Analysis of GOCE Omission Error and Its Contribution to Vertical Datum Offsets in Greece and Its Islands

2017 ◽  
pp. 143-148 ◽  
Author(s):  
Martin Willberg ◽  
Thomas Gruber ◽  
Georgios S. Vergos
Keyword(s):  
Omission Error ◽  
Vertical Datum

scholarly journals Intercontinental height datum connection with GOCE and GPS-levelling data

2012 ◽  
Vol 2 (4) ◽  
pp. 270-280 ◽  
Author(s):  
T. Gruber ◽  
C. Gerlach ◽  
R. Haagmans
Keyword(s):  
Gravity Field ◽  
Ocean Circulation ◽  
Omission Error ◽  
Commission Error ◽  
Optimal Point ◽  
Point Distribution ◽  
Gravity Field Model ◽  
Vertical Datum ◽  
Height Datum ◽  
The Mean

AbstractIn this study an attempt is made to establish height system datum connections based upon a gravity field and steady-state ocean circulation explorer (GOCE) gravity field model and a set of global positioning system (GPS) and levelling data. The procedure applied in principle is straightforward. First local geoid heights are obtained point wise from GPS and levelling data. Then the mean of these geoid heights is computed for regions nominally referring to the same height datum. Subsequently, these local mean geoid heights are compared with a mean global geoid from GOCE for the same region. This way one can identify an offset of the local to the global geoid per region. This procedure is applied to a number of regions distributed worldwide. Results show that the vertical datum offset estimates strongly depend on the nature of the omission error, i.e. the signal not represented in the GOCE model. For a smooth gravity field the commission error of GOCE, the quality of the GPS and levelling data and the averaging control the accuracy of the vertical datum offset estimates. In case the omission error does not cancel out in the mean value computation, because of a sub-optimal point distribution or a characteristic behaviour of the omitted part of the geoid signal, one needs to estimate a correction for the omission error from other sources. For areas with dense and high quality ground observations the EGM2008 global model is a good choice to estimate the omission error correction in theses cases. Relative intercontinental height datum offsets are estimated by applying this procedure between the United State of America (USA), Australia and Germany. These are compared to historical values provided in the literature and computed with the same procedure. The results obtained in this study agree on a level of 10 cm to the historical results. The changes mainly can be attributed to the new global geoid information from GOCE, rather than to the ellipsoidal heights or the levelled heights. These historical levelling data are still in use in many countries. This conclusion is supported by other results on the validation of the GOCE models.

scholarly journals Estimation of Vertical Datum Parameters Using the GBVP Approach Based on the Combined Global Geopotential Models

2020 ◽  
Vol 12 (24) ◽  
pp. 4137
Author(s):  
Panpan Zhang ◽  
Lifeng Bao ◽  
Dongmei Guo ◽  
Lin Wu ◽  
Qianqian Li ◽  
...  
Keyword(s):  
Gravity Field ◽  
Ocean Circulation ◽  
Omission Error ◽  
Practical Implementation ◽  
Geopotential Model ◽  
Weighting Method ◽  
The North ◽  
Main Challenge ◽  
Vertical Datum ◽  
Local Vertical Datum

