MIMO radar communication integrated waveform design method and system using frequency spectrum amplitude to implant information

Abstract

The invention discloses an MIMO radar communication integrated waveform design method and system using frequency spectrum amplitude to implant information, and belongs to the technical field of radar systems and radar signal processing. The method comprises the following steps: establishing a detection waveform optimization model based on a power matching criterion according to priori knowledge of a radar target distribution airspace; according to a communication information implantation rule, determining an expected frequency spectrum amplitude of a synthetic signal of an MIMO array transmitted waveform in the direction of a communication receiver, and establishing a communication waveform optimization model based on error energy constraint on this basis; combining the two models to establish an MIMO radar communication integrated waveform relaxation optimization model; solving the dual-function integrated waveform optimization model under the constant modulus constraint based on a loop algorithm and an MM algorithm; and the communication receiver decodes the synthesized signal based on a frequency spectrum amplitude segmentation summation criterion to complete communication information transmission with the multifunctional electronic information system.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar system and radar signal processing, and in particular relates to a MIMO radar communication integrated waveform design method and system using spectrum amplitude to implant information. Background Art

[0002] With the continuous development of information technology, the performance of modern electronic information equipment has been greatly improved, and the demands of various users are also increasing, which has led to a sharp increase in the number of electronic information equipment in a limited space and an extremely complex electromagnetic environment. The most prominent problem is that the operating frequency bands of radar, communication, interference and other equipment overlap with each other, and the phenomenon of unintentional interference is becoming more and more serious. How to solve the spectrum compatibility problem between electronic equipment with different uses is imminent.

[0003] The traditional methods of frequency division, spatial division, and time division will more or less restrict the performance of radar, communication and other equipment. Therefore, it is of great significance to study the dual-function electronic information system that uses the same platform, the same equipment, and the same spectrum resources to simultaneously complete target detection and communication information transmission. It is not only an important measure to solve the electromagnetic spectrum congestion between different devices, but also a strong support for improving the comprehensive capabilities of electronic information systems.

[0004] The premise of realizing the dual functions of radar communication is to design an integrated detection waveform with excellent performance. The existing mainstream design methods include: amplitude control method, phase control method, sparse array element selection method, amplitude-phase joint optimization method, synthetic signal direct matching method, etc. These methods have improved the performance of the integrated waveform to varying degrees, but there are still some deficiencies in the bit error rate of communication information transmission, because the ability to suppress the thermal noise of the receiver is not strong. Summary of the invention

[0005] To solve the above problems, the present invention uses the MIMO array as a platform and the expected pattern matching as a criterion for radar, and proposes a radar communication integrated waveform design method and system that uses spectrum amplitude to implant information. The present invention further reduces the transmission bit error rate of communication information without significantly weakening the radar detection performance, and effectively improves the transmission performance of communication information.

[0006] The first aspect of the present invention provides a MIMO radar communication integrated waveform design method using spectrum amplitude implantation information, the method comprising:

[0007] Step S1, according to the prior knowledge of the radar target distribution space, a detection waveform optimization model is established based on the power matching criterion;

[0008] Step S2, determining the expected spectrum amplitude of the synthesized signal of the MIMO array transmission waveform in the direction of the communication receiver according to the communication information implantation rule;

[0009] Step S3, establishing a communication waveform optimization model based on error energy constraints according to the expected spectrum amplitude of the synthetic signal in the communication receiver direction;

[0010] Step S4, establishing a MIMO radar communication integrated waveform relaxation optimization model;

[0011] Step S5, solving the dual-function integrated waveform optimization model under constant modulus constraints based on the loop algorithm and the MM algorithm;

[0012] Step S6: The communication receiver decodes the synthesized signal based on the spectrum amplitude segment summation criterion to complete the communication information transmission with the multifunctional electronic information system.

[0013] In step S1:

[0014] The transmit waveform matrix of the MIMO array is Among them, s n =[s1(n),s2(n),…,s M (n)] T represents the transmission waveform of the nth (n=1, 2, ..., N) sub-pulse, where M is the number of transmitting array elements and N is the number of sub-pulses;

[0015] The combined signal power of the MIMO array at the far-field space θ is P(θ) = ||a H (θ)S|| 2 ;in,(·) T represents the transpose of a matrix or vector, (·) H represents the conjugate transpose of a matrix or vector, ||·|| 2 represents the sum of the squares of all elements of the vector, a(θ)=[1,e jπsinθ ,…,e jπ(M-1)sinθ ] T represents the launch steering vector in the θ direction;

[0016] According to the spatial synthesis power of the transmission waveform and the expected transmission pattern, the MIMO array detection waveform optimization model is established:

[0017]

[0018] st|S(m,n)|=1,m=1,2,...,M,n=1,2,...,N

[0019] in, Represents θ k The launch steering vector in the direction, θ k represents the kth discretized angle in the space, and the number of discretized angles in the entire space is K, w k is θk The weighting coefficient of the transmission power matching error in the direction, is the radar pattern expected by the MIMO array, α is the scale factor used to compromise the mismatch between the expected pattern and the actual pattern, S(m,n) represents the element in the mth row and nth column of the matrix S, and |·| represents the modulus value.

