CN112986938B - A collaborative deception jamming method based on UAV formation - Google Patents

Abstract

The invention relates to the technical field of radar interference, in particular to a cooperative deception interference method based on unmanned aerial vehicle formation. The method comprises the following steps: forming a formation of unmanned aerial vehicles by four unmanned aerial vehicle carrying the jammers; after the jammer receives radar pulse, carrying out jammer pairing on unmanned aerial vehicle formation according to the incoming wave signal direction to form two interference loops; forwarding radar pulses with minimum delay time, and capturing a range gate of the monopulse radar; the interference machine gradually increases the forwarding delay time, so that the distance wave gate gradually deviates from the platform to reflect echo, the interference signal to interference ratio in the distance wave gate is continuously increased, the interference gain is continuously increased, and the angle measurement error is increased; and after the platform reflection echo moves out of the range gate, increasing the angle measurement error until the monopulse radar is unlocked. The embodiment of the invention can keep a more stable interference effect under any rotation angle of the interference machine.

Description

A collaborative deception jamming method based on UAV formation

Technical field

The invention relates to the technical field of radar interference, and in particular to a collaborative deception interference method based on UAV formation.

Background technique

Monopulse radar is a tracking radar that can obtain all angular coordinate information of the target from a single echo pulse signal. Due to its high angle measurement accuracy and strong anti-interference ability, monopulse radar is widely used in artillery control, target tracking, missile guidance and other fields, posing a major threat to modern military systems. Since traditional jamming methods are difficult to jam monopulse radars, jamming monopulse radars has become a research hotspot in the field of Electronic Warfare (EW). Domestic and foreign scholars have taken advantage of the flaws in the design and manufacturing of monopulse radars and proposed interference methods for monopulse radars such as towed decoy interference, cross-polarization interference, formation interference, and cross-eye interference. Among them, cross-eye interference is considered to be the most effective interference pattern for monopulse radar.

With the extensive application of intelligent drone technology in the military field, drone swarm operations will be an important combat style in future wars.

In practice, the inventor found that the above-mentioned prior art has the following defects:

Limited by the strict parameter tolerance of traditional two-source cross-eye interference technology, small space carriers such as drones and small aircraft cannot achieve better interference effects, limiting the application of cross-eye interference technology; traditional reverse cross-eye interference Since the interference units of the scheme are linearly arranged, their interference effect will be affected by the rotation angle of the interference platform. When the monopulse radar is on the side of the two-point source reverse cross-eye jammer, that is, when the rotation angle of the jammer is larger, the interference effect will be smaller. Difference.

Contents of the invention

In order to solve the above technical problems, the purpose of the present invention is to provide a collaborative deception jamming method based on UAV formation. The technical solution adopted is as follows:

One embodiment of the present invention provides a collaborative deception jamming method based on UAV formation, which method includes the following steps:

A drone formation consists of four drones equipped with jammers, and the drone formation is arranged in a square;

After the jammer receives the radar pulse, it pairs the jammers in the UAV formation according to the direction of the incoming signal, forming two jamming loops. Each jamming loop contains two paired jamming units, forming a UAV formation. The spatial configuration of the adaptive multi-loop anti-phase cross-eye interference; forwards the radar pulse with the minimum delay time to capture the range gate of the single-pulse radar;

The jammer gradually increases the forwarding delay time, causing the range gate to gradually deviate from the platform reflection echo. The interference-to-signal ratio in the range gate continues to increase, the interference gain continues to increase, and the angle measurement error increases; the interference-to-signal ratio is the same for all platforms. The ratio of the sum of the amplitudes of the reflected echoes to the sum of the amplitudes of the multi-channel interference signals. The interference-to-signal ratio is positively correlated with the interference gain;

When the platform reflection echo moves out of the range gate, the angle measurement error increases until the monopulse radar loses lock.

Preferably, the jammer pairing method is:

According to the angle between the direction of the incoming wave signal and the forward direction of the UAV formation, the pairing of the interference units is changed. The forward direction of the UAV formation is any diagonal direction of the square.

