Unlike a number of European countries, after the end of the Cold War, Japan has not lost its positions in terms of preserving the radar field over the entire territory of the country and adjacent sea areas. Moreover, new radar stations are regularly built, and the existing ones are being modernized and undergoing major repairs.
Japan's modern air defense control system
The entire territory of Japan is divided into four air defense zones. The central command post is located at Yokota airbase, the headquarters of the Northern Air Defense Forces is at the Misawa airbase, the headquarters of the Central Air Defense Forces is at the Iruma airbase, the headquarters of the Western Air Defense Forces is at the Kasuga base, the headquarters of the Southwest Air Defense Forces is at the Naha airbase.
The headquarters of the 5th US Air Force is also located on the territory of Yokota airbase. In real time, the parties exchange data received from the air monitoring posts and actively cooperate in the event of a crisis.
The Japanese air defense system is controlled by a new generation high-performance automated control system JADGE (Japan Aerospace Defense Ground Environment), which was launched in 2009.
Compared to the decommissioned BADGE Kai ACS, the new JADGE combat control system is capable of processing many times large amounts of information and responding more quickly to emerging threats. In addition to aerodynamic targets, the system is capable of working with ballistic missiles and directing existing missile defense systems at them. The Japanese media have repeatedly published statements that the communication and information components of Japan's air defense are the best in the world. However, no details were provided to reveal the actual characteristics of the system.
It is known that the JADGE ACS, in standby mode, automatically processes information about the course of all aircraft flying in and around Japan's airspace, tracks approaching aircraft of unknown nationality, makes a request and directs interceptor fighters at them. All actions are maximally visualized and documented on several independent media.
When ballistic targets are detected, their trajectory is calculated, with the determination of the predicted place of impact. In the event of a threat to objects located on Japanese territory, target designation is issued to the existing ground-based air defense / missile defense systems: Patriot PAC-3, Type 03 (Chu-SAM), as well as naval SM-3 Block IB and SM-3 Block IIA.
Detection means (ground-based radar posts, AWACS aircraft, airborne radars of fighters, radars of warships) and means of fire destruction (anti-aircraft and anti-missile systems of land and sea-based, fighter-interceptors) are linked into a single information network of the JADGE ACS. Through external channels, information is received from American AWACS aircraft based in Japan, and from American AN / FPS-117 ground radars deployed at Kadena airbase.
Tactical Data Exchange System (TDS) provides real-time communication between the main elements connected to the JADGE system.
In peacetime, fiber-optic lines, high-frequency radio relay equipment and HF / VHF radio networks are used to transfer information between ground points.In case of suppression and failure of traditional communication means, it is supposed to use satellite channels and mobile multichannel communication terminals J / TRQ-504 and J / TRQ-506.
In the opinion of the Japanese leadership, in the light of the existing territorial disputes with neighbors and the aggravation of the international situation, the control system of Japan's air defense forces needs to be improved. So, according to Japanese data, in 2008, 31 Chinese aircraft and 193 Russian aircraft approached the air borders of Japan. In 2018, this figure increased to 638 Chinese and 343 Russian aircraft.
Modern Japanese radar airspace control
Currently, all Japanese airspace and surrounding areas are monitored by radars at high and medium altitudes to a depth of 400 km. In total, there are 28 permanent radar posts.
Until recently, the most numerous stationary radars deployed in Japan were the J / FPS-2 / 2A (three-dimensional radars of this type, commissioned in 1982, were considered in the publication Japan's Air Defense System during the Cold War). Currently, six such stations remain in service, and in the next 2-3 years they will be replaced with new generation radars.
In March 1992, in Kyoto prefecture, near Cape Kyogamisaki, on the site where the American AN / FPS-20В and AN / FPS-6 radars were previously located, the first stationary three-coordinate radar with AFAR J / FPS-3 was built. After debugging work, the station was commissioned at the end of 1992. According to information available in the public domain, the detection range of air targets flying at high altitude exceeded 450 km. The station, located 451 m from sea level, could see low-altitude targets at a distance of 70 km.
