Radar deception jamming generation method based on time domain coding metasurface phase coding

Abstract

The application discloses a radar deception jamming generation method based on time domain coding metasurface phase coding, and comprises the following steps: setting the code length of an intra-pulse phase coding sequence, setting a plurality of coding modulation phase differences according to the time domain coding metasurface phase modulation capacity, and designing a time domain coding metasurface phase modulation function according to the set code length and the plurality of coding modulation phase differences; coding the plurality of coding modulation phase differences to obtain a coding set, initializing the intra-pulse phase coding sequence according to the coding set to obtain an initial intra-pulse phase coding sequence; setting a jamming position, and optimizing the initial intra-pulse phase coding sequence by using an optimization algorithm to obtain an optimal intra-pulse phase coding sequence; calculating an optimal coding modulation phase difference sequence according to the optimal intra-pulse phase coding sequence, and modulating a radar echo signal according to the time domain coding metasurface phase modulation function corresponding to the optimal coding modulation phase difference sequence to realize the deception jamming of the radar. The application can realize the deception jamming of the radar at any position.

Description

Technical Field

[0001] This invention belongs to the field of radar signal processing technology, specifically relating to a radar deception jamming generation method based on time-domain coded metasurface phase coding. Background Technology

[0002] Radar is an electronic device that detects targets by radiating electromagnetic waves. It is widely used in civilian fields such as aviation, traffic monitoring, and remote sensing imaging, as well as military fields such as search and early warning, tracking and guidance. With the emergence of new radar detection systems and technologies, the survivability of military targets on the battlefield is seriously threatened, and radar jamming technology urgently needs to be developed.

[0003] Current radar jamming methods can be categorized into active and passive jamming based on their jamming techniques. Active jamming utilizes digital radio frequency storage technology to collect radar waves and performs time-delay modulation for active retransmission, creating deceptive interference. However, while active jamming offers advantages such as high precision of jamming parameters and high jamming power, the received radar signal is a superposition of the original echo and the jamming signal; the target echo characteristics remain unchanged, making the jamming susceptible to being filtered out by signal processing. Time-domain coded metasurface modulation (TDMM) is a device capable of directly modulating electromagnetic waves with time-varying parameters and reflecting the echo. Using this device, zero-delay periodic phase-coded modulation of radar waves can be achieved for passive reflection, thereby concealing the target and creating deceptive interference.

[0004] However, existing radar deception jamming techniques that use periodic coding have problems such as simple coding rules and frequency harmonics, which leads to a certain regularity in the range dimension distribution of false targets after radar pulse compression, and can easily cause leakage of time-domain coded metasurface modulation parameters. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a radar deception jamming generation method based on time-domain encoded metasurface phase encoding. The technical problem to be solved by this invention is achieved through the following technical solution:

[0006] This invention provides a radar deception jamming generation method based on time-domain coded metasurface phase coding, comprising:

[0007] Establish radar and target models, and generate radar echo signals based on the radar and target models;

[0008] Set the code length of the intra-pulse phase coding sequence, set several coding modulation phase differences according to the phase modulation capability of the time-domain coding metasurface, and design the time-domain coding metasurface phase modulation function according to the set code length and several coding modulation phase differences.

[0009] A coding set is obtained by encoding several coded modulation phase differences, and an initial intra-pulse phase coding sequence is obtained by initializing the intra-pulse phase coding sequence according to the coding set.

[0010] An interference position is set, and an optimization algorithm is used to optimize the initial intra-pulse phase coding sequence to obtain the optimal intra-pulse phase coding sequence; wherein, the fitness function designed in the optimization algorithm is: the ratio of the interference peak value of the matched filter output at the set interference position to the sidelobe peak value of the matched filter output;

[0011] The optimal coded modulation phase difference sequence is calculated based on the optimal intra-pulse phase coding sequence. The radar echo signal is then phase-coded and modulated using the time-domain coded metasurface phase modulation function corresponding to the optimal coded modulation phase difference sequence to achieve radar deception and interference.

[0012] In one embodiment of the present invention, the designed time-domain coded metasurface phase modulation function is expressed as follows:

[0013]

[0014] Where r(t) represents the temporal coding metasurface phase modulation function, M represents the code length of the intra-pulse phase coding sequence, g(·) represents the gate function, and T c The symbol width is represented by exp(·), which represents an exponential function with the natural constant e as the base, and Φ represents the coded modulation phase difference sequence, where Φ = [φ1, φ2, ..., φ]. M ], where Φ(m) represents the coding-modulation phase difference of the m-th symbol.

