The determination of the Earth’s gravity field is the main goal of the dedicated gravity field missions CHAMP, GRACE and GOCE. The gravity field comprises always a static part and a much smaller timevariable one in the order of millimeters to centimeters, if expressed in geoid heights. As the measurements always consist of both parts, one has to separate them to get a highly accurate static fie...

the earth’s gravity field dedicated missions, champ, grace and goce have opened up a new era for the study of the earth’s gravity field. the missions measure different functionals on the earth’s gravitational potential which are represented in terms of the stokes coefficients or the so-called geopotential models. the mapping process of the observations into the coefficients is called recovery o...

one of the most valuable and important application of artificial satellites in geodetic sciences is recovery of the earth's gravity field. orbits of satellites either gravimetric or nongravimetric are analyzed to improve the earth's gravity field. gravimetric satellites are launched at low altitudes to observe gravity field in more detail. grace twin satellites are the second spacecra...

the recent dedicated satellite gravimetry missions have provided huge amount of high quality gravity data with global coverage. from computational point of view, estimation of the unknown gravity field parameters is a highly demanding task due to the sheer number of observations and the unknown coefficients. different computational schemes have been proposed to tackle the problem. since the ear...

NASA dedicated over 20 shuttle missions to microgravity research as a primary payload, and many more missions carried microgravity research experiments as secondary payloads. The space agency’s microgravity research strived to increase understanding of the effects of gravity on biological, chemical, and physical systems. Living systems benefited as well. Cells, as they adapted to microgravity, ...

We introduce a linearized bi-metric theory of gravity with two metrics. The metric gαβ describes null hypersurfaces of the gravitational field while light moves on null hypersurfaces of the optical metric ḡαβ. Bi-metrism naturally arises in vector-tensor theories with matter being non-minimally coupled to gravity via long-range vector field. We derive explicit Lorentz-invariant solution for a l...

Global models of the Earth’s gravitational field can be divided among three primary classes: satellite-only, combined and tailored models. Some of the current deficiencies in some of these models will be outlined using examples over Australia. The new dedicated satellite gravity field missions (e.g., GRACE, CHAMP and GOCE) will make significant improvements to the long-wavelength, satellite-der...

Satellite data that are used to model the global gravity field of the Earth are typically corrupted by correlated noise, which can be related to a frequency dependence of the data accuracy. We show an opportunity to take such noise into account by using a proper noise covariance matrix in the estimation procedure. If the dependence of noise on frequency is not known a priori, it can be estimate...

Satellite radar altimetry collected during a number of geodetic missions has provided new understanding the topography and tectonics deep oceans. As altimeter performance coverage improves, smaller structures are revealed. Here we investigate contribution six that have been placed into mapping phases for more than one year. Two types evaluations performed. We first compare composite (all altime...

Recently Ciufolini has suggested to use the perigee of the proposed LARES/WEBER-SAT satellite in order to measure the secular precession which would be induced on such Keplerian orbital element by a weak-field modification of gravity occurring in some Brane-World scenarios put forth by Dvali. This precession would amount to 0.04 milliarcseconds per year for LARES. In this paper we show that, ac...