Polarization mimo multi-parameter estimation method and system based on transmit polarization modulation

Abstract

The application belongs to the technical field of radar parameter processing, and discloses a polarization MIMO multi-parameter estimation method and system based on transmission polarization modulation. A polarization multi-input multi-output high-frequency ground wave radar array structure is formed by a transmission end and a receiving end. The transmission end performs transmission polarization modulation on the target signal transmitted by the transmission array element through a polarization phase controller. The receiving end receives the echo data of the target after the transmission polarization modulation, performs pulse compression processing on the echo data, and then reconstructs the echo data. The form of a third-order tensor is constructed, and then the tensor decomposition of the third-order tensor form is performed through an alternating least square method. The polarization parameter joint estimation is performed through a multi-parameter joint estimation signal processing method. The application aims to design a novel high-frequency ground wave radar transmission-receiving array structure and a P-MIMO-HFSWR signal processing method, and realize the multi-parameter high-precision estimation of the sea surface target.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of radar parameter processing, and particularly relates to a polarized MIMO multi-parameter estimation method and system based on transmission polarization modulation. BACKGROUND

[0002] High frequency surface wave radar (HFSWR) works between 3-30MHz, and electromagnetic waves at this frequency can propagate along the sea surface by diffraction, thereby overcoming the limitation of the earth's curvature and realizing over-the-horizon detection. Generally, the maximum detection distance is generally more than 400km, and real-time monitoring of sea surface targets, low-altitude flying targets and marine environment in the exclusive economic zone can be realized. The traditional HFSWR parameter estimation algorithm only uses the space (angle) time (distance) frequency (Doppler) information of the target signal, and does not fully utilize some non-space characteristics contained in the echo signal itself, and the estimation accuracy is difficult to further improve. Polarization information as an inherent vector characteristic of electromagnetic signals is an important information that can be utilized in addition to time domain, frequency domain and space domain information of signals. If a polarization sensitive array is used, not only the time domain and space domain information of the echo signal can be perceived, but also the polarization information of the echo can be perceived, and the polarization information is comprehensively used to improve the parameter estimation performance of the HFSWR. The angle measurement accuracy of the radar is usually related to the array size of the radar. The array size is usually restricted by the working wavelength of the radar, which leads to the difficulty of achieving a good angle estimation performance of the HFSWR. Improving the angle estimation capability of the HFSWR has irreplaceable significance for the promotion and application of HFSWR. The MIMO system HFSWR can expand the original virtual aperture, and can improve the angle resolution capability without increasing the area of the receiving array, and compared with the traditional array HFSWR, the data volume is increased by several times, and the signal-to-noise ratio of the target is improved.

[0003] Through the above analysis, the problems and defects of the prior art are that the polarization information that can be obtained by the HFSWR in target detection is mainly limited to two parameters of polarization tilt angle and polarization difference angle, which is difficult to fully represent the polarization scattering characteristics of the target, which will lead to limited description of the polarization characteristics of the target itself. The estimation performance of the target angle parameter and the polarization parameter is poor due to the restriction of the array structure, which further affects the identification and positioning of the target. SUMMARY

[0004] In order to overcome the problems in the prior art, the application discloses a polarized MIMO multi-parameter estimation method and system based on transmit polarization modulation, and particularly relates to a joint estimation method of polarization parameters and angle parameters of a multi-input multi-output (MIMO) radar based on transmit polarization modulation.

[0005] The technical scheme is as follows: a polarized MIMO multi-parameter estimation method based on transmit polarization modulation, comprising the following steps:

[0006] S1, designing a polarized multi-input multi-output high frequency surface wave radar array structure composed of a transmitting end and a receiving end; wherein the transmitting end modulates the target signal transmitted by the transmitting elements through a polarization phase controller, and the receiving end receives the echo data of the target after transmit polarization modulation, and reconstructs the echo data after pulse compression processing;

[0007] S2, using the reconstructed echo data, constructing a three-order tensor form, and performing tensor decomposition on the three-order tensor form through an alternating least squares method;

[0008] S3, based on the result of tensor decomposition, using a multi-parameter joint estimation signal processing method to perform polarized parameter joint estimation, and outputting the polarized parameter estimation result; the multi-parameter joint estimation signal processing method comprises wave departure direction angle (DOD) estimation, wave arrival direction angle (DOA) estimation and polarization scattering matrix estimation.

[0009] In step S1, the transmitting end is composed of M transmitting elements forming a uniform linear array, each transmitting element is composed of a group of orthogonal electric dipoles, and is distributed parallel to the Y axis and the Z axis, and the polarization state of the transmitting elements is modulated through a polarization phase controller of the transmitting elements;

[0010] The method for modulating the polarization state of the transmitting elements comprises: the transmitting end adopts a linear polarization mode, the transmitting element at the coordinate origin is a reference element, and the transmission polarization inclination angle of the other transmitting elements relative to the reference element has a fixed difference value ;

[0011] The electric field polarization vector of the transmitter reference element is expressed as:

[0012] ;

[0013] In the formula, The electric field polarization vector of the reference element at the transmitting end. The imaginary unit, This is the transpose of the vector. The polarization tilt angle of the reference element at the transmitting end. The polarization phase difference of the reference array element at the transmitting end. constant ;

[0014] No. The electric field polarization vector of each transmitting element is modulated as follows:

[0015] ;

[0016] In the formula, For the first The electric field polarization vector of each transmitting element, The integer index represents any number from 1 to M;

[0017] For matrix transformations, we have:

[0018] ;

[0019] In the formula, This is the Givens rotation matrix;

[0020] Will The consecutive multiplication of three identical matrices is defined as... ,Right now: Then we have: Establish the polarization modulation mode of the remaining array elements relative to the reference array element.

[0021] In step S1, after pulse compression processing of the echo data, echo data reconstruction is performed, including:

[0022] If there are K independent targets in the far field, then the... The expression for the signal received by each antenna is:

[0023] ;

[0024] In the formula, For the first The signal received by each antenna The number of independent targets in the scene. The number of transmitting antennas. For the first The polarization steering vector matrix of each target. For the first The receiver polarization vector of a target, For the first The transmitted signal of each array element For the first The first goal One emission guidance vector element, For the first The first goal One receiving guide vector element, The received Gaussian white noise sequence, The index to be received. The subscript for launch;

[0025] They are defined as follows:

[0026] ;

[0027] ;

[0028] In the formula, For the first The first goal in The phase generated on each transmitting antenna For the first The first goal in The phase excited on each receiving antenna, These are the element spacings at the transmitting and receiving ends, respectively. The first The direction of departure (DOD) and direction of arrival (DOA) of a target. The wavelength of the signal;

[0029] When the target angle is not zero, different transmitted signals arrive at the target at different times, resulting in different phases on the transmitting antenna; for MIMO radar, the different transmitted signals are orthogonal to each other. They represent the first and the The transmitted waveform is expressed as follows:

[0030] ;

[0031] In the formula, for conjugate, For the first The autocorrelation function of the transmitted waveform;

[0032] After pulse compression, the different transmitted waveforms are orthogonally separated at the receiving end; the Gaussian properties of the noise remain unchanged after pulse compression, so the pulse-compressed waveform... The expression for the signal received by each antenna is:

[0033] ;

[0034] In the formula, The first pulse pressure after The expression of the signal received by each antenna, For the first The echo amplitude of the target For the first The polarization steering vector matrix of each target. For the first The first goal One emission guidance vector element, For the first The first goal One receiving guide vector element, For the first The polarization scattering matrix of each target. For the first The electric field polarization vector of each transmitting element;

[0035] Depend on It is known that the same target generates echoes from M transmitting antennas. Each receiving antenna processes the M echoes through pulse compression to obtain a set of M receiving polarization vectors. These receiving polarization vectors all correspond to the same polarization scattering matrix. Define the following matrix and vector expressions:

[0036] ;

[0037] ;

[0038] ;

[0039] ;

[0040] ;

[0041] In the formula, For all The first objective is for the... The polarization-azimuth joint response matrix obtained after pulse compression processing of the echoes of the transmitted signals from each transmitting antenna has a size of 2×K. Let m be the diagonal matrix of the wave direction angle of the m-th transmitting antenna, and let the diagonal be the first... The element represents the first element. The first goal in the phase generated on the i th transmit antenna, with the value from 1 to M; is a direction of arrival angle matrix, the diagonal line of the matrix is an element represents the phase excited by the i th target on the j th receive antenna, an element represents the phase excited by the i th target on the j th receive antenna, with the value from 1 to N; is a snapshot sampling matrix of all targets, is the echo of the transmit signal of the i th target to the j th transmit antenna, and the polarization-azimuth joint response vector obtained after pulse compression processing has a size of 2x1; is a matrix transformation, which inputs a vector and transforms the vector into a diagonal matrix with the elements of the vector as the diagonal line elements; is an exponential with base e, is the transpose of a matrix, is a snapshot sampling value sequence of the i th target, is the i th snapshot sampling value of the i th target, and there are K snapshots, with the value from 1 to K; ; is the relationship between the polarization vector of the i th target and the elevation angle of the electromagnetic wave, is the polarization scattering matrix of the i th target, is a sampling vector of the i th target, with the value from 1 to M; is the number of sampling snapshots; is the i th transmit steering vector element of the i th target, and the subscript 1 is the first transmit steering vector element, and the subscript M is the M th transmit steering vector element; ; ; ; ; ; ; with the value from 1 to M; ; is the number of sampling snapshots; is the i th transmit steering vector element of the i th target, and the subscript 1 is the first transmit steering vector element, and the subscript M is the M th transmit steering vector element; ; ; ; ;

[0042] is written in the form of a matrix, and the expression is:

[0043] ;

[0044] ;

[0045] In the formula, is all the i th target to the j th transmit antenna, ​​The polarization-azimuth joint response matrix obtained after pulse compression processing of the echoes from the transmitted signals of each transmitting antenna is of size [value missing]. , The value ranges from 1 to M; Let m be the diagonal matrix of the wave direction angle of the m-th transmitting antenna, and let the diagonal be the first... The element represents the first element. The first goal in The phase generated on each transmitting antenna For the first The diagonal matrix of the direction of arrival angles of each receiving antenna;

[0046] The size is , to receive all the signal matrices Arranging them column-wise yields the complete receiver vector matrix. ;

[0047] make Indicates the first The emission polarization-DOD joint vector of each target. Indicates the first The DOA vector of each target; Expressed as follows:

[0048] ;

[0049] ;

[0050] ;

[0051] ;

[0052] In the formula, For Gaussian white noise, and All are set to powers of 2; For the first The polarization-azimuth joint response vector is obtained by pulse compression processing of the echo of the transmitted signal from the first transmitting antenna to the target. For the first The polarization-azimuth joint response vector is obtained by pulse compression processing of the echo of the transmitted signal from the Mth transmitting antenna to the target; the superscript T indicates transpose. For the first The first goal One receiving guide vector element, For the first The first goal One receiving guide vector element, For all The DOA matrix of each target. For all Emission polarization-DOD joint matrix of each target; For matrix The size is , All elements are complex elements; This is the emission polarization-DOD joint vector for the Kth target.

[0053] In step S2, using the reconstructed echo data, a third-order tensor is constructed. The third-order tensor is then decomposed using alternating least squares, including:

[0054] Will Every The column is folded to obtain a third-order tensor. ; The expression describing the optimization problem, obtained through PARAFAC decomposition, is as follows:

[0055] ;

[0056] ;

[0057] In the formula, To reconstruct the third-order tensor from the echo data, for The third-order unit tensor has diagonal elements that are all 1s and all other elements that are 0s. These are the product of mode-2 and mode-3, respectively. For tensor sum matrix The pattern -1 product, For tensor The result of expanding the pattern-2, To find the matrix The Frobenius norm; They are The estimated value is calculated using the alternating least squares method, and the expression is:

[0058] (1)

[0059] (2)

[0060] (3)

[0061] In the formula, and Each column corresponds to the polarization and angle information of the same target. for The estimated value, for The estimated value, for The estimated value, for transpose, for transpose, for transpose, This is the conjugate transpose. (1) is a tensor Mode-1 unfolds. (2) is a tensor Mode-2 expansion (3) is a tensor Mode-3 unfolds. , , For the first Columns correspond to the same first The true information of the polarization and angle of each target. and The Columns correspond to the same first The estimated values ​​of polarization and angle information of each target.

[0062] In step S3, the method for estimating the wave departure direction angle (DOD) includes:

[0063] use Represented as a matrix The Column, i.e., the first The launch polarization-DOD joint steering vector of each target; Two vectors and The form of the Hadama product:

[0064] ;

[0065] In the formula, for The estimated value, For the first One transmitting antenna; for transpose, For an extended launch steering vector, for The estimated value, for power of 0, for of Power;

[0066] Divide into 2 columns sub-vector, the first The subvectors are constructed as follows The expression is:

[0067] ;

[0068] In the formula, The selection matrix is ​​used to select certain rows and columns of data from the original matrix. Indicates size is A matrix whose elements are all 0. It is an M-order identity matrix. Indicates size is A matrix whose elements are all 0, 0 is a matrix whose elements are all zero, and I is the identity matrix;

[0069] A reconstructed emitter polarization-DOD joint estimation matrix is ​​obtained, namely:

[0070] ;

[0071] In the formula, For the reconstructed emitter polarization-DOD joint estimation matrix, The first column of E, It is a subscript indicating left; for The second column, It is a subscript, indicating right; for of The cases where the value is 1 or 2 respectively;

[0072] The following relationship must be satisfied:

[0073] ;

[0074] ;

[0075] In the formula, For matrix ,matrix ,matrix Multiply, for of Values The number, for of Power of 1 They are respectively The estimated value, For Kronecker product, is the Hadamard product;

[0076] Among the constituent elements of, only the middle part is different. The part with difference is extracted as matrix , respectively related to the reference transmit array element polarization state, polarization modulation mode and DOD, through estimating DOD; is the post- column of , is the pre- column of , , The relationship of is written as:

[0077] ;

[0078] ;

[0079] In the formula, is the matrix after reconstruction, the part with element difference between is a matrix with the size of 2x2, and the matrix elements are complex numbers; the pre- column of , the post- column of , is an invertible matrix, is the covariance matrix of , is the conjugate transpose;

[0080] There exists an invertible matrix satisfying:

[0081] ;

[0082] In the formula, is the signal subspace matrix of ;

[0083] Let represent the pre- column of , represent the post- column of , is the subscript, indicating signal; The relationship between is derived as follows:

[0084] ;

[0085] ;

[0086] where, is and the rotation invariance relation, is a similarity matrix;

[0087] From the property of similarity matrix, the eigenvalue of is equal to the eigenvalue of ; , and the eigenvalue of matrix satisfies:

[0088] ;

[0089] where, is the eigenvalue of is the conjugate transpose of

[0090] When the modulation mode of transmit polarization is determined, the matrix is no longer changed in the signal processing process, is a fixed value; and are both 2x2 invertible matrices, and there are two eigenvalue pairs corresponding to the same target, and the mean value method is taken to calculate the angle estimation value of the same target; by calculating and and are obtained.

[0091] ;

[0092] ;

[0093] where, is the eigenvalue of matrix , is the vector of , and the elements of every two elements are rearranged in order by column to form the matrix, is a set of matrices, and the elements of the matrix are complex elements;

[0094] for ​​Perform the above operation on each column to obtain a total of The estimated DOD of each target.

[0095] In step S3, the polarization scattering matrix estimation method includes:

[0096] Will Rearranged as :

[0097] ;

[0098] ;

[0099] ;

[0100] In the formula, For mathematical operations middle Take the value 7. This is another extended guide vector that has been constructed;

[0101] According to the properties of pseudo-inverse matrices, there exists a matrix... , , so that:

[0102] ;

[0103] Then the first The polarization scattering matrix of each target It is estimated to be:

[0104] ;

[0105] ;

[0106] In the formula, for pseudo-inverse matrix for The pseudo-inverse matrix, for A set of matrices, where all elements are complex numbers; It is a second-order identity matrix; for The result of multiplication is an intermediate variable; To convert a vector into a diagonal matrix, For the first The DOD estimation guidance vector for each target For all emission polarization modulation states, the first equation is estimated based on the above formula. The polarization scattering matrix of each target.

[0107] Furthermore, regarding each column of the target polarization scattering matrix. each column of the target polarization scattering matrix.

[0108] Another object of the present application is to provide a polarization MIMO multi-parameter estimation system based on transmit polarization modulation, which implements the polarization MIMO multi-parameter estimation method based on transmit polarization modulation.

[0109] The polarization MIMO high-frequency ground wave radar array structure is composed of a transmitting end and a receiving end; the transmitting end performs transmit polarization modulation on the target signal transmitted by the transmitting array element through a polarization phase controller, and the receiving end receives the echo data of the target after transmit polarization modulation, performs pulse compression processing on the echo data, and then performs echo data reconstruction.

[0110] The tensor decomposition module is used to construct a third-order tensor form by using the reconstructed echo data, and perform tensor decomposition on the third-order tensor form by using an alternating least squares method.

[0111] The multi-parameter joint estimation signal processing module performs polarization parameter joint estimation by using a multi-parameter joint estimation signal processing method based on the result of tensor decomposition, and outputs the polarization parameter estimation result; the multi-parameter joint estimation signal processing method includes wave departure direction angle (DOD) estimation, wave arrival direction angle (DOA) estimation, and polarization scattering matrix estimation.

[0112] Further, the system is mounted on a computer readable storage medium, and the computer readable storage medium stores a computer program; when the computer program is executed by a processor, the function of the above-mentioned method can be realized.

[0113] In combination with all the above technical solutions, the present application has the following beneficial effects:

[0114] Firstly, according to the existing HFSWR working principle, the present application designs a new type of high-frequency ground wave radar transmitting and receiving array structure and a corresponding P-MIMO-HFSWR signal processing method, and realizes multi-parameter high-precision estimation of a sea surface target.

[0115] Secondly, the application innovatively proposes a transmitting polarization tilt angle modulation method of a transmitting end, a reconstruction method of echo data into a third-order tensor to ensure automatic pairing between parameters, and a joint estimation of multiple parameters at the same time according to the special structure of the transmitting polarization-DOD joint steering vector. The application provides an implementation mode for a polarization diversity MIMO radar and designs a signal processing method therefor. Compared with a single modulation mode of the transmitting polarization of a traditional algorithm, all transmitting polarizations are set to the same polarization tilt angle and polarization phase difference. BRIEF DESCRIPTION OF DRAWINGS

[0116] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the description, further serve to explain the principles of the present disclosure;

[0117] Figure 1 is a polarization MIMO multi-parameter estimation method flowchart based on transmitting polarization modulation provided by the application embodiment;

[0118] Figure 2 is an array arrangement mode schematic diagram provided by the application embodiment;

[0119] Figure 3 is a transmitting end system structure diagram provided by the application embodiment;

[0120] Figure 4 is a receiving end system structure diagram provided by the application embodiment;

[0121] Figure 5 is an echo data reconstruction schematic diagram provided by the application embodiment;

[0122] Figure 6 is a target 1 angle estimation distribution diagram provided by the application embodiment;

[0123] Figure 7 is a target 2 angle estimation distribution diagram provided by the application embodiment;

[0124] Figure 8 is a DOA RMSE estimation result simulation diagram changing with signal-to-noise ratio provided by the application embodiment;

[0125] Figure 9 is a DOD RMSE estimation result simulation diagram changing with signal-to-noise ratio provided by the application embodiment;

[0126] Figure 10 is a receiving polarization phase difference RMSE estimation result simulation diagram changing with signal-to-noise ratio provided by the application embodiment;

[0127] Figure 11 is a receiving polarization phase difference RMSE estimation result simulation diagram changing with signal-to-noise ratio provided by the application embodiment. DETAILED DESCRIPTION

[0128] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the drawings. In the following description, a large number of specific details are set forth in order to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the concept of the present application, so the present application is not limited to the specific implementation disclosed below.

[0129] The innovation of the present application is that: the present application designs a special mimo polarization sensitive array and designs a transmission polarization modulation method, on this basis, a multi-parameter joint estimation method is proposed, which realizes the multi-parameter joint estimation of the transmission angle, receiving angle and polarization scattering matrix of the radar.

[0130] Embodiment 1, as shown in the figure, the polarization MIMO multi-parameter estimation method based on transmission polarization modulation provided by the embodiment of the present application comprises the following steps: Figure 1

[0131] S1, design a polarization multiple-input multiple-output high-frequency ground wave radar array structure composed of a transmitting end and a receiving end; wherein the transmitting end modulates the transmission polarization of the target signal transmitted by the transmitting element through a polarization phase controller, and the receiving end receives the echo data of the target after the transmission polarization modulation, and reconstructs the echo data after pulse compression processing;

[0132] S2, using the reconstructed echo data, constructing a three-order tensor form, and decomposing the three-order tensor form through an alternating least squares method;

[0133] S3, based on the result of tensor decomposition, using a multi-parameter joint estimation signal processing method to perform polarization parameter joint estimation, and outputting the polarization parameter estimation result; the multi-parameter joint estimation signal processing method comprises: wave departure direction angle DOD estimation, wave arrival direction angle DOA estimation and polarization scattering matrix estimation.

[0134] In step S1, the present application designs a polarization multiple-input multiple-output high-frequency ground wave radar array structure as shown in the array arrangement mode diagram, which is composed of a transmitting end and a receiving end. Figure 2

[0135] (1) Transmitting end design method.

[0136] The transmitting end is composed of M transmitting elements forming a uniform linear array, each transmitting element is composed of a group of orthogonal electric dipoles, which are distributed parallel to the Y axis and the Z axis respectively, and the transmission polarization state of the transmitting element is modulated through a polarization phase controller of the transmitting element. ​​

[0137] In the present application, the modulation method of the transmitting polarization is as follows: the transmitting end adopts linear polarization mode, and the transmitting array element at the coordinate origin in Figure 2 is the reference array element, and the transmitting polarization inclination angle of other transmitting array elements relative to the reference array element has a fixed difference . The transmitting end has M transmitting array elements. Other transmitting array elements refer to the other M-1 array elements except the reference array element. According to the schematic diagram in Figure 2 , the reference array element is the array element marked with 1, the transmitting polarization inclination angle difference between the second array element and the reference array element is , and the transmitting polarization inclination angle difference between the mth (m is an integer sequence number, representing any number from 1 to M) array element and the reference array element is . For a general EMVA, the electromagnetic response of a single transmitting array element satisfies the following formula:

[0138] ;

[0139] In the formula, E is the electromagnetic response of a single transmitting array element, is the imaginary unit, is the pitch angle, is the azimuth angle, matrix is the relationship between the polarization vector and the pitch angle of the electromagnetic wave, vector is the electric field polarization vector, is the polarization inclination angle, and is the polarization phase difference. According to the polarization knowledge, the polarization scattering matrix of the target, the transmitting electric field polarization vector, and the receiving electric field polarization vector are expressed as:

[0140]

[0141] ;

[0142] Take as an example: subscript H represents the horizontal component, superscript R represents receiving, subscript V represents the transmitting component, and superscript T represents receiving. represents the signal echo intensity of the reflected horizontal component when the target receives the horizontal component signal. represents the signal echo intensity of the reflected vertical component when the target receives the horizontal component signal. represents the signal echo intensity of the reflected horizontal component when the target receives the vertical component signal. represents the signal echo intensity of the reflected vertical component when the target receives the vertical component signal. is the transmitting electric field polarization vector, and the expression is the same as that of . is the receiving electric field polarization vector, and has the same expression as .​ targeted polarization scattering matrix, the vertical polarization scattering coefficient generated by the target when the horizontal polarization is incident, and the rest The meaning of the matrix elements is similar. Define the selection matrix where, and respectively represent the all-zero matrix and the unit matrix. For the array structure in the present application, the single-element electromagnetic response can be represented as:

[0143] ;

[0144] In the formula, is the selected element after the selection matrix acts.

[0145] Since the transmitting end adopts linear polarization mode and the signal only propagates along the YOZ plane, then is fixed at 90°, abbreviated as , .

[0146] The electric field polarization vector of the reference element of the transmitting end is represented as:

[0147] ;

[0148] In the formula, is the electric field polarization vector of the reference element of the transmitting end, is the imaginary unit, is the transpose of the vector, is the polarization tilt angle of the reference element of the transmitting end, is the polarization phase difference of the reference element of the transmitting end, is a constant ;

[0149] The electric field polarization vector of the first transmitting element can be modulated as:

[0150] ;

[0151] In the formula, is the electric field polarization vector of the first transmitting element, is an integer serial number, representing any one number from 1 to M;

[0152] For matrix transformation, there are the following properties:

[0153] ;

[0154] The The consecutive multiplication of three identical matrices is defined as... ,Right now: Then we have: Establish the polarization modulation mode of the remaining array elements relative to the reference array element.

[0155] The transmitter has M transmitting elements, and the remaining elements refer to the M-1 elements other than the reference element. The remaining elements represent the electric field polarization vector of the (M-1)th transmitting element. When calculating the electric field polarization vector of the (M-1)th transmitting element, it is substituted into the formula for matrix operations. This establishes the polarization modulation method of the remaining elements relative to the reference element. Since the polarization of the electromagnetic wave is independent of the frequency and phase of the transmitted signal, the orthogonality of the waveform can be designed independently when implementing orthogonal modulation of the transmitted signal, and any existing HFSWR orthogonal waveform can be applied to this transmitter. Therefore, the... The signal transmitted by each transmitting antenna can be represented as:

[0156] ;

[0157] It is understandable that the innovation of this invention is proposed in the first... The electric field polarization vector expression for each transmitting element This effectively expands the polarization diversity in MIMO radar.

[0158] (2) Echo model of the receiver.

[0159] The receiver consists of a uniform linear array of N elements. Each element comprises a set of orthogonal electric dipoles, distributed parallel to the Y and Z axes, respectively, to receive fully polarized echoes parallel to the XOY plane. Assuming there are K independent targets in the far field, then the... The expression for the signal received by each antenna is:

[0160] ;

[0161] In the formula, For the first The signal received by each antenna The number of independent targets in the scene. The number of transmitting antennas. For the first The polarization steering vector matrix of each target. For the first The receiver polarization vector of a target, For the first The transmitted signal of each array element For the first The first goal One emission guidance vector element, For the first The first goal One receiving guide vector element, The received Gaussian white noise sequence, The index to be received. The subscript for launch;

[0162] They are defined as follows:

[0163] ;

[0164] ;

[0165] In the formula, For the first The first goal in The phase generated on each transmitting antenna For the first The first goal in The phase excited on each receiving antenna, These are the element spacings at the transmitting and receiving ends, respectively. The first The direction of departure (DOD) and direction of arrival (DOA) of a target. The wavelength of the signal;

[0166] For MIMO radar, different transmitted signals are orthogonal to each other. They represent the first and the The transmitted waveform is expressed as follows:

[0167] ;

[0168] In the formula, for conjugate, For the first The autocorrelation function of the transmitted waveform;

[0169] After pulse compression, different transmitted waveforms can be orthogonally separated at the receiving end. Assuming the Gaussian properties of the noise remain unchanged after pulse compression, the pulse-compressed... The expression for the signal received by one antenna can be further written as a formula:

[0170] ;

[0171] In the formula, The first pulse pressure after The expression of the signal received by each antenna, For the first The echo amplitude of each target, For the first The polarization steering vector matrix of each target. For the first The first goal One emission guidance vector element, For the first The first goal One receiving guide vector element, For the first The polarization scattering matrix of each target. For the first The electric field polarization vector of each transmitting element;

[0172] Depend on It is known that the same target generates echoes from M transmitting antennas. Each receiving antenna processes the M echoes through pulse compression to obtain a set of M receiving polarization vectors. These receiving polarization vectors all correspond to the same polarization scattering matrix. Define the following matrix and vector expressions:

[0173] ;

[0174] ;

[0175] ;

[0176] ;

[0177] ;

[0178] In the formula, For all The first objective is for the... The polarization-azimuth joint response matrix obtained after pulse compression processing of the echoes of the transmitted signals from each transmitting antenna has a size of 2×K. Let m be the diagonal matrix of the wave direction angle of the m-th transmitting antenna, and let the diagonal be the first... The element represents the first element. The first goal in The phase generated on each transmitting antenna The value ranges from 1 to M; This is a diagonal matrix of directions of arrival, with the diagonal lines... The element represents the first element. The first goal in The phase excited on each receiving antenna, The value ranges from 1 to N; The snapshot sampling matrix for all targets. For the first The first objective is for the... The polarization-azimuth joint response vector obtained after pulse compression processing of the echo of the transmitted signal from each transmitting antenna has a size of 2×1. For matrix transformation, take a vector as input and transform it into a diagonal matrix whose elements are on the diagonal. The exponent is a constant e. This is the transpose of the matrix. For the first The sequence of all snapshot samples of each target For the first The first goal There are 10 snapshot sample values, totaling 10 ... Each snapshot has a value ranging from 1 to... ; For the first The relationship between the polarization vector of a target and the elevation angle of the electromagnetic wave. For the first The polarization scattering matrix of each target. For the first The sampling vector of each target, The value ranges from 1 to ; This represents the number of snapshots taken. For the first The first goal There are several emission steering vector elements, with index 1 being the first emission steering vector element. That is the first One emission guidance vector element;

[0179] Written in matrix form, the expression is:

[0180] ;

[0181] ;

[0182] In the formula, For all The first objective is for the... The polarization-azimuth joint response matrix obtained after pulse compression processing of the echoes from the transmitted signals of each transmitting antenna is of size [value missing]. , The value ranges from 1 to M; Let m be the diagonal matrix of the wave direction angle of the m-th transmitting antenna, and let the diagonal be the first... The element represents the first element. The first goal in The phase generated on each transmitting antenna For the first The diagonal matrix of the direction of arrival angles of each receiving antenna;

[0183] The size is , to receive all the signal matrices Arranging them column-wise yields the complete receiver vector matrix. ;

[0184] make Indicates the first The emission polarization-DOD joint vector of each target. Indicates the first The DOA vector of each target; Expressed as follows:

[0185] ;

[0186] ;

[0187] ;

[0188] ;

[0189] In the formula, For Gaussian white noise, and All are set to powers of 2; For the first The polarization-azimuth joint response vector is obtained by pulse compression processing of the echo of the transmitted signal from the first transmitting antenna to the target. For the first The polarization-azimuth joint response vector is obtained by pulse compression processing of the echo of the transmitted signal from the Mth transmitting antenna to the target; the superscript T indicates transpose. For the first The first goal One receiving guide vector element, For the first The first goal One receiving guide vector element, For all The DOA matrix of each target. For all Emission polarization-DOD joint matrix of each target; For matrix The size is , All elements are complex elements; This is the emission polarization-DOD joint vector for the Kth target.

[0190] It can be understood that according to the principle of MIMO signal processing, the transmitting polarization modulation mode proposed in the application improves the traditional echo model. In addition to the pulse compression principle, the application innovatively proposes the above formula to pre-process the echo signal to form a three-order tensor.

[0191] For example, in step S2, the echo data reconstructed in step S1 is constructed into a three-order tensor form, and then the three-order tensor form is decomposed by the alternating least squares method, including:

[0192] As shown in Figure 2 , each column is folded to obtain a three-order tensor . ; Through PARAFAC decomposition, the expression described as an optimization problem is as follows:

[0193] ;

[0194] ;

[0195] In the formula, is the three-order tensor after reconstruction of the echo data, is the three-order unit tensor of , the elements on the diagonal are all 1, and the remaining elements are all 0; are mode-2 products and mode-3 products, respectively; is the mode-1 product of the tensor and the matrix , is the mode-2 expansion result of the tensor , is the Frobenius norm of the matrix ; are estimated values of , respectively, which can be calculated by the alternating least squares method proposed in the application, and the expression is as follows:

[0196] (1);

[0197] (2);

[0198] (3);

[0199] In the formula, and each column corresponds to the polarization and angle information of the same target, is the estimated value of , is an estimate of is an estimate of is the transpose of is the transpose of is the transpose of is the conjugate transpose of is the mode-1 unfolding of tensor is the mode-2 unfolding of tensor is the mode-3 unfolding of tensor is the i-th column of corresponds to the real information of polarization and angle of the i-th target, corresponds to the estimate of polarization and angle information of the i-th target. Exemplarily, in step S3, the direction of arrival angle DOA estimation method comprises:

[0200]

[0201] the i-th column of is denoted as the first and last columns of are denoted as and satisfy the following shift-invariance:

[0202]

[0203] construct an extended steering vector matrix , and the i-th DOA can be obtained by the following method:

[0204]

[0205]

[0206] wherein is an eigenvalue of a matrix, is a phase of the element.

[0207] ​​​​​​​​​​​​​​​​​​​​​​​Each column is processed using the algorithm described above, resulting in DOA information for a total of K targets.

[0208] No. The matrix relating the polarization vector excited by a target to the elevation angle of the electromagnetic wave. It can be written as:

[0209] ;

[0210] Exemplary methods for estimating the wave-departure direction angle (DOD) include:

[0211] use Represented as a matrix The Column, i.e., the first The launch polarization-DOD joint steering vector of each target; Two vectors and The form of the Hadama product:

[0212] ;

[0213] In the formula, for The estimated value, For the first One transmitting antenna; for transpose, For an extended launch steering vector, for The estimated value, for power of 0, for of Power;

[0214] Divide into 2 columns sub-vector, the first The subvectors are constructed as follows The expression is:

[0215] ;

[0216] In the formula, The selection matrix is ​​used to select certain rows and columns of data from the original matrix. Indicates size is A matrix whose elements are all 0. It is an M-order identity matrix. Indicates size is A matrix whose elements are all 0, 0 is a matrix whose elements are all zero, and I is the identity matrix;

[0217] This invention innovatively proposes to obtain a reconstructed emitter polarization-DOD joint estimation matrix, namely:

[0218] ;

[0219] In the formula, For the reconstructed emitter polarization-DOD joint estimation matrix, The first column of E, It is a subscript indicating left; for The second column, It is a subscript, indicating right; for of The cases where the value is 1 or 2 respectively;

[0220] The following relationship must be satisfied:

[0221] ;

[0222] ;

[0223] In the formula, For matrix ,matrix ,matrix Multiply, for of Values The number, for of Power of 1 They are respectively The estimated value, For Kronecker product, For Hadamah accumulation;

[0224] According to the above formula, The constituent elements differ only in the middle part; the differing part is extracted into a matrix. , These are related to the polarization state of the reference transmitter element, the polarization modulation method, and the DOD, respectively. The first two are known and controllable, therefore they can be determined through... Estimate DOD; yes After List, yes The former List, , and The relation is written as:

[0225] ;

[0226] ;

[0227] In the formula, To make the matrix After reconstruction, A matrix formed by the differences between the elements; The matrix is ​​of size 2×2, and all its elements are complex numbers; The former Listed as , After Listed as , It is an invertible matrix. for The covariance matrix, It is the conjugate transpose;

[0228] There exists an invertible matrix satisfy:

[0229] ;

[0230] In the formula, for The signal subspace matrix;

[0231] Similarly, using express The former List, express After List, The subscript indicates signal; and The relationship between them is derived as follows:

[0232] ;

[0233] ;

[0234] In the formula, for and The rotation-invariant relation, It is a similarity matrix;

[0235] From the properties of similar matrices, we know that eigenvalues and eigenvalues equal; , with the eigenvalue of the matrix satisfies:

[0236] ;

[0237] wherein, is the eigenvalue of the matrix , is the conjugate transpose of the matrix ;

[0238] When the modulation mode of the polarized emission is determined, the matrix is no longer changed in the signal processing process, is a determined value; and are both 2x2 reversible matrices, and two eigenvalue pairs correspond to the same target, and the average method is adopted to calculate the angle estimation value of the same target; the application innovatively proposes that and are obtained and .

[0239] ;

[0240] ;

[0241] wherein, is the eigenvalue of the matrix , is the vector of , and the order of every two elements is rearranged in the column to form the matrix , and is a set of matrices, and the elements of the matrix are complex elements;

[0242] The above operation is performed on each column of , and the DOD estimation value of a total of targets is obtained.

[0243] Exemplarily, the polarization scattering matrix estimation method includes: the polarization scattering matrix estimation method must be performed under the premise that the wave departure direction angle DOD and the wave arrival direction angle DOA have been estimated. Similar to the operation in the wave departure direction angle DOD estimation method, the matrix is rearranged as :

[0244] ;

[0245] ;

[0246] ;

[0247] In the formula, For mathematical operations middle Take the value 7. This is another extended guide vector that has been constructed;

[0248] According to the properties of pseudo-inverse matrices, there exists a matrix... , , so that:

[0249] ;

[0250] Then the first The polarization scattering matrix of each target It is estimated to be:

[0251] ;

[0252] ;

[0253] In the formula, for pseudo-inverse matrix for The pseudo-inverse matrix, for A set of matrices, where all elements are complex numbers; It is a second-order identity matrix; for The result of multiplication is an intermediate variable; To convert a vector into a diagonal matrix, For the first The DOD estimation guidance vector for each target For all emission polarization modulation states, the first equation is estimated based on the above formula. The polarization scattering matrix of each target.

[0254] It is understandable that the above-mentioned methods for constructing third-order tensors and for PARAFAC tensor decomposition are adapted from classical methods based on the signal model proposed in this invention. The direction of arrival (DOA) estimation method is a traditional method, while the direction of departure (DOD) and polarization scattering matrix estimation methods are innovatively proposed in this invention, achieving the effects of joint parameter estimation and automatic pairing.

[0255] Example 2, the polarization MIMO multi-parameter estimation system based on transmit polarization modulation provided in this embodiment of the invention includes:

[0256] The polarized multiple-input multiple-output high-frequency ground wave radar array structure is composed of a transmitting end and a receiving end; the transmitting end performs transmitting polarization modulation on a target signal transmitted by a transmitting array element through a polarization phase controller; the receiving end receives echo data of the target after transmitting polarization modulation, and performs echo data reconstruction after pulse compression processing on the echo data;

[0257] A tensor decomposition module is configured to construct a three-order tensor form using the reconstructed echo data, and perform tensor decomposition on the three-order tensor form through an alternating least square method.

[0258] A multi-parameter joint estimation signal processing module is configured to perform polarized parameter joint estimation using a multi-parameter joint estimation signal processing method based on the result of the tensor decomposition, and output a polarized parameter estimation result; the multi-parameter joint estimation signal processing method includes wave departure direction angle (DOD) estimation, wave arrival direction angle (DOA) estimation and polarized scattering matrix estimation.

[0259] The array structure of the application is arranged in the form of Figure 2 The transmitting end is provided with array elements, and the receiving end is provided with array elements, each of which is composed of two polarization-sensitive electric dipoles. Figure 2 The array element number shown in the figure is defined as the positive direction of the coordinate axis Y, the vertical upward direction is the positive direction of the Z axis, and the X axis satisfies the Cartesian coordinate system. The two electric dipoles of each array element are arranged in parallel to the Y axis and the Z axis on the Y axis. In the coordinate system, the signal is injected from the XOY plane, and the target distribution is in the X negative half-axis region of the XOY plane.

[0260] The transmitting end structure of the application is shown in Figure 3 The system control module is composed of a high-performance computer, which is linked with a signal generator and a polarization phase controller through an Ethernet. The signal generator generates M orthogonal signals for different transmitting array elements, and the two dipoles of the same array element transmit the same signal. The polarization phase controller modulates the phase of each transmitting array element according to the transmitting polarization modulation method proposed by the application. The signal generator and the polarization phase controller are connected with the array elements through cables to realize the control of transmission.

[0261] The receiving end structure of the application is shown in Figure 4The receiving array is connected to the analog front end through a cable. The analog front end filters the echo signal, and after low noise amplification, the signal is input to the A / D acquisition module through the cable. The A / D acquisition module acquires the analog signal as a digital signal by setting a suitable sampling rate, and then performs digital down conversion to transform the carrier signal into a baseband signal, and then inputs it into the signal processing module through Ethernet. The signal processing module is a high-performance computer, which first performs pulse compression processing on the baseband signal, and then performs multi-parameter joint estimation according to the signal processing method proposed in the application.

[0262] Figure 5 A schematic diagram of constructing the data after pulse compression into a third-order tensor is shown. The original data is constructed into a 2-dimensional matrix, and the first The data of the first The data of the first Figure 4 The data of the first

[0263] Figures 6 to 11 A simulation schematic diagram provided by the application is shown. The simulation parameters are shown in Table 1.

[0264] Table 1 Simulation parameter setting table

[0265]

[0266] Figure 6 and Figure 7 The estimated angle distribution and the preset angle distribution of the two targets when the Monte Carlo simulation is 200 times are shown. It can be seen that the estimated angle is compactly distributed around the preset angle.

[0267] Figure 8 The RMSE of DOA estimation result simulation diagram with signal-to-noise ratio change is shown. The signal-to-noise ratio changes from-3dB to 15dB, and the interval is 3dB. The RMSE calculation formula of parameter y is:

[0268] ;

[0269] In the formula, is the number of parameters, is the estimation result, is the preset parameter.

[0270] Parameter The smaller the RMSE of the DOD is, the better the estimation performance of the method is. The proposed method has better performance than the traditional methods of ESPRIT and MIMO-ESPRIT.

[0271] Figure 9 The simulation diagram of the estimation result of the RMSE of the DOD with the change of the signal-to-noise ratio is shown in the figure, the signal-to-noise ratio changes from-3dB to 15dB, and the interval is 3dB, and the proposed method has better performance than the traditional method of MIMO-ESPRIT.

[0272] The polarization scattering matrix contains four variables, and it is difficult to directly reflect the estimation result. The estimation performance of the polarization scattering matrix is measured by the estimation performance of the polarization tilt angle and the polarization phase difference of the polarization corresponding to the first transmitting antenna. Figures 10 to 11 The simulation diagram of the estimation result of the RMSE of the polarization tilt angle and the polarization phase difference with the change of the signal-to-noise ratio is shown in the figure, and the proposed method has better performance than the traditional method of MIMO-ESPRIT.

[0273] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any modification, equivalent replacement and improvement made by any person skilled in the art within the technical range disclosed by the present application, as long as it is within the spirit and principle of the present application, should be covered within the protection scope of the present application.

Claims

1. A polarization MIMO multi-parameter estimation method based on transmit polarization modulation, characterized in that, The method comprises the following steps: S1, designing a polarized multiple-input multiple-output high-frequency ground wave radar array structure composed of a transmitting end and a receiving end; wherein the transmitting end modulates the target signal transmitted by the transmitting elements through a polarization phase controller, and the receiving end receives the echo data of the target after the transmitting polarization modulation, performs pulse compression processing on the echo data, and then reconstructs the echo data; S2, using the reconstructed echo data to construct a three-order tensor form, and performing tensor decomposition on the three-order tensor form through an alternating least squares method; S3, based on the result of the tensor decomposition, using a multi-parameter joint estimation signal processing method to perform polarized parameter joint estimation, and outputting the polarized parameter estimation result; the multi-parameter joint estimation signal processing method comprises: wave departure direction angle DOD estimation, wave arrival direction angle DOA estimation, and polarized scattering matrix estimation.

