Anti-reconnaissance countermeasures and anti-naval electronic warfare cover naval radar electronic warfare, communication electronic warfare,

Underwater acoustic electronic warfare, photoelectric electronic warfare and naval remote control, telemetry and navigation electronic warfare. Among them, the ground of naval radar electronic warfare

Bit is particularly important. This is determined by the characteristics that modern naval warfare is dominated by missile warfare. Main contents of naval radar electronic warfare

It is the reconnaissance and anti-reconnaissance of naval radar, and it is confrontation and opposition.

Naval radar reconnaissance

Radar reconnaissance is an electronic reconnaissance. The task of naval radar reconnaissance is to use the electronic support measures of naval ships and carrier aircraft.

Various radar reconnaissance receivers and other facilities usually detect electromagnetic radiation signals that threaten radar at sea to find out their skills.

Technical parameters such as radar frequency and azimuth provide tactical basis for taking countermeasures and implementing interference in wartime; During the war, it assisted satellites.

As well as airborne electronic support measures and equipment, conduct panoramic surveillance of the sea and air, and find out the types, quantities and configurations of various electronic equipment of the enemy.

Setting, deployment and its changes, alarm through threat identification, and guide ship-borne anti-radiation missiles into enemy radar (even

Use its aircraft carrier or aircraft to carry out a devastating blow. The above tasks face more and more challenges in the following aspects:

(1) Modern electromagnetic environment is extremely complex and dense. For example, in the Gulf War, the US military used electronic warfare in the theater.

The electromagnetic signal test shows that the signal environmental density is as high as 654.38+200,000 ~ 654.38+500,000 pulses per second. In addition, electromagnetic radiation is usually used.

Among these signals, radar signals are mixed with communication signals and various other electrical signals.

(2) Contemporary naval operations mainly take place in the offshore environment, which is a high clutter environment. Electromagnetic signals emitted offshore

It includes not only signals from friendly forces or neutral countries, but also all kinds of civilian use from the ground, sea and air.

Signals and military signals.

(3) Enhance the electronic anti-reconnaissance and anti-jamming characteristics of enemy radar from the system and technology.

It increases the complexity and difficulty of naval radar reconnaissance.

(4) When the weather and propagation conditions in the war zone are bad or there is enemy electronic interference, naval radar reconnaissance will become more and more.

For difficulties. ? Therefore, the naval radar reconnaissance receiver must have high sensitivity, high interception probability and strong sorting.

The ability to analyze and identify real threat signals and judge their types and threat levels; In addition, according to its number

Quantity, work and distribution, etc. , determine the nature of the target and action attempt, and decide the measures we should take.

At present, the advanced naval radar reconnaissance receiver in the world has an interception probability as high as 100% and an interception frequency range of.

The composite signal modulates electromagnetic waves between 0.5 and 40 GHz. Its air interception distance is greater than the radar detection distance.

The interception distance at sea is greater than the line of sight, and the fastest signal interception time is tens of nanoseconds.

Naval radar countermeasure

Naval radar countermeasure refers to the receiving system, display system and automatic control of enemy naval radar by active and passive means.

The tracking system implements electronic interference. It includes active interference, passive interference and compound interference. Active intervention? Active jamming technology

It uses jammer to emit jamming signal with certain waveform to jam and deceive enemy radar. Active interference is generally divided into noise interference.

And deceptive interference.

Noise interference is also called suppression interference. It covers or engulfs the enemy's radar screen by emitting high-power noise signals.

The target echo on the plane made the enemy radar unable to work.

Deception jamming is to deceive the enemy with jamming signals. Deceptive jamming allows enemy radar to see the target, but makes it unusable.

Accurate information of the target can be obtained, but only distortion parameters such as distance, azimuth and speed can be obtained. Displayed on enemy radar screen

This is a false echo similar to the real target.

The naval radar jammer with active jamming can cover the electromagnetic frequency domain below 20 GHz at present, and its response time is

1 ~ 2 seconds, and the power of clutter interference can reach megawatt level. The most advanced jammer can jam 80 targets at the same time.

passive jamming

As the name implies, passive interference is a kind of interference in which the interfering body itself does not radiate electromagnetic energy. Common Passive Jamming to Radar

There are two main interference methods:

(1) Launching or dropping all kinds of chaffs and reflectors made of materials that can reflect electromagnetic waves will interfere with enemy radar.

