Enhancing GNSS Software Receiver Robustness Against Jamming with Kalman Filter Predictions

In contemporary society, Global Navigation Satellite System (GNSS) applications have a widespread influence across diverse sectors, shaping various aspects of modern life. From aviation and environmental monitoring to marine navigation, space exploration, mapping, location determination, communication network timing, and military operations, the ubiquity of GPS technology underscores its significance in critical domains.Common challenges associated with GNSS signals include the Doppler effect and signal strength below the thermal noise level, largely stemming from the considerable distances between satellites and receivers and the high-speed motion of satellite transmitters. The Doppler effect induces a frequency shift in the signal, increasing signal processing challenges for receivers.The complexity of these challenges is particularly noticeable in aviation scenarios, given the high velocity of aircraft. Consequently, the resilience of GNSS receivers becomes paramount, necessitating robust operation even under adverse conditions such as signal loss or intentional jamming.This paper focuses on enhancing the resilience of a Software Defined Radio (SDR) GNSS receiver, specifically the FGI-GSRx from the Finnish Geospatial Research Institute. We simulate a GNSS signal outage or intentional jamming by intentionally jamming a transmitted signal to the receiver. To enhance the receiver’s resilience, we expand the standard tracking loops with a Kalman Filter (KF). The KF is designed to predict Doppler shift, enabling the receiver to promptly resume the tracking phase upon signal rediscovery, thereby obviating the need for reacquisition.It is worth noting that disrupting the receiver to force it into reacquisition represents a straightforward method of deceiving the target receiver with a false signal, redirecting it onto a different trajectory.