A deception jamming method and system for DBS mode of seeker based on DRFM

Abstract

This invention relates to a DRFM-based method and system for deceiving and jamming a seeker in DBS mode. The method includes real-time frame reception of radar seeker signals in the antenna coverage direction and transmission of threat seeker velocity and position information. After confirming the threat signal, DRFM processing and high-speed sampling are performed. The radar parameters of the signal are obtained by analyzing and calculating the time and frequency domains. The delay and Doppler parameters of the jamming signal are calculated in conjunction with the velocity and position information. The jamming signal is then modulated and transmitted. The enemy's velocity and position information are continuously updated, and the delay parameters are recalculated to adjust the jamming signal. Different jamming modes are selected based on the threat assessment trajectory to deceive the enemy. This invention can rapidly process transmissions, generate realistic false targets in the DBS image, and guide the false targets to fall within a predetermined deflection range, achieving deceptive jamming of the seeker's DBS mode imaging search and completing self-defense jamming protection for protected targets.

Description

Technical Field

[0001] The present invention relates to the field of radar countermeasure technology, and in particular to a deception jamming method and system for a seeker DBS mode based on DRFM. Background Art

[0002] Doppler beam sharpening (DBS) technology is one of the widely used high-resolution radar imaging technologies. Compared with high-resolution imaging modes such as SAR, it has the advantages of low computational load, good real-time performance, and wide imaging viewing angle, and plays an important role in battlefield reconnaissance and other fields. DBS technology can be applied to long-range target area imaging search mode, and is a hot topic in the guidance field, especially in various types of anti-ship seekers.

[0003] Existing interference against the DBS mode of radar seeker usually adopts noise suppression interference. Suppression interference can reduce the search imaging quality of radar seeker, but cannot achieve control of missile flight trajectory. Radar seeker can still rely on binding data and inertia to fly to the target area or switch to other tracking modes; other feasible interference means are conventional forwarding deception interference and two-dimensional imaging interference of SAR radar; frequency modulation and other means of forwarding deception interference are easily filtered out by the Doppler filter in DBS sub-aperture processing and become ineffective, and the two-dimensional deception interference method for SAR radar usually requires large computing resources and has poor real-time performance, and its application in the field of seeker interference with a short working window is limited. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a DRFM-based seeker DBS mode deception jamming method to solve the defects of the existing interference for the radar seeker DBS mode.

[0005] The object of the present invention is achieved by the following technical solution: a deception jamming method of a seeker DBS mode based on DRFM, the deception jamming method comprising:

[0006] S1, receive the radar seeker signal in the antenna coverage direction in real-time frames, and send the threat seeker speed and position information after confirming the threat warning;

[0007] S2. After confirming the threat signal, DRFM processing is performed, the received threat signal is sampled at high speed, the radar parameters of the signal are obtained by analyzing and calculating the time domain and frequency domain of the cached signal, and the delay parameters and Doppler parameters of the interference signal are calculated in combination with the speed and position information, the interference signal is modulated and the modulated interference signal is transmitted;

[0008] S3. Continuously update the enemy's speed and position information, and recalculate the delay parameters to adjust the interference signal, form the enemy's threat assessment track, and select different interference modes according to the threat assessment track to interfere and deceive the enemy.

[0009] The delay parameter and Doppler parameter of the interference signal calculated by combining the speed and position information include:

[0010] Set the seeker transmission signal to S(t) and the first jammer deployment position to (R 0 , A 0 ), the seeker threat speed is V, and the jamming signal is obtained Where c is the speed of light, is the echo phase component of the coordinate position, α is the two-way attenuation factor, j is an imaginary number, f c is the signal frequency, t is the time;

[0011] Through narrowband approximation, the interference signal is made to be close to the ideal false target (R 0 +ΔR,A 0 +ΔA) is equal, and the delay parameter is obtained and Doppler parameters Where ΔD is the ideal decoy point relative to the first jammer (R 0 , A 0 ) position, ΔR and ΔA represent the distance between the ideal false target and the first jammer (R 0 , A 0 )The distance between the horizontal and vertical coordinates of the position.

