PHYSICAL CONNECTION BETWEEN BVRF SEGMENTS BASED ON LEVELING ASSOCIATED WITH GRAVIMETRY

Andrea Santacruz Jaramillo,Sílvio Rogério Correia De Freitas,Roberto Teixeira Luz

doi:10.1590/s1982-21702019000100006

Abstract

Abstract Considering the efforts to establish Global Reference Systems linked to the geopotential space, new alternatives are sought to address the problems found in the classic national vertical networks. The Brazilian Vertical Reference Frame (BVRF) was materialized in two different segments with independent datums (Imbituba and Santana tide gauges) due to the terrain difficulties for conventional leveling. The 2018 BVRF realization, in the geopotential space, still remains without interoperability between its segments. We analyze alternatives for physical connection based on the new precepts of the International Association of Geodesy (IAG) involving the geopotential space. Some proposed solutions for physical connection based on GPS leveling associated with gravimetry are presented. These solutions were developed with the aim of evidencing the discrepancy between the two BVRF segments, now carried out in terms of geopotential numbers and normal heights. The results indicate differences ranging from about 45 cm to 140 cm between the two segments depending on the strategy employed. Comparisons with previous determinations based on indirect strategies and involving previous BVRF realizations are made.

Highlights

Earth System change monitoring activities demand accuracy and reliability in realized spatial position referencing
In accordance with the conventions for International Height Reference System (IHRS) established in International Association of Geodesy (IAG) Resolution 1/2015 (IAG 2015a), the global reference zero level is that associated with the equipotential surface with the conventional value W0 = 62 636 853,4 m2s‐2 (Sánchez et al 2016)
Because the characteristics of the two segments of leveling used in the connection are quite different (GPS + gravimetry in segment 1 and spirit leveling + gravimetry + sparse GPS in segment 2) some strategies were developed for testing the approach used

Summary

Introduction

Earth System change monitoring activities demand accuracy and reliability in realized spatial position referencing. The requirements for quantifying the dynamical process within the planet are strongly dependent on modeling the mass flux inside the Earth’s System based on changes in its geometry, rotation and gravity field (Kutterer, Neilan, and Bianco 2012) In this sense, the quality of Geodetic Reference Systems (GRS), involving positions, gravity, and geodynamical aspects, must support accuracy requirements tending to 1 ppb in the forthcoming years (Plag et al 2009). GGOS Theme 1 - Global Unified Height System - was established in 2010 as a fundamental element for integrating geometry and gravity field aspects These aspects were reinforced by United Nations General Assembly Resolution A/RES/69/266 in February 2015. IBGE’s strategies and current activities in cooperation with the Federal University of Paraná (UFPR) for solving the connections between the two BVRF segments in the geopotential space and the results obtained are presented in this paper

Amazonian Connection Area and description of involved Database

Method

Database Analysis

Methodology and Results

Proposed Solutions