39 Result(s)
within
Bernhard Heck
English
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Chapter and Conference Paper
Evaluation of the Recent African Gravity Databases V2.x
In the framework of the activities of the IAG Sub-Commission on the gravity and geoid in Africa, a recent set of gravity databases has been established. They are namely: AFRGDB_V2.0 and AFRGDB_V2.2. The AFRGDB...
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Article
Open AccessExternal gravitational field of a homogeneous ellipsoidal shell: a reference for testing gravity modelling software
There are numerous applications in geodesy and other geo-sciences in which the gravitational potential effect or other functions of the potential are computed by forward modelling from a given mass distributio...
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Article
Assessment of point-mass solutions for recovering water mass variations from satellite gravimetry
Previous studies have shown the feasibility of point-mass modellings for deriving terrestrial water storage (TWS) from the harmonic solutions of the Gravity Recovery And Climate Experiment (GRACE) mission at r...
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Chapter and Conference Paper
A Precise Geoid Model for Africa: AFRgeo2019
In the framework of the IAG African Geoid Project, an attempt towards a precise geoid model for Africa is presented in this investigation. The available gravity data set suffers from significantly large data g...
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Article
Effect of great lakes on gravity reduction and geoid determination caused by unclassified DTMs: case study for Lake Victoria, Africa
The determination of the gravimetric geoid is based on the magnitude of gravity observed at the topographic surface of the Earth. In order to satisfy Laplace’s equation, the masses between the surface of the E...
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Article
The New AFRGDB_V2.2 Gravity Database for Africa
The primary task of the IAG Sub-Commission on Gravity and Geoid in Africa is the development of the vertical reference surface (the geoid) for the entire African continent. For the practical solution of this b...
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Article
Comparison of two different approaches for computing the gravitational effect of a tesseroid
Forward modelling in the space domain is a very important task in geodesy and other geosciences. From topographical or isostatic information in the form of digital terrain model (DTM) and density model, the ef...
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Chapter and Conference Paper
AFRGDB_V2.0: The Gravity Database for the Geoid Determination in Africa
The available gravity data set for Africa consists of land point gravity data as well as shipborne and altimetry derived gravity anomalies data, but suffers from a lot of significant large gaps. The establishm...
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Chapter and Conference Paper
Evaluation of the African Gravity Database AFRGDB_V1.0
The AFRGDB_V1.0 gravity database has been generated in 2015 from a set of land, shipborne and altimetry-derived gravity anomalies. This gravity data set had significantly large gaps especially on land. Recentl...
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Article
Estimating and assessing Galileo satellite fractional cycle bias for PPP ambiguity resolution
Due to the rapid deployment of the Galileo constellation, Galileo is now able to contribute to GNSS precise point positioning (PPP) ambiguity resolution (AR) with 17 operational satellites as of December 2017....
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Article
Estimating satellite phase fractional cycle biases based on Kalman filter
Phase fractional cycle biases (FCBs) originating from satellites and receivers destroy the integer nature of PPP carrier phase ambiguities. To achieve integer ambiguity resolution of PPP, FCBs of satellites ar...
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Article
Improved time-differenced cycle slip detect and repair for GNSS undifferenced observations
GNSS undifferenced signal processing, in which the individual signal of each frequency is treated as independent observable, has drawn increasing interest in GNSS community. However, undifferenced signal proce...
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Article
On High-Frequency Topography-Implied Gravity Signals for a Height System Unification Using GOCE-Based Global Geopotential Models
National height reference systems have conventionally been linked to the local mean sea level, observed at individual tide gauges. Due to variations in the sea surface topography, the reference levels of these...
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Article
The Rock–Water–Ice Topographic Gravity Field Model RWI_TOPO_2015 and Its Comparison to a Conventional Rock-Equivalent Version
RWI_TOPO_2015 is a new high-resolution spherical harmonic representation of the Earth’s topographic gravitational potential that is based on a refined Rock–Water–Ice (RWI) approach. This method is characterize...
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Article
Open AccessCorrections to “A comparison of the tesseroid, prism and point-mass approaches for mass reductions in gravity field modelling” (Heck and Seitz, 2007) and “Optimized formulas for the gravitational field of a tesseroid” (Grombein et al., 2013)
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Chapter and Conference Paper
Height System Unification Based on the Fixed GBVP Approach
In general, any national or regional height reference system is related to an individual vertical datum, defined by one or several tide gauges. The discrepancies of these local vertical datums cause height dat...
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Chapter and Conference Paper
Tailored Reference Geopotential Model for Africa
In the framework of the African Geoid Project, the currently available gravity data set contains many significant gaps allover the continent. A possible way to fill in these gaps before the geoid computation p...
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Chapter and Conference Paper
An Inventory of Surface Movements in the Upper Rhine Graben Area, Southwest Germany, from SAR-Interferometry, GNSS and Precise Levelling
Recent surface movements in the Upper Rhine Graben (URG) area are investigated with geodetic techniques. Line of sight (LOS) displacement rates from SAR interferometry (InSAR), horizontal and vertical rates fr...
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Chapter and Conference Paper
Establishment of the Gravity Database AFRGDB_V1.0 for the African Geoid
In the framework of the IAG African Geoid Project it is needed to have a uniform gridded gravity data set to compute the geoid using Stokes’ integral in the frequency domain by 1-D FFT technique. The available...
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Chapter and Conference Paper
Analysis of the Discrepancies Between the Brazilian Vertical Reference Frame and GOCE-Based Geopotential Model
In this study we estimate the discrepancies between the Brazilian vertical network, realized in the system of normal-orthometric heights, and a global quasi-geoid model. We consider the GNSS-leveling and a glo...
