Astrophysics Data System (ADS)

Wildfires exhibit a strong seasonality that is driven by climatic factors and human activities. Although the fire seasonality is commonly determined using burned area and fire frequency, it could also be quantified using biomass consumption estimates that directly represent biomass loss (a combination of the area burned and the fuel loading). Therefore, in this study a data set of long-term biomass consumed was derived from geostationary satellite data to explore the interannual variation in the fire seasonality and the possible impacts of climate change and land management practices across the Contiguous United States (CONUS). Specifically, daily biomass consumed data were derived using the fire radiative power retrieved from Geostationary Operational Environmental Satellites series with a pixel size of 4-10 km from 1995 to 2011. Annual fire seasonality metrics including the fire season duration, the timing of the start, peak, and end of the fire season, and interannual variation and trends were derived from the 17 year biomass consumed record. These metrics were associated with climatic factors to examine drivers and mediators of fire seasonality. The results indicate that biomass consumed significantly increased at a rate of 2.87 Tg/yr; however, the derived fire season duration exhibited a shortening trend in various states over the western CONUS and no significant trend in most other regions. This suggests that the frequency of extreme fire events has increased, which is perhaps associated with an observed increase of extreme weather conditions. Further, both the start and the end of the fire season exhibited an early shift (1.5-5 d/yr) in various eastern states although a late shift occurred in Arizona and Oregon. The interannual variation and trend in the fire seasonality was more strongly related to temperature in the western CONUS and to precipitation in the southeast. The Palmer Drought Severity Index was found to effectively reflect interannual variations in total biomass consumed although it was poorly correlated to the fire seasonality metrics. The results indicate that across the CONUS, the spatial patterns of the start, peak, and end of the fire season shift regularly in various regions in response to latitudinal gradients of temperature variation.

Zhang, Xiaoyang; Kondragunta, Shobha; Roy, David P.

2014-06-01

395

Placing a telecommunications satellite in orbit. I - Telecom 1  

NASA Astrophysics Data System (ADS)

An in-depth description is presented of the placement of a telecommunications satellite on GEO. Highlights of the launch of the Telecom 1A from Kourou on an Ariane vehicle in August 1984 are used to illustrate the process. After initial boost to space on the way to GEO, the spacecraft was first placed in a transfer orbit with a perigee of 200 km and an apogee of 36,000 km, then spun up to 7 rpm. The orbit was then circularized by firing the Mage 2 solid propellant apogee kick booster. Hydrazine thrusters then increased the spin speed from 7 to 9 rpm, from 9 to 55 rpm, and finally from 55 to 60 rpm. The final boosts placed Telecom 1 into a drift orbit to achieve a small plane change into a purely equatorial orbit. The final burns were controlled from the ground using distance, Doppler shift, and angular measurements of the spacecraft position as input to orbital and propulsive burn calculations.

Husson, J.-C.

396

A mission to preserve the Geostationary Region (ROGER)  

NASA Astrophysics Data System (ADS)

The high strategic and commercial value of the geostationary region is unquestioned. It is known that many satellites are not re-orbited at the end of their mission for a number of reasons. Previous studies have investigated the possibility of rendezvous and docking with an uncontrolled target and concluded a basic technical plausibility. Thus the possibility exists that spent satellites could be removed from the operational region by one or more shuttle vehicles. This is the basis for the European Space Agency (ESA/ESTEC) study entitled Robotic Geostationary Orbit Restorer (ROGER). In full, the ROGER study will address the collision risk in GEO, identify workable economic and technical mission scenarios and propose a solution. To enable an accurate quantification of the risk in the operational GEO region a detailed assessment of the current and future status has been performed. This paper will present the results of this analysis, which includes a breakdown of the current utilisation of the GEO ring and an assessment of the satellite failures that have afflicted GEO satellites. Also considered are the general trends in the GEO market and the tendencies of satellite operators to remove their assets from the operational GEO region at the end of their useful life. All of these analyses are brought together in a GEO Simulator, which is designed to determine the collision risk in GEO and the effect that satellite failures, future launch traffic and re-orbiting trends have on this risk. Drawing on this assessment of current and future GEO utilisation, a list of potential ROGER mission scenarios has been generated. For each case the major technical issues are assessed with respect to the available technology, and cost and schedule implications are compared with economic issues such as sources of funding. In this way, cases for government and commercial funding of a ROGER mission are examined. This paper will present examples of such analyses and discuss the rationale behind a possible solution.