Unification of the global vertical datum has been a key problem to be solved for geodesy over a long period, and the main challenge for a unified vertical datum system is to determine the vertical offset between the local vertical datum and the global vertical datum. For this purpose, the geodetic boundary value problem (GBVP) approach based on the remove-compute-restore (RCR) technique is used to determine the vertical datum parameters in this paper. In the RCR technique, a global geopotential model (GGM) is required to remove and restore the long wavelengths of the gravity field. The satellite missions of the GRACE (Gravity Recovery and Climate Experiment) and GOCE (Gravity field and steady-state Ocean Circulation Exploration) offer high accuracy medium–long gravity filed information, but GRACE/GOCE-based GGMs are restricted to medium–long wavelengths because the maximum degree of their spherical harmonic representation is limited, which is known as an omission error. To compensate for the omission error of GRACE/GOCE-based GGM, a weighting method is used to determine the combined GGM by combining the high-resolution EGM2008 model (Earth Gravitational Model 2008) and GRACE/GOCE-based GGM to effectively bridge the spectral gap between satellite and terrestrial data. An additional consideration for the high-frequency gravity signals is induced by the topography, and the residual terrain model (RTM) is used to recover the omission errors effect of the combined GGM. In addition, to facilitate practical implementation of the GBVP approach, the effects of the indirect bias term, the spectral accuracy of the GGM, and the systematic levelling errors and distortions in estimations of the vertical datum parameters are investigated in this study. Finally, as a result of the GBVP solution based on the combined DIR_R6/EGM2008 model, RTM, and residual gravity, the geopotential values of the North American Vertical Datum of 1988 (NAVD88), the Australian Height Datum (AHD), and the Hong Kong Principal Datum (HKPD) are estimated to be equal to 62636861.31 ± 0.96, 62653852.60 ± 0.95 and 62636860.55 ± 0.29 m2s−2, respectively. The vertical offsets of NAVD88, AHD, and HKPD with respect to the global geoid are estimated as −0.809 ± 0.090, 0.082 ± 0.093, and −0.731 ± 0.030 m, respectively.

scholarly journals Estimating Canadian vertical datum offsets using GNSS/levelling benchmark information and GOCE global geopotential models

2012 ◽  
Vol 2 (4) ◽  
pp. 257-269 ◽  
Author(s):  
T. Hayden ◽  
B. Amjadiparvar ◽  
E. Rangelova ◽  
M.G. Sideris
Keyword(s):  
High Resolution ◽  
Geoid Height ◽  
Omission Error ◽  
Control Network ◽  
Commission Error ◽  
Vertical Control ◽  
Geopotential Models ◽  
Vertical Datum ◽  
Local Vertical Datum ◽  
Omission Errors

AbstractThe performance of GOCE-based geopotential models is assessed for the estimation of offsets for three regional vertical datums in Canada with respect to a global equipotential surface using the GNSS benchmarks from the first-order vertical control network. Factors that affect the computed value of the local vertical datum offset include the GOCE commission and omission errors, measurement errors, the configuration of the network of GNSS/levelling benchmarks, and systematic levelling errors and distortions propagated through the vertical control network. Among these various factors, the effect of the GOCE omission error on the datum offsets is investigated by extending the models with the high resolution gravity field model EGM2008 and by means of Canada’s official high resolution geoid model CGG2010. The effect of the GOCE commission error in combination with errors from the GNSS/levelling data is also examined, in addition to the effect of systematic levelling errors. In Canada, the effect of the GOCE omission error is at the dm-level when computing local vertical datum offsets. The effect of including accuracy information for the GNSS/levelling data and the GOCE geoid heights can be up to 4 cm over the Canadian mainland and at the dm-level for island regions. Lastly, the spatial tilts found in the levelling network can be modelled with a 2-parameter bias corrector model, which reduces the RMS of the adjusted geoid height differences by 4 cm when compared to the RMS of adjusted geoid height differences computed without the use of a bias corrector model. Thus, when computing local vertical datum offsets in Canada, it is imperative to account for GOCE commission and omission errors, ellipsoidal and levelling height errors, as well as the systematic levelling errors of the vertical control network.

Vertical Datum Transformations across the Australian Littoral Zone

2015 ◽  
Vol 31 (1) ◽  
pp. 119 ◽  
Author(s):  
Jessica H. Keysers ◽  
Nathan D. Quadros ◽  
Philip A. Collier
Keyword(s):  
Littoral Zone ◽  
Vertical Datum

Local Effects in the Brazilian Vertical Datum

2002 ◽  
pp. 102-107 ◽  
Author(s):  
S. R. C. de Freitas ◽  
S. H. S. Schwab ◽  
E. Marone ◽  
A. O. Pires ◽  
R. Dalazoana
Keyword(s):  
Local Effects ◽  
Vertical Datum
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