On use of Starlette and Stella Laser measurements in determination of Earth Orientation Parameters (EOP) and SLR stations' coordinates

摘要

The present work deals with the calculation of Laser stations coordinates and Earth Orientation Parameters (EOP) based on observations of Low Earth Orbit (LEO) satellites, namely Starlette (STL) and Stella (STA). The orbits of these satellites are less accurate because they are more affected by the gravitational and non-gravitational forces than those of high satellites as LAGEOS-Ⅰ (LA1) and LAGEOS-Ⅱ (LA2). The objective is to achieve good quality on the geodetic products by inter-satellite combination of Low and High satellites data. The orbit computation of the different satellites is performed with GINS software and the laser data processing is carried out by MATLO software, with consideration of a recent GRACE gravity model (Eigen_Grace-03s) in the processing, for a period of fouryears (between January 2002 and December 2005). The time series of the results are projected according to ITRF2000, by CATREF software, where the Helmert transformation parameters are obtained. We compare two series of solutions: LA1+LA2 (LL) only, and a four-satellite combination based on LA1+LA2+STL+STA (LLSS), in terms of quality of the weekly stations positions, EOP and Geocentre variations. The results presented show that the data obtained from LEO satellites such as Starlette and Stella can be successfully used for precise determination of the SLR geodetic products.