Multi-pulse radar detection system and method for resisting harmonic deception jamming

Abstract

The invention provides a multi-pulse radar detection system and method for resisting harmonic deception jamming, and the method comprises the steps: transmitting pulse signals with a plurality of frequency modulation slopes through differential setting, and carrying out the pulse compression of received waves; according to the characteristic that the position of a real target is fixed and the position of a false target is shifted during pulse compression processing of radar signals with different parameters, the purposes of energy accumulation at the real target and false peak energy elimination at the false target are achieved by analyzing the time-domain characteristics after pulse compression processing of the signals and performing combined processing. According to the method, additional auxiliary judgment is not needed, self-adaptive processing capacity is achieved for position judgment and energy elimination of all pseudo peaks, meanwhile, simple calculation modes such as query, addition and subtraction are mainly adopted in the algorithm, and the method has the advantage of being small in calculation amount.

Description

Technical Field

[0001] The present invention relates to the field of electronic countermeasure technology, and in particular to a multi-pulse radar detection system and method that is resistant to harmonic deception interference. Background Art

[0002] Radar jamming is a key research area in modern electronic countermeasures, primarily categorized as suppressive jamming and agile jamming. Suppressive jamming primarily blocks the radar system's receiver by generating a co-frequency noise jamming signal and forwarding it at high power, rendering it ineffective for detection. Existing linear frequency modulation radars utilize a combination of waveform design techniques for transmitting signals with intra-pulse or inter-pulse coherence to suppress jamming signals that do not match the radar's transmit waveform, significantly improving their ability to resist suppressive jamming.

[0003] Deceptive jamming is an effective method for countering linear frequency modulation (LFM) radars. By precisely mimicking the radar's transmitted signal, it ensures that the jamming signal entering the radar receiver achieves the same coherent processing gain as the true target echo, thereby creating a false target. Existing smart jamming technologies primarily implement intermittent store-and-forward jamming based on digital radio frequency memory (DRF) and time-modulated jamming (TMJ). Their mathematical principles are essentially the same: by creating energy discontinuities or phase shifts in the received radar detection signal in the time domain, harmonics are generated in the frequency domain. Properly setting the harmonic parameters can cause the LFM signal's harmonics to overlap with the original signal in the time-frequency domain. This characteristic, after pulse compression processing, produces energy peaks at a certain time delay from the original target, known as pseudo-peaks.

[0004] Patent document CN116203515A discloses a microwave radar power limiter reflected harmonic detection system and method. This solution solves the problem that the vector network cannot test the power limiter reflected harmonics under high power conditions, and therefore does not know the performance of the filter under high power conditions, and cannot adjust the harmonic suppression filter. Summary of the Invention

[0005] In view of the defects in the prior art, the purpose of the present invention is to provide a multi-pulse radar detection system and method that is resistant to harmonic deceptive interference.

[0006] According to the present invention, a multi-pulse radar detection system resistant to harmonic deception interference is provided, comprising:

[0007] Antenna front-end module: It serves as the electromagnetic wave signal receiving end and is connected to the duplexer module. It consists of multiple antenna units and is used to transmit and receive radio signals.

[0008] Duplexer module: cooperates with the RF channel module to realize the radar transmission or reception working mode selection;

[0009] Amplitude and phase control module: includes multiple independent amplitude and phase control devices to control the shape of the array antenna radiation pattern;

[0010] RF channel module: connected to the matched filter module; realizes the functions of amplifying the transmission signal and receiving the echo signal, modulating the baseband signal to the RF signal for transmission, and down-converting the RF signal to the baseband signal;

[0011] Digital control module: connected to the amplitude and phase control module to control the working status of the amplitude and phase control module, duplexer module and signal processing module;

[0012] Matched filter module: connected to the signal storage module, performs matched filtering on the echo signal;

[0013] Signal storage module: connected to the multi-pulse analysis and synthesis module, storing the time domain information of pulse signals with multiple frequency modulation slopes after pulse compression;

[0014] Signal processing module: includes a linear frequency modulation signal generation module and a multi-pulse analysis and synthesis module, which generates the transmitted linear frequency modulation signal, analyzes the time domain characteristics of each signal after pulse compression processing and combines them for processing, reduces the pseudo-peak energy introduced by deceptive interference, and determines the true target position.

