Advertisement

Quality Improvement of Global Gravity Field Models by Combining Satellite Gradiometry and Airborne Gravimetry

  • Johannes Bouman
  • Radboud Koop
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 122)

Abstract

The expected high resolution and precision of a global gravity field model derived from satellite gradiometric observations is unprecedented compared to nowadays satellite-only models. However, a dedicated gravity field mission will most certainly fly in a non-polar (sun-synchronous) orbit, such that small polar regions will not be covered with observations. The resulting inhomogeneous global data coverage, together with the downward continuation problem, leads to unstable global solutions and regularization is necessary. Regularization gives rise to a bias in the solution, mainly in the polar areas although in other regions as well.

Undoubtedly, the combination with gravity related measurements in the polar areas, like airborne gravimetry, will improve the stability of the solution. Consequently, the bias is reduced and the quality is likely to be better. Open questions are, for example, how accurate gravity anomalies must be, what spatial sampling is required, and how large the area with observations should be. Moreover, it is unknown whether measurements in one polar area only (e.g. North Pole) is sufficient.

In order to answer these questions, a gravity field solution from gradiometry-only will be compared with a solution from gradiometry combined with several airborne gravimetric scenarios. Special attention is given to the quality improvement and bias reduction relative to the gradiometry-only solution. The coefficients of a spherical harmonic series are the unknowns and their errors are propagated to, for example, geoid heights.

Keywords

Gravity Field Gravity Anomaly Gravity Data Geoid Height Airborne Gravimetry 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. ESA (1996). Gravity Field and Steady-State Ocean Circulation Mission. Reports for assessment. ESA SP-1196(1).Google Scholar
  2. Haagmans, R. and van Gelderem, M. (1991). Error variances-covariances of GEM-T1: their characteristic and implications in geoid computation. Journal of Geophysic Research, 96(B12):20011–20022.CrossRefGoogle Scholar
  3. Hoerl, A. and Kennard, R. (1970). Ridge regression: biased estimation for nonorthogonal problems. Technometrics, 12(1):55–67.CrossRefGoogle Scholar
  4. Koop, R. (1993). Global gravity field modelling using satellite gravity gradiometry. Publications on geodesy. New series no. 38.Google Scholar
  5. Louis, A. (1989). Inverse und schlecht gestellte Probleme. Teubner.Google Scholar
  6. Marsh, J., Lerch, F., Putney, B., Christodoulidis, D., Smith, D., Felsentreger, T., Sanchez, B., Klosko, S., Pavlis, E., Martin, T., Williamson, J.R. R., Colombo, O., Rowlands, D., Eddy, W., Chandler, N., Rachlin, K., Patel, G., Bhati, S., and Chinn, D. (1988). A new gravitational model for the earth from satellite tracking data: GEM-T1. Journal of Geophysical Research, 93(B6):6169–6215.CrossRefGoogle Scholar
  7. Rummel, R., van Gelderen, M., Koop, R., Schrama, E., Sansò, F., Brovelli, M., Migliaccio, F., and Sacerdote, F. (1993). Spherical harmonic analysis of satellite gradiometry. Publcations on geodesy. New sereies no. 39.Google Scholar
  8. Schrama, E. (1990). Gravity field error analysis: application of GPS recievers and gradiometers on low orbiting platforms. TM 100769, NASA.Google Scholar
  9. Schwarz, K. and Li, Z. (1997). An introduction to airborne gravimetry and its boundary value problems. In Sansò, F. and Rummel, R., editors, Geodetic Boundary Value Problems in View of the One Centimeter Geoid, volume 65 of Lecture Notes in earth science, pages 312–328. Springier-Verlag.Google Scholar
  10. Tikhonov, A. and Arsenin, V. (1977). Solution of ill-posed problems. Winston and Sons.Google Scholar
  11. Xu, P. (1992). The value of minimum norm estimation of geopotential fields. Geophysical Journal International, 111:170–178.CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Johannes Bouman
    • 1
  • Radboud Koop
    • 1
  1. 1.Faculty of Geodetic EngineeringDelft University of TechnologyDelftNetherlands

Personalised recommendations