Smart reflector design method, aerial vehicle, device, and storage medium

Abstract

Embodiments of the present application provide a smart reflecting surface design method, an aircraft, a device and a storage medium, and relate to the technical field of wireless communication. The method obtains a first response joint matrix of a smart reflecting surface and a second response joint matrix of a stealth material surface according to a first number of smart reflecting units on the smart reflecting surface, a second number of absorbing units on the stealth material surface, a third number of antennas on each radar, two-dimensional arrival angles and two-dimensional departure angles of signals between a target surface and radars; constructs a target optimization function according to an equivalent reflection vector of the stealth material surface, the first response joint matrix and the second response joint matrix, solves the target optimization function to obtain a regularization parameter, and obtains a reflection phase shift vector of the smart reflecting surface. A low-complexity algorithm is designed for the reflection phase shift vector of the smart reflecting surface, so that the smart reflecting surface can eliminate or offset the reflection signals of the target aircraft surface at all radar echoes and cross links, and an almost complete electromagnetic stealth effect is achieved.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to intelligent reflector design methods, aircraft, devices, and storage media. Background Technology

[0002] With the development of wireless communication technology and radar detection equipment, electromagnetic stealth technology applied to aircraft can improve their survivability and defense capabilities, playing an increasingly important role in military combat. Electromagnetic stealth technology uses specific methods to minimize the strong scattering sources of radar signals from an aircraft, thereby significantly reducing the electromagnetic wave energy that can be intercepted by radar receivers, making the aircraft almost invisible to radar systems.

[0003] In related technologies, reconfigurable / controllable metasurface-assisted intelligent adaptive electromagnetic stealth systems are studied from the perspective of signal processing. These systems utilize intelligent reflective surfaces to reconfigure wireless channels, and the intelligent reflective surfaces can adjust the reflected phase and amplitude of incident signals in real time, transforming the wireless propagation environment from passive adaptation to active control. However, the design of intelligent reflective surfaces in these technologies cannot achieve satisfactory stealth effects. Summary of the Invention

[0004] The main objective of this application is to propose a smart reflective surface design method, aircraft, device, and storage medium to improve the stealth effect of target aircraft equipped with smart reflective surfaces in electromagnetic systems.

[0005] To achieve the above objectives, a first aspect of this application proposes a smart reflective surface design method applied to a target aircraft in an electromagnetic stealth system. The electromagnetic stealth system includes the target aircraft, and the surface of the target aircraft includes a smart reflective surface and a stealth material surface. The smart reflective surface and the stealth material surface are located on the same target surface. The method includes:

[0006] The first response joint matrix of the smart reflective surface and the second response joint matrix of the stealth material surface are obtained based on the first number of smart reflective units on the smart reflective surface, the second number of radar-absorbing units on the stealth material surface, the third number of antennas on the radar, and the two-dimensional angle of arrival and two-dimensional angle of departure of the signal between the target surface and the radar.

[0007] A target optimization function is constructed based on the equivalent reflection vector of the stealth material surface, the first joint response matrix, and the second joint response matrix, and the regularization parameters are obtained by solving the target optimization function.

[0008] The reflection phase shift vector of the intelligent reflective surface is calculated based on the regularization parameter, the equivalent reflection vector, the first response joint matrix, and the second response joint matrix.

[0009] In some embodiments, obtaining the first joint response matrix of the smart reflector and the second joint response matrix of the stealth material surface based on the first number of smart reflector units on the smart reflector surface, the second number of radar-absorbing units on the stealth material surface, the third number of antennas on the radar, and the two-dimensional angle of arrival and two-dimensional angle of departure of the signal between the target surface and the radar includes:

[0010] The radar array response vector, the reflector array response vector of the smart reflector, and the material array response vector of the stealth material are obtained based on the first number of smart reflector units on the smart reflector surface, the second number of absorber units on the stealth material surface, the third number of antennas on the radar, and the two-dimensional angle of arrival and two-dimensional angle of departure of the signal between the target surface and the radar.

[0011] The first cascaded array response vector of the smart reflective surface and the second cascaded array response vector of the stealth material surface are obtained based on the response vector of the reflective surface array and the response vector of the material array.

[0012] The first joint response matrix and the second joint response matrix are obtained based on the first cascaded array response vector, the second cascaded array response vector, and the radar array response vector.

[0013] In some embodiments, obtaining the radar array response vector of the radar, the reflector array response vector of the smart reflector, and the material array response vector of the stealth material surface based on a first number of smart reflector units on the smart reflector surface, a second number of radar-absorbing units on the stealth material surface, a third number of antennas on the radar, and the two-dimensional angle of arrival and two-dimensional angle of departure of the signal between the target surface and the radar includes:

[0014] The radar array response vector is obtained based on the third quantity and the two-dimensional departure angle;

[0015] The response vector of the reflective surface array is obtained based on the first quantity and the two-dimensional angle of arrival;

[0016] The material array response vector is obtained based on the second quantity and the two-dimensional angle of arrival.

