The Japanese SAM Network

INTRODUCTION

Japan is a heavily populated nation spread out over a series of islands in the Western Pacific. American and Japanese SAM systems have protected Japanese airspace since the early days of the Cold War. Aging systems and recent developments in the region have led Japan to begin fielding a modern air defense and anti-missile network.

OVERVIEW

Japanese SAM systems are subordinate to both the JGSDF and the JASDF. The JGSDF operates the HAWK and Chu-SAM systems, with Japanese Patriot batteries being operated by the JASDF. However, JASDF control networks provide targeting and EW support for all SAM systems in Japan, as the JASDF operates the Aircraft Control and Warning Wings manning Japan's EW sites. 5 JGSDF units and six JASDF units are equipped with HAWK or Patriot SAMs.

EW

24 active and one inactive EW site form the basis of Japan's early warning network. These sites are located around the periphery of Japan and provide support for both JASDF and JGSDF SAM units. The bulk of these locations operate the indigenous FPS-3 EW radar.

The locations of Japan's EW sites can be seen in the image below:
PATRIOT

In 1984 Japan chose the Patriot missile system to replace its aging Nike-Hercules batteries. The initial PAC-1 batteries were upgraded to PAC-2 standard. Six missile groups operate the Patriot in the JASDF, oriented throughout the nation. These batteries are primarily located on the grounds of former Nike-Hercules units, taking advantage of the hardened revetments already present to protect the TELs.

A representative Patriot battery can be seen in the image below. This site is located near Tokyo, and is a former Nike missile position. The main upgrade performed to Nike sites allowing Patriot operation is the inclusion of a raised berm for the AN/MPQ-53 engagement radar, which can clearly be seen. Amusingly, two of the site's former occupants remain as gate guards.
The locations and coverage zones of Japan's Patriot batteries can be seen in the image below. A portion of the Patriot batteries located on Okinawa are in fact operated by the US Army, but cannot sufficiently be differentiated based on the imagery available. As such, they are all included here.
HAWK AND CHU-SAM

The JGSDF has operated the HAWK missile system since 1965. Eleven batteries appear to remain active in available imagery, with other batteries held in-garrison at various locations.

The locations and coverage zones of Japan's active HAWK batteries can be seen in the image below:
Chu-SAM, the Mitsubishi Type 03, is Japan's indigenous replacement for the HAWK in JSGDF service. Chu-SAM was inducted in 2005, with the first training firings taking place at Fort Bliss, Texas in late 2006. The extent of Chu-SAM deployment is not currently known. Chu-SAM will offer a significant capability increase in terms of performance and mobility when compared to the HAWK.

Chu-SAM components can be seen in-garrison near Tokyo in the image below:
MISSILE DEFENSE

The increasing threat of DPRK ballistic missiles has led Japan to pursue a relatively robust BMD network. There are three primary components to the system: sensors, land-based PAC-3 missiles, and sea-based SM-3 missiles. The system began to be studied in 1995, with the first component, the PAC-3, becoming operational in 2007. PAC-3 systems were deployed to northern Japan in 2009 in anticipation of DPRK missile tests.

The BMD sensor network will consist of three radar types. Seven FPS-3 radars in the existing EW network have been modified to improve missile detection capabilities. In addition, four new FPS-5 phased-array radars (previously developed as the FPS-XX) will be built by 2012. In the interim, a US FBX-T radar system deployed to Japan in June of 2006 to provide BMEW capability. This system was deployed at Shariki in northern Japan. The US also began operating PAC-3 missiles at Kadena in late 2006.

Japan's projected land-based BMEW network can be seen in the image below. Modified FPS-3 sites are marked with light blue circles, FPS-5 radar site locations are marked with dark blue circles, and the FBX-T radar location is marked as a yellow circle.
The FBX-T radar system can be seen in the image below. This radar has been used to monitor DPRK missile tests. This is a temporary location, with a more permanent site being constructed approximately 1 kilometer to the south.
For the sea-based portion of the network, four Kongo-class AEGIS destroyers will be upgraded and equipped to fire the SM-3. Work on these four vessels, the Kongo, Chokai, Myoko, and Kirishima, will be complete by the end of 2010. Kongo completed modifications in 2007 and conducted Japan's first AEGIS missile intercept in December of that year.

Modification of Japan's command and control networks to incorporate the new BMD capabilities and mission will be completed by 2012

CONCLUSION

The changing threat environment, coupled with the age of legacy systems such as the HAWK, have led Japan to develop one of the most modern air defense networks found in the world. When the BMD network is fully operational after 2012, Japan will have provided its citizens with a robust defensive capability to repel both air and missile attacks on its soil.

SOURCES

-Satellite imagery provided courtesy of Google Earth

PAC-3 deployed
PAC-3 flight test
Chu-SAM
Chu-SAM testing

Japan's Missile Defense, March 2007
Overview of Japan's Defense Policy, Japanese MoD
Defense White Paper, Japanese MoD, 2009