Single-carrier phase-coherent pulse radar target velocity feature modulation method based on intermittent sampling and forwarding

Abstract

The application provides a single-carrier frequency phase modulation method for target speed of an intermittent sampling and forwarding single-carrier frequency phase pulse radar, which comprises the following steps: step 1, intercepting and estimating a radar transmitting signal; step 2, determining an intermittent sampling and forwarding jamming (ISRJ) control signal parameter according to a preset jamming effect; step 3, periodically sampling and forwarding the radar transmitting signal; and step 4, generating a speed false target. The application innovatively provides a single-carrier frequency phase pulse radar target speed deception jamming method based on intermittent sampling and forwarding, and expands the application of the intermittent sampling and forwarding technology in radar speed measurement jamming. Compared with frequency shift forwarding jamming and other forwarding type speed measurement jamming methods based on the DRFM technology, the single-carrier frequency phase pulse radar target speed deception jamming method based on intermittent sampling and forwarding has lower signal processing time delay and better realizability, because the method directly performs a forwarding operation after sampling. Compared with a traditional passive jamming, the method has a significant advantage in jamming energy.

Description

[Technical Field]

[0001] This invention discloses a target velocity feature modulation method for single-carrier coherent pulse radar based on intermittent sampling and forwarding, belonging to the field of active radar jamming technology. Specifically, it relates to the field of velocity measurement jamming of single-carrier coherent pulse radar. More specifically, it involves rapidly sampling and forwarding the detected radar signal, causing severe distortion in the radar velocity measurement processing results, thereby confusing and deceiving the single-carrier coherent pulse radar system. [Background Technology]

[0002] Coherent radar, employing techniques such as coherent accumulation, leverages the intra- or inter-pulse coherence of its waveform to achieve extremely high signal coherence processing gain, making it one of the most widely used radar systems today. Single-carrier coherent pulse radar, as one of the most representative narrowband coherent radars, is widely used in important areas such as ground moving target surveillance and short-range fire control systems. Developing jamming techniques for single-carrier coherent pulse radar has significant theoretical value and practical prospects for effectively reducing the exposure risk of high-value combat targets during maneuver.

[0003] The emergence of coherent radar has significantly suppressed the effectiveness of traditional jamming methods such as noise interference. To effectively jam coherent radar using jamming, the transmission power of the jammer would need to be greatly increased, which is clearly impractical, thus forcing the jammer to adopt coherent jamming techniques. The core of coherent jamming technology is to utilize the coherent characteristics of radar signals. By generating an interference signal highly correlated with the radar's transmitted signal, the interference signal also achieves high coherence processing gain, thereby suppressing or deceiving the coherent radar. Coherent jamming can be achieved through two methods: First, by performing high-precision parameter estimation on the intercepted radar signal, the jammer generates an interference signal with strong coherence based on the estimated parameters. This requires the jammer to know the radar system in advance and acquire the intra-pulse characteristics of the signal in real time, which is quite difficult. Second, by sampling the radar signal without distortion and then retransmitting it, also known as retransmitter jamming, which is widely used due to its simple principle and engineering implementation. With the emergence of advanced electronic devices such as high-speed broadband ADCs and DACs, and especially the gradual maturation of Digital Radio Frequency Memory (DRFM) technology, strong technical support has been provided for the engineering implementation of repeater-based interference. Currently, many studies have confirmed that DRFM technology can be used for deceptive interference of coherent pulse train signals, such as frequency shifting interference and pulse dropping interference.

[0004] Interrupted-Sampling Repeater Jamming (ISRJ) is a novel repeater jamming technique based on DRFM (Radio Frequency Modulation) technology. It was first proposed in 2006 by Wang Xuesong et al. from the National University of Defense Technology. ISRJ was developed to address two major challenges for repeater jammers when facing wide-bandwidth radar signals such as linear frequency modulated (LFM) signals: high-speed sampling and antenna isolation. Its core idea is to sample and repeat a short segment of radar signal with high fidelity, then immediately sample and repeat the next short segment of radar pulse signal. This rapid alternation of short sampling and repeating continues until the entire radar pulse signal ends. ISRJ has been developing for over a decade since its inception, and researchers have greatly enriched its jamming patterns by diversifying the modulation of the sampled signal before repeating or employing different repeating strategies.