[0015] In one embodiment of the present invention, initializing the intra-pulse phase coding sequence according to the coding set to obtain an initial intra-pulse phase coding sequence includes:

[0016] Each element of the intrapulse phase coding sequence is assigned a coding value randomly selected from the coding set to obtain the initial intrapulse phase coding sequence.

[0017] In one embodiment of the present invention, the fitness function formula is expressed as follows:

[0018]

[0019] Where f(·) represents the output of the matched filter, Δτ represents the time delay between the interference position and the target position, f Δτ (·) represents the peak interference value of the matched filter output at the interference location, f sidelobe (·) represents the sidelobe value of the matched filter output, max(·) represents the maximum value operation, T p Indicates the pulse width, x 3dB (·) represents the 3dB main lobe width in the time domain, sr Φ represents the radar echo signal, and Φ represents the coded modulation phase difference sequence corresponding to the intra-pulse phase coding sequence.

[0020] In one embodiment of the present invention, the optimization algorithm is a particle swarm optimization algorithm; correspondingly, the optimization algorithm is used to optimize the initial intra-pulse phase coding sequence to obtain the optimal intra-pulse phase coding sequence, including:

[0021] The optimal intra-pulse phase coding sequence is obtained by using the particle swarm optimization algorithm to optimize the initial intra-pulse phase coding sequence; wherein, each particle in the swarm is an intra-pulse phase coding sequence.

[0022] In one embodiment of the present invention, the optimal intra-pulse phase coding sequence is obtained by optimizing the initial intra-pulse phase coding sequence using a particle swarm optimization algorithm, including:

[0023] Initialize the population, and initialize the best historical position of particles in the population and the best historical position of the population, as well as the velocity and position of each particle;

[0024] The fitness value of each particle in the population is calculated based on the fitness function.

[0025] Update the best historical position of each particle and the best historical position of the population based on the fitness value of each particle.

[0026] The velocity and position of each particle are updated based on the updated best position in the particle history and the best position in the population history, in order to update the population.

[0027] Based on the updated population, repeat the above process until the maximum number of iterations is reached to obtain the optimal population, and use the optimal particle corresponding to the optimal population as the optimal intra-pulse phase encoding sequence.

[0028] In one embodiment of the present invention, updating the historical best position of a particle and the historical best position of the population based on the fitness value of each particle includes:

[0029] Sort all particles by their fitness values ​​from largest to smallest using the bubble sort algorithm;

[0030] Select the best fitness value for the particles and the best fitness value for the population based on the sorting results;

[0031] The particle's historical best position is updated based on its best fitness value, and the population's best position is updated based on the population's best fitness value.

[0032] In one embodiment of the present invention, updating the velocity and position of each particle based on the updated best position in particle history and the best position in population history includes:

[0033] The velocity of the corresponding particle is calculated based on the updated best position in the particle history and the best position in the population history, as well as the velocity and position of each initialized particle.

[0034] The position of the corresponding particle is updated based on the updated particle's velocity.

[0035] In one embodiment of the present invention, when the position of the updated particle exceeds the position boundary, the position of the updated particle is adjusted to the boundary value corresponding to the position boundary.

[0036] In one embodiment of the present invention, the phase-coded modulated radar echo signal is expressed as follows:

[0037] s opt (t)=s r (t)·r opt (t);

[0038] Among them, s opt (t) represents the phase-coded modulated radar echo signal, s r (t) represents the radar echo signal, r opt (t) represents the time-domain coded metasurface phase modulation function corresponding to the optimal coded modulation phase difference sequence.

[0039] The beneficial effects of this invention are:

