# Functionality of the Search and Rescue Transponder (SART) in Maritime Search and Rescue Actions
## 2 Materials and Methods
To determine the ability to acquire and track echoes under different conditions. The research was conducted in the Bay of Pomerania in the Baltic Sea (Figure 4) in 2024, at geographic coordinates \(\varphi=54^{\circ}36.8^{\prime}\) N; \(\lambda=14^{\circ}41.6^{\prime}\) E. The search target was a liferaft equipped with a S4 Rescue SART device (McMurdo Portsmouth, UK). The SART device was positioned 1.5 m above the sea surface. A 15-m-long vessel equipped with an X-band Raymarine radar was used for the survey. The radar antenna was mounted at a height of 6 m above the sea surface, while the observer's eyes were positioned at a height of 3 m. The vessel used in the experiment is a search and rescue type, actively engaged in daily service. This medium-sized vessel is primarily designed for search operations, survivor recovery, casualty transport, and towing. It is optimally equipped for effective operations, particularly for search activities. The antenna height is not significant and differs from that of typical cargo or passenger vessels, which may affect the reception of the SART response signal. The external conditions during the experiment were as follows: sea state 2, wind from the northeast at 5 m/s, very good visibility, a temperature of 19 \({}^{\circ}\)C, and a partly cloudy sky. During the experiment, four scenarios were tested (Table 1). The scenarios took into account different radar settings (manual and automatic) and the use of a radar reflector. Each  
Figure 4: Area of research (red rectangle). scenario was performed six times, with the rescue vessel and the search target deployed at varying distances ranging from 0.2 to 4 nautical miles. Conducting various scenarios allowed each combination of settings to be tested separately. Situations involving non-compliant installation of the device were avoided during the experiment. According to the manufacturer's instructions, the SART device should not be used at a height of less than 1 m above the water surface. During the tests, the device was placed at a height of 1.5 m and no farther than 6 nautical miles from the ship. The scenarios were conducted following the procedure shown in Figure 5.  
The stages of the procedure are a key part of any scenario. Maintaining the order of the phases ensured that the experimental conditions were repeatable. Descriptions of the stages are provided in Table 2. A detailed explanation is given below the table. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Scenario** & **Radar Settings** & **Radar Reflector** & **Distance** \\  & & & [**Nm**] \\ \hline Scenario 1 & Manual & No & 0.2–4 \\ Scenario 2 & Auto & No & 0.2–4 \\ Scenario 3 & Manual & Yes & 0.2–4 \\ Scenario 4 & Auto & Yes & 0.2–4 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Main assumptions of the scenarios. Figure 5: Experiment procedure. The ability to communicate is crucial for safety during work at sea. The assisting boat and the rescue vessel must move away from each other. When the planned distance is reached, the rescue vessel gives the command to activate the SART. Communication procedures include the communication channel, backup channel, commands, responses, and a \"code word\" for aborting the exercise in case of an emergency. The crews of both vessels are equipped with individual lifesaving devices. Detection and tracking of the SART device occur at different distances. In the experiment, each scenario was performed six times at distances ranging from 0.2 to 4 nautical miles. Radar interference or lack of detection will be assessed in this study. As explained earlier, the manual option involves the user adjusting the radar to the prevailing conditions, while the auto mode adjusts these settings automatically. The purpose of a radar reflector is to amplify the echo signal of an object (in this case, a liferaft) detected by radar. The radar reflector consists of several sections arranged perpendicular to each other. A radar reflector is provided with the liferaft equipment.