[0005] In recent years, Xu Letao, Feng Dejun, and others from the National University of Defense Technology have systematically and deeply conducted research on intermittent sampling-forward jamming of broadband radar systems. Their research focused on the characteristics of the radar signal after sampling, one-dimensional ranging deception jamming methods for broadband radar based on ISRJ, and ISAR imaging deception jamming methods based on ISRJ, yielding fruitful results. Considering that the periodic "sampling-forward" process of ISRJ can inherently and regularly disrupt the phase coherence between radar transmitted pulses, significantly perturbing the spectral structure of the real target echo signal, and considering that the velocity measurement results of single-carrier coherent pulse radar are highly sensitive to the spectral structure of the radar echo, this characteristic can be applied to target velocity deception jamming of single-carrier coherent pulse radar, making it difficult for the radar to detect the movement of the real target and further improving the survivability of high-value operational maneuvering targets. [Summary of the Invention]

[0006] This invention aims to enrich the theoretical framework of ISRJ's operational mechanisms across more feature dimensions and fill the gap in research on the jamming effects of ISRJ in single-frequency coherent pulse radar. It proposes a single-carrier-frequency coherent pulse radar target velocity feature modulation method based on intermittent sampling and forwarding. The core idea lies in utilizing DRFM technology for high-speed periodic sampling and forwarding of the radar echo. After coherent accumulation processing, the echo signal results in multiple false targets with different spurious velocities in the radar velocity measurement. By adjusting the jammer parameters, the velocity, number, and energy intensity of the false targets can be controlled. To achieve the aforementioned velocity measurement deception jamming effect, this method employs the following steps:

[0007] Step 1: Interception and parameter estimation of radar transmitted signals

[0008] By utilizing the electronic reconnaissance devices integrated into the jamming system, radar transmission signals can be intercepted, the location of the enemy radar can be determined, and basic parameters of the signal waveform can be estimated, including: carrier frequency f. cSignal wavelength λ, pulse width T p Pulse repetition frequency f r .

[0009] Step 2: Determine the ISRJ control signal parameters based on the preset interference effect.

[0010] Intermittent sampling-forwarding interference (ISRJ) involves a single sampling and forwarding of the intercepted radar signal within a sampling-forwarding cycle (hereinafter referred to as the "sampling cycle"). This process can be equivalent to applying a pulsed ISRJ control signal to the original radar signal, with a pulse width of τ and a period of T. s (The corresponding frequency is its reciprocal f) s The pulsed control signal p(t) is used. Without considering velocity ambiguity, the velocity spectrum V of the deceptive false target generated by this invention can be obtained from... It is expressed as follows, where δ(·) is the impulse function, v represents the velocity value, v0 is the velocity value of the real target, and a n The energy intensity of the nth harmonic spectral line in the ISDJ control signal spectrum can be expressed by a. n =a n =τf s Sa(nτf s π)exp(-jnτf s π) represents, k i The energy intensity of the i-th spectral line in the comb spectrum of the original signal (given by the radar signal pulse width T) p and pulse repetition frequency f r (Decision). In summary, the speed value is... The energy intensity of the false target is a n k i The velocity value of the decoy target, the velocity, quantity, and energy intensity of the decoy target are determined by the ISRJ control signal parameters (pulse width τ, frequency f). s ) and radar transmitted signal parameters (pulse width T) p Wavelength λ, pulse repetition frequency f r The decision is made jointly. Based on different wartime strategic needs, the expected jamming effects are first set, such as equally spaced false target jamming, scattered false target jamming, suppression-type multi-false target jamming, and single main false target jamming. Then, combined with previously intercepted target radar waveform parameters, the parameters of the ISRJ control signal are further determined: ① Equally spaced false target jamming: based on the pulse repetition frequency f... r The magnitude determines the ISRJ control signal frequency f s This causes the false target to speed ① Equally spaced distribution; ② Scattered distribution of false targets for interference: based on the pulse repetition frequency f r The magnitude determines the ISRJ control signal frequency f s This causes the false target to speed Scattered distribution; ③ Suppression-type multi-false target jamming: based on pulse repetition frequency f r The magnitude determines the ISRJ control signal frequency f s This causes the false target to speed Get as close to each other as possible, and on this basis, control the pulse width τ of the ISRJ control signal to reduce a. n The resulting energy attenuation; ④ Single main decoy interference: control the pulse width τ of the ISRJ control signal, enhance a n The resulting energy decay makes the energy intensity of the false target a n k i When n > 1, it rapidly decays to an extremely low level, and based on this, it is determined according to the pulse repetition frequency f. r The magnitude determines the ISRJ control signal frequency f s Control the speed of the main false target to

