Fuse anti-interference method, system and equipment based on random pulse position and frequency agility composite modulation and medium

Abstract

The invention discloses a fuze anti-interference method, system and device based on random pulse position and frequency agility composite modulation and a medium, and the method comprises the steps: carrying out random pulse position and frequency agility composite modulation on a transmitted sub-pulse signal, and setting basic parameters of a fuze transmitted signal; the fuze transmitting end radiates a transmitting signal, the fuze receiving end captures an echo signal r (t), then the echo signal r (t) is sequentially subjected to frequency mixing and filtering processing, and after the processed echo signal r '(t) enters a specified correlator channel, random pulse position correlation operation and frequency agility correlation operation are respectively carried out to obtain a second-stage output signal of the fuze correlator; performing range gate gating and constant false alarm detection on the second-stage output signal of the fuze correlator in sequence until peak pulses near a preset explosion height are continuously detected for multiple times, and then outputting a detonation signal; according to the invention, random pulse position and frequency agility composite modulation are taken as an inner core, series two-stage related processing is taken as a skeleton, continuous cycle detection is taken as insurance, and a dual anti-interference system with both accuracy and robustness is constructed.

Description

Technical Field

[0001] This invention relates to the field of radio fuze anti-interference technology, specifically to an anti-interference method, system, device, and medium based on a composite modulation fuze using random pulse position and frequency agile modulation. Background Technology

[0002] Traditional ultra-wideband (UWB) fuze technology, with its wide spectrum coverage and high range resolution, exhibits significant advantages in complex battlefield environments. However, with the rapid evolution of electromagnetic countermeasures and target stealth technologies, the UWB system has revealed increasingly prominent problems in engineering applications, including high system complexity, sensitivity to multipath effects, and insufficient resistance to dense spectrum interference. These issues make it difficult to meet the multi-dimensional collaborative requirements of modern warfare for fuze systems, demanding low interception rate, strong environmental adaptability, and high reliability. Therefore, improving the anti-jamming capability of UWB fuzes in complex electromagnetic environments has become a core issue that urgently needs to be addressed in radio fuze systems.

[0003] Existing research on anti-interference methods for fuses mainly includes: optimization design of the frequency domain angle of the fuse signal, mainly including two types of technology: frequency agility and spread spectrum. Frequency agility technology enables the signal carrier frequency to jump rapidly within a preset frequency band, which can effectively counter narrowband aiming interference. However, the frequency hopping pattern of frequency agility technology is easily cracked by AI and has low spectrum utilization. Spread spectrum technology mainly widens the signal spectrum to counter interference. For example, the US military's JDAM-ER bomb fuse has an anti-interference gain of ≥20dB. However, its processing gain is limited by the chip rate and its ability to resist broadband noise interference is weak. For the optimization design of the fuze signal in the time domain, there are two main approaches: random pulse position modulation (RPM) and pulse width / amplitude agility. Random pulse position modulation improves its randomness and anti-interception capability by randomly shifting the pulse emission time, but it is less effective under high-power suppression jamming. Pulse width / amplitude agility improves its anti-jamming capability by dynamically adjusting the pulse width or amplitude. For example, the pulse width of the Chinese PL-15E air-to-air missile fuze varies from 50ns to 200ns, but the parameter adjustment range is limited and the anti-jamming dimension is singular. In addition, anti-jamming can also be achieved at the signal processing layer through corresponding algorithms, such as deep learning and reinforcement learning. Adaptive learning can effectively combat some new types of jamming, but this method poses a significant challenge to the high-computing-power chips of the missile platform.

[0004] Dong Erwa (Dong Erwa, Hao Xinhong, Li Ping, et al. Analysis of interference mechanism of new type of fuze [J]. High Power Laser and Particle Beam, 2021, 33(12):59-65.) conducted a relevant analysis on the interference mechanism of new type of fuze. Taking the random pulse position modulation fuze as the research object, the response mechanism under sensitive interference was revealed. The output response characteristics of the correlator of the ultra-wideband fuze receiver were simulated and calculated under the action of radio frequency noise, sinusoidal amplitude modulation, sinusoidal frequency modulation and frequency sweeping sinusoidal amplitude modulation interference signals. The modulation fuze can effectively resist aiming interference, but its ability to resist frequency sweeping interference is weak. Summary of the Invention

[0005] To overcome the shortcomings of the existing technology, the present invention aims to provide an anti-interference method, system, device, and medium for a fuze based on random pulse position and frequency agile composite modulation. The method includes performing random pulse position and frequency agile composite modulation on the transmitting sub-pulse signal and setting the basic parameters of the fuze transmitting signal; the fuze transmitting end radiates the composite-modulated transmitting signal; the fuze receiving end captures the echo signal r(t); the echo signal r(t) is then sequentially mixed and filtered; the processed echo signal r′(t) enters a designated correlator channel, where random pulse position correlation and frequency agile correlation operations are performed respectively to obtain the second-stage output signal u of the fuze correlator. R2 The second-stage output signal u of the fuze correlator R2 The system sequentially performs distance gating and constant false alarm detection until multiple consecutive peak pulses near the preset detonation height are detected, at which point a detonation signal is output. This invention uses random pulse position and agile frequency modulation as its core, two-level correlation processing as its framework, and continuous cyclic detection as a safety measure, thus constructing a dual anti-interference system that combines accuracy and robustness.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An anti-interference method based on a composite modulation fuze using random pulse position and frequency agile modulation includes the following steps:

