GOCE Variance and Covariance Contribution to Height System Unification

2017 ◽  
pp. 157-164 ◽  
Author(s):  
V. D. Andritsanos ◽  
V. N. Grigoriadis ◽  
D. A. Natsiopoulos ◽  
G. S. Vergos ◽  
T. Gruber ◽  
...  
Keyword(s):  
Height System ◽  
Height System Unification

Clock networks for height system unification: a simulation study

2018 ◽  
Vol 216 (3) ◽  
pp. 1594-1607 ◽  
Author(s):  
Hu Wu ◽  
Jürgen Müller ◽  
Claus Lämmerzahl
Keyword(s):  
Simulation Study ◽  
Clock Networks ◽  
Height System ◽  
Height System Unification

scholarly journals Towards worldwide height system unification using ocean information

2012 ◽  
Vol 2 (4) ◽  
pp. 302-318 ◽  
Author(s):  
P.L. Woodworth ◽  
C.W. Hughes ◽  
R.J. Bingham ◽  
T. Gruber
Keyword(s):  
North Atlantic ◽  
Pacific Coast ◽  
Data Sets ◽  
Dynamic Topography ◽  
Model Accuracy ◽  
Geoid Model ◽  
Height System ◽  
The Mean ◽  
Height System Unification

AbstractWe describe the application of ocean levelling to worldwide height system unification. The study involves a comparison of ‘geodetic’ and ‘ocean’ approaches to determination of the mean dynamic topography (MDT) at the coast, from which confidence in the accuracy of stateof- the-art ocean and geoid models can be obtained. We conclude that models are consistent at the sub-decimetre level for the regions that we have studied (North Atlantic coastlines and islands, North American Pacific coast and Mediterranean). That level of consistency provides an estimate of the accuracy of using the ocean models to provide an MDT correction to the national datums of countries with coastlines, and thereby of achieving unification. It also provides a validation of geoid model accuracy for application to height system unification in general. We show how our methods can be applied worldwide, as long as the necessary data sets are available, and explain why such an extension of the present study is necessary if worldwide height system unification is to be realised.

scholarly journals Towards worldwide height unification using ocean information

2015 ◽  
Vol 365 ◽  
pp. 11-15
Author(s):  
P. L. Woodworth ◽  
C. W. Hughes
Keyword(s):  
North America ◽  
Sea Level ◽  
Tide Gauge ◽  
European Space Agency ◽  
Mean Sea Level ◽  
Space Agency ◽  
Height System ◽  
Ocean Models ◽  
Height System Unification

Abstract. This paper describes how we are contributing to worldwide height system unification (WHSU) by using ocean models together with sea level (tide gauge and altimeter) information, geodetic (GPS and levelling) data, and new geoid models based on information from the GRACE and GOCE gravity missions, to understand how mean sea level (MSL) varies from place to place along the coast. For the last two centuries, MSL has been used to define datums for national levelling systems. However, there are many problems with this. One consequence of WHSU will be the substitution of conventional datums as a reference for heights with the use of geoid, as the only true "level" or datum. This work is within a number of GOCE-related activities funded by the European Space Agency. The study is focused on the coastlines of North America and Europe where the various datasets are most copious.

Accuracy Assessment of Recent High-Degree Global Geopotential Models Using Geodetic Control Points and Terrestrial Gravity Data in Turkey

2021 ◽  
Author(s):  
Muhammed Raşit Çevikalp ◽  
Bihter Erol ◽  
Bilal Mutlu ◽  
Serdar Erol
Keyword(s):  
Gravity Data ◽  
Geopotential Model ◽  
Geoid Model ◽  
Terrestrial Gravity ◽  
Practical Applications ◽  
Geopotential Models ◽  
Vertical Datum ◽  
Height System ◽  
Orthometric Heights ◽  
Height System Unification

<p>The maintenance of leveling benchmark is both laborious and costly due to distortions caused by geodynamic activities and local deformations. It is necessary to realize geoid-based vertical datum, which also enables calculation from ellipsoidal heights obtained from GNSS to orthometric heights that have physical meaning. It can be considered as an important step for height system unification as it eliminates the problems stem from the conventional vertical datum. The ongoing height modernization efforts in Turkey focus to improve quality and coverage of the gravity data, eliminate errors in existing terrestrial gravity measurements in order to achieve a precise geoid model. Accuracy of the geopotential model is crucial while realizing a geoid model based vertical datum as well as unifying the regional height systems with the International Heights Reference System. In this point of view, we assessed the accuracies of recently released global geopotential models including XGM2019e_2159, GECO, EIGEN-6C4, EGM2008, SGG-UGM-1, EIGEN-6C3stat, and EIGEN-6C2 using high order GNSS/leveling control benchmarks and terrestrial gravity data in Turkey. The reason for choosing these models in the validations is their relatively higher spatial resolutions and improved accuracies compared to other GGMs in published validation results with globally distributed terrestrial data. The GNSS/leveling data used in validations include high accuracy GNSS coordinates in ITRF datum with co-located Helmert orthometric heights in regional vertical datum. 100 benchmarks are homogeneously distributed in the country with the benchmarks along the coastlines. In addition, the terrestrial gravity anomalies with 5 arc-minute resolution were also used in the tests. In order to have comparable results, residual terrain effect has been restored to the GGM derived parameters. Numerical tests revealed significant differences in accuracies of the tested GGMs. The most accurate GGM has the comparable performance with official regional geoid model solutions in Turkey. The drawn results in the study were interpreted and discussed from practical applications and height system unification points in conclusion.</p>

scholarly journals Preliminary results of GOCE-based height system unification between Greece and Turkey over marine and land areas

2017 ◽  
Vol 53 (1) ◽  
pp. 61-79 ◽  
Author(s):  
Georgios S. Vergos ◽  
Bihter Erol ◽  
Dimitrios A. Natsiopoulos ◽  
Vassilios N. Grigoriadis ◽  
Mustafa Serkan Işık ◽  
...  
Keyword(s):  
Preliminary Results ◽  
Height System ◽  
Height System Unification

Evaluation of GOCE/GRACE GGMs Over Attica and Thessaloniki, Greece, and Wo Determination for Height System Unification

2015 ◽  
pp. 101-109 ◽  
Author(s):  
G. S. Vergos ◽  
V. D. Andritsanos ◽  
V. N. Grigoriadis ◽  
V. Pagounis ◽  
I. N. Tziavos
Keyword(s):  
Height System ◽  
Height System Unification
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