Array radar forward-looking imaging method and device based on echo signal completion

Abstract

The invention relates to the field of radar imaging technology, and discloses an array radar forward-looking imaging method and device based on echo signal completion. The invention constructs a sparse array radar imaging system, wherein a sparse radar array is randomly distributed in an array plane of the sparse array radar imaging system; collects target echoes and determines whether the target echoes are echoes of a sparse uniform radar array; if not, performs a three-dimensional fast Fourier transform on the target echoes in the sparse array radar imaging system to obtain a target image; if yes, a matrix completion method is used to complete the target echoes; a continuous domain compressed sensing recovery algorithm is used to perform high-resolution solution on the target in each distance unit in the echo signal; and imaging is constructed according to the solution result and the target image is output.

Description

Technical Field

[0001] The present application relates to the field of radar imaging technology, and in particular to an array radar forward-looking imaging method and device based on echo signal completion. Background Art

[0002] Radar high-resolution imaging technology is a widely used remote sensing detection method, playing an important role in geographic observation, environmental monitoring, security alert, etc. The range resolution of radar imaging depends on the signal bandwidth, and the azimuth resolution depends on the antenna aperture. Traditional high-resolution imaging radars rely on synthetic apertures to achieve high-resolution imaging in azimuth, and the relative motion between the radar and the target is a necessary condition for the formation of synthetic apertures. However, in the forward-looking observation imaging scenario, there is no relative rotation between the radar and the target, and the synthetic aperture required by traditional high-resolution imaging radars cannot be formed, and the imaging quality is difficult to guarantee.

[0003] Unlike the side-view imaging method based on synthetic aperture, the real aperture array radar can directly image the target in the forward-view observation scene. Its azimuth resolution depends on the size of the array aperture, more specifically, on the Rayleigh diffraction limit corresponding to the phase center of the antenna array. The real aperture array radar can image the target through the back-projection algorithm. This method is not limited by the shape of the antenna array and has great flexibility in application. However, the disadvantage of this method is that it is computationally intensive and time-consuming, which greatly limits the imaging efficiency of the real aperture array radar.

[0004] By designing a uniform real aperture array and making a far-field approximation of electromagnetic waves, a real aperture array radar can use the fast Fourier transform method to perform fast imaging. The imaging quality of the real aperture array imaging method using fast Fourier transform depends on the main lobe width and side lobe height of the imaging result, more specifically, on the array aperture and the array element spacing. However, on the one hand, it is impossible to increase the radar array aperture indefinitely in practical applications; on the other hand, when the array aperture is constant, a smaller array element spacing means a larger number of array elements, which greatly increases the complexity of the system, while a larger array element spacing will cause higher side lobes and periodic aliasing of the imaging target in azimuth.

[0005] Therefore, how to obtain the same resolution capability as uniform array radar while reducing the complexity of the system has become a technical problem that needs to be solved urgently.

[0006] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0007] The main purpose of the present invention is to provide an array radar forward-looking imaging method and device based on echo signal completion, aiming to solve the technical problem that the prior art cannot reduce the complexity of the system while obtaining a resolution capability comparable to that of a uniform array radar.

[0008] To achieve the above object, the present invention provides an array radar forward-looking imaging method based on echo signal completion, the method comprising:

[0009] Constructing a sparse array radar imaging system, wherein the sparse radar array is randomly distributed in an array plane of the sparse array radar imaging system;

[0010] Collecting a target echo and determining whether the target echo is an echo of a sparse uniform radar array, and if not, performing a three-dimensional fast Fourier transform on the target echo in the sparse array radar imaging system to obtain a target image;

[0011] If yes, the target echo is completed by using a matrix completion method;

[0012] A continuous domain compressed sensing recovery algorithm is used to perform high-resolution analysis on the target within each range unit in the echo signal;

[0013] Construct imaging based on the solution results and output the target image.

