Connection of Local Vertical Reference Systems to Brazilian Geodetic System based on a Global Vertical Reference System

Global Geopotential Models (GGMs), specially those provided by GOCE mission, associated with Digital Elevation Models (DEMs) with increasingly higher resolutions, has enable new alternatives for obtaining physical heights. The purpose of this work is the realization of a local height system, in a region with poor data from the Brazilian Geodetic System (BGS), and link it to a Global Vertical Reference System (GVRS). The GGMs were validated using GPS/leveling stations. The omission error of GGMs was modeled by using the Residual Terrain Model (RTM) technique. The geopotential numbers were obtained through a simplified solution of the Geodetic Boundary Value Problem (GBVP) in a fixed approach. The study area is the Amapá state, whose altitudes are linked with the Brazilian Vertical Datum of Santana (BVD-S), and for validation of GGMs some stations linked to Brazilian Vertical Datum of Imbituba (BVD-I) in the state of Pará were also used. As a result, geopotential numbers and heights with physical meaning were obtained. In the validation of the models, RTM technique had no significant influence. With the GGM from GOCE, GO_CONS_SPW_R4, it was obtained that the network linked to BVD-S is 1,30m above the network linked to BVD-I.

Keywords:
Global Geopotential Models; Global Vertical Reference System; Geodetic Boundary Value Problem; RTM