A combined active and passive centroid jamming method

Abstract

The present application provides an active and passive combined centroid jamming method, which includes calculating the long-range and short-range demarcation values of the ship. The long-range and short-range demarcation values of the ship are determined, and a multi-stage control strategy is adopted to flexibly select different jamming styles according to the distance of the incoming missile from the ship. In the long-range stage, narrowband noise jamming of the phased array active jamming equipment is adopted. In the short-range stage, an active and passive combined centroid jamming method is adopted. The present application uses a multi-stage control strategy, comprehensively considering the characteristics of the single-pulse angle measurement and tracking of the terminal guidance radar, and flexibly selects different jamming styles according to the distance of the incoming missile from the ship, thereby achieving targeted jamming of the seeker in different working stages and effectively improving the success rate of the whole process jamming.

Description

Technical Field

[0001] The present application relates to the field of electronic system integrated electronic warfare technology, and in particular to an active and passive combined centroid jamming method. Background Art

[0002] In modern warfare, electronic warfare has become an important part of dominating the battlefield. Anti-ship missiles are the biggest threat currently faced by surface ships operating at sea. Shipborne electronic warfare systems are responsible for ship and formation situational awareness, long-range early warning, regional air defense and anti-missile operations, and other combat tasks, playing a vital role in the ship's air defense and anti-missile system.

[0003] The confrontation between jamming and anti-ship missiles is a game of "spear" and "shield," a continuous and dynamically changing process. Currently, typical terminal guidance radars all use single-pulse angle tracking technology, which has strong, inherent anti-interference advantages. Given the technical characteristics of single-pulse angle tracking for anti-ship missiles, relying solely on a single active or passive jamming method has certain limitations and cannot achieve a good, sustained countermeasure effect. Therefore, how to integrate multiple methods such as active / passive, inboard / outboard jamming, and coordinate the coordinated work of various devices to achieve close coordination of active and passive jamming in the time, frequency, air, and energy domains, and effectively enhance the effectiveness of soft weapons against single-pulse angle tracking terminal guidance radars has become an urgent problem that needs to be solved. Summary of the Invention

[0004] The present application provides an active-passive combined centroid jamming method, which can be used to solve the technical problem of limitations of single active jamming in the prior art.

[0005] The present application provides an active and passive combined centroid jamming method, the method comprising:

[0006] Step 1: Determine the boundary between long-range and close-range ship;

[0007] Step 2: At long distances, use phased array active jammers to generate narrowband noise interference.

[0008] Step three: At close range, use active and passive combined centroid interference.

[0009] Optionally, criteria for determining the long-range and close-range ship separation thresholds include:

[0010] Criterion 1: When the missile attacks from the bow, that is, when the true bearing θ is 0° and the seeker signal illuminates the ship's width D, the missile's RL is 10 km.

[0011] Criterion 2: When the seeker is approaching from the normal direction of the ship, that is, the true bearing θ is 90°, and the seeker signal illuminates the ship's length L, the missile's RL is 15 km;

[0012] Criterion 3: When the seeker is attacking from another θ direction, RL is determined as follows:

[0013]

[0014] Optionally, at long range, phased array active jammers can be used to generate narrowband noise interference, including:

[0015] When the seeker is at a long range, the angle measurement error caused by noise interference is determined as follows:

[0016]

[0017] Where θB is the 3 dB beamwidth of the antenna and beam; BS is the signal bandwidth; TP is the pulse width; (S / J)1 is the signal-to-interference ratio of a single pulse; Ne is the number of effective accumulated pulses within the relevant measurement time; and 1.57 is the typical value of the detection slope of the four-horn feed single-pulse angle error sensor.