[0014] Optionally, the step of constructing a sparse array radar imaging system, wherein the sparse radar array is randomly distributed in an array plane of the sparse array radar imaging system, comprises:

[0015] Construct a sparse array radar imaging system. Assume that the array plane of the radar imaging system includes M columns and N rows of transceiver array element positions. The sparse radar array is randomly distributed in the array plane. The position vector of each transceiver array element can be expressed as The position vector of the target scattering point can be expressed as

[0016] Optionally, the step of collecting the target echo and determining whether the target echo is an echo of a sparse uniform radar array, and if not, performing a three-dimensional fast Fourier transform on the target echo in the sparse array radar imaging system to obtain a target image includes:

[0017] Collecting target echoes, and determining whether the target echoes are echoes of a sparse uniform radar array;

[0018] If not, then the echo of the sparse uniform radar array will be located at (x m ,0,z n ) The target echo received by the array element at position ) is written as:

[0019]

[0020] where o(·) is the target scattering distribution function, is the spatial wave number vector;

[0021] Performing three-dimensional fast Fourier transform on the target echo to obtain a target image.

[0022] Optionally, the step of performing a three-dimensional fast Fourier transform on the target echo to obtain a target image comprises:

[0023] Based on the far-field condition, the target echo can be approximated as follows:

[0024]

[0025] Where k0 = 2π / λ0 represents the center wave number, λ0 is the wavelength corresponding to the center frequency, and s c For three separation variables k, x m and z n Function of

[0026] For the three separation variables k, x m and z n Perform a three-dimensional fast Fourier transform to obtain the target image, namely:

[0027]

[0028] Optionally, if yes, the step of completing the target echo using a matrix completion method includes:

[0029] The matrix completion method is used to complete the sparse radar array signal. Let S p ∈S c N×M For the echo signal s c The pth slice after the distance pulse compression is made, that is,

[0030]

[0031] Define S′ p =S p (Ω) is the corresponding signal of the sparse radar array, Ω is the sparse array element position index, and the block Hankel matrix completion problem in the presence of noise can be written as:

[0032]

[0033] where ||·|| * is the nuclear norm of the matrix, ||·|| F is the Frobenius norm, is the undersampler with reference to Ω, YE is the signal S passing through the uniform radar array p The constructed block Hankel matrix, X E is the signal S′ passing through the sparse radar array p Constructed block Hankel matrix;

[0034] For the block Hankel matrix Y E and the Hankel matrix Y n Solve by finding each Y n The mean of the anti-diagonal elements of the matrix obtains the completed radar array signal.

[0035] Optionally, before the step of using a continuous domain compressed sensing recovery algorithm to perform high-resolution solution on the target within each range unit in the echo signal, the method further includes:

[0036] The pair of echo signals s c The formula for the pth slice after range pulse compression can be written as:

[0037]

[0038] in o(l) is the scattering coefficient of the lth scattering point of the target, for In matrix form, the observation matrix can be written as:

[0039] Y=S p +W

[0040] Where W is the observation noise;

[0041] Solving for S p The regularized objective function is written as:

[0042]

[0043] Optionally, the step of using a continuous domain compressed sensing recovery algorithm to perform high-resolution solution on the target within each range unit in the echo signal includes:

[0044] For the S p The regularized objective function of is solved by the following semi-positive definite problem:

[0045]

[0046] Among them, the frequency combination is solved through the pairing process The scattering point position is determined by the pair of echo signals s c Solve the formula for the pth slice after distance pulse compression:

[0047] Coefficient by Obtained by calculation.

[0048] In addition, to achieve the above-mentioned purpose, the present invention also proposes an array radar forward-looking imaging device based on echo signal completion, the device comprising:

[0049] A system building module, used for building a sparse array radar imaging system, wherein the sparse radar array is randomly distributed in an array plane of the sparse array radar imaging system;

[0050] a non-sparse derivation module, used for collecting target echoes and determining whether the target echoes are echoes of a sparse uniform radar array, and if not, performing a three-dimensional fast Fourier transform on the target echoes in the sparse array radar imaging system to obtain a target image;

[0051] A matrix completion module, for completing the target echo using a matrix completion method if yes;

[0052] A compressed sensing module, used for performing high-resolution solution of the target within each range unit in the echo signal by using a continuous domain compressed sensing recovery algorithm;

[0053] The output module is used to construct imaging according to the solution results and output the target image.

[0054] In addition, to achieve the above-mentioned purpose, the present invention also proposes an array radar forward-looking imaging device based on echo signal completion, the device comprising: a memory, a processor, and an array radar forward-looking imaging program based on echo signal completion stored in the memory and executable on the processor, the array radar forward-looking imaging program based on echo signal completion being configured to implement the steps of the array radar forward-looking imaging method based on echo signal completion as described above.