[0017] In some embodiments, obtaining the first cascaded array response vector of the smart reflective surface and the second cascaded array response vector of the stealth material surface based on the reflective surface array response vector and the material array response vector includes:

[0018] Obtain the response vector of the first reflector array corresponding to the current radar, and the response vectors of the second reflector arrays corresponding to other radars;

[0019] The first cascaded array response vector is obtained based on the first reflective surface array response vector and the second reflective surface array response vector;

[0020] Obtain the first material array response vector corresponding to the current radar, and the second material array response vectors corresponding to other radars;

[0021] The second cascaded array response vector is obtained based on the first material array response vector and the second material array response vector.

[0022] In some embodiments, obtaining the first joint response matrix and the second joint response matrix based on the first cascaded array response vector, the second cascaded array response vector, and the radar array response vector includes:

[0023] The receiving beamforming gain of the radar is obtained based on the radar's receiving beamforming vector, the path gain of the radar reaching the target surface, and the radar array response vector.

[0024] The transmit beamforming gain of the radar is obtained based on the transmit beamforming vector of the radar, the path gain, and the radar array response vector.

[0025] The cross-link beam gain between any two radars is obtained based on the received beamforming gain and the transmitted beamforming gain.

[0026] The first joint response matrix is ​​obtained based on the first cascaded array response vector and the cross-link beam gain;

[0027] The second joint response matrix is ​​obtained based on the second cascaded array response vector and the cross-link beam gain.

[0028] In some embodiments, constructing the objective optimization function based on the equivalent reflection vector of the stealth material surface, the first joint response matrix, and the second joint response matrix includes:

[0029] A first objective function is constructed based on the regularization parameter, the equivalent reflection vector, the first joint response matrix, and the second joint response matrix;

[0030] A reflection vector function is constructed based on the regularization parameter, the equivalent reflection vector, the first response joint matrix, and the second response joint matrix.

[0031] The target optimization function is obtained based on the first objective function and the reflection vector function.

[0032] In some embodiments, solving the objective optimization function to obtain the regularization parameters includes:

[0033] Minimizing the first objective function yields the first constraint function;

[0034] A second constraint function is obtained by making the reflection vector function less than or equal to the maximum reflection amplitude of the intelligent reflection unit;

[0035] A one-dimensional search algorithm is used to find the regularization parameter in the positive real number field that satisfies the first constraint function and the second constraint function.

[0036] To achieve the above objectives, a second aspect of this application provides an aircraft in an electromagnetic stealth system, comprising:

[0037] The aircraft surface includes a smart reflective surface and a stealth material surface, the smart reflective surface and the stealth material surface being located on the same target surface; the reflection phase shift vector of the smart reflective surface is obtained according to the smart reflective surface design method as described in any of the first aspects.

[0038] To achieve the above objectives, a third aspect of the present application provides an electronic device, the electronic device including a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method described in the first aspect.

[0039] To achieve the above objectives, a fourth aspect of the present application provides a storage medium that stores a computer program, which, when executed by a processor, implements the method described in the first aspect.

[0040] The intelligent reflector design method, aircraft, device, and storage medium proposed in this application obtain a first joint response matrix of the intelligent reflector and a second joint response matrix of the stealth material surface based on a first number of intelligent reflective units on the intelligent reflector, a second number of radar-absorbing units on the stealth material surface, a third number of antennas on the radar, and the two-dimensional angle of arrival and two-dimensional angle of departure of the signal between the target surface and the radar. Then, a target optimization function is constructed based on the equivalent reflection vector of the stealth material surface, the first joint response matrix, and the second joint response matrix, and the regularization parameter is obtained by solving the target optimization function. Finally, the reflection phase shift vector of the intelligent reflector is calculated based on the regularization parameter, the equivalent reflection vector, the first joint response matrix, and the second joint response matrix. Compared to relying on a single method to achieve the stealth effect of the target aircraft, this application combines the intelligent reflector and the plane composed of stealth material, and designs a low-complexity algorithm for the reflection phase shift vector of the intelligent reflector. This allows the intelligent reflector in the electromagnetic stealth system to eliminate or cancel the reflection signals of the target aircraft surface from all radar echoes and cross-links, achieving a near-complete electromagnetic stealth effect. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the electromagnetic stealth system in an embodiment of this application.

[0042] Figure 2 This is an optional flowchart of the intelligent reflective surface design method provided in the embodiments of this application.

[0043] Figure 3 This is an embodiment of the present application. Figure 1 The flowchart for step S110.

[0044] Figure 4 This is an embodiment of the present application. Figure 3 The flowchart for step S111.

[0045] Figure 5 This is an embodiment of the present application. Figure 3 The flowchart of step S113.

[0046] Figure 6 Examples of embodiments in this application Figure 2 The flowchart for step S120.