Excuse me. For example, a single chaff bomb can form an airborne interference cloud of 1000 ~ 3000 square meters within 3 ~ 5 seconds after its explosion, and

It can be suspended for 10 minute to cover up the real target that the enemy radar wants to capture (that is, our ship or carrier-based aircraft) or lure the enemy.

Radar tracks false targets (that is, jamming clouds).

(2) The stealth design of the ship (or carrier aircraft) is adopted, and the surface of the ship (or aircraft body) is coated with electromagnetic wave absorbing materials.

Materials and other stealth methods, in order to weaken the reflection of the target to electromagnetic waves, making it difficult for enemy radar to find the target. For example, the law

China "Galeries Lafayette" class frigate adopts streamlined shape design, the outer wall of the superstructure is inclined 10, and it is painted with wave-absorbing paint.

A series of stealth measures, such as painting the hull, have reduced the radar reflection area of this class of ships by 60% compared with the traditional design, and achieved good results.

Stealth effect.

combination interference

Combined interference is to combine all kinds of interference mentioned above in many ways. Several active interferences can not only be combined properly, but also be active.

Interference and passive interference can also be combined to give full play to the best interference effect. For example, AN/ALQ99D in the United States and

The effective power of AN/ALQ99E jammer reaches 10 kw in 30 MHz ~ 18 GHz frequency domain and 200 ~

All marine radars such as early warning, height measurement, guidance, monitoring, gun aiming and guidance within 300 kilometers; They are related to

AN/ALE43 carrier aircraft chaff cutting spreader, AN/ALE40 chaff and tracer launcher are passive devices with excellent performance.

The cooperation of jamming equipment achieved good results in the Gulf War. ? Naval radar anti-reconnaissance mission

It is to prevent our radar signal from being intercepted or difficult to identify by the enemy reconnaissance receiver, and even if it is identified by the enemy, it is not easy to identify.

Roger that. ? The methods of naval radar anti-reconnaissance mainly include:

(1) The main radar is hidden at ordinary times and only used in wartime, so as to shorten the start-up time of the shipborne radar as much as possible.

(2) The radar signal design should adopt pseudo-noise signals that are not easily recognized by enemy reconnaissance receivers, including pulse frequency modulation signals.

Signal, pulse pseudo-random coded signal and pseudo-random repetition frequency signal, etc.

(3) Adopting the technology of low interception probability. This technology can narrow the scope of the enemy reconnaissance receiver and the role of our radar.

The ratio of distance (that is, interception probability) makes it impossible for enemy reconnaissance receivers to intercept targets outside our radar range.

Our radar signal. For example, the Dutch navigation and maritime search radar is such a low interception probability radar. radar

Using FM continuous wave transmission mode, although its output power is only 1 MW ~ 1 W, its range is the same as that of conventional radar.

Almost the same, and has the excellent characteristics of "silence" or "concealment", and the interception probability is low.

(4) Adopt frequency agility method. Using random fast frequency hopping is an important and effective means of radar anti-reconnaissance. at present

The number of pulses required for frequency aiming of jammer is decreasing. By the early 1990s, the performance level of jammer had been improved to 1 ~ 3.

Frequency guidance can be completed in one pulse. But as long as the radar frequency hopping speed is fast enough (such as pulse frequency hopping), the frequency hopping range is enough.

Wide enough, it is difficult for jammers to find and track radar.

(5) Using bistatic or multistatic working system or passive positioning mode. When a bistatic or multistatic work system is adopted,

Because our radar transmitting and receiving bases are located in two places, the enemy reconnaissance receiver can only intercept and track the radar launched by our country.

The signal from the shooting station can't be detected, let alone interfere with the radar receiving station on the ship. If we activate the radar,

If the station is set in a satellite or a carrier-based aircraft flying in the air or a closely guarded rear naval base, it will undoubtedly greatly enhance our radar.

Anti-reconnaissance and anti-jamming capability of launch pad. Passive location method is to induce enemy targets to start jammers or interests.

Using the electromagnetic signal radiated by the target itself to determine the parameters of the target to prevent our radar from being detected.

Naval radar countermeasure resistance

Radar anti-jamming is radar anti-jamming. Its technical measures are divided into two categories: one is when the enemy interferes with our radar connection.