[0008] Step 1: Perform random pulse position modulation and frequency agile modulation on the transmitting sub-pulse signal, and set the basic parameters of the fuze transmitting signal s(t);

[0009] Step 2: The fuze transmitter radiates the transmitted signal s(t), and the fuze receiver receives the echo signal r(t);

[0010] Step 3: Mix and filter the echo signal r(t) and the fuze's mixing signal in sequence to obtain the echo signal r′(t);

[0011] Step 4: After the echo signal r′(t) enters the designated correlator channel of the fuze, it undergoes random pulse position correlation operation with the fuze's local random pulse position reference signal sref0(t) to obtain the first-stage output signal u of the fuze correlator. R1 ;

[0012] Step 5: The first stage output signal u of the fuse correlator R1 A frequency-agile correlation operation is performed with the local frequency-agile reference signal sref1(t) of the fuze to obtain the second-stage output signal u of the fuze correlator. R2 ;

[0013] Step 6: Output signal u of the second stage of the fuse correlator R2 The process involves sequentially performing distance gate selection and constant false alarm detection. If a spike pulse is detected near the preset detonation height, the detection is successful. The distance of the distance gate is then adjusted to change the frequency of the local frequency-agile reference signal sref1(t) of the fuze. The process then returns to step 2 and continues with steps 2-6 until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output. If no spike pulse is detected near the preset detonation height, the detection fails. The process then returns to step 2 and repeats steps 2-6 until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output.

[0014] Furthermore, step 1 specifically includes:

[0015] Step 1.1: The ultra-narrow pulse generator generates the transmitter sub-pulse signal:

[0016]

[0017] Among them, T p Where t is the pulse width and t is the time.

[0018] Step 1.2: Set the random pulse position modulation parameters of the transmitted sub-pulse signal: modulation coefficient k is 0.3~0.5, code points m=6; set the frequency agile modulation parameters of the transmitted sub-pulse signal: Costas sequence C i = [1,3,4,2,6,5], step frequency interval Δf = 1GHz;

[0019] Step 1.3: Set the basic parameters of the fuze transmission signal s(t): pulse width Tp = 1ns, pulse repetition frequency prf = 5MHz, number of periods N = 20, initial carrier frequency f0 = 22GHz, signal amplitude A = 1, correlation processing period Tr = 4us.

[0020] Furthermore, step 2 specifically includes:

[0021] Step 2.1: The fuze transmitter radiates the emitted signal s(t):

[0022]

[0023] Where j is the imaginary unit, f0 is the starting frequency of the transmitted signal, A is the amplitude of the transmitted signal, N is the number of periods, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. i To obey [0, kT] D A uniformly distributed random variable, f i Let i be the frequency corresponding to the i-th pulse;

[0024] Step 2.2: The fuze receiver receives the echo signal r(t):

[0025]

[0026] Among them, A r Let f be the signal amplitude, τ = 2R(t) / c be the echo delay, R(t) be the distance between the fuze and the target, c be the speed of light, and f be the signal amplitude. d The Doppler frequency that occurs during the rendezvous between the projectile and the target. τ0 = 2R0 / c is the local time delay corresponding to the preset bomb height, R0 is the preset bomb height, and n(t) is the noise and interference signal.

[0027] Furthermore, step 3 specifically includes:

[0028] Step 3.1: Generating a mixing signal with the fuze:

[0029]

[0030] Where N is the number of periods, j is the imaginary unit, and f j The frequency of the signal at the current moment;

[0031] Step 3.2: Mix the echo signal r(t) with the mixing signal to obtain:

[0032]

[0033] Where Ar is the amplitude of the echo signal, N is the number of periods, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. i To obey [0, kT] D The uniformly distributed random variable, τ = 2R(t) / c is the echo delay, R(t) is the distance between the fuze and the target, c is the speed of light, and f is the distance between the fuze and the target. i f is the frequency corresponding to the i-th pulse. d The Doppler frequency that occurs during the rendezvous between the projectile and the target. τ0 = 2R0 / c is the local time delay corresponding to the preset bomb height, R0 is the preset bomb height, and n(t) is the noise and interference signal.f (t) represents the interference signal after mixing;

[0034] Step 3.3: Filter equation (11) to obtain the echo signal r′(t):

[0035]

[0036] Where, Δf=f i -f j n f ′(t) represents the interference signal after mixing and filtering.

[0037] Furthermore, step 4 specifically includes:

[0038] Step 4.1: When Δf = 0 for the echo signal r′(t) in equation (12), the echo signal r′(t) enters the correlator channel specified by the fuze, and at the same time, the fuze generates a local random pulse position reference signal sref0(t):

[0039]

[0040] Where A is the amplitude of the local random pulse position reference signal, N is the number of periods, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. j To obey [0, kT] D A uniformly distributed random variable, τ0=2R0(t) / c is the local time delay corresponding to the preset blast height, R0(t) is the preset blast height, and c is the speed of light;

[0041] Step 4.2: The echo signal r′(t) and the local random pulse position reference signal sref0(t) are subjected to random pulse position correlation operation within one sampling pulse period Tr to obtain the first stage output signal u of the fuze correlator. R1 :

[0042]

[0043] Where AAr is the amplitude of the output signal, X i To obey [0, kT] D A uniformly distributed random variable, τ = 2R(t) / c is the echo delay, R(t) is the distance between the fuze and the target, f d The Doppler frequency that occurs during the rendezvous between the projectile and the target.

