| Abstrakt: |
Abstract: Exactly in November 2006 (GPS week 1400), the IGS analysis centers switched from using relative to absolute corrections. At the same time, also the EUREF analysis centers made this switch. Many research groups have evaluated the influence of the usage of relative PCC with respect to absolute PCC on the EPN site coordinates. The authors demonstrated the significant influences of the conversion from relative to absolute PCC. Maximum changes in height of about 30 mm occurred at some sites. The impact of switching from the type-mean to individual calibration model was also analyzed but so far in GPS-only mode. In the paper, the authors compared station positions estimated using GLONASS-only observations when type-mean and individual calibration models were applied. The impact of switching between these models was investigated using one year of observations collected at eight selected ASG-EUPOS station. Post-processing was done using PPP technique in daily observation mode and in pseudo-kinematic mode (15 minutes session). The authors demonstrated that the position offsets in daily observation resulting from the use of individual calibrations instead of type mean igs08.atx calibrations could reach up to 0.5 cm in the up component, while in the horizontal, the offsets generally stayed below 0.1 cm. In pseudokinematic mode the authors obtained up to 1.0 cm in the up component and 0.5 cm in the horizontal components respectively. It is also demonstrated that the differences in the calibrations models propagate directly into the position domain, affecting daily and sub-daily results and giving visible variations and systematic jumps. To detect the periodicity in our results spectral analysis was used. The Lomb- Scargle spectrum calculated for the data revealed that there are strong periodic signals in pseudokinematic results and there is also some periodicity in daily results. |
