Testing General Relativity with LAGEOS, LAGEOS II and Ajisai laser-ranged satellites

The accuracy reached in the past few years by Satellite Laser Ranging (SLR) allows for measuring even tiny features of the Earth's gravitational field predicted by Einstein's General Relativity by means of artificial satellites. The gravitomagnetic dragging of the orbit of a test body is currently under measurement by analyzing a suitable combination of the orbital re siduals of LAGEOS and LAGEOS ‡U. The lower bound of the error in this experiment amount to 12.92%. It is due to the mismodeling in the even zonal harmonics of the geopotential which are the most important sources of systematic error. A similar approach could be used in order to measure the relativistic gravitoelectric pericenter shift in the field of the Earth with a lower bound of the systematic relative error of 6.59~10-3 due to the even zonal harmonics as well. The inclusion of the ranging data to the Japanese passive geodetic satellite Ajisai would im prove such limits to 10.78% and 8.1~10-4 respectively and would allow to improve the accu racy in the determination of the PPN parameters ƒA and ƒA.