[0015] Preferably, in the antenna front-end module: it is used to radiate pulse signals into space and receive echo signals of the target;

[0016] In the duplexer module:

[0017] When the radar system is switched to transmit mode, a linear frequency modulation pulse signal with a frequency modulation slope of μ1 is transmitted.

[0018]

[0019] Where, f0 is the carrier frequency of the echo signal;

[0020] Then, the radar system is switched to the receiving mode, and the echo signal of the received signal is subjected to pulse compression processing; the steps are repeated N times, and the repeated steps include switching the radar system to the transmitting mode, transmitting linear frequency modulation pulse signals with different frequency modulation slopes, and performing pulse compression processing on the echo; the frequency modulation slopes of the linear frequency modulation signals transmitted each time are μ1, μ2, …, μ N , each frequency modulation slope μ1, μ2, …, μ N The values ​​are mutually prime,

[0021] Preferably, in the radio frequency channel module:

[0022] The RF channel module includes a power amplifier, a bandpass filter, two mixers, a RF local oscillator, a low-noise amplifier, and a low-pass filter.

[0023] Preferably, in the signal processing module:

[0024] It includes a linear frequency modulation signal generation module and a multi-pulse waveform analysis module, which are used to generate the transmitted linear frequency modulation signal, analyze the time domain characteristics of each signal after pulse compression processing and combine them for processing, reduce the pseudo-peak energy introduced by deceptive interference and determine the true target position.

[0025] According to the present invention, a multi-pulse radar detection method for resisting harmonic deception interference is provided, which uses the multi-pulse radar detection system for resisting harmonic deception interference and performs the following steps:

[0026] Step S1: Complete the pre-processing operation of the signal radiating energy into space. After the signal passes through the duplexer module and the amplitude and phase control module in the RF channel, the antenna front-end module radiates the energy into space.

[0027] Step S2: After the transmission of the linear frequency modulation pulse signal is completed, the echo signal is received by the antenna front-end module, the echo signal is processed into a baseband signal, and the pulse compression processing is performed on it using the matched filter module. The processed signal is stored in the signal storage module;

[0028] Step S3: storing the time domain signal after the pulse compression processing of each transmission signal into the signal storage module;

[0029] Step S4: spanning the time domain signals of the echo signals stored in the signal storage module after pulse compression into a matrix;

[0030] Step S5: Take the maximum value of each column of the matrix to form a new single row vector, add the echo signal pulses after compression processing to obtain a row vector, and make a difference between the row vector of the echo signal pulses after compression and the single row vector to obtain a new vector as the detection signal vector after deception interference.

[0031] Preferably, in step S1:

[0032] When the system is in the transmitting state, the duplexer module switches to the transmitting mode, and the digital control module generates a control signal to configure the weights of the amplitude and phase control module. The signal processing module generates a linear frequency modulation pulse signal with a frequency modulation slope of μ1. The linear frequency modulation pulse signal is modulated to the carrier frequency by the mixer, filtered by the bandpass filter, and then amplified by the power amplifier. After the signal passes through the duplexer module and the amplitude and phase control module in the RF channel in turn, the antenna front-end module radiates the energy into space.

[0033] Preferably, in step S2:

[0034] When the system completes the transmission of the linear frequency modulation pulse signal, the duplexer module switches the system to the receiving mode. After the echo signal is received by the antenna front-end module, the echo signal passes through the amplitude and phase control module, the duplexer module and the low-noise amplifier in sequence, is down-converted by the mixer, and then becomes a baseband signal through a low-pass filter. The matched filter module is used to perform pulse compression processing on it, and the processed signal is stored in the signal storage module.

[0035] Preferably, in step S3:

[0036] Repeat steps S1 and S2 N times, and the linear frequency modulation signal pulse frequency modulation slopes of each transmission are μ1, μ2, ..., μ N , configure the parameters so that each frequency modulation slope μ1, μ2, …, μ N The values ​​are mutually prime, and the time domain signal after the pulse compression processing of each transmitted signal is stored in the signal storage module.