[0040] This invention proposes a radar deception jamming generation method based on time-domain coded metasurface phase coding. From the perspective of radar signal processing, it can achieve radar deception jamming at any preset location. The method includes: establishing a radar and target model, and generating a radar echo signal based on the model; setting the code length of the intra-pulse phase coding sequence, setting several coded modulation phase differences based on the phase modulation capability of the time-domain coded metasurface, and designing a time-domain coded metasurface phase modulation function based on the set code length and the several coded modulation phase differences; encoding the several coded modulation phase differences to obtain a code set, and initializing the intra-pulse phase coding sequence based on the code set to obtain an initial intra-pulse phase coding sequence; setting the jamming location, and using an optimization algorithm to optimize the initial intra-pulse phase coding sequence to obtain an optimal intra-pulse phase coding sequence; wherein the fitness function designed in the optimization algorithm is the ratio of the peak interference value of the matched filter output at the jamming location to the peak sidelobe value of the matched filter output; calculating the optimal coded modulation phase difference sequence based on the optimal intra-pulse phase coding sequence, and performing phase coding modulation on the radar echo signal based on the time-domain coded metasurface phase modulation function corresponding to the optimal coded modulation phase difference sequence to achieve radar deception jamming. As can be seen, unlike existing periodic coding methods, this invention uses a designed time-domain coded metasurface phase modulation function to perform phase coding modulation on radar echo signals to achieve radar deception jamming. Furthermore, the phase coding sequence used in the phase coding modulation process is optimized by an optimization algorithm. The optimization algorithm transforms the complex numerical calculations required to form an ideal interference distribution into a coding optimization problem, avoiding complex numerical calculations and significantly reducing the difficulty of achieving deception jamming. Moreover, the optimized phase coding sequence no longer has regularity and there is no leakage problem of time-domain coded metasurface modulation parameters. It can achieve radar deception jamming at any preset position and conceal the main target.

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0042] Figure 1 This is a flowchart illustrating a radar deception jamming generation method based on time-domain coded metasurface phase coding provided in an embodiment of the present invention.

[0043] Figure 2 This is a flowchart illustrating the particle swarm optimization algorithm provided in an embodiment of the present invention;

[0044] Figure 3 This is an iterative schematic diagram of the average fitness function of the particle swarm optimization algorithm provided in the embodiments of the present invention;

[0045] Figure 4 This is a schematic diagram illustrating the optimized results of the -10dB signal-to-noise ratio intra-pulse phase coding sequence provided in an embodiment of the present invention;

[0046] Figure 5 This is a schematic diagram of the echo time-frequency of a linear frequency modulated signal without time-domain coding and metasurface phase modulation provided in an embodiment of the present invention;

[0047] Figure 6 This is a schematic diagram of the echo time-frequency of a linear frequency modulated signal that has undergone time-domain encoded metasurface phase modulation, provided in an embodiment of the present invention.

[0048] Figure 7 This is a schematic diagram of the -10dB signal-to-noise ratio pulse compression result provided in an embodiment of the present invention;

[0049] Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0050] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0051] Please see Figure 1 This invention provides a radar deception jamming generation method based on time-domain coded metasurface phase coding, comprising the following steps:

[0052] S10. Establish radar and target models, and generate radar echo signals based on the radar and target models.

[0053] This invention employs existing technology to establish a radar and target model. For example, assuming the radar transmission signal is a linear frequency modulated (LFM) signal, the radar and target model is established based on this LFM signal. The corresponding formula for the radar single-pulse transmission signal is expressed as follows:

[0054]

[0055] Among them, s t (t) represents the radar single-pulse transmitted signal, and rect(·) represents the rectangular function. T p K represents the radar pulse width. r f represents the modulation frequency of a linear frequency modulated signal. c denoted by , which represents the carrier frequency of the radar monopulse transmitted signal, and exp(·) represents an exponential function with the natural constant e as its base.

[0056] After pulse compression processing, the final output radar echo signal is expressed as follows:

[0057]

[0058] Among them, s r (t) represents the radar echo signal, and Δt represents the time delay from the radar transmitting the signal to the radar receiving the echo signal.

[0059] Furthermore, by performing matched filtering on the radar echo signal, the output of the unmodulated echo matched filter is expressed by the formula:

[0060]

[0061] Where h(t) represents the matched filter function, h(t) = s t * (-t).

[0062] S20. Set the code length of the intra-pulse phase coding sequence, set several coding modulation phase differences according to the phase modulation capability of the time-domain coding metasurface, and design the time-domain coding metasurface phase modulation function according to the set code length and several coding modulation phase differences.

[0063] The code length of the intra-pulse phase-coded sequence is set, denoted as M. Several coded modulation phase differences are set according to the phase modulation capability of the time-domain coded metasurface, denoted as [φ'1,φ'2,…,φ']. n ], where n represents the number of pre-set coded modulation phase differences, for example, n=4, and the sequence composed of several coded modulation phase differences is [0,90°,180°,270°].