[0020] In step S2:

[0021] One bit of information is transmitted with the amplitude spectrum of N1 frequency points, and the spectrum of the entire composite signal is divided into N / N1 parts;

[0022] The expected spectrum amplitude is divided into three levels. The spectrum amplitude value of the first N / N1 reference frequency points is σ1=5. For the spectrum amplitude of the subsequent frequency points, if 0 is transmitted, the spectrum amplitude value of the corresponding N / N1 frequency points is σ2=10. -6 ; If 1 is transmitted, the spectrum amplitude value of the corresponding N / N1 frequency points is σ3=10;

[0023] The expected spectrum amplitude of the synthesized signal of the MIMO array in the direction of the communication receiver during the radar pulse is

[0024] In step S3:

[0025] The space self-communication receiver is located in the far field direction θ of the MIMO array c The composite signal at the communication receiver is Among them, a c is the corresponding direction steering vector;

[0026] Perform Fourier transform on the synthesized signal to obtain its spectrum in, p represents the multiple of the fundamental frequency;

[0027] According to the synthetic signal spectrum, the communication waveform optimization model of the MIMO array is established:

[0028]

[0029] |S(m,n)|=1,m=1,2,…,M,n=1,2,…,N

[0030] Where γ>0 is a scaling factor used to compromise the matching error between the spectrum amplitude of the synthesized signal and the expected spectrum amplitude; η p It represents the weighting coefficient of the matching error of the pth frequency point of the spectrum amplitude of the signal received by the communication device.

[0031] In step S4:

[0032] By combining the MIMO array detection waveform optimization model and the communication waveform optimization model, an integrated waveform optimization model with dual functions of detection and communication is obtained:

[0033]

[0034] st|S(m,n)|=1,m=1,2,...,M,n=1,2,...,N

[0035] Among them, 0≤β≤1 is a scaling factor, which is used to compromise the radar detection performance and communication information transmission performance. When β=0, only the communication performance is considered, and when β=1, only the radar performance is considered;

[0036] The transmit waveform matrix is ​​vectorized, and the synthetic signal spectrum amplitude matching non-convex constraint is transformed into a complex fitting error constraint, and a relaxed integrated waveform optimization model is established:

[0037]

[0038] st|s(l)|=1,l=1,2,…,MN

[0039] Where s = vec T (S), vec(·) means the matrix is ​​straightened by columns; I N is the N-dimensional unit matrix, represents the Kron product, (·)* represents the conjugate of a matrix or vector; is the phase factor, which is an auxiliary variable introduced to simplify the problem solving.

[0040] In step S5, the integrated waveform optimization model is a non-convex optimization problem with multiple variables, and a loop algorithm is used to solve the problem, specifically including:

[0041] Step S5-1, s, γ and When certain, update α:

[0042]

[0043] Step S5-2: When s, γ and α are constant, update

[0044]

[0045] Among them, angle(·) represents the phase;

[0046] Step S5-3, s, When and α are constant, update γ:

[0047]

[0048] Step S5-4, γ, When and α are constant, update s:

[0049] Construct an upper bound function and relax it into a quadratic optimization problem about s:

[0050]

[0051] st|s(l)|=1,l=1,2,…,MN

[0052] in, s q is the iteration value of s at step q, c1 is a fixed constant, Re(·) means taking the real part;

[0053] The MM algorithm is used to relax the quadratic optimization problem into a linear optimization problem under equality constraints:

[0054]

[0055] st|s(l)|=1,l=1,2,…,MN

[0056] Where u=(L B ′-B′+MNκ)(s q ) H , L B′ =diag(|B′|e), diag(·) represents vector matrixization, e is a vector of all 1s of the corresponding dimension; v = λ max (s q ) H -P(s q )H+γq,

[0057] γ、 When and α are constant, the optimal value of s is

[0058] Let q = q + 1 and repeat the calculation Until the change value of the original objective function of the integrated waveform meets the preset threshold;

[0059] Step S5-5, loop iteratively step S5-1 to S5-4, alternately solving γ, α and s; until the change value of the original objective function meets the preset threshold, the iteration is stopped to obtain the optimal transmission waveform for MIMO radar communication integration.