[0011] Step 3: Periodic sampling and relaying of radar transmitted signals

[0012] Based on the ISRJ control signal parameters determined in step two: pulse width τ and frequency f s Configure the ISRJ jammer in one sampling period T s The sampling time width τ and sampling frequency f within the range s (Corresponding one-to-one with the above ISRJ control signal parameters, represented by the same symbols), the jammer configures the radar transmission signal according to the above parameters at a frequency of f. s The system performs periodic sampling. Within each sampling period, a slice of the sampled signal with a duration of τ is downgraded to the intermediate frequency (IF). Then, in the DRFM, it sequentially undergoes low-pass filtering, A / D conversion, storage, and D / A conversion before being immediately up-converted and forwarded at the ISRJ transmitter via a mixer. To ensure that the energy of the jamming signal generated by the jammer is significantly greater than the radar echo energy of the actual target, a high-power transmitting antenna is needed to radiate the signal in the direction of the incoming radar wave.

[0013] Step 4: Generation of velocity decoys

[0014] The interference signal j(t) generated by ISRJ enters the single-carrier coherent pulse radar system and is mixed with the local oscillator signal s in the mixer at the front end of the radar receiver. o (t)=exp(-j2πf c The intermediate frequency signal is obtained by multiplying t) and the baseband signal j after baseband filtering is affected by interference. base (t) After further coherent accumulation processing, the false target interference result preset in step two will be displayed, that is, the speed measurement deception interference effect of the method proposed in this invention is realized.

[0015] The beneficial effects of this invention are as follows:

[0016] First, an innovative single-carrier coherent pulse radar target velocity deception jamming method based on intermittent sampling and forwarding is proposed, which expands the application of intermittent sampling and forwarding technology in radar velocity measurement jamming.

[0017] Secondly, compared to other repeater-based velocity measurement jamming methods based on DRFM technology, the single-carrier frequency coherent pulse radar target velocity deception jamming method proposed in this invention, based on intermittent sampling and repeating, directly performs the repeating operation after sampling, resulting in lower signal processing latency and better feasibility. Furthermore, it has a significant advantage in terms of jamming energy compared to traditional passive jamming.

[0018] Third, by deeply integrating the spectral characteristics of the single-carrier frequency coherent pulse signal emitted by the radar, a mapping analytical model between jammer parameters and jamming effects was established. This allows users to generate flexible and diverse jamming effects, such as equally spaced false target jamming, scattered false target jamming, suppression-type multi-false target jamming, and single main false target jamming, simply by changing the duty cycle D and pulse width τ of the ISRJ pulse control signal. This enables flexible control over the speed, quantity, and energy intensity of false targets. [Attached Image Description]

[0019] Figure 1 Flowchart of a radar target velocity deception jamming method.

[0020] Figure 2 This is a schematic diagram of intermittent sampling and forwarding interference.

[0021] Figure 3(a) shows the time-domain waveform of the ISRJ control signal.

[0022] Figure 3(b) shows the spectrum of the ISRJ control signal.

[0023] Figure 4(a) is a comparison of the signal time domain before and after ISRJ interference.

[0024] Figure 4(b) is a comparison of the signal frequency domain before and after ISRJ interference.

[0025] Figure 5 This is a typical signal processing flow for a single-carrier frequency coherent pulse radar.

[0026] Figure 6 The radar velocity measurement results are without ISRJ interference.

[0027] Figure 7(a) shows the sampling frequency f s =0.12f r Furthermore, the speed and number of false targets when the duty cycle D = 0.4.

[0028] Figure 7(b) shows the sampling frequency f.s =0.125f r Furthermore, the speed and number of false targets when the duty cycle D = 0.4.

[0029] Figure 7(c) shows the sampling frequency f s =0.2f r Furthermore, the speed and number of false targets when the duty cycle D = 0.4.

[0030] Figure 7(d) shows the sampling frequency f. s =0.5f r Furthermore, the speed and number of false targets when the duty cycle D = 0.4.