[0064] Assuming the pulse width T p If the code length of the phase-coded sequence of the inner metasurface is M, then the time-domain coded metasurface phase modulation signal designed in this embodiment of the invention can be expressed by the following formula:

[0065]

[0066] Where r(t) represents the temporal coding metasurface phase modulation function, M represents the code length of the intra-pulse phase coding sequence, g(·) represents the gate function, and T c T represents the symbol width. c =T p / M, where Φ represents the coded modulation phase difference sequence, Φ(m) = [φ1, φ2, ..., φ M ], where Φ(m) represents the coding-modulation phase difference of the m-th symbol, and Φ(m) takes several coding-modulation phase differences [φ'1, φ'2, ..., φ']. n In the equation, a certain coded modulation phase difference is given by exp(·), which represents an exponential function with the natural constant e as the base.

[0067] S30. Encode several coded modulation phase differences to obtain a coding set, and initialize the intra-pulse phase coding sequence according to the coding set to obtain an initial intra-pulse phase coding sequence.

[0068] In this embodiment of the invention, several coded modulation phase differences are encoded to obtain a coded set, denoted as (1,...,n), where n is the number of coded modulation phase differences set in advance.

[0069] For example, if n = 4, the sequence of 4 coded modulation phase differences set according to the phase modulation capability of the time-domain coded metasurface is [0, 90°, 180°, 270°]. Then, [0, 90°, 180°, 270°] will be encoded to form a code set of [0, 1, 2, 3]. For another example, if n = 10, the sequence of 10 coded modulation phase differences set according to the phase modulation capability of the time-domain coded metasurface is [0, 30°, 60°, 90°, 120°, 150°, 180°, 240°, 270°]. Then, [0, 30°, 60°, 90°, 120°, 180°, 150°, 180°, 240°, 270°] will be encoded to form a code set of [0, 1, 2, 3, 4, 5, 6, 7, 8, 9].

[0070] Furthermore, this embodiment of the invention provides a method for generating an initial intrapulse phase coding sequence: randomly selecting each element of the intrapulse phase coding sequence from the coding set to obtain the initial intrapulse phase coding sequence.

[0071] For example: if code length M = 4, and the encoding set formed by S20 encoding is [0,1,2,3], then for an intra-pulse phase coding sequence of length 4, each element is randomly selected from the encoding set [0,1,2,3], for example, randomly selecting [3,0,1,2], i.e., the initial intra-pulse phase coding sequence is [3,0,1,2]. If code length M = 10, and the encoding set formed by S20 encoding is [0,1,2,3], then for an intra-pulse phase coding sequence of length 10, each element is randomly selected from the encoding set [0,1,2,3], for example, randomly selecting [3,0,1,2,2,1]. [3,0,1,2,2,1,0,3,2,0], that is, the initial intra-pulse phase coding sequence is [3,0,1,2,2,1,0,3,2,0]; code length M = 10. If the coding set formed by S20 coding is [0,1,2,3,4,5,6,7,8,9], then for an intra-pulse phase coding sequence of length 10, each element is randomly selected from the coding set [0,1,2,3,4,5,6,7,8,9], for example, randomly selecting [3,9,5,3,2,1,0,5,8,0], that is, the initial intra-pulse phase coding sequence is [3,9,5,3,2,1,0,5,8,0].

[0072] S40. Set the interference position and use the optimization algorithm to optimize the initial intra-pulse phase coding sequence to obtain the optimal intra-pulse phase coding sequence; wherein, the fitness function designed in the optimization algorithm is: the ratio of the interference peak value of the matched filter output at the interference position to the sidelobe peak value of the matched filter output.

[0073] In this embodiment of the invention, an interference position is pre-set. Assuming the time delay between the interference position and the target position is Δτ, the main lobe of the radar echo pulse compression after metasurface modulation is defined as being located at the pre-set interference position. The invention aims to suppress and shift the energy from the target position to the interference position through phase modulation and a radar matched filter mechanism. Based on the above concept, this embodiment of the invention designs a fitness function, the formula of which is:

[0074]

[0075] Where f(·) represents the output of the matched filter, Δτ represents the time delay between the interference position and the target position, f Δτ (·) represents the peak interference value of the matched filter output at the interference location, f sidelobe (·) represents the sidelobe value of the matched filter output, max(·) represents the maximum value operation, T p Indicates the pulse width, x 3dB (·) represents the 3dB main lobe width in the time domain, s r Let f(·) represent the radar echo signal, and Φ represent the coded modulation phase difference sequence corresponding to the intra-pulse phase coding sequence. In formula (5), f(·) and f(·) represent the coded modulation phase difference sequence. Δτ (·) and f sidelobe The calculation method for (·) can be achieved using existing technology, and will not be elaborated here.