[0018] Optionally, at close range, a combined active and passive centroid jamming method is used, including:

[0019] Step 31, first use chaff bar centroid interference, the ship deploys chaff bar cloud to form chaff bar group according to the direction and distance of the incoming missile to perform centroid interference, the position of the chaff bar cloud group (see Figure 4 The following conditions are met: 1. The line connecting the seeker and the ship and the line connecting the missile and the chaff cloud meet a preset angle; 2. Both the ship and the chaff cloud are within the field of view of the seeker;

[0020] Step 32: Divide the phased array active jammer into two sub-arrays, the first sub-array and the second sub-array, and perform one detection and reception and two transmissions. The delay between transmission and reception is no more than 20% of the seeker PW.

[0021] Direct channel: The first sub-array is aligned with the seeker and directly forwards the seeker radiation signal.

[0022] Forward channel: The second sub-array is aimed at the passive chaff interference cloud and also forwards the seeker radiation signal;

[0023] Step 33, coordinated control: continuously increase the transmission power of the first sub-array and the second sub-array to displace the equivalent apparent center of the missile observing the ship. The mixed energy center formed by the missile tracking the ship, active jammer and chaff jammer gradually deviates from the ship target.

[0024] Advantages of this application include:

[0025] (1) A multi-stage control strategy is adopted, which comprehensively considers the characteristics of the single-pulse angle tracking of the terminal guidance radar. Different interference patterns are flexibly selected according to the distance between the incoming missile and the ship, thus achieving targeted interference at different working stages of the seeker and effectively improving the success rate of the whole interference process.

[0026] (2) The active and passive combined centroid jamming method is adopted to make full use of the characteristics of the phased array active jamming equipment that can be separated into array interference. By combining the phased array active jamming equipment with the passive chaff bomb, coordinated control, and comprehensive confrontation, the combined centroid jamming of the single-pulse angle tracking terminal guidance radar is achieved, effectively improving the countermeasure effectiveness of soft weapons. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the relationship between the angle measurement error caused by noise interference and the interference-to-signal ratio when the seeker is at long range;

[0028] Figure 2 This is a block diagram of the integrated countermeasure system for the monopulse angle-measuring terminal guidance radar;

[0029] Figure 3 To calculate the long-range and short-range maps for incoming missiles;

[0030] Figure 4 This is a tactical diagram of active and passive combined centroid jamming against a single-pulse angle-measuring terminal guidance radar. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0032] At present, typical terminal guidance radars all use single pulse angle tracking technology, which has a strong and inherent anti-interference advantage. Take the typical four-horn feed single pulse angle measurement system used in the seeker as an example:

[0033] Thermal noise is the primary cause of angle measurement errors at long ranges. When the seeker is at long range, the signal-to-noise ratio is low, making thermal noise the primary cause of angle measurement errors. At close ranges, the signal-to-noise ratio is high, making thermal noise negligible. However, angular glint degrades angle measurement accuracy.

[0034] When the seeker is at a long range, the angle measurement error caused by noise interference is calculated as follows:

[0035]

[0036] Where θB is the 3 dB beamwidth of the antenna and beam; BS is the signal bandwidth; TP is the pulse width; (S / J)1 is the signal-to-interference ratio of a single pulse; Ne is the number of effective accumulated pulses within the relevant measurement time; and 1.57 is the typical value of the detection slope of the four-horn feed single-pulse angle error sensor.

[0037] The relationship between the angle measurement error caused by noise interference and the interference-to-signal ratio when the seeker is at long range is as follows: Figure 1 shown.

[0038] When the seeker is at close range, the angle measurement error caused by angular flicker noise is calculated as follows:

[0039] σ q,g =(0.2~0.3)L / R (2)

[0040] Where L is the projected length of the line between the ship and the chaff cloud or active decoy onto the plane normal to the missile's angle of attack, and R is the missile-ship range. R must be within the close-range range and is related to the missile's angle of attack.

[0041] In view of the characteristics of single-pulse angle tracking of typical terminal guidance radar, this application proposes an active and passive joint centroid jamming method, which fully utilizes the characteristics of separable array interference of phased array active jamming equipment, and combines the phased array active jamming equipment with passive chaff bombs for coordinated control and comprehensive confrontation to achieve joint centroid jamming of single-pulse angle tracking terminal guidance radar, thereby effectively improving the effectiveness of soft weapon confrontation.

