## 3 Classification Based on Function  
A significant number of sensors are being used during emergency situations based on their function, flight time, and usefulness. The benefits and limitations of those sensors are reviewed and analyzed in the following sections and Table 2. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Example** & **Type** & **Application Time** & **Theory** & **Height of Application** \\ \hline UAV & Communication support & Provides & It is equipped with photoelectric & \\  & & & detection pod, synthetic aperture radar, & \\  & & & aerial CCD camera, emergency & \\  & & & communication support pod, & \\  & & & emergency delivery pod and other & \\  & & & equipment to provide communication & \\  & & & support and obtain front-line & \\  & & & information. & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._ \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Main Categories** & **Sub Categories** & **Benefits** & **Constraints** \\ \hline \multirow{7}{*}{Life Detection} & Acoustic & Non-invasive and can penetrate metal walls. & Limited applicability \\  & & Real-time, portable, and wide range. & High false positive rate \\  & & & Limited specificity \\ \cline{2-4}  & \multirow{3}{*}{Optical} & Non-invasive, real-time, and portable. & Limited scope \\  & & Provides highly accurate measurements of vital & Environmental sensitivity \\  & & signs to avoid moving a collapsed building. & & \\ \cline{2-4}  & \multirow{3}{*}{Radar} & Non-invasive, real-time, and robust. & Limited scope \\  & & Radar can sense through walls and other barriers & Privacy concerns \\  & & that might block an optical signal. & & \\ \cline{2-4}  & \multirow{3}{*}{Volatile organic compounds (VOCs)} & Non-invasive and sensitive. & False positives \\  & & VOC detection can be used in a wide range of & Lack of specificity \\  & & environments, including air, water, soil, and rocks. & Sampling difficulties \\ \hline \multirow{7}{*}{Gravity} & Non-invasive and cost-effective. & Limited sensitivity \\  & & Gravity seismic monitoring can provide & Limited depth range \\  & & high-resolution data on subsurface geology and & Limited temporal resolution \\  & & fluid movements. & & Technical challenges \\ \hline \multirow{7}{*}{Micro-electromechanical systems (MEMS)} & Cost-effective, compact size, and low power consumption. & & \\  & MEMS sensors are small and lightweight, which & Limited frequency range \\  & & makes them easy to install and transport in & Limited lifespan \\  & & wide areas. & Sensitivity to environmental factors \\  & & MEMS sensors offer high-resolution data that can & \\  & & capture small movements in the ground. & \\ \hline \multirow{7}{*}{Seismic monitoring} & \multirow{3}{*}{Distributed Acoustic Sensing (DAS)} & Continuous monitoring and low power consumption. & High cost \\  & & & Limited frequency range \\ \cline{1-1}  & & DAS offers high-resolution data that can capture & Calibration requirements \\ \cline{1-1}  & & small movements in the ground. & Sensitivity to environmental factors \\ \hline \multirow{7}{*}{Wi-Fi} & \multirow{3}{*}{Cost-effective, easy installation, and continuous monitoring.} & Limited range \\ \cline{1-1}  & & & \\ \cline{1-1}  & & Wi-Fi sensors require minimal maintenance, as they are not affected by environmental factors such & \\ \cline{1-1}  & & as temperature changes and humidity. & \\ \cline{1-1} \cline{2-4}  & \multirow{3}{*}{Long-Term Evolution (LTE)} & Cost-effective, remote access, and real-time data transmission. & Limited data quality \\ \cline{1-1}  & & LTE networks cover large areas, which makes it & Dependence on cellular networks \\ \cline{1-1}  & & possible to collect seismic data widely. & Lack of historical data \\ \hline \multirow{7}{*}{Synthetic Aperture Radar (SAR)} & Wide range for tracking the movement of ground. & & \\ \cline{1-1}  & & High-resolution images. & \\ \cline{1-1}  & & & Data processing complex and \\ \cline{1-1}  & & & Earth’s surface. & time-consuming \\ \hline \end{tabular}
\end{table}