Thesis supervisor: Gyula Tóth
Location of studies (in Hungarian): BME Általános- és Flsőgeodézia Tanszék Abbreviation of location of studies: AF
Description of the research topic:
Gravity field and geoid determination with cm accuracy has became a key issue in heighting with the ubiquitous GNSS systems. Before the success of space gravity gradiometry local gravity field modeling was necessarily based almost exclusively on surface gravity data, which are heterogeneously distributed both in space and time. Considering several decades old surface gravimetric, gradiometric (torsion balance), leveling and vertical deflection data as well as recent crustal movements of more than one dm detected in the Great Hungarian Plains, there is no reason to expect centimeter accuracy in geoid determination.
The GOCE mission of ESA has significantly contributed to gravity field determination both in accuracy and resolution. Full 42 months of gradiometric data of the mission were made available for scientists by the ESA, hence analysis and use of these data is in the forefront of international research. There are more than half of a million gravity gradient data at 100,000 points that are almost homogeneously distributed over the wider area of Hungary. These up-to-date measurements make an unique opportunity for us to produce an accurate gravity field model, however, no attempt has yet been made for that purpose. Only an indirect use of those data has been made through geopotential models.
GOCE data can be utilized directly in gravity field determination through a large inverse problem. Modeling of the gravity field is possible through spatially localized base functions. Key issues of this inversion are the number of base functions, regularization of the solution and proper weighting of observations.
Main points to be addressed and tasks to be completed:
- Selection of GOCE measurements over the wider area of Hungary, data quality check and analysis
- Study of the formulas of inversion by radial base functions and evaluation of references in the literature. Development of a modeling software that can handle all available data (GNSS/leveling, gravity, deflection of the vertical, surface and space gravity gradiometry). Software testing and validation
- Data reduction by geopotential models and test computations with different regularization schemes
- Evaluation and analysis of the solutions and comparison with earlier gravity field models
Number of students who can be accepted: 1
Deadline for application: 2022-12-20
2024. IV. 17. ODT ülés Az ODT következő ülésére 2024. június 14-én, pénteken 10.00 órakor kerül sor a Semmelweis Egyetem Szenátusi termében (Bp. Üllői út 26. I. emelet).
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