Analysis of RFI From MEO Inter-Satellite Links to LEO Passive Sensors

Spaceborne passive sensing (SPS) has been crucial in obtaining the Earth's environmental and meteorological information. As its signal levels are significantly lower than those of communication systems, passive sensing bands need to be protected from radio frequency interference (RFI) of other transmission sources. Here, we investigate the RFI of inter-satellite links (ISLs) of an emerging mega-constellation medium earth orbit (MEO) satellite communication system to nadir-pointing low earth orbit (LEO) SPS. We develop accurate static and dynamic analytical RFI models by introducing static and time-varying virtual satellite distribution functions and the regions of line-of-sight RFI paths. Performance comparison between the proposed analytical approach and the simulation-based approach for various scenarios of MEO satellites and LEO SPS system settings corroborates the accuracy, flexibility, and generality of the proposed analytical models, and reveals insights into the corresponding RFI characteristics. The results also indicate that it is possible for MEO ISLs to utilize the SPS spectrum while keeping the RFI to the SPS at an acceptable level.