[0031] Figure 8(a) shows the sampling frequency f s =1.125f r And the energy intensity of the dummy target when the duty cycle D = 0.4.

[0032] Figure 8(b) shows the sampling frequency f. s =3.125f r And the energy intensity of the dummy target when the duty cycle D = 0.4.

[0033] Figure 8(c) shows the sampling frequency f. s =5.125f r And the energy intensity of the dummy target when the duty cycle D = 0.4.

[0034] Figure 9(a) shows the sampling frequency f s =1f r The ISRJ interference failure status at that time.

[0035] Figure 9(b) shows the sampling frequency f. s =2f r The ISRJ interference failure status at that time.

[0036] Figure 9(c) shows the sampling frequency f. s =3f r The ISRJ interference failure status at that time.

[0037] Figure 10(a) shows the sampling frequency f. s =0.12f r And the energy intensity of the dummy target when the duty cycle D = 0.5.

[0038] Figure 10(b) shows the sampling frequency f. s =0.12f r And the energy intensity of the dummy target when the duty cycle D = 0.2.

[0039] Figure 10(c) shows the sampling frequency f. s =0.12f rAnd the energy intensity of the dummy target when the duty cycle D = 0.05.

Detailed Implementation Methods

[0040] To better understand the method of the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0041] This invention applies to fully coherent radars employing a single-carrier pulse system. Taking an X-band radar system as an example, the radar to be jammed transmits a signal with a center frequency of 10 GHz (in the following examples, it is assumed that the radar does not use frequency hopping technology), a signal wavelength λ of 3 cm, and a pulse repetition frequency f. r 100kHz, pulse width T p The radar uses a single-carrier coherent pulse train of 4 μs, accumulating 128 pulses per coherent pulse, with a velocity resolution of 11.7 m / s. It is assumed that the radial velocity of the real target relative to the radar is 230 m / s, and that the ISRJ jammer is mounted on the real target and moves along with it.

[0042] This invention relates to the following specific steps, the specific process of which is as follows: Figure 1 As shown.

[0043] Step 1: Interception and parameter estimation of radar transmitted signals

[0044] In practical applications, the electronic reconnaissance system needs to operate in real time and provide feedback on the waveform parameters of the radar transmitted signals. The ISRJ jammer then judges, processes, and reacts based on the intercepted information to continuously achieve the preset jamming effect. The basic parameters of the radar transmitted signals, such as the carrier frequency f, are obtained using the electronic reconnaissance system. c =10GHz, signal wavelength λ=3cm, pulse width T p =4μs, pulse repetition frequency f r =100kHz.

[0045] Step 2: Determine the ISRJ control signal parameters based on the preset interference effect.

[0046] Figure 2 The intermittent sampling signal shown can be equivalent to a pulse width of τ and a period of T. s The pulse-type ISRJ control signal p(t), T s The reciprocal of f is s , i.e., the ISRJ sampling frequency. The time domain p(t) and spectrum P(f) of the ISRJ control signal are shown in Figure 3(a) and Figure 3(b), respectively. p(t) and P(f) can be expressed by formulas (1) and (2):

[0047]

[0048]

[0049] Where t represents the time variable, when hour, otherwise g represents the g-th cycle of the ISRJ control signal in the time domain, j is the imaginary unit, and f represents the frequency variable. This indicates that the spectrum P(f) of the ISRJ control signal is a comb spectrum with the sinc function as its envelope. The parameters τ and f of the control signal... s These correspond to the single sampling duration and sampling period of the ISRJ jammer, respectively. By flexibly controlling these two important parameters of the jammer, a variety of preset jamming effects can be achieved. Conversely, based on the preset jamming effects, the jammer can deduce the parameters of the ISRJ jammer in reverse; this process will be completed in this step.

[0050] Step 3: Periodic sampling and relaying of radar transmitted signals

[0051] Based on the ISRJ control signal parameters determined in step two, the jammer performs continuous periodic sampling-forwarding processing on the single-carrier-frequency coherent pulse signal transmitted by the radar in real time. Unlike other pulse signals employing complex intra-pulse modulation techniques, the intra-pulse frequency of a coherent pulse train is a single-frequency signal with the carrier frequency. The coherent pulse signal of M pulses transmitted by the radar can be expressed as:

[0052]

[0053] In the formula, Let f be the constant initial phase of the radar transmitted signal. c Let u(t) be the radar carrier frequency, and u(t) be the envelope of the rectangular pulse train.

