## 3 Analysis of the LEO Satellite Downlinks in Interference Situations  
Figure 4a shows the satellite trajectories obtained from the TLE data. The blue, red, and green solid lines with circle markers represent the trajectories of the LEO satellite for 13 March (Trajectory 1), 16 March (Trajectory 2), and 21 March (Trajectory 3), 2023, respectively. The ground station is located at latitude 36.33\({}^{\circ}\) and longitude 127.26\({}^{\circ}\). The time at which communication between this ground station and the LEO satellite begins is defined as \(t_{1}\), and the time when communication ends is defined as \(t_{n}\). In general, the data communication time is less than 600 s, so \(t_{1}\) and \(t_{n}\) are defined as 0 and 600 s, respectively, in this scenario. Figure 4b shows the slant distance \(d_{s}\) and elevation angle \(\theta_{s}\) between the ground station and the LEO satellite for each trajectory. The maximum elevation angles of Trajectory 1, Trajectory 2, and Trajectory 3 are 86.8\({}^{\circ}\), 62.7\({}^{\circ}\), and 37.3\({}^{\circ}\), respectively, and the slant distances from the ground station to the satellite at the maximum elevation angle of each trajectory are 550.9 km, 618.6 km, and 908.1 km, respectively. \begin{table}
\begin{tabular}{c c c} \hline  & **Parameters** & **Values** \\ \hline  & **Frequency** & **8 GHz** \\ \cline{2-3} Ground & Bore-sight gain \(G_{r}^{g}\) (\(\xi=0^{\circ}\)) & 59 dBi \\ station & Sidelobe gain \(G_{r}^{g}\) (\(\xi=\psi^{\circ}\)) & \(a_{1}\cdot e^{h_{1}\cdot\xi}+a_{2}\cdot e^{h_{2}\cdot\xi}\) \\ \hline  & Satellite altitude & 550 km \\ LEO & Transmission power \(P_{t}^{s}\) & 30 dBm \\ satellite & Bore-sight gain \(G_{t}^{s}\) & 4.4 dBi \\  & Free-space path loss & \(L_{s}\) \\ \hline  & Transmission power \(P_{t}^{i}\) & 70 dBm \\ Airborne & Bore-sight gain \(G_{t}^{i}\) & 30 dBi \\ interference & Velocity & 850 km/h \\ source & Interference source altitude \(h_{i}\) & 3 km, 6 km, 9 km, and 12 km \\  & Free-space path loss & \(L_{i}\) \\ \hline \end{tabular}
\end{table} 
Table 1: Parameters for the downlink simulation. Figure 4: _Cont_. Figure 5a,b show the airborne interference source paths during the data communication period on 13 March 2023. \(d_{\text{p}}\) is the distance between the ground station and the interference source, and the minimum \(d_{\text{p}}\) for paths 1, 2, and 3 is 100 km, 200 km, and 300 km, respectively, with the paths parallel to the LEO satellite using Trajectory 1. The ground paths of the interference source and satellite, and the ground station location, are illustrated on a map (Mercator projection) based on the WGS84 geodetic data. To observe the movement of the interference source from the perspective of the ground station, its elevation angle \(\theta_{i}\) and slant distance \(d_{\text{i}}\) are derived using ENU coordinates, with the ground station as the origin location. When the altitude of the interference source is fixed at 12 km, the maximum elevation angles are 6.7\({}^{\circ}\) (Path 1), 3.4\({}^{\circ}\) (Path 2), and 2.2\({}^{\circ}\) (Path 3). The minimum slant distances are 101.6 km (Path 1), 201.7 km (Path 2), and 301.9 km (Path 3). Figure 4: Location information for LEO satellite trajectories during the data communication period: (**a**) trajectories on a map based on the WGS84 geodetic data; (**b**) elevation angle \(\theta_{\text{s}}\) and slant distance \(d_{\text{s}}\) for each trajectory using the ENU coordinate system. Figure 5: _Cont._  
Figure 6 shows the relative angle difference \(\psi\) and \(J/S\) ratio results obtained by varying the altitude of the airborne interference when the LEO satellite moves along Trajectory 1.