[0076] Based on the fitness function in formula (5), this embodiment of the invention uses an optimization algorithm to find the optimal intra-pulse phase coding sequence from the initial intra-pulse phase coding sequence. The optimization algorithm is not limited here; for example, it can be a heuristic algorithm such as a genetic algorithm, or a convex optimization algorithm.

[0077] Next, taking the particle swarm optimization algorithm as an example, the optimization algorithm is the particle swarm optimization algorithm; the optimization algorithm is used to optimize the initial intra-pulse phase coding sequence to obtain the optimal intra-pulse phase coding sequence, including: using the particle swarm optimization algorithm to optimize the initial intra-pulse phase coding sequence to obtain the optimal intra-pulse phase coding sequence; wherein, each particle in the population is an intra-pulse phase coding sequence.

[0078] In one embodiment of the present invention, the optimal intra-pulse phase coding sequence is obtained by using a particle swarm optimization algorithm to optimize the initial intra-pulse phase coding sequence. See also... Figure 2 ,include:

[0079] S401. Initialize the population, and initialize the best historical position of particles in the population and the best historical position of the population, as well as the velocity and position of each particle.

[0080] Since the particle swarm optimization algorithm is used here, its population consists of several particles, each of which is an intra-pulse phase coding sequence. During the initialization phase, each particle is an initial intra-pulse phase coding sequence generated according to S30. The population size of the particle swarm optimization algorithm is set to `population_size`. Given the code length M of the intra-pulse phase coding sequence pre-set by S30, it can be seen that each particle in the population consists of a 1×M vector, and the population size is `population_size×M`.

[0081] For example, with code length M = 4, encoding set [0,1,2,3], and population_size = 3, three initial intra-pulse phase encoding sequences are randomly selected from the encoding set [0,1,2,3] to generate [3,0,1,2], [3,1,1,0], and [0,1,2,2]. These three initial intra-pulse phase encoding sequences form a population, and the population size is a 3×4 matrix.

[0082] At the same time, initialize the velocity and position of each particle in the population, denoted as v and x respectively, and initialize the best historical position of the particles and the best historical position of the population, denoted as pbest and Gbest respectively.

[0083] S402. Calculate the fitness value of each particle in the population based on the fitness function.

[0084] The fitness value of each particle is calculated according to the fitness function designed by formula (3). Specifically, the corresponding rect(·) is calculated according to the intra-pulse phase coding sequence of each particle in the current iteration. For the specific process, see the inverse process of S30. For example, code length M = 4, n = 4, the sequence of the four coding modulation phase differences is set as [0, 90°, 180°, 270°]. If the intra-pulse phase coding sequence in the current iteration is [3, 1, 0, 2], then the calculated coding modulation phase difference sequence Φ is [270°, 90°, 0, 180°].

[0085] Based on the coded modulation phase difference sequence, calculate f(·) and f(·) as shown in formula (3). Δτ (·) and f sidelobe (·), and then according to f(·), f Δτ (·) and f sidelobe (·) Calculate the fitness value for each particle.

[0086] S403. Update the best historical position of each particle and the best historical position of the population based on the fitness value of each particle.

[0087] This invention provides an optional scheme for updating the historical best position of a particle and the historical best position of the population based on the fitness value of each particle, including:

[0088] The fitness values ​​of all particles calculated by S402 (Φ) are sorted from largest to smallest using bubble sort. The order of particles in the population is then rearranged according to the fitness values, and the optimal fitness value f of each particle is selected based on the sorting results. pbest and the optimal fitness value f of the population gbest Based on the particle's optimal fitness value f pbest Update the best position in the particle history, pbest, and adjust it according to the population's best fitness value f. gbest Update the population's best location to Gbest.

[0089] S404. Update the velocity and position of each particle based on the updated best position in the particle history and the best position in the population history to update the population.

[0090] This embodiment provides an optional scheme to update the velocity and position of each particle based on the updated best historical position of the particle and the best historical position of the population, including:

[0091] Based on the updated best historical position pbest and the best historical position Gbest of the population, and the initialized velocity v and position x of each particle, the velocity v of the updated particle is calculated; the position x of the updated particle is calculated based on the velocity v of the updated particle. In one embodiment of the present invention, when the position of the updated particle exceeds the position boundary, the position of the updated particle is adjusted to the boundary value corresponding to the position boundary, that is, if the position boundary is [x... min ,x max When [the boundary position is exceeded], the position of particles exceeding the boundary position is adjusted to x. min or x max .