[0037] Preferably, in step S4:

[0038] After the echo signal pulses with mutually prime frequency modulation slope values ​​are compressed, the time domain signals of the echo signal pulses stored in the signal storage module are compressed into a matrix S PC-O :

[0039] S PC-O (θ,t)=[S O1 (θ,t),S O2 (θ,t),...S ON (θ,t)] T

[0040] The row vector S On (θ, t) is the nth frequency modulation slope μ n The result of the pulse compression processing of the transmitted pulse signal echo is expressed as:

[0041]

[0042] Where θ is the incident signal angle, S rn (θ, t) is the echo signal of the nth transmitted signal, is the response function of the nth matched filter, where t0 is the time difference between the signal being transmitted and the echo signal being received, t is the signal instant, and u is the echo signal delay.

[0043] Preferably, in step S5:

[0044] Take the matrix S PC-O The maximum value of each column forms a new single row vector S PC-max , after pulse compression processing of each echo signal, the row vector is obtained by adding them together:

[0045]

[0046] Compress each echo signal pulse and add the row vector S PC-mix With a single row vector S PC-max Do the difference and get the new vector S PC To remove the deceptive interference and detect the signal vector:

[0047] S PC (θ,t)=S PC-mix (θ,t)-S PC-max (θ,t).

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] 1. The present invention addresses the problem of using harmonic signals to cause deceptive interference to linear frequency modulation pulse radars in electronic countermeasures. It differentially sets and transmits pulse signals with multiple frequency modulation slopes and performs pulse compression on the received echoes. It utilizes the characteristics that the real target position is fixed while the false target position is offset during pulse compression processing of radar signals with different parameters. By analyzing the time domain characteristics of each signal after pulse compression processing and combining them for processing, the pseudo-peak energy introduced by deceptive interference is greatly reduced, thereby realizing anti-deceptive interference detection function; it can effectively eliminate pseudo-peak energy and highlight the real target echo signal.

[0050] 2. The present invention has the characteristics of strong anti-interference ability and simple calculation and judgment method, and is suitable for significantly reducing deceptive interference introduced by linear frequency modulation harmonic signals in electronic countermeasures. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0052] Figure 1 The basic structural block diagram of the multi-pulse radar detection method for resisting harmonic deception interference;

[0053] Figure 2 is the time-frequency relationship diagram of the transmitted signal;

[0054] Figure 3 This is the waveform after pulse compression processing of the echo signal superimposed with the interference signal in Example 3;

[0055] Figure 4 Schematic diagram showing the time domain waveform after processing by the anti-interference method in Example 3 and the comparison of the anti-interference effect;

[0056] Figure 5 Schematic diagram of the system of the present invention;

[0057] Among them, 1 is the antenna front-end module; 2 is the amplitude and phase control module; 3 is the duplexer module; 4 is the power amplifier; 5 is the bandpass filter; 6 is the mixer; 7 is the linear frequency modulation signal generation module; 8 is the RF local oscillator; 9 is the low-noise amplifier; 10 is the mixer; 11 is the low-pass filter; 12 is the matching filter module; 13 is the signal storage module; 14 is the multi-pulse analysis and synthesis module; 15 is the digital control module. DETAILED DESCRIPTION

[0058] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0059] Example 1:

[0060] The present invention realizes an enhanced radar anti-deceptive interference detection function. In order to significantly reduce the pseudo-peak energy introduced by deceptive interference and realize the anti-deceptive interference detection function, the present invention discloses a multi-pulse radar detection method that is resistant to harmonic deceptive interference, including an antenna front-end module, a duplexer module, an amplitude and phase control module, a radio frequency channel module, a digital control module, a matching filter module, a signal storage module and a signal processing module, wherein the signal processing module is composed of a linear frequency modulation signal generation module and a multi-pulse analysis and synthesis module. The array antenna front-end module is connected to the duplexer module, the duplexer module is connected to the radio frequency channel module to realize the radar transmission or reception working mode selection, the radio frequency channel module is connected to the matching filter module, the matching filter module is connected to the signal storage module, the signal storage module is connected to the multi-pulse analysis and synthesis module, and the digital control module is respectively connected to the amplitude and phase control module, the matching filter module and the signal processing module.

[0061] According to the present invention, a multi-pulse radar detection method for resisting harmonic deception interference is provided. Figure 1-Figure 5 Shown, including:

[0062] Step S1: Complete the pre-processing operation of the signal radiating energy into space. After the signal passes through the duplexer module and the amplitude and phase control module in the RF channel, the antenna front-end module radiates the energy into space.

