Evaluation of the EGM2008 and GOCE global geoid models versus the Laplace points in Iran

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Abstract

The deflection of vertical components, are the second order spatial derivatives of the gravity potential, efficiently counteract signal attenuation at the low and medium frequencies. Regional gravimetric geoid and quasi-geoid models are now commonly fitted to GPS-leveling data, which simultaneously absorb GPS/leveling and quasi/geoid errors due to their inseparability. We propose that independent vertical deflections are used instead as they are not affected by this inseparability problem. The formulation is set out for geoid slopes and changes in slopes. In this research, 10 Laplace points form the Iranian astro-geodetic networks were utilized for calibration and combination of the EGM2008 and GOCE global geoid models. Several two-, three- and four-parameter- models were used as a correction surface for the combination and evaluation of the geoid models. The standard deviation of the deflection of vertical components before and after fitting in geoid models evaluated with independent data. The results showed a significant improvement in the N-S direction of the GOCE model from 0.095 to 0.003 and in the E-W direction of the EGM2008 model from 0.246 to 0.008. To sum up, the two-parameter models worked best among the other corrective surface models. Also, the EGM2008 model gave slightly better results versus the GOCE model. For any future researches, use of homogenous and high quality zenith-nadir digital camera data is strongly recommended.

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References

Bomford, G. 1980, Geodesy: 4th edn. OxfordUniversity Press, Oxford.
Farin,G.E., 2001, Curves and Surfaces for CAGD: A Practical Guide: 5th edn. Morgan Kaufmann,San Francisco.
 Featherstone, W. E., 1999, The use and abuse of vertical deflections: The Australian Surveyor, 86-96.
Featherstone, W. E., 2001, Absolute and relative testing of gravimetric geoid models using global positioning system and orthometric height data: Comput. Geosci. 27(7), 807-814. doi:10.1016/S0098-3004(00)00169-2
Featherstone, W. E., 2004, Evidence of a north-south trend between AUSGeoid and AHD in southwest Australia: Surv. Rev., 37(291), 334-343.
Featherston, W. E., 2006, Yet more evidence for a north-south slope in the AHD: J. Spat. Sci., 51(2), 1-6; corrigendum in 52(1), 65-68.
Featherston, W.E, Rüeger, J.M., 2000, The importance of using deviations of the vertical in the reduction of terrestrial survey data to a geocentric datum: Trans. Tasman Surv., 1(3), 46-61(erratum in Aust. Surv. 47(1), 7).
Featherston, W.E, Sproule, D.M., 2006, Fitting AUSGeoid98 to the Australian height datum using GPS data and least squares collocation: application of a cross validation technique: Surv. Rev., 38(301): 573-582.
Featherston, W. E., Morgan, L., 2007, Validation of the AUSGeoid98 model in Western Australia using historic astrogeodetically observed deviations of the vertical: J. R. Soc. West. Aust., 90(3), 143-149.
Featherston, W. E., and Lichti, D.D., 2009, Fitting gravimetric geoid models to vertical deflections: J. Geod., 83, 583-589. doi: 10.1007/s00190-008-0263-4
Forsberg, R., 1998, Geoid tailoring to GPS with example of a 1-cm geoid of Denmark: Finnish Geodetic Institute Report 98(4): 191- 198
Fotopoulos, G., 2005, Calibration of geoid error models via a combined adjustment of ellipsoidal, orthometric and gravimetric geoid height data: J. Geod. 79(1-3), 111-123. doi:10.1007/s00190-005-0449-y
Grafarend, E. W., 1997, Field lines of gravity, their curvature and torsion, the Lagrange and the Hamilton equations of the plumbline: Ann. Geophys., 40(5), 1233-1247.
Heiskanen, W. A., and Moritz, H., 1967, Physical Geodesy: Freeman, San Francisco.
Hirt, C., Seeber, G., 2007, High – resolution local gravity field determination at the sub- millimeter level using a digital zenith camera system: in Tregoning P, Rizos C(eds) Dynamic Planet, Springer, Berlin, pp 316-321.
Jekeli, C., 1999, An analysis of vertical deflections derived from high-degree spherical harmonic models: J. Geod., 73(1), 10-22. doi:10.1007/s001900050213
Jiang Z, Duquenne, H., 1996, On the combined adjustment of a gravimetrically determined geoid and GPS leveling stations: J. Geod. 70(8), 505-514. doi:10.1007/s001900050039
Kotsakis, C., Sideris, M. G., 1999, On the adjustment of combined GPS/leveling/geoid networks: J. Geod., 73(8), 412-421. doi:10.1007/s001900050261
Mather, R. S., 1970, The geodetic orientation vector for the Australian geodetic datum: Geophys. J. R. Astron. Soc., 22(1), 55-81. doi:10.1111/j.1365-246X.1971. tb03583.x
Milbert , D.G., 1995, Improvement of a high resolution geoid model in the United States by GPS height on NAVD88 benchmarks: Int. Geoid. Serv. Bull., 4, 13-36.
Müller A, Bürki B, Limpach P, Kahle HG, Grigoriadis VN, Vergos GS, Tziavos IN (2007)
Validation of marine geoid models in the North Aegean Sea using satellite altimetry, marine
GPS data and astrogeodetic measurements, in: Kiliçoğlu A, Forsberg R (eds) Gravity Field of the Earth, General Command of Mapping, AnkaraPail R., Bruinsma S., Migliaccio F., Förste C., Goiginger H., Schuh W.-D., Höck E., Reguzzoni M., Brockmann J. M., Abrikosov O., Veicherts M., Fecher T., Mayrhofer R., Krasbutter I., Sansò F., and Tscherning C. C. 2011, First GOCE gravity field models derived by three different approaches: Journal of Geodesy, 85(11), 819-843. doi: 10.1007/s00190-011-0467-x
Pavlis, N. K., Holmes, S. A., Kenyon, S. C., and Factor, J. K., 2008, An earth gravitational model to degree 2160: EGM2008. EGU General Assembly,Vienna
Soltanpour, A., Nahavandchi, H., and Featherstone, W. E., 2006, The use of second-generation wavelets to combine a gravimetric geoid model with GPS-levelling data: J. Geod., 802, 82-93. doi:10.1007/s00190-006-0033-0
Tenzer, R.,Vaníček, P., and Santos, M., Featherstone, W.E.,Kuhn, M., 2005, The rigorous determination of orthometric heights: J. Geod., 79(1-3), 82-92. doi:10.1007/s00190-005-0445-2
Torge, W., 2001, Geodesy: 3rd Edn. de Gruyter, Berlin.
Iranian Journal of Geophysics
Volume 8, Issue 2
September 2014
Pages 110-122

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