[0092] Based on the population updated in S404, repeat the above processes S402 to S404 until the maximum number of iterations, generation_size, is reached to obtain the optimal population. Then:

[0093] S405. The optimal particle corresponding to the optimal population is taken as the optimal intra-pulse phase coding sequence; that is, the optimal intra-pulse phase coding sequence is obtained through optimization.

[0094] S50. Calculate the optimal coding modulation phase difference sequence based on the optimal intra-pulse phase coding sequence, and perform phase coding modulation on the radar echo signal based on the time-domain coding metasurface phase modulation function corresponding to the optimal coding modulation phase difference sequence to achieve radar deception interference.

[0095] In this embodiment of the invention, the optimal intra-pulse phase coding sequence Φ is calculated based on the optimal intra-pulse phase coding sequence obtained through S40 optimization. optThe method is the same as the calculation method of the coded modulation phase difference sequence Φ in S40. Then, the formula for the time-domain coded metasurface phase modulation function corresponding to the optimal coded modulation phase difference sequence is expressed as:

[0096]

[0097] Where, r opt (t) represents the time-domain coded metasurface phase modulation function corresponding to the optimal coded modulation phase difference sequence, Φ opt This represents the optimal coded modulation phase difference sequence. Φ opt (m) represents the optimal coding modulation phase difference of the m-th symbol.

[0098] The formula for phase coding modulation of the radar echo signal based on the time-domain coded metasurface phase modulation function corresponding to the optimal coded modulation phase difference sequence is expressed as:

[0099] s opt (t)=s r (t)·r opt (t) (7)

[0100] Among them, s opt (t) represents the phase-coded modulated radar echo signal, s r (t) represents the radar echo signal, r opt (t) represents the time-domain coded metasurface phase modulation function corresponding to the optimal coded modulation phase difference sequence.

[0101] Furthermore, the modulated radar echo signal is subjected to matched filtering, and the output formula of the matched filter is expressed as:

[0102]

[0103] By adding metasurface modulation to the radar echo signal using formula (8), the phase characteristics of the radar echo can be changed, thereby achieving radar deception and interference.

[0104] To verify the effectiveness of the radar deception jamming generation method based on time-domain coded metasurface phase coding provided in this embodiment of the invention, the following experiments were conducted.

[0105] (1) Simulation conditions

[0106] The embodiments of this invention are pure software simulations, and the experimental platform is Matlab R2021a.

[0107] The radar and target model simulation uses a linear frequency modulated signal, and the parameters are shown in Table 1 below:

[0108] Table 1 Simulation Parameters

[0109]

[0110] A particle swarm optimization model was built using simulation software. The parameters used are shown in Table 2 below.

[0111] Table 2 Particle Swarm Optimization Algorithm Parameters

[0112]

[0113] Finally, the optimal intra-pulse phase coding sequence obtained by the particle swarm optimization algorithm is input into the radar detection model for matched filtering of the metasurface modulated echo to obtain the deception interference delay and the main-side lobe ratio, thus verifying the effectiveness of the method proposed in this invention.

[0114] (2) Simulation Results and Analysis

[0115] Please see Figure 3 , Figure 3 The iterative graph of the average fitness function of the particle swarm optimization algorithm is shown, indicating that the algorithm has stabilized after a maximum number of iterations. Please refer to [link / reference]. Figure 4 , Figure 4 This is the optimized result of the phase difference sequence. Based on this optimization result, the echo characteristics and pulse compression characteristics of the optimized coded modulation can be analyzed. Please refer to [link to relevant documentation]. Figure 5 and Figure 6 , Figure 5 and Figure 6 The images show the time-frequency plots of the unmodulated echo and the modulated echo after optimized coding, respectively. It can be seen that the unmodulated echo exhibits standard linear frequency modulation characteristics, while the frequency center of the modulated echo has shifted from zero, and the energy of the center frequency has been extended and spread throughout the entire repetition frequency range. This result verifies the effective modulation of the echo by optimized coding, which alters its echo characteristics. Please refer to [link to relevant documentation]. Figure 7 , Figure 7 The image shows a comparison of the matched filtering results between the unmodulated echo and the optimized coded modulated echo, as shown below. Figure 7 The modulated echo pulse compression peak is shifted to form a false target, and the interference sidelobes are suppressed, verifying the effectiveness of the algorithm.