[0012] The modulation of the interference signal comprises: modulating the interference signal and the Doppler frequency shift term exp(-j2πf c γt) and delay it by the delay parameter T j Then an interference signal is sent.

[0013] The continuously updating of the enemy's speed and position information, and recalculating the delay parameters to adjust the jamming signal, forming the enemy's threat assessment track, and selecting different jamming modes according to the threat assessment track to jam and deceive the enemy include:

[0014] Continuously update the enemy's speed and position information and adjust the jamming signal, and synchronously store the real-time updated parameter data to form an enemy threat assessment track;

[0015] Using the azimuth distance difference and range distance difference of the enemy relative to ours as coordinate axes, calculate the deviation angle of the current flight track relative to the jammer's position;

[0016] When the angle between the enemy's track and the line connecting the missile and the target is assessed to be less than the preset threshold angle, it is considered that the enemy's seeker has switched from DBS mode to guidance mode, and our side switches to other interference modes until the threat ends.

[0017] The deception interference method also includes receiving the speed and position information of the threat target transmitted by the commander, and inputting the decoy range and speed and position error parameters. This step is performed before step S1.

[0018] It includes an upper-level command and control unit, a display and control device, an integrated frequency conversion unit, a signal processing unit and a power supply unit; the upper-level command and control unit is used to receive the speed and position information of the threat target transmitted by the commander; the display and control unit is used to input the decoy range and speed and position error parameters, and simultaneously monitor the radar parameters of the seeker of the reconnaissance threat party; the integrated frequency conversion unit is used to convert the effective working frequency band to the digital baseband up and down; the signal processing unit is used for signal sampling and reception, digital radio frequency storage, and interference calculation; the power supply unit is used to provide power supply for the entire system.

[0019] The interference calculation specifically includes obtaining radar parameters of the signal by analyzing and calculating the time domain and frequency domain of the cached signal, calculating the delay parameters and Doppler parameters of the interference signal in combination with the speed and position information, and recalculating the delay parameters to adjust the interference signal based on the updated enemy speed and position information to form an enemy threat assessment track.

[0020] The present invention has the following advantages: a deceptive jamming method for DBS mode of a seeker based on DRFM can quickly process transmission, generate realistic false targets in DBS images, and guide the false targets to fall within a predetermined decoy range, thereby achieving deceptive jamming of the imaging search of DBS mode of the seeker and completing self-defense jamming protection for the protected target. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the system of the present invention;

[0022] Figure 2 It is a schematic diagram of the method flow of the present invention;

[0023] Figure 3 Schematic diagram of interference signal modulation of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application provided below in conjunction with the drawings is not intended to limit the scope of protection of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application. The present invention is further described below in conjunction with the drawings.

[0025] like Figure 1 As shown in the figure, the superior command and control unit is mainly a signal input interface, which receives the speed and position information of the threat target transmitted by the accusing party. The display and control device is an interactive operation interface, which can manually input the decoy range and speed and position error parameters. At the same time, it can synchronously monitor the parameters of the threat seeker radar detected by the system. The transceiver antenna is a group of same-frequency antennas, which are responsible for the system airspace control and RF signal reception and transmission. The integrated frequency conversion unit is mainly for the up and down conversion from the effective working frequency band to the digital baseband. The signal processing unit is mainly responsible for signal sampling, reception, DRFM (digital radio frequency storage), interference calculation and other digital processing functions. The power supply unit is responsible for providing the required voltage for the entire system.