[0060] In step S6,

[0061] The spectrum of the synthetic signal intercepted by the communication receiver is Among them, n p is the spectrum of Gaussian white noise inside the receiver;

[0062] Record the start time of the MIMO array transmitting signal, and use the known spatial relationship between the MIMO platform and the communication receiver to calculate the signal starting time of the communication receiver;

[0063] Extract the complete communication receiving signal according to the known pulse code length, perform Fourier transform on it, normalize the frequency points to N, and then obtain the spectrum amplitude;

[0064] According to the known coding rules, the spectrum amplitude is divided into N / N1 parts with N1 points as one segment;

[0065] The absolute sum of the amplitudes of the subsequent N / N1-1 partial spectrum is compared with the absolute sum of the amplitudes of the first partial spectrum; if it is greater than the absolute sum of the amplitudes of the first partial spectrum, it is decoded as 1; otherwise, it is decoded as 0.

[0066] A second aspect of the present invention discloses a MIMO radar communication integrated waveform design system using spectrum amplitude implantation information, the system comprising a processing unit, the processing unit being configured to perform the following steps:

[0067] Step S1, according to the prior knowledge of the radar target distribution space, a detection waveform optimization model is established based on the power matching criterion;

[0068] Step S2, determining the expected spectrum amplitude of the synthesized signal of the MIMO array transmission waveform in the direction of the communication receiver according to the communication information implantation rule;

[0069] Step S3, establishing a communication waveform optimization model based on error energy constraints according to the expected spectrum amplitude of the synthetic signal in the communication receiver direction;

[0070] Step S4, establishing a MIMO radar communication integrated waveform relaxation optimization model;

[0071] Step S5, solving the dual-function integrated waveform optimization model under constant modulus constraints based on the loop algorithm and the MM algorithm;

[0072] Step S6: The communication receiver decodes the synthesized signal based on the spectrum amplitude segment summation criterion to complete the communication information transmission with the multifunctional electronic information system.

[0073] The third aspect of the present invention discloses an electronic device. The electronic device includes a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the steps of the MIMO radar communication integrated waveform design method using spectrum amplitude implantation information described in the first aspect of the present disclosure are implemented.

[0074] The fourth aspect of the present invention discloses a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the MIMO radar communication integrated waveform design method using spectrum amplitude implantation information described in the first aspect of the present disclosure.

[0075] In summary, the beneficial effects of the present invention are as follows:

[0076] 1. The radar communication integrated waveform designed based on the MIMO array of the present invention enables the MIMO array to realize transmission power focusing in the specified desired airspace, synthesize the required communication signal in the direction of the communication receiver to realize communication information transmission, and can simultaneously ensure the target detection capability and covert communication capability of our electronic information system in a complex electromagnetic environment.

[0077] 2. Compared with the existing integrated waveform design method, the present invention makes full use of the characteristics of independent distribution of Gaussian white noise and signal. Based on the uniformity of the noise power spectrum and its weak influence on the amplitude shape of the signal spectrum, a strategy of using the spectrum amplitude to implant communication information is proposed, which can reduce the bit error rate of communication information transmission by about an order of magnitude.

[0078] 3. The encoding method of the present invention is very flexible and can reasonably adjust variables such as the total length of a single pulse code and the number of coding bits according to actual application requirements to achieve a compromise between the communication information transmission rate and the bit error rate.

[0079] 4. The directional pattern matching model, communication information implantation strategy and optimization problem solving method proposed in the present invention can provide reference for the optimization design of the multifunctional integrated waveform of detection and jamming. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0081] Figure 1 The present invention is a flow chart of the design of the transmission waveform;

[0082] Figure 2 It is a schematic diagram of synthetic signal decoding based on spectrum amplitude segmentation summation;

[0083] Figure 3 To provide a radar transmission pattern synthesized by using the waveform optimized by the present invention;

[0084] Figure 4 A spectrum amplitude diagram of a communication signal synthesized by using the waveform optimized by the present invention;

[0085] Figure 5 The figure is a schematic diagram showing the variation of the bit error rate of communication information transmission obtained by using the encoding / decoding strategy proposed by the present invention with the signal-to-noise ratio. DETAILED DESCRIPTION

[0086] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0087] Based on the traditional MIMO radar transmitting waveform design, the present invention further considers the dual functions of target detection and communication information transmission, and proposes a radar communication integrated waveform design method and system that uses spectrum amplitude to implant information. By reasonably designing the transmitting waveform, the MIMO array can achieve transmitting power focusing in the specified desired airspace while synthesizing the required communication signal in the direction of the communication receiver. Through information decoding, effective information transmission with one's own communication equipment can be completed, which greatly improves the target detection capability and covert communication capability of our electronic information system.