[0042] The long-range angle measurement error of a monopulse angle measurement system is primarily affected by thermal noise, while the close-range angle measurement error is primarily affected by target angular glint. From a countermeasures perspective, different jamming patterns need to be selected based on the distance of the incoming missile from the ship.

[0043] The integrated countermeasure system for monopulse angle-finding terminal guidance radar consists of the following three components:

[0044] (1) Sensors: broadband radar reconnaissance subsystem and radar equipment of the platform;

[0045] (2) System processing and dispatching center: comprehensive information processing, comprehensive dispatching control;

[0046] (3) Soft weapons: active and passive jamming equipment such as phased array active jamming equipment and outboard jamming equipment.

[0047] The block diagram of the integrated countermeasure system for the single pulse angle measurement terminal guidance radar is as follows: Figure 2 shown.

[0048] The method provided in this application has the following specific steps:

[0049] Step 1: Determine the long-range and close-range dividing values for ships:

[0050] Due to the use of a multi-stage control strategy, different jamming patterns can be flexibly selected according to the distance of the incoming missile from the ship. The following criteria are used to determine the threshold between long-range and close-range ship:

[0051] (1) A ship is not a uniform sphere, and its RCS in different directions is different;

[0052] (2) When observing a ship from the missile's perspective, if it is viewed as a point target, the missile is considered to be at a long range; if it is viewed as a volume target, the missile is considered to be at a close range;

[0053] (3) Determine the long-range and short-range boundary value RL based on the length and width projections of the ship on the normal plane in the direction of the incoming missile. Taking a certain ship as an example, consider the missile approaching in a sea-skimming manner. For the time being, the effect of the ship's height on the long and short ranges is not considered. Therefore, the RL will be different for different missile attack directions. In other words, RL cannot be calculated using a static method, but should be determined based on the missile's attack direction θ and the ship's RCS.

[0054] Therefore, the calculation criteria for the long-range and close-range separation values of ships are as follows:

[0055] (1) When the missile approaches from the bow, that is, the true bearing θ is 0°, and the seeker signal illuminates the ship's width D, the missile's RL is 10 km;

[0056] (2) When the seeker is approaching from the normal direction of the ship, that is, the true bearing θ is 90°, and the seeker signal illuminates the ship's length L, the missile's RL is 15 km;

[0057] (3) When the seeker is attacking from another θ direction, RL is determined as follows:

[0058] R L =10cosθ+15sinθ(unit: km) (3)

[0059] Step 2: At long distances, use phased array active jammers to generate narrowband noise interference.

[0060] At long range, phased array active jammers use narrowband noise interference to increase the seeker's tracking error of the ship, disrupting the seeker's stable tracking of the ship. When the seeker is at long range, the angle measurement error caused by noise interference is determined as follows:

[0061]

[0062] Where θB is the 3 dB beamwidth of the antenna and beam; BS is the signal bandwidth; TP is the pulse width; (S / J)1 is the signal-to-interference ratio of a single pulse; Ne is the number of effective accumulated pulses within the relevant measurement time; and 1.57 is the typical value of the detection slope of the four-horn feed single-pulse angle error sensor.

[0063] Step 3: At close range, use active and passive combined centroid jamming.

[0064] Step 31, first use chaff bar centroid interference, the ship deploys chaff bar cloud to form chaff bar group according to the direction and distance of the incoming missile to perform centroid interference, the position of the chaff bar cloud group (see Figure 4 ) meets the following conditions: 1. The line connecting the seeker and the ship and the line connecting the missile and the chaff cloud meet the preset angle 2. The ship and the chaff cloud are both within the field of view of the seeker.

[0065] Step 32, fully utilizing the advantage of the phased array active jammer capable of divisible array interference, the phased array active jammer is divided into two sub-arrays, the first sub-array and the second sub-array, to perform one detection and two transmissions, with the delay between transmission and reception being no more than 20% of the seeker PW.

