India and Japan unveiled their first-ever defence co‑development project — the Naval Radio Antenna system UNICORN (Unified Complex Radio Antenna / NORA‑50 integration mast) — marking what Prime Minister Narendra Modi called a new chapter in bilateral defence technology cooperation.

The announcement came during a joint appearance with Japanese Prime Minister Sanae Takaichi in New Delhi on Thursday and underlines both countries’ push to deepen defence industrial ties while strengthening regional maritime security.

What UNICORN is and why it matters to India?

UNICORN replaces conventional warship antenna farms — dozens of exposed sensors and transmitters that have historically been strong radar reflectors — with a single integrated radar dome (radome) that houses multiple antenna systems. By stacking and enclosing elements such as tactical data-link antennas, TACAN (Tactical Air Navigation System), communications, IFF (Identification Friend or Foe) units, and Electronic Support Measures (ESM) for radar and communications interception inside a low‑radar‑cross‑section (RCS) radome, UNICORN sharply reduces a ship’s electromagnetic signature. That reduction makes the mast — once one of the brightest radar returns on a warship — far harder for an adversary to detect, classify, and track.

Key features of UNICORN mast:

  • Link 16 antenna — supports the NATO/WEST actical data‑link network for secure, real‑time situational awareness and datasharing.
  • TACAN antenna — provides bearing and range to ship‑based helicopters for navigation and approach.
  • IFF antennas — Identification Friend or Foe systems for friend/enemy aircraft and platform identification.
  • ESM (ES‑R) — electronic support measure for radar detection; picks up radar emissions such as seekers from incoming anti‑ship missiles.
  • ESM (ES‑C) — electronic support measure for communications; intercepts radio communications (functionally similar to C‑ESM used by some European navies).
  • UHF/VHF Tx/Rx antenna — UHF/VHF transceive capability for short‑range voice and data communications.
  • ORQ‑2B‑4 Offshore Wireless Router — Wi‑Fi band router enabling data sharing, used during bistatic/multistatic sonar operations.

Joint technology, industrial roles

Japan brings advanced design expertise to the project, while India’s Bharat Electronics Limited (BEL) will handle integration and co‑production under the agreement. The arrangement is framed by India’s Make in India initiative, enabling domestic manufacturing of an advanced stealth mast for Indian naval platforms.

UNICORN was originally developed in Japan by NEC Corporation (lead contractor), Sampa Kogyo KK, and The Yokohama Rubber Co., Ltd., and is already fitted on Japan Maritime Self‑Defense Force (JMSDF) Mogami‑class stealth frigates.

New chapter in defence technology: PM Modi

The UNICORN project follows a November 2024 Memorandum of Implementation signed in Tokyo for co‑development and co‑production of the masts for Indian Navy ships; political consent first arose during the India–Japan 2+2 Ministerial Meeting in September 2022. Prime Minister Modi emphasised the strategic significance: the project will “jointly develop defence technologies that strengthen regional peace, maritime security, and the rules‑based order.”

“In the defence sector, we have signed an agreement today on the first co-development project between India and Japan. This project–involving the Naval Radio Antenna ‘UNICORN ‘- will open a new chapter in our defence technology partnership. We will now jointly develop defence technologies that strengthen regional peace, maritime security, and the rules-based order,” PM Modi said.

Japan’s decision to export defence equipment follows its 2014 revision of the “Three Principles on Transfer of Defense Equipment and Technology,” which loosened earlier restrictions and has enabled selective transfers, such as air‑surveillance radars to the Philippines in 2023.

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Defence analysts point to UNICORN’s most consequential benefit: stealth. In regions where maritime surveillance and ship identification heavily rely on radar fingerprinting — notably the East and South China Seas — reducing per‑ship radar signatures complicates adversary targeting and tracking. The Mogami‑class frigates fitted with UNICORN already achieve an RCS reportedly two orders of magnitude smaller than comparable conventional frigates; the mast removes a conspicuous “sparkler” in the ship’s radar profile and denies opponents a distinctive signal pattern used for cataloguing individual hulls.

India–Japan UNICORN partnership strengthens naval modernisation

Speaking on the visit, Japan’s Prime Minister Sanae Takaichi framed the cooperation within a broader regional vision, “A free, prosperous, and rules‑based Indo‑Pacific is our shared priority.” The language echoes other strategic partners’ Indo‑Pacific rhetoric and signals a coordinated push to strengthen defence capabilities among like‑minded democracies. For India, joint development with Japan advances domestic defence manufacturing, accelerates technology transfer, and enhances the Indian Navy’s platform survivability and operational effectiveness.

UNICORN integrates multiple subsystems in a compact mast: tactical data links for networked operations, TACAN for navigation and air control, communications suites, IFF transponders for friend/foe identification and ESM sensors for interception and situational awareness. Consolidation reduces electromagnetic interference between systems, improves sensor performance through optimized placement and shielding, and simplifies maintenance and logistics onboard.

Under the agreement, BEL will lead co‑production in India, with Japanese partners supplying core designs and technology transfer. The co‑development will progress from detailed design reviews and trials to prototyping, testing aboard Indian naval platforms, and eventual serial integration. The collaboration is expected to include training, sustainment planning, and supply‑chain integration to ensure operational readiness and lifecycle support.

For both capitals, UNICORN is a concrete symbol of deepening defence ties: it signals Japan’s readiness to share sensitive naval technology and India’s aim to indigenise critical defence systems while forging secure supply chains. Observers say the mast will strengthen India’s capacity to operate stealthier surface combatants in the Indian Ocean Region and contribute to collective deterrence and maritime domain awareness among partners.