[0063] Specifically, in step S1:

[0064] When the system is in the transmitting state, the duplexer module switches to the transmitting mode, and the digital control module generates a control signal to configure the weights of the amplitude and phase control module. The signal processing module generates a linear frequency modulation pulse signal with a frequency modulation slope of μ1. The linear frequency modulation pulse signal is modulated to the carrier frequency by the mixer, filtered by the bandpass filter, and then amplified by the power amplifier. After the signal passes through the duplexer module and the amplitude and phase control module in the RF channel in turn, the antenna front-end module radiates the energy into space.

[0065] Step S2: After the transmission of the linear frequency modulation pulse signal is completed, the echo signal is received by the antenna front-end module, the echo signal is processed into a baseband signal, and the pulse compression processing is performed on it using the matched filter module. The processed signal is stored in the signal storage module;

[0066] Specifically, in step S2:

[0067] When the system completes the transmission of the linear frequency modulation pulse signal, the duplexer module switches the system to the receiving mode. After the echo signal is received by the antenna front-end module, the echo signal passes through the amplitude and phase control module, the duplexer module and the low-noise amplifier in sequence, is down-converted by the mixer, and then becomes a baseband signal through a low-pass filter. The matched filter module is used to perform pulse compression processing on it, and the processed signal is stored in the signal storage module.

[0068] Step S3: storing the time domain signal after the pulse compression processing of each transmission signal into the signal storage module;

[0069] Specifically, in step S3:

[0070] Repeat steps S1 and S2 N times, and the linear frequency modulation signal pulse frequency modulation slopes of each transmission are μ1, μ2, ..., μ N , configure the parameters so that each frequency modulation slope μ1, μ2, …, μ N The values ​​are mutually prime, and the time domain signal after the pulse compression processing of each transmitted signal is stored in the signal storage module.

[0071] Step S4: spanning the time domain signals of the echo signals stored in the signal storage module after pulse compression into a matrix;

[0072] Specifically, in step S4:

[0073] After the echo signal pulses with mutually prime frequency modulation slope values ​​are compressed, the time domain signals of the echo signal pulses stored in the signal storage module are compressed into a matrix S PC-O :

[0074] S PC-O (θ,t)=[S O1 (θ,t),S O2(θ,t),...S ON (θ,t)] T

[0075] The row vector S On (θ, t) is the nth frequency modulation slope μ n The result of the pulse compression processing of the transmitted pulse signal echo is expressed as:

[0076]

[0077] Where θ is the incident signal angle, S rn (θ, t) is the echo signal of the nth transmitted signal, is the response function of the nth matched filter, where t0 is the time difference between the signal being transmitted and the echo signal being received, t is the signal instant, and u is the echo signal delay.

[0078] Step S5: Take the maximum value of each column of the matrix to form a new single row vector, add the echo signal pulses after compression processing to obtain a row vector, and make a difference between the row vector of the echo signal pulses after compression and the single row vector to obtain a new vector as the detection signal vector after deception interference.

[0079] Specifically, in step S5:

[0080] Take the matrix S PC-o The maximum value of each column forms a new single row vector S PC-max , after pulse compression processing of each echo signal, the row vector is obtained by adding them together:

[0081]

[0082] Compress each echo signal pulse and add the row vector S PC-mix With a single row vector S PC-max Do the difference and get the new vector S PC To remove the deceptive interference and detect the signal vector:

[0083] S PC (θ,t)=S PC-mix (θ,t)-S PC-max (θ,t).

[0084] Example 2:

[0085] Example 2 is a preferred example of Example 1 and is used to illustrate the present invention in more detail.

[0086] The present invention also provides a multi-pulse radar detection system that is resistant to harmonic deception interference. The multi-pulse radar detection system that is resistant to harmonic deception interference can be implemented by executing the process steps of the multi-pulse radar detection method that is resistant to harmonic deception interference. That is, those skilled in the art can understand the multi-pulse radar detection method that is resistant to harmonic deception interference as a preferred implementation of the multi-pulse radar detection system that is resistant to harmonic deception interference.

[0087] According to the present invention, a multi-pulse radar detection system resistant to harmonic deception interference is provided, comprising:

[0088] Antenna front-end module: It serves as the electromagnetic wave signal receiving end and is connected to the duplexer module. It consists of multiple antenna units and is used to transmit and receive radio signals.