Preferably, when the angle between the direction of the incoming wave signal and the forward direction of the UAV formation is 0° to 90° or -90° to -180°, the pairing of the interference units is the first interference mode as the forward direction. The two UAVs on the diagonal line serve as the first interference unit and the fourth interference unit respectively. With the diagonal line as the dividing line, the interference unit closest to the incoming wave signal and the interference unit located on the diagonal line with the incoming wave signal The interference units on the same side are paired; the first interference loop of the first interference mode includes the paired first interference unit and the second interference unit; the second interference loop of the first interference mode includes the paired third interference unit and the third interference unit. Four interference units; the first interference unit and the fourth interference unit respond to external signals.

Preferably, when the angle between the direction of the incoming wave signal and the forward direction of the UAV formation is 90° to 180° or 0° to -90°, the pairing of the interference units is the second interference mode as the forward direction. The two UAVs on the diagonal line serve as the first interference unit and the fourth interference unit respectively. With the diagonal line as the dividing line, the interference units closest to the incoming signal and those located on the same diagonal as the incoming signal are The interference units on both sides are paired; the first interference loop of the second interference mode includes the paired first interference unit and the third interference unit; the second interference loop of the second interference mode includes the paired second interference unit and the fourth The interference unit; the first interference unit and the fourth interference unit respond to external signals.

Preferably, the working mode of the first interference mode is:

The signal received by the first interference unit is modulated by amplitude gain and phase offset and then transmitted to the second interference unit, and then transmitted by the second interference unit; the signal received by the second interference unit is directly forwarded to the first interference unit, and then transmitted by the second interference unit. One interference unit transmits; the signal received by the third interference unit is modulated by amplitude gain and phase offset and forwarded to the fourth interference unit, and then transmitted by the fourth interference unit; the signal received by the fourth interference unit is directly forwarded to the third interference unit , and then transmitted by the third interference unit.

Preferably, the working mode of the second interference mode is:

The signal received by the first interference unit is modulated by amplitude gain and phase offset and then transmitted to the third interference unit, and then transmitted by the third interference unit; the signal received by the third interference unit is directly forwarded to the first interference unit, and then transmitted by the third interference unit. One interference unit transmits; the signal received by the second interference unit is modulated by amplitude gain and phase offset and then forwarded to the fourth interference unit, which is then transmitted; the signal received by the fourth interference unit is directly forwarded to the second interference unit , and then transmitted by the second interference unit.

Preferably, the method of capturing the range gate is:

Increase the amplitude difference in the interference modulation direction to improve the sum channel echo of the monopulse radar to capture the range gate; the interference modulation direction is the transmission direction after amplitude and phase modulation of the received signal within the interference loop.

Preferably, after the target echo moves out of the range gate, the method of increasing the angle measurement error is:

Modulating the amplitude gain of the two interference loops enables the adaptive multi-loop reverse cross-eye interference to obtain high cross-eye gain, thereby increasing the angle measurement error.

Preferably, the interference-to-signal ratio is adjusted by mismatching the interference loop amplitude ratio and the interference loop phase difference of the interference loop to obtain a higher interference-to-signal ratio.

Preferably, the interference-to-signal ratio is greater than 20dB.

The invention has the following beneficial effects:

1. The embodiment of the present invention uses UAV formation to form an adaptive multi-loop anti-phase cross-eye interference, which can maintain a stable interference effect at any jammer angle.

2. The embodiment of the present invention can improve the interference-to-signal ratio of reverse cross-eye interference, increase the interference gain, and improve the interference effect through the combination of adaptive multi-loop anti-phase cross-eye interference and range gate interference.

Description of the drawings

In order to more clearly explain the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description The drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a flow chart of a collaborative deception jamming method based on UAV formation provided by an embodiment of the present invention;

Figure 2 is a schematic curve diagram of the angle measurement error produced by a monopulse radar under different jammer rotation angles caused by two types of reverse cross-eye interference provided by an embodiment of the present invention;

Figure 3 is a schematic diagram of the geometric relationship of adaptive multi-loop reverse cross-eye interference provided by an embodiment of the present invention;

Figure 4 is a graph showing the relationship between the interference-to-signal ratio and the median interference gain simulation experiment provided by one embodiment of the present invention;

Figure 5 is an example diagram of the normalized interference-to-signal ratio gain when a ₂ =-0.5dB and φ ₂ =175° provided by an embodiment of the present invention;

Figure 6 is a contour diagram of the interference-to-signal ratio when a ₂ =-0.5dB and φ ₂ =175° provided by an embodiment of the present invention.