[0116] The simulation experiments above demonstrate the reliability and effectiveness of the present invention, which can be used to optimize radar deception and jamming through metasurface phase coding.

[0117] In summary, the radar deception jamming generation method based on time-domain coded metasurface phase coding proposed in this invention can achieve radar deception jamming at any preset location. The method includes: establishing a radar and target model, and generating a radar echo signal based on the radar and target model; setting the code length of the intra-pulse phase coding sequence, setting several coded modulation phase differences based on the phase modulation capability of the time-domain coded metasurface, and designing a time-domain coded metasurface phase modulation function based on the set code length and several coded modulation phase differences; encoding the several coded modulation phase differences to obtain a code set, and initializing the intra-pulse phase coding sequence based on the code set to obtain an initial intra-pulse phase coding sequence; using an optimization algorithm to optimize the initial intra-pulse phase coding sequence to obtain an optimal intra-pulse phase coding sequence; wherein, the interference position is set, and the fitness function designed in the optimization algorithm is the ratio of the peak interference value of the matched filter output at the interference position to the peak sidelobe value of the matched filter output; calculating the optimal coded modulation phase difference sequence based on the optimal intra-pulse phase coding sequence, and performing phase coding modulation on the radar echo signal based on the time-domain coded metasurface phase modulation function corresponding to the optimal coded modulation phase difference sequence to achieve radar deception jamming. As can be seen, unlike existing periodic coding methods, the embodiments of the present invention use a designed time-domain coded metasurface phase modulation function to perform phase coding modulation on radar echo signals to achieve radar deception jamming. Moreover, the phase coding sequence used in the phase coding modulation process is optimized by an optimization algorithm. The optimization algorithm transforms the complex numerical calculations required to form an ideal interference distribution into a coding optimization problem, avoiding complex numerical calculations and significantly reducing the difficulty of achieving deception jamming. Furthermore, the optimized phase coding sequence no longer has regularity and there is no leakage problem of time-domain coded metasurface modulation parameters. It can achieve radar deception jamming at any preset position and conceal the main target.

[0118] Please see Figure 8 This invention provides an electronic device, including a processor 801, a communication interface 802, a memory 803, and a communication bus 804, wherein the processor 801, the communication interface 802, and the memory 803 communicate with each other through the communication bus 804.

[0119] Memory 803 is used to store computer programs;

[0120] When the processor 801 executes the program stored in the memory 803, it implements the steps of the radar deception jamming generation method based on time-domain coded metasurface phase coding described above.

[0121] This invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the radar deception jamming generation method based on time-domain coded metasurface phase coding described above.

[0122] For the electronic device / storage medium embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and relevant parts can be referred to in the description of the method embodiment.

[0123] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0124] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the specification and accompanying drawings, will understand and implement other variations of the disclosed embodiments in carrying out the claimed invention. In the specification, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. While certain measures are described in different embodiments, this does not mean that these measures cannot be combined to produce good results.

[0125] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A radar deception jamming generation method based on time-domain coded metasurface phase coding, characterized in that, include: Establish radar and target models, and generate radar echo signals based on the radar and target models; Set the code length of the intra-pulse phase coding sequence, set several coding modulation phase differences according to the phase modulation capability of the time-domain coding metasurface, and design the time-domain coding metasurface phase modulation function according to the set code length and several coding modulation phase differences. A coding set is obtained by encoding several coded modulation phase differences, and an initial intra-pulse phase coding sequence is obtained by initializing the intra-pulse phase coding sequence according to the coding set. An interference position is set, and an optimization algorithm is used to optimize the initial intra-pulse phase coding sequence to obtain the optimal intra-pulse phase coding sequence; wherein, the fitness function designed in the optimization algorithm is: the ratio of the interference peak value of the matched filter output at the set interference position to the sidelobe peak value of the matched filter output; The optimal coded modulation phase difference sequence is calculated based on the optimal intra-pulse phase coding sequence. The radar echo signal is then phase-coded and modulated using the time-domain coded metasurface phase modulation function corresponding to the optimal coded modulation phase difference sequence to achieve radar deception and interference.

