## 2 Methodology and Data
In this way, the station coordinates, clock correction of the receiver for each system, wet component of the tropospheric delay, and real ambiguity values were estimated. A list of the used products, models, and methods are shown in Tables 2 and 3. \begin{table}
\begin{tabular}{c c} \hline \hline
**Solution Name** & **Products** \\ \hline BRDM & broadcast products BRD400 DLR; GPS LNAV and Galileo INAV \\  & broadcast products BCEP00 BKG0 with HAS corrections \\ HAS & SSRA00 EUH0; GPS LNAV and Galileo INAV; collected in \\  & real-time with BNC software ([[https://igs.bkg.bund.de/ntrip/bnc](https://igs.bkg.bund.de/ntrip/bnc)]([https://igs.bkg.bund.de/ntrip/bnc](https://igs.bkg.bund.de/ntrip/bnc)) \\  & (accessed on 14 June 2025)) \\  & broadcast products with IGS RTS CNES corrections converted to \\ CNES & daily CNES archive products as SP3, CLK, and BIA \\  & ([[http://www.ppp-wizard.net/products/REAL_TIME/](http://www.ppp-wizard.net/products/REAL_TIME/)]([http://www.ppp-wizard.net/products/REAL_TIME/](http://www.ppp-wizard.net/products/REAL_TIME/)) \\  & (accessed on 14 June 2025) \\ CODE & precise CODE MGEX FINAL products: SP3 with 5 min interval, \\  & CLK with 30 s interval \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Solutions names and input data sources. \begin{table}
\begin{tabular}{c c} \hline \hline
**Items** & **Models/Methods** \\ \hline Positioning mode & static mode \\  & conventional PPP model using undifferenced \\ PPP model & dual-frequency code and phase ionosphere-free linear \\  & combination \\ Sessions & eight three-hour sessions per day (48 sessions for each \\  & station from six days) \\  & BRDM, CNES, and CODE solutions: L1/L2 for GPS and \\  & E1/E5a for Galileo \\  & HAS solution: L1/L2 for GPS and E1/E5b for Galileo \\  & \(\sin^{2}ele\) \\  & Constellation & GPS (G), Galileo (E), GPS+Galileo (GE) \\ Standard deviation of raw observations & code = 0.300 m, phase = 0.002 m \\  & Cut-off elevation angle & 10\({}^{\circ}\) \\  & Interval estimation & 1-s \\  & Periods & six days: from 223 DoY to 228 DoY of 2024 \\  & Reference frame & IGS20 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Methods and models used. I think the table should be on one page. Four different solutions were computed for GPS, Galileo, and GPS+Galileo constellations:  
* **'BRDM' solution**: computed using only broadcast products, with the BRD400 DLR broadcast ephemerides downloaded;
* **'HAS' solution**: computed using broadcast ephemerides combined with HAS corrections. The products were collected in real-time using BNC software;
* **'CNES' solution**: computed using CNES archive products. The broadcast ephemerides and real-time CNES corrections were converted to SP3 and CLK files;
* **'CODE' solution**: computed using the final CODE MGEX products. These products were downloaded as SP3 and CLK with 5 min and 30 s intervals, respectively. The analysis was conducted using a 10\({}^{\circ}\) elevation angle cut-off, with the \(\sin^{2}\mathit{ele}\), function applied for stochastic modeling. The reference coordinates were based on the daily IGS20 SINEX reference frame. The estimated tropospheric delay was compared with the official IGS value. To estimate the ZTD for the BRDM, HAS, and CNES solutions, the GPT3 model was applied, while the VMF3 model was used for the CODE solution [56]. Additionally, for the CODE solution, the CODE MGEX satellite biases were included as observable-specific signal bias (OSB) files [14]. For the HAS and CNES solutions, bias corrections were obtained from the respective correction streams. In the case of the CNES solution, phase bias corrections were also applied, while for the HAS solution, only code bias corrections were used. For the BRDM solution, the Time Group Delay (TGD) data, as transmitted in the navigation messages, were utilized [57].