A method for detection of radio frequency interference effects on L band GNSS receiver positional accuracy

Global Navigation Satellite Systems (GNSS) provide accurate and reliable positioning and timing information to the users. However, GNSS signals are inherently weak due to their low transmission power, making them vulnerable to interference and intentional disruptions. Radio frequency interference (RFI) from man-made sources, such as intentional jamming and spoofing, as well as unintentional signal disruptions, can severely compromise the accuracy, availability, and integrity of GNSS services. Both threats highlight the vulnerability of GNSS-dependent systems and emphasize the importance of resilient receiver designs, monitoring, and countermeasures. In this paper, RFI detection and its effects on GNSS signal quality and positioning performance are investigated. To detect variations in the signal due to RFI, a cubic spline fitting method is employed to approximate the expected signal’s behavior. A total of 67 RFI events were identified from seven IGS GNSS stations, with a notable increase from 21 events in 2023 to 46 events in 2024 for SNR deviation and Precise Point Positioning (PPP) positioning error analysis. It is observed that the RFI due to positioning errors exceeds ±15–20 m during interference periods, with pronounced fluctuations in the afternoon hours. The analysis can be used to get a better idea of the effects of RFI and to continue developing better methods of monitoring GNSS and reducing its impact.