Detailed ways

In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended purpose of the invention, the following is a collaborative deception jamming method based on UAV formation proposed in accordance with the present invention in conjunction with the drawings and preferred embodiments. The specific implementation, structure, characteristics and efficacy are described in detail as follows. In the following description, different terms "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, the specific features, structures, or characteristics of one or more embodiments may be combined in any suitable combination.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which the invention belongs.

The specific scheme of the collaborative deception jamming method based on UAV formation provided by the present invention will be described in detail below with reference to the accompanying drawings.

Please refer to Figure 1, which shows a flow chart of a collaborative deception jamming method based on UAV formation provided by an embodiment of the present invention. The method includes the following steps:

In step S001, four drones equipped with jammers form a drone formation, and the drone formation is arranged in a square.

The size of small UAVs is small, with a wingspan of generally 1 to 2m. If the interference antenna pair is installed on a small UAV, limited by the size of the UAV, the interference baseline will be too short to produce larger interference. Angle measurement error will affect the effect of cross-eye interference.

The embodiment of the present invention designs a UAV formation composed of four UAVs arranged in a square. The forward direction of the UAV formation is any diagonal direction of the square. Each UAV is equipped with a jammer. , wireless communication is used between jammers, and the jammers of two UAVs form a jammer pair to ensure the length of the interference baseline.

Step S002, after the jammer receives the radar pulse, it pairs the jammers in the UAV formation according to the direction of the incoming wave signal to form two jamming loops. Each jamming loop contains two paired jamming units; the radar pulse Transmit with minimum delay time to capture the range gate of monopulse radar.

Referring to Figure 3, the radar aperture length is _dr and the distance between jammers is d _c . The distance from the geometric center of the UAV formation to the center point of the monopulse radar is r. The direction from the radar center point to a certain jammer relative to the direction to the center point of the nth jamming loop is the half-opening angle θ _en , and the rotation angle of the radar's boresight direction relative to the direction from the radar to the center of the nth jamming loop is the radar Rotation angle θ _rn , the rotation angle of the nth interference loop's boresight direction relative to its direction to the radar center is θ _cn .

Specific steps include:

1) According to the angle θ _s between the direction of the incoming signal and the forward direction of the UAV formation, change the pairing of the interference units and the corresponding transmission direction to form an adaptive multi-loop response for the UAV formation. Spatial configuration of cross-eye interference. Specific steps include:

a) When the angle between the direction of the incoming wave signal and the forward direction of the UAV formation is 0° to 90° or -90° to -180°, the pairing of the interference unit is the first interference mode, with the direction of the advance being The two UAVs on the diagonal line serve as the first interference unit and the fourth interference unit respectively. With the diagonal line as the dividing line, the interference units closest to the incoming signal and those located on the same diagonal as the incoming signal are The interference units on both sides are paired; the first interference loop of the first interference mode includes the paired first interference unit and the second interference unit; the second interference loop of the first interference mode includes the paired third interference unit and the fourth The interference unit; the first interference unit and the fourth interference unit respond to external signals.

The working mode of the first interference mode is:

The signal received by the first interference unit is modulated by amplitude gain and phase offset and then transmitted to the second interference unit, and then transmitted by the second interference unit; the signal received by the second interference unit is directly forwarded to the first interference unit, and then transmitted by the second interference unit. One interference unit transmits; the signal received by the third interference unit is modulated by amplitude gain and phase offset and forwarded to the fourth interference unit, and then transmitted by the fourth interference unit; the signal received by the fourth interference unit is directly forwarded to the third interference unit , and then transmitted by the third interference unit.

b) When the angle between the direction of the incoming wave signal and the forward direction of the UAV formation is 90° to 180° or 0° to -90°, the pairing of the interference unit is the second interference mode to serve as the counterpart of the forward direction. The two UAVs on the diagonal line serve as the first interference unit and the fourth interference unit respectively. With the diagonal line as the dividing line, the interference unit closest to the incoming wave signal and the interference unit located on the same side of the diagonal line as the incoming wave signal The interference units are paired; the first interference loop of the second interference mode includes the paired first interference unit and the third interference unit; the second interference loop of the second interference mode includes the paired second interference unit and the fourth interference unit units; the first interference unit and the fourth interference unit respond to external signals.

