## 3 Analysis of the LEO Satellite Downlinks in Interference Situations
\(\Psi_{\rm{ave}}\) values are 70\({}^{\circ}\), 69.7\({}^{\circ}\), 69.3\({}^{\circ}\), and 68.9\({}^{\circ}\), and \(J_{\rm{ave}}/S_{\rm{ave}}\) ratios are \(-\)30.3 dB, \(-\)30.2 dB, \(-\)30.1 dB, and \(-\)30.1 dB, respectively. Figure 8: Relative angle differences \(\psi\) and \(J/S\) ratios of the airborne interference source at different altitudes when the LEO satellite moves along Trajectory 2: (**a**) \(\psi\) for Path 1; (**b**) \(J/S\) ratio for Path 1; (**c**) \(\psi\) for Path 2; (**d**) \(J/S\) ratio for Path 2; (**e**) \(\psi\) for Path 3; (**f**) \(J/S\) ratio for Path 3. Figure 9a is for the case of Trajectory 3 (21 March 2023). The maximum elevations angles for Paths 1, 2, and 3 are \(6.7^{\circ}\), \(3.4^{\circ}\), and \(2.2^{\circ}\), respectively, and the slant distances are \(101.6\) km, \(201.7\) km, and \(301.9\) km, respectively. Figure 10a,b show the \(\psi\) and \(J/S\) ratios when the airborne interference source moves along Path 1. For altitudes of 3 km, 6 km, 9 km, and 12 km of the airborne interference source, the \(\psi_{\rm ave}\) values are \(40.7^{\circ}\), \(39.6^{\circ}\), \(38.5^{\circ}\), and \(37.5^{\circ}\), respectively. The \(J_{\rm ave}/S_{\rm ave}\) ratios are \(-12.2\) dB, \(-11.9\) dB, \(-11.5\) dB, and \(-11.1\) dB, respectively. Figure 10c,d present the \(\psi\) and \(J/S\) ratios for Path 2. The \(\psi_{\rm ave}\) values are \(48.4^{\circ}\), \(47.8^{\circ}\), \(47.3^{\circ}\), and \(46.8^{\circ}\), and the \(J_{\rm ave}/S_{\rm ave}\) ratios are \(-20.1\) dB, \(-19.9\) dB, \(-19.7\) dB, and \(-19.6\) dB, respectively. Figure 10e,f illustrate the \(\psi\) and \(J/S\) ratios when the interference source moves along Path 3. The \(\psi_{\rm ave}\) values are \(51.3^{\circ}\), \(69.7^{\circ}\), \(69.3^{\circ}\), and \(68.9^{\circ}\), with the \(J_{\rm ave}/S_{\rm ave}\) ratios of \(-30.3\) dB, \(-30.2\) dB, \(-30.1\) dB, and \(-30.1\) dB, respectively. Figure 4:0 Airborne interference source paths during the data communication period when the LEO satellite moves along Trajectory 3: (**a**) paths on a map based on the WGS84 geodetic data; (**b**) elevation angle \(\theta_{i}\) and slant distance \(d_{i}\) for each path. In Table 2, \(\psi_{\rm{ave}}\) values and \(J_{\rm{ave}}/S_{\rm{ave}}\) ratios are summarized. As can be seen from these results, for satellite Trajectory 1, the highest \(\psi_{\rm{ave}}\) value (\(83.6^{\circ}\)) is observed when the interference source moves along Path 3 at an altitude of 3 km. In this case, the \(J_{\rm{ave}}/S_{\rm{ave}}\) ratio is also the lowest at \(-33.6\) dB. When the satellite moves along Trajectory 3 with Path 1 (an altitude of 12 km), the lowest \(\psi_{\rm{ave}}\) value (\(37.5^{\circ}\)) and the highest \(J_{\rm{ave}}/S_{\rm{ave}}\) ratio (\(-11.1\) dB) are observed. For Trajectory 1 (with Path 1), the \(\psi_{\rm{ave}}\) at an altitude of 12 km is about \(3^{\circ}\) lower than that at an altitude of 3 km. On the other hand, the \(J_{\rm{ave}}/S_{\rm{ave}}\) ratio at 12 km is 0.6 dB higher than at 3 km. As altitude \(h_{\rm{i}}\) increases, \(\psi_{\rm{ave}}\) decreases and the \(J_{\rm{ave}}/S_{\rm{ave}}\) ratio increases slightly. These results show that the relative angle difference \(\psi\) between the LEO satellite and interference source is a critical factor for the \(J/S\) ratio. Figure 4:1 Relative angle difference \(\psi\) and \(J/S\) ratio results obtained by varying the altitude of the airborne interference source when the LEO satellite moves along Trajectory 3: (**a**) \(\psi\) for Path 1; (**b**) \(J/S\) ratio for Path 1; (**c**) \(\psi\) for Path 2; (**d**) \(J/S\) ratio for Path 2; (**e**) \(\psi\) for Path 3; (**f**) \(J/S\) ratio for Path 3.