New Gravimetric Infrastructure in Southeast Brazil: From Absolute Gravity Network to a Geoid Model

Abstract

The study and understanding of the geodynamic aspects on the planet require global geodetic references with an order of accuracy better than the magnitude of the effects and with consistency and reliability. In this sense, this paper aims to present the new gravimetric infrastructure in the Brazilian southeast. A set of 22 absolute gravity stations were measured and materialized in the region. Additionally, gravity densification was carried out throughout the region aiming at a quasigeoid model. In the last decade, almost 3,000 points were collected. The model was computed by the least-squares collocation methodology using a recent geopotential model in the long- wavelength component and recent digital terrain model to compute the terrain correction. The quasigeoid model was validated with 136 global navigation satellite system (GNSS)/leveling stations and the RMS is 0.25 m. Furthermore, GNSS/leveling stations were compared with five recent geopotential models and the mean RMS difference was 0.28 m. Absolute and relative gravity stations will improve the national geodetic infrastructure, especially concerning the International Height Reference Frame and the International Gravity Reference Frame.