[0044] Furthermore, step 5 specifically includes:

[0045] Step 5.1: Generate the local frequency agile reference signal sref1(t) using the fuze:

[0046]

[0047] Where N is the number of periods, j is the imaginary unit, and f j The frequency of the signal at the current moment;

[0048] Step 5.2: First-stage output signal u of the fuze correlator R1 The local frequency-agile reference signal sref1(t) is subjected to frequency-agile correlation operation within one sampling pulse period Tr to obtain the second-stage output signal u of the fuze correlator. R2 :

[0049]

[0050] Where AAr is the amplitude of the output signal, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. i With X j All obey [0, kT] D A uniformly distributed random variable, τ = 2R(t) / c is the echo delay, R(t) is the distance between the fuse and the target, c is the speed of light, τ0 = 2R0(t) / c is the local delay corresponding to the preset detonation height, R0(t) is the preset detonation height, f d f represents the Doppler frequency that may occur during the rendezvous between the projectile and the target. j The frequency of the local frequency-agile reference signal at the current moment.

[0051] An anti-interference system based on a composite modulation fuze using random pulse position and frequency agile modulation includes:

[0052] Signal modulation module: performs random pulse position modulation and frequency agile modulation on the transmitting sub-pulse signal, and sets the basic parameters of the fuze transmitting signal s(t);

[0053] Signal transmitting and receiving module: The fuze transmitter radiates the transmitted signal s(t), and the fuze receiver receives the echo signal r(t);

[0054] Signal preprocessing module: The echo signal r(t) and the fuze's mixing signal are mixed and filtered sequentially to obtain the echo signal r′(t);

[0055] Random pulse position correlation module: After the echo signal r′(t) enters the correlator channel specified by the fuze, it performs random pulse position correlation operation with the fuze's local random pulse position reference signal sref0(t) to obtain the first-stage output signal u of the fuze correlator. R1 ;

[0056] Frequency agile related module: Fuze correlator first stage output signal u R1A frequency-agile correlation operation is performed with the local frequency-agile reference signal sref1(t) of the fuze to obtain the second-stage output signal u of the fuze correlator. R2 ;

[0057] Loop detection module: for the second-stage output signal u of the fuze correlator R2 The system sequentially performs distance gating and constant false alarm rate (CFAR) detection. If a spike pulse near the preset detonation height is detected, the detection is successful. The distance of the distance gate is then adjusted to change the frequency of the local frequency-agile reference signal sref1(t) of the fuze. The system then returns to the signal transmission and reception module and continues to execute the signal transmission and reception module, signal preprocessing module, random pulse position correlation module, frequency agile correlation module, and cyclic detection module sequentially until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output. If no spike pulse near the preset detonation height is detected, the detection fails. The system then returns to the signal transmission and reception module and repeats the signal transmission and reception module, signal preprocessing module, random pulse position correlation module, frequency agile correlation module, and cyclic detection module sequentially until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output.

[0058] An anti-interference device based on a composite modulation fuze using random pulse position and frequency agile modulation includes:

[0059] Memory: Used to store computer programs implementing the above-described method for anti-interference using a composite modulation fuze based on random pulse position and agile frequency conversion;

[0060] Processor: Used to implement the above-described method for anti-interference using a composite modulation fuze based on random pulse position and agile frequency conversion when executing the computer program.

[0061] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned anti-interference method based on a random pulse position and frequency-agile composite modulation fuze.

[0062] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0063] 1. In step 1 of this invention, when performing random pulse position modulation and frequency agile modulation on the transmitting sub-pulse signal, random pulse position modulation can remove the periodicity in the time domain, making the signal spectrum highly random, while frequency agile modulation can remove the periodicity in the frequency domain, making the signal frequency point change randomly. By using the composite modulation technology of random pulse position and frequency agile modulation, the time and frequency domains of the lead-transmitted signal are both de-periodized, improving the signal's anti-interception and anti-interference capabilities. Compared with the limitations of existing single modulation techniques that can only combat specific interference, the composite modulation technology of this invention can effectively combat both aiming interference and frequency sweeping interference simultaneously, thus having a greater probability of correct fuse detonation.

[0064] 2. In step 4 of this invention, after the echo signal r′(t) enters the designated correlator channel of the fuze, when performing random pulse position correlation calculation with the fuze's local random pulse position reference signal sref0(t), the problem of conventional fixed repetitive periodic pulse fuzes being easily detected and intercepted by enemy jammers is solved through random pulse position correlation calculation. This achieves high-precision range information and effective countermeasures against aiming jamming, and features the ability to disrupt the synchronization of jamming signals and significantly improve the fuze's anti-interception capability. In step 5 of this invention, the first-stage output signal u of the fuze correlator... R1 Frequency agile correlation operations are performed with the local frequency agile reference signal sref1(t) of the fuze. Through these operations, the problem of severe signal-to-noise ratio degradation of the receiver caused by enemy-initiated targeting or frequency-sweeping jamming is solved, and high-precision velocity information is obtained. This makes it difficult for enemy jammers to accurately capture the current signal frequency, significantly improving the fuze's ability to counter frequency-sweeping jamming. Through the cascaded processing of random pulse position correlation and frequency agile correlation, most jamming signals can be filtered out. In complex and strong electronic warfare environments, the true distance and velocity information of the target can be extracted stably and reliably, achieving high-precision proximity control. This approach comprehensively utilizes the dual randomness of the time and frequency domains to form a multi-dimensional anti-jamming barrier, greatly enhancing the fuze's anti-jamming and anti-interception capabilities.

