Interference and communication integrated waveform generation method based on time slot sampling

Abstract

The present invention proposes a method for generating an integrated waveform of interference and communication based on time slot sampling, and the implementation steps are as follows: initialize the parameters of time slot sampling; the jammer performs time slot sampling on the radar signal; the jammer constructs a matrix of basic signals; the jammer constructs a matrix of delayed signals; the jammer constructs a matrix of forwarding signals; the jammer obtains an integrated waveform of interference and communication. The present invention performs time slot sampling on the radar signal to obtain a time slot sampling signal, and generates a forwarding signal matrix after processing the time slot sampling signal. The first row signal of the forwarding signal matrix is ​​the τ time delay of the time slot sampling signal, and can generate multiple distance deception false targets after pulse compression processing at the radar end. The remaining L-1 rows of forwarding signals contain modulated communication information, which can obtain partial pulse compression gain at the radar signal processing end, produce a more powerful suppression interference effect, and thus improve power utilization.

Description

Technical Field

[0001] The present invention belongs to the field of radar interference and communication technology, relates to a waveform generation method, and further relates to an interference and communication integrated waveform generation method based on time slot sampling. Background Art

[0002] With the development of electronic information and communication technology, the communication working frequency band is gradually approaching the radar jammer working frequency band, so that there is a certain overlap between the two in the working frequency band. When the communication equipment and the radar jammer work at the same time, electromagnetic interference in the same frequency band will be generated, affecting the communication quality, and thus limiting the application scenarios of electronic equipment. Due to the compatibility of radar jammers and communication equipment in the hardware part, the overlap of frequency bands and the similarity of working principles, radar jammers and communication equipment are integrated into the same system to form an integrated radar jammer and communication system to realize the sharing of hardware resources and frequency bands, reduce equipment redundancy and improve spectrum utilization. In the application scenario, the radar jammer transmits a high-power integrated jammer communication signal, so that the main lobe of the beam is aimed at the interfered radar, and the side lobes realize communication, realizing interference and communication simultaneously in the space domain, time domain and frequency domain.

[0003] In order to achieve the integration of interference and communication, the key is to design a waveform that can meet the requirements of both interference and communication indicators. Currently, the most research is on the use of the same waveform for interference and communication. A waveform design method based on noise phase modulation interference modulates the communication information to be transmitted on the phase component of the noise interference signal to generate an integrated waveform. For example, in the paper "Covered Information Transmission Based on Noise Phase Modulation Interference Parasitic Spread Spectrum" published by Shi Rong, Hu Su, and Xu Jiantao, the communication information is modulated to the phase component of the noise phase modulation interference signal to generate an integrated waveform. However, the disadvantage is that the suppression interference generated by the waveform requires a large power to form effective interference, and the power utilization rate is low. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and to propose a method for generating an integrated interference and communication waveform based on time slot sampling, so as to solve the technical problem that the integrated waveform designed in the prior art has low power utilization when generating suppression interference.

[0005] To achieve the above object, the technical solution adopted by the present invention includes the following steps:

[0006] (1) Initialize the parameters of time slot sampling:

[0007] According to the duration T and bandwidth of the radar signal x(t), the repetition period of the initialization time slot sampling is T s , according to the characteristics of time slot sampling and forwarding interference and the communication rate R DThe index requires that the pulse width of the initialization time slot sampling is τ, where T s =(L+1)τ, L is a constant, 2≤L≤5, t represents the fast time;

[0008] (2) The jammer samples the radar signal in time slots:

[0009] The jammer samples the radar signal x(t) received at time t0 N times with equal time slots, and obtains N pulses with a width of τ and a repetition period of T. s The set S of time slot sampling signals:

[0010] S={x1(t),…,x n (t),…,x N (t)}

[0011]

[0012] Among them, x n (t) represents the nth time slot sampling signal, represents rounding down, t≥t0≥0, rect(·) represents the rectangular envelope function;

[0013] (3) The matrix of the jammer’s basic signal:

[0014] The jammer samples the signal x in each time slot n (t) Replicate L times and construct a basic signal matrix S with L rows and N columns of the time slot sampling signals contained in the time slot sampling signal set S L :

[0015]

[0016] Among them, x ln (t) is x n (t) corresponds to the lth basic signal;

[0017] (4) The jammer constructs a matrix of delayed signals:

[0018] The jammer is used for each basic signal x ln (t) Perform l times of τ time delay to obtain a matrix S of L delayed signals sorted by time Lτ :

[0019]

