traffic baton light installed on some beacon of a class of traffic lights

traffic baton light installed on some beacon of a class of traffic lights, night lights emit predetermined color and flash frequency irradiation angle and visibility distance (frequency can be 0), reaches a predetermined, for nocturnal ship guidelines. Beacon lights fixed beacon, four kinds of light buoys, lightships and lighthouses. Fixed beacons, light buoys and lightships were for navigation and warning beacons used.
A lighthouse can identify signals day and night at sea for vessels measuring position and provide hazard warning to ships. Red indicates there is shallow, green there are rocks,yellow beacon light regardless of the color of two lights between the fairway.