The working mode of the second interference mode is:

The signal received by the first interference unit is modulated by amplitude gain and phase offset and then transmitted to the third interference unit, and then transmitted by the third interference unit; the signal received by the third interference unit is directly forwarded to the first interference unit, and then transmitted by the third interference unit. One interference unit transmits; the signal received by the second interference unit is modulated by amplitude gain and phase offset and then forwarded to the fourth interference unit, which is then transmitted; the signal received by the fourth interference unit is directly forwarded to the second interference unit , and then transmitted by the second interference unit.

It should be noted that in any case of interference unit pairing and interference direction modulation, the value range of the interference rotation angle θ _cn is [-π/4, π/4]. When the first interference unit and the second interference unit When the interference units are paired, when the third interference unit is paired with the fourth interference unit, the modulation direction is from the first interference unit to the second interference unit, and from the third interference unit to the fourth interference unit. When the first interference unit is paired with the third interference unit, and the second interference unit is paired with the fourth interference unit, the modulation direction is from the first interference unit to the third interference unit, and from the second interference unit to the fourth interference unit. The amplitude gain and phase offset of any interference loop are a _n and φ _n respectively. In the embodiment of the present invention, the amplitude gains of the two sets of interference loops in the interference modulation direction are a ₁ and a ₂ respectively, and the phase offsets are φ ₁ and φ ₂ respectively.

It should be noted that for adaptive multi-loop reverse cross-eye interference composed of UAV formations, the greater the cross-eye gain, the greater the angle measurement error generated by the monopulse radar, and the better the interference effect.

Please refer to Figure 2, which shows the curves of the angle measurement errors produced by the monopulse radar under different jammer rotation angles due to two reverse cross-eye jammers. It can be seen from the figure that when the jammer rotation angle is ±90°, that is, when the monopulse radar is located at the end of the two point sources' reverse cross-eye jamming antenna array, the angle measurement error θ _d =0, at this time the two point sources are reverse Cross-eye interference fails. The angle measurement error θ _d of the adaptive multi-loop reverse cross-eye interference is always greater than 0, indicating that the adaptive multi-loop directional cross-eye interference can maintain effective interference for monopulse radars in any incoming wave direction.

2) Forward the radar pulse with the minimum delay time and increase the amplitude difference in the interference modulation direction to improve the sum channel echo of the single-pulse radar to capture the range gate. The interference modulation direction is the transmission direction after amplitude and phase modulation of the received signal within the interference loop.

Signals from different interference loops cancel each other out in the monopulse radar channel, causing the cross-eye gain to decrease. The greater the phase difference between the interference loops, the more serious the interference signal cancellation, and the more stringent the system parameter tolerance. Therefore, the interference loop phase difference will have a serious impact on the reverse cross-eye interference. Especially when the amplitude ratio and phase difference in the modulation direction approach the ideal value, the angle factor will change continuously and rapidly uncontrollably, seriously affecting the cross-eye interference. interference stability. Therefore, cross-eye interference is more sensitive to phase mismatch, the interference loop amplitude difference has less impact on the system parameter tolerance of cross-eye interference, and it is easier for the jammer to adjust the amplitude. Therefore, during the acquisition period, the interference modulation is increased by The amplitude difference in the direction is used to enhance the monopulse radar and channel echo to capture the radar wave gate.

It should be noted that since the interference signal and the echo pulse basically coincide, the interference signal in the radar gate is relatively low, and the amplitude mismatch reduces the cross-eye gain, so the angle measurement error generated by the monopulse radar at this time is small.

The calculation steps of cross-eye gain include:

When there is an interference loop difference, the total sum channel and difference channel echoes of the monopulse radar are respectively

P _n =P _r (θ _rn -θ _en )P _c (θ _cn -θ _en )P _r (θ _rn +θ _en )P _c (θ _cn +θ _en )

Among them, P _r (θ _rn ±θ _en ) is the gain of the radar antenna beam in the direction of θ _rn ±θ _en , and P _c (θ _cn ±θ _en ) is the antenna beam of the nth interference loop in the direction of θ _cn ±θ _en The gain in the direction, β = 2π/λ, is the spatial phase constant.

