Tokyo commits to ballistic missile defence capability

In late December 2017, the government of Japan announced that it will proceed with the procurement of a pair of so-called AEGIS Ashore Anti-Ballistic Missile (ABM) Surface-to-Air Missile (SAM) systems to be deployed to protect the country against ballistic missile attack by the Democratic People’s Republic of Korea.

The government stated that the locations of the two systems have yet to be determined, although it did disclose that the procurement could take place at 2023 at the earliest and cost around $880 million. The AEGIS Ashore sites are expected to be equipped with Raytheon RIM-161 SM-3 Block-IIA SAMs.

The deployment of the AEGIS Ashore system could see the country acquiring the Lockheed Martin AN/SPY-1D radar to equip both sites as part of the ensemble to provide both the detection of any incoming missile, and guidance for the RIM-161 SM-3 Block-IIA SAMs.

Publicly available documentation published by the Union of Concerned Scientists states that the AN/SPY-1D transmits in S-band with a frequency waveband of 3.1 gigahertz (GHz) to 3.5GHz, with a 400 megahertz (MHz) wideband waveform divided into ten 40MHz bandwidths allowing frequency hoping across this 400MHz band. The documentation continues that the radar could have sufficient range to track a target with a similar size to an incoming ballistic missile’s final booster stage at a range of up to 400 nautical miles/nm (740km) or an incoming ballistic missile warhead at a range of 167nm (310 kilometres). The acquisition costs for the radar could amount to $61.4 million for the two radars, based on publicly available unit costs for the AN/SPY-1D.

For more information on AEGIS Ashore and the Japanese Defence Mininster’s thoughts on this, please see here. 

Thomas Withington