# Wide-Band Interference Mitigation in GNSS Receivers Using Sub-Band Automatic Gain Control +
## 5 Results
### Position Results  
Figure 13 shows the horizontal position error for the fast chirp tests. First, in Figure 13a, the PVT over time is shown. As the interference power increases, several receivers either result in large position errors, stable error, or give no position output. The first two cases of large or stable errors relate to the internal navigation filter that either drifts away or keeps the last \"known\" position for as long as possible. However, if the receiver cannot calculate a position sufficiently long, it eventually outputs no PVT solution. Further, the legend in this figure also shows the availability percentage of a PVT, but note that the availability is heavily degraded by the lag introduced by the navigation filters, which output a PVT for several seconds or minutes even though no new PVT could be calculated. Nevertheless, it shows the position performance under different circumstances. Second, Figure 13b shows the horizontal error cumulative distribution function (CDF) of the available PVT solutions. It indicates how accurate the different receivers are, whether the interference has an impact or not. The legend also displays the 50 % circular error probable (CEP) and the R-95 [28]. In this case, the CEP-50 for all receivers is below 75 cm, and the R-95 is below 5 m, indicating that several receivers have problems with outliers resulting from the interference signals. As expected, the best performing receiver is the HE \"Roof antenna\" and shows an R-95 significantly below 50 cm (it does a stand-alone PVT without additional assistance or corrections save satellite-based augmentation system (SBAS) corrections). Generally, the HE receivers have superior accuracy to the LC ones, as is expected in a geodetic-grade receiver with a superior RFFE, advanced tracking methods, and position filters. The position plots of the horizontal error over time and the CDF for all interference types are available in the Appendix C for additional reference. The availability percentage of a PVT is shown in Table 2. The HE and LC \"Roof antenna\" provide both almost 100 % for all interference types (there is a single 99.9 % availability exception for the LC), showing essentially no outages or issues during the tests. The HE \"No IM\" had a PVT availability between 30 % and 66 %, whereas the LC had between 50 % and 82 %. It could be that the LC receiver could keep the navigation filters active for a longer time, which adds some uncertainty to the results. Another reason could be the fact that the LC receiver is a narrow-band receiver, which suppresses out-of-band interference in the analog domain--significantly limiting saturation and degradation effects. Figure 12: Interference #9: Delta \(C/N_{0}\) for pulsed noise with 100 μs pulse width and 35 MHz bandwidth. The HE \"with IM\" (35% to 100% availability) significantly improved the performance in most cases, but the 4 MHz noise decreased the performance. The HDDM-AGC (28% to \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline
**Interference** & \multicolumn{3}{c}{**High-End (HE)**} & \multicolumn{3}{c}{**Low-Cost (LC)**} \\
**Number** & **Roof** & **No IM** & **With IM** & **HDDM** & **Roof** & **No IM** & **HDDM** \\ \hline \#1 CW & 100 & 30.5 & 100 & 28.7 & 100 & 71.1 & 68.9 \\ \#2 Fast Chirp & 100 & 51.6 & 74.8 & 64.0 & 99.9 & 56.3 & 90.3 \\ \#3 Slow Chirp & 100 & 35.5 & 75.5 & 72.9 & 100 & 81.1 & 90.7 \\ \#4 Fast Hop & 100 & 59.5 & 100 & 70.5 & 100 & 83.0 & 84.2 \\ \#5 Slow Hop & 100 & 58.0 & 100 & 67.4 & 100 & 75.3 & 97.4 \\ \#6 4 MHz Noise & 100 & 43.5 & 35.3 & 40.0 & 100 & 51.0 & 48.5 \\ \#7 35 MHz Noise & 100 & 56.5 & 57.5 & 43.8 & 100 & 82.3 & 83.9 \\ \#8 Slow Pulse & 100 & 65.6 & 66.8 & 100 & 100 & 77.5 & 100 \\ \#9 Fast Pulse & 100 & 64.4 & 86.8 & 100 & 100 & 60.4 & 99.7 \\ \hline Min. \#1 to \#9 & 100 & 30.5 & 35.3 & 28.7 & 99.9 & 51.0 & 48.5 \\ Mean \#1 to \#9 & 100 & 51.7 & 77.4 & 65.3 & 100 & 70.9 & 84.8 \\ Max. \#1 to \#9 & 100 & 65.6 & 100 & 100 & 100 & 83.0 & 100 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Percent availability.