## 3 Signal Quality Analysis
### SQA2: Signal Continuity Analysis  
The discontinuity in the carrier tracking loop generates different integer ambiguity values and causes reduction in user navigation continuity. Cycle slips can occur for one or more epochs. Thus, all  
\begin{table}
\begin{tabular}{l l l l l l l l l l} \hline \hline
**Ele.-c** & 10 & 20 & 30 & 40 & 50 & 60 & 70 & 80 & 90 \\ \hline \hline \multicolumn{10}{c}{**GPS**} \\ \hline
**Mean** & 41.3 & 43.2 & 45.3 & 47.5 & 48.7 & 49.4 & 49.9 & 50.1 & 49.9 \\
**Std** & 2.0 & 1.6 & 1.2 & 1.0 & 0.8 & 0.6 & 0.4 & 0.6 & 0.8 \\ \hline \multicolumn{10}{c}{**BDS GEO**} \\ \hline
**Mean** & NaN & 38.7 & NaN & 42.9 & NaN & 47.0 & 47.0 & NaN & NaN \\
**Std** & NaN & 0.8 & NaN & 1.5 & NaN & 0.3 & 0.2 & NaN & NaN \\ \hline \multicolumn{10}{c}{**BDS IGSO**} \\ \hline
**Mean** & 36.6 & 38.2 & 40.2 & 42.8 & 44.2 & 45.4 & 46.6 & 47.3 & 47.6 \\
**Std** & 2.1 & 1.3 & 1.1 & 1.1 & 0.7 & 0.9 & 0.6 & 0.5 & 0.2 \\ \hline \multicolumn{10}{c}{**BDS MEO**} \\ \hline
**Mean** & 40.0 & 41.4 & 43.2 & 45.7 & 47.1 & 47.9 & 48.3 & 48.5 & 48.5 \\
**Std** & 1.4 & 1.6 & 1.3 & 1.2 & 1.0 & 0.8 & 0.6 & 0.8 & 0.3 \\ \hline \hline \end{tabular}
\end{table}
Table 6: SQA1 statistical results.  
Figure 8: BDS GEO elevation angle with respect to C/N\({}_{0}\).  
cycle slips during the experiment period are counted for each satellite. This section uses the number of measurement epochs without cycle slip compared to the total received data as a continuity indicator for each satellite.  
Figure 9 shows the continuity analysis for GPS satellites. The upper figure shows the continuity value for each GPS satellite. The mean value of GPS satellite continuity is 99.9914%. The lower figure shows the total number of cycle slips for each GPS satellite during the experiment period. The green circles indicate that the satellite had no cycle slips during the day (and thus 100% continuity). The red circle indicates that receiver did not receive data from PRN 30. GPS PRN 6 had the most cycle slips and the cycle slip number is 17 epochs during a day.  
Figure 10 shows the continuity analysis for BDS satellites. The total BDS constellation continuity is 99.9785%, which is lower than that for GPS. This is due to several reasons. First, the BDS GEO PRN 5 satellite had the lowest elevation angle and lost lock all the time. The other GEO satellites had better continuity. Thus, the statistical results for BDS GEO PRN 5 are given separately in order to clarify its impact. Second, the BDS IGSO PRN 6 and 10 satellites had poorer continuity than that of the other IGSO satellites. In addition to the BDS GEO PRN 5, the cycle slip number of BDS IGSO is the highest of all BDS satellites. Finally, the BDS MEO PRN 11 satellite lost lock for a while. The remaining BDS MEO satellites had 100% continuity. As a result, the BDS GEO and IGSO satellites had poorer continuity than the BDS MEO satellites. Because the user position is static and the GPS and BDS signals are received in the same environment at the same time, the discontinuity result of BDS satellites may have been caused by the BDS satellites. The statistical results are shown in Table 7.  
Figure 10: BDS continuity and cycle slip number.  
Figure 9: GPS continuity and cycle slip number.