[0065] 3. In step 6 of the present invention, the output signal u of the second stage of the fuze correlator is... R2 When performing distance gate selection and constant false alarm detection in sequence, the detonation signal is output after 3-5 consecutive successful detections. Through multiple detection and verification, the probability of false alarms caused by sudden noise, occasional deceptive interference and environmental clutter is significantly reduced. It effectively filters random fluctuation noise and instantaneous aiming interference signals, and enhances the anti-interference capability of the fuze.

[0066] In summary, this invention, through a full-link innovation of "signal modulation-processing architecture-decision mechanism," uses time-frequency dual randomness as its core, two-level serial correlation processing as its framework, and continuous cyclic detection as a safeguard, to construct a dual anti-interference system that combines accuracy and robustness. Compared with existing technologies, this invention can effectively suppress aiming interference and frequency sweeping interference, significantly improving the fuze's anti-ambiguity, anti-interception, and anti-interference capabilities. Attached Figure Description

[0067] Figure 1 This is a flowchart of an anti-interference method based on a composite modulation fuze using random pulse position and agile frequency conversion.

[0068] Figure 2 The time-domain waveform of a random pulse position and frequency-agile composite modulation fuze.

[0069] Figure 3The spectrum diagrams are for traditional ultra-wideband fuses, random pulse position fuses, frequency agile fuses, and composite modulation fuses of random pulse position and frequency agile modes; among them, Figure 3 (a) in the diagram is the spectrum of a traditional ultra-wideband fuze; Figure 3 (b) in the diagram is the spectrum of a random pulse position fuze; Figure 3 (c) in the diagram is the spectrum of the frequency agile fuze; Figure 3 (d) in the figure is the spectrum of the random pulse position and frequency agile composite modulation fuze.

[0070] Figure 4 It is a fuzzy function diagram of traditional ultra-wideband fuses, random pulse position fuses, frequency agile fuses, and composite modulation fuses of random pulse position and frequency agile modes; among them, Figure 4 (a) in the figure is the fuzzy function diagram of a traditional ultra-wideband fuze; Figure 4 (b) in the figure is the fuzzy function diagram of the random pulse position fuze; Figure 4 (c) in the figure is the fuzzy function diagram of the frequency agile fuze; Figure 4 (d) in the figure is the fuzzy function diagram of the random pulse position and frequency agile composite modulation fuze.

[0071] Figure 5 A comparative graph showing the change in the correct detonation probability as a function of the input signal-to-interference ratio for traditional ultra-wideband fuses, random pulse position fuses, frequency agile fuses, and composite modulation fuses of random pulse position and frequency agile modulation under sinusoidal aiming suppression interference.

[0072] Figure 6 This is a comparison chart showing the correct detonation probability of traditional ultra-wideband fuses, random pulse position fuses, frequency agile fuses, and composite modulation fuses of random pulse position and frequency agile under sinusoidal frequency sweep interference as a function of the input signal-to-interference ratio. Detailed Implementation

[0073] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0074] See Figure 1 An anti-interference method based on a composite modulation fuze using random pulse position and frequency agile modulation includes the following steps:

[0075] Step 1: Perform random pulse position modulation and frequency agile modulation on the transmitting sub-pulse signal, and set the basic parameters of the fuze transmitting signal s(t);

[0076] Step 1 specifically includes:

[0077] Step 1.1: The ultra-narrow pulse generator generates the transmitter sub-pulse signal:

[0078]

[0079] Among them, T p Where t is the pulse width and t is the time.

[0080] Step 1.2: Set the random pulse position modulation parameters of the transmitted sub-pulse signal: modulation coefficient k is 0.3~0.5, code points m=6; set the frequency agile modulation parameters of the transmitted sub-pulse signal: Costas sequence C i = [1,3,4,2,6,5], step frequency interval Δf = 1GHz; the modulation coefficient k in this embodiment is set to 0.3;

[0081] Step 1.3: Set the basic parameters of the fuze transmission signal s(t): pulse width Tp = 1ns, pulse repetition frequency prf = 5MHz, number of periods N = 20, initial carrier frequency f0 = 22GHz, signal amplitude A = 1, correlation processing period Tr = 4us.

[0082] Step 2: The fuze transmitter radiates the transmitted signal s(t), and the fuze receiver receives the echo signal r(t);

[0083] Step 2 specifically includes:

[0084] Step 2.1: The fuze transmitter radiates the emitted signal s(t):

[0085]

[0086] Where j is the imaginary unit, f0 is the starting frequency of the transmitted signal, A is the amplitude of the transmitted signal, N is the number of periods, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. i To obey [0, kT] D A uniformly distributed random variable, f i The frequency corresponding to the i-th pulse;

[0087] After the random pulse position and frequency agile composite modulation in step 1, the random characteristics and high-resolution theoretical verification of the emitted signal s(t) radiated from the fuze transmitter are performed:

[0088] By performing a Fourier transform on the transmitted signal s(t) in equation (2) and utilizing the properties of linear superposition, time shift, and frequency shift, we can obtain:

[0089]

[0090] Where W(f) is the spectrum function of the second derivative of the Gaussian function. C i For the Costas encoded sequence, Δf = f i -f j f j The frequency of the signal at the current moment;

[0091] As can be seen from equation (3), the spectrum of the transmitted signal s(t) after random pulse position and frequency agile composite modulation is formed by randomized shifting and superposition of the spectrum of the second-order Gaussian derivative function. The spectral interval is due to the random variable X i The introduction of makes it randomized, which in turn gives the fuze spectrum function a strong random characteristic.

