India and Japan have signed their first bilateral agreement for the joint development of defence equipment, marking a significant step forward in their growing strategic and security partnership.

According to Japan's Ministry of Foreign Affairs, the inaugural project under the agreement will focus on the development and licensed production of the UNICORN (Unified Complex Radio Antenna) shipborne communications mast, an advanced integrated mast system developed by Japan's NEC Corporation.

Under the arrangement, Bharat Electronics Limited (BEL) will manufacture the system in India in collaboration with Japanese partners. Japan will provide the design and core technologies, while India will undertake system integration, localisation and production in line with the government's "Make in India" initiative.

Although the UNICORN system was originally developed by NEC, India plans to integrate its own sensors and antennas into the mast for deployment on Indian Navy warships. The integrated mast is expected to gradually replace existing communication and sensor mast systems across the Navy's fleet.

India has shown interest in acquiring the technology for several years. In November 2024, the two countries concluded an agreement for the export of UNICORN multifunctional masts to India under their broader strategic partnership, paving the way for the latest co-development initiative.

UNICORN, also known as NORA-50, was jointly developed by NEC Corporation, Sampa Kogyo K.K. and The Yokohama Rubber Co., Ltd. for Japan's Mogami-class frigates. Designed as an integrated mast, the system consolidates multiple communication, surveillance and electronic warfare antennas into a single structure, reducing the number of externally mounted antennas on a ship's superstructure.

The mast incorporates an omnidirectional surveillance radar antenna, electronic support measures (ESM) antennas, Wi-Fi and Link 16 antennas, UHF transmit and receive antennas, identification friend-or-foe (IFF) systems, VHF/UHF communication antennas, a tactical navigation system and a lightning conductor.

Apart from improving space utilisation and reducing maintenance complexity, the integrated design lowers a vessel's radar cross-section, enhancing stealth characteristics and making naval platforms more difficult to detect.

Development of the UNICORN system took place between 2015 and 2016, with serial production beginning in 2018. The mast was first installed on Japan's Mogami-class frigates in 2019.