# Advancing Road Infrastructure Safety with the Remotely Piloted Safety Cone
## 3 Results
### Navigation  
The following is a series of tests designed to evaluate different sensor configurations on the trajectory tracking accuracy of RPSCs. Three consecutive trials were conducted to analyze the system's performance without sensors, with only encoders, and finally with encoders and RTK combined. Each configuration allowed for observing how the performance of the RPSC varies in terms of deviation from the planned path, providing information on each sensor's relative and complementary importance in real environments. In the first test, the RPSC operated without both RTK and encoders. In this configuration, an average deviation distance of 0.45 m and a standard deviation of 0.42 m were observed. The maximum deviation reached 1.75 m.  
Without the encoders, the RPSC lacks continuous feedback on its wheel movement, and the absence of RTK means it also does not receive precise absolute position corrections, as shown in Figure 11. In the top subfigure, the yellow segment represents the predefined  
Figure 10: Time-series analysis of horizontal positioning error for RPSC2 using SmartNet corrections. path for the RPSCs to follow, while the red segment shows the actual travelled route. This results in the RPSC navigating based on less accurate data, leading to larger and more variable deviations. The combined absence of both sensor types significantly compromises the RPSC's ability to maintain its planned route, as it lacks both the real-time correction capability of the encoders and the high-precision absolute correction provided by RTK. In the second test, the RPSC used encoders but did not have RTK support (Figure 12). The results showed an average deviation distance of 0.46 m and a standard deviation of 0.28 m. The maximum deviation was 1.32 m.  
Without the absolute correction RTK provides, the RPSC is forced to rely solely on encoders, which only provide relative information about movement. This data type can accumulate errors over time, known as drift. These accumulated errors manifest as larger deviations in the RPSC's route without an external correction source. Although the encoders help maintain consistency in the trajectory, the lack of absolute precision from RTK leads to significant deviations. The RPSC was equipped with both encoders and RTK from SmartNet in the third test. The results shown in Figure 13 illustrate an average deviation distance of 0.20 m, with a standard deviation of 0.14 m. The maximum recorded deviation was 0.75 m.  
Figure 11: View of the test field in contrast with the distance deviation evaluation without encoders and RTK. Figure 12: View of the test field in contrast with the distance deviation evaluation without RTK. Figure 13: View of the test field in contrast with the distance deviation evaluation with all sensors. This configuration, which combines encoders and RTK, offers the highest accuracy in positioning the RPSC. Encoders play a crucial role in maintaining control of the RPSC's movement by providing real-time feedback on its displacement. This information allows the RPSC to continuously adjust its trajectory and correct minor deviations immediately. On the other hand, RTK provides highly accurate absolute position correction. Integrating these two sensor types results in a robust and reliable system that minimises deviations, ensuring the RPSC stays as close to its planned route. When comparing the navigation tests, the combination of encoders and RTK offers the best route accuracy. Table 7, showing the statistical data for the different sensor configurations, highlights the differences between the tests. Measures of central tendency indicate that the RTK + Encoders configuration has the lowest mean (0.20 m) and median (0.17 m), suggesting high accuracy and consistency. In contrast, the No Sensors configuration shows a mean of 0.45 m and a median of 0.31 m, evidencing a significant increase in localisation uncertainty.