[0092] According to the definition of the fuzzy function, the fuzzy function of the transmitted signal s(t) after random pulse position and frequency agile composite modulation is:

[0093]

[0094] Where τ = 2R(t) / c is the echo delay, R(t) is the distance between the fuze and the target, c is the speed of light, and f is the distance between the fuze and the target. d Let E be the Doppler frequency that occurs during the rendezvous between the projectile and the target, E be the energy of the single pulse of the transmitted signal, u(t) be the complex envelope of the transmitted signal, u*(t) be the conjugate signal of u(t), and C be the frequency of the projectile. j For the Costas encoded sequence, Δf = f i -f j ;

[0095]

[0096] When i = j, let t - iT D -X i =t′, we can get:

[0097]

[0098] Where w(t) is the transmitted sub-pulse signal, w*(t) is the conjugate signal of the transmitted sub-pulse signal, and f d The Doppler frequency that occurs during the rendezvous between the projectile and the target.

[0099] When i = j, because X i With X j Independent of each other, I ij =0, then:

[0100]

[0101] Where k is the modulation coefficient.

[0102] Assuming the blur bands do not overlap, the modulus value can be obtained as follows:

[0103] |χ(τ,f d )|=|A| 2 ·|sinc(f d kT D ,fd T D )|·|χ w (τ,f d (8)

[0104] As can be seen from equation (8), the ultra-wideband characteristics of the second-order derivative of Gaussian function dominate the time delay resolution of the transmitted signal s(t) after random pulse position and frequency agile modulation, and further suppress the range sidelobe through polynomial phase; while the two-dimensional sinc function controls the Doppler resolution through random time offset and pulse repetition period, and the product form of the ambiguity function further compresses the main lobe and suppresses the sidelobe, which can realize high-resolution detection of the time delay-Doppler plane.

[0105] Step 2.2: The fuze receiver receives the echo signal r(t):

[0106]

[0107] Among them, A r Let f be the signal amplitude, τ = 2R(t) / c be the echo delay, R(t) be the distance between the fuze and the target, c be the speed of light, and f be the signal amplitude. d The Doppler frequency that occurs during the rendezvous between the projectile and the target. τ0 = 2R0 / c is the local time delay corresponding to the preset bomb height, R0 is the preset bomb height, and n(t) is the noise and interference signal.

[0108] Step 3: Mix and filter the echo signal r(t) and the fuze's mixing signal in sequence to obtain the echo signal r′(t);

[0109] Step 3 specifically includes:

[0110] Step 3.1: Generating a mixing signal with the fuze:

[0111]

[0112] Where N is the number of periods, j is the imaginary unit, and f j The frequency of the signal at the current moment;

[0113] Step 3.2: Mix the echo signal r(t) with the mixing signal to obtain:

[0114]

[0115] Where Ar is the amplitude of the echo signal, N is the number of periods, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. i To obey [0, kT] DThe uniformly distributed random variable, τ = 2R(t) / c is the echo delay, R(t) is the distance between the fuze and the target, c is the speed of light, and f is the distance between the fuze and the target. i f is the frequency corresponding to the i-th pulse. d The Doppler frequency that occurs during the rendezvous between the projectile and the target. τ0 = 2R0 / c is the local time delay corresponding to the preset bomb height, R0 is the preset bomb height, and n(t) is the noise and interference signal. f (t) represents the interference signal after mixing;

[0116] Step 3.3: Filter equation (11) to obtain the echo signal r′(t):

[0117]

[0118] Where, Δf=f i -f j n f ′(t) represents the interference signal after mixing and filtering.

[0119] Step 4: After the echo signal r′(t) enters the designated correlator channel of the fuze, it undergoes random pulse position correlation operation with the fuze's local random pulse position reference signal sref0(t) to obtain the first-stage output signal u of the fuze correlator. R1 ;

[0120] Step 4 specifically includes:

[0121] Step 4.1: When Δf = 0 for the echo signal r′(t) in equation (12), the echo signal r′(t) enters the correlator channel specified by the fuze, and at the same time, the fuze generates a local random pulse position reference signal sref0(t):

[0122]

[0123] Where A is the amplitude of the local random pulse position reference signal, N is the number of periods, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. j To obey [0, kT] D A uniformly distributed random variable, τ0=2R0(t) / c is the local time delay corresponding to the preset blast height, R0(t) is the preset blast height, and c is the speed of light;

[0124] Step 4.2: The echo signal r′(t) and the local random pulse position reference signal sref0(t) are subjected to random pulse position correlation operation within one sampling pulse period Tr to obtain the first stage output signal u of the fuze correlator. R1 :

[0125]

[0126] Where AAr is the amplitude of the output signal, X i To obey [0, kT] D A uniformly distributed random variable, τ = 2R(t) / c is the echo delay, R(t) is the distance between the fuze and the target, f d The Doppler frequency that occurs during the rendezvous between the projectile and the target.

