A discussion of the use of spherical approximation or no approximation in gravity field modeling with emphasis on unsolved problems in Least-Squares Collocation

  • C. C. Tscherning
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 127)


Spherical approximation is widely used in gravity field modeling, but it causes errors of the order of the flattening. Different methods for avoiding using this approximation when linearizing observation functionals are possible due to our improved knowledge of the gravity field and of the surface of the Earth. However a number of problems are not solved today, such as those related to the use of a Bjerhammar sphere in Least-Squares Collocation (LSC). If this concept is used, the associated homogeneous /isotropic kernels in genera] use will be strongly non-homogeneous on the ellipsoid. A possible solution is to use a “Bjerhammar” ellipsoid inside the Earth.


Gravity Anomaly Gravity Vector Spherical Approximation Gravity Field Modeling Geoid Undulation 
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© Springer-Verlag Berlin Heidelberg 2004

Authors and Affiliations

  • C. C. Tscherning
    • 1
  1. 1.Department of GeophysicsUniversity of CopenhagenCopenhagen ØDenmark

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