[0089] Duplexer module: cooperates with the RF channel module to realize the radar transmission or reception working mode selection;

[0090] Amplitude and phase control module: includes multiple independent amplitude and phase control devices to control the shape of the array antenna radiation pattern;

[0091] RF channel module: connected to the matched filter module; realizes the functions of amplifying the transmission signal and receiving the echo signal, modulating the baseband signal to the RF signal for transmission, and down-converting the RF signal to the baseband signal;

[0092] Digital control module: connected to the amplitude and phase control module to control the working status of the amplitude and phase control module, duplexer module and signal processing module;

[0093] Matched filter module: connected to the signal storage module, performs matched filtering on the echo signal;

[0094] Signal storage module: connected to the multi-pulse analysis and synthesis module, storing the time domain information of pulse signals with multiple frequency modulation slopes after pulse compression;

[0095] Signal processing module: includes a linear frequency modulation signal generation module and a multi-pulse analysis and synthesis module, which generates the transmitted linear frequency modulation signal, analyzes the time domain characteristics of each signal after pulse compression processing and combines them for processing, reduces the pseudo-peak energy introduced by deceptive interference, and determines the true target position.

[0096] Specifically, in the antenna front-end module: it is used to radiate pulse signals into space and receive echo signals of the target;

[0097] In the duplexer module:

[0098] When the radar system is switched to transmit mode, a linear frequency modulation pulse signal with a frequency modulation slope of μ1 is transmitted.

[0099]

[0100] Where, f0 is the carrier frequency of the echo signal;

[0101] Then, the radar system is switched to the receiving mode, and the echo signal of the received signal is subjected to pulse compression processing; the steps are repeated N times, and the repeated steps include switching the radar system to the transmitting mode, transmitting linear frequency modulation pulse signals with different frequency modulation slopes, and performing pulse compression processing on the echo; the frequency modulation slopes of the linear frequency modulation signals transmitted each time are μ1, μ2, …, μ N , each frequency modulation slope μ1, μ2, …, μ N The values ​​are mutually prime,

[0102] Specifically, in the radio frequency channel module:

[0103] The RF channel module includes a power amplifier, a bandpass filter, two mixers, a RF local oscillator, a low-noise amplifier, and a low-pass filter.

[0104] Specifically, in the signal processing module:

[0105] It includes a linear frequency modulation signal generation module and a multi-pulse waveform analysis module, which are used to generate the transmitted linear frequency modulation signal, analyze the time domain characteristics of each signal after pulse compression processing and combine them for processing, reduce the pseudo-peak energy introduced by deceptive interference and determine the true target position.

[0106] Example 3:

[0107] Example 3 is a preferred example of Example 1 and is used to illustrate the present invention in more detail.

[0108] The present invention discloses a multi-pulse radar detection method that is resistant to harmonic deception interference. The method differentially sets and transmits pulse signals with multiple frequency modulation slopes and performs pulse compression on the received echoes. The method utilizes the characteristic that the real target position is fixed while the false target position is offset during pulse compression processing of radar signals with different parameters. By analyzing the time domain characteristics of each signal after pulse compression processing and combining them for processing, the method achieves the purpose of energy accumulation at the real target and elimination of pseudo-peak energy at the false target. The method does not require additional auxiliary judgments and has adaptive processing capabilities for the judgment of each pseudo-peak position and energy elimination. At the same time, the algorithm mainly adopts simple calculation methods such as query, addition, and subtraction, which has the advantage of low computational complexity.

[0109] A multi-pulse radar detection method that resists harmonic deception interference is characterized by comprising: an antenna front-end module, a duplexer module, an amplitude and phase control module, a radio frequency channel module, a digital control module, a matching filter module, a signal storage module, and a signal processing module. The array antenna front-end module is connected to the duplexer module as an electromagnetic wave signal receiving end, the duplexer module and the radio frequency channel module realize the radar transmission or reception working mode selection, the radio frequency channel module is connected to the matching filter module, the matching filter module is connected to the signal storage module, the signal storage module is connected to the multi-pulse analysis and synthesis module, and the digital control module is connected to the amplitude and phase control module, wherein

[0110] The antenna front-end module (1) is composed of a plurality of antenna units and is used for transmitting and receiving radio signals;

[0111] The amplitude and phase control module (2) includes a plurality of independent amplitude and phase control devices, which are used to control the shape of the array antenna radiation pattern;

