A method for locating surface earthquake sources with unknown wave velocity based on broadband focused beamforming

Abstract

The invention discloses a method for locating a surface earthquake source of unknown wave velocity based on broadband focused beamforming. The invention can realize accurate positioning of a ground earthquake source without relying on prior knowledge of surface wave velocity, and can provide an estimated value of the surface wave velocity. By calculating a frequency domain data matrix based on an FFT algorithm, calculating an effective frequency domain subband range, and intercepting the frequency domain data matrix, the signal-to-noise ratio of a received signal is greatly improved, the influence of noise on the target positioning accuracy is effectively reduced, and the final positioning performance is helped to be improved. The calculated output power of a beamformer includes the power of all frequency components of a seismic surface wave signal, and the processing gain of the system is greatly improved, thereby helping to improve the target positioning accuracy and the target detection distance.

Description

Technical Field

[0001] The present invention relates to the field of digital signal technology, and in particular to a method, system, terminal and computer-readable storage medium for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming. Background Art

[0002] A typical passive positioning method is triangulation positioning (also known as multi-platform positioning technology), which uses two base arrays separated by a certain distance to measure the azimuth of the same target, and then estimates the distance of the target based on the triangulation relationship. Triangulation positioning is simple and direct, but it is very sensitive to azimuth accuracy, resulting in poor ranging accuracy and robustness.

[0003] The positioning method based on delay estimation is also a relatively common passive positioning method. Its basic principle is to place three equally spaced array elements (or sub-arrays) on a straight line. By measuring the delay difference between the target signal reaching the first and second array elements, as well as the delay difference between the second and third array elements, the distance and azimuth from the target to the center array element can be calculated. The main factor affecting the ranging accuracy of the three-point positioning method is the delay measurement error. When the delay measurement error is constant, if the target is farther away, the delay difference is smaller and the ranging error is larger. In addition, the above positioning method usually requires knowing the surface wave propagation velocity in advance before implementation, which also brings certain difficulties to the actual application of engineering.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] The main purpose of the present invention is to provide a method, system, terminal and computer-readable storage medium for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming, aiming to solve the problem in the prior art that the positioning of ground vibration sources requires reliance on prior knowledge of surface wave velocity and the positioning is inaccurate.

[0006] To achieve the above object, the present invention provides a method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming, and the method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming comprises the following steps:

[0007] Collect the received signals of all sensors in the array and construct a time domain data matrix;

[0008] Calculating the time domain data matrix based on a fast Fourier transform algorithm to obtain a frequency domain data matrix;

[0009] Calculating an effective frequency domain sub-band range according to existing geological exploration data, and intercepting the frequency domain data matrix according to the effective frequency domain sub-band range;

[0010] Selecting the initial values ​​of the surface wave propagation velocity, the scanning distance and the scanning angle, and calculating the distance from the scanning point to each sensor of the array, the beamformer weighting matrix and the beamformer output power in turn;

[0011] Repeatedly select different scanning distances and scanning angles, repeatedly calculate the output power of the beamformer at all scanning distances and scanning angles, and form a spatial power scanning diagram;

[0012] Searching the spatial power scan graph to obtain a maximum power point in the spatial power scan graph, and a scan distance and a scan angle corresponding to the maximum power point;

[0013] Repeatedly select different surface wave propagation velocities to obtain the maximum power point under all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point, to form a data processing result matrix;

[0014] The data in the data processing result matrix are compared and analyzed to obtain the estimated value of the surface wave velocity and the coordinate value of the ground vibration source target in the coordinate system.

[0015] The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming, wherein the receiving signals of all sensors in the acquisition array and the construction of a time domain data matrix specifically include:

[0016] Collect and store the received signals of all sensors in the array, and construct the time domain data matrix X as follows:

[0017]

[0018] Where N represents the number of array elements, L represents the data length of the signal received by a single sensor array element, and x i (j) represents the received data of the i-th array element at the j-th time, and i represents one of N.

[0019] The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming, wherein the array is composed of a plurality of vibration sensors arranged according to a certain spatial pattern; the vibration sensor is a velocity sensor used to measure the vibration velocity of a medium.

