China's Dongfeng -21 missiles are installed with over-the-horizon radar systems

Canada, "Han and defense," the article said, the PLA has a super-horizon radar system installed in the east -21 ballistic missiles, this aircraft carrier for the U.S. military created a huge threat. People's Liberation Army with Ultra-horizon radar ship target 3000 km away from detecting ability. As a counter, the U.S. Aegis missile defense system will be fully upgraded, or enhanced electronic warfare jamming capability, to ensure aircraft safety.

China's Dongfeng -21 missiles
  
According to the U.S. Global Strategic Network reported that the PLA has long been secretly developing a super-horizon radar technology (OTH) may have been a major breakthrough, with a detection target 3000 km away from the capacity of large ships. The article said that the PLA if the radar system installed in the east -21 ballistic missiles, the U.S. aircraft carrier will be a large threat, the U.S. military will take appropriate counter measures.
The article said that over the horizon radar (OTH), also known as-the-horizon radar, its most important advantage is not subject to restrictions on the curvature of Earth from the ionosphere (height 80 ~ 360km) to the ground (sea) surface height to detect all aircraft target of missiles and all vessels, with natural resistance to penetration, anti-stealth aircraft, anti-radiation missiles and so on.
Currently, the world's radar technology has advanced countries, such as the United States, Russia, Australia, Britain, France and Japan, has developed and deployed all OTH radar system. Qi mainly used for strategic early warning and remote tactical warning intelligence radar system in the most economic means to achieve the highest efficiency-consumption coefficient pairs Jingwai remote target of the early warning of soil air (sea) of the warning Shijiantigao Dao-hour orders of magnitude.
The article said that the West are most worried about the system is installed in the PLA's strategic missile Dongfeng -21 above, this will greatly improve the precision strike capability Dongfeng -21, a serious threat to the aircraft carrier cruising in the ocean. Dongfeng -21 maximum range of 1,800 kilometers, the PLA to conduct long-range precision strike weapons killer. The missile is divided into upper and lower levels, with solid fuel rockets that can carry 300,000 tons TNT equivalent of high-explosive warheads, in its own radar or imaging systems, guided by precision strikes on remote targets.
The outside world over the horizon radar technology developed by China have been concerned for a long time, various speculations, but has not been related to the fact that the exact message. U.S. Global Strategic Network article said that if the PLA does have ownership of the radar system, as a counter, the U.S. Navy Aegis missile defense system will be fully upgraded to ensure the safety of the aircraft carrier. In addition, the U.S. military will also consider enhanced electronic warfare jamming capability, target before the missile attack Dongfeng -21 to blindness.
 