[0088] The present invention firstly establishes a detection waveform optimization model based on the power matching criterion according to the prior knowledge of the radar target distribution airspace; secondly, according to the communication information implantation rule, the expected spectrum amplitude of the synthetic signal of the MIMO array transmission waveform in the direction of the communication receiver is determined, and on this basis, a communication waveform optimization model based on error energy constraints is established; thirdly, combining the above two models, and for the convenience of subsequent solution, a MIMO radar communication integrated waveform relaxation optimization model is established; fourthly, based on the cyclic algorithm and the Majorization-minimization (MM) algorithm, the dual-function integrated waveform optimization model under the constant modulus constraint is solved; finally, the communication receiver decodes the synthetic signal based on the spectrum amplitude segmentation summation criterion to complete the communication information transmission with the multifunctional electronic information system. This method enables the MIMO array to realize the transmission power focusing in the specified expected airspace while synthesizing the required communication signal in the direction of the communication receiver. Through information decoding, effective information transmission with one's own communication equipment can be completed, and it has strong robustness to Gaussian white noise, which greatly improves the target detection capability and covert communication capability of our electronic information system.

[0089] The first aspect of the present invention provides a MIMO radar communication integrated waveform design method using spectrum amplitude implantation information, the method comprising:

[0090] 1. According to the prior knowledge of radar target distribution space, a detection waveform optimization model is established based on the power matching criterion.

[0091] (1) Let the transmit waveform matrix of the MIMO array be where s n =[s1(n),s2(n),…,s M (n)] T represents the transmitted waveform of the nth (n = 1, 2, ..., N) sub-pulse, M is the number of transmitting array elements, N is the number of sub-pulses, and the composite signal power of the MIMO array at the far-field space θ is given as:

[0092] P(θ)=||a H (θ)S|| 2

[0093] in,(·) T represents the transpose of a matrix or vector, (·) H represents the conjugate transpose of a matrix or vector, ||·|| 2 represents the sum of the squares of all elements of the vector, a(θ)=[1,e jπsinθ ,…,e jπ(M-1)sinθ ] T represents the launch steering vector in the θ direction.

[0094] (2) According to the spatial synthesis power of the transmission waveform and the expected transmission pattern, the MIMO array detection waveform optimization model is established as follows:

[0095]

[0096] st|S(m,n)|=1,m=1,2,…,M,n=1,2,…,N

[0097] in, Represents θ k The launch steering vector in the direction, θ k represents the kth discretized angle in the space, and the number of discretized angles in the entire space is K, w k is θ k The weighting coefficient of the transmission power matching error in the direction, is the radar pattern expected by the MIMO array, α is the scale factor used to compromise the mismatch between the expected pattern and the actual pattern, S(m,n) represents the element in the mth row and nth column of the matrix S, and |·| represents the modulus value.

[0098] 2. According to the communication information implantation rules, determine the expected spectrum amplitude of the synthetic signal of the MIMO array transmission waveform in the direction of the communication receiver. Let the amplitude spectrum of N1 frequency points transmit one bit of information, and the spectrum of the entire synthetic signal can be divided into N / N1 (generally an integer) parts. Divide the expected spectrum amplitude into three levels, and the spectrum amplitude value of the first N / N1 reference frequency points is σ1=5; for the spectrum amplitude of subsequent frequency points, if "0" is to be transmitted, let the spectrum amplitude value of the corresponding N / N1 frequency points be σ2=10 -6 ; If "1" is to be transmitted, the spectrum amplitude value of the corresponding N / N1 frequency points is set to σ3 = 10. According to this rule, the expected spectrum amplitude of the synthesized signal of the MIMO array in the direction of the communication receiver during a certain radar pulse is recorded as

[0099] 3. According to the expected spectrum amplitude of the synthetic signal in the direction of the communication receiver, a communication waveform optimization model based on error energy constraints is established.

[0100] (1) Assume that the space self-communication receiver is located in the far-field direction θ of the MIMO array c The composite signal at the communication receiver is Among them, a c is the corresponding direction steering vector. The spectrum of the synthesized signal can be obtained by Fourier transform:

[0101]

[0102] in, p represents the multiple of the fundamental frequency.