Among them, β=2π/λ is the spatial phase constant.

Then the single pulse ratio is

in, Represents the modulation result after amplitude gain and phase offset,/> To take the imaginary part operation.

Since the distributed multi-point source cross-eye jammer is located in the radiation far field of the monopulse radar antenna, d _cn ＜＜r, θ _en ＜＜βd _r , the value of the half-opening angle θ _en of the jamming antenna is very small, θ _cn ≈ θ _c1 , θ _rn ≈ θ _r1 , k _rn and k _cn can be simplified to

P _n ≈P _r ² (θ _r1 )P _c ² (θ _c1 )

Substitute into the single pulse ratio formula

in, is the interference loop difference between different interference loops, a′ _n is the amplitude ratio between the nth interference loop and the first interference loop,/> is the phase difference between the nth interference loop and the first interference loop;/> To take the real part operation.

Then the cross-eye gain is

Therefore, the interference loop difference will have an impact on the cross-eye gain, thereby affecting the interference performance and system parameter tolerance. In severe cases, it will change the sign of the cross-eye gain, making the cross-eye interference unable to stably produce false targets on the same side, or causing the cross-eye interference to stably produce false targets on the same side. The jammer becomes a beacon, seriously affecting the effect of cross-eye jamming.

Step S003, the jammer gradually increases the forwarding delay time, causing the range gate to gradually deviate from the platform reflection echo. The interference-to-signal ratio in the range gate continues to increase, the interference gain continues to increase, and the angle measurement error increases; the interference-to-signal ratio It is the ratio of the sum of the amplitudes of the reflected echoes from all platforms to the sum of the amplitudes of multi-channel interference signals. The interference-to-signal ratio is positively correlated with the interference gain.

Although monopulse radar has high angle measurement accuracy and strong anti-interference ability in terms of angle, it still needs to complete detection and tracking in distance first. The distance detection and tracking circuit and automatic gain control (Automatic Gain Control) of monopulse radar Control, AGC) circuits are not significantly different from ordinary radars, and their anti-interference capabilities are relatively weak. Therefore, the distance deception interference of ordinary radars can also interfere with single-pulse radars.

Range gate towing interference is a deception jamming method for range automatic tracking systems. It is mainly used as self-defense jamming and can be divided into three stages: capture period, towing period and stop tow period. The expression of the false target distance function R _f (t) of the range gate drag interference is:

Among them, R is the initial distance of the target, v is the uniform towing speed, a is the uniformly accelerating towing speed, and T _j is the longest interference time of a single interference cycle.

0≤t<t ₁ is the capture period. After intercepting the radar pulse, the jammer amplifies it and forwards it directly with the minimum delay. The amplified signal is to capture the AGC circuit of the radar receiver. Due to the response time of the AGC circuit, the gate capture phase Generally lasts about 1s. t ₁ ≤ t < t ₂ is the drag period. When the jammer captures the radar range gate, it gradually increases the pulse forwarding delay, causing the range gate to gradually deviate from the target echo. t ₂ ≤ t < T _j is the stop delay period. When the range gate is completely dragged away from the target echo, the jammer is turned off, causing the tracking radar to lose the target and re-enter the search state. After the radar re-locks on the target, the jammer repeats the process. The forwarding delay expression of range gate drag interference is:

In the embodiment of the present invention, the adaptive multi-loop reverse cross-eye interference is combined with the range gate drag interference to perform range-angle two-dimensional combined interference to isolate the platform reflection echo and eliminate the impact of the platform reflection echo. Cross-eye interference effect, obtain higher interference gain and achieve better interference effect.

Specifically, the jammer gradually increases the forwarding delay, causing the range gate to gradually deviate from the platform reflection echo. When the platform reflection echo gradually moves out of the range gate, the interference-to-signal ratio in the radar gate continues to increase, and the interference gain will gradually Increasing the cross-eye gain when the platform is close to the reflected echo increases the angle measurement error.

The specific calculation steps of interference gain include:

The normalized gain S _m of the sum channel and the normalized gain D _m of the difference channel of the monopulse radar in the direction of the jammer m are respectively:

Among them, n represents the nth interference loop, and the plus and minus signs "±" represent interference units close to and far away from the monopulse radar respectively.