Smith, D.; Martin, K. C.; Petersen, H.; Shaw, A.; Skidmore, B.; Smith, D.; Stokes, H.; Willig, A.

397

The Principle of Navigation Constellation Composed of SIGSO Communication Satellites  

E-print Network

The Chinese Area Positioning System (CAPS), a navigation system based on GEO communication satellites, was developed in 2002 by astronomers at Chinese Academy of Sciences. Extensive positioning experiments of CAPS have been performed since 2005. On the basis of CAPS, this paper studies the principle of navigation constellation composed of Slightly Inclined Geostationary Orbit (SIGSO) communication satellites. SIGSO satellites are derived from end-of-life Geostationary Orbit (GEO) satellites under inclined orbit operation. Considering the abundant frequency resources of SIGSO satellites, multi-frequency observations could be conducted to enhance the precision of pseudorange measurements and ameliorate the positioning performence. The constellation composed of two GEO satellites and four SIGSO satellites with inclination of 5 degrees can provide the most territory of China with 24-hour maximum PDOP less than 42. With synthetic utilization of the truncated precise (TP) code and physical augmentation factor in fo...

Ji, Hai-Fu; Ai, Guo-Xiang; Shi, Hu-Li

2012-01-01

398

A Low Earth Orbit satellite marine communication system demonstration  

NASA Technical Reports Server (NTRS)

An application of Low Earth Orbit (LEO) satellite communications technology was investigated during a joint Canadian/American scientific expedition to the north pole in the summer of 1994. The Canadian ice breaker involved, was equipped with a store-and-forward LEO satellite terminal which was linked to a ground station in St. John's, Newfoundland, via the near-polar-orbiting satellite, HealthSat-l. The objective was to evaluate the performance of such a system while providing an alternate means of communications in the far north. The system performed well, given its inherent limitations. All 151 attempts to send data files to the ship were successful. Only two (2) of the 35 attempts to send files from the ship were unsuccessful. The files ranged in size from 0.1 to 60 Kbytes. In the high arctic, above 80 deg north, this system often provided the only practical means of data communications. This experiment demonstrated the potential of such a system for not-real-time communications with remote and/or mobile stations, and highlighted the many issues involved. This paper describes the project objectives, system configuration and experimental procedure used, related technical issues, trial results, future work, and conclusions.

Elms, T. Keith; Butt, Kenneth A.; Asmus, Ken W.

1995-01-01

399

Communications satellite systems capacity analysis  

NASA Technical Reports Server (NTRS)

Analog and digital modulation techniques are compared with regard to efficient use of the geostationary orbit by communications satellites. Included is the definition of the baseline systems (both space and ground segments), determination of interference susceptibility, calculation of orbit spacing, and evaluation of relative costs. It is assumed that voice or TV is communicated at 14/11 GHz using either FM or QPSK modulation. Both the Fixed-Satellite Service and the Broadcasting-Satellite Service are considered. For most of the cases examined the digital approach requires a satellite spacing less than or equal to that required by the analog approach.

Browne, L.; Hines, T.; Tunstall, B.

1982-01-01

400

47 CFR 25.140 - Further requirements for license applications for geostationary space stations in the Fixed...  

Code of Federal Regulations, 2014 CFR

...for license applications for geostationary space stations in the Fixed-Satellite Service...COMMUNICATIONS Applications and Licenses Space Stations § 25.140 Further requirements...for license applications for geostationary space stations in the Fixed-Satellite...

