# Functionality of the Search and Rescue Transponder (SART) in Maritime Search and Rescue Actions
## 3 Results
Figure 8: Radar screen showing the SART response signal at 2 Nm. When attempting to detect the device's signal at short distances (0.2-0.6 Nm), the radar image took various forms, making it impossible to clearly determine the bearing of the object (Figure 11). However, the signal was detected every time. Figure 11: Radar screen showing the SART response signal at 0.2 Nm. Figure 9: Radar screen showing the SART response signal at 1 Nm. Similar results were obtained for all other scenarios (Scenarios 2, 3, and 4). This indicates that there was no significant effect of the automatic radar settings or the presence of a radar reflector on the detection rate of the SART signal under the experimental conditions studied. The auto mode function adapts to weather conditions. During the research, these conditions were relatively favorable. It can therefore be assumed that the auto settings for sea or rain clutter were set to very low values. The reduction of interference from waves or wind was not needed, and the radar only eliminated it to a minor extent. The effectiveness calculations for A1 (detectability) and A2 (echolocation) were made according to Formula (1). For this calculation, 20 trials were used (four trials at a distance of 4 Nm, four trials at a distance of 3 Nm, four trials at a distance of 2 Nm, four trials at a distance of 1 Nm, and four trials at a distance of less than 1 nautical mile). The results of the calculations are shown in Figure 12. The device signal detection effectiveness (A1) is 100%. All attempts across all distance ranges were successful. The echo distinctiveness effectiveness (A2) during the signal detection moment (location of the liferaft) is 80%. Attempts to separate the echo were not possible in one distance range (the closest to the device). It should be noted that when approaching an object with an already detected SART signal and when the signal changes into circles, it was not possible to distinguish the echo every time. Therefore, the effectiveness drops from 80% to 0% at this point. The effectiveness calculation for A3 (shape compatibility) was made according to formulas (2) and (3) for three distance intervals: 4 Nm and more (expected dots), 1-3 Nm (expected arcs), and less than 1 Nm (expected circles, according to the instructions). The shape effectiveness is 66.67%. Shape incompatibility was noted in the middle-distance range (between 1 and 3 Nm). The amount of interference (A4) associated with the reception of the SART device signal is shown in Figure 13. At distances greater than 1 Nm, interference is described as weak. The reception signal of the SART device covers the image only along the bearing line, which may still cause some difficulty in assessing the echoes of other ships or objects on the same bearing. In general, these can be described as minor but require special attention from the navigator. At ranges below 1 nautical mile, there is a rapid decrease in image readability. The entire screen becomes covered by extensive rings of echoes. Figure 12: Effectiveness of the SART device. In each trial, the navigator assessed the percentage of image clarity. The results of this assessment are shown in Figure 14. It can be seen that the image quality remains good (above 80%) most of the time. The SART response signal occupies a narrow sector of the radar image when the device is detected at distances greater than 1 nautical mile. As the vessel approaches, the amount of interference increases significantly. The diagram also includes an assessment of the ability to distinguish life raft echoes, which decreases significantly at distances below approximately 0.8 nautical miles.