[0020] The unknown wave velocity surface earthquake source positioning method based on broadband focused beamforming, wherein the time domain data matrix is ​​calculated based on the fast Fourier transform algorithm to obtain the frequency domain data matrix, specifically comprising:

[0021] Based on the fast Fourier transform algorithm, each row of the time domain data matrix X is subjected to a discrete Fourier transform of L points:

[0022]

[0023] Among them, X m (k) represents the FFT transform form corresponding to each element in the time domain data matrix X, l represents the index number after discrete sampling of the time domain signal; k represents the frequency domain subband number, and the value range is k=0,1,…L-1; m represents the sensor array element number, and the value range is k=0,1,…N-1;

[0024] Using all discrete Fourier transform results, construct the frequency domain data matrix X f :

[0025]

[0026] The unknown wave velocity surface earthquake source positioning method based on broadband focused beamforming, wherein the effective frequency domain sub-band range is calculated according to the existing geological exploration data, and the frequency domain data matrix is ​​intercepted according to the effective frequency domain sub-band range, specifically comprising:

[0027] According to the existing geological exploration data, the frequency range of the seismic surface wave signal is determined and recorded as [f l ,f p ], where f l Represents the lower frequency limit of the seismic surface wave signal, in Hz; f p Represents the upper frequency limit of the seismic surface wave signal, in Hz;

[0028] The frequency range of the seismic surface wave signal is converted into an effective frequency domain subband range [k l ,k p ], the specific conversion is as follows:

[0029]

[0030] The symbol [·] represents rounding operation, f s Represents the signal sampling frequency in Hz;

[0031] According to the effective frequency domain subband range [k l ,k p ], for the frequency domain data matrix X f The frequency domain data matrix after interception is recorded as

[0032]

[0033] The unknown wave velocity surface earthquake source location method based on broadband focused beamforming, wherein the initial value of the surface wave propagation velocity, the initial value of the scanning distance and the initial value of the scanning angle are selected, and the distance from the scanning point to each sensor of the array, the beamformer weighting matrix and the beamformer output power are calculated in sequence, specifically including:

[0034] Select the initial value of the surface wave propagation velocity, denoted as c=c1, where c represents the surface wave velocity, and c1 represents the given initial value of the surface wave propagation velocity, in units of m / s;

[0035] Select the initial value of the scanning distance and the initial value of the scanning angle, which are denoted as r=r1 and θ=θ1 respectively, where the scanning distance r represents the distance from the scanning point to the origin of the coordinate system, in meters, and the scanning angle θ represents the angle from the coordinate system y to the scanning point clockwise, in degrees, and r1 and θ1 represent the given initial values ​​of the scanning distance and scanning angle;

[0036] Calculate the distance from the scanning point to each sensor in the array:

[0037]

[0038] Among them, x i and i Respectively represent the x-coordinate and y-coordinate of the i-th sensor in the coordinate system;

[0039] Compute the beamformer weight matrix:

[0040]

[0041] Calculate the beamformer output power:

[0042]

[0043] in, represents the Hadamard product, the symbol * represents the conjugate operation of the matrix, the symbol H represents the conjugate transpose operation of the matrix, and the symbol tr represents the trace operation of the matrix.

[0044] The unknown wave velocity surface earthquake source positioning method based on broadband focused beamforming, wherein the repeatedly selecting different scanning distances and scanning angles, repeatedly calculating the beamformer output power at all scanning distances and scanning angles, and forming a spatial power scanning diagram, specifically includes:

[0045] Repeatedly select different scanning distances and scanning angles, denoted as r = r i and θ = θ i , repeatedly calculating the distance from the scanning point to each sensor in the array, the beamformer weighting matrix, and the beamformer output power;

[0046] The output power of the beamformer at all scanning distances and scanning angles is obtained according to the calculation results, and a spatial power scanning diagram is formed.

[0047] The unknown wave velocity surface earthquake source positioning method based on broadband focused beamforming, wherein the repeated selection of different surface wave propagation velocities to obtain the maximum power point under all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point, to form a data processing result matrix, specifically includes:

[0048] Repeatedly select different surface wave propagation velocities, denoted as c = c i , repeatedly calculate to obtain the maximum power point at all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point;

[0049] The results are saved in the data processing result matrix R. The data processing result matrix R is:

[0050]

[0051] Wherein, P1 represents the maximum power obtained when the surface wave propagation velocity c1 is selected, r1 and θ1 represent the scanning distance and scanning angle corresponding to the maximum power point when the surface wave propagation velocity c1 is selected; P2 represents the maximum power obtained when the surface wave propagation velocity c2 is selected, r2 and θ2 represent the scanning distance and scanning angle corresponding to the maximum power point when the surface wave propagation velocity c2 is selected; P d It means that when the surface wave propagation velocity c is selected d The maximum power obtained when d and θ d They represent the surface wave propagation velocity c when d The scanning distance and scanning angle corresponding to the maximum power point.