2. The polarization MIMO multi-parameter estimation method based on transmit polarization modulation according to claim 1, characterized in that, In step S1, the transmitting end is composed of M transmitting elements arranged in a uniform linear array, and each transmitting element is composed of a group of orthogonal electric dipoles arranged parallel to the Y-axis and the Z-axis. The polarization phase controller of the transmitting element is used to modulate the transmitting polarization state of the transmitting element. The method for modulating the transmitting polarization state of the transmitting element comprises: the transmitting end adopts a linear polarization mode, the transmitting element at the coordinate origin is a reference element, and the transmitting polarization inclination angle of the other transmitting elements relative to the reference element has a fixed difference Δ. The electric field polarization vector of the reference element of the transmitting end is represented as: In the formula, ζ t1 is the electric field polarization vector of the reference element of the transmitting end, j is the imaginary unit, T is the transpose of the vector, a1 is the polarization tilt angle of the reference element of the transmitting end, b1 is the polarization phase difference of the reference element of the transmitting end, and e is the constant e. The electric field polarization vector of the mth transmitting element is modulated as: In the formula, ζ tm is the electric field polarization vector of the mth transmitting element, m is an integer serial number, representing any one of 1 to M; For matrix transformation, there is: In the formula, T is a Givens rotation matrix; The successive multiplication of n identical matrices is defined as (T) n i.e. Then we have: ζ tm = (T) m-1 ζ t1 ; the polarization modulation mode of the remaining elements relative to the reference element is established.

3. The transmit polarization modulation based polarization MIMO multi-parameter estimation method according to claim 1, characterized in that, In step S1, after pulse compression processing is performed on the echo data, the echo data is reconstructed, which comprises: In the far field, there are K independent targets, and the signal expression received by the nth antenna is: wherein X n is the signal received by the nth antenna, K is the number of independent targets in the scene, M is the number of transmitting antennas, Q k is the polarization steering vector matrix of the kth target, η rm，k is the receiving polarization vector of the kth target, s m (t) is the transmitting signal of the mth array element, exp(jδ tm,k ) is the mth transmitting steering vector element of the kth target, exp(jδ rn,k ) is the nth receiving steering vector element of the kth target, n is the received Gaussian white noise sequence, r is the receiving subscript, and t is the transmitting subscript. δ tm，k , δ rn，k are defined as: where δ tm，k is the phase generated by the kth target on the mth transmit antenna, δ rn，k is the phase excited by the kth target on the nth receive antenna, d r ,d t are the element spacing of the transmit and receive arrays, respectively, θ k , are the direction of departure (DOD) and direction of arrival (DOA) of the kth target, respectively, and λ is the wavelength of the signal. When the angle of the target is not 0, the time of different transmitting signals reaching the target is different, thus the phase generated on the transmitting antenna is different; for the MIMO radar, the different transmitting signals are orthogonal to each other, and the phase of the transmitting signal is expressed as s m1 (t),s m2 (t) respectively represent the m1th and m2th transmitting waveforms, and the expression is: wherein s m2 the conjugate of t, p m1 t is the autocorrelation function of the m1th transmit waveform; After pulse compression, the different transmitting waveforms are orthogonally separated at the receiving end. The high-strength noise remains unchanged after pulse compression, and the signal expression received by the nth antenna after pulse compression is: where X n is the signal expression received by the nth antenna after pulse compression, p k is the echo amplitude of the kth target, Q k is the polarization steering vector matrix of the kth target, exp(jδ tM,k ) is the mth element of the Mth transmit steering vector of the kth target, exp(jδ rn，k ) is the nth element of the receive steering vector of the kth target, S k is the polarization scattering matrix of the kth target, ζ tm is the electric field polarization vector of the mth transmit element; By η rm,k = S k ζ tm Knowing that the same target produces M echoes of the transmitting antennas, each receiving antenna will get a set of M received polarization vectors after pulse compression, and this set of received polarization vectors corresponds to the same polarization scattering matrix; define the following matrix and vector expressions: c m = [c m1 ,..., c mk ], c mk = Q k S k ζ tm where c m is the polarization-azimuth joint response matrix of the echo of the transmit signal of the mth transmit antenna after pulse compression, with the size of 2×K; is the wave departure direction angle diagonal matrix of the mth transmit antenna, and the kth element on the diagonal line represents the phase generated by the kth target on the mth transmit antenna, where m is an integer from 1 to M; is the wave direction angle diagonal matrix, and the kth element on the diagonal line represents the phase excited by the kth target on the nth receive antenna, where n is an integer from 1 to N; ρ mk is the polarization-azimuth joint response vector of the echo of the transmit signal of the mth transmit antenna after pulse compression, with the size of 2×1; diag() is a matrix transformation, which transforms an input vector into a diagonal matrix with the elements of the vector as the elements on the diagonal line; exp() is the exponential with the base of e; T is the transpose of a matrix, is the sequence of all snapshot sampling values of the kth target, ρ kL is the Lth snapshot sampling value of the kth target, and there are L snapshots, with the value ranging from 1 to L; Q k is the relationship between the polarization vector of the kth target and the elevation angle of the electromagnetic wave, S k is the polarization scattering matrix of the kth target, is the sampling vector of the kth target, with k ranging from 1 to K; L is the number of snapshot samples; exp(jδ tm，K ) is the mth transmit steering vector element of the kth target, where the subscript 1 is the first transmit steering vector element, and the subscript m is the mth transmit steering vector element. X n In matrix form, the expression is written as: wherein c M is the polarized-azimuth joint response matrix of all K targets to the echo of the transmit signal of the mth transmit antenna, with size 2 x K, and m is valued from 1 to M; is the boresight direction angle diagonal matrix of the mth transmit antenna, and the kth element on the diagonal represents the phase generated by the kth target on the mth transmit antenna, is the boresight direction angle diagonal matrix of the n th receive antenna; X n of size 2M x L, the complete received signal matrix X n , n = 1, 2,... N, is obtained by arranging all the received signal matrices X Let denote the transmit polarization-DOD joint vector of the kth target, denote the DOA vector of the kth target; is expressed by the following equation: where N w M and N are both set as power of 2, and Gaussian white noise is added; is the echo of the transmission signal of the first transmitting antenna of the kth target, and the polarization-azimuth joint response vector obtained after pulse compression processing; is the echo of the transmission signal of the Mth transmitting antenna of the kth target, and the polarization-azimuth joint response vector obtained after pulse compression processing; the superscript T represents transposition; is the nth receiving steering vector element of the kth target, is the nth receiving steering vector element of the kth target, P is the DOA matrix of all K targets, and O is the transmission polarization-DOD joint matrix of all K targets; is the size of matrix A is N×K, and the elements of A are complex elements; o K is the transmission polarization-DOD joint vector of the Kth target.

4. The polarization MIMO multi-parameter estimation method based on transmit polarization modulation according to claim 3, characterized in that, In step S2, the reconstructed echo data is used to construct a three-order tensor form, and tensor decomposition is performed on the three-order tensor form through an alternating least squares method, which comprises: Will Folding every 2M columns yields a third-order tensor. O, P, and ρ are obtained through PARAFAC decomposition, and the expression describing the optimization problem is: where Y is the third-order tensor after reconstructing the echo data, I 3，K is a third-order identity tensor with K x K x K, the diagonal elements are 1 and the rest are 0; x2, x3 are mode-2 product and mode-3 product respectively; Y x1B is the mode-1 product of tensor Y and matrix B, [Y] (2) is the mode-2 unfolding result of tensor Y, ||A|| F is the Frobenius norm of matrix A; are the estimated values of O, P, p respectively, which are calculated by the alternating least squares method, and the expression is: wherein, and each column of is an estimate of is an estimate of is an estimate of is the transpose of is the transpose of is the transpose of is the transpose of is the conjugate transpose of is the conjugate transpose of is the conjugate transpose of (1) is the mode-1 unfolding of tensor Y, (2) is the mode-2 unfolding of tensor Y, (3) is the mode-3 unfolding of tensor Y, is the k-th column of and is the k-th column of 5. The transmit polarization modulation based polarization MIMO multi-parameter estimation method according to claim 1, characterized in that, In step S3, the method for estimating the wave departure direction angle DOD comprises: with the k-th column of the matrix , i.e. the transmit polarization-DOD joint steering vector for the k-th target; is in the form of the Hadamard product of the two vectors and . wherein is an estimate of c mk , m is the mth transmit antenna; is the transpose of , z a is an extended transmit steering vector, is an estimate of θ k , m is the mth transmit antenna; is the 0th power of , m is the mth transmit antenna; is the M-1st power of z k , m is the mth transmit antenna; The column is divided into two Mx1 sub-vectors, and the qth sub-vector is configured as The expression is: where J q is a selection matrix used to select data from certain rows and columns of the original matrix; 0 M×(q-1)M denotes an M x (q-1)M matrix of zeros, I M×M is an M x M identity matrix, 0 M×(2-q)M denotes an M x (2-q)M matrix of zeros, 0 is a matrix of zeros, I is an identity matrix; A reconstructed transmitting polarization-DOD joint estimation matrix is obtained, that is: In the formula, E is the reconstructed emitter polarization-DOD joint estimation matrix, E l is the first column of E, and l is a subscript, indicating left; r E is the second column of E, and r is a subscript, indicating right; J1 and J2 are q values of J q respectively taking 1 or 2. E l , E r satisfies the following relation: where is a matrix is a matrix is a matrix (T) M / 2-1 is multiplied by is is a number with m taking values from M / 2, is is M / 2-1 power of are Q k are estimates of k are estimates of is a Kronecker product, is a Hadamard product; E l , E r Among the constituent elements of E, only the middle part is different, and the part with differences is extracted as a matrix E com respectively with the reference transmit array element polarization state, polarization modulation mode and DOD, and the DOD is estimated through E com ; E down is the last 2(M-1) columns of E, E up is the first 2(M-1) columns of E, E down , E up and E com The relationship of E com is written as: where E com After the matrix E is reconstructed, E l , E r is a matrix composed of the difference between the elements of E is a 2x2 matrix, and the elements of the matrix are complex numbers; the first 2(M-1) columns of E up are E down , and the last 2(M-1) columns of E E are E H is the covariance matrix of E H is the conjugate transpose There is an invertible matrix ∑ that satisfies: U s = E∑ wherein U S is a signal subspace matrix of R E ; U Sup represents the first 2(M-1) columns of U S represents the last 2(M-1) columns of U Sdown represents the first 2(M-1) columns of U S represents the last 2(M-1) columns of U sup and U Sdown is derived as follows: U Sdown = E down ∑ = E up Π∑ = U Sup ∑ -1 Π∑ = E Sup Ψ where Ψ is a U Sup and U Sdown rotationally invariant relationship, Ψ, Π are similarity matrices; From the properties of similar matrices, we know that the eigenvalues ​​λ of Ψ Ψ The eigenvalue λ of Π Π equal; λ Ψ With the eigenvalues ​​λ of matrix T T satisfy: λ Ψ = z k λ T where λ Ψ is an eigenvalue of Ψ, is the conjugate transpose of U Sup ; When the modulation mode of the polarized emission is determined, the matrix T is no longer changed in the signal processing process, λ T is a determined value; Ψ and T are both 2x2 reversible matrices, there are two eigenvalue pairs corresponding to the same target, the mean value method is adopted to calculate the angle estimation value of the same target; through the calculation of λ Ψ and λ T , z k and 6. The polarized MIMO multi-parameter estimation method based on transmitting polarization modulation according to claim 5, wherein z = mean(λ Ψ / λ T ) where λ T are the eigenvalues of the matrix T, S ok is a 2M x 1 vector, which is rearranged into a 2 x M matrix by column every two elements in order, is a set of 2 x M matrices, whose elements are complex numbers. right The above operation is performed on each column to obtain the DOD estimates for a total of K targets.

7. The transmit polarization modulation based polarization MIMO multi-parameter estimation method according to claim 1, characterized in that, In step S3, the polarized scattering matrix estimation method comprises: Will Rearranged as where (T)7is a mathematical operation (T) n n takes the value of 7, z β is another extended steering vector constructed According to the properties of pseudo-inverse matrix, there exists a matrix such that: the polarization scattering matrix of the kth target is estimated as: S' ok = S ok • [diag{z β}] -1 where is the pseudo-inverse matrix of is the pseudo-inverse matrix of is a set of Mx2 matrices, whose elements are complex numbers; I 2×2 is a 2-order identity matrix; S' ok is S ok · [diag{z β}] -1 is an intermediate variable; diag{} is an operation to convert a vector into a diagonal matrix, z β is the DOD estimation steering vector of the kth target, and is the polarization scattering matrix of the kth target, which is estimated according to the above formula.

8. The transmit polarization modulation based polarization MIMO multi-parameter estimation method according to claim 7, characterized in that, right By operating on each column, we obtain the polarization scattering matrix values ​​for a total of K targets.

9. A polar MIMO multi-parameter estimation system based on transmit polarization modulation, characterized by, The system implements the polarized MIMO multi-parameter estimation method based on transmitting polarization modulation according to any one of claims 1-8, and the system comprises: A polarized multiple-input multiple-output high-frequency ground wave radar array structure composed of a transmitting end and a receiving end; the transmitting end modulates the target signal transmitted by the transmitting elements through a polarization phase controller, and the receiving end receives the echo data of the target after the transmitting polarization modulation, performs pulse compression processing on the echo data, and then reconstructs the echo data; The tensor decomposition module is configured to utilize the reconstructed echo data to construct a third-order tensor form, and perform tensor decomposition on the third-order tensor form by using an alternating least squares method. The multi-parameter joint estimation signal processing module is configured to utilize a multi-parameter joint estimation signal processing method to perform polarization parameter joint estimation based on the result of the tensor decomposition, and output a polarization parameter estimation result.

10. The transmit polarization modulation based polarized MIMO multi-parameter estimation system of claim 9, wherein, The system is loaded on a computer readable storage medium, the computer readable storage medium stores a computer program, and the computer program is executed by a processor to realize the functions of the above method.

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