# Positioning Systems for Unmanned Underwater Vehicles: A Comprehensive Review
## 5 Results  
As detailed in Table 3, we categorized the citations based on these criteria: the type of paper (whether it is a journal article, conference paper, or review), the presence of INSs, the presence of DVL, or the use of other positioning systems, including instances where multiple systems were utilized together. This categorization helped us to systematically organize and evaluate the literature. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Reference** & **Type of Paper** & \begin{tabular}{c} **Inertial** \\ **Navigation System** \\ \end{tabular} & \
\begin{tabular}{c} **Doppler Velocity** \\ **Log** \\ \end{tabular} &
\begin{tabular}{c} **Other Positioning** \\ **System Used** \\ \end{tabular} & **Target Applications** \\ \hline
[15] & Article & ✓ & x & Light Detection and Ranging &
\begin{tabular}{c} Camera Improvement, \\ Underwater Mapping, \\ Deep-Sea Exploration \\ \end{tabular} \\ \hline
[103] & Article & x & x & Long Baseline System &
\begin{tabular}{c} Deep-sea Operations, \\ Subsea Mapping \\ \end{tabular} \\ \hline
[91] & Article & x & x & Gravity Gradiometry &
\begin{tabular}{c} Massive Subseafloor, \\ Deposits Detection \\ \end{tabular} \\ \hline
[39] & Conference Paper & ✓ & ✓ & \
\begin{tabular}{c} Global Navigation \\ Satellite System \\ \end{tabular} &
\begin{tabular}{c} Underwater Mining, \\ Operations Support \\ \end{tabular} \\ \hline
[52] & Journal & ✓ & ✓ & x &
\begin{tabular}{c} Seafloor Mapping, \\ INS enhancer \\ \end{tabular} \\ \hline
[104] & Journal & x & x & Ultra-Short Baseline & Underwater Coordination \\ \hline
[32] & Conference Paper & ✓ & x &
\begin{tabular}{c} Using Inertial \\ Measurement Units \\ \end{tabular} & Exploration in Hazardous Areas \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Analysis of navigation technologies and positioning systems in underwater studies. Furthermore, understanding the specific applications for which Unmanned Underwater Vehicles (UUVs) are designed was a key aspect of our review. Each UUV is built with particular objectives in mind, and identifying these applications was crucial for appreciating the relevance and significance of UUVs in various contexts. Some UUVs, as identified in our review, are designed to address multiple applications simultaneously. By uncovering these diverse applications, we gained insights into the broader impact and utility of UUVs in different scenarios. Overall, the process of categorizing the literature based on paper type and the positioning systems used, coupled with a detailed exploration of UUV applications, was essential for understanding the scope and significance of the research. This approach allowed us to create a well-organized framework for discussing the findings and implications of our review. A key aspect of positioning systems is their accuracy, which is influenced by various factors such as water conditions, terrain, depth, distance, noise, magnetic fields, and improper sensor calibration. These factors directly affect the positioning and navigation of Unmanned Underwater Vehicles (UUVs). Given the importance of accuracy in positioning systems, Table 4 was created to summarize the accuracy data discussed in Tables 3 and 4 from the referenced papers. The first column of Table 4 lists the references from which the data were sourced. The second column provides the numerical accuracy values, as reported by the authors, based on simulations, tests, and theoretical studies. Since accuracy depends