[0047] Figure 7 This is a graph showing the relationship between the total power of the radar received signal and the shortest distance to the target surface in the intelligent reflective surface design method and related technologies provided in this application.

[0048] Figure 8 This is a graph showing the relationship between the total power of the radar received signal and the number of radars in the intelligent reflector design method and related technologies provided in the embodiments of this application.

[0049] Figure 9 This is a schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0051] It should be noted that although functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0053] With the development of wireless communication technology and radar detection equipment, electromagnetic stealth technology applied to aircraft can improve their survivability and defense capabilities, playing an increasingly important role in military combat. Electromagnetic stealth technology uses specific methods to minimize the strong scattering sources of radar signals from an aircraft, thereby significantly reducing the electromagnetic wave energy that can be intercepted by radar receivers, making the aircraft almost invisible to radar systems.

[0054] In related technologies, novel radar-absorbing / reflecting materials, due to their high electromagnetic wave absorption efficiency, are used in the field of electromagnetic stealth. However, these materials can only reduce the radar cross-section of a target to a certain extent and cannot achieve near-complete stealth. Furthermore, some types of electromagnetic stealth materials can only achieve the expected stealth performance under specific incident electromagnetic wave angles and frequencies. The high maneuverability of aircraft leads to rapid changes in detection frequency and incident wave angle, making electromagnetic stealth materials unable to adapt to rapidly changing environments. Another approach studies intelligent adaptive electromagnetic stealth systems assisted by reconfigurable / controllable metasurfaces from a signal processing perspective. This involves designing intelligent reflective surfaces to reconfigure wireless channels. The intelligent reflective surfaces adjust the reflected phase and amplitude of the incident signal in real time, transforming the wireless propagation environment from passive adaptation to active control. Unlike relying on stealth materials, intelligent reflective surfaces offer more flexible and real-time control over incident electromagnetic waves, and their operating frequency and angle / direction range are wider. This adaptability allows them to assist or supplement imperfect electromagnetic stealth technologies in highly dynamic wireless environments. However, the design of intelligent reflective surfaces in related technologies cannot achieve satisfactory stealth results.

[0055] Based on this, embodiments of this application provide a smart reflective surface design method, aircraft, device, and storage medium, which combines a smart reflective surface with a plane composed of stealth materials. At the same time, a low-complexity algorithm is designed for the reflection phase shift vector of the smart reflective surface, so that the smart reflective surface in the electromagnetic stealth system can eliminate or cancel the reflection signals of the target aircraft surface in all radar echoes and cross links, achieving a near-complete electromagnetic stealth effect.

[0056] This application provides a smart reflective surface design method, aircraft, device, and storage medium, which are specifically described through the following embodiments. First, the electromagnetic stealth system in the embodiments of this application is described.

[0057] Reference Figure 1 , Figure 1 This is a schematic diagram of the electromagnetic stealth system in an embodiment of this application.

[0058] Figure 1 The electromagnetic stealth system comprises a target aircraft, designed to achieve stealth against at least one radar. The target aircraft's surface (referred to as the target surface) has L receiving and sensing devices, one smart reflector, and one stealth material surface. The stealth material surface is an equivalent surface on the target surface coated with electromagnetic absorbing material. Specifically, the smart reflector and the stealth material surface are located on the same target surface. The smart reflector has a first number of N1 smart reflective elements, and the stealth material surface has a second number of N2 absorbing elements. Each radar has a third number of M antennas. It can be understood that the target aircraft's surface can be divided into multiple target surfaces.

[0059] Assuming that the intelligent reflective elements in the intelligent reflective surface, the radar-absorbing elements in the stealth material surface, and the antennas in each radar are all arranged in a uniform planar array, and if a two-dimensional Cartesian coordinate system (xy) is established on the target surface, then the intelligent reflective elements distributed along the x-axis are represented as N. 1,x The intelligent reflective units distributed along the y-axis are represented as N. 1,y The absorbing elements distributed along the x-axis are represented as N. 2,x The absorbing elements distributed along the y-axis are represented as N. 2,y Antennas distributed along the x-axis are represented as M. x Antennas distributed along the y-axis are denoted as M. y And N1 = N 1,x ×N 1,y N2 = N 2,x ×N 2,y M = M x ×M y N in the diagram 2,y With N 1,y Similarly, the first and second quantities in the diagram are for illustrative purposes only and are not intended to be limited.

[0060] Assuming the number of radars is K, then the radars are denoted as Radar 1, Radar 2, ..., Radar k, ... Radar K. Since... Figure 1 In the electromagnetic stealth system, the intelligent reflective surface and the stealth material surface together constitute the target surface. Therefore, for the k-th radar, the intelligent reflective surface and the stealth material surface share the two-dimensional angle of arrival and the two-dimensional angle of departure between the target surface and radar k obtained by L receiving and sensing devices at the target surface.