Try to eliminate, weaken and improve the useful signal level before shutdown; The other is when enemy interference enters our radar.

After receiving the machine, the interference signal and the useful signal are distinguished by their differences in waveform, spectrum and other structures, so as to suppress the interference.

Jamming and the purpose of extracting enemy target information from jamming background. ? The countermeasures of naval radar mainly include:

(1) power supply countermeasures. The simplest way to improve the anti-jamming ability of radar is to increase the emission energy as much as possible. At the peak of work

Under the condition of a certain rate, in order to obtain a higher average transmission power, it is necessary to adopt the method of pulse compression, that is, to transmit a wide pulse signal.

After receiving and processing the echo, No.1 outputs a narrow pulse signal. This increases the radar range and improves the radar.

Resolution.

This method is anti-deceptive to some extent. Shipborne EMPAR phased array radar being developed in Italy. Active interference energy

Force.

(2) Monopulse angle tracking. Monopulse radar can determine that it is detected according to the information extracted from the echo of a single pulse.

Because of the angular position of the signal source, many radar countermeasures used to interfere with beam sequential scanning radar are almost completely lost.

Effective.

(3) Pulse repetition frequency agility. This is a radar anti-jamming technology to reduce the jamming efficiency of close-range false targets.

Surgery. Radar with pulse repetition frequency change or jitter will produce non-artificial aperiodic reflection echo and electronic jamming system.

The periodically reflected echo signals are dithered, thus recognizing that these signals are false targets. Electronic jamming system, unless lightning can be determined in advance.

The periodic characteristics of pulse repetition frequency jitter may make it occupy its own position in the radar it wants to interfere with and the real target it protects.

Sometimes, otherwise it is difficult to make false targets interfere with work.

(4) Moving target display, moving target detection and their compatibility with frequency agility. Moving object display is a way to use moving objects.

Doppler frequency shift of echo signal is used to eliminate the interference of fixed target echo, so that moving target can be detected or displayed. move

Target detection is a technology developed on the basis of moving target display, which can separate useful targets from clutter in frequency domain.

Reduce the interference of background clutter. These two technologies are effective measures against passive interference. However, modern radar countermeasures usually

When chaff jamming and aiming noise FM jamming are used at the same time, moving target display (or movement) is needed.

Target detection) and frequency flexibility. At present, the typical compatibility methods are: pulse group

Frequency agility? Moving object detection in the crowd; Random frequency agility? Display of moving targets with the same frequency; Four-pulse system; Intrapulse diversity-pulse

Group moving target detection, etc.

(5) Ultra-low sidelobe antenna, sidelobe blanking and sidelobe cancellation. The ultra-low sidelobe antenna is designed to make the radar in the sidelobe direction.

The probability of being found is the smallest. Ultra-low sidelobe antenna radar can realize spatial selection and limit the interference to the main lobe area.

Between; In other angles, the radar can work normally, and the angle information of jammer can be measured, and then multi-station rendezvous can be carried out.

Positioning technology for measuring the distance data of jammer. Sidelobe blanking is also a technology to deal with sidelobe interference.

An auxiliary antenna with a gain less than the main lobe gain of the main antenna and greater than the side lobe gain of the main antenna. Compare the main antenna and the auxiliary antenna respectively.

Receiver output signal: If the receiver signal of the main antenna is large, it is the signal when the antenna is aimed at the target, and it passes through

Gated signal analysis circuit; If the signal of the auxiliary antenna receiver is large, it is the signal that enters from the sidelobe, not from the sidelobe.

Is gated and cannot reach the signal analysis circuit. However, the above sidelobe blanking technology cannot deal with continuous wave or noise interference.

It is necessary to use sidelobe cancellation technology, and the method is as follows: detect the signals in the main receiver and the auxiliary receiver, and if the auxiliary receiver

When the signal power level of the antenna receiver is large, it is necessary to cancel, that is, cancel the amplitude and phase of the interference signal.

Adjust the feedback circuit in the closed loop to minimize the interference signal in the main receiver channel.

(6) Phased array system. Because phased array antenna is composed of independent radiating elements or subarrays, it is used in electronic countermeasures.

The best adaptive antenna pattern can be obtained in the environment. The digital beamforming receiver of phased array radar adopts digital technology.

Device for realizing instantaneous multi-beam and real-time adaptive processing. Instantaneous multi-beam can be formed while adapting to interference sources.

