Impact of Ground-Based Interferences on GNSS Space Receivers On-Board LEO Satellites

The impact of GNSS (Global Navigation Satellite System) interference on terrestrial applications, such as aviation, maritime and automotive, has been widely studied. Recently, these studies have also started to report impact on GNSS space receivers on-board LEO (Low Earth Orbit) satellites (e.g. Wu (2024)). Most of the studies address the impact of GNSS interference in GNSS remote sensing applications, such as on GNSS-RO (GNSS Radio Occultation) and GNSS-R (GNSS Reflectometry) missions. However, the impact of GNSS interference on POD (Precise Orbit Determination) and TS (Time Synchronization) remains widely unexplored. Recently, an impact of ground-based interference on GNSS space receiver on-board the NorSat-TD CubeSat mission was reported in Bartle et al. (2024). Such impacts are of concern for high criticality LEO missions that rely on POD products (Selvan et al., 2023), such as Swarm (A, B and C), GRACE, GRACE-FO, and Sentinels. Additionally, many current or upcoming missions and mega-constellations in LEO might rely on GNSS for real-time and post-processed POD as well as for real-time TS. These missions include Earth Observation (EO), Navigation, and Telecommunications. Unlike remote sensing mission, these missions have GNSS antennas pointing in the zenith direction, which may mean that the interference has lower impact than in the case of GNSS-RO/GNSS-R where the antennas are pointing to the Earth’s limb or towards the Earth. In any case, it is necessary to assess the impact of GNSS interference on these missions and if needed, develop adequate detection and mitigation strategies. This paper will address the impact of ground-based interference on GNSS receivers on-board of several LEO missions (Swarm and Sentinel) for post-processed POD and TS (from now on PODTS) and for real-time PODTS.