[0020] (5) The jammer constructs a matrix to forward the signal:

[0021] The jammer converts the binary data string it generates into q parallel data channels, performs MPSK modulation on the q parallel data channels, generates MPSK data, and modulates the MPSK data into S Lτ From the delayed signals except the first row, we get the forwarding signal matrix S of 1 row of unmodulated MPSK data and L-1 rows of modulated MPSK data. p , where q is a constant, q = log2(M), log2(·) represents a logarithmic function with base 2;

[0022] (6) Jammer obtains integrated jamming and communication waveform:

[0023] Jammer to S p The forwarding signal in the forwarding sequence is forwarded in time to obtain the designed interference and communication integrated waveform x j (t).

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The present invention performs time slot sampling on radar signals to obtain time slot sampling signals, and generates a forwarding signal matrix after processing the time slot sampling signals. The first row signal of the forwarding signal matrix is ​​the τ time delay of the time slot sampling signal, which can generate multiple distance deception false targets after pulse compression processing at the radar end, and the remaining L-1 rows of forwarding signals contain modulated communication information, which can obtain partial pulse compression gain at the radar signal processing end, generate a more powerful suppression interference effect, and thus improve power utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart for realizing the present invention;

[0027] Figure 2 A schematic diagram of the structure of the MPSK data generated by the present invention;

[0028] Figure 3 The forwarding signal matrix S of the present invention is p Time domain distribution diagram of

[0029] Figure 4 It is a bit error rate curve simulation diagram of the present invention;

[0030] Figure 5 It is a simulation diagram of the pulse compression result of the present invention;

[0031] Figure 6 It is a simulation diagram of the relationship curve between radar detection probability and interference-to-signal ratio when the present invention is an interference waveform;

[0032] Figure 7 This is a simulation diagram of the relationship between the radar detection probability and the interference-to-signal ratio when the existing noise phase modulation waveform is an interference waveform. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0034] See attached Figure 1 , the present invention comprises the following steps:

[0035] Step 1) Initialize the parameters of time slot sampling:

[0036] According to the duration T and bandwidth of the radar signal x(t), the repetition period of the initialization time slot sampling is T s , according to the characteristics of time slot sampling and forwarding interference and the communication rate R D The index requires that the pulse width of the initialization time slot sampling is τ, where T s =(L+1)τ, L is a constant, 2≤L≤5, and t represents fast time.

[0037] In this embodiment, the radar signal x(t) is a linear frequency modulation signal, and its expression is:

[0038]

[0039] Among them, A, T, k, They represent the amplitude, duration, frequency modulation slope, and initial phase of the radar signal x(t), respectively. t≥t0≥0, t0 is the starting time of the radar signal, exp(j·) represents a complex exponential function, and rect(·) represents a rectangular envelope function.

[0040] According to the principle of time slot sampling and forwarding interference, in order to generate multiple realistic false targets, the repetition period of time slot sampling T s The conditions that need to be met with respect to the duration and bandwidth of the radar signal are:

[0041]

[0042] Among them, the bandwidth of the radar signal B = k·T. According to the known radar bandwidth B and duration T in the above formula, the intermittent sampling period T is obtained. s In this embodiment, T = 100us, B = 10MHz, T s =4us.

[0043] According to the time slot sampling and forwarding interference principle and the communication rate R D The pulse width τ of the time slot sampling is related to T s The relationship between the communication rate and the

[0044]

[0045] Wherein, p is a constant, which indicates the total number of communication data that can be modulated within the time period τ, and L is a constant, 2≤L≤5. In this embodiment, R D =8M·Symbol·s -1 ,τ=1us.

[0046] Step 2) The jammer samples the radar signal in time slots:

[0047] The jammer samples the radar signal x(t) received at time t0 N times with equal time slots, and obtains N pulses with a width of τ and a repetition period of T. s The set S of time slot sampling signals:

[0048] S={x1(t),…,x n (t),…,x N (t)}

[0049]

[0050] Among them, x n (t) represents the nth time slot sampling signal, Indicates rounding down.

[0051] The result y of the signal in set S after pulse compression processing at the radar processing end s (t):

[0052]

[0053] Among them, sin(·) represents the sine function, cos(·) represents the cosine function, and f s =1 / T s , represents the frequency of time slot sampling, y(t) is the result of pulse compression processing of radar signal x(t), expressed as:

[0054]

[0055] Where sinc(·) represents the sinc function, which is represented by y s From the expression of (t), it can be seen that the signals in set S can form a signal with an amplitude of The main false target y(t) and the envelope obey The secondary false target group.