However, some point of view, even if the equipment the PLA over the horizon radar system, to precision strike aircraft, it must grasp in advance the location of the aircraft carrier. Although this is not impossible, but the PLA now, still no easy task.
Over-the-horizon radar (OTH), known as the super-horizon radar early. It uses electromagnetic waves in the ionosphere and the ground between the reflection or diffraction of electromagnetic wave in the Earth's surface to detect targets. OTH radar generally work in the short-wave band, operating frequency of 3 ~ 30MHz. The most important advantage of this radar is not subject to restrictions on the curvature of Earth from the ionosphere (height 80 ~ 360km) to the ground (sea) surface to detect the air full height (aircraft, missiles), and sea targets (all ships). The radar distance (800 ~ 3500km), covering an area of large (single radar can reach 60 ° azimuth sector of 5.6 million square kilometers), with natural resistance to penetration, anti-stealth aircraft, anti-radiation missiles and so on. It is mainly used for strategic early warning and remote tactical intelligence warning radar system in the most economic means of achieving the most cost-effective long-range goals on the outside of early warning, so that the air-defense (sea) of the warning time to an order of an hour. Currently, the world's radar technology has advanced countries, such as the United States, Russia, Australia, Britain, France and Japan, has developed and deployed all OTH radar system.
OTH radar classification There are several ways: If the target signal by the scattering in the ionosphere form of-the-horizon backscatter radar can be divided over the horizon and forward scattering horizon. If the reflection of electromagnetic waves by ionospheric effects can be divided into-the-horizon radar horizon radar and ground wave OTH radar. Power through the ionosphere to reflection waves, and fold back to the ground, thus covering a large area, called the horizon radar; and diffraction effects through the Earth's surface so that wave propagation along the curve, called the ground wave as from the radar. As for the OTH radar coverage is relatively small role in a distance of only 200 ~ 400km, so except the former Soviet Union-the-horizon radar using sky wave - to wave a joint working outside the system, the other most of the post-horizon radar horizon backscatter radar (OTH-B).
Development necessity and feasibility of OTH radar
During the Cold War, the United States and the Soviet Union from starting their own homeland defense purposes, have active development OTH radar. Since the disintegration of the former Soviet Union, the original long-range bombers against the United States and significantly reduced the threat of intercontinental missiles, and the development and maintenance of-the-horizon radar is extremely expensive, so their deployment in recent years, the United States Department of Defense made a horizon system a series of adjustments: its eastern system has been almost in a "sleep" state, the western system and equipment in a few months after "keep running environment, to prevent damage to parts of the equipment, when they need immediate opening" of the "hot storage state", while others part of the system was abolished.
OTH radar in the U.S. Air Force in a "sleep" state, the U.S. Navy's ROTHR radar is limited by the military sector attention. The fundamental reason for this change is the main threat facing the United States changed fundamentally. Major threat to the United States from the unrest in South America and the Caribbean, the United States to safeguard its own security and interests, spent a lot of military spending in developing and maintaining systems for the Caribbean ROTHR.
The main function of OTH radar
3.1 The large coverage area
Radar coverage is far more than early warning aircraft. For example, the U.S. Navy built in Alaska ROTHR coverage up to 1.63 million square kilometers, including Japan and the Kamchatka Peninsula, the eastern Pacific near the Sea of Okhotsk. Covering an area equivalent to 1.1% of the Earth's surface, such a large coverage area, need to use the 12 E-3A (AWACS) early warning aircraft. Literature, covering the position angle of 120 °, the ground distance covered by the domain for the 1000 ~ 4000km of-the-horizon radar, it can cover a total area of 16 million square kilometers. Moreover, from sea to air can be full height detection.
3.2-altitude targets at sea and ship detection
Low-altitude radar intrusion is one of the four major threats. War, the enemy often used low-altitude penetration bombers and sea-skimming cruise missiles to attack. Radar can be found far away from them, thereby greatly increasing the warning time.
U.S. Air Force on-the-horizon radar cruise missile with great attention. January 1988 started a program, the use of improved AQM-34M (during the Vietnam War, an unmanned aircraft) to test-the-horizon radar detection of small targets. In the test, with this small plane in Puerto Rico and Bermuda over the ocean between the air 150 to 760 meters high for 48 simulated low-flying cruise missiles, the test was successful.
USAF East Coast Radar AN/FPS-118 verification process, the radar can not only discover 3335.4 km (1800 nautical miles) beyond cruise missiles, but also most of the time to track them. These cruise missiles RCS (radar cross section) is less than B-2 bomber, but higher than F-117A stealth fighter. The OTH radar can track the length of the Puerto Rican island of only 4.3m fly private aircraft.
OTH radar can detect distant ships. ROTHR test results show that the radar system in a specific region in the target detection and tracking capacity of more than the navy of the specified target, it successfully tracked a Mouyihaiyu of 25 ships in the 24, but also on the Ling one can barely follow.
3.3 against stealth aircraft
Stealth aircraft is to take plastic surgery techniques, the use of radar absorbing materials, and electronic warfare and other means to get the stealth effect, which is another major threat to modern radar. However, over-the-horizon radar has the potential to counter stealth aircraft. As the high-frequency radar horizon, it's a wavelength of 10 ~ 60m, the wavelength dimension with the most aircraft the size of the main structure or close to or even longer. According to electromagnetic wave scattering theory and the experimental results show: At this point the shape and details of the target radar cross section (RCS) of not only related with the irradiated area. Thus, the effect of plastic stealth would be much lower. In addition, the current microwave absorbing material is only applicable to the scope of the FM invalid. Especially since the top-down-the-horizon radar wave radiation target, so stealth is still large RCS targets. For example, B-2 bombers in the head direction of the RCS may be less than 0.1m2, light from above or below, its RCS up to a few square meters.
3.4 sea air traffic control and communications
OTH radar at sea and air traffic control and communications, even in enemy identification, rescue and other organizations, has broad prospects. Especially with ships at sea has long been a reliable communications difficult problem. If you use the-horizon radar, and aircraft and ships have side upload transponders, will be able to communicate through coded signals and identify the enemy. Also, upload the aircraft altimeter, a high degree of data sent back over the horizon radar receiver can not make up-the-horizon radar altimeter problem.
U.S. East Coast-the-horizon radar in January 1990 on a distress signal distress responded. At that time, an aircraft pilot reported, 4 in 3 sets of jet engine failure occurred and requested an emergency landing in Canada navigate. But Canada's Gander Marine air traffic controller can not do anything over the North Atlantic have been unable to locate the route had been damaged, over-the-horizon radar, air traffic controllers to Canada informed the measured location of the aircraft, controllers according to navigate to the Gander flight emergency landing.
3.5 surveillance aircraft, maritime drug smuggling suspect and led the side planes have been intercepted
OTH radar except for strategic early warning, the U.S. Air Force and put it in the application extended to monitor drug transport such as aircraft. U.S. Air Force program executive officer Eric B · C3 Major General Nelson said: "The radar can track aircraft over the Atlantic, to provide intelligence-gathering purposes, can be observed in the southern coast and found a small low-flying aircraft, was a clear advantage." Built in Alaska ROTHR identified in the final stages of Virginia, that is, 4 May 1989 during the track a few planes flying out of the small plane from Colombia, they may be involved in illegal drug trafficking. On one occasion, ROTHR to obtain tracking data to E-2C early warning aircraft, E-2C to guide the jet to intercept the U.S. Coast Guard. So, this twin-engine plane was forced down in Bimini drug (Bimini), the plane of the drug smugglers were apprehended.
3.6 Remote Ocean state
Radar can measure sea surface wind and ocean current conditions, can real-time tracking the movement of the typhoon. Test showed that the determination of ultra-horizon radar, typhoon winds and buoy directly measured results agree well. In addition, the waves can be measured with the Doppler spectrum of the cycle, height and direction. And measured value, less than 10% errors, so over-the-horizon radar surveillance in a large range of sea conditions, can monitor a wide range of sea conditions, weather forecasting, navigation safety to contribute.
3.7 deal with the threat of anti-radiation missile
ARM is an important survival of the enemy radar, conventional radar designers are finding ways to tackle this important threat to the possible measures. In dealing with anti-radiation missiles, Radar is a unique advantage. As the anti-radiation missile diameter is small, the antenna can not do much, and therefore can only attack for more than 1GHz frequency radar, but on-the-horizon radar can not attack, so that the viability of-the-horizon radar has been greatly improved .

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