Since all Earth observing systems must refer to one and the same reference frame, the establishment of an improved reference frame is an important prerequisite for precise orbit and gravity field determination, and Earth studies in general. Based on improved models we have at AUIB started to process data from more than 250 globally distributed stations belonging to the network of the International GNSS Service (IGS). The time span of the processing is covering the period from 1994 to recent years. Additionally, to ensure high quality products for the purposes of EGSIEM, the orbital products are validated using Satellite Laser Ranging (SLR) observations.
Preliminary results of our processing effort were presented at the International Union of Geodesy and Geophysics General Assembly 2015 (IUGG), see (http://www.bernese.unibe.ch/publist/2015/post/IUGG_Maier_et_al.pdf ). We have quantified the impact of the extended version of the original Empirical CODE Orbit Model on the computed GNSS orbits. The main motivation for the development and use of the new ECOM were shortcomings in the original modeling of solar radiation pressure. This deficiency is especially apparent for GLONASS satellites due to their elongated shape. Systematic errors could be successfully removed by applying the extended version of the ECOM model.