[0103] (2) According to the spectrum of the synthetic signal, the communication waveform optimization model of the MIMO array is established as follows:

[0104]

[0105] |S(m,n)|=1,m=1,2,…,M,n=1,2,…,N

[0106] Where γ>0 is a scaling factor, which is used to compromise the matching error between the spectrum amplitude of the synthesized signal and the expected spectrum amplitude; η p It represents the weighting coefficient of the matching error of the pth frequency point of the spectrum amplitude of the received signal of the communication device, and its effect is similar to w k similar.

[0107] 4. To facilitate subsequent solutions, an integrated waveform relaxation optimization model for MIMO radar communication is established.

[0108] (1) By combining the MIMO array detection waveform optimization model and the communication waveform optimization model, an integrated waveform optimization model with dual detection and communication functions can be obtained:

[0109]

[0110] st|S(m,n)|=1,m=1,2,…,M,n=1,2,…,N

[0111] Among them, 0≤β≤1 is a scaling factor, which is used to compromise between radar detection performance and communication information transmission performance. When β=0, only communication performance is considered, and when β=1, only radar performance is considered.

[0112] (2) To facilitate subsequent derivation and solution, the transmit waveform matrix needs to be vectorized, and the non-convex constraint of synthetic signal spectrum amplitude matching needs to be transformed into a complex fitting error constraint. Based on this, a relaxed integrated waveform optimization model can be established:

[0113]

[0114] st|s(l)|=1,l=1,2,…,MN

[0115] Where s = vec T (S), vec(·) means the matrix is ​​straightened by columns; I N is the N-dimensional unit matrix, represents the Kron product, (·) * Represents the conjugate of a matrix or vector; is the phase factor, which is an auxiliary variable introduced to simplify the problem solving.

[0116] 5. Solve the dual-function integrated waveform optimization model under constant modulus constraints based on the loop algorithm and MM algorithm.

[0117] The integrated waveform optimization model is a non-convex optimization problem with multiple variables. The problem can be solved by a loop algorithm. It consists of five parts, which are described in detail as follows:

[0118] (1)s, γ and When certain, update α:

[0119]

[0120] (2) When s, γ and α are constant, update

[0121]

[0122] Here, angle(·) represents the phase.

[0123] (3)s, When and α are constant, update γ:

[0124]

[0125] (4) γ, When and α are constant, update s:

[0126] Since the original formula is a quartic optimization problem about s, it is difficult to solve it directly. The patent of this invention constructs a suitable upper bound function to relax it into a quadratic optimization problem about s. The model is as follows:

[0127]

[0128] st|s(l)|=1,l=1,2,…,MN

[0129] in, s q is the iteration value of s at step q, c1 is a fixed constant, and Re(·) represents the real part. However, the above model still belongs to a non-convex optimization problem. Therefore, the present invention uses the MM algorithm to relax it into a linear optimization problem under an equality constraint:

[0130]

[0131] st|s(l)|=1,l=1,2,…,MN

[0132] The above formula ignores fixed constants that are irrelevant to optimization, u=(L B′ -B′+MNκ)(s q ) H , L B′ -diag(|B′|e), diag(·) represents vector matrixization, e is the all-one vector of the corresponding dimension; v = λ max (s q ) H -P(s q ) H +γq, According to the above formula, it is easy to obtain γ, When and α are constant, the optimal value of s is Let q = q + 1 and repeat the calculation Until the change value of the original objective function of the integrated waveform meets the preset threshold.

[0133] (5) Iterate (1) to (4) and alternately solve γ, α and s are adjusted until the change value of the original objective function meets the preset threshold, and the iteration is stopped to obtain the optimal transmission waveform for MIMO radar communication integration.

[0134] 6. The communication receiver decodes the synthesized signal based on the spectrum amplitude segment summation criterion to complete the communication information transmission with the multifunctional electronic information system. Assume that the spectrum of the synthesized signal intercepted by the communication receiver is: Among them, n p is the spectrum of Gaussian white noise inside the receiver. First, record the starting time of the MIMO array transmitting signal, and use the known spatial relationship between the MIMO platform and the communication receiver to calculate the signal starting time of the communication receiver. Secondly, extract the complete communication receiving signal according to the known pulse code length, and perform Fourier transform (normalized frequency points are N) on it to obtain the spectrum amplitude. Thirdly, according to the known coding rules, divide the spectrum amplitude into N / N1 parts according to N1 points as a segment. Finally, compare the absolute sum of the spectrum amplitudes of the following N / N1-1 parts with the absolute sum of the spectrum amplitudes of the first part. If it is greater than the absolute sum of the spectrum amplitudes of the first part, it is decoded as "1", otherwise it is decoded as "0", such as Figure 2 shown.