[0054]

[0055] In the formula, This represents the convolution operation. Calculations show that the spectrum of a coherent pulse train signal is a comb spectrum with the sinc function as its envelope, expressed as:

[0056]

[0057] From a time-domain perspective, the sampling-forwarding process of intermittent sampling-forwarding interference can be equivalent to applying a pulsed ISRJ control signal p(t) to the original radar signal. That is, the forwarded interference signal is the product of the real target echo s(t) and the ISRJ control signal p(t), as shown in Figure 4(a). The time-domain multiplication operation corresponds to the frequency-domain convolution operation, and the spectral structure of the interference signal is the convolution of the radar transmitted signal spectrum S(f) and the control signal spectrum P(f). Therefore, from a frequency-domain perspective, this process is equivalent to causing the original echo to produce a harmonic extension following a sinc attenuation distribution, as shown in Figure 4(b). Let the time-domain model of the interference signal forwarded by the ISRJ be j(t), and its spectrum be J(f), then the above process can be expressed by the following equation:

[0058] j(t)=s(t)·p(t) (6)

[0059]

[0060] Among them, a n =τf s Sa(nτf s π)exp(-jnτf s It must be pointed out that the jammer uses a high-power transmitting device, and the forwarding power of the jamming signal will be much stronger than the power of the real target echo s(t). Therefore, the influence of the real target echo on the radar velocity measurement results is ignored in the discussion of this invention.

[0061] Step 4: Generation of velocity decoys

[0062] according to Figure 5 The typical signal processing flow of a single-carrier coherent pulse radar is shown. The interference signal j(t) relayed by the ISRJ will be processed sequentially through a single sideband filter, a clutter suppression filter, a moving target indicator (MTI filter), a Doppler filter bank (MTD processing), and CFAR detection to obtain the final speed measurement interference result. Figure 6 The results are simulations of the actual target velocity under conditions without ISRJ interference, which are consistent with the set actual target velocity of 230 m / s.

[0063] Assuming the radar receiver uses zero-IF processing technology, due to the effect of the single-sideband filter, the spectrum range of interest to both the attacker and defender is limited to its passband, i.e., the effective velocity measurement interval B = [-f r / 2,+f r Within [ / 2], approximating each spectral line of the comb spectrum of a single-carrier coherent pulse signal as an impulse function, the amplitude spectrum of the coherent pulse train echo can be expressed as:

[0064]

[0065] Where i is the spectral line number of the comb spectrum of the original signal, and k i f represents the energy intensity of the i-th spectral line in the comb spectrum of the original signal. d If the Doppler frequency shift corresponds to the real target, then the interference baseband signal j base The spectrum of (t) is:

[0066]

[0067] Formula (9) illustrates the principle of velocity false target generation in ISRJ: When subjected to ISRJ, all spectral lines of the original signal change with a n For amplitude weighting, nf is extended in both the positive and negative directions of the frequency axis. s The spectral lines falling within range B are extracted by the single-sideband filter and the Doppler filter, indicating that ISRJ essentially utilizes the spectral energy of the original pulse signal itself to generate a false velocity target in the frequency domain. From the above analysis, it is easy to see that the sampling frequency f... s The weighting coefficient 'a' determines which spectral lines, after extension, fall within the passband of the single-sideband filter. n This also determines the degree of attenuation of these spectral lines after n continuations. Furthermore, due to a... n The expression shows that it is uniquely determined by the duty cycle of the control signal, D = τf. s The interference effect of ISRJ is mainly determined by the sampling frequency f. s The influence of two factors: the duty cycle D of the control signal and the sampling frequency. The sampling frequency is set to f. s =lf r Let F be the set of effective false target frequency points, then:

[0068]

[0069] Where Z represents the set of integers, and the velocity measurement results corresponding to the frequency points still satisfy the linear mapping relationship between Doppler frequency shift and velocity.

[0070] When the duty cycle of the ISRJ control signal is fixed at D = 0.4, the sampling frequency l is set to 0.12, 0.125, 0.2, and 0.5 respectively. The simulation results of speed measurement interference are shown in Figures 7(a)-(d). It can be concluded that, compared with the chaotic distribution of speed false targets in Figure 7(a), the speed false targets generated under the latter three sampling frequencies all satisfy the characteristic of equal interval distribution, and are distributed at the 8, 5, and 2 equal division points corresponding to B respectively.

