Stability of modern geodetic GNSS receivers in case ofjamming

Today, positioning and navigation systems play a vital role in numerous domains. These systems are known as Global Navigation Satellite Systems (GNSS). The main GNSS systems include GPS (USA), GLONASS (Russia), Galileo (European Union), and BeiDou (China). These systems are widely used not only in personal navigation applications but also in critical sectors such as defense, transportation, energy, agriculture, construction, and telecommunications. Given their extensive application areas, the reliability of GNSS systems is of critical importance. Due to the inherently weak structure of GNSS signals, these systems are highly vulnerable to external interferences. In particular, attacks such as jamming (signal interference) and spoofing (signal deception) can prevent GNSS receivers from detecting valid signals or can lead them to calculate false position data. These types of disruptions pose significant security threats, especially for military systems, unmanned vehicles, and other critical infrastructures that rely on GNSS-based services. In this thesis, the vulnerability of GNSS systems to jamming and spoofing attacks is examined experimentally. Within the scope of the experimental study, GNSS signals were intentionally disrupted from specific distances using Adalm Pluto and HackRF One devices to simulate jamming and spoofing conditions, and the impacts of these interventions on positioning accuracy were analyzed. Additionally, two different types of antennas Lora and 2.4 GHz were used to observe how antenna strength affects system susceptibility to such attacks. Both static and kinematic measurement scenarios were tested, and variations in position accuracy, signal quality, satellite tracking, and phase ambiguities were evaluated. The results reveal the sensitivity of GNSS systems to external signal threats and aim to provide foundational data for the development of effective countermeasure strategies. Keywords: GNSS, Jamming, Spoofing, Precise Point Positioning, SDR Algorithm, RealTime Kinematic Positioning