[0052] The unknown wave velocity surface earthquake source positioning method based on broadband focused beamforming, wherein the data in the data processing result matrix is ​​compared and analyzed to obtain the surface wave velocity estimation value and the coordinate value of the ground vibration source target in the coordinate system, specifically includes:

[0053] Compare the first column of the data processing result matrix R and determine the row number where the maximum value in the first column of data is located, denoted as g. Finally, c in the gth row of the data processing result matrix R is g As the surface wave velocity estimate, according to the data processing result matrix R in the g-th row, g and θ g Calculate the x-coordinate value and y-coordinate value of the ground vibration source target in the coordinate system, that is:

[0054] x=r g sinθ g , x = r g cosθ g .

[0055] In the method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming, the calculated output power of the beamformer includes the power of all frequency components of the seismic surface wave signal.

[0056] In addition, to achieve the above-mentioned purpose, the present invention also provides an unknown wave velocity surface source positioning system based on broadband focused beamforming, wherein the unknown wave velocity surface source positioning system based on broadband focused beamforming comprises:

[0057] The signal acquisition module is used to collect the received signals of all sensors in the array and construct a time domain data matrix;

[0058] A time domain calculation module, used for calculating the time domain data matrix based on a fast Fourier transform algorithm to obtain a frequency domain data matrix;

[0059] A frequency domain interception module, used to calculate the effective frequency domain sub-band range according to the existing geological exploration data, and intercept the frequency domain data matrix according to the effective frequency domain sub-band range;

[0060] A parameter calculation module is used to select an initial value of the surface wave propagation velocity, an initial value of the scanning distance, and an initial value of the scanning angle, and to sequentially calculate the distance from the scanning point to each sensor of the array, a beamformer weighting matrix, and a beamformer output power;

[0061] A spatial power scan diagram forming module, used for repeatedly selecting different scanning distances and scanning angles, repeatedly calculating the output power of the beamformer at all scanning distances and scanning angles, and forming a spatial power scan diagram;

[0062] A spatial power scanning diagram search module, used to search the spatial power scanning diagram to obtain the maximum power point in the spatial power scanning diagram, and the scanning distance and scanning angle corresponding to the maximum power point;

[0063] The data processing result matrix forming module is used to repeatedly select different surface wave propagation velocities to obtain the maximum power point under all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point, to form a data processing result matrix;

[0064] The coordinate calculation module is used to compare and analyze the data in the data processing result matrix to obtain the estimated value of the surface wave velocity and the coordinate value of the ground vibration source target in the coordinate system.

[0065] In addition, to achieve the above-mentioned purpose, the present invention also provides a terminal, wherein the terminal includes: a memory, a processor, and an unknown wave velocity surface earthquake source locating program based on broadband focused beamforming stored in the memory and executable on the processor, wherein the unknown wave velocity surface earthquake source locating program based on broadband focused beamforming, when executed by the processor, implements the steps of the unknown wave velocity surface earthquake source locating method based on broadband focused beamforming as described above.

[0066] In addition, to achieve the above-mentioned purpose, the present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores an unknown wave velocity surface seismic source locating program based on broadband focused beamforming, and when the unknown wave velocity surface seismic source locating program based on broadband focused beamforming is executed by a processor, the steps of the unknown wave velocity surface seismic source locating method based on broadband focused beamforming as described above are implemented.

[0067] The present invention introduces the inverted index structure in the traditional database into the distributed computing framework, realizes the distributed partitioning of document similarity detection, and realizes the distributed computing of Simhash technology through the inverted table partitioning method, bringing it scalability. Finally, by embedding the prefix pruning technology in the traditional database field in the calculation process, the communication reading and writing costs of the inverted partitioning and the verification cost of the Simhash calculation in the distributed duplicate detection process are further reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a flow chart of a preferred embodiment of the method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming of the present invention;

[0069] Figure 2 It is a flow chart of the entire execution process in a preferred embodiment of the method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming of the present invention;

[0070] Figure 3 It is a schematic diagram of the principle of a preferred embodiment of the unknown wave velocity surface earthquake source positioning system based on broadband focused beamforming of the present invention;

[0071] Figