Conservative evaluation of the uncertainty in the LAGEOSLAGEOS II LenseThirring test
Abstract
We deal with the test of the general relativistic gravitomagnetic LenseThirring effect currently being conducted in the Earth’s gravitational field with the combined nodes Ω of the laserranged geodetic satellites LAGEOS and LAGEOS II. One of the most important sources of systematic uncertainty on the orbits of the LAGEOS satellites, with respect to the LenseThirring signature, is the bias due to the even zonal harmonic coefficients J _{ℓ} of the multipolar expansion of the Earth’s geopotential which account for the departures from sphericity of the terrestrial gravitational potential induced by the centrifugal effects of its diurnal rotation. The issue addressed here is: are the so far published evaluations of such a systematic error reliable and realistic? The answer is negative. Indeed, if the difference ∆ J _{ℓ} among the even zonals estimated in different global solutions (EIGENGRACE02S, EIGENCG03C, GGM02S, GGM03S, ITGGrace02, ITGGrace03s, JEM01RL03B, EGM2008, AIUBGRACE01S) is assumed for the uncertainties δ J _{ℓ} instead of using their moreorless calibrated covariances σ _{J_ell } , it turns out that the systematic error δμ in the LenseThirring measurement is about 3 to 4 times larger than in the evaluations so far published based on the use of the covariances of one model at a time separately, amounting up to 37% for the pair EIGENGRACE02S/ITGGrace03s. The comparison among the other recent GRACEbased models yields bias as large as about 2530%. The major discrepancies still occur for J _{4}; J _{6} and J _{8}, which are just to which the zonals the combined LAGEOS/LAGOES II nodes are most sensitive.
 Publication:

Central European Journal of Physics
 Pub Date:
 February 2010
 DOI:
 10.2478/s1153400900606
 arXiv:
 arXiv:0710.1022
 Bibcode:
 2010CEJPh...8...25I
 Keywords:

 General Relativity and Quantum Cosmology;
 Astrophysics;
 Physics  Geophysics;
 Physics  Space Physics
 EPrint:
 LaTex, 12 pages, 12 tables, no figures, 64 references. To appear in Central European Journal of Physics (CEJP)