Different topographic reduction methods in practical gravimetric geoid determination
Three different topographic reduction methods in geoid determination were investigated. The first method is the classical Helmert second method of condensation yielding the geoid, the second is the Residual Terrain Model (RTM) method yielding the quasigeoid and the third is the Rudzki inversion meth...
| Autores: | , , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2002 |
| País: | Argentina |
| Recursos: | Universidad Nacional de La Plata |
| Repositorio: | SEDICI (UNLP) |
| Idioma: | inglés |
| OAI Identifier: | oai:sedici.unlp.edu.ar:10915/139999 |
| Acesso em linha: | http://sedici.unlp.edu.ar/handle/10915/139999 |
| Access Level: | acceso abierto |
| Palavra-chave: | Geofísica Helmert RTM Rudzki Geoid Quasigeoid Direct terrain effects Indirect effects Geoide Casi geoide Efectos directos sobre el terreno Efectos indirectos |
| Resumo: | Three different topographic reduction methods in geoid determination were investigated. The first method is the classical Helmert second method of condensation yielding the geoid, the second is the Residual Terrain Model (RTM) method yielding the quasigeoid and the third is the Rudzki inversion method. The different types of indirect effects (indirect effect on gravity and indirect effect on geoid) in Helmert's method were also investigated. All three methods use the remove-restore technique and the EGM96 geopotential model as the reference gravity field. A mountainous area, ranging from 32°S to 42°S in latitude and 72°W to 68°W in longitude, was chosen as test area. The area was selected due to its high topography, with a maximum height of 6795 meters and a mean height of 1188 meters, and due to the existence of GPS/leveling points in three different networks. The topography in the test area is-represented by a digital terrain model (DTM) with a grid spacing of 1 km x 1 km. Another test was carried out in a flat area with denser data coverage. The external accuracy of the three gravimetric geoids was evaluated by comparing them to undulations derived from GPS/leveling. |
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