Effects of Earth tesseral and sectorial tides on the determination of the Lense-Thirring effect

The general relativistic Lense-Thirring effect can be detected by means of a suitable combination of orbital residuals of the laser-ranged LAGEOS and LAGEOS II satellites. While this observable is not affected by the orbital perturbation induced by the zonal Earth solid and ocean tides, it is sensible to those generated by the tesseral and sectorial tides. The assessment of their influence on the measurement of the parameter μLT , with which the gravitomagnetic effect is accounted for, is the goal of this paper. After simulating the combined residual curve by calculating accurately the mismodeling of the more effective tidal perturbations, it has been found that, while the solid tides affect the recovery of μLT at a level always well below 1%, for the ocean tides and the other long-period signals ∆μ depends strongly on the observational period and the noise level: ∆μtides ≃ 2% after 7 years. The aliasing effect of K1 l = 3 p = 1 tide and SRP(4241) solar radiation pressure harmonic, with periods longer than 4 years, on the perigee of LAGEOS II yield to a maximum systematic uncertainty on μLT of less than 4% over different observational periods. The zonal 18.6-year tide does not affect the combined residuals.