2.2. Space geodetic data analysis with c5++
The software package 'c5++' [13] has been developed with the purpose of supporting the combination of space geodetic data from VLBI, GPS and SLR on the observation level and also to allow processing of single-technique solutions. Since c5++ uses consistent geodetic/geophysical models [14] for all space geodetic techniques and all analysis steps, it is guaranteed that differences of the estimated parameters that are derived from e.g. VLBI and GPS do not originate from different models or inconsistent corrections, but are directly related to the performance of each technique. Moreover, the possibility to combine data on the observation level allows to study the impact of combining techniques, with the purpose to improve the target parameters. The concept of combination on the observation level has been successfully demonstrated in [15] and will be applied here (see section 3.3).