[0127] Step 5: The first stage output signal u of the fuse correlator R1 A frequency-agile correlation operation is performed with the local frequency-agile reference signal sref1(t) of the fuze to obtain the second-stage output signal u of the fuze correlator. R2 ;

[0128] Step 5 specifically includes:

[0129] Step 5.1: Generate the local frequency agile reference signal sref1(t) using the fuze:

[0130]

[0131] Where N is the number of periods, j is the imaginary unit, and f j The frequency of the signal at the current moment;

[0132] Step 5.2: First-stage output signal u of the fuze correlator R1 The local frequency-agile reference signal sref1(t) is subjected to frequency-agile correlation operation within one sampling pulse period Tr to obtain the second-stage output signal u of the fuze correlator. R2 :

[0133]

[0134] Where AAr is the amplitude of the output signal, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. i With X j All obey [0, kT] D A uniformly distributed random variable, τ = 2R(t) / c is the echo delay, R(t) is the distance between the fuse and the target, c is the speed of light, τ0 = 2R0(t) / c is the local delay corresponding to the preset detonation height, R0(t) is the preset detonation height, f d f represents the Doppler frequency that may occur during the rendezvous between the projectile and the target. j The frequency of the local frequency-agile reference signal at the current moment.

[0135] Step 6: Output signal u of the second stage of the fuse correlator R2The process involves sequentially performing distance gate selection and constant false alarm detection. If a spike pulse is detected near the preset detonation height, the detection is successful. The distance of the distance gate is then adjusted to change the frequency of the local frequency-agile reference signal sref1(t) of the fuze. The process then returns to step 2 and continues with steps 2-6 until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output. If no spike pulse is detected near the preset detonation height, the detection fails. The process then returns to step 2 and repeats steps 2-6 until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output.

[0136] The distance gating method involves opening windows within a preset detonation height at a distance resolution on both the left and right, focusing only on the second-stage output signal of the fuze correlator within this range. The constant false alarm rate (CFAR) detection method involves discretely sampling the second-stage output signal of the fuze correlator within the distance gate and setting a detection threshold, which is dynamically adjusted according to the actual situation to detect spike pulses within the distance gate. Through "space-energy" dual-dimensional filtering, using dynamic window focusing and threshold decision, residual interference is accurately eliminated while ensuring target detection accuracy, providing high-confidence input for subsequent continuous detection and reducing the probability of false detonation of the fuze.

[0137] An anti-interference system based on a composite modulation fuze using random pulse position and frequency agile modulation includes:

[0138] Signal modulation module: performs random pulse position modulation and frequency agile modulation on the transmitting sub-pulse signal, and sets the basic parameters of the fuze transmitting signal s(t);

[0139] Signal transmitting and receiving module: The fuze transmitter radiates the transmitted signal s(t), and the fuze receiver receives the echo signal r(t);

[0140] Signal preprocessing module: The echo signal r(t) and the fuze's mixing signal are mixed and filtered sequentially to obtain the echo signal r′(t);

[0141] Random pulse position correlation module: After the echo signal r′(t) enters the correlator channel specified by the fuze, it performs random pulse position correlation operation with the fuze's local random pulse position reference signal sref0(t) to obtain the first-stage output signal u of the fuze correlator. R1 ;

[0142] Frequency agile related module: First stage output signal u of the fuze correlator R1 A frequency-agile correlation operation is performed with the local frequency-agile reference signal sref1(t) of the fuze to obtain the second-stage output signal u of the fuze correlator. R2 ;

[0143] Loop detection module: for the second-stage output signal u of the fuze correlator R2The system sequentially performs distance gating and constant false alarm rate (CFAR) detection. If a spike pulse near the preset detonation height is detected, the detection is successful. The distance of the distance gate is then adjusted to change the frequency of the local frequency-agile reference signal sref1(t) of the fuze. The system then returns to the signal transmission and reception module and continues to execute the signal transmission and reception module, signal preprocessing module, random pulse position correlation module, frequency agile correlation module, and cyclic detection module sequentially until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output. If no spike pulse near the preset detonation height is detected, the detection fails. The system then returns to the signal transmission and reception module and repeats the signal transmission and reception module, signal preprocessing module, random pulse position correlation module, frequency agile correlation module, and cyclic detection module sequentially until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output.

[0144] An anti-interference device based on a composite modulation fuze using random pulse position and frequency agile modulation includes:

[0145] Memory: Used to store computer programs implementing the above-described method for anti-interference using a composite modulation fuze based on random pulse position and agile frequency conversion;

[0146] Processor: Used to implement the above-described method for anti-interference using a composite modulation fuze based on random pulse position and agile frequency conversion when executing the computer program.

[0147] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned anti-interference method based on a random pulse position and frequency-agile composite modulation fuze.

[0148] The application effects of this invention will be described in detail below with reference to simulation experiments.

[0149] Figure 2 The figure shows the time-domain waveform of the transmitted signal s(t) radiated by the fuze transmitter after random pulse position and frequency agile composite modulation according to the present invention. As can be seen from the figure, the interval between each transmitted pulse of the fuze transmitted signal s(t) after random pulse position and frequency agile composite modulation according to the present invention is no longer equal, but has a certain degree of randomness, thereby enhancing the fuze's anti-interception capability.

[0150] Figure 3 The images show the spectrum of the transmitted signals from a traditional ultra-wideband fuze, a random pulse position fuze, a frequency agile fuze, and a composite modulation lead with random pulse position and frequency agile modulation, respectively. The analysis of... Figure 3 By comparing (ad) in the above, it can be seen that the spectrum of the traditional ultra-wideband fuze presents a comb-like spectrum with uniform spectral spacing, while the random pulse position and frequency agile modulation composite lead combines the advantages of random pulse position modulation and frequency agile modulation, forming a non-comb-like spectrum feature with both wide spectrum coverage and strong spectral randomness, which significantly improves the fuze's anti-interception capability.