[0055] In addition, to achieve the above-mentioned purpose, the present invention also proposes a medium, on which is stored an array radar forward-looking imaging program based on echo signal completion. When the array radar forward-looking imaging program based on echo signal completion is executed by a processor, the steps of the array radar forward-looking imaging method based on echo signal completion as described above are implemented.

[0056] The present invention constructs a sparse array radar imaging system, wherein a sparse radar array is randomly distributed in an array plane of the sparse array radar imaging system; collects target echoes and determines whether the target echoes are echoes of a sparse uniform radar array; if not, performs a three-dimensional fast Fourier transform on the target echoes in the sparse array radar imaging system to obtain a target image; if yes, a matrix completion method is used to complete the target echoes; a continuous domain compressed sensing recovery algorithm is used to perform high-resolution solution on the target in each distance unit in the echo signal; an imaging is constructed according to the solution result and the target image is output; the signal of the sparse array radar is completed by matrix completion, thereby obtaining a resolution capability equivalent to that of a uniform array radar while greatly reducing the complexity of the system; and the imaging target is solved and reconstructed by a two-dimensional atomic norm minimization method. The two-dimensional atomic norm minimization method can solve and obtain an accurate main lobe peak value, and the main lobe is infinitely narrow in theory, and the method can greatly reduce the side lobe height, thereby improving the imaging quality, and effectively solving the problem of limited forward imaging quality of the array radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a structural schematic diagram of an array radar forward-looking imaging device based on echo signal completion in a hardware operating environment involved in an embodiment of the present invention;

[0058] Figure 2 It is a flow chart of a first embodiment of an array radar forward-looking imaging method based on echo signal completion according to the present invention;

[0059] Figure 3 It is a scene diagram of array radar forward-looking imaging based on continuous domain compressed sensing of the first embodiment of the array radar forward-looking imaging method based on echo signal completion of the present invention;

[0060] Figure 4 It is a schematic diagram of a uniform array and a sparse array in the first embodiment of the array radar forward imaging method based on echo signal completion of the present invention;

[0061] Figure 5 It is the imaging result of the method described in the first embodiment of the array radar forward-looking imaging method based on echo signal completion of the present invention, the sparse array echo three-dimensional fast Fourier transform, and the completed array echo three-dimensional fast Fourier transform. DETAILED DESCRIPTION

[0062] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0063] Reference Figure 1 , Figure 1 The present invention is a schematic diagram of the structure of an array radar forward-looking imaging device based on echo signal completion in the hardware operating environment involved in the embodiment of the present invention.

[0064] like Figure 1 As shown, the array radar forward-looking imaging device based on echo signal completion may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a wireless fidelity (Wireless-Fidelity, WI-FI) interface). The memory 1005 may be a high-speed random access memory (Random Access Memory, RAM) memory, or a stable non-volatile memory (Non-Volatile Memory, NVM), such as a disk memory. The memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0065] Those skilled in the art will understand that Figure 1 The structure shown in the figure does not constitute a limitation on the array radar forward-looking imaging device based on echo signal completion, and may include more or less components than those shown in the figure, or a combination of certain components, or a different arrangement of components.

[0066] like Figure 1 As shown, the memory 1005 as a storage medium may include an operating system, a data storage module, a network communication module, a user interface module, and an array radar forward-looking imaging program based on echo signal completion.

[0067] exist Figure 1 In the array radar forward-looking imaging device based on echo signal completion shown, the network interface 1004 is mainly used for data communication with a network server; the user interface 1003 is mainly used for data interaction with a user; the processor 1001 and the memory 1005 in the array radar forward-looking imaging device based on echo signal completion of the present invention can be set in the array radar forward-looking imaging device based on echo signal completion, and the array radar forward-looking imaging device based on echo signal completion calls the array radar forward-looking imaging program based on echo signal completion stored in the memory 1005 through the processor 1001, and executes the array radar forward-looking imaging method based on echo signal completion provided in an embodiment of the present invention.

[0068] The embodiment of the present invention provides an array radar forward imaging method based on echo signal completion, referring to Figure 2 , Figure 2 The figure is a flow chart of the first embodiment of the array radar forward-looking imaging method based on echo signal completion of the present invention.

[0069] In this embodiment, the array radar forward-looking imaging method based on echo signal completion includes the following steps:

[0070] Step S10: constructing a sparse array radar imaging system, wherein the sparse radar arrays are randomly distributed in an array plane of the sparse array radar imaging system.

