# Evaluating GNSS Receiver Resilience: A Study on Simulation Environment Repeatability
## 5 Results
Charts (**a,c**) depict the receivers’ performance without jamming, while charts (**b,d**) show the impact of three-frequency jamming at \(-\)70 dBm on the MAX-M10 and NEO-6M, respectively. As demonstrated in Figure 10, the U-blox 10-Series receiver showcases enhanced performance, in part due to its ability to receive signals from all four GNSS constellations (GPS, GLONASS, Galileo, BeiDou), unlike the GPS-only U-blox 6-Series (Figure 9a). This broader GNSS support, combined with internal adaptive notch filters and digitally adjustable gain amplifiers, enables effective mitigation of CW interference at \(-50\) dBm, a level 20 dB higher (100 times more powerful) than the older generation could withstand. Despite an initial, brief accuracy loss, the position deviation remains largely within a 2 m radius, indicating robust performance under significantly stronger jamming. While evaluating individual measurement deviations over time offers some insight, it is challenging to identify overall response trends when faced with numerous curves. Figures 8-10 lack the clarity necessary to easily discern patterns in the GNSS receivers' responses. In accordance with the statistically-driven assessment strategy proposed in this article, it is essential to process the raw measurements to reveal underlying trends. The most reliable approach identified during our measurements involved observing the median value across all repetitions and visualizing the standard deviation of the measurement set. The detailed implementation of this statistical analysis is provided in Appendix A. Consequently, Figure 11 offers a significantly clearer perspective on the GP01 receiver's response to a stronger jamming signal (\(-45\) dBm) by displaying the median of all repeated measurements alongside their standard deviation. The shaded area around the median effectively represents the spread of individual measurements (which obscured patterns in the cluttered curves of earlier figures), with a wider area indicating greater variability between repetitions. The red vertical dashed lines indicate the interference period, and  
Figure 8: Position vector amplitude deviation from a static reference for 50 responses of a U-blox NEO-6M GNSS module. (**a**) No interference. (**b**) With \(-70\) dBm FM interference (red shaded area). this consolidated view dramatically enhances readability compared to the previously cluttered plots. As anticipated, the deviation remains minimal in the absence of interference (green curve), showing almost no increase over time. However, single-frequency (blue curve) and three-frequency (orange curve) CW jamming produce distinct patterns. Single-frequency interference results in a smaller position deviation, but the median deviates further away from the reference location. Conversely, three-frequency interference exhibits greater result dispersion (uncertainty), yet appropriate averaging allows for a closer approximation of the true position. Figure 12 presents a compelling comparison of all three GNSS receivers studied in this research under three-frequency interference at equal power levels. Here, the GP01 receiver demonstrates superior performance, maintaining a median close to the true value despite a gradual increase in deviation over time. By contrast, the older U-blox 6-Series generation fails under such high interference levels. Its software is unable to mitigate the interference, leading to inaccurate location calculations. The receiver only regains its location fix after the interference ceases. Figure 9: The U-blox NEO-6M’s performance under two interference scenarios: (**a**) continuous wave (CW) interference at \(-70\) dBm and (**b**) three-frequency interference at \(-70\) dBm. The red shaded regions represent the time intervals during which interference was present. Lastly, Figure 13 addresses our core research question by illustrating receiver performance in a diverse jamming environment near its operational limits. Under these conditions, interference degrades position accuracy without a complete operational halt.