Table 2.

Classification and mission of the US Navy standard USV [47].

Class	Description
X-class (small, ~3 m)	Special operation forces (SOF) support Depends on the missions’ inexpensive consumables, specially built and served with unimportant details (high-level sonar and lidar, etc.) Not standardized and made for specific purposes Maritime interdiction operation missions ‘Low-end’ ISR L and B from 11 M rigid inflatable boat or combat rubber raiding craft
Harbor class (7 m)	Size of a boat on most naval vessels used for maritime security Performs most basic tasks ISR/gun payloads Mine countermeasure (MCM) delivery Surface warfare (SUW) SOF support
Snorkeler class (7 m SS)	Works more reliably than do other USVs on the high seas MCM search ASW (maritime shield) Special missions support (stealthy profile)
Fleet class (11 m)	Planar or semiplanar hull Durable because of usage MCM sweep Maritime shield SUW, gun and torpedo “High-end” SOF High power electronic warfare