[0071] It should be noted that, refer to Figure 3 , assuming that the array plane of the radar imaging system includes M columns and N rows of transceiver array element positions, and the sparse radar array is randomly distributed in the array plane. The position vector of each transceiver array element can be expressed as The position vector of the target scattering point can be expressed as

[0072] Furthermore, the step of constructing a sparse array radar imaging system, wherein the sparse radar array is randomly distributed in an array plane of the sparse array radar imaging system, comprises: constructing a sparse array radar imaging system, assuming that the array plane of the radar imaging system includes M columns and N rows of transceiver array element positions, the sparse radar array is randomly distributed in the array plane, and the position vector of each transceiver array element can be expressed as The position vector of the target scattering point can be expressed as

[0073] Step S20: collecting target echoes and determining whether the target echoes are echoes of a sparse uniform radar array; if not, performing a three-dimensional fast Fourier transform on the target echoes in the sparse array radar imaging system to obtain a target image.

[0074] In the specific implementation, the target echo is collected. First, the echo of the non-sparse uniform radar array is derived. Ignoring the amplitude attenuation in signal propagation, the m ,0,z n ) The target echo received by the array element at can be written as:

[0075]

[0076] where o(·) is the target scattering distribution function, is the spatial wave number vector. The reference signal with an amplitude of 1 at (0,y0,0) can be written as

[0077]

[0078] Then the echo signal after correcting the reference distance can be written as

[0079]

[0080] Among them, y′1=y′-y0, and there is

[0081]

[0082] The above formula is based on the plane wave approximation under far-field conditions, that is, y0>>x m ,z n ,x,z. k=2π / λ is the spatial wave number, λ is the wavelength. Substituting equation (4) into equation (3) yields:

[0083]

[0084] Where k0 = 2π / λ0 represents the center wave number, and λ0 is the wavelength corresponding to the center frequency. In formula (5), s c For three separation variables k, x m and z n Therefore, a three-dimensional fast Fourier transform can be performed on the three variables to obtain the target image, namely:

[0085]

[0086] However, formula (6) is derived based on a non-sparse uniform radar array. When the radar array is sparse, formula (6) cannot be directly applied.

[0087] Further, the step of collecting target echoes and determining whether the target echoes are echoes of a sparse uniform radar array, and if not, performing a three-dimensional fast Fourier transform on the target echoes in the sparse array radar imaging system to obtain a target image, comprises: collecting target echoes, determining whether the target echoes are echoes of a sparse uniform radar array; if not, deriving an echo of a non-sparse uniform radar array, and converting the target image to an image of the target. m ,0,z n ) The target echo received by the array element at position ) is written as:

[0088]

[0089] where o(·) is the target scattering distribution function, is a spatial wave number vector; a three-dimensional fast Fourier transform is performed on the target echo to obtain a target image.

[0090] Furthermore, the step of performing a three-dimensional fast Fourier transform on the target echo to obtain a target image includes:

[0091] Based on the far-field condition, the target echo can be approximated as follows:

[0092]

[0093] Where k0 = 2π / λ0 represents the center wave number, λ0 is the wavelength corresponding to the center frequency, and s c For three separation variables k, x m and z n function; for the three separation variables k, x m and z n Perform a three-dimensional fast Fourier transform to obtain the target image, namely:

[0094]

[0095] Step S30: If yes, the target echo is completed using a matrix completion method.

[0096] In the specific implementation, the sparse radar array echo signal is completed. Based on the Toeplitz matrix characteristics and Hankel matrix characteristics of the uniform array echo signal, the sparse radar array signal can be completed by using the matrix completion method. Assume S p ∈s c N × M For the echo signal s c The pth slice after the distance pulse compression is made, that is,

[0097]

[0098] Reference Figure 4 , define S′ p =S p (Ω) is the corresponding signal of the sparse radar array, and Ω is the sparse array element position index. Then S′ p Can be regarded as S p According to the undersampling result of Ω, the missing elements can be recovered by solving a relaxed nuclear norm optimization problem. The block Hankel matrix completion problem in the presence of noise can be written as:

[0099]

[0100] where ||·|| * is the nuclear norm of the matrix, ||·|| F is the Frobenius norm, is the undersampler with reference to Ω, Y E is the signal S passing through the uniform radar array p The constructed block Hankel matrix, X E is the signal S′ passing through the sparse radar array p The block Hankel matrix constructed. The form of the block Hankel matrix can be written as:

[0101]

[0102] where Y n is the Hankel matrix, which is composed of the signals corresponding to the nth row of the radar array, that is,

[0103]

[0104] Obtain the block Hankel matrix Y E and the Hankel matrix Y n After that, the completed radar array signal can be obtained by finding each Y n The mean of the anti-diagonal elements of the matrix is ​​obtained. Through the above method, the sparse radar array echo signal can be completed.

