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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Possibilities for limb sounding the earth's atmosphere from a geostationary satellite

Mlynczak, Martin Gerard. January 1984 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 59-60).
2

Implementation of digital modulation techniques using direct digital synthesis /

Shankar, Udaya. January 1993 (has links)
Report (M.S.)--Virginia Polytechnic Institute and State University. M.S. 1993. / Vita. Abstract. Includes bibliographical references (leaves 31-32). Also available via the Internet.
3

Impact of ion propulsion on performance, design, testing and operation of a geosynchronous spacecraft

Lugtu, Spotrizano Descanzo. January 1990 (has links)
Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, June 1990. / Thesis Advisor(s): Agrawal, Brij N. Second Reader: Biblarz, Oscar. "June 2009." Description based on title screen as viewed on 19 October 2009. DTIC Identifier(s): Ion propulsion, synchronous satellites, NSSK (North South Station Keeping). Author(s) subject terms: Ion propulsion, geosynchronous satellite, North-South Station Keeping. Includes bibliographical references (p. 153-156). Also available in print.
4

System engineering of a crosslink for geostationary communications satellites /

Knupp, Greg L. January 1993 (has links)
Report (M.S.)--Virginia Polytechnic Institute and State University. M.S. 1993. / Abstract. Includes bibliographical references (leaves 80-81). Also available via the Internet.
5

Transport, network, and data link layer protocol designs to improve geo-stationary Earth orbit satellite data set transmission performance

Wiedemeier, Paul Douglas, January 2005 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2005. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (May 25, 2006) Vita. Includes bibliographical references.
6

Assessment of synchronization in the SDH satellite sector

Van Wyk, Carel Johannes 17 August 2012 (has links)
M.Ing. / The increase of multimedia and broadband communications in recent years has brought about the creation and implementation of synchronousdigital hierarchy (SDH) in the terrestrial network. The implementation of SDH in the satellite sector is a natural extension to improve the current available networks. It will drastically increase the flexibility and usability of the current under-utilized satellite sector. Unfortunately, SDH has still not been implemented in the satellite sector due to certain inherent synchronization problems of SDH and satellites. This thesis investigates some of these synchronization problems. A simulation tool was created that makes an accurate assessment of SDH synchronization in the satellite sector. The tool was used to study SDH links over goestationary (GEO), medium earth orbiting (MEO) and low earth orbiting (LEO) satellites. Various changeable SDH parameters were investigated to determine their influences. Parameters like the bit rate and elastic store length or hysteresis lengths were considered.
7

Cold-deciduous broadleaf phenology: monitoring using a geostationary satellite and predicting using trigger-less dynamic models

Wheeler, Kathryn I. 07 February 2024 (has links)
Vegetation phenology serves as a primary ecological indicator of climate change and has numerous ecosystem and climate impacts including nutrient cycling, energy budgets, and annual primary productivity. Phenology models, especially ones of autumnal processes like senescence, are typically based on correlations between environmental threshold triggers and transition dates and less is known about the specific mechanisms behind phenological events. Higher temporal resolution satellite data is needed to continue to identify the mechanisms at larger scales. It is unclear if a start of senescence (SOS) trigger is needed in mechanistic models and if decreased photosynthesis drives senescence. In this dissertation, I have two main themes: the first (Chapters 2 and 3) is to investigate the potential of the Geostationary Operational Environmental Satellite (GOES) to track changes to the phenology-sensitive Normalized Difference Vegetation Index (NDVI) and the second (Chapters 4 and 5) is to develop dynamic mechanistic models to predict senescence in cold-deciduous broadleaf forests. In Chapter 2, I created a novel statistical model to estimate daily NDVI with uncertainty from high temporal resolution (five - ten minutes) GOES-16 and -17 data. In Chapter 3, I used this data to track forest phenology by fitting double-logistic Bayesian models and comparing transition dates to those obtained from PhenoCams (digital cameras) and the Moderate Resolution Imaging Spectroradiometer (MODIS). Compared to MODIS, GOES was more correlated with PhenoCam at the start and middle of spring. In Chapter 4, I developed a dynamic Bayesian model based on the physiological process of chlorophyll cycling that assumes a constant chlorophyll breakdown rate and synthesis dependent on temperature and photoperiod to predict senescence without including a SOS trigger or degree-day memory. I fit the model to greenness time series from 24 PhenoCam sites and found that for 49% of the site-years the model could predict SOS using only pre-SOS data. Furthermore, the model could regularly predict greenness at other sites better than their climatologies. In Chapter 5, I investigated if including photosynthetic feedbacks could improve the chlorophyll synthesis model at the canopy and leaf-levels. Testing this against leaf-level measurements of photosynthetic capacity and changes in chlorophyll concentrations of Fagus grandifolia and Quercus rubra demonstrated that the model fit improved at the canopy level, but not at the leaf-level. This dissertation illustrates that GOES can track phenology and that senescence in cold-deciduous broadleaf forests might not be initiated with a threshold-based trigger.
8

An attitude and orbit determination and control system for a small geostationary satellite /

Thopil, G. A. January 2006 (has links)
Thesis (MScIng)--University of Stellenbosch, 2006. / Bibliography. Also available via the Internet.
9

Satellite orbit determination using GPS carrier phase in pure kinematic mode /

Byun, Sung Hun, January 1998 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 226-231). Available also in a digital version from Dissertation Abstracts.
10

A high gain tri-reflector antenna configuration for beam scanning /

Werntz, Paul C., January 1993 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.

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