[0151] Figure 4 The figures show the ambiguity function diagrams of the transmitted signals for traditional ultra-wideband fuzes, random pulse position fuzes, frequency agile fuzes, and composite modulation leads of random pulse position and frequency agile fuzes. These are obtained by analyzing... Figure 4 By comparing (ad) in the above, it can be seen that the ambiguity function of traditional ultra-wideband fuses and frequency agile fuses is "tack-shaped", with both distance and velocity ambiguity. The random pulse position fuse only has velocity ambiguity, while the ambiguity function of the random pulse position and frequency agile composite modulation fuse is "tack-shaped", with no obvious velocity and distance ambiguity, and has good anti-ambiguity capability.

[0152] Figure 5 and Figure 6 The curves show the correct detonation probability as a function of the input signal-to-interference ratio for traditional ultra-wideband fuses, random pulse position fuses, frequency agile fuses, and composite modulation leads of random pulse position and frequency agile frequency under sinusoidal aiming suppression interference and sinusoidal sweeping frequency interference, respectively. It can be seen that the correct detonation probability of the random pulse position and composite modulation fuse of frequency agile frequency is significantly greater than that of the single modulation fuse and the traditional ultra-wideband fuse. Through time-frequency two-dimensional collaborative de-periodicity operation, the resulting random pulse position and composite modulation fuse of frequency agile frequency has significantly stronger resistance to sinusoidal aiming suppression interference and sinusoidal sweeping frequency interference than the single modulation fuse and the traditional ultra-wideband fuse.

[0153] The above description is merely a specific embodiment of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the protection scope of the present invention.

Claims

1. A method for anti-interference based on a composite modulation fuze using random pulse position and frequency agile modulation, characterized in that: Includes the following steps: Step 1: Perform random pulse position modulation and frequency agile modulation on the transmitting sub-pulse signal, and set the basic parameters of the fuze transmitting signal s(t); Step 2: The fuze transmitter radiates the transmitted signal s(t), and the fuze receiver receives the echo signal r(t); Step 3: Mix and filter the echo signal r(t) and the fuze's mixing signal in sequence to obtain the echo signal r′(t); Step 4: After the echo signal r′(t) enters the designated correlator channel of the fuze, it undergoes random pulse position correlation operation with the fuze's local random pulse position reference signal sref0(t) to obtain the first-stage output signal u of the fuze correlator. R1 ; Step 5: The first stage output signal u of the fuse correlator R1 A frequency-agile correlation operation is performed with the local frequency-agile reference signal sref1(t) of the fuze to obtain the second-stage output signal u of the fuze correlator. R2 ; Step 6: Output signal u of the second stage of the fuze correlator R2 The process involves sequentially performing distance gate selection and constant false alarm detection. If a spike pulse is detected near the preset detonation height, the detection is successful. The distance gate is then adjusted to change the frequency of the local frequency-agile reference signal sref1(t) of the fuze. The process then returns to step 2 and continues with steps 2-6 until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output. If no spike pulse is detected near the preset detonation height, the detection fails. The process then returns to step 2 and repeats steps 2-6 until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output.

2. The anti-interference method based on a composite modulation fuze using random pulse position and frequency agile modulation as described in claim 1, characterized in that: Step 1 specifically includes: Step 1.1: The ultra-narrow pulse generator generates the transmitter sub-pulse signal: Among them, T p Where t is the pulse width and t is the time. Step 1.2: Set the random pulse position modulation parameters of the transmitted sub-pulse signal: modulation coefficient k is 0.3~0.5, code points m=6; set the frequency agile modulation parameters of the transmitted sub-pulse signal: Costas sequence C i = [1,3,4,2,6,5], step frequency interval Δf = 1GHz; Step 1.3: Set the basic parameters of the fuze transmission signal s(t): pulse width Tp = 1ns, pulse repetition frequency prf = 5MHz, number of periods N = 20, initial carrier frequency f0 = 22GHz, signal amplitude A = 1, correlation processing period Tr = 4us.

3. The anti-interference method for a composite modulation fuze based on random pulse position and frequency agile modulation according to claim 1, characterized in that: Step 2 specifically includes: Step 2.1: The fuze transmitter radiates the emitted signal s(t): Where j is the imaginary unit, f0 is the starting frequency of the transmitted signal, A is the amplitude of the transmitted signal, N is the number of periods, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. i To obey [0, kT] D A uniformly distributed random variable, f i The frequency corresponding to the i-th pulse; Step 2.2: The fuze receiver receives the echo signal r(t): Among them, A r Let f be the signal amplitude, τ = 2R(t) / c be the echo delay, R(t) be the distance between the fuze and the target, c be the speed of light, and f be the signal amplitude. d The Doppler frequency that occurs during the rendezvous between the projectile and the target. τ0 = 2R0 / c is the local time delay corresponding to the preset bomb height, R0 is the preset bomb height, and n(t) is the noise and interference signal.

