# Assessment of GNSS Galileo Contribution to the Modernization of CROPOS's Services
## 3 Results  
### Static Observations and Processing in Trimble Business Center  
During the survey, the GNSS receiver (antenna) was oriented towards the north to mitigate the variation in the antenna phase centers. For the GNSS receiver Trimble R12, the North Reference Point (NRP) is the Man-Machine Interface (MMI). The antenna calibration values assume that the NRP is properly oriented to true north [64]. The baseline processing was carried out in Trimble Business Center (TBC) ver. 5.3. TBC is a program package with a GPS processing engine introduced in 2005. Over time, a GNSS processing engine has evolved, and since ver. 3.5 (released in 2015), it supports the independent GNSS constellation solutions including BeiDou-only, GLONASS-only, and BeiDou + GLONASS-only combinations. Starting with the TBC, ver. 3.90, Galileo-only post-processing baseline solution was enabled, as well [48]. In version 4.0 (released in 2017), a modernized approach for static GNSS baseline processing was introduced: multiple processing modes are dynamically chosen according to the baseline length and duration of observation sessions [65]. Moreover, from ver. 4.00 on, the new engine also supports \begin{table}
\begin{tabular}{c c c c} \hline
**Session** & **Series** & **Start Time (CET)** & **PDOP** & **Number of SV** \\ \hline \multirow{8}{*}{6. (A-6)} & VPPS (GGG) & 12:54:27 & 1.3 & 18 \\ \cline{2-4}  & VPPS (GGG) & 12:55:09 & 1.3 & 18 \\ \cline{2-4}  & VPPS (GGG) & 12:55:43 & 1.3 & 18 \\ \cline{2-4}  & VPPS (GAL-only) & 12:59:33 & 2.7 & 7 \\ \cline{2-4}  & VPPS (GAL-only) & 13:00:07 & 2.7 & 7 \\ \cline{2-4}  & VPPS (GAL-only) & 13:00:43 & 2.7 & 7 \\ \cline{2-4}  & STATIC (GGG) & 13:02–13:20 & & \\ \hline \multirow{8}{*}{7. (A-7)} & VPPS (GGG) & 13:56:45 & 1.3 & 23 \\ \cline{2-4}  & VPPS (GGG) & 13:57:25 & 1.3 & 23 \\ \cline{2-4}  & VPPS (GGG) & 13:58:01 & 1.3 & 23 \\ \cline{2-4}  & VPPS (GAL-only) & 13:59:39 & 2.4 & 6 \\ \cline{2-4}  & VPPS (GAL-only) & 14:00:12 & 2.4 & 6 \\ \cline{2-4}  & VPPS (GAL-only) & 14:00:54 & 2.4 & 6 \\ \cline{2-4}  & STATIC (GGG) & 13:30–13:52 & & \\ \hline \multirow{8}{*}{8. (A-8)} & VPPS (GGG) & 14:26:50 & 1.6 & 23 \\ \cline{2-4}  & VPPS (GGG) & 14:27:30 & 1.3 & 23 \\ \cline{2-4}  & VPPS (GGG) & 14:28:06 & 1.3 & 23 \\ \cline{2-4}  & VPPS (GAL-only) & 14:30:22 & 3.0 & 6 \\ \cline{2-4}  & VPPS (GAL-only) & 14:30:56 & 3.0 & 6 \\ \cline{2-4}  & VPPS (GAL-only) & 14:31:33 & 3.0 & 6 \\ \cline{2-4}  & STATIC (GGG) & 14:32–14:55 & & \\ \hline \multirow{8}{*}{9. (A-9)} & VPPS (GGG) & 16:13:59 & 1.1 & 25 \\ \cline{2-4}  & VPPS (GGG) & 16:14:32 & 1.0 & 26 \\ \cline{2-4}  & VPPS (GGG) & 16:15:08 & 1.0 & 26 \\ \cline{2-4}  & VPPS (GAL-only) & 16:17:08 & 1.6 & 7 \\ \cline{2-4}  & VPPS (GAL-only) & 16:17:43 & 2.1 & 6 \\ \cline{2-4}  & VPPS (GAL-only) & — & — & — \\ \cline{2-4}  & STATIC (GGG) & 16:31–16:53 & & \\ \hline \end{tabular}
\end{table} 
Table 2: _Cont._three frequency post-processing, mixed-signal post-processing, and provides support for the Galileo E5A, E5B, and E5 AltBOC signals, improving the accuracy and reliability of the processed baseline solution [66]. The baseline processing and the subsequent network adjustment were carried out within several individual projects. After the import of CORS, ZAGR, and VRS observation data in T02 format, the observation data collected with the Trimble R12 receiver were imported in T04 format. Both VRS stations along with the CORS ZAGR station were selected (defined) so as to form an approximate equilateral triangle, with station A being approximately in the center of said triangle. In each project, the following settings were applied: coordinate system HTRS96/TM (the official coordinate system of Croatia), GRS80 ellipsoid, and Transverse Mercator (TM) projection with the central meridian 16\({}^{\circ}\)30\({}^{\prime}\) and scale factor 0.9999. For baselines processing, the following parameters were set: elevation mask 10\({}^{\circ}\), broadcast ephemeris used, and confidence level display 95%.