[0112] The duplexer module (3) realizes the switching of the radar transmission or reception working mode;

[0113] The radio frequency channel module includes a power amplifier (4), a bandpass filter (5), a mixer (6) and a mixer (10), a radio frequency local oscillator (8), a low noise amplifier (9), and a low pass filter (11), which can realize functions such as amplifying the transmission signal and receiving the echo signal, modulating the baseband signal to the radio frequency signal for transmission, and down-converting the radio frequency signal to the baseband signal;

[0114] The digital control module (15) is used to control the working states of the amplitude and phase control module, the duplexer module and the signal processing module;

[0115] A matched filter module (12), configured to perform matched filtering on the echo signal;

[0116] The signal storage module (13) is used to store time domain information of pulse signals with multiple frequency modulation slopes after pulse compression;

[0117] The signal processing module includes a linear frequency modulation signal generation module (7) and a multi-pulse analysis and synthesis module (14), which are used to generate a transmitted linear frequency modulation signal, analyze the time domain characteristics of each signal after pulse compression processing, combine and process, reduce the pseudo-peak energy introduced by deceptive interference, and determine the real target position.

[0118] When the duplexer module switches the radar system to the transmission mode, it transmits a linear frequency modulation pulse signal with a frequency modulation slope of μ1.

[0119]

[0120] Where f0 is the carrier frequency of the echo signal, and then the radar system is switched to the receiving mode to receive the echo signal of the signal and perform pulse compression processing. Repeat this step N times, and the frequency modulation slope of the linear frequency modulation signal transmitted each time is μ1, μ2,…, μ N , each frequency modulation slope μ1, μ2, …, μ N The values ​​are coprime.

[0121] The working principle of the detection method is as follows. The system has two operating modes: transmit mode and receive mode. When the system is operating in transmit mode, the digital control module controls the duplexer to select the RF transmit channel and configures the weights of the amplitude and phase control module to radiate a single pulse linear frequency modulation signal into space. The radar system is then switched to receive mode, the echo signal of the received signal is pulse compressed, and its data is stored in the signal storage module. This step is repeated N times, and the frequency modulation slopes of the linear frequency modulation signal transmitted each time are μ1, μ2, …, μ N , each frequency modulation slope μ1, μ2, …, μ N The values ​​are mutually prime. The time domain row vectors of each echo signal in the signal storage module are stretched into a matrix S PC-O , take the matrix S PC-O The maximum value of each column forms a new single row vector S PC-max At the same time, the new row vector S can be obtained by adding the time domain row vectors of each echo signal in the signal storage module PC-mix Utilizing the characteristic that the real target position is fixed while the false target position is offset when the radar signal pulses with different linear frequency modulation slopes are compressed, the echo signal pulses are compressed and then added to form a row vector S. PC-max With a single row vector S PC-max Take the difference to get the new vector S PC ,This vector has the advantage of significantly reducing the energy of the false target and effectively retaining the ,energy of the real target echo, and can achieve the effect of anti-deceptive ,interference.

[0122] like Figure 1 As shown, in the embodiment, the multi-pulse radar detection system for resisting harmonic deception interference consists of an eight-unit antenna array 1, a high-speed RF switch 2, a duplexer 3, a power amplifier 4, a bandpass filter 5, mixers 6 and 10, a RF local oscillator 8, a low-noise amplifier 9, a low-pass filter 11, a matching filter 12, a signal storage module 13, signal processing modules 7 and 14 and a digital control module 15.

[0123] Assume that the carrier frequency of the transmitted linear frequency modulation signal is f0 = 2 GHz, and each pulse signal has the same duration T = 100 μs, but different bandwidths. The bandwidth of signal 1 is B1 = 7.3 MHz, and the frequency modulation slope is μ1 = B1 / T = 0.73 × 10 11The bandwidth of signal 2 is B2 = 3.7 MHz, and the frequency modulation slope is μ2 = B2 / T = 0.37 × 10 11 The bandwidth of signal 3 is B3 = 5.7 MHz, and the frequency modulation slope is μ3 = -B3 / T = -0.57×10 11 The bandwidth of signal 4 is B4 = 4.7 MHz, and the frequency modulation slope is μ4 = -B4 / T = -0.47×10 11 The target's normal azimuth angle relative to the array is θ = 25°, the antenna array element spacing is d = λ / 2 = 15cm, λ = c / f0 is the wavelength of the incident signal, and c is the speed of electromagnetic wave propagation in a vacuum. The time-frequency relationship diagram of each transmitted signal is as follows: Figure 2 As shown in , the signal has an ideal linear relationship in the time-frequency domain.