2014-10-01

401

An investigation of selected on-orbit satellite servicing issues  

NASA Technical Reports Server (NTRS)

The results of three separate investigations performed by Science Applications International Corporation (SAIC) between August 1985 and October 1986 as the second phase of the two-phase Satellite Services System Program Plan contract for the Engineering Directorate of the Lyndon B. Johnson Space Center are discussed. The objectives of the first phase of this contract (reported in SAIC-85/1762) were to determine the potential for servicing a diverse range of spacecraft from the Space Shuttle Orbiter and to assess NASA's role as the catalyst in enabling routine on-orbit servicing. The second area of investigation was prompted by the need to understand satellite servicing requirements in the far term (1995 to 2010) and how results from the first phase of this contract could support these requirements. The mission model developed during the first phase was extended using new data and information from studies which address the later time period. The third area of investigation looked at a new servicing mode which had not been studied previously. This mode involves the on-orbit exchange of very large modules with masses greater than approximately 9,000 kilograms and/or lengths greater than approximately nine meters. The viewgraphs used for the final briefing for each of the three investigations, as presented to NASA are given.

Hoffman, Stephen J.

1986-01-01

402

GOES-R satellite solar panels ready for space  

NASA Astrophysics Data System (ADS)

An array of five photovoltaic panels has been approved and is ready to be incorporated into the National Oceanic and Atmospheric Administration's (NOAA) new Geostationary Operational Environmental Satellites-R (GOES-R). GOES-R, a collaborative effort between NOAA and NASA, aims to provide more timely and accurate weather forecasts once in orbit. The satellite is scheduled to launch in early 2016.

Wendel, JoAnna

2014-07-01

403

Astrometric observations of natural satellites and orbit update , Cheng X.1,2  

E-print Network

181 Astrometric observations of natural satellites and orbit update Xi X.J.1,2 , Cheng X.1 100039, China Abstract: This paper reports on our observing campaign of nature satellites and orbit research of photo plates. 1 Research History In 1985, we start our research on natural satellites

Paris-Sud XI, Université de

404

STATIONARY CONFIGURATIONS FOR CO-ORBITAL SATELLITES WITH SMALL ARBITRARY MASSES  

E-print Network

STATIONARY CONFIGURATIONS FOR CO-ORBITAL SATELLITES WITH SMALL ARBITRARY MASSES STÉFAN RENNER results on the existence of stationary configurations for N co-orbital satellites with small but otherwise between the satellites, there always exists a set of masses (positive or negative) which achieves

Demoulin, Pascal

405

Revisiting elliptical satellite orbits to enhance the O3b constellation  

E-print Network

leaves apogee, another satellite entering apogee takes its place, with handover of communication, from1 Revisiting elliptical satellite orbits to enhance the O3b constellation Lloyd Wood University satellite coverage of locations at high latitudes. We review the history of use of these orbits

Wood, Lloyd

406

Assimilation of next generation geostationary aerosol optical depth retrievals to improve air quality simulations  

NASA Astrophysics Data System (ADS)

Planned geostationary satellites will provide aerosol optical depth (AOD) retrievals at high temporal and spatial resolution which will be incorporated into current assimilation systems that use low-Earth orbiting (e.g., Moderate Resolution Imaging Spectroradiometer (MODIS)) AOD. The impacts of such additions are explored in a real case scenario using AOD from the Geostationary Ocean Color Imager (GOCI) on board of the Communication, Ocean, and Meteorology Satellite, a geostationary satellite observing northeast Asia. The addition of GOCI AOD into the assimilation system generated positive impacts, which were found to be substantial in comparison to only assimilating MODIS AOD. We found that GOCI AOD can help significantly to improve surface air quality simulations in Korea for dust, biomass burning smoke, and anthropogenic pollution episodes when the model represents the extent of the pollution episodes and retrievals are not contaminated by clouds. We anticipate future geostationary missions to considerably contribute to air quality forecasting and provide better reanalyses for health assessments and climate studies.

Saide, Pablo E.; Kim, Jhoon; Song, Chul H.; Choi, Myungje; Cheng, Yafang; Carmichael, Gregory R.