Zero adjustment, ultra-high resolution and ultra-low sidelobe are obtained, which can effectively deal with advanced integrated electronic interference.

In addition, the waveform and locking time of phased array radar can be adjusted according to the requirements of clutter environment. Therefore, phased array is undoubtedly

An excellent naval radar countermeasure system.

Contemporary naval radars with strong anti-jamming ability include American "Flaxsa" three-coordinate coherent fire control radar and British.

"Mesa" multifunctional electric scanning adaptive radar and French "Alabert" multifunctional phased array fire control radar, etc. American Frye

The main feature of "Kaiser" radar is to use computers to adaptively change mines in real time according to the principle of maximum echo information of each target.

Waveform (* * has more than 14000 waveform transitions). This real-time distributed tracking, coupled with the characteristics of Doppler waveform processing, makes this

Radar has good electronic anti-jamming and anti-clutter performance. The core technology of British Mesa radar is real-time adaptive digitization.

Beamforming technology, its main advantage is that it can suppress the interference of as many as 15 jammers, and use additional super

Resolution technology determines the position of enemy jammer (i.e. target). France's "Arab" radar has strong anti-jamming ability.

The anti-clutter ability is due to the following reasons: First, the antenna has a very low sidelobe level and is equipped with sidelobe blanking or sidelobe cancellation.

Additional channels and tracking interference sources can realize adaptive zero adjustment of antenna pattern; Secondly, radar is used in the transceiver.

Grid-controlled traveling wave tube is used to obtain beam flexibility, and perfect frequency agility is achieved through frequency agility between pulses and pulse groups.

Multiple receiving channels can ensure monitoring and tracking measurement and electronic anti-interference processing; In addition, its advanced digital signal processor can

Complete the functions of pulse compression, Doppler filtering and constant false alarm rate processing.

2 1 century prospect

Development trend of future naval electronic warfare system

(1) Develop the shipborne advanced integrated electronic warfare system (AIEWS). American shipborne An /SLQ-32 integrated electronic warfare system

Based on this, the trans-century An /SLQ-54 shipborne integrated electronic warfare system is being developed. The operating frequency spectrum of the system ranges from 2.5 to 18 GHz.

Hertz extends to light, heat and infrared range. It uses advanced computers to organically combine reconnaissance, early warning and interference.

Up can quickly intercept threat signals, accurately determine parameters and identify them in time, and can also aim at many different threats at the same time.

Various forms of interference (including active interference and passive interference); It will adapt to the high-density and extremely complex RF electromagnetism in the future.

Environment, which can provide necessary layered electronic defense for warship combat system, will have a far-reaching impact on naval radar electronic warfare in 2 1 century.

The influence of.

(2) Developing C3I (Command, Control, Communication and Intelligence) system of naval integrated electronic warfare. Electronic warfare C3I system is based on

Key technologies and equipment of 2 1 century naval radar electronic warfare. According to its functions and tasks, it can be divided into:

Single-ship platform electronic warfare C3I system (integrating the soft and hard killing of shipborne guns, missiles and other weapons)

Combat system).

C3I maritime formation tactical electronic warfare system.

Naval warfare electronic warfare of C3I system.

System-level strategic electronic warfare C3I system for homeland defense operations.

(3) Develop more advanced electronic warfare antenna technology. This kind of electronic warfare antenna should be wider and more angular than radar antenna.

Wider coverage and multi-beam function. It must solve the problems of space coverage, high beam pointing, low sidelobe and multi-channel direction finding.

Wait for questions. The new development focus will be phased array and direction-finding multipath suppression, as well as high-performance phased array modules, solid microwave components and

Fast frequency hopping transmission technology. Germany installed omnidirectional and directional antennas in a single probe to make a biconical antenna; besides

A compact three-axis stable rotating dish antenna is being developed.

(4) Develop more advanced electronic warfare information processing technology. This includes frequency agility and filtering technology, radio frequency identification and classification.

Technology, adaptive array processing and fast frequency synthesis technology, data processing and fusion technology, image processing technology and experts.

System and artificial intelligence technology. The United States plans to improve the performance and capacity of electronic warfare center computers before the arrival of the new century.

More than two orders of magnitude higher, we will focus on the development of ultra-high-speed integrated circuits, surface acoustic waves, charge coupling, Bragg gratings and other new devices.

