###### Abstract
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Satellite** & **PRN** & **SVN** & **Type** & **Manufacture** & **Launch Date** \\ \hline BDS3-M01 & C19 & C201 & MEO & CAST & 5 November 2017 \\ BDS3-M02 & C20 & C202 & MEO & CAST & 5 November 2017 \\ BDS3-M03 & C27 & C203 & MEO & SECM & 1 January 2018 \\ BDS3-M04 & C28 & C204 & MEO & SECM & 11 January 2018 \\ BDS3-M05 & C22 & C205 & MEO & CAST & 12 February 2018 \\ BDS3-M06 & C21 & C206 & MEO & CAST & 12 February 2018 \\ BDS3-M07 & C29 & C207 & MEO & SECM & 29 March 2018 \\ BDS3-M08 & C30 & C208 & MEO & SECM & 29 March 2018 \\ BDS3-M09 & C23 & C209 & MEO & CAST & 29 July 2018 \\ BDS3-M10 & C24 & C210 & MEO & CAST & 29 July 2018 \\ BDS3-M11 & C26 & C211 & MEO & SECM & 24 August 2018 \\ BDS3-M12 & C25 & C212 & MEO & SECM & 24 August 2018 \\ BDS3-M13 & C32 & C213 & MEO & CAST & 19 September 2018 \\ BDS3-M14 & C33 & C214 & MEO & CAST & 19 September 2018 \\ BDS3-M15 & C34 & C215 & MEO & SECM & 15 October 2018 \\ BDS3-M16 & C35 & C216 & MEO & SECM & 15 October 2018 \\ BDS3-M17 & C36 & C218 & MEO & CAST & 18 November 2018 \\ BDS3-M18 & C37 & C219 & MEO & CAST & 18 November 2018 \\ BDS3-M19 & C41 & C227 & MEO & CAST & 16 December 2019 \\ BDS3-M20 & C42 & C228 & MEO & CAST & 16 December 2019 \\ BDS3-M21 & C43 & C226 & MEO & SECM & 23 November 2019 \\ BDS3-M22 & C44 & C225 & MEO & SECM & 23 November 2019 \\ BDS3-M23 & C45 & C222 & MEO & CAST & 22 September 2019 \\ BDS3-M24 & C46 & C223 & MEO & CAST & 22 September 2019 \\ BDS3-M101 & C38 & C220 & IGSO & CAST & 20 April 2019 \\ BDS3-I02 & C39 & C221 & IGSO & CAST & 24 June 2019 \\ BDS3-I03 & C40 & C224 & IGSO & CAST & 4 November 2019 \\ BDS3-G01 & C59 & C217 & GEO & CAST & 1 November 2018 \\ BDS3-G02 & C60 & C229 & GEO & CAST & 9 March 2020 \\ BDS3-G03 & C61 & C230 & GEO & CAST & 2 June 2020 \\ \hline \hline \end{tabular} \({}^{\text{CAST:}}\) China Academy of Space Technology: SECM: Shanghai Engineering Center for Microsatellites, Chinese Academy of Sciences.  
\end{table} 
Table 1: Operational status of the BDS-3 constellation as of October 2022. Due to the limited amount of tracking stations supporting the BDS-3 new B1C, B2a and B2b signals, and consideration for the compatibility with BDS-2, current BDS-3 POD research work and orbit products are restricted to the old B1I/B3I combination. There is little research on POD of the BDS-3 constellation based on different dual-frequency measurement combinations, especially B2b signal [25; 26; 27; 28], and there is still limited research on observation quality analysis of BDS-3 new signals, especially the B2b signal [29; 30; 31]. We need to investigate the observation quality of BDS-3 operational signals, i.e., B1C, B2a, B2b, B1I and B3I. We should also analyze the BDS-3 satellite POD performance based on new B1C, B2a and B2b combinations by comparing with the old B1 IBS3I combination. In this contribution, POD of BDS-3 satellites based on several dual-frequency measurement combinations are presented. The algorithm for observation quality analysis with C/N0, pseudo-range noise and pseudo-range MP, the MGEX tracking stations used to estimate the BDS-3 orbits and the POD procedure are shown in Section 2. Meanwhile, orbits are validated by the orbit-only SISRE computed between B1 CB2a combination, B1 CB2b combination, B1 IB3I combination, CODE and GFZ final orbits. Moreover, SLR validation is conducted. The corresponding results are shown and investigated in Section 3. Finally, some key aspects are further discussed and a conclusion is formed in the last Section.