[0061] The two-dimensional angle of arrival is expressed as:

[0062]

[0063] The two-dimensional departure angle is represented as:

[0064]

[0065] Where k = 1, ..., K, Represents the azimuth angle in a two-dimensional angle of arrival. Represents the horizontal angle in a two-dimensional angle of arrival. Represents the azimuth angle in a two-dimensional departure angle. This represents the horizontal angle in a two-dimensional departure angle.

[0066] In one embodiment, the reflection vector of the smart reflector is θ, and the path gain from radar k to the target surface is... The transmit power of each radar is P, and the beamforming vector transmitted by radar k is w. k The received beamforming vector obtained by the receiving sensing device on the target surface is Superscript (·) T This represents the transpose operation of a matrix or vector. The path gain can be obtained from the radar equations.

[0067] Furthermore, embodiments of this application utilize absorption efficiency to evaluate the impact of stealth materials on overall performance, wherein the absorption efficiency is expressed as... This is used to quantify the effectiveness of stealth materials against radar electromagnetic waves. Based on the absorption efficiency, the equivalent reflection vector of the stealth material surface is obtained, expressed as:

[0068]

[0069] in, This represents the equivalent reflection phase shift of the stealth material surface. The equivalent reflection phase shift It is not adjustable and is determined solely by the physical properties of its electromagnetic absorbing material. This parameter can be obtained through prior information obtained by modeling or actual measurement.

[0070] therefore, Figure 1 The cascaded reflection vector of the target surface of the medium-range target aircraft is

[0071] In a specific implementation scenario, assume that the target surface of the target aircraft in the electromagnetic stealth system consists of L=9 receiving and sensing devices and 1 device with N1=N 1,x It consists of a smart reflective surface with 2 smart reflective units and a stealth material surface with N² = 100 × 2 = 200 absorber units. The absorption efficiency of the stealth material surface is... Its equivalent reflection phase shift follows a uniformly distributed random generation in the interval [0, 2π). The element spacing of the intelligent reflection unit on the intelligent reflection surface and the wave-absorbing unit on the stealth material surface is Δ. e =λ / 4, where λ is the signal wavelength.

[0072] Furthermore, assuming K = 3 radars are deployed, and this multi-radar system operates at an ultra-high frequency of 150 GHz, therefore the signal wavelength λ = 0.05 m. Also, assuming each radar is equipped with M = 8 × 8 = 64 transmitting / receiving antennas, and the spacing between antennas is Δ... a =λ / 2 = 0.025m. Therefore, the path gain referenced at 1m along each independent link in the target vehicle and multi-radar system is α = -30dB, the transmit power of each radar is set to P = 15dBm, and the shortest distance between the target surface and the radar is 100m. In this embodiment, it is assumed that the target surface and all radars are deployed on the same two-dimensional plane, then... Therefore, in this embodiment, when designing the intelligent reflective surface, only the two-dimensional departure angle needs to be considered. Real-time changes.

[0073] The following describes the intelligent reflective surface design method in the embodiments of this application.

[0074] Figure 2 This is an optional flowchart of the intelligent reflective surface design method provided in the embodiments of this application. Figure 2 The method may include, but is not limited to, steps S110 to S130. It is also understood that this embodiment... Figure 2 The order of steps S110 to S130 is not specifically limited, and the order of steps can be adjusted or some steps can be reduced or added according to actual needs.

[0075] Step S110: Based on the first number of intelligent reflective units on the intelligent reflective surface, the second number of absorbing units on the stealth material surface, the third number of antennas on the radar, and the two-dimensional angle of arrival and two-dimensional angle of departure of the signal between the target surface and the radar, obtain the first joint response matrix of the intelligent reflective surface and the second joint response matrix of the stealth material surface.

[0076] In one embodiment, reference is made to Figure 3 , Figure 3 This is an embodiment of the present application. Figure 1 The flowchart for step S110 specifically includes the following steps S111 to S113:

[0077] Step S111: Based on the first number of intelligent reflective units on the intelligent reflective surface, the second number of absorbing units on the stealth material surface, the third number of antennas on the radar, the radar array response vector of the radar with two-dimensional angle of arrival and two-dimensional departure angle of the signal between the target surface and the radar, the reflective surface array response vector of the intelligent reflective surface, and the material array response vector of the stealth material surface.

[0078] In one embodiment, reference is made to Figure 4 , Figure 4This is an embodiment of the present application. Figure 3 The flowchart of step S111 specifically includes the following steps S1111 to S1113:

[0079] Step S1111: Obtain the radar array response vector based on the third quantity and the two-dimensional departure angle.

[0080] Wherein, the radar array response vector of the k-th radar Represented as:

[0081]

[0082] The above λ represents the signal wavelength, Δ e The cell spacing represents the target surface. Indicates the Kronecker product. This represents the guiding vector function.

[0083] Step S1112: Obtain the reflector array response vector based on the first quantity and the two-dimensional angle of arrival.

