A surface-search radar, sometimes more accurately known as a sea-surface-search radar or naval surveillance radar, is a type of military

radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...

intended primarily to locate objects on the surface of lakes and oceans. Part of almost every modern naval ship, they are also widely used on

maritime patrol aircraft A maritime patrol aircraft (MPA), also known as a patrol aircraft, maritime reconnaissance aircraft, maritime surveillance aircraft, or by the older American term patrol bomber, is a fixed-wing aircraft designed to operate for long durations over ...

and naval

helicopter A helicopter is a type of rotorcraft in which Lift (force), lift and thrust are supplied by horizontally spinning Helicopter rotor, rotors. This allows the helicopter to VTOL, take off and land vertically, to hover (helicopter), hover, and ...

s. When mounted on an aircraft, they are sometimes known, in British terminology, as

air-to-surface-vessel radar Radar, Air to Surface Vessel, or ASV radar for short, is a classification used by the Royal Air Force (RAF) to refer to a series of aircraft-mounted radar systems used to scan the surface of the ocean to locate ships and surfaced submarines. The fi ...

— ASV for short. Similar radars are also widely used on civilian ships and even small pleasure craft, in which case they are more commonly known as

marine radar Marine radars are X band or S band radars on ships, used to detect other ships and land hazards, to provide bearing and distance for collision avoidance and navigation at sea. They are electronic navigation instruments that use a rotating a ...

. As with conventional surveillance radars, these systems detect objects from the reflections of

radio Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connec ...

signals off target objects, especially metal. The range of a surface-search radar is greatly increased compared to other roles due to several aspects of the sea surfaces and the objects in it. In low sea states, water makes an excellent reflector for radio signals, which helps maximize the signal strength as reflections off the water strike the targets in addition to the line-of-sight signal. Additionally, as the sides of ships generally rise vertically from the surface, they form partial

corner cube A corner reflector is a retroreflector consisting of three mutually perpendicular, intersecting flat reflective surfaces. It reflects waves incident from any direction directly towards the source, but translated. The three intersecting surfa ...

s which increases the returned signal. Offsetting these advantages is the fact that in higher sea states, large waves also create the same signals, making radar clutter a significant problem. A considerable amount of research into clutter reduction was applied to the naval market.

References

* {{tech-stub Radar

See also

References