[0105] Furthermore, if the step of using a matrix completion method to complete the target echo comprises: using a matrix completion method to complete the sparse radar array signal, assuming S p ∈S c N×M For the echo signal s c The pth slice after the distance pulse compression is made, that is,

[0106]

[0107] Define S′ p =S p (Ω) is the corresponding signal of the sparse radar array, Ω is the sparse array element position index, and the block Hankel matrix completion problem in the presence of noise can be written as:

[0108]

[0109] where ||·|| * is the nuclear norm of the matrix, ||·|| F is the Frobenius norm, is the undersampler with reference to Ω, Y E is the signal S passing through the uniform radar array p The constructed block Hankel matrix, X E is the signal S′ passing through the sparse radar array p Constructed block Hankel matrix; for the block Hankel matrix Y E and the Hankel matrix Y n Solve by finding each Y n The mean of the anti-diagonal elements of the matrix obtains the completed radar array signal.

[0110] Step S40: using a continuous domain compressed sensing recovery algorithm to perform high-resolution analysis on the target within each range unit in the echo signal.

[0111] In the specific implementation, each distance unit is solved in two dimensions with high resolution. Equation (7) can be written in discrete form:

[0112]

[0113] in

[0114]

[0115] The matrix form of formula (11) can be written as

[0116]

[0117] in o(l) is the scattering coefficient of the lth scattering point of the target, for in matrix form, and

[0118]

[0119] Then the observation matrix can be written as

[0120] Y=S p +W (15)

[0121] Where W is the observation noise. The atomic norm minimization method is a continuous domain compressed sensing recovery algorithm, which defines the continuous atomic basis sequence as

[0122]

[0123] where {a(f)} n =exp(j(2πfn)), n=1,2,...,N is the nth element of a(f). The matrix form of the two-dimensional atomic basis can be written as

[0124]

[0125] Then the matrix atomic norm of equation (13) can be written as

[0126]

[0127] Solving for S p The regularized objective function can be written as

[0128]

[0129] Formula (19) can be solved by solving the following semi-positive definite problem:

[0130]

[0131] in and are called first-order Hermitian Toeplitz matrices, and their first rows correspond to and After solving equation (20), the estimated and And the corresponding and It can be obtained by first-order Vandermonde decomposition, that is

[0132]

[0133] Since the final goal is to find the two-dimensional coordinates of the scattering points, the frequency combination needs to be solved through a pairing process. From formula (13), we can get:

[0134]

[0135] in Denotes the pseudo-inverse. Definition If the element If the value of exceeds a certain threshold δ∈(0,1), it means that it corresponds to a set of frequency combinations The corresponding scattering point positions and coefficients can be expressed by equations (12) and get.

[0136] Furthermore, before the step of using the continuous domain compressed sensing recovery algorithm to perform high-resolution solution on the target within each distance unit in the echo signal, the method further includes: c The formula for the pth slice after range pulse compression can be written as:

[0137]

[0138] in o(l) is the scattering coefficient of the lth scattering point of the target, for In matrix form, the observation matrix can be written as:

[0139] Y=S p +W

[0140] Where W is the observation noise; solve S p The regularized objective function is written as:

[0141]

[0142] Furthermore, the step of using the continuous domain compressed sensing recovery algorithm to perform high-resolution solution on the target within each distance unit in the echo signal includes:p The regularized objective function of is solved by the following semi-positive definite problem:

[0143]

[0144] Among them, the frequency combination is solved through the pairing process The scattering point position is determined by the pair of echo signal numbers s c Solve the formula for the pth slice after distance pulse compression:

[0145]

[0146] The coefficient is calculated by get.

[0147] Step S50: construct imaging according to the solution result and output the target image.

[0148] Understandably, Figure 5 It is the numerical simulation imaging result of the method described in this embodiment, the sparse array echo three-dimensional fast Fourier transform, and the complementary array echo three-dimensional fast Fourier transform. The transmitting and receiving array elements are shared in working mode. The overall aperture of the radar array is 0.35m×0.35m, the number of complete array elements is 16×16, and the number of array elements in the sparse array is 36, that is, the number of sparse array elements accounts for about 14% of the total number of array elements. The radar array is used to transmit stepped frequency modulated electromagnetic waves, the transmission signal carrier frequency is 34GHz, the bandwidth is 1GHz, the target distance is 100m, and the imaging signal-to-noise ratio SNR=20dB. Figure 5 (a) is a three-dimensional imaging target, which includes several scattering points. Figure 5 (b) Imaging results of 3D fast Fourier transform of sparse array echoes. Figure 5 (c) Imaging results of 3D fast Fourier transform of the complement array echo. Figure 5 (d) is the imaging result based on continuous domain compressed sensing described in the present invention. It can be seen from the figure that the method described in the present invention can effectively improve the imaging quality.

[0149] In this embodiment, a sparse array radar imaging system is constructed, and a sparse radar array is randomly distributed in an array plane of the sparse array radar imaging system; a target echo is collected and it is determined whether the target echo is an echo of a sparse uniform radar array. If not, a three-dimensional fast Fourier transform is performed on the target echo in the sparse array radar imaging system to obtain a target image; if so, a matrix completion method is used to complete the target echo; a continuous domain compressed sensing recovery algorithm is used to perform a high-resolution solution for the target in each distance unit in the echo signal; an imaging is constructed according to the solution result and a target image is output, and the signal of the sparse array radar is completed by matrix completion, thereby obtaining a resolution capability equivalent to that of a uniform array radar while greatly reducing the complexity of the system, and at the same time, the imaging target is solved and reconstructed by a two-dimensional atomic norm minimization method, and the two-dimensional atomic norm minimization method can solve and obtain an accurate main lobe peak value. Theoretically, the main lobe is infinitely narrow, and the method can greatly reduce the sidelobe height, thereby improving the imaging quality, and effectively solving the problem of limited forward imaging quality of array radar.

[0150] In addition, an embodiment of the present invention also proposes a medium, on which is stored an array radar forward-looking imaging program based on echo signal completion. When the array radar forward-looking imaging program based on echo signal completion is executed by a processor, the steps of the array radar forward-looking imaging method based on echo signal completion as described above are implemented.

[0151] The embodiments or specific implementation methods of the array radar forward-looking imaging device based on echo signal completion of the present invention can refer to the above-mentioned method embodiments, which will not be repeated here.

[0152] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0153] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0154] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory / random access memory, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0155] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A forward-looking imaging method for array radar based on echo signal completion, characterized in that: The method comprises: Constructing a sparse array radar imaging system, wherein the sparse radar array is randomly distributed in an array plane of the sparse array radar imaging system; Collecting a target echo and determining whether the target echo is an echo of a sparse uniform radar array, and if not, performing a three-dimensional fast Fourier transform on the target echo in the sparse array radar imaging system to obtain a target image; If yes, the target echo is completed by using a matrix completion method; A continuous domain compressed sensing recovery algorithm is used to perform high-resolution analysis on the target within each range unit in the echo signal; Construct imaging according to the solution results and output the target image; If so, the step of completing the target echo using a matrix completion method comprises: The matrix completion method is used to complete the sparse radar array signal. For the echo signal After distance pulse compression slices, i.e. ； definition is the corresponding signal of the sparse radar array, is the sparse array element position index, the block Hankel matrix completion problem in the presence of noise can be written as: ； in is the nuclear norm of the matrix, is the Frobenius norm, For reference The undersampler, is the signal passing through the uniform radar array The block Hankel matrix constructed is, is the signal passing through the sparse radar array Constructed block Hankel matrix; For the block Hankel matrix and the Hankel matrix To solve, by finding each The mean of the anti-diagonal elements of the matrix obtains the completed radar array signal; Before the step of using the continuous domain compressed sensing recovery algorithm to perform high-resolution solution on the target within each distance unit in the echo signal, the method further includes: The pair of echo signals After distance pulse compression The formula for a slice can be written as: ； in , is the scattering coefficient of the target’s lth scattering point, for In matrix form, the observation matrix can be written as: in is the observation noise; Solution The regularized objective function is written as: 。 2. The method according to claim 1, characterized in that The step of constructing a sparse array radar imaging system, wherein the sparse radar array is randomly distributed in an array plane of the sparse array radar imaging system, comprises: Construct a sparse array radar imaging system. Assume that the array plane of the radar imaging system includes M columns and N rows of transceiver array element positions. The sparse radar array is randomly distributed in the array plane. The position vector of each transceiver array element can be expressed as , the position vector of the target scattering point can be expressed as .

