Conservative evaluation of the uncertainty in the LAGEOS-LAGEOS II Lense-Thirring test

Abstract

Abstract:We deal with the test of the general relativistic gravitomagnetic Lense-Thirring effect currently being conducted in the Earth's gravitational field with the combined nodes Ω of the laser-ranged 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 Lense-Thirring signature, is the bias due to the even zonal harmonic coefficients J 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 among the even zonals estimated in different global solutions (EIGEN-GRACE02S, EIGEN-CG03C, GGM02S, GGM03S, ITG-Grace02, ITG-Grace03s, JEM01-RL03B, EGM2008, AIUB-GRACE01S) is assumed for the uncertainties δJ instead of using their more-or-less calibrated covariances σ J , it turns out that the systematic error δµ in the Lense-Thirring 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 EIGEN-GRACE02S/ITGGrace03s. The comparison among the other recent GRACE-based models yields bias as large as about 25−30%. 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. PACS

Phenomenology of the Lense-Thirring effect in the solar system

“…Latest tests have been reported by Ciufolini and Pavlis (2004), Ciufolini et al (2006), Ciufolini (2007), Ciufolini et al (2009), Lucchesi (2007a, and Ries et al (2008); Ries (2009) with only the nodes of both satellites according to a combination of them explicitly proposed by Iorio and Morea (2004). The total uncertainty reached is still a matter of debate (Iorio 2005a;Ciufolini and Pavlis 2005;Lucchesi 2005;Iorio 2006bIorio , 2007dIorio , 2009cIorio , 2010aCiufolini et al 2009) because of the lingering uncertainties in the Earth's multipoles and in how to evaluate their biasing impact; it may be as large as ≈ 20 − 30% according to conservative evaluations (Iorio 2005a(Iorio , 2006b(Iorio , 2007d(Iorio , 2009c(Iorio , 2010a, while more optimistic views Pavlis 2004, 2005;Ciufolini et al 2006;Ries et al 2008;Ries 2009;Ciufolini et al 2009) point towards ≈ 10 − 15%.…”

Clocks around Sgr A*

“…per orbit. The phenomenon of frame dragging has been first observed only in recent years, by using laser ranging to accurately determine the orbit of the Lageos satellites and reveal the relativistic effect of the Earth's spin (Ciufolini & Pavlis 2004;Iorio 2010). The recently launched LARES satellite aims to measure the effect to an accuracy of 1% (Ciufolini et al 2009).…”

Gravitomagnetism and Gravitational Waves

“…Latest tests have been reported by Ciufolini and Pavlis [73,74], Lucchesi [75] and Ries and coworkers [76] with only the nodes of both the satellites according to a combination of them explicitly proposed by Iorio [77]. The total uncertainty reached is still matter of debate [78,79,80,81,82,83,84] because of the lingering uncertainties in the Earth's multipoles and in how to evaluate their biasing impact; it may be as large as ≈ 20−30% according to conservative evaluations [78,81,82,83,84], while more optimistic views [73,74,76] point towards 10 − 15%. Several authors [85,86,87,88,89] explored the possibility of using other currently orbiting SLR geodetic satellites in addition to LAGEOS and LAGEOS II.…”