Then the total platform echo S _s of the UAV formation in the monopulse radar and channel and the total platform echo D _s in the difference channel are respectively:

in, Indicates the echo reflected from the platform of the mth jammer.

Add the interference signal and the platform reflection echo to get the total difference channel echo:

Since the UAV formation is under radar far-field conditions and the value of θ _en is very small, the following approximation is used:

P _r (θ _rn +θ _en )P _r (θ _rn -θ _en )≈[P _r (θ _r1 )] ²

P _c (θ _cn +θ _en )P _c (θ _cn -θ _en )≈[P _c (θ _c1 )] ²

P _n ≈P _r ² (θ _r1 )P _c ² (θ _c1 )

Then the total pulse ratio when there is platform echo is:

Then the interference gain is:

From the formula of interference gain, it can be concluded that the platform reflection echo and interference signal will be added in the single pulse radar and channel, while the result of the difference channel remains unchanged, so the interference gain is greatly reduced.

The interference-to-signal ratio of cross-eye interference is defined as the ratio of the sum of the amplitudes of reflected echoes from each platform to the sum of the amplitudes of multi-channel interference signals. Define a _J and φ _J as

Among them, a _J represents the ratio of the sum of the echo signal amplitudes of all platforms to the sum of the amplitudes of all interference signals, and φ _J represents the ratio of the sum of the phases of the echo signals from all platforms to the sum of the phases of all interference signals.

Due to factors such as the radar cross section (RCS) attitude sensitivity of the radar target and jitter during flight, the platform echo phase will change randomly within [0, 2π], so it is assumed that φ _J is in [0 , 2π] uniformly distributed, then the interference-to-signal ratio expression according to the definition is

Then the interference gain including the platform echo is

When k _n is an arbitrary constant and θ is uniformly distributed within the value range, the form is as follows

The median f _m of f in the expression is

Therefore, the interference gain median G _ctm is

It can be concluded from the interference gain median calculation formula that when JSR=1, the value of the interference gain median G _ctm is half of the cross-eye gain of the isolated echo.

The interference-to-signal ratio determines the proportion of the total cross-eye gain median G _ctm to the cross-eye gain of the isolated echo, and the total cross-eye gain median G _ctm reflects the distribution of the total cross-eye gain. When the interference-to-signal ratio is larger, The closer the total cross-eye gain median G _ctm is to the cross-eye gain of the isolation echo, the less the total cross-eye gain is affected by the platform echo.

In the embodiment of the present invention, a simulation experiment is performed to analyze the relationship between the interference-to-signal ratio and the interference gain median. Please refer to Figure 4. The interference gain median G _ctm increases monotonically with the interference-to-signal ratio JSR. According to the interference gain median calculation formula, when JSR=0dB, the interference gain median G _ctm is half of the isolation echo cross-eye gain G _c . Therefore, when the interference-to-signal ratio JSR>20dB, the interference gain median G _ctm is very Close to the cross-eye gain G _c of the isolated echo, the interference signal plays a major role in the single pulse and channel echo. The impact of the platform reflection echo on the cross-eye interference is very small. The actual cross-eye interference effect can be close to that of the non-platform echo. Cross-eye interference effect in cases. When the interference-to-signal ratio JSR is greater than 20dB, the growth rate of the interference gain median G _ctm slows down significantly, and the cross-eye interference effect improved by increasing the interference-to-signal ratio JSR is not obvious. Therefore, in order to achieve the ideal interference effect, the interference-to-signal ratio JSR should be greater than 20dB during actual cross-eye interference.

further, according to

inferred

It can be seen that the interference-to-signal ratio JSR is related to the parameter value of the interference loop. The interference parameters are the interference loop amplitude ratio and the interference loop phase difference.

In the embodiment of the present invention, the interference-to-signal ratio JSR under the ideal parameters of cross-eye interference is used to normalize the interference-to-signal ratio JSR under different interference loop parameters to analyze the effect of the interference loop parameters on the interference-to-signal ratio JSR. For the impact, please refer to Figure 5 and Figure 6. Figure 5 shows a ₂ =-0.5dB, φ ₂ =175° normalized JSR gain example plot, and Figure 6 shows a ₂ =-0.5dB, φ ₂ = 175° JSR contour map. The contour is a set of closed solutions to the mismatch values of a ₁ and φ ₁ for a fixed JSR gain value. A ₂ and φ ₂ take fixed values and are used to normalize the interference-to-signal ratio. The ideal interference parameter value of JSR satisfies a ₁ +a ₂ =0dB, φ ₁ +φ ₂ =360°.

