## 3 Results
### Case Study: Starlink Constellation (Inter-Satellite LEO-LEO Link)  
Starlink is a mega-constellation of LEO satellites designed to revolutionize global communications by providing high-speed internet to remote areas. In addition, the network has significant potential for applications in the field of positioning, navigation, and timing (PNT), offering advantages such as higher bandwidths, increased power, and increased resilience against jamming and spoofing attacks. With over 7000 satellites already launched, Starlink is the most advanced LEO constellation in the world. Technical analysis of the Starlink signals revealed the following main parameters: the frequency used is in the Ku band, between 10.7 and 12.7 GHz, with a bandwidth per channel of approximately 200 MHz. The system uses an antenna with a nominal gain of 40 dBi, and losses due to polarization mismatch and incorrect feed horn alignment are estimated at 4-5 dB. The signal is modulated using OFDM, which allows efficient use of the spectrum and reduces inter-symbol interference by adding a cyclic prefix. The system is also affected by Doppler effects due to the rapid movement of satellites in low orbit, which requires complex corrections for frequency and time synchronization. The antenna used to capture signals has a directional aperture of approximately 3 degrees and is connected to a low noise block (LNB) with a conversion gain of 60 dB and a noise figure of 0.8 dB [28]. These technical characteristics make Starlink a platform for the global internet because satellite internet services and mobile satellite communications are transforming global connectivity by leveraging constellations of satellites in low Earth orbit. Starlink provides high-speed broadband access to remote areas and enables mobile communications across vast regions where terrestrial infrastructure is limited. Satellite internet services focus on providing reliable, high-bandwidth connections for personal, commercial, and government use, while mobile satellite communications facilitate voice and data transmission for mobile devices globally. Both technologies rely on advanced signal processing techniques, robust hardware design, and efficient modulation schemes to overcome challenges such as Doppler effects, atmospheric interference, and latency. Together, they represent a critical step toward universal connectivity and enhanced global communications capabilities. A representation of the Starlink constellation is shown in Figure 13.  
For the Starlink analysis, in Table 12, we highlighted the coordinates of the two satellites used for the LEO-LEO communication link, and in Table 13 we highlighted the  
Figure 12: Link margin vs. modulation scheme for LEO-GEO connection. parameters of the Starlink transmitter, Starlink receiver, and the link, which are real values that are present in the Starlink connection based on the findings from [28; 29]. There is no public information regarding the type of correction used by the Starlink satellites. Thus, in the analysis, we considered the OFDM modulation used by the satellites in combination with the 4 types of correction codes discussed in the previous sections, and the results can be seen in Figure 14.  
It would seem that all codes provide sufficient margin for transmitting information, with the Golay code providing the best results. Given that much technical information is not public, it is possible that satellites use more advanced correction schemes or multiple algorithms combined.