Navy chooses circular antenna array from BAE Systems for shipboard identification-friend-or-foe (IFF) system

March 31, 2022
Antennas are for the AN/UPX-29 shipboard interrogator, which is a centralized IFF system that identifies friendly ships and aircraft in crowded areas.

PATUXENT RIVER NAS, Md. – U.S. Navy aerial warfare systems experts needed special circular shipboard antenna arrays for the AN/UPX-29(V) identification-friend-or-foe (IFF) interrogator system aboard surface warships. They found their solution from the BAE Systems Electronic Systems segment in Nashua, N.H.

Officials of the Naval Air Systems Command at Patuxent River Naval Air Station, Md., announced a $13 million order to BAE Systems on Tuesday to provide six OE-120B electronically steerable antenna (ESA) groups.

The BAE Systems OE-120 antenna group is an electronically steerable antenna that shipboard operators can redirect within 50 microseconds to interrogate any target on the horizon. The antenna array supports IFF interrogator as well as air traffic control beacon systems, and is designed for surface ships and land-based installations.

The antennas are for the AN/UPX-29 shipboard interrogator, which is a centralized IFF system that employs a challenge and reply technique to distinguish friendly platforms in a multi-target environment.

Related: BAE to provide Navy shipboard IFF interrogators to identify friendly and enemy aircraft

This contract modification exercises an option to procure six OE-120B antenna groups -- four for the Navy and one for the government of Canada; and four OE-120B antenna group retrofit kits for the Navy and associated data.

The antenna group supports a wide range of systems, including IFF, secondary surveillance radar, and air traffic control radar. The system offers constant fleet protection for navies around the world.

The OE-120B antenna groups offer instantaneous, multiple target identification supports defense against today’s sophisticated air threats. It accommodates all standard IFF modes.

The antenna system adapts to land and sea applications to support a variety of mission environments, and its electronically steered system architecture offers increased reliability and reduced maintenance. Its array configuration allows for smooth performance degradation in the event of a failure.

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The OE-120 electronically steerable antenna is suitable for the Navy's Ticonderoga-class cruiser (CG 47), the Arleigh Burke-class destroyer (DDG 51), the Wasp-class amphibious assault ship (LHD 1), the San Antonio-class amphibious transport dock (LPD 17), aircraft carriers, and the Japanese Kongo-class destroyer (FMS DD 173) -- a version of the U.S. Burke-class destroyer.

The AN/UPX-29(V) shipboard IFF interrogator, for which the OE-120B antenna is part, distinguishes friendly vessels and aircraft nearby during combat operations.

The AN/UPX-29(V) can process and store as man as 400 targets, provide instantaneous interrogation on a target within 25 microseconds, electronically evaluate Mode 4 replies, call up operator-designated target information, display IFF targets synchronized with as many as four radars at 22 displays, and interface with shipboard computers.

At the heart of the OE-120 system is the AS-3134/UPX antenna array, which consists of 64 vertical radiating dipole antenna element pairs arranged in a circle on the ship's mast. The system uses electronic beam steering to scan all areas around the ship. The dipole antenna element pairs can produce either directional or omnidirectional beam patterns.

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The system can aim its RF energy at any target of interest located at any point on the horizon within microseconds. Operators also can scan the antenna's output rapidly over a designated sector of interest. During normal surveillance operations the antenna group scans the horizon at 90 revolutions per second.

The OE-120's CV-3372/UPX antenna positioner receives commands from the C-10063/UPX controller, distributes RF power to the radiators, and digitally controls the system's output mode and boresight direction. The system's C-10063/UPX antenna controller, meanwhile, is located below decks and translates synchronized data continuously from the ship's environmental sensors.

On this order, BAE Systems engineers will do the work in Nashua, N.H., and should be finished by November 2024. For more information contact BAE Systems Electronic Systems online at, or Naval Air Systems Command at

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