## 3 Results
### Consistency of Precise Products from Different Analysis Centers
#### 3.3.4 BDS
Different from BDS-2 GEO satellites, the inconsistency results between the real-time and post-processed precise products are comparable to those only involving the post-processed products in terms of the radial orbit, clock and SISRE statistics, but the along-track and cross-track orbit differences of the former ones are still larger than those of the later ones by several centimeters. The differences of radial orbits, along-track orbits, cross-track orbits, clocks and SISREs among different ACs for BDS-2 IGSO satellites vary within a range of 9.3-13.4 cm, 7.1-15.5 cm, 7.3-14.6 cm, 0.18-0.40 ns and 6.8-10.1 cm, respectively. Table 6 illustrates the corresponding statistical results for BDS-2 MEO and BDS-3 MEO satellites. It should be noted that the precise products were absent for BDS-3 GEO and IGSO satellites during the analysis period. The consistency of precise satellite products among different ACs for the BDS-2 and BDS-3 MEO satellites is further improved in comparison to the BDS-2 GEO and IGSO satellites. The precise products of BDS-3 MEO satellites achieve a slightly worse consistency results among different ACs than the BDS-2 MEO satellites. For both BDS-2 and BDS-3 MEO satellites, the WHU and GFZ precise satellite products have the best consistency, followed by that between ESA and GFZ precise products. Except for the radial orbit differences of BDS-2 MEO satellites, the inconsistency between real-time and post-processed products is larger than that among post-processed products. As to the three orbital components, the inconsistency among the post-processed products with a varying range of 2.2-5.6 and 2.6-6.5 cm for the BDS-2 and BDS-3 MEO satellites seems to be \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Items**} & \multirow{2}{*}{**ACs**} & \multicolumn{3}{c}{**ACs (for BDS-2 GEO)**} & \multicolumn{3}{c}{**ACs (for BDS-2 IGSO)**} \\ \cline{3-8}  & & **GFZ** & **WHU** & **CNES** & **GFZ** & **WHU** & **CNES** \\ \hline \multirow{3}{*}{Radial (cm)} & ESA & – & – & – & 9.9 & 13.4 & 11.0 \\  & GFZ & – & 15.2 & 49.6 & – & 10.0 & 9.3 \\  & WHU & – & – & 48.3 & – & – & 13.3 \\ \hline \multirow{3}{*}{Along-Track (cm)} & ESA & – & – & – & 9.0 & 10.2 & 14.5 \\  & GFZ & – & 193.8 & 324.1 & – & 7.1 & 14.5 \\  & WHU & – & – & 355.3 & – & – & 15.5 \\ \hline \multirow{3}{*}{Cross-Track (cm)} & ESA & – & – & – & 9.2 & 11.2 & 14.3 \\  & GFZ & – & 109.0 & 132.1 & – & 7.3 & 13.4 \\  & WHU & – & – & 125.7 & – & – & 14.6 \\ \hline \multirow{3}{*}{Clock (rs)} & ESA & – & – & – & 0.18 & 0.34 & 0.28 \\  & GFZ & – & 0.39 & 0.72 & – & 0.31 & 0.28 \\  & WHU & – & – & 0.70 & – & – & 0.40 \\ \hline \multirow{3}{*}{SISRE (cm)} & ESA & – & – & – & 8.7 & 10.1 & 9.2 \\  & GFZ & – & 22.1 & 54.4 & – & 7.3 & 6.8 \\ \cline{1-1}  & WHU & – & – & 55.2 & – & – & 8.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: RMSs of epoch-wise differences of precise satellite orbit and clock corrections among different ACs as well as SISRE statistics for BDS-2 GEO and IGSO satellites. at a similar level, while the corresponding fluctuation range of the RMS difference between the real-time and post-processed products increases to 3.4-3.9, 9.8-10.9 and 7.1-8.2 cm, and 5.0-6.5, 15.3-16.4 and 10.4-11.2 cm for the radial, along-track and cross-track orbital components for the BDS-2 and BDS-3 MEO satellites, respectively. The clock differences of BDS-2 and BDS-3 MEO satellites among the post-processed products are comparable to those of GPS satellites, which range from 0.05 to 0.08 ns for BDS-2 MEO satellites, and from 0.11 to 0.14 ns for BDS-3 MEO satellites, respectively. The RMS values of clock differences between the post-processed and real-time products are enlarged by a factor of two to three times, in comparison to those among the post-processed products. The SISRE difference among the post-processed products of the BDS-2 MEO satellites is comparable to that of BDS-3 MEO satellites, and ranges from 2.6-4.1 and 3.2-3.7 cm for the two satellite constellations, respectively.