a marine buoy equipped with a radio transmitter with an omnidirectional antenna. It is used for navigational purposes to indicate, for example, navigation limits and locations dangerous for sailing. The signals emitted by a radio buoy are received by the ship’s radio direction finder, which determines the direction to the buoy.
The passive model of the radio buoy is the radar buoy—a moored marine buoy with highly reflective metal corner reflectors mounted on its upper section. It is employed for the same navigational purposes but can only be used by ships equipped with radar sets.