The ships were initially classified only as attack carriers but have been constructed with anti-submarine capabilities since "Carl Vinson". These improvements include more advanced radar systems and facilities which enable the ships to operate aircraft in a more effective anti-submarine warfare role, including the fitting of common undersea picture (CUP) technology which uses sonar to allow for better assessment of the threat from submarines. The changes included better support for S-3 Viking ASW patrol planes and SH-60F Seahawk helicopters with dipping sonar systems.