[0135] Simulation Example

[0136] Simulation conditions: The number of array elements in the MIMO array is M = 10, the code length of the waveform transmitted by each array element is N = 128, the desired spatial domain is specified as [-20°, 20°], the entire spatial domain is discretized into 181 grid points, the discretization interval is 1°, and the relative direction between the spatial self-communication receiver and the MIMO array is set to -45°. Set w k =1, k = 1, 2, ..., K, η p =1, p=0,1,…,N-1, β=10 -3 , N1=16When the change of the objective function value in adjacent iteration steps is less than 10 -4 When , the iteration stops and the initial waveform is generated randomly.

[0137] Figure 3 The radar emission pattern of the waveform synthesis optimized by the present invention is given, such as Figure 3 As shown in the figure, the optimized transmission pattern achieves power focusing in the specified desired airspace, which effectively improves the power utilization compared to the traditional orthogonal MIMO radar, can provide a higher signal-to-noise ratio for echo signal processing, and is more effective in target detection and parameter estimation.

[0138] Figure 4 The spectrum amplitude of the synthesized signal of the optimized waveform in the communication receiver direction of the present invention is given, such as Figure 4As shown in the figure, both the spectrum amplitude of the synthetic signal and the spectrum amplitude of the signal actually received by the communication receiver (the signal-to-noise ratio is 5dB) are effectively fitted with the expected spectrum amplitude, which lays a favorable foundation for the subsequent interpretation of communication signal information.

[0139] Figure 5 The variation of the bit error rate of communication information transmission obtained after the optimized waveform of the present invention is decoded at the communication receiver with the signal-to-noise ratio (the signal-to-noise ratio is -20dB to 20dB, the number of discrete points is 21, and the number of equivalent Monte Carlo experiments is 40000) is given as follows: Figure 5 As shown, with the increase of the signal-to-noise ratio, the bit error rate of communication information transmission is rapidly decreasing. When the signal-to-noise ratio is greater than 4dB, the bit error rate is already lower than 1%, which is about 0.4%; when the signal-to-noise ratio is greater than 10dB, the bit error rate can basically be controlled to below 0.01%, which shows that the communication information implantation method proposed in the present invention is more robust to noise.

[0140] comprehensive Figure 3-Figure 5 It can be seen that the MIMO radar communication integrated waveform design method and system proposed in the present invention utilizes spectrum amplitude to implant information, so that the MIMO array can realize transmission power focusing in the specified desired airspace, synthesize the required communication signal in the direction of the communication receiver, and realize effective information transmission with one's own communication equipment through information decoding, which greatly enhances the target detection capability and covert communication capability of our electronic information system.

[0141] A second aspect of the present invention discloses a MIMO radar communication integrated waveform design system using spectrum amplitude implantation information, the system comprising a processing unit, the processing unit being configured to perform the following steps:

[0142] Step S1, according to the prior knowledge of the radar target distribution space, a detection waveform optimization model is established based on the power matching criterion;

[0143] Step S2, determining the expected spectrum amplitude of the synthesized signal of the MIMO array transmission waveform in the direction of the communication receiver according to the communication information implantation rule;

[0144] Step S3, establishing a communication waveform optimization model based on error energy constraints according to the expected spectrum amplitude of the synthetic signal in the communication receiver direction;

[0145] Step S4, establishing a MIMO radar communication integrated waveform relaxation optimization model;

[0146] Step S5, solving the dual-function integrated waveform optimization model under constant modulus constraints based on the loop algorithm and the MM algorithm;

[0147] Step S6: The communication receiver decodes the synthesized signal based on the spectrum amplitude segment summation criterion to complete the communication information transmission with the multifunctional electronic information system.

[0148] The third aspect of the present invention discloses an electronic device. The electronic device includes a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the steps of the MIMO radar communication integrated waveform design method using spectrum amplitude implantation information described in the first aspect of the present disclosure are implemented.

[0149] The fourth aspect of the present invention discloses a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the MIMO radar communication integrated waveform design method using spectrum amplitude implantation information described in the first aspect of the present disclosure.

[0150] In summary, the beneficial effects of the present invention are as follows:

[0151] 1. The radar communication integrated waveform designed based on the MIMO array of the present invention enables the MIMO array to realize transmission power focusing in the specified desired airspace, synthesize the required communication signal in the direction of the communication receiver to realize communication information transmission, and can simultaneously ensure the target detection capability and covert communication capability of our electronic information system in a complex electromagnetic environment.

[0152] 2. Compared with the existing integrated waveform design method, the present invention makes full use of the characteristics of independent distribution of Gaussian white noise and signal. Based on the uniformity of the noise power spectrum and its weak influence on the amplitude shape of the signal spectrum, a strategy of using the spectrum amplitude to implant communication information is proposed, which can reduce the bit error rate of communication information transmission by about an order of magnitude.