[0084] Wherein, the intelligent reflector's reflector array response vector at the k-th radar is... Represented as:

[0085]

[0086] Step S1113: Obtain the material array response vector based on the second quantity and the two-dimensional angle of arrival.

[0087] Wherein, the material array response vector of the stealth material surface at the k-th radar is... Represented as:

[0088]

[0089] Step S112: Obtain the first cascaded array response vector of the smart reflective surface and the second cascaded array response vector of the stealth material surface based on the response vector of the reflective surface array and the response vector of the material array.

[0090] In one embodiment, the first reflector array response vector corresponding to the current radar and the second reflector array response vectors corresponding to other radars are obtained, and the first cascaded array response vector is obtained based on the first reflector array response vector and the second reflector array response vector.

[0091] For example, for the k-th radar, it is taken as the current radar, and its corresponding reflector array response vector is obtained as the first reflector array response vector. Therefore, the first reflector array response vector is expressed as:

[0092]

[0093] Next, other radars are acquired, such as the j-th radar, and its corresponding reflector array response vector is obtained as the second reflector array response vector. Therefore, the second reflector array response vector is expressed as:

[0094]

[0095] Therefore, the response vector of the first cascaded array is expressed as:

[0096]

[0097] in,(·) H The symbol represents the Hamiltonian transpose of a matrix, and ⊙ represents the Hadamard product.

[0098] Similarly, the first material array response vector corresponding to the current radar and the second material array response vectors corresponding to other radars are obtained, and the second cascaded array response vector is obtained based on the first material array response vector and the second material array response vector.

[0099] For example, for the k-th radar, it is taken as the current radar, and its corresponding material array response vector is obtained as the first material array response vector. Therefore, the first material array response vector is expressed as:

[0100]

[0101] Next, other radars are acquired, such as the j-th radar, and its corresponding material array response vector is obtained as the second material array response vector. Therefore, the second material array response vector is expressed as:

[0102]

[0103] Therefore, the response vector of the second cascaded array is expressed as:

[0104]

[0105] in,(·) H The symbol represents the Hamiltonian transpose of a matrix, and ⊙ represents the Hadamard product.

[0106] Step S113: Obtain the first response joint matrix and the second response joint matrix based on the first cascaded array response vector, the second cascaded array response vector, and the radar array response vector.

[0107] In one embodiment, reference is made to Figure 5 , Figure 5 This is an embodiment of the present application. Figure 3 The flowchart for step S113 specifically includes the following steps S1131 to S1135:

[0108] Step S1131: Obtain the radar's receiving beamforming gain based on the radar's receiving beamforming vector, the path gain of the radar reaching the target surface, and the radar array response vector.

[0109] The receiving beamforming gain is expressed as:

[0110]

[0111] Step S1132: Obtain the radar's transmit beamforming gain based on the radar's transmit beamforming vector, path gain, and radar array response vector.

[0112] The transmit beamforming gain is expressed as:

[0113]

[0114] Step S1133: Obtain the cross-link beam gain between any two radars based on the received beamforming gain and the transmitted beamforming gain.

[0115] The combined receive and transmit beam gain of the cross-link between radar j and radar k is denoted as the cross-link beam gain, and is expressed as:

[0116]

[0117] Step S1134: Obtain the first joint response matrix based on the first cascaded array response vector and the cross-link beam gain.

[0118] The joint matrix of the first response is represented as:

[0119]

[0120] As can be seen, in the above calculations, j=1 and k=1 were selected sequentially for calculation. And so on, until the result is calculated. Thus, the first response joint matrix D is obtained.

[0121] Step S1135: Obtain the second response joint matrix based on the second cascaded array response vector and the cross-link beam gain.

[0122] The second response joint matrix is ​​represented as follows:

[0123]

[0124] As can be seen, in the above calculations, j=1 and k=1 were selected sequentially for calculation. And so on, until the result is calculated. Thus, the second response joint matrix E is obtained.

[0125] After obtaining the first response joint matrix D and the second response joint matrix E through the above process, the objective function is optimized based on these matrices.

[0126] Step S120: Construct the objective optimization function based on the equivalent reflection vector of the stealth material surface, the joint matrix of the first response, and the joint matrix of the second response, and solve the objective optimization function to obtain the regularization parameters.

[0127] In one embodiment, reference is made to Figure 6 , Figure 6 Examples of embodiments in this application Figure 2 The flowchart for step S120 specifically includes the following steps S121 to S126:

[0128] Step S121: Construct the first objective function based on the regularization parameters, the equivalent reflection vector, the joint matrix of the first response, and the joint matrix of the second response.

[0129] In one embodiment, the reflection coefficient of the intelligent reflector satisfies the constant modulus constraint during the design process by using a regularization parameter δ. The first objective function is expressed as:

[0130]

[0131] in, Let represent the N1×N1 identity matrix, φ represent the equivalent reflection vector, D represent the first response joint matrix, E represent the second response joint matrix, δ represent the regularization parameter, and ‖·‖ represent the L2 norm of the complex vector. -1 This indicates the matrix inversion operation.