2. The radar deception jamming generation method based on time-domain coded metasurface phase coding according to claim 1, characterized in that, The phase modulation function of the designed time-domain coded metasurface is expressed as follows: Where r(t) represents the time-domain coded metasurface phase modulation function, M represents the code length of the intra-pulse phase-coded sequence, g(!) represents the gate function, and T... c The symbol width is represented by exp(·), which represents an exponential function with the natural constant e as the base, and Φ represents the coded modulation phase difference sequence, where Φ = [φ1, φ2, ..., φ]. M ], where Φ(m) represents the coding-modulation phase difference of the m-th symbol.

3. The radar deception jamming generation method based on time-domain coded metasurface phase coding according to claim 1, characterized in that, The intrapulse phase coding sequence is initialized according to the coding set to obtain an initial intrapulse phase coding sequence, including: Each element of the intrapulse phase coding sequence is assigned a coding value randomly selected from the coding set to obtain the initial intrapulse phase coding sequence.

4. The radar deception jamming generation method based on time-domain coded metasurface phase coding according to claim 1, characterized in that, The fitness function formula is expressed as follows: Where f(·) represents the output of the matched filter, Δτ represents the time delay between the interference position and the target position, f Δτ (·) represents the peak interference output of the matched filter at the set interference location, f sidelobe (·) represents the sidelobe value of the matched filter output, max(·) represents the maximum value operation, T p Indicates the pulse width, x 3dB (·) represents the 3dB main lobe width in the time domain, s r Φ represents the radar echo signal, and Φ represents the coded modulation phase difference sequence corresponding to the intra-pulse phase coding sequence.

5. The radar deception jamming generation method based on time-domain coded metasurface phase coding according to claim 1, characterized in that, The optimization algorithm is a particle swarm optimization algorithm. The optimal intra-pulse phase coding sequence is obtained by optimizing the initial intra-pulse phase coding sequence using an optimization algorithm, including: The optimal intra-pulse phase coding sequence is obtained by using the particle swarm optimization algorithm to optimize the initial intra-pulse phase coding sequence; wherein, each particle in the swarm is an intra-pulse phase coding sequence.

6. The radar deception jamming generation method based on time-domain coded metasurface phase coding according to claim 5, characterized in that, The optimal intra-pulse phase coding sequence is obtained by optimizing the initial intra-pulse phase coding sequence using a particle swarm optimization algorithm, including: Initialize the population, and initialize the best historical position of particles in the population and the best historical position of the population, as well as the velocity and position of each particle; The fitness value of each particle in the population is calculated based on the fitness function. Update the best historical position of each particle and the best historical position of the population based on the fitness value of each particle. The velocity and position of each particle are updated based on the updated best position in the particle history and the best position in the population history, in order to update the population. Based on the updated population, repeat the above process until the maximum number of iterations is reached to obtain the optimal population, and use the optimal particle corresponding to the optimal population as the optimal intra-pulse phase encoding sequence.

7. The radar deception jamming generation method based on time-domain coded metasurface phase coding according to claim 6, characterized in that, Update the best historical position of each particle and the best historical position of the population based on the fitness value of each particle, including: Sort all particles by their fitness values ​​from largest to smallest using the bubble sort algorithm; Select the best fitness value for the particles and the best fitness value for the population based on the sorting results; The particle's historical best position is updated based on its best fitness value, and the population's best position is updated based on the population's best fitness value.

8. The radar deception jamming generation method based on time-domain coded metasurface phase coding according to claim 6, characterized in that, The velocity and position of each particle are then updated based on the updated best position in the particle's history and the best position in the population's history, including: The velocity of the corresponding particle is calculated based on the updated best position in the particle history and the best position in the population history, as well as the velocity and position of each initialized particle. The position of the corresponding particle is updated based on the updated particle's velocity.

9. The radar deception jamming generation method based on time-domain coded metasurface phase coding according to claim 8, characterized in that, When the position of the updated particle exceeds the position boundary, the position of the updated particle is adjusted to the boundary value corresponding to the position boundary.

10. The radar deception jamming generation method based on time-domain coded metasurface phase coding according to claim 2, characterized in that, The formula for the phase-coded modulated radar echo signal is as follows: s opt (t)=s r (t)·r opt (t); Among them, s opt (t) represents the phase-coded modulated radar echo signal, s r (t) represents the radar echo signal, r opt (t) represents the time-domain coded metasurface phase modulation function corresponding to the optimal coded modulation phase difference sequence.

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