3. The method according to claim 2, characterized in that The step of collecting the target echo and determining whether the target echo is an echo of a sparse uniform radar array, and if not, performing a three-dimensional fast Fourier transform on the target echo in the sparse array radar imaging system to obtain a target image comprises: Collecting target echoes, and determining whether the target echoes are echoes of a sparse uniform radar array; If not, the return of the non-sparse uniform radar array is derived to be located at The target echo received by the array element at is written as: ； in is the target scattering distribution function, is the spatial wave number vector; Performing three-dimensional fast Fourier transform on the target echo to obtain a target image.

4. The method according to claim 3, characterized in that The step of performing a three-dimensional fast Fourier transform on the target echo to obtain a target image comprises: Based on the far-field condition, the target echo can be approximated as follows: ； in, represents the central wave number, is the wavelength corresponding to the center frequency, For three separate variables , and Function of For the three separation variables , and Perform a three-dimensional fast Fourier transform to obtain the target image, namely: 。 5. The method according to claim 1, characterized in that The step of using a continuous domain compressed sensing recovery algorithm to perform high-resolution solution on the target within each range unit in the echo signal comprises: Regarding the The regularized objective function of is solved by the following semi-positive definite problem: Among them, the frequency combination is solved through the pairing process ; The scattering point position is determined by the pair of echo signals After distance pulse compression The formula for each slice is solved: ； Coefficient by Obtained by calculation.

6. An array radar forward-looking imaging device based on echo signal completion, characterized in that: The device comprises: A system building module, used for building a sparse array radar imaging system, wherein the sparse radar array is randomly distributed in an array plane of the sparse array radar imaging system; a non-sparse derivation module, used for collecting target echoes and determining whether the target echoes are echoes of a sparse uniform radar array, and if not, performing a three-dimensional fast Fourier transform on the target echoes in the sparse array radar imaging system to obtain a target image; A matrix completion module, for completing the target echo using a matrix completion method if yes; A compressed sensing module, used for performing high-resolution solution of the target within each range unit in the echo signal by using a continuous domain compressed sensing recovery algorithm; An output module is used to construct an image based on the solution result and output a target image; If so, the step of completing the target echo using a matrix completion method comprises: The matrix completion method is used to complete the sparse radar array signal. For the echo signal After distance pulse compression slices, i.e. ； definition is the corresponding signal of the sparse radar array, is the sparse array element position index, the block Hankel matrix completion problem in the presence of noise can be written as: ； in is the nuclear norm of the matrix, is the Frobenius norm, For reference The undersampler, is the signal passing through the uniform radar array The block Hankel matrix constructed is, is the signal passing through the sparse radar array Constructed block Hankel matrix; For the block Hankel matrix and the Hankel matrix To solve, by finding each The mean of the anti-diagonal elements of the matrix obtains the completed radar array signal; Before the step of using the continuous domain compressed sensing recovery algorithm to perform high-resolution solution on the target within each distance unit in the echo signal, the method further includes: The pair of echo signals After distance pulse compression The formula for a slice can be written as: ； in , is the scattering coefficient of the target’s lth scattering point, for In matrix form, the observation matrix can be written as: in is the observation noise; Solution The regularized objective function is written as: 。 7. An array radar forward-looking imaging device based on echo signal completion, characterized in that: The device includes: a memory, a processor, and an array radar forward-looking imaging program based on echo signal completion stored in the memory and executable on the processor, wherein the array radar forward-looking imaging program based on echo signal completion is configured to implement the steps of the array radar forward-looking imaging method based on echo signal completion as described in any one of claims 1 to 5.

8. A computer storage medium, characterized in that The medium stores an array radar forward-looking imaging program based on echo signal completion, and when the array radar forward-looking imaging program based on echo signal completion is executed by the processor, the steps of the array radar forward-looking imaging method based on echo signal completion as described in any one of claims 1 to 5 are implemented.

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