[0132] Step S122: Construct the reflection vector function based on the regularization parameter, the equivalent reflection vector, the joint matrix of the first response, and the joint matrix of the second response.

[0133]

[0134] Among them, i n Represents the identity matrix The column vector of the nth column.

[0135] Step S123: Obtain the target optimization function based on the first objective function and the reflection vector function.

[0136] The objective function is expressed as:

[0137]

[0138]

[0139] Step S124: Minimize the first objective function to obtain the first constraint function.

[0140] To satisfy the minimum mean square error condition, the first constraint function is expressed as:

[0141]

[0142] Step S125: Obtain the second constraint function by making the reflection vector function less than or equal to the maximum reflection amplitude of the intelligent reflection unit.

[0143] Due to the passive reflection property of the intelligent reflector, its reflection vector θ must satisfy the constant modulus constraint, expressed as:

[0144]

[0145] The second constraint function, derived from the constant modulus constraint, is expressed as:

[0146]

[0147] Where, β max ≤1 represents the maximum reflection amplitude of the passive intelligent reflective unit in the intelligent reflective surface, and |·| represents the modulus of the complex number.

[0148] Step S126: Use a one-dimensional search algorithm to find regular parameters in the positive real number domain that satisfy the first constraint function and the second constraint function.

[0149] After obtaining the first and second constraint functions, a one-dimensional search algorithm is used to find regularization parameters in the positive real number domain that satisfy both the second and first constraint functions. In other words, the first constraint function needs to be minimized by changing the value of the regularization parameter δ under the constraint of the second constraint function. For example, the one-dimensional search algorithm searches for parameters in one-dimensional space, looking for parameters that satisfy both constraints in the positive real number domain. First, the search range is determined, i.e., the range of values ​​for the regularization parameter. This can be set according to the actual situation, choosing a suitable initial search interval. Next, the search step size or step value is determined, i.e., the change in the regularization parameter in each iteration. Similarly, the step size can be a small positive number chosen according to actual needs. Then, starting from the beginning of the initial search interval, the value of the regularization parameter is gradually changed using the step size, and the values ​​of the first objective function and the reflection vector function are calculated. Based on the values, a judgment is made: if the corresponding constraint condition is satisfied, the search stops; otherwise, iteration continues until the condition is satisfied or a certain number of iterations are reached. Finally, the regularization parameter or approximate solution that satisfies both constraints is taken as the output result.

[0150] Step S130: Calculate the reflection phase shift vector of the intelligent reflective surface based on the regularization parameter, the equivalent reflection vector, the joint matrix of the first response, and the joint matrix of the second response.

[0151] The above steps yield the regularization parameters, equivalent reflection vector, joint matrix of the first response, and joint matrix of the second response. Therefore, the optimization problem is solved using the minimum mean square error criterion, and the final reflection phase shift vector is expressed as follows:

[0152]

[0153] This application presents an electromagnetic stealth method based on a smart reflector design using the minimum mean square error criterion. By rationally designing the reflection phase shift vector of the smart reflector, it achieves electromagnetic stealth by eliminating multi-station radar signal detection. This method can eliminate or cancel signals reflected from all radar echoes and cross-links on the target surface, exhibiting low complexity and meeting real-time signal processing requirements. A low-complexity algorithm achieves complete electromagnetic stealth for target aircraft in multi-radar scenarios. Furthermore, it maintains a very low received signal power level even under imperfect conditions.

[0154] In some specific embodiments, the proposed intelligent reflector design method of this application is compared with the total power of multi-radar received signals under other intelligent reflector reflection phase shift designs in related technologies under different scenarios on the MATLAB platform to illustrate that the embodiment of this application is more effective. Other intelligent reflector reflection phase shift designs include: 1) random phase shift design: the reflection phase shift vector of the intelligent reflector is randomly generated by a uniform distribution in the interval [0, 2π); 2) codebook search based on discrete Fourier transform: the reflection phase shift vector of the intelligent reflector is searched in a codebook based on discrete Fourier transform to minimize the sum of radar received signal power.

[0155] Figure 7 This is a graph showing the relationship between the total power of the radar received signal and the shortest distance to the target surface in the intelligent reflector design method and related technologies provided in this application. Figure 7 The following conclusions can be drawn: Compared with random phase-shift design and codebook search based on discrete Fourier transform, the total power of the multi-radar received signals obtained by the intelligent reflector proposed in this application embodiment in the electromagnetic stealth system is significantly lower than that of random phase-shift design and codebook search based on discrete Fourier transform. This verifies the effectiveness of the intelligent reflector design method proposed in this application embodiment in reducing or even eliminating the total power of multi-radar reflected signals when achieving electromagnetic stealth.