And high-level language program modular software technology. Britain is developing a polar frequency discriminator for instantaneous frequency measurement receiver.

On the basis of this new microwave device, we strive to further improve its direct detection and instantaneous frequency measurement performance for intercepted signals.

Anti-development trend of future naval radar system

(1) The naval radar system is equipped with automatic reconnaissance calculation device and anti-radiation missile early warning system. Automatic reconnaissance and measurement

The computer device can adaptively combine various anti-jamming technologies of radar to optimize the anti-jamming effect. Anti-radiation missile warning

The system uses Doppler effect to detect the echo information of anti-radiation missiles, give an alarm automatically and take emergency measures adaptively.

Countermeasures, such as turning off radar, throwing jamming bait quickly and controlling firepower to intercept. It has a great influence on the development of anti-radiation missiles.

The current distance should be about 40 ~ 60 kilometers, which provides information for the guidance radar and decoy deflection system before shooting down the anti-radiation missile.

The required warning time is 30 ~ 60 seconds.

(2) Developing shipborne multifunctional phased array radar. Phased array radar uses its beam flexibility and adaptive scanning function,

"Power management" can be realized according to the need of anti-interference. American AN/SPY- 1 series radar is the most advanced warship in the world.

Multifunctional phased array radar. Its latest improved AN/SPY- 1D (V) radar is now being tested on land. The one with the radar

It will greatly improve the radar system's ability to capture low-altitude and high-speed targets in the global typical coastal clutter-intensive environment.

Yes, on the other hand, it will greatly enhance the radar's ability to resist deceptive electronic interference. It is the most advanced in 2 1 century.

The bane of deceptive jammer.

(3) Develop shipborne over-the-horizon radar and bistatic radar. Shipborne ground wave over-the-horizon radar can not only warn, but also

And it has potential effectiveness in dealing with stealth targets and anti-radiation missiles. The British navy was recently aboard the "London-Delhi"

The test of ground wave over-the-horizon radar on frigates shows that the radar can detect over-the-horizon sea-skimming anti-ship missiles, and its detection distance is

The distance is 2 ~ 3 times that of conventional radar. The United States combines the shipborne over-the-horizon radar system with the bistatic radar system and adopts

The transmitting antenna and transmitting station are shore-based, and the receiving and signal processing system is ship-borne. This combined system of thunder.

It has high concealment and security, and has obvious advantages in anti-stealth, anti-radiation missiles and anti-electronic interference.

Potential.

(4) Develop millimeter wave radar and plasma radar. Millimeter wave radar is between microwave and infrared, so it is also

Microwave radar has good all-weather detection ability, and infrared detection system has the characteristics of short range and high resolution.

It has narrow beam, wide frequency band and strong anti-jamming ability, and its current technical development is far ahead of the development of electronic jamming technology.

Plasma radar uses superconducting properties of ionized plasma to reflect radar beams. Plasma radar can be used in one billionth

The redirection changes the monitoring target within seconds, while the traditional radar takes about 1 ~ 10 seconds. The radar is small in size and high in power.

There is no need to install parabolic antenna of traditional radar; It can track incoming missiles and other targets at almost unlimited speed and can enter.

Gradually improve the stealth of radar and ships. This is the case with the "AgileMirror" radar being developed by the US Navy.

Plasma radar.

(5) Realize radar networking and sensor data fusion. Multi-radar networking can actively control each radar system in the network according to the enemy's situation.

The working state of the system can realize the cooperative anti-jamming working mode of radar group such as random flashing start, multi-machine receiving and fake transmitter.

The real transmitter works under hidden conditions and has the characteristics of being lured and low interception probability. The most promising networking scheme of shipborne radar is over-the-horizon (OTH).

Radar, early warning aircraft and conventional ship-borne radar are networked to form the complementarity of long, medium and short range and high, medium and low altitude.

Human detection network. In order to make up for the shortcomings of radar system, radar is integrated with sonar, infrared, photoelectric detection and other sensor equipment.

Combine them to form a multi-information integrated anti-jamming system. Multi-sensor data fusion and information sharing will make naval radar defense.

The system can better identify the nature and intention of the target.

To sum up, the world naval radar electronic warfare in 2 1 century will be more extensive and in-depth, and the combat mode will be more intense.

Equipment technology is more advanced and complex. This development trend is self-evident.