[0056] Step 3) The jammer builds a collection of basic signals:

[0057] The jammer samples the signal x in each time slot n (t) Replicate L times and construct a basic signal matrix S with L rows and N columns of the time slot sampling signals contained in the time slot sampling signal set SL :

[0058]

[0059] Among them, x ln (t) is x n (t) corresponds to the lth basic signal;

[0060] Step 4) The jammer constructs a matrix of delayed signals:

[0061] The jammer is used for each basic signal x ln (t) Perform l times of τ time delay to obtain a matrix S of L delayed signals sorted by time Lτ :

[0062]

[0063] Step 5) The jammer builds a matrix to forward the signal

[0064] The jammer converts the binary data string it generates into q parallel data channels, performs MPSK modulation on the q parallel data channels, generates MPSK data, and modulates the MPSK data into S Lτ From the delayed signals except the first row, we get the forwarding signal matrix S of 1 row of unmodulated MPSK data and L-1 rows of modulated MPSK data. p :

[0065]

[0066] Where q is a constant, q = log2(M), log2(·) represents the logarithmic function with base 2, and a(i,l,n) represents the logarithmic function of x. ln The i-th MPSK data modulated by the (t-lτ) signal, i∈{1,2…p}, p represents the total number of modulated MPSK data, and the structure of the modulated MPSK data is as follows: Figure 2 As shown, the sending time of each data in the figure is T r , modulate p MPSK data in the time width τ. The forwarding signal matrix S p The distribution in the time domain is Figure 3 As shown in the figure, there are L forwarding signals in the interval between two adjacent time slot sampling signals, of which the first forwarding signal is a copy of the time slot sampling signal and does not carry communication information, and the remaining L-1 forwarding signals are modulated with MPSK data. The forwarding signal modulated with MPSK data is discontinuous in phase from the time width τ due to the randomness of the communication signal. After pulse compression processing, it cannot form a pulse signal with a sin(·) envelope, but in an MPSK data modulation time T rIts phase is continuous. This part of the phase-continuous signal can obtain partial pulse compression gain. The output power at the radar end is much greater than the power of the noise signal as an interference signal. From the interference effect point of view, it forms a smart noise interference.

[0067] Step 6) The jammer obtains the integrated interference and communication waveform:

[0068] Jammer to S p The forwarding signal in the forwarding sequence is forwarded in time to obtain the designed interference and communication integrated waveform x j (t):

[0069]

[0070] The technical effects of the present invention are further described below in conjunction with simulation experiments:

[0071] 1. Simulation conditions and contents:

[0072] The radar signal used in the simulation is a linear frequency modulation signal, the noise channel is a Gaussian white noise channel, the MPSK in this embodiment is 8PSK, and the specific simulation parameters are shown in the following table:

[0073] Table 1 Simulation parameters

[0074] Parameter Type Numeric Parameter Type Numeric Pulse width / us 100 Radar bandwidth / MHz 10 Time slot sampling interval / us 4 Time slot sampling width / us 1 <![CDATA[Communication rate / M·Symbol·s -1 > 8 Distance between jammer and radar / km 20

[0075] Software environment: Inter(R)core(TM)i7-11700F CPU@2.50GHz, Matlab R2020b simulation software under Windows10 Home Chinese version 64-bit operating system.

[0076] Simulation 1: The bit error rate of the present invention is simulated, and the result is as follows: Figure 4 As shown;

[0077] Simulation 2: The pulse compression result of the present invention is simulated, and the result is as follows: Figure 5 As shown;

[0078] Simulation 3: The relationship curve between radar detection probability and interference signal ratio when the present invention is an interference waveform is simulated, and the result is as follows: Figure 6 As shown;

[0079] Simulation 4: The relationship curve between radar detection probability and interference-to-signal ratio is simulated when the existing noise phase modulation waveform is an interference waveform. The results are as follows: Figure 7 As shown;

[0080] 2. Analysis of simulation results:

[0081] Reference Figure 4The horizontal axis in the figure represents the bit signal-to-noise ratio, and the vertical axis represents the bit error rate of the integrated signal. It can be seen from the figure that when the bit signal-to-noise ratio is greater than 14dB, the bit error rate can be reduced to 10 -5 Theoretically, the communication rate can be guaranteed to be 8M·Symbol·s -1 Reliable transmission of communication information.