According to Figure 5, it can be seen that the farther the interference parameters of adaptive multi-loop reverse cross-eye interference are from the ideal value, that is, the more serious the interference loop amplitude ratio and phase difference mismatch, the greater the normalized interference-to-signal ratio JSR gain, which It is due to the amplitude ratio and phase difference mismatch that the interference echo amplitude in the monopulse radar and channel increases.

According to Figure 6, it can be seen that when the mismatch values of a ₁ and φ ₁ are on the contour line, a normalized JSR gain corresponding to a higher value than the ideal interference parameter value can be obtained.

Therefore, by mismatching the interference loop amplitude ratio and the interference loop phase difference, a higher interference-to-signal ratio can be obtained.

Step S004: After the platform reflection echo moves out of the range gate, the angle measurement error is increased until the monopulse radar loses lock.

specific:

When the platform reflected echo signal moves out of the range gate, the interference signal in the range gate is relatively high at this time, and the amplitude of the two interference signals is modulated again, so that the adaptive multi-loop reverse cross-eye interference can obtain high cross-eye gain. Increase the angle measurement error until the monopulse radar loses lock.

According to step S003, in order to obtain a higher interference-to-signal ratio, the interference parameters can be reasonably configured to mismatch the amplitude ratio and phase difference of the interference loop, thereby improving the interference-to-signal ratio and interference at the expense of reducing the cross-eye gain of the isolated echo. gain. Therefore, for range-angle two-dimensional combined interference, in the early stage of interference, it is necessary to mismatch the amplitude ratio and phase difference of the interference loop, reduce the cross-eye gain, and increase the interference-to-signal ratio to ensure the success rate of distance towing interference. After the radar gate, the interference parameters are adjusted to improve the cross-eye interference effect.

The range gate drag interference can improve the interference-to-signal ratio of the reverse cross-eye interference, increase the cross-eye gain, and improve the effect of angle interference. The reverse cross-eye interference can make the false target have angle information, making the range gate drag Cause interference is more difficult to identify.

To sum up, the embodiment of the present invention forms an adaptive multi-loop reverse cross-eye interference through a formation of UAVs equipped with jammers, and combines it with the range gate interference to form a range-angle two-dimensional combined interference. According to the incoming wave signal The interference units are paired in the direction to form an interference loop, and the radar pulse is forwarded with the minimum delay time to capture the range gate; the jammer gradually increases the forwarding delay time, causing the range gate to gradually deviate from the platform reflection echo, increasing Angle measurement error; when the platform reflection echo moves out of the range gate, the angle measurement error continues to increase until the monopulse radar loses lock. The embodiment of the present invention can maintain a more stable interference effect at any jammer angle, can basically eliminate the influence of platform echo when the interference-to-signal ratio is greater than 20dB, and implement cross-eye interference at a lower interference-to-signal ratio.

It should be noted that the above-mentioned order of the embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. Specific embodiments of this specification have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve desired results. Additionally, the processes depicted in the figures do not necessarily require the specific order shown, or sequential order, to achieve desirable results. Multitasking and parallel processing are also possible or may be advantageous in certain implementations.

Each embodiment in this specification is described in a progressive manner. The same and similar parts between the various embodiments can be referred to each other. Each embodiment focuses on its differences from other embodiments.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (10)

1. A co-spoofing type jamming method based on unmanned aerial vehicle formation, which is characterized by comprising the following steps:

forming an unmanned aerial vehicle formation by four unmanned aerial vehicle carrying the jammers, wherein the unmanned aerial vehicle formation is in square arrangement;

after the jammer receives radar pulses, carrying out jammer pairing on the unmanned aerial vehicle formation according to the incoming wave signal direction to form two interference loops, wherein each interference loop comprises two paired interference units to form a self-adaptive multi-loop reverse phase cross eye interference spatial configuration for the unmanned aerial vehicle formation; forwarding the radar pulse with minimum delay time, and capturing a range gate of the monopulse radar;

the interference machine gradually increases the forwarding delay time, so that the distance wave gate gradually deviates from the platform to reflect echo, the interference signal ratio in the distance wave gate is continuously increased, the interference gain is continuously increased, and the angle measurement error is increased; the interference signal ratio is the ratio of the sum of the amplitudes of all the platform reflection echoes to the sum of the amplitudes of the multipath interference signals, and the interference signal ratio and the interference gain are in positive correlation;

and after the platform reflection echo moves out of the range gate, increasing the angle measurement error until the monopulse radar is out of lock.