[0153] 3. The encoding method of the present invention is very flexible and can reasonably adjust variables such as the total length of a single pulse code and the number of coding bits according to actual application requirements to achieve a compromise between the communication information transmission rate and the bit error rate.

[0154] 4. The directional pattern matching model, communication information implantation strategy and optimization problem solving method proposed in the present invention can provide reference for the optimization design of the multifunctional integrated waveform of detection and jamming.

[0155] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above-mentioned embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A MIMO radar communication integrated waveform design method using spectrum amplitude implantation information, characterized in that: The method comprises: Step S1, according to the prior knowledge of the radar target distribution space, a detection waveform optimization model is established based on the power matching criterion; Step S2, determining the expected spectrum amplitude of the synthesized signal of the MIMO array transmission waveform in the direction of the communication receiver according to the communication information implantation rule; Step S3, establishing a communication waveform optimization model based on error energy constraints according to the expected spectrum amplitude of the synthetic signal in the communication receiver direction; Step S4, establishing a MIMO radar communication integrated waveform relaxation optimization model; Step S5, solving the dual-function integrated waveform optimization model under constant modulus constraints based on the loop algorithm and the MM algorithm; Step S6: The communication receiver decodes the synthesized signal based on the spectrum amplitude segment summation criterion to complete the communication information transmission with the multifunctional electronic information system.

2. The MIMO radar communication integrated waveform design method using spectrum amplitude implantation information according to claim 1 is characterized in that: In step S1: The transmit waveform matrix of the MIMO array is Among them, s n =[s1(n),s2(n),…,s M (n)] T represents the transmission waveform of the nth (n=1, 2, ..., N) sub-pulse, where M is the number of transmitting array elements and N is the number of sub-pulses; The combined signal power of the MIMO array at the far-field space θ is P(θ) = ||a H (θ)S|| 2 ;in,(·) T represents the transpose of a matrix or vector, (·) H represents the conjugate transpose of a matrix or vector, ||·|| 2 represents the sum of the squares of all elements of the vector, a(θ)=[1,e jπsinθ ,…,e jπ(M-1)sinθ ] T represents the launch steering vector in the θ direction; According to the spatial synthesis power of the transmission waveform and the expected transmission pattern, the MIMO array detection waveform optimization model is established: st|S(m,n)|=1,m=1,2,…,M,n=1,2,…,N in, Represents θ k The launch steering vector in the direction, θ k Indicates the space k The number of discretized angles in the entire space is K, w k is θ k The weighting coefficient of the transmission power matching error in the direction, is the radar pattern expected by the MIMO array, α is the scale factor used to compromise the mismatch between the expected pattern and the actual pattern, S(m,n) represents the element in the mth row and nth column of the matrix S, and |·| represents the modulus value.

3. The MIMO radar communication integrated waveform design method using spectrum amplitude implantation information according to claim 2 is characterized in that: In step S2: One bit of information is transmitted with the amplitude spectrum of N1 frequency points, and the spectrum of the entire composite signal is divided into N / N1 parts; The expected spectrum amplitude is divided into three levels. The spectrum amplitude value of the first N / N1 reference frequency points is σ1=5. For the spectrum amplitude of the subsequent frequency points, if 0 is transmitted, the spectrum amplitude value of the corresponding N / N1 frequency points is σ2=10. -6 ; If 1 is transmitted, the spectrum amplitude value of the corresponding N / N1 frequency points is σ3=10; The expected spectrum amplitude of the synthesized signal of the MIMO array in the direction of the communication receiver during the radar pulse is 4. The MIMO radar communication integrated waveform design method using spectrum amplitude implantation information according to claim 3 is characterized in that: In step S3: The space self-communication receiver is located in the far field direction θ of the MIMO array c The composite signal at the communication receiver is Among them, a c is the corresponding direction steering vector; Perform Fourier transform on the synthesized signal to obtain its spectrum in, p represents the multiple of the fundamental frequency; According to the synthetic signal spectrum, the communication waveform optimization model of the MIMO array is established: |S(m,n)|=1,m=1,2,…,M,n=1,2,…,N Where γ>0 is a scaling factor used to compromise the matching error between the spectrum amplitude of the synthesized signal and the expected spectrum amplitude; η p It represents the weighting coefficient of the matching error of the pth frequency point of the spectrum amplitude of the signal received by the communication device.

