Sökning: "Geoid"

Visar resultat 1 - 5 av 16 avhandlingar innehållade ordet Geoid.

  1. 1. Geoid Model of Tanzania from Sparse and Varying Gravity Data Density by the KTH method

    Författare :Prosper Ulotu; Lars Sjöberg; Hossein Nahavandchi; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geoid; sparse gravity data; gravity database; GGM validation by gravity; corrector surface; hybrid geoid; KTH-LSMS with AC; Mt. Kilimanjaro; Tanzania.; Earth sciences; Geovetenskap;

    Sammanfattning : Developed countries are striving to achieve a cm geoid model. Most developing countries/regions think that the situation in their areas does not allow even a few decimetre geoid model. GNSS, which provides us with position, is one of the greatest achievements of the present time. LÄS MER

  2. 2. Least squares modification of Stokes formula with application to the Estonian geoid

    Författare :Artu Ellmann; KTH; []
    Nyckelord :geoid; stokes formula; least sequares modification; total topographic correction; total atmospheric correction; gps levelling;

    Sammanfattning : Many applications in geodesy,geophysics and engineering require physically defined heightsrelated to an equipotential surface of the Earth, thegeoid.During the last two decades theincreased need for refined geoid models has been driven by thedemands of users of GPS, who nowadays must transformGPS-derived geodetic heights into orthometric heights, makingthem compatible with the local vertical datum. LÄS MER

  3. 3. The geoid for the Baltic countries determined by the least squares modification of Stokes´formula

    Författare :Artu Ellmann; KTH; []
    Nyckelord :geoid; Stokes;

    Sammanfattning : Precise knowledge of the geoid contributes to the studies ofthe Earth’s interior, the long-term geophysical processesand to oceanography. An accurate regional geoid model, inparticular, enables the user in many cases to replace thetraditional height determination techniques by faster and morecost-effective GPS-levelling. LÄS MER

  4. 4. Regional Geoid Determination Methods for the Era of Satellite Gravimetry : Numerical Investigations Using Synthetic Earth Gravity Models

    Författare :Jonas Ågren; Lars E. Sjöberg; Zdenek Martince; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; geoid determination; GOCE; synthetic earth gravity models; kernel modification; downward continuation; Geovetenskap; Earth sciences; Geovetenskap;

    Sammanfattning : It is the purpose of this thesis to investigate different regional geoid determination methods with respect to their feasibility for use with a future GOCE satellite-only Earth Gravity Model (EGM). This includes investigations of various techniques, which involve different approximations, as well as the expected accuracy. LÄS MER

  5. 5. Mold2012 : a new gravimetric quasigeoid model over Moldova

    Författare :Uliana Danila; Lars E. Sjöberg; Stig-Göran Mårtensson; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; geoid; quasigeoid; KTH method; corrective surface;

    Sammanfattning : In order to be able to use the operational Moldavian GNSS Positioning System MOLDPOS efficiently for the determination of normal heights in surveying engineering, e.g. during the construction of a road, an accurate quasigeoid model is needed. LÄS MER