## 3 Results
### Statistical Analysis of AML Precision and Reliability  
To evaluate the measurement precision and statistical reliability of the AML system, a comprehensive analysis was conducted using deviation data obtained from 32 samples, each comprising 10 measurement points. As described in Section 3.2, each point includes 4 types of deviation values: \(\Delta\)RCP Position, \(\Delta\)RCP Depth, \(\Delta\)PE Position, and \(\Delta\)PE Depth. These data were subjected to a statistical assessment in terms of distribution symmetry, spread, and presence of outliers. Histogram-based analyses were performed to visualize the frequency distribution of the deviation values across all measurement points (\(n\) = 320 per type). Figure 8 presents the histograms for each deviation category, annotated with the mean and \(\pm\)1\(\sigma\) intervals. The RCP Position deviation (Figure 9a) exhibited a tight concentration around the mean value of +0.0161 m with a standard deviation of \(\pm\)0.0584 m, indicating high consis  
Figure 8: Heatmaps of AML measurement deviations for RCP and PE pipelines by position and depth, showing 32 samples \(\times\) 10 points with color intensity centered at zero to illustrate spatial accuracy and consistency. tency in horizontal localization. The RCP Depth deviation (Figure 9b) showed a slightly broader distribution with a mean of +0.0822 m and a standard deviation of \(\pm\)0.1213 m, suggesting slightly greater variability in vertical measurements, which is often influenced by soil compaction and the subsurface conditions. Despite their non-metallic nature and increased detection complexity, the detection of PE pipelines still exhibited excellent precision. The PE Position deviation (Figure 9c) had a near-zero mean of +0.0029 m with a standard deviation of \(\pm\)0.0619 m, confirming reliable horizontal detection. Similarly, the PE Depth deviation (Figure 9d) showed a mean of +0.0975 m and a standard deviation of \(\pm\)0.1154 m.  
These distributions approximate Gaussian behavior, implying that the AML's error characteristics are random and not skewed by systematic bias. This statistical stability enhances confidence in the reproducibility of the measurements and supports robust integration into field operations. In addition to visual analysis, root mean square error (RMSE) values were computed to quantify overall measurement accuracy, yielding 0.0602 m for RCP Position, 0.1268 m for RCP Depth, 0.0616 m for PE Position, and 0.1229 m for PE Depth. These low RMSE values reaffirm the AML's suitability for high-precision detection under regulatory constraints and fall well within the Korean legal tolerances specified in Table 3. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Measuring Equipment** & **Performance Specification** & **Remarks** \\ \hline Metallic and Non-metallic & Horizontal Position: \(\pm\)20 cm & Applicable to pipelines \\ Pipeline Detectors & Depth Accuracy: \(\pm\)30 cm & buried at 3 m depth \\ \hline \hline \end{tabular}
\end{table} 
Table 3: GPR equipment performance evaluation criteria as defined by South Korean regulations. Figure 9: Histograms of AML deviation values: (**a**) RCP Position, (**b**) RCP Depth, (**c**) PE Position, (**d**) PE Depth. The dashed vertical line indicates the mean, while dotted lines show \(\pm\)1\(\sigma\) intervals. From a practical perspective, the performance of the AML system reflects not only compliance with regulatory requirements but also technological innovation in subsurface utility detection. The system is capable of identifying both metallic and non-metallic utilities with sub-decimeter accuracy, making it a viable alternative to traditional Ground-Penetrating Radar (GPR) or Electromagnetic Induction (EMI) devices. In particular, the AML system can detect buried utilities at depths reaching up to 3 m, significantly surpassing the typical ~2 m effective detection range of most GPR systems under standard field conditions.