DETERMINISTICALLY-MODIFIED INTEGRAL ESTIMATORS OF GRAVITATIONAL TENSOR

Mohsen Romeshkani,Mehdi Eshagh

doi:10.1590/s1982-217020150001000012

Mohsen Romeshkani, Mehdi Eshagh

Open Access

https://doi.org/10.1590/s1982-217020150001000012

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Abstract

The Earth's global gravity field modelling is an important subject in Physical Geodesy. For this purpose different satellite gravimetry missions have been designed and launched. Satellite gravity gradiometry (SGG) is a technique to measure the second-order derivatives of the gravity field. The gravity field and steady state ocean circulation explorer (GOCE) is the first satellite mission which uses this technique and is dedicated to recover Earth's gravity models (EGMs) up to medium wavelengths. The existing terrestrial gravimetric data and EGM scan be used for validation of the GOCE data prior to their use. In this research, the tensor of gravitation in the local north-oriented frame is generated using deterministically-modified integral estimators involving terrestrial data and EGMs. The paper presents that the SGG data is assessable with an accuracy of 1-2 mE in Fennoscandia using a modified integral estimatorby the Molodensky method. A degree of modification of 100 and an integration cap size of for integrating terrestrial data are proper parameters for the estimator.

Highlights

Satellite gravity gradiometry (SGG) is a space method for recovering the Earth’s gravity field from the second-order derivatives of the field
Delivering Earth’s gravity models (EGMs) with higher resolution than those recovered from former satellite gravimetry techniques is expected from these data
gravity field and steady-state ocean circulation explorer (GOCE) measured the second-order derivatives of gravitational potential, but since our goal is to use the gravity anomalies at sea level, we consider the derivatives of the disturbing potential (T)

Summary

INTRODUCTION

Satellite gravity gradiometry (SGG) is a space method for recovering the Earth’s gravity field from the second-order derivatives of the field. When such a model is used, higher degrees and orders of EGMs should be taken into account and the recent ones seem to be able to remove the greater part of the systematic errors In their regional approach, they concluded that the bias of the SGG data can be recovered very well using LSC. D) The present work This paper is very similar to the work presented by Eshagh and Romeshkani (2011) with the difference of investigating the deterministic methods of modifying the integral estimatorsfor generation of the SGG data instead of the stochastic ones. Wolf (2007) has done some studies about validation of the SGG data using integral formulae modified deterministically, but she considered limited number of methods for this goal. We consider methods of Molodensky (1962), Vanicek-Kleusberg (1987), Meissl (1971), Heck and Grunningar (1987), Featherstone et al, (1998), Wong and Gore (1969) methods for modifying the integral estimators for generating the SGG data from the gravity anomalies at sea level

SATELLITE GRAVITY GRADIOMETRY OBSERVABLES

Δg n λ2

NUMERICAL INVESTIGATIONS

CONCLUDING REMARKS