[0071] When the duty cycle of the ISRJ control signal is fixed at D = 0.4, the sampling frequency l is set to 1.125, 3.125, and 5.125 respectively. The simulated speed measurement interference results are shown in Figures 8(a)-(c). Combined with Figure 7(b), it can be concluded that when the fractional part of the sampling frequency l remains unchanged, the velocity distribution position of the false target does not change, while the energy intensity of the false target decreases as the integer part of the sampling frequency l increases. In fact, the fundamental reason for this phenomenon lies in the spectral amplitude k of the coherent pulse train signal. i It follows a sinc-shaped envelope.

[0072] When the duty cycle of the ISRJ control signal is fixed at D = 0.4, and the sampling frequency l is set to 1, 2, and 3 respectively, the simulated speed measurement interference results are shown in Figures 9(a)-(c). Under these three sampling frequency settings, the radar speed measurement results are different from... Figure 6 The results shown are consistent with those without interference, indicating that the ISRJ interference is ineffective at this time. As can be seen from formula (10), when the value of l of the sampling frequency is exactly an integer, there is only one false target frequency point, which coincides with the real target. That is, the simulation results are consistent with the theory.

[0073] When the sampling frequency l is fixed at 0.12, and the duty cycle D of the ISRJ control signal is set to 0.5, 0.2, and 0.05 respectively, the simulated speed measurement interference results are shown in Figures 10(a)-(c). As the duty cycle D decreases, due to the amplitude weighting factor a... n As the main lobe width continues to increase, more and more spectral lines enter the passband of the single-sideband filter with relatively small attenuation, thus forming more and more effective velocity false targets. When the duty cycle decreases to 0.05, a large number of false target spectral lines almost completely cover the effective velocity measurement range, forming a suppression-like multi-false target interference effect.

[0074] The simulation results clearly show that the velocity, quantity, and energy intensity of the radar velocity decoys generated by the ISRJ jammer are affected by the jammer parameter f. s With D control, by presetting appropriate jammer parameters, diverse speed decoy target deception jamming effects can be achieved against single-carrier frequency coherent pulse radar, consistent with theoretical analysis, and also proving the effectiveness of the method proposed in this invention.

Claims

1. A target velocity feature modulation method for single-carrier coherent pulse radar based on intermittent sampling and forwarding, characterized in that, include: Step 1: Interception and parameter estimation of radar transmitted signals; By utilizing the electronic reconnaissance devices integrated into the jamming system, radar transmission signals can be intercepted, the location of the enemy radar can be determined, and the basic parameters of the signal waveform can be estimated. These basic parameters include the signal wavelength. λ Pulse repetition frequency f r Pulse width T p and carrier frequency f c ; Step 2: Determine the parameters of the intermittent sampling forwarding interference (ISRJ) control signal based on the preset interference effect; Intermittent sampling-forward jamming (ISRJ) within a single sampling-forward cycle (referred to as the sampling period) is equivalent to applying a pulsed ISRJ control signal to the original radar signal. Without considering velocity ambiguity, it generates the velocity spectrum of deceptive false targets. Depend on It means that, among them, Let be the impulse function. v Represents speed value, The velocity value of the actual target. The energy intensity of the nth harmonic spectral line in the ISDJ control signal spectrum is given by... express, k i The comb spectrum of the original signal i Energy intensity of root spectral lines; Step 3: Periodically sample and relay radar transmitted signals; Based on the ISRJ control signal parameters, configure the ISRJ jammer within one sampling period. T s Sampling pulse width within τ and sampling frequency f s The jammer modifies the radar's transmitted signals at a frequency of f s Periodic sampling, with a duration of [duration missing] within each sampling period. τ After the sampled signal slice is downgraded to the intermediate frequency, it undergoes low-pass filtering, A / D conversion, storage, and D / A conversion in the DRFM. Then, it is immediately up-converted and forwarded at the ISRJ transmitter via a mixer. Step 4: Generation of velocity decoys; Interference signal generated by ISRJ In a single-carrier coherent pulse radar system, the mixer at the front end of the radar receiver... Mid-range and local oscillator signals Multiplying yields the intermediate frequency signal, which is then filtered by the baseband to obtain the interfered baseband signal. After further coherent accumulation processing, the preset false target interference result will be displayed, that is, the speed measurement deception interference effect is achieved. In step three, the radar emits... M The coherent pulse signal of each pulse is represented as: (3) In the formula, The initial phase is a constant for the radar transmitted signal. For radar carrier frequency, u ( t () represents the envelope of a rectangular pulse train; (4) In the formula, This represents the convolution operation; calculations show that the spectrum of the coherent pulse train signal is a comb spectrum with the sinc function as its envelope, and its expression is: (5) in, Represents frequency variables; T p Indicates pulse width; In step four, the radar receiver employs zero-IF processing. Due to the single-sideband filter, the spectrum range of interest to both the attacker and defender is limited to its passband, i.e., the effective velocity measurement interval B = [- f r / 2,+ f r Within / 2]; each spectral line of the comb spectrum of a single-carrier coherent pulse signal is approximated as an impulse function, and the amplitude spectrum of the coherent pulse train echo is expressed as: (8) in, i These are the spectral line numbers for the comb spectrum of the original signal. k i The comb spectrum of the original signal i Energy intensity of root spectral lines f d The Doppler frequency shift corresponding to the real target is then affected by the interference baseband signal. The spectrum is: (9)。 2. The target velocity feature modulation method for single-carrier frequency phased pulse radar based on intermittent sampling and forwarding according to claim 1, characterized in that: In step two, the velocity value is The energy intensity of the false target is In other words, the velocity value of a decoy target, the velocity, quantity, and energy intensity of a decoy target are jointly determined by the ISRJ control signal parameters and the radar transmission signal parameters.