2014-12-01

407

Artificial Crater Formation on Satellite Surfaces Using an Orbiting Railgun  

NASA Technical Reports Server (NTRS)

The specification of greater than 45kW of disposable power available on the JIMO spacecraft raises the possibility of a new class of instrumentation that has utility at such power levels. In this presentation we discuss the concept of an electromagnetic mass driver that can launch projectiles from orbit around one of the Galilean satellites directed on a trajectory that will impact the satellite surface. The resulting impact will create a crater that will provide information on the mechanical properties of surface and near-surface materials, expose subsurface materials for remote spectral identification, and form a vapor cloud that can be sensed for composition either remotely or in-situ. An analog for such a controlled cratering experiment is Deep Impact, a mission to observe the crater and ensuing ejecta cloud formed by a ballistic projectile into a comet surface in July, 2005.

Dissly, R. W.; Miller, K. L.; Carlson, R. J.

2003-01-01

408

Orbits of the Martian satellites from ESAPHO and ESADE theories  

NASA Astrophysics Data System (ADS)

The semi-analytical theories ESAPHO and ESADE for the orbital motions of the Martian satellites have been fitted to a large collection of observations including earth-based observations and spacecraft observations from Mariner 9, Viking 1 and 2 and Phobos 2. The influences of various subsets of observations and of the weights assigned to them have been analyzed. The contribution of the perturbations by Phobos' figure has been studied. An interesting agreement of the perturbations computed from Borderies and Yoder's values of inertial parameters with the observations has been obtained.

Chapront-Touze, M.

1990-12-01

409

Analysis of Errors in a Special Perturbations Satellite Orbit Propagator  

SciTech Connect

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

Beckerman, M.; Jones, J.P.

1999-02-01

410

Meteorological satellites  

NASA Technical Reports Server (NTRS)

An overview is presented of the meteorological satellite programs that have been evolving from 1958 to the present, and plans for the future meteorological and environmental satellite systems that are scheduled to be placed into service in the early 1980's are reviewed. The development of the TIROS family of weather satellites, including TIROS, ESSA, ITOS/NOAA, and the present TIROS-N (the third generation operational system) is summarized. The contribution of the Nimbus and ATS technology satellites to the development of the operational-orbiting and geostationary satellites is discussed. Included are descriptions of both the TIROS-N and the DMSP payloads currently under development to assure a continued and orderly growth of these systems into the 1980's.

Allison, L. J. (editor); Schnapf, A.; Diesen, B. C., III; Martin, P. S.; Schwalb, A.; Bandeen, W. R.

1980-01-01

411

Evapotranspiration estimated by using datasets from the Chinese FengYun-2D geostationary meteorological satellite over the Yellow River source area  

NASA Astrophysics Data System (ADS)

In this paper, we developed algorithms to estimate hourly evapotranspiration (ET) during a day under clear and cloud cover conditions using data from the Chinese FengYun-2D (FY-2D) geostationary meteorological satellite over the Yellow River source area. For cloud-free conditions, the Surface Energy Balance System (SEBS) methodology and FY-2D data were used to derive the hourly ET. For cloudy cover conditions, the transmission coefficient was calculated using top of atmosphere (TOA) reflectance and the attenuation of solar radiation in the atmosphere. Heat fluxes and ET under different atmospheric and cloud cover conditions were then calculated. Compared with ground-based measurements from eddy covariance systems deployed in the Maqu Climate and Environment Comprehensive Observation Station, the average relative error was 15.20% during the experimental period. The proposed methodology can rely exclusively on remote sensing data in the absence of ancillary ground observations. Thus, the proposed method can potentially estimate the regional surface energy budget.

Liu, Rong; Wen, Jun; Wang, Xin; Zhang, Yu

2015-01-01

412

Alternative packet switch architectures for a 30/20 GHz FDMA/TDMA geostationary communication satellite network  

NASA Technical Reports Server (NTRS)

This study has investigated alternatives for realizing a packet-based network switch for deployment on a communication satellite. The emphasis was on the avoidance of contention problems that can occur due to the simultaneous arrival of an excessive number of packets destined for the same downlink dwell. The study was to look ahead, beyond the current Advanced Communications Technology Satellite (ACTS) capability, to the next generation of satellites. The study has not been limited by currently available technology, but has used university and commercial research efforts as a basis for designs that can be readily constructed and launched within the next five years. Tradeoffs in memory requirement, power requirement, and architecture have been considered as a part of our study.

Stehle, Roy; Ogier, Richard G.