[0026] like Figure 2 As shown in the figure, after the system is powered on, the superior command unit is connected, and the operator manually inputs the intended decoy area (rectangular area centered on the jammer) through the display and control system, and selects the command accuracy (error percentage). After the settings are completed, the autonomous workflow can be entered, and the radar seeker signal in the antenna coverage direction is continuously detected and received. After the threat alarm is confirmed, the command system continuously sends the speed and position information of the threatening missile. After the jammer confirms the threat signal, it is transferred to DRFM processing, and the received threat signal is sampled at high speed, and the digitized I, Q signal is stored in RAM. The radar parameters of the signal (including signal form, frequency modulation type, pulse repetition period, pulse width, etc.) are calculated by analyzing the time and frequency domains of the cached digital signal and reported to the display and control device for monitoring. At the same time, the delay and Doppler parameters are calculated based on the speed and position information sent by the command system. The parameter calculation method is as follows:

[0027] Assume that the signal transmitted by the seeker is S(t), the propagation speed is the speed of light c, and the location of the system jammer is (R 0 , A 0 ), the threat speed of the seeker is V, let is the echo phase component of the coordinate position (n is the position number), α is the two-way attenuation factor, and the modulated signal is:

[0028]

[0029] Among them, j is an imaginary number, f c is the signal frequency, t is the time, so that the interference signal and (R 0 +ΔR,A 0 +ΔA) is equal to the signal generated by the ideal false target. After using the narrowband approximation, the calculation method of the delay and Doppler parameters can be obtained:

[0030]

[0031] ΔD is the ideal decoy point relative to the jammer (R 0 , A 0 ) position can be calculated from the set ΔR and ΔA.

[0032] Among them, the Doppler modulation parameters are:

[0033]

[0034] According to the above calculation results, the digital signal cached by DRFM is interfered and modulated. The system DBS interference signal modulation process is as follows: Figure 3 As shown: First, the interference signal and the Doppler frequency shift term exp(-j2πf c γt) and then delayed by the delay parameter T j Issued later.

[0035] After the jamming signal is generated, the DBS two-dimensional imaging of the threat party is processed, and its range is deflected by the delay T j The azimuth deviation is introduced by the Doppler frequency shift term exp(-j2πf c γt) is introduced. Ideally, the two parameters are determined by the preset deviation position (R 0 +ΔR,A 0+ΔA) calculation, the threat party's seeker DBS imaging will be generated and the target at the expected position to achieve deception interference. In actual situations, the input information involved in the modulation parameter calculation includes local speed and position information. The DBS mode is usually used for long-range imaging. At this time, the distance between the projectile and the target is much larger than the azimuth distance difference. The ΔA and ΔR in the position information have little effect on the calculation results. The influence of the speed term V is mainly considered. According to the calculated signal expression, when the input speed parameter V is too large, the azimuth distance of the decoy position will be greater than the preset distance. Therefore, the system can consider setting the speed parameter error percentage, usually 1% to 5%. The speed information involved in the calculation can be used for error pre-compensation, and real-time updates are sent according to the command and control system, so that the position of the deception interference image generated in the end is as close to the preset range as possible.

[0036] Furthermore, the enemy speed and position information is continuously updated to adjust the jamming signal. These parameters can be stored synchronously and form an enemy threat assessment track. The enemy's azimuth distance difference and range distance difference relative to ours are used as coordinate axes to calculate the deviation angle of its current flight track relative to the jammer's position. Since the DBS imaging mode requires a large oblique field of view, otherwise the azimuth information of the target position will be lost. Therefore, when the angle between the enemy's track and the missile-target line is too small, it can be considered that the enemy's seeker has switched from the DBS mode to other forward-looking guidance modes. The threshold can be set to 10° based on experience, and the system switches to other jamming modes (such as dense false target forwarding jamming) until the threat ends.