3. A target velocity feature modulation method for single-carrier frequency coherent pulse radar based on intermittent sampling and forwarding, as described in claim 1 or 2, characterized in that: In step two, based on the different needs of wartime strategies, the expected jamming effects are first set, including equally spaced false target jamming, scattered false target jamming, suppression-type multi-false target jamming, and single main false target jamming. Then, combined with the previously intercepted target radar waveform parameters, the parameters of the ISRJ control signal are further determined: ① Equally spaced false target interference: based on pulse repetition frequency f r The size determines the frequency of the ISRJ control signal. f s This causes the false target to speed Equally spaced distribution; ② Scattered false target interference: based on pulse repetition frequency f r The size determines the frequency of the ISRJ control signal. f s This causes the false target to speed Scattered distribution; ③ Suppression-type multi-false-target jamming: based on pulse repetition frequency f r The size determines the frequency of the ISRJ control signal. f s This causes the false target to speed Get them as close as possible to each other, and then control the pulse width of the ISRJ control signal. τ slow down The resulting energy attenuation; ④ Single main decoy interference: control the pulse width of the ISRJ control signal τ ,strengthen The resulting energy attenuation makes the energy intensity of the false target equal to exist The pulse rapidly decays to an extremely low level, and then, based on the pulse repetition frequency... f r The size determines the frequency of the ISRJ control signal. f s Control the speed of the main false target to .

4. The target velocity feature modulation method for single-carrier frequency coherent pulse radar based on intermittent sampling and forwarding according to claim 1, characterized in that: In step two, the time domain of the ISRJ control signal p ( t ) and spectrum P ( f The following are represented by formulas (1) and (2), respectively: (1) (2) in, t Represents a time variable, when hour, ,otherwise , g This indicates the first time domain of the ISRJ control signal. g One cycle, j The imaginary unit, f Represents frequency variables. This indicates the spectrum of the ISRJ control signal. P ( f () is a comb spectrum with the sinc function as its envelope; parameters of the control signal τ and f s These correspond to the single sampling duration and sampling period of the ISRJ jammer, respectively.

5. The target velocity feature modulation method for single-carrier frequency coherent pulse radar based on intermittent sampling and forwarding according to claim 1, characterized in that: The time-domain model of the interference signal relayed by the ISRJ is set as follows: j ( t ), the spectrum is J ( f ),but: (6) (7) in, .

6. The target velocity feature modulation method for single-carrier frequency phased pulse radar based on intermittent sampling and forwarding according to claim 1, characterized in that: Set the sampling frequency to Let F be the set of effective false target frequency points, then: (10) in, Representing a set of integers, the frequency points corresponding to the velocity measurement results still satisfy the linear mapping relationship between Doppler frequency shift and velocity. .

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