Abstract:As the CHAMP has been launched as the first of the gravity satellites of the 2000s, its processing has been a real challenge for the geodetic community. Several methods have been developed for gravity field modelling based on different theoretical backgrounds. In this study the feasibility of the direct use of the Newtonian equation of motion has been studied. Then numerical results for 2 years of CHAMP observations are presented. Though the method failed to provide the best CHAMPonly gravity field model, it h… Show more
“…[5,14,15]). ESA's Gravity field and steady-state Ocean Circulation Explorer is the first dedicated satellite mission that employs gravity gradiometry to determine and refine the long-and especially the medium-wavelength components of the Earth's gravitational field.…”
With the advantage of satellite gravity gradiometry (SGG) high standard global gravity determination could attain in the static part of the gravitational field. This paper presents the validation of the first and second generation GOCE-only models using terrestrial data sets in Hungary. GOCE global geopotential models (GGM) are consistent models with global coverage in sense that GGMs have been compiled utilizing measurements refer to short time period. Besides GOCE-based GGMs satellite only GRACE models were evaluated to assess the improvements by GOCE observations with respect to GRACE in gravity field determination. EGM2008 as the state-of-the-art model and SRTM3 elevation model were applied to provide that measurements involving Hungarian data sets and model derived gravity field functionals have almost the same spectral content. Results with GPS-levelling and gravity data support that there is an improvement in the determination of medium-wavelength parts of the gravitational field with GOCE models. Although vertical deflections characterize the short-wave part of the gravity field, they are also capable to sense the advancement of SGG observations. Our experiences show that torsion balance measurements depict the fine structure of the gravity field, and hence they are not adequate in low-degree GGM validation.
“…[5,14,15]). ESA's Gravity field and steady-state Ocean Circulation Explorer is the first dedicated satellite mission that employs gravity gradiometry to determine and refine the long-and especially the medium-wavelength components of the Earth's gravitational field.…”
With the advantage of satellite gravity gradiometry (SGG) high standard global gravity determination could attain in the static part of the gravitational field. This paper presents the validation of the first and second generation GOCE-only models using terrestrial data sets in Hungary. GOCE global geopotential models (GGM) are consistent models with global coverage in sense that GGMs have been compiled utilizing measurements refer to short time period. Besides GOCE-based GGMs satellite only GRACE models were evaluated to assess the improvements by GOCE observations with respect to GRACE in gravity field determination. EGM2008 as the state-of-the-art model and SRTM3 elevation model were applied to provide that measurements involving Hungarian data sets and model derived gravity field functionals have almost the same spectral content. Results with GPS-levelling and gravity data support that there is an improvement in the determination of medium-wavelength parts of the gravitational field with GOCE models. Although vertical deflections characterize the short-wave part of the gravity field, they are also capable to sense the advancement of SGG observations. Our experiences show that torsion balance measurements depict the fine structure of the gravity field, and hence they are not adequate in low-degree GGM validation.
“…The rotation involves apparent accelerations to the equation. These are the last three terms of the right-hand side, which are the centrifugal, Coriolis and Euler accelerations, respectively (for more details see [7]). …”
Classical numerical integration methods have been tested for determining the orbit of most recent Low Earth Orbiter (hereafter LEO) satellites. In general, numerical integration techniques for orbit determination are commonly used to fill the gap between two discrete, observed epochs. In this study orbits have been determined using the EGM96 gravity model by the Euler, Runge-Kutta, Bulirsch-Stoer and Adams-Moulton numerical integration techniques among others. This analysis is performed for a LEO, the GOCE, and for medium altitude satellite, one GPS satellite. The orbits are integrated under different assumptions on the roughness of the force model, considering effects of the ellipticity, high order gravity and non-static Earth generated accelerations on the orbit. Keywords orbit integration · LEO · ellipticity · high order gravity · tides · air drag Acknowledgement This work is connected to the scientific program of the "Development of quality-oriented and harmonized R+D+I strategy and functional model at BME" project.
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