2. The method of claim 1, wherein the method of jammer pairing is:

according to the included angle between the incoming wave signal direction and the advancing direction of the unmanned aerial vehicle formation, the pairing of the interference units is changed, and the advancing direction of the unmanned aerial vehicle formation is any diagonal direction of a square.

3. The method according to claim 2, wherein when the angle between the incoming wave signal direction and the advancing direction of the unmanned aerial vehicle formation is 0 ° to 90 ° or-90 ° to-180 °, the pairing of the interference units is a first interference pattern, two unmanned aerial vehicles on the diagonal line as the advancing direction are respectively used as a first interference unit and a fourth interference unit, and the diagonal line is used as a dividing line, and the interference unit closest to the incoming wave signal and the interference unit on the same side of the diagonal line as the incoming wave signal are paired; the first interference loop of the first interference mode comprises a first interference unit and a second interference unit which are paired; the second interference loop of the first interference mode comprises a paired third interference unit and fourth interference unit; the first interference unit and the fourth interference unit are responsive to an external signal.

4. The method according to claim 2, wherein when the angle between the incoming wave signal direction and the advancing direction of the unmanned aerial vehicle formation is 90 ° to 180 ° or 0 ° to-90 °, the pairing of the interference units is a second interference pattern, two unmanned aerial vehicles on the diagonal line as the advancing direction are respectively used as a first interference unit and a fourth interference unit, and the diagonal line is used as a dividing line, and the interference unit closest to the incoming wave signal and the interference unit on the same side as the diagonal line are paired; the first interference loop of the second interference mode comprises a first interference unit and a third interference unit which are paired; the second interference loop of the second interference mode comprises a second interference unit and a fourth interference unit which are matched; the first interference unit and the fourth interference unit are responsive to an external signal.

5. A method according to claim 3, wherein the first interference mode is a mode of operation:

the signal received by the first interference unit is transmitted to the second interference unit after being modulated by amplitude gain and phase offset, and then transmitted by the second interference unit; the signal received by the second interference unit is directly forwarded to the first interference unit and then transmitted by the first interference unit; the signal received by the third interference unit is modulated by amplitude gain and phase offset and then forwarded to a fourth interference unit, and then transmitted by the fourth interference unit; and the signal received by the fourth interference unit is directly forwarded to the third interference unit and then transmitted by the third interference unit.

6. The method of claim 4, wherein the second interference mode is a mode of operation:

the signal received by the first interference unit is transmitted to the third interference unit after being modulated by amplitude gain and phase offset, and then transmitted by the third interference unit; the signal received by the third interference unit is directly forwarded to the first interference unit and then transmitted by the first interference unit; the signal received by the second interference unit is modulated by amplitude gain and phase offset and then forwarded to a fourth interference unit, and then transmitted by the fourth interference unit; and the signal received by the fourth interference unit is directly forwarded to the second interference unit and then transmitted by the second interference unit.

7. The method of claim 1, wherein the method of capturing the range gate is:

increasing the amplitude difference in the interference modulation direction to increase the sum channel echo of the monopulse radar to capture the range gate; the interference modulation direction is the transmission direction after the amplitude and phase modulation of the received signal in the interference loop.

8. The method of claim 1, wherein increasing the angular error after the target echo moves out of the range gate is by:

modulating the amplitude gains of the two interference loops to enable the self-adaptive multi-loop reverse cross eye interference to obtain high cross eye gain, and further increasing the angle measurement error.

9. The method according to claim 1, wherein the method for adjusting the interference-to-signal ratio is as follows: and obtaining higher interference-signal ratio by mismatching the interference loop amplitude ratio of the interference loop with the interference loop phase difference.

10. The method of claim 1, wherein the interference-to-signal ratio is greater than 20dB.