Highly-reduced dynamic orbits and their use for global gravity field recovery: A simulation study for GOCE

The so-called highly reduced-dynamic (HRD) orbit determination strategy and its use for the determination of the Earth's gravitational field are analyzed. We discuss the functional model for the generation of HRD orbits, which are a compromise of the two extreme cases of dynamic and purely geometrically determined kinematic orbits. For gravity field recovery the energy integral approach is applied, which is based on the law of energy conservation in a closed system. The potential of HRD orbits for gravity field determination is studied in the frame of a simulated test environment based on a realistic GOCE orbit configuration. The results are analyzed, assessed, and compared with the respective reference solutions based on a kinematic orbit scenario. The main advantage of HRD orbits is the fact that they contain orbit velocity information, thus avoiding numerical differentiation on the orbit positions. The error characteristics are usually much smoother, and the computation of gravity field solutions is more efficient, because less densely sampled orbit information is sufficient. On the other hand, the main drawback of HRD orbits is that they contain external gravity field information, and thus yield the danger to obtain gravity field results which are biased towards this prior informatio

Constraints from orbital motions around the Earth of the environmental fifth-force hypothesis for the OPERA superluminal neutrino phenomenology

It has been recently suggested by Dvali and Vikman that the superluminal neutrino phenomenology of the OPERA experiment may be due to an environmental feature of the Earth, naturally yielding a long-range fifth force of gravitational origin whose coupling with the neutrino is set by the scale M_*, in units of reduced Planck mass. Its characteristic length lambda should not be smaller than one Earth's radius R_e, while its upper bound is expected to be slightly smaller than the Earth-Moon distance (60 R_e). We analytically work out some orbital effects of a Yukawa-type fifth force for a test particle moving in the modified field of a central body. Our results are quite general since they are not restricted to any particular size of lambda; moreover, they are valid for an arbitrary orbital configuration of the particle, i.e. for any value of its eccentricity $e$. We find that the dimensionless strength coupling parameter alpha is constrained to |alpha| <= 1 10^-10-4 10^-9 for 1 R_e <= lambda <= 10 R_e by the laser data of the Earth's artificial satellite LAGEOS II, corresponding to M_* >= 4 10^9 -1.6 10^10. The Moon perigee allows to obtain |alpha| <= 3 10^-11 for the Earth-Moon pair in the range 15 R_e <= lambda = 3 10^10 - 4.5 10^10. Our results are neither necessarily limited to the superluminal OPERA scenario nor to the Dvali-Vikman model, in which it is M_* = 10^-6 at lambda = 1 R_e, in contrast with our bounds: they generally extend to any theoretical scenario implying a fifth-force of Yukawa-type.Comment: LaTex2e, 18 pages, 4 figures, 1 table, 81 reference