Satellite Laser Ranging technique as a tool for the determination of the Schwarzschild, de Sitter and Lense-Thirring effects

Satellite Laser Ranging (SLR) is a modern technique used in various research areas and applications related to geodesy and geodynamics. It is commonly used for tasks such as establishing the International Terrestrial Reference Frame (ITRF), monitoring Earth Orientation Parameters (EOP), determining the geocenter, measuring fundamental physical constants, calibrating microwave tracking techniques, conducting time transfer experiments, and studying gravitational and general relativistic effects. Laser measurements of the LARES and LAGEOS satellites are used to determine the relativistic effects acting on these satellites. The objective of the present research is to analyze the perturbing forces of relativistic origin (Schwarzschild, de Sitter and Lense-Thirring effects) acting on the LARES, LAGEOS-1 and LAGEOS-2 satellites. By using data from fifteen SLR measurement stations, the precise orbits of these satellites were determined over a span of 840 hours using the GEODYN II orbital software package. The calculation process used a set of procedures, models of forces, and constants that are currently recommended by the International Earth Rotation and Reference Systems Service (IERS) and the International Laser Ranging Service (ILRS). Based on the precise orbits of the LARES, LAGEOS-1, and LAGEOS-2 satellites, calculations were made to determine the values of relativistic accelerations acting on these satellites. These values oscillate with a period equal to half of the orbital period for the de Sitter and Lense-Thirring effects, and a quarter of the orbital period for the Schwarzschild effect.