## 5 Conclusions  
In this paper, the interference between 5G and BeiDou RDSS is analyzed from two perspectives: signal and system. The key conclusions are as follows.  
In this paper, a compatibility assessment is first carried out from the perspective of the signal. The effects of interference on BeiDou capture and tracking performance are illustrated, and the effects of equivalent carrier-to-noise ratio on carrier tracking performance and code tracking performance under the influence of interference are analyzed. Finally, the safe coexistence distance of the two systems from the signal perspective is obtained from the perspective of capture probability.  
Based on the link budget criterion, the ACLR model is introduced, and the interference of 5G base stations and 5G terminals to RDSS receivers under different frequency isolation, as well as the required distance isolation for safe coexistence, are analyzed. Combined with the subsequent research scenarios, the interference of 5G terminals can be ignored, and the worst-case scenario shows that the 5G base stations have an impact on the RDSS receivers in the range of 4.2 km.  
Finally, the real flight data are combined with the simulation model to obtain the aggregate interference from ground 5G base stations during the takeoff and landing of an airplane on different routes and in different 5G propagation environments. The simulation results show that when the airplane is closer to the ground, the ground 5G base stations will cause harmful interference to the RDSS receiver. Attention should be focused on the process of the aircraft taxiing, accelerating, lifting up, and leaving the ground, as well as the process of the aircraft descending from the air, approaching the landing area, decelerating, grounding, and taxiing to a stop during the landing phase, and certain physical isolation measures should be taken to avoid affecting the normal operation of the RDSS receiver in a timely manner.  
Conceptualization, W.C. and S.S.; data curation, R.L. and Y.T.; formal analysis, S.S.; funding acquisition, R.L.; investigation, W.C. and Y.T.; methodology, W.C.; software Y.T.; writing--original draft, R.L. and Y.T.; writing--review and editing, W.C., Y.T., S.S. and R.L. All authors have read and agreed to the published version of the manuscript.  
This work was supported in part by the National Natural Science Foundation of China Civil Aviation Joint Fund Key Project under Grant U2233215, and in part by the Open Fund of Key Laboratory of Civil Aircraft Airworthiness Technology under Grant SH2022070502.  
Data Availability StatementData are contained within the article.  
The authors declare no conflicts of interest.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Dissemination Environment** & **Flight Altitude (m)** & **Horizontal Distance (m)** & **Aggregate Interference (dBm)** \\ \hline \multirow{3}{*}{EDDB-KIAD Free Space} & 113.4 & 1394 & \(-\)143.60 \\  & 73.7 & 658 & \(-\)137.11 \\  & 41.9 & 60.5 & \(-\)118.03 \\ \hline \multirow{3}{*}{KJFK-KLAX Free Space} & 115.3 & 747 & \(-\)138.26 \\  & 95.6 & 365 & \(-\)132.24 \\  & 76 & 25 & \(-\)118.26 \\ \hline \multirow{3}{*}{EDDB-KIAD RMA} & 113.4 & 1394 & \(-\)183.53 \\  & 73.7 & 658 & \(-\)167.91 \\  & 41.9 & 60.5 & \(-\)122.23 \\ \hline \multirow{3}{*}{KJFK-KLAX RMA} & 115.3 & 747 & \(-\)170.72 \\  & 95.6 & 365 & \(-\)156.29 \\ \cline{1-1}  & 76 & 25 & \(-\)122.79 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Summary analysis of interference data from EDDB-KIAD and KJFK-KLAX during the landing phase.