[0066] Direct channel: The first sub-array is aligned with the seeker and directly forwards the seeker radiation signal (appropriately modulated with narrowband noise).

[0067] Forwarding channel: The second sub-array is aimed at the passive chaff interference cloud and also forwards the seeker radiation signal (appropriately modulated with narrowband noise).

[0068] Step 33, coordinated control: continuously increase the transmission power of the first sub-array and the second sub-array to displace the equivalent apparent center of the missile observing the ship. The mixed energy center formed by the missile tracking the ship, active jammer and chaff jammer gradually deviates from the ship target.

[0069] This application does not use a sub-array to alternately fire directly at the missile and directly at the chaff, because there is a delay between the alternation, which results in a gap between the active interference signal received by the missile receiver and the signal scattered by the chaff cloud. In addition, the channel length of the chaff cloud scattering is longer than the direct interference signal channel, and there is also a gap in the time domain. Therefore, under the condition that the sub-array interference power allows, a sub-array method is used to perform combined interference.

[0070] By combining phased array active jamming equipment with passive chaff bombs, active jamming is used first at long distances, and active jamming + chaff centroid jamming is used at close ranges. Through coordinated control and comprehensive confrontation, joint centroid jamming of the terminal guidance radar with single-pulse angle tracking can be achieved, thereby effectively improving the effectiveness of soft weapon confrontation.

[0071] Active and passive combined centroid jamming tactics for single pulse angle terminal guidance radar Figure 4 shown.

[0072] The above-described embodiments of the present application do not constitute a limitation on the scope of protection of the present application.

Claims

1. An active and passive combined centroid jamming method, characterized in that: The method comprises: Step 1: Determine the boundary between long-range and close-range ship; Step 2: At long distances, use phased array active jammers to generate narrowband noise interference. Step 3: At close range, use active and passive combined centroid jamming. The criteria for determining the long-range and close-range demarcations for ships include: Rule 1: When the missile attacks from the bow, that is, the true bearing θ is 0°, and the seeker signal illuminates the ship's width D, the missile's R L 10km; Criterion 2: When the seeker is attacking from the normal direction of the ship, that is, the true bearing θ is 90°, and the seeker signal illuminates the ship's length L, the missile's R L 15km; Criterion 3: When the seeker is attacking from other θ directions, determine R L : R L =10 cosθ+15 sinθ(unit: km) (3) At close range, a combined active and passive centroid jamming method is used, including: Step 31: First, chaff centroid jamming is performed. The ship deploys a chaff cloud based on the azimuth and distance of the incoming missile to form a chaff cluster for centroid jamming. The position of the chaff cloud cluster meets the following conditions:

1. The line connecting the seeker head and the ship and the line connecting the missile and the chaff cloud meet a preset angle.

2. Both the ship and the chaff cloud cluster are within the field of view of the seeker head. Step 32: Divide the phased array active jammer into two sub-arrays, the first sub-array and the second sub-array, and perform one detection and two transmissions, with the delay between transmission and reception being no greater than 20% of the seeker PW; Direct channel: The first sub-array is aligned with the seeker and directly forwards the seeker radiation signal; Forward channel: The second sub-array is aimed at the passive chaff interference cloud and also forwards the seeker radiation signal; Step 33, coordinated control: continuously increase the transmission power of the first sub-array and the second sub-array to displace the equivalent apparent center of the missile observing the ship. The mixed energy center formed by the missile tracking the ship, active jammer and chaff jammer gradually deviates from the ship target.

2. The method according to claim 1, characterized in that At long distances, phased array active jammers are used to generate narrowband noise interference, including: When the seeker is at a long range, the angle measurement error caused by noise interference is determined as follows: Among them, θ B is the 3dB beamwidth of the antenna and beam; B S is the signal bandwidth; T P is the pulse width; (S / J)1 is the signal-to-interference ratio of a single pulse; N e is the number of effective accumulated pulses within the relevant measurement time; 1.57 is the typical value of the detection slope of the four-horn feed single-pulse angle error sensor.

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