[0156] Figure 8 This is a graph showing the relationship between the total power of the radar received signal and the number of radars in the intelligent reflector design method and related technologies provided in this application. Figure 8The following conclusions can be drawn: the total power of the received signals from multiple radars increases with the increase of the number of radars; however, compared with two reference systems—one without a smart reflector and the other using a random phase-shift design—the smart reflector design method proposed in this application significantly slows down the rate at which the total power of the received radar signals increases with the number of radars K when achieving electromagnetic stealth. This verifies the effectiveness of the smart reflector design method proposed in this application in simultaneously eliminating or reducing reflected signals to multiple radars in multiple directions when achieving electromagnetic stealth.

[0157] The technical solution provided in this application provides a first response joint matrix for the intelligent reflective surface and a second response joint matrix for the stealth material surface based on the first number of intelligent reflective units on the intelligent reflective surface, the second number of radar-absorbing units on the stealth material surface, the third number of antennas on the radar, and the two-dimensional angle of arrival and two-dimensional angle of departure of the signal between the target surface and the radar. Then, a target optimization function is constructed based on the equivalent reflection vector of the stealth material surface, the first response joint matrix, and the second response joint matrix, and the regularization parameter is obtained by solving the target optimization function. Finally, the reflection phase shift vector of the intelligent reflective surface is calculated based on the regularization parameter, the equivalent reflection vector, the first response joint matrix, and the second response joint matrix. Compared to relying on a single method to achieve the stealth effect of a target aircraft, this application combines the intelligent reflective surface and the plane composed of stealth material, and designs a low-complexity algorithm for the reflection phase shift vector of the intelligent reflective surface. This allows the intelligent reflective surface in the electromagnetic stealth system to eliminate or cancel the reflection signals from all radar echoes and cross-links on the target aircraft surface, achieving a near-complete electromagnetic stealth effect.

[0158] This application also provides an aircraft in an electromagnetic stealth system, the aircraft including an aircraft surface, the aircraft surface including a smart reflective surface and a stealth material surface, the smart reflective surface and the stealth material surface being located on the same target surface; the reflection phase shift vector of the smart reflective surface is obtained according to the smart reflective surface design method as described in any of the above claims.

[0159] This application also provides an electronic device, including:

[0160] At least one memory;

[0161] At least one processor;

[0162] At least one program;

[0163] The program is stored in memory, and the processor executes at least one program to implement the intelligent reflective surface design method described above. The electronic device can be any intelligent terminal, including mobile phones, tablets, personal digital assistants (PDAs), and in-vehicle computers.

[0164] Please see Figure 9 , Figure 9 The hardware structure of an electronic device according to another embodiment is illustrated. The electronic device includes:

[0165] The processor 901 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application.

[0166] The memory 902 can be implemented in the form of ROM (Read-Only Memory), static storage device, dynamic storage device, or RAM (Random Access Memory). The memory 902 can store the operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 902 and called and executed by the processor 901 using the intelligent reflective surface design method of the embodiments of this application.

[0167] The 903 input / output interface is used to implement information input and output.

[0168] Communication interface 904 is used to enable communication and interaction between this device and other devices. Communication can be achieved via wired means (e.g., USB, Ethernet cable) or wireless means (e.g., mobile network, Wi-Fi, Bluetooth).

[0169] Bus 905 transmits information between various components of the device (e.g., processor 901, memory 902, input / output interface 903, and communication interface 904);

[0170] The processor 901, memory 902, input / output interface 903, and communication interface 904 are connected to each other within the device via bus 905.

[0171] This application embodiment also provides a storage medium that stores a computer program, which, when executed by a processor, implements the above-described intelligent reflective surface design method.

[0172] Memory, as a non-transitory storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0173] The intelligent reflector design method, intelligent reflector design device, electronic device, and storage medium proposed in this application combine an intelligent reflector and a stealth material plane to achieve near-complete electromagnetic stealth. This is achieved by calculating the first joint response matrix of the intelligent reflector and the second joint response matrix of the stealth material plane based on the first number of intelligent reflector units on the intelligent reflector, the second number of radar-absorbing units on the stealth material plane, the third number of antennas on the radar, and the two-dimensional angle of arrival and two-dimensional angle of departure of the signal between the target surface and the radar. A target optimization function is then constructed based on the equivalent reflection vector of the stealth material plane, the first joint response matrix, and the second joint response matrix, and regularization parameters are obtained by solving the target optimization function. Finally, the reflection phase shift vector of the intelligent reflector is calculated based on the regularization parameters, the equivalent reflection vector, the first joint response matrix, and the second joint response matrix. Compared to relying on a single method to achieve stealth for a target aircraft, this application combines an intelligent reflector and a stealth material plane, and designs a low-complexity algorithm for the reflection phase shift vector of the intelligent reflector. This allows the intelligent reflector in the electromagnetic stealth system to eliminate or cancel the reflection signals from all radar echoes and cross-links on the target aircraft surface, achieving near-complete electromagnetic stealth.

