“…The positioning results of U1, when placed in an upright position, are shown in Figure 7, Figure 8, and Based on Figure 7, Figure 8, and Figure 9, the positioning points with the numbers (7,8,9,12,13,14,17,18,19), which are located in the central 3*3 square area, have relatively small positioning errors at depths of 30 cm, 50 cm, and 60 cm. The average absolute values of the specific positioning errors are shown in Table 2.…”