Search for dissertations about: "global positioning system"

Showing result 21 - 25 of 73 swedish dissertations containing the words global positioning system.

  2. 21. Space Geodesy Techniques: An Experimental and Theoretical Study of Antenna Related Error Sources

    Author : R. T. Kenneth Jaldehag; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reflector antennas; signal scattering; very long baseline interferometry VLBI ; signal multipath; space geodesy; GPS error sources; geodetic networks; Global Positioning System GPS ; postglacial rebound; choke-ring antennas;

    Abstract : This thesis presents work associated with antenna related error sources, as well as antenna design, in space geodesy utilizing the techniques of Very-Long-Baseline Interferometry (VLBI) and the Global Positioning System (GPS). Geodetic VLBI uses large radio telescopes, often in global networks observing at least a few times per year. READ MORE

  4. 22. Frequency Transfer Techniques and Applications in Fiber Optic Communication Systems

    Author : Sven-Christian Ebenhag; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; synchronous digital hierarchy SDH ; UTC; synchronization; Time transfer; optical fiber; optical fiber network; GPS carrier phase; global positioning system GPS ; synchronous optical networking SONET ;

    Abstract : Modern society is dependent on communications and the developments of these increases constantly through a seemingly endless demand for communication services and thereby synchronization and time. This is confirmed by a vast range of research on communications, irrespective of technology and protocol. READ MORE

  5. 23. Measuring and modelling variations in the distribution of atmospheric water vapour using GPS

    Author : Tobias Nilsson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Global Positioning System GPS ; Microwave Radiometry; Water Vapour; Climate; Atmospheric Turbulence;

    Abstract : Turbulence introduce variations in the refractive index of air, which in turn result in fluctuations in the phase and amplitude of radio signals propagating through the atmosphere. Most important are the variations due to fluctuations in the water vapour field. READ MORE

  6. 24. Site dependent error sources in geodetic Very-Long-Baseline Interferometry

    Author : T. Ragne Carlsson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; space geodecy; Water Vapor Radiometer WVR ; very-long-baseling interferometry VLBI ; Global Positioning System GPS ; Kalman filtering;

    Abstract : .... READ MORE

  7. 25. Food for Naught : The politics of food in agricultural modernization for African smallholder food security

    Author : Cheryl Sjöström; LUCSUS; []
    Keywords : SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; global food system; smallholder food security; sub-Saharan Africa; agricultural modernization; critical discourse analysis; power; politics of food; Millennium Villages Project; Malawi;

    Abstract : Why is there hunger in sub-Saharan Africa? What forces drive the global food system? What is the global food system? To approach these questions, this study investigates power and politics in food, in its production and in its organization. Proceeding from a critical realist approach, focus of this study is on the challenge of African smallholder food insecurity and how it is presented as part of a dominant discourse of agricultural modernization. READ MORE