[0174] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0175] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0176] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0177] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0178] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0179] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0180] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0181] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0182] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0183] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0184] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A method for designing an intelligent reflective surface, characterized in that, A target aircraft is applied to an electromagnetic stealth system, wherein the electromagnetic stealth system includes the target aircraft, the surface of the target aircraft includes a smart reflective surface and a stealth material surface, the smart reflective surface and the stealth material surface are located on the same target surface, and the method includes: Based on the first number of intelligent reflective units on the intelligent reflective surface, the second number of absorbing units on the stealth material surface, the third number of antennas on the radar, and the two-dimensional angle of arrival and two-dimensional angle of departure of the signal between the target surface and the radar, the radar array response vector of the radar, the reflective surface array response vector of the intelligent reflective surface, and the material array response vector of the stealth material surface are obtained; based on the reflective surface array response vector and the material array response vector, the first cascaded array response vector of the intelligent reflective surface and the second cascaded array response vector of the stealth material surface are obtained; based on the received beamforming vector of the radar, The receiving beamforming gain of the radar is obtained by using the path gain of the radar reaching the target surface and the radar array response vector; the transmitting beamforming gain of the radar is obtained by using the transmitting beamforming vector of the radar, the path gain, and the radar array response vector; the cross-link beamforming gain between any two radars is obtained by using the receiving beamforming gain and the transmitting beamforming gain; a first joint response matrix is ​​obtained by using the first cascaded array response vector and the cross-link beamforming gain; and a second joint response matrix is ​​obtained by using the second cascaded array response vector and the cross-link beamforming gain. A target optimization function is constructed based on the equivalent reflection vector of the stealth material surface, the first joint response matrix, and the second joint response matrix, and the regularization parameters are obtained by solving the target optimization function. The reflection phase shift vector of the smart reflective surface is calculated based on the regularization parameter, the equivalent reflection vector, the first response joint matrix, and the second response joint matrix. The equivalent reflection vector is expressed as: in, This represents the equivalent reflection phase shift of the stealth material surface. Indicates absorption efficiency. N2 represents the number of wave-absorbing units on the surface of the stealth material.

2. The intelligent reflective surface design method according to claim 1, characterized in that, The process of obtaining the radar array response vector of the radar, the reflector array response vector of the smart reflector, and the material array response vector of the stealth material surface based on the first number of smart reflector units on the smart reflector surface, the second number of radar-absorbing units on the stealth material surface, the third number of antennas on the radar, and the two-dimensional angle of arrival and two-dimensional angle of departure of the signal between the target surface and the radar includes: The radar array response vector is obtained based on the third quantity and the two-dimensional departure angle; The response vector of the reflective surface array is obtained based on the first quantity and the two-dimensional angle of arrival; The material array response vector is obtained based on the second quantity and the two-dimensional angle of arrival.

3. The intelligent reflective surface design method according to claim 1, characterized in that, The step of obtaining the first cascaded array response vector of the smart reflective surface and the second cascaded array response vector of the stealth material surface based on the reflective surface array response vector and the material array response vector includes: Obtain the response vector of the first reflector array corresponding to the current radar, and the response vectors of the second reflector arrays corresponding to other radars; The first cascaded array response vector is obtained based on the first reflective surface array response vector and the second reflective surface array response vector; Obtain the first material array response vector corresponding to the current radar, and the second material array response vectors corresponding to other radars; The second cascaded array response vector is obtained based on the first material array response vector and the second material array response vector.

4. The intelligent reflective surface design method according to any one of claims 1 to 3, characterized in that, The step of constructing the objective optimization function based on the equivalent reflection vector of the stealth material surface, the first joint response matrix, and the second joint response matrix includes: A first objective function is constructed based on the regularization parameter, the equivalent reflection vector, the first joint response matrix, and the second joint response matrix; A reflection vector function is constructed based on the regularization parameter, the equivalent reflection vector, the first response joint matrix, and the second response joint matrix. The target optimization function is obtained based on the first objective function and the reflection vector function.

5. The intelligent reflective surface design method according to claim 4, characterized in that, The process of solving the objective optimization function to obtain the regularization parameters includes: Minimizing the first objective function yields the first constraint function; A second constraint function is obtained by making the reflection vector function less than or equal to the maximum reflection amplitude of the intelligent reflection unit; A one-dimensional search algorithm is used to find the regularization parameter in the positive real number field that satisfies the first constraint function and the second constraint function.

6. An aircraft in an electromagnetic stealth system, characterized in that, include: The surface of the aircraft includes a smart reflective surface and a stealth material surface, the smart reflective surface and the stealth material surface being located on the same target surface; the reflection phase shift vector of the smart reflective surface is obtained according to the smart reflective surface design method as described in any one of claims 1 to 5.

7. An electronic device, characterized in that, The electronic device includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the intelligent reflective surface design method according to any one of claims 1 to 5.

8. A storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the intelligent reflective surface design method according to any one of claims 1 to 5.

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