Unattended Ground Sensors (UGSs) are classified into diverse categories based on their design, operational principles, and deployment scenarios:Sensor Type: Seismic: Detects subtle vibrations in the ground caused by human footsteps, vehicle movements, or seismic activities. Acoustic: Captures and analyzes sound signatures to identify specific threats, such as approaching vehicles or weapons fire. Magnetic: Measures variations in magnetic fields to detect buried metal objects, such as concealed weapons or underground infrastructure. Infrared: Detects heat signatures emitted by humans, vehicles, or other warm objects, enabling surveillance in low-visibility conditions. Deployment: Air-Delivered: Designed to be dropped from aircraft or drones, allowing for rapid deployment in remote or inaccessible areas. Hand-Emplaced: Manually placed on the ground for long-term monitoring and surveillance, typically in fixed or concealed locations.