5. The MIMO radar communication integrated waveform design method using spectrum amplitude implantation information according to claim 4 is characterized in that: In step S4: By combining the MIMO array detection waveform optimization model and the communication waveform optimization model, an integrated waveform optimization model with dual functions of detection and communication is obtained: st|S(m,n)|=1,m=1,2,…,M,n=1,2,…,N Among them, 0≤β≤1 is a scaling factor, which is used to compromise the radar detection performance and communication information transmission performance. When β=0, only the communication performance is considered, and when β=1, only the radar performance is considered; The transmit waveform matrix is ​​vectorized, and the synthetic signal spectrum amplitude matching non-convex constraint is transformed into a complex fitting error constraint, and a relaxed integrated waveform optimization model is established: st|s(l)|=1,l=1,2,…,MN Where s = vec T (S), vec(·) means the matrix is ​​straightened by columns; I N is the N-dimensional unit matrix, represents the Kron product, (·) * Represents the conjugate of a matrix or vector; is the phase factor, which is an auxiliary variable introduced to simplify the problem solving.

6. The method for designing an integrated waveform for MIMO radar communication using spectrum amplitude information implantation according to claim 5, characterized in that: In step S5, the integrated waveform optimization model is a non-convex optimization problem with multiple variables, and a loop algorithm is used to solve the problem, specifically including: Step S5-1, s, γ and When certain, update α: Step S5-2: When s, γ and α are constant, update Among them, angle(·) represents the phase; Step S5-3, s, When and α are constant, update γ: Step S5-4, γ, When and α are constant, update s: Construct an upper bound function and relax it into a quadratic optimization problem about s: st|s(l)|=1,l=1,2,…,MN in, s q is the iteration value of s at step q, c1 is a fixed constant, Re(·) means taking the real part; The MM algorithm is used to relax the quadratic optimization problem into a linear optimization problem under equality constraints: st|s(l)|=1,l=1,2,…,MN Where u=(L B′ -B′+MNκ)(s q ) H , L B′ =diag(B′|e), where diag(·) represents vector matrixing, and e is a vector of all 1s of the corresponding dimension; v = λ max (s q ) H -P(s q ) H +γq, γ, When and α are constant, the optimal value of s is Let q = q + 1 and repeat the calculation Until the change value of the original objective function of the integrated waveform meets the preset threshold; Step S5-5, loop iteratively step S5-1 to S5-4, alternately solving γ, α and s; until the change value of the original objective function meets the preset threshold, the iteration is stopped to obtain the optimal transmission waveform for MIMO radar communication integration.

7. The MIMO radar communication integrated waveform design method using spectrum amplitude implantation information according to claim 6 is characterized in that: In step S6, The spectrum of the synthetic signal intercepted by the communication receiver is Among them, n p is the frequency spectrum of Gaussian white noise inside the receiver; Record the start time of the MIMO array transmitting signal, and use the known spatial relationship between the MIMO platform and the communication receiver to calculate the signal starting time of the communication receiver; Extract the complete communication receiving signal according to the known pulse code length, perform Fourier transform on it, normalize the frequency points to N, and then obtain the spectrum amplitude; According to the known coding rules, the spectrum amplitude is divided into N / N1 parts with N1 points as one segment; The absolute sum of the amplitudes of the subsequent N / N1-1 partial spectrum is compared with the absolute sum of the amplitudes of the first partial spectrum; if it is greater than the absolute sum of the amplitudes of the first partial spectrum, it is decoded as 1; otherwise, it is decoded as 0.

8. A MIMO radar communication integrated waveform design system using spectrum amplitude implantation information, characterized in that: The system comprises a processing unit configured to perform the following steps: Step S1, according to the prior knowledge of the radar target distribution space, a detection waveform optimization model is established based on the power matching criterion; Step S2, determining the expected spectrum amplitude of the synthesized signal of the MIMO array transmission waveform in the direction of the communication receiver according to the communication information implantation rule; Step S3, establishing a communication waveform optimization model based on error energy constraints according to the expected spectrum amplitude of the synthetic signal in the communication receiver direction; Step S4, establishing a MIMO radar communication integrated waveform relaxation optimization model; Step S5, solving the dual-function integrated waveform optimization model under constant modulus constraints based on the loop algorithm and the MM algorithm; Step S6: The communication receiver decodes the synthesized signal based on the spectrum amplitude segment summation criterion to complete the communication information transmission with the multifunctional electronic information system.

9. An electronic device, characterized in that: The electronic device includes a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the steps of the MIMO radar communication integrated waveform design method using spectrum amplitude implantation information as described in any one of claims 1-7 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, the steps of the MIMO radar communication integrated waveform design method using spectrum amplitude implantation information as described in any one of claims 1 to 7 are implemented.

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