Already in the 1960s, the Japanese came to the conclusion that, taking into account the local climate, it was necessary to protect the antenna devices of the radars with plastic radio-transparent fairings. It turned out to be more profitable to invest in the construction of protective structures than to regularly repair the elements of stations that are exposed to the destructive effects of unfavorable meteorological factors.
Trial operation of the J / FPS-3 radar at Cape Kyogamisaki continued until 1995. After making a number of improvements to the design, Mitsubishi Electric built 6 more such stations by 1999.
By 2009, all available radars were brought to the level of J / FPS-3 Kai, after which operational reliability improved and the ability to sustainably detect and track ballistic missiles appeared. The station, known as the J / FPS-3ME, is the latest modification.
The J / FPS-4 three-axis radar, developed by Toshiba, was intended to finally replace the J / FPS-20S radar rangefinders and J / FPS-6S altimeters, which were built in Japan under an American license. The detection range of high-altitude targets is up to 400 km.
At the design stage of the J / FPS-4 radar, while maintaining the characteristics of detecting air targets at the level of a radar complex consisting of J / FPS-20S and J / FPS-6S, the new station was required to reduce operating costs and increase the operating time by several times. refusal. For this, a significant part of the electronic units was redundant, with the possibility of their remote switching.
Like other stationary Japanese airspace control radars, the elements of the J / FPS-4 station were located on a concrete base, and the antenna post was covered with a radio-transparent dome.
Thanks to the use of technical solutions, components and element base, widely used in serial products manufactured by Toshiba, the purchase cost of the J / FPS-4 equipment set has become much cheaper compared to J / FPS-3. From the very beginning, measures were considered to reduce the sensitivity of the station to organized interference and active simulators of the radar operation were developed, designed to distract anti-radar missiles.
The first station, located on Mount Takao, in Shimane Prefecture, began trial operation in 2002. Already in January 2003, experts came to the conclusion that the J / FPS-4 radar meets the requirements and is suitable for adoption. After that, in the period from 2006 to 2008, 5 more such radars were built in different parts of Japan. Three stations were delivered in an improved version of the J / FPS-4A.
Air defense experts have noted in the past that the Japanese Air Self-Defense Forces have had very limited use of mobile radars and relied heavily on powerful radar systems stationed in fixed positions. This approach reduced operating costs and made the radar network less weather-dependent. However, given that the coordinates of all Japanese stationary radar posts are well known, they can be quickly destroyed by air attack.
In this regard, in the early 1980s, NEC was awarded a contract to develop a mobile radar. The antenna post of the J / TPS-102 three-coordinate station outwardly resembles the antenna of the J / FPS-1 stationary radar. All elements of the radar complex are located on the Type 73 cargo chassis.
The radar uses a cylindrical AFAR that does not require mechanical rotation. A second omnidirectional antenna (a small cylinder on the roof of a large cylinder) is used to suppress spurious signals. Radar J / TPS-102 operates in the frequency range 1.5-2 GHz. The detection range of the F-4ЕJ fighter flying at an altitude of 8000 m is 370 km. The maximum detection range for large high-altitude targets is about 500 km.
The J / TPS-102 radar was put into service in 1992, deliveries of the stations were carried out until 2000. Currently, the Air Self-Defense Force has 7 J / TPS-102 radars, but they are not on constant duty and are considered as a supplement and a mobile reserve in crisis situations, in case of failure of stationary radar posts.
J / TPS-102 mobile radars are distributed between the regional command posts of the Japanese air defense system, where they are periodically deployed.
It is reported that on the westernmost island of the Japanese archipelago Yonaguni is planned to build a modernized stationary radar J / TPS-102A.
Modern Japanese AWACS aircraft
Currently, the Air Self-Defense Forces continue to actively operate the E-2C Hawkeye AWACS aircraft, acquired in the 1980s. These vehicles are assigned to the Air Surveillance Group of 601 Squadron (Misawa Air Base, Aomori Prefecture) and 603 Squadron (Naha Air Base, Okinawa Island).
In order to extend the service life, all Japanese E-2C aircraft underwent refurbishment and modernization at the Kawasaki Heavy Industries facility in the city of Gifu. According to information published in the Japanese media, some of the aircraft have been brought to the level of E-2C Hawkeye 2000.
