US Chart No. 1

U.S. Chart No. 1 contains Symbols, Abbreviations and Terms used on Paper and Electronic Navigational Charts. 

AIS Aids to Navigation AIS transmitters can be affixed to a floating or fixed aid to navigation (ATON), such as a buoy, beacon, or light. The AIS broadcast provides the position and purpose of an aid, such as a port or starboard lateral buoy, even before it is close enough to be visible from a ship or to provide a radar return. This can help mariners confirm their ship's position or to prepare to make a turn that is based on passing a particular aid.