[0037] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A DRFM-based seeker DBS mode deception jamming method, characterized by: The deception interference method comprises: S1, receive the radar seeker signal in the antenna coverage direction in real-time frames, and send the threat seeker speed and position information after confirming the threat warning; S2. After confirming the threat signal, DRFM processing is performed, the received threat signal is sampled at high speed, the radar parameters of the signal are obtained by analyzing and calculating the time domain and frequency domain of the cached signal, and the delay parameters and Doppler parameters of the interference signal are calculated in combination with the speed and position information, the interference signal is modulated and the modulated interference signal is transmitted; S3, continuously update the enemy's speed and position information, and recalculate the delay parameters to adjust the jamming signal, form the enemy's threat assessment track, and select different jamming modes according to the threat assessment track to jam and deceive the enemy; The delay parameter and Doppler parameter of the interference signal calculated by combining the speed and position information include: Set the seeker transmission signal to S(t), the first jammer deployment position to (R0, A0), the seeker threat speed to V, and get the jamming signal Where c is the speed of light, is the echo phase component of the coordinate position, α is the two-way attenuation factor, j is an imaginary number, f c is the signal frequency, t is the time; Through narrowband approximation, the interference signal is made equal to the signal generated at the ideal false target (R0+ΔR, A0+ΔA), and the delay parameter is obtained. and Doppler parameters Among them, ΔD is the distance between the ideal decoy point and the position of the first jammer (R0, A0), and ΔR and ΔA represent the distance between the ideal false target and the horizontal and vertical coordinates of the position of the first jammer (R0, A0), respectively.

2. The method for deceiving and jamming a seeker DBS mode based on DRFM according to claim 1 is characterized in that: The modulation of the interference signal comprises: modulating the interference signal and the Doppler frequency shift term exp(-j2πf c γt) and delay it by the delay parameter T j Then an interference signal is sent.

3. The method for deceiving and jamming the DBS mode of a seeker based on DRFM according to claim 1 is characterized in that: The continuously updating of the enemy's speed and position information, and recalculating the delay parameters to adjust the jamming signal, forming the enemy's threat assessment track, and selecting different jamming modes according to the threat assessment track to jam and deceive the enemy include: Continuously update the enemy's speed and position information and adjust the jamming signal, and synchronously store the real-time updated parameter data to form an enemy threat assessment track; Using the azimuth distance difference and range distance difference of the enemy relative to ours as coordinate axes, calculate the deviation angle of the current flight track relative to the jammer's position; When the angle between the enemy's track and the line connecting the missile and the target is assessed to be less than the preset threshold angle, it is considered that the enemy's seeker has switched from DBS mode to guidance mode, and our side switches to other interference modes until the threat ends.

4. A DRFM-based seeker DBS mode deception jamming method according to any one of claims 1 to 3, characterized in that: The deception interference method also includes receiving the speed and position information of the threat target transmitted by the commander, and inputting the decoy range and speed and position error parameters. This step is performed before step S1.

5. A DRFM-based seeker DBS mode deception jamming system, characterized by: It includes an upper-level command unit, a display and control device, an integrated frequency conversion unit, a signal processing unit and a power supply unit; the upper-level command unit is used to receive the speed and position information of the threat target transmitted by the commander; the display and control device is used to input the decoy range and speed and position error parameters, and simultaneously monitor the radar parameters of the seeker of the reconnaissance threat party; the integrated frequency conversion unit is used to convert the effective working frequency band to the digital baseband up and down; the signal processing unit is used for signal sampling and reception, digital radio frequency storage, and interference calculation; the power supply unit is used to provide power supply for the entire system; The interference calculation specifically includes obtaining radar parameters of the signal by analyzing and calculating the time domain and frequency domain of the cached signal, calculating the delay parameters and Doppler parameters of the interference signal in combination with the speed and position information, and recalculating the delay parameters to adjust the interference signal according to the updated enemy speed and position information to form an enemy threat assessment track; The delay parameter and Doppler parameter of the interference signal calculated by combining the speed and position information include: Set the seeker transmission signal to S(t), the first jammer deployment position to (R0, A0), the seeker threat speed to V, and get the jamming signal Where c is the speed of light, is the echo phase component of the coordinate position, α is the two-way attenuation factor, j is an imaginary number, f c is the signal frequency, t is the time; Through narrowband approximation, the interference signal is made equal to the signal generated at the ideal false target (R0+ΔR, A0+ΔA), and the delay parameter is obtained. and Doppler parameters Among them, ΔD is the distance between the ideal decoy point and the position of the first jammer (R0, A0), and ΔR and ΔA represent the distance between the ideal false target and the horizontal and vertical coordinates of the position of the first jammer (R0, A0), respectively.

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