[0082] Reference Figure 5 , the horizontal axis in the figure represents the distance, and the vertical axis represents the normalized amplitude of the pulse compression of the integrated signal. As can be seen from the figure, the pulse compression output of the integrated signal produces a main false target and multiple symmetrically distributed secondary false targets, which has the effect of deception and interference. The pulse compression output of the forwarding signal modulated with the communication data becomes the noise floor, which plays a role in raising the radar detection threshold and has a suppressive interference effect.

[0083] Reference Figure 6 , the horizontal axis in the figure represents the interference-to-signal ratio, and the vertical axis represents the detection probability of the radar. It can be seen from the figure that as the interference-to-signal ratio increases, the detection probability of the radar gradually decreases. When the interference-to-signal ratio is 18dB, it can have a significant interference effect (the radar detection probability is less than 0.1).

[0084] Reference Figure 7 , the horizontal axis in the figure represents the interference-to-signal ratio, and the vertical axis represents the detection probability of the radar. It can be seen from the figure that as the interference-to-signal ratio increases, the detection probability of the radar gradually decreases. When the interference-to-signal ratio is 28dB, it can have a significant interference effect (the radar detection probability is less than 0.1).

[0085] contrast Figure 6 and Figure 7 It can be found that when there is a significant interference effect (radar detection probability is less than 0.1), the power of the integrated signal is 10 dB less than the power of the integrated signal generated by the prior art, and the power utilization rate is significantly higher than that of the prior art method.

[0086] In summary, the communication rate of the integrated waveform proposed in the present invention can reach M·Symbol·s -1 , and can generate deceptive and suppressive combined interference, which is superior to the existing integrated waveform in terms of power utilization.

Claims

1. A method for generating an integrated interference and communication waveform based on time slot sampling, characterized in that: The steps include: (1) Initialize the parameters of time slot sampling: According to the duration T and bandwidth of the radar signal x(t), the repetition period of the initialization time slot sampling is T s , according to the characteristics of time slot sampling and forwarding interference and the communication rate R D The index requires that the pulse width of the initialization time slot sampling is τ, where T s =(L+1)τ, L is a constant, 2≤L≤5, t represents the fast time; (2) The jammer samples the radar signal in time slots: The jammer samples the radar signal x(t) received at time t0 N times with equal time slots, and obtains N pulses with a width of τ and a repetition period of T. s The set S of time slot sampling signals: S={x1(t),…,x n (t),···,x N (t)} Among them, x n (t) represents the nth time slot sampling signal, represents rounding down, t≥t0≥0, rect(·) represents the rectangular envelope function; (3) The matrix of the jammer’s basic signal: The jammer samples the signal x in each time slot n (t) Replicate L times and construct a basic signal matrix S with L rows and N columns, containing the number of times of replication and the number of times of sampling signals contained in the time slot sampling signal set S. L : Among them, x ln (t) is x n (t) corresponds to the lth basic signal; (4) The jammer constructs a matrix of delayed signals: The jammer is used for each basic signal x ln (t) Perform l times of τ time delay to obtain a matrix S of L delayed signals sorted by time Lτ : (5) The jammer constructs a matrix to forward the signal: The jammer converts the binary data string it generates into q parallel data channels, performs MPSK modulation on the q parallel data channels, generates MPSK data, and modulates the MPSK data into S Lτ From the delayed signals except the first row, we get the forwarding signal matrix S of 1 row of unmodulated MPSK data and L-1 rows of modulated MPSK data. p , where q is a constant, q = log2(M), log2(·) represents a logarithmic function with base 2; (6) Jammer obtains integrated jamming and communication waveform: Jammer to S p The forwarding signal in the forwarding sequence is forwarded in time to obtain the designed interference and communication integrated waveform x j (t).

2. The interference and communication integrated waveform generation method based on time slot sampling according to claim 1 is characterized in that: The radar signal x(t) described in step (1) is expressed as: Among them, A, T, k, They represent the amplitude, duration, frequency modulation slope, and initial phase of the radar signal x(t), respectively, and exp(j·) represents a complex exponential function.

3. The interference and communication integrated waveform generation method based on time slot sampling according to claim 1 is characterized in that: The forwarding signal matrix S described in step (5) p , whose expression is: Among them, a(i,l,n) represents the ln The i-th MPSK data modulated by the (t-lτ) signal, i∈{1,2…p}, p represents the total number of modulated MPSK data.

4. The interference and communication integrated waveform generation method based on time slot sampling according to claim 3 is characterized in that: The interference and communication integrated waveform x described in step (6) j (t), its expression is:

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