4. The anti-interference method based on a composite modulation fuze using random pulse position and frequency agile modulation as described in claim 1, characterized in that: Step 3 specifically includes: Step 3.1: Generating a mixing signal with the fuze: Where N is the number of periods, j is the imaginary unit, and f j The frequency of the signal at the current moment; Step 3.2: Mix the echo signal r(t) with the mixing signal to obtain: Where Ar is the amplitude of the echo signal, N is the number of periods, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. i To obey [0, kT] D The uniformly distributed random variable, τ = 2R(t) / c is the echo delay, R(t) is the distance between the fuze and the target, c is the speed of light, and f is the distance between the fuze and the target. i f is the frequency corresponding to the i-th pulse. d The Doppler frequency that occurs during the rendezvous between the projectile and the target. τ0 = 2R0 / c is the local time delay corresponding to the preset bomb height, R0 is the preset bomb height, and n(t) is the noise and interference signal. f (t) represents the interference signal after mixing; Step 3.3: Filter equation (11) to obtain the echo signal r′(t): Where, Δf=f i -f j n f ′(t) represents the interference signal after mixing and filtering.

5. The anti-interference method based on a composite modulation fuze using random pulse position and frequency agile modulation as described in claim 1, characterized in that: Step 4 specifically includes: Step 4.1: When Δf = 0 for the echo signal r′(t) in equation (12), the echo signal r′(t) enters the correlator channel specified by the fuze, and at the same time, the fuze generates a local random pulse position reference signal sref0(t): Where A is the amplitude of the local random pulse position reference signal, N is the number of periods, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. j To obey [0, kT] D A uniformly distributed random variable, τ0=2R0(t) / c is the local time delay corresponding to the preset blast height, R0(t) is the preset blast height, and c is the speed of light; Step 4.2: The echo signal r′(t) and the local random pulse position reference signal sref0(t) are subjected to random pulse position correlation operation within one sampling pulse period Tr to obtain the first stage output signal u of the fuze correlator. R1 : Where AAr is the amplitude of the output signal, X i To obey [0, kT] D A uniformly distributed random variable, τ = 2R(t) / c is the echo delay, R(t) is the distance between the fuze and the target, f d The Doppler frequency that occurs during the rendezvous between the projectile and the target.

6. The anti-interference method based on a composite modulation fuze using random pulse position and frequency agile modulation as described in claim 1, characterized in that: Step 5 specifically includes: Step 5.1: Generate the local frequency agile reference signal sref1(t) using the fuze: Where N is the number of periods, j is the imaginary unit, and f j The frequency of the signal at the current moment; Step 5.2: First-stage output signal u of the fuze correlator R1 The local frequency-agile reference signal sref1(t) is subjected to frequency-agile correlation operation within one sampling pulse period Tr to obtain the second-stage output signal u of the fuze correlator. R2 : Where AAr is the amplitude of the output signal, w(t) is the transmitted sub-pulse signal, and T D X is the pulse repetition period. i With X j All obey [0, kT] D A uniformly distributed random variable, τ = 2R(t) / c is the echo delay, R(t) is the distance between the fuse and the target, c is the speed of light, τ0 = 2R0(t) / c is the local delay corresponding to the preset detonation height, R0(t) is the preset detonation height, f d f represents the Doppler frequency that may occur during the rendezvous between the projectile and the target. j The frequency of the local frequency-agile reference signal at the current moment.

7. An anti-interference system based on a composite modulation fuze using random pulse position and frequency agile modulation, characterized in that: include: Signal modulation module: performs random pulse position modulation and frequency agile modulation on the transmitting sub-pulse signal, and sets the basic parameters of the fuze transmitting signal s(t); Signal transmitting and receiving module: The fuze transmitter radiates the transmitted signal s(t), and the fuze receiver receives the echo signal r(t); Signal preprocessing module: The echo signal r(t) and the fuze's mixing signal are mixed and filtered sequentially to obtain the echo signal r′(t); Random pulse position correlation module: After the echo signal r′(t) enters the correlator channel specified by the fuze, it performs random pulse position correlation operation with the fuze's local random pulse position reference signal sref0(t) to obtain the first-stage output signal u of the fuze correlator. R1 ; Frequency agile related module: Fuze correlator first stage output signal u R1 A frequency-agile correlation operation is performed with the local frequency-agile reference signal sref1(t) of the fuze to obtain the second-stage output signal u of the fuze correlator. R2 ; Loop detection module: for the second-stage output signal u of the fuze correlator R2 The system sequentially performs distance gating and constant false alarm rate (CFAR) detection. If a spike pulse near the preset detonation height is detected, the detection is successful. The distance of the distance gate is then adjusted to change the frequency of the local frequency-agile reference signal sref1(t) of the fuze. The system then returns to the signal transmission and reception module and continues to execute the signal transmission and reception module, signal preprocessing module, random pulse position correlation module, frequency agile correlation module, and cyclic detection module sequentially until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output. If no spike pulse near the preset detonation height is detected, the detection fails. The system then returns to the signal transmission and reception module and repeats the signal transmission and reception module, signal preprocessing module, random pulse position correlation module, frequency agile correlation module, and cyclic detection module sequentially until 3-5 consecutive successful detections are achieved, at which point the detonation signal is output.

8. An anti-interference device based on a composite modulation fuze using random pulse position and frequency agile modulation, characterized in that: include: Memory: Used to store computer programs implementing the anti-interference method of a composite modulation fuze based on random pulse position and agile frequency conversion as described in any one of claims 1-6; Processor: Used to implement the anti-interference method of a composite modulation fuze based on random pulse position and agile frequency conversion as described in any one of claims 1-6 when executing the computer program.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the aforementioned anti-interference method based on a composite modulation fuze using random pulse position and agile frequency conversion.

Images