In 2014, the Air Self-Defense Forces command announced a desire to replace the worn-out E-2C Hawkeye AWACS aircraft with new E-2D Advanced Hawkeye. The first E-2D was delivered to Japan in March 2019. The Air Defense Forces currently have three E-2D aircraft. In total, Japan has ordered nine E-2D Advanced Hawkeyes worth $ 3.14 billion. It is stated that these AWACS aircraft will interact with the recently received F-35A fighters.
E-2D is by far the most advanced modification in the Hawkeye AWACS aircraft family. In addition to the new communication, navigation and data display and processing equipment, the most notable innovation was the installation of the AN / APY-9 radar with AFAR. According to officially unconfirmed information, this station is capable of detecting high-altitude aerial targets at a distance of more than 600 km, due to its high energy potential, and effectively control flights of aircraft made using low radar signature technology.
It is noted that the existing Japanese AWACS aircraft, upgraded to the E-2C Hawkeye 2000 level, fully met the requirements, and the acquisition of the E-2D Advanced Hawkeye is primarily associated with the appearance of the 5th generation fighters in Russia and China.
In early 1991, the Japanese government announced its intention to acquire heavy AWACS E-3 Sentry aircraft. But due to the fact that by that time the production of the base Boeing 707 had already been discontinued, it was decided to build a flying radar picket for Japan on the basis of a new generation Boeing 767-200ER passenger aircraft. When creating a new AWACS aircraft, the equipment of the latest versions of the E-3 Sentry was used.
Created by order of Japan, the E-767 AWACS is more consistent with modern realities and has significant modernization potential. In general, the characteristics of the radar and radio systems of the Japanese aircraft are similar to those of the E-3C aircraft.
At the same time, the Japanese E-767 is a faster and more modern aircraft with a cabin twice the volume, which makes it possible to rationally accommodate the crew and equipment. Most of the electronics are installed at the front of the aircraft, and the radar dish is closer to the tail end.
Compared to the E-3 Sentry, the E-767 has more free space, potentially allowing additional hardware to be installed. In order to protect the crew from high-frequency radiation, the windows along the side of the aircraft have been eliminated. On the upper part of the fuselage, there are numerous antennas of radio engineering systems. Despite the large internal volumes, the number of operators, thanks to the use of automated workstations and high-performance computers, has been reduced to 10 people. Information received from the radar and the passive radio intelligence station is displayed on 14 monitors.
Japan paid approximately $ 3 billion for the four E-767s. An additional $ 108 million was spent in 2007 on improved radars and new software.
The basis of the radar system of the Japanese aircraft AWACS E-767 is the pulse-Doppler radar AN / APY-2, combined with the 4PiCC-2 onboard computer. This station is capable of seeing low-flying small-sized targets at a distance of up to 400 km, targets flying in excess of up to 650 km. The upgraded radar can detect objects with a RCS of 1 m² at a range of up to 425 km. At the same time, stable tracking of up to 100 targets at the same time is provided.
The first E-767 aircraft, fully equipped with the necessary equipment, was handed over to the Air Self-Defense Forces in April 1998. The achievement of the operational readiness of this aircraft was announced in January 2000.
Currently, four E-767 aircraft available in Japan are brought together in the 602nd radar patrol squadron of the Radar Warning and Flight Control Corps, whose headquarters is located at Hamamatsu airbase.
Approximately every 5-6 years, E-767 AWACS aircraft are undergoing repair and modernization at the Kawasaki Heavy Industries facility in Gifu. Toshiba is responsible for updating the electronic filling.
By 2011, all E-767 aircraft were equipped with Joint Tactical Information Distribution System (JTIDS) equipment operating in the Link 16 data transmission format.
In 2013, the Japanese government allocated $ 950 million to upgrade the on-board computer complex, state recognition systems, and cryptographic protection of information transmission channels. Also, new navigation and electronic warfare equipment was installed.
Improvement of avionics, maintaining the airframe and general on-board systems of the E-767 in good technical condition allows achieving a high degree of combat readiness and operating the existing AWACS aircraft for another 15 years. As of 2020, two E-767 aircraft were constantly in operational readiness for departure: one was on patrol, and another was undergoing maintenance.