Last time on Hardware Monday, we looked at the J/FPS-5, Japan’s most advanced radar installation and a key part of its ballistic missile defense system. This time, we will look at the radar network more broadly.

Extent of Radar Network

The computerised network, known as JADGE (Japan Aerospace Defense Ground Environment), is operated and maintained by the ASDF. It was originally developed in the early 1960s from the handover of USAF stations, and some of the equipment dates back to these origins (e.g. AN/FPS-20), and became operational in 1989. Generally located on coastal mountain tops, the radar systems afford the ASDF full coverage of the Japanese islands.

Coverage of Japan's Radar Network

Coverage of Japan's Radar Network (Click image for bigger version)

The above map was recreated and adapted from a book by Toshiyuki Shikata, retired GSDF Lt. General, Professor at Teikyo University and security advisor to the Governor of Tokyo, Shintaro Ishihara – a clear authority on Japanese military issues. It shows the location of ASDF sub-bases with radar installations, and their overlapping coverage at 50, 75, 130 and 200 nautical miles (note the map in the book, and the one above, is simply an approximation). What is clear is that at 200NM, Japan is fully covered by its air defense radars, although the full range of the newer installations, and limitations of the older ones are not included (they are presumably kept secret for national security).

The early-warning installations provided by JADGE also support electronic and electro-magnetic measurement intelligence (ELINT/ESM) collection stations – near Wakkanai, Nemuro, Okushiri, Seburijima, Fukuejima, Misawa and Miyakojima. There are reports of communications intelligence (COMINT) collection stations near Takaoyama, Fukuejima and Miyakojima.

Composition of Radar Network

The 28 integrated facilities around Japan that comprise JADGE are coordinated via the US-developed Link 16 Joint Tactical Information Distribution System (JTIDS)/Multifunctional Information Distribution System (MIDS) at ASDF Air Defense Command, currently being transferred to Yokota AFB from Fuchu Air Station.

The ASDF operates seven J/FPS-2 static three-dimensional radars, first installed in 1979 with a range of 200 km (approx. 100 nautical miles).

A further seven facilities operate the recently upgraded J/FPS-3A, a three-dimensional phased array radar with a search range of around 370 km (approx. 200 nautical miles) and height-finding at 150 km (approx. 80 nautical miles).

The most modern additions to the network are the six J/FPS-4 sites and the five J/FPS-5 sites, while older AN/FPS-20 and AN/FPS-6 radars operate at four sites (one per Air Defense Force).

Below is a break down of the types of radars at each installation, as gleaned from the Japanese ‘Radar Site’ page over at Wikipedia.

ASDF Northern Air Defense Force
Northern Aircraft Control and Warning (AC&W) Wing
Unit/Location Emblem Type
18th AC&W Sq.
Wakkanai Sub-base
18th Aircraft Control and Warning Squadron Emblem J/FPS-2
28th AC&W Sq.
Abashiri Sub-base
28th Aircraft Control and Warning Squadron Emblem J/FPS-4
26th AC&W Sq.
Nemuro Sub-base
26th Aircraft Control and Warning Squadron Emblem J/FPS-2
45th AC&W Group.
Tobetsu Sub-base
45th Aircraft Control and Warning Group Emblem J/FPS-3A
36th AC&W Sq.
Emori Sub-base
36th Aircraft Control and Warning Squadron Emblem AN/FPS-20
AN/FPS-6
42nd AC&W Group
Ominato Sub-base
42nd Aircraft Control and Warning Group Emblem J/FPS-5
37th AC&W Sq.
Yamada Sub-base
37th Aircraft Control and Warning Squadron Emblem J/FPS-2
33rd AC&W Sq.
Kamo Sub-base
33rd Aircraft Control and Warning Squadron Emblem J/FPS-3A
29th AC&W Sq.
Okushirijima Sub-base
29th Aircraft Control and Warning Squadron Emblem J/FPS-4
ASDF Central Air Defense Force
Central Aircraft Control and Warning (AC&W) Wing
Unit/Location Emblem Type
27th AC&W Group
Otakineyama Sub-base
[N/A] J/FPS-3A
46th AC&W Sq.
Sado Sub-base
46th Aircraft Control and Warning Squadron Emblem J/FPS-5
44th AC&W Sq.
Mineokayama Sub-base
44th Aircraft Control and Warning Squadron Emblem J/FPS-4
23rd AC&W Group
Wajima Sub-base
[N/A] J/FPS-3A
22nd AC&W Sq.
Omaezaki Sub-base
[N/A] J/FPS-2
35th AC&W Sq.
Kyogamisaki Sub-base
35th Aircraft Control and Warning Squadron Emblem J/FPS-3A
1st AC&W Group
Kasatoriyama Sub-base
1st Aircraft Control and Warning Group Emblem J/FPS-3A
5th AC&W Sq.
Kushimoto Sub-base
[N/A] AN/FPS-20
AN/FPS-6
ASDF Western Air Defense Force
Western Aircraft Control and Warning (AC&W) Wing
Unit/Location Emblem Type
7th AC&W Sq.
Takaoyama Sub-base
7th Aircraft Control and Warning Squadron Emblem J/FPS-4
17th AC&W Sq.
Mishima Sub-base
17th Aircraft Control and Warning Squadron Emblem J/FPS-2
19th AC&W Sq.
Unijima Sub-base
19th Aircraft Control and Warning Squadron Emblem J/FPS-2
43rd AC&W Group
Seburiyama Sub-base
43rd Aircraft Control and Warning Group Emblem J/FPS-3A
15th AC&W Sq.
Fukuejima Sub-base
15th Aircraft Control and Warning Squadron Emblem J/FPS-4
9th AC&W Sq.
Shimokoshikijima Sub-base
9th Aircraft Control and Warning Squadron Emblem J/FPS-5
13th AC&W Group
Takahatayama Sub-base
13th Aircraft Control and Warning Group Emblem AN/FPS-20
AN/FPS-6
ASDF Southwestern Composite Air Defense Division
Southwestern Composite Aircraft Control and Warning (AC&W) Wing
Unit/Location Emblem Type
7th AC&W Sq.
Takaoyama Sub-base
7th Aircraft Control and Warning Squadron Emblem J/FPS-4
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A former contributor to World Intelligence (Japan Military Review), James Simpson joined Japan Security Watch in 2011, migrating with his blog Defending Japan. He has a Masters in Security Studies from Aberystwyth University and is currently living in Kawasaki, Japan. His primary interests include the so-called 'normalization' of Japanese security (i.e. militarization), and the political impact of the abduction issue with North Korea.
James Simpson has 254 post(s) on Japan Security Watch