In this paper we use, in a very preliminary way, the recently released EIGEN2 Earth gravity model, which is based on six months of data of CHAMP only, in order to reassess the systematic error due to the mismodelling in the even zonal harmonics of geopotential which represents one of the major sources of systematic errors in the LAGEOS–LAGEOS II Lense–Thirring experiment involving the nodes of ...

AGlobal Vertical Datum (GVD) is naturally defined by the geoid, and there is a well-established consensus to adopt Gauss-Bessel-Listing's definition of the geoid (i.e. as being the level surface of the Earth's gravity field that best fits the undisturbed sea level). Themain problem in defining the geoid is therefore to fix its constant geopotential (W0). Nevertheless, this definition can be int...

In this paper we try to suggest a possible novel method to determine some selected even zonal harmonics Jl of the Earth’s geopotential. Time series some years long of suitably linearly combined residuals of some Keplerian orbital elements of certain existing geodetic SLR satellites would be examined and corrections ∆Jl for the even zonals which we are interested in would be obtained. A CHAMP/GR...

The inner core wobble (ICW) is a normal mode of rotation of the inner core (IC) relative to the mantle predicted theoretically. While many papers have been devoted to its theoretical formulation, no attempt of its detection has been published in the literature. In this work, we first give a preliminary formulation for the variations of gravity and geopotential coefficients associated with the I...

Two approaches to determining the Earth’s external potential field by using GPS technique are proposed. The first one is that the relation between the geopotential difference and the light signal’s frequency shift, between two separated points, is applied. The second one is that the spherical harmonic expansion series and a new technique dealing with the “downward continuation” problem are appl...

In this paper, an approach is proposed for relative state estimation for satellites in formation flying. To estimate the relative states of two satellites, the Kalman Filter algorithms (EKF, UKF) are adopted with the relative range and range rate between two satellites and attitude of a satellite as measurement variables. In case that the initial state and measurements errors are moderate, both...

In this article, an interactive tool for simulation of satellites dynamics and autonomous spacecraft guidance is presented. Different geopotential models orbit propagation Earth-orbiting are provided, which consider earth's gravitational field with various accuracies. The presented software a 3-D visualization platform space analytical capabilities through modules. Taking advantage graphical us...

Three different potential predictors of forecast error – ensemble spread, mean errors of recent forecasts and the local gradient of the predicted field – were compared. The comparison was performed using the forecasts of 500 hPa geopotential and 2-m temperature of the ECMWF ensemble prediction system at lead times of 96, 168 and 240 h, over North America for each day in 2004. Ensemble spread wa...

A probabilistic clustering technique is developed for classification of wintertime extratropical cyclone (ETC) tracks over the North Atlantic. We use a regression mixture model to describe the longitude-time and latitude–time propagation of the ETCs. A simple tracking algorithm is applied to 6-hourly mean sea-level pressure fields to obtain the tracks from either a general circulation model (GC...

We performed an experimental study of large-scale wakes in a rotating shallow-water layer. Standard particle image velocimetry was used to measure the horizontal velocity field, while a laser-induced fluorescence technique was used to measure the geopotential deviation i.e., the interface deviation . According to these measurements, we were able to quantify the dynamics in a wide region of para...