[0124] After signal 1 is transmitted, the system switches to the receiving state. After the detection signal is received by the other jammer, an interference signal is generated for forwarding. Assuming that the other jammer is a time-modulated forwarding interference, its modulation period is T p =1μs, modulation frequency f p =1MHz, in one modulation cycle, the on-time of each antenna unit is 0.125μs. After the signal is reflected by the target, it is received and modulated by the array. The number of reception cycles of the entire linear frequency modulation echo signal is M=T / T p = 100, the radar system receives the target echo signal and the interference signal of the other party. Repeat this step until all four pulse signals are transmitted and received. Figure 3 Given S PC-mix From the time domain waveform, we can see that the transmitted signal is modulated and forwarded by the jammer and returned together with the real target echo signal. After the radar end performs pulse compression processing on the received signal, multiple energy peak points of false targets appear on the time domain waveform, and the energy of some peak points is higher than the real target echo energy, making it difficult for the system to accurately locate.

[0125] Figure 4 The S after anti-interference processing is given PC The time domain waveform of S PC-mix The time domain waveform is used for comparison. It can be seen that after anti-interference processing, the peak energy of the false target is greatly suppressed, with the lowest suppression value reaching 20dB, effectively highlighting the echo energy at the real target and enhancing the reliability of radar positioning.

[0126] Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, and units provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same functions of the system and its various devices, modules, and units provided by the present invention in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; the devices, modules, and units for implementing various functions can also be considered as both software modules implementing the method and structures within the hardware component.

[0127] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A multi-pulse radar detection system that is resistant to harmonic deception interference, characterized in that: include: Antenna front-end module: It serves as the electromagnetic wave signal receiving end and is connected to the duplexer module. It consists of multiple antenna units and is used to transmit and receive radio signals. Duplexer module: cooperates with the RF channel module to realize the radar transmission or reception working mode selection; Amplitude and phase control module: includes multiple independent amplitude and phase control devices to control the shape of the array antenna radiation pattern; RF channel module: connected to the matched filter module; realizes the functions of amplifying the transmission signal and receiving the echo signal, modulating the baseband signal to the RF signal for transmission, and down-converting the RF signal to the baseband signal; Digital control module: connected to the amplitude and phase control module to control the working status of the amplitude and phase control module, duplexer module and signal processing module; Matched filter module: connected to the signal storage module, performs matched filtering on the echo signal; Signal storage module: connected to the multi-pulse analysis and synthesis module, storing the time domain information of pulse signals with multiple frequency modulation slopes after pulse compression; Signal processing module: includes a linear frequency modulation signal generation module and a multi-pulse analysis and synthesis module, which generates the transmitted linear frequency modulation signal, analyzes the time domain characteristics of each signal after pulse compression processing and combines them for processing, reduces the pseudo-peak energy introduced by deceptive interference, and determines the true target position.

2. The multi-pulse radar detection system for resisting harmonic deception interference according to claim 1 is characterized in that: In the antenna front-end module: used to radiate pulse signals into space and receive echo signals from the target; In the duplexer module: When the radar system is switched to transmit mode, a linear frequency modulation pulse signal with a frequency modulation slope of μ1 is transmitted. Where f0 is the carrier frequency of the echo signal; t is the time; Then, the radar system is switched to the receiving mode, and the echo signal of the received signal is subjected to pulse compression processing; the steps are repeated N times, and the repeated steps include switching the radar system to the transmitting mode, transmitting linear frequency modulation pulse signals with different frequency modulation slopes, and performing pulse compression processing on the echo; the frequency modulation slopes of the linear frequency modulation signals transmitted each time are μ1, μ2, …, μ N , each frequency modulation slope μ1, μ2, …, μ N The values ​​are coprime.

3. The multi-pulse radar detection system for resisting harmonic deception interference according to claim 1 is characterized in that: In the radio frequency channel module: The RF channel module includes a power amplifier, a bandpass filter, two mixers, a RF local oscillator, a low-noise amplifier, and a low-pass filter.

