## 5 Conclusions  
This contribution focused on the analysis and evaluation of BDS-2 and BDS-3 broadcast ephemeris in terms of the accuracy of the orbit and clock offsets, SISRE, orbit-only SISRE and the SPP performances. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline
**Station** & **Receiver** & **North** & **East** & **Up** & **3D** \\ \hline POTS & JAVADTRE3 & -37.718 & -39.976  
We prove that the datum of broadcast clock offsets for BDS-2 and BDS-3 are inconsistent and propose the SISRE processing strategies of calculating SISRE of BDS-2 and BDS-3 separately and the new BDS-2 and BDS-3 combined SPP model. From the viewpoint of the assessment of broadcast clock offsets, selecting one and the same average BMP clock values of satellites of the same constellation can eliminate the datum of the satellite clock offsets, and the average BMP clock values of BDS-2 and BDS-3 are not equal, which can indirectly prove that the datum of broadcast clock offsets for BDS-2 and BDS-3 are inconsistent. To eliminate the datum of the satellite clock offsets and avoid the inconsistency between BDS-2 and BDS-3, the average BMP clock values of BDS-2 and BDS-3 satellites are calculated separately, which can obtain the objective and scientific evaluation results. The mean STD of three ACs for BDS-2 and BDS-3 broadcast clock offsets are 1.22 ns and 0.58 ns, and the improvement rate of BDS-3 mean STD is 52.49% compared to BDS-2. Meanwhile, the mean RMS for BDS-2 and BDS-3 are 2.90 ns and 1.73 ns, respectively, and that of BDS-3 can be improved by 40.34% compared to BDS-2. About the broadcast orbits, the mean RMS and STD of all BDS-2 satellites are (1.46, 3.04, 1.21) m and (0.34, 1.00, 0.99) m, and that of all BDS-3 satellites are (0.20, 0.32, 0.28) m and (0.07, 0.23, 0.23) m for the average of three ACs in radial, along-track and cross-track directions, respectively. The broadcast orbit accuracy of BDS-3 is roughly improved by one order magnitude compared to BDS-2. The RMS and STD of BDS-3 broadcast orbit errors are improved by (86.47%, 89.47%, 76.86%) and (79.41%, 77.00%, 76.78%) compared to BDS-2 in three directions, respectively. Due to the inconsistency of the datum of clock offsets for BDS-2 and BDS-3, BDS-2 and BDS-3 cannot solve SISRE together. We propose the SISRE processing strategies of calculating SISRE of BDS-2 and BDS-3 separately. Without additional bias correction, the proposed SISRE processing strategies can more scientifically and accurately reflect the accuracy of the current broadcast ephemeris of BDS-2 and BDS-3. For BDS-2 signal-in-space accuracy, the mean RMS and STD of three ACs are (1.78 and 0.40) m for SISRE, and (1.72 and 0.34) m for orbit-only SISRE. As for BDS-3, the mean RMS and STD of three ACs are (0.50 and 0.14) m for SISRE, and (0.17 and 0.04) m for orbit-only SISRE, respectively, and the mean RMS and STD of BDS-3 are improved by (71.91% and 65.00%) for SISRE and (90.12% and 88.24%) for orbit-only SISRE compared to BDS-2, respectively. The BDS-3 signal-in-space accuracy has reached 0.50 m, and its accuracy will be further improved with the development of BDS. In BDS-2 and BDS-3 combined SPP, ISB is affected by the inconsistency of the datum of BDS-2 and BDS-3 broadcast clock offsets and receiver pseudorange bias. Under this background, we analyze the ISB characteristics and SPP performance of different types of receivers separately. For JAVAD TRE_3 receivers, the ISB is relatively minor, and setting the parameter to estimate ISB will reduce the stability of the SPP model and degrade the positioning accuracy of the SPP. However, for the TRIMBLE ALLOY, SEPT POLARX5, CETC-54-GMR-4016, CETC-54-GMR-4011 and UB4B0-13478 receivers, estimating ISB can improve the positioning accuracy by 20.15%, 19.81% and 12.76% in three directions, respectively. Finally, we recommend that BDS-2 and BDS-3 should be treated separately when assessing the signal-in-space accuracy of BDS-2 and BDS-3.