4. The multi-pulse radar detection system for resisting harmonic deception interference according to claim 1 is characterized in that: In the signal processing module: It includes a linear frequency modulation signal generation module and a multi-pulse waveform analysis module, which are used to generate the transmitted linear frequency modulation signal, analyze the time domain characteristics of each signal after pulse compression processing and combine them for processing, reduce the pseudo-peak energy introduced by deceptive interference and determine the true target position.

5. A multi-pulse radar detection method for resisting harmonic deception interference, characterized in that: The multi-pulse radar detection system resistant to harmonic deception interference according to any one of claims 1 to 4 is used, and the execution includes: Step S1: Complete the pre-processing operation of the signal radiating energy into space. After the signal passes through the duplexer module and the amplitude and phase control module in the RF channel, the antenna front-end module radiates the energy into space. Step S2: After the transmission of the linear frequency modulation pulse signal is completed, the echo signal is received by the antenna front-end module, the echo signal is processed into a baseband signal, and the pulse compression processing is performed on it using the matched filter module. The processed signal is stored in the signal storage module; Step S3: storing the time domain signal after the pulse compression processing of each transmission signal into the signal storage module; Step S4: spanning the time domain signals of the echo signals stored in the signal storage module after pulse compression into a matrix; Step S5: Take the maximum value of each column of the matrix to form a new single row vector, add the echo signal pulses after compression processing to obtain a row vector, and make a difference between the row vector of the echo signal pulses after compression and the single row vector to obtain a new vector as the detection signal vector after deception interference.

6. The multi-pulse radar detection method for resisting harmonic deception interference according to claim 5 is characterized in that: In step S1: When the system is in the transmitting state, the duplexer module switches to the transmitting mode, the digital control module generates a control signal to configure the weight of the amplitude and phase control module, and the signal processing module generates a linear frequency modulation pulse signal with a frequency modulation slope of μ1. The linear frequency modulation pulse signal is modulated to the carrier frequency by the mixer, filtered by the bandpass filter, and then amplified by the power amplifier; The signal passes through the duplexer module and the amplitude and phase control module in the RF channel in sequence, and then the antenna front-end module radiates the energy into space.

7. The multi-pulse radar detection method for resisting harmonic deception interference according to claim 5 is characterized in that: In step S2: When the system completes the transmission of the linear frequency modulation pulse signal, the duplexer module switches the system to the receiving mode. After the echo signal is received by the antenna front-end module, the echo signal passes through the amplitude and phase control module, the duplexer module and the low-noise amplifier in sequence, is down-converted by the mixer, and then becomes a baseband signal through a low-pass filter. The matched filter module is used to perform pulse compression processing on it, and the processed signal is stored in the signal storage module.

8. The multi-pulse radar detection method for resisting harmonic deception interference according to claim 5, characterized in that: In step S3: Repeat steps S1 and S2 N times, and the linear frequency modulation signal pulse frequency modulation slopes of each transmission are μ1, μ2, ..., μ N , configure the parameters so that each frequency modulation slope μ1, μ2, …, μ N The values ​​are mutually prime, and the time domain signal after the pulse compression processing of each transmitted signal is stored in the signal storage module.

9. The multi-pulse radar detection method for resisting harmonic deception interference according to claim 5, characterized in that: In step S4: After the echo signal pulses with mutually prime frequency modulation slope values ​​are compressed, the time domain signals of the echo signal pulses stored in the signal storage module are compressed into a matrix S PC-O : The row vector S On (θ, t) is the nth frequency modulation slope μ n The result of the pulse compression processing of the transmitted pulse signal echo is expressed as: Where θ is the incident signal angle, S rn (θ, t) is the echo signal of the nth transmitted signal, is the response function of the nth matched filter, where t0 is the time difference between the signal being transmitted and the echo signal being received, t is the signal instant, and u is the echo signal delay.

10. The multi-pulse radar detection method for resisting harmonic deception interference according to claim 5, characterized in that: In step S5: Take the matrix S PC-O The maximum value of each column forms a new single row vector S PC-max , after pulse compression processing of each echo signal, the row vector is obtained by adding them together: Compress each echo signal pulse and add the row vector S PC-mix With a single row vector S PC-max Do the difference and get the new vector S PC To remove the deceptive interference and detect the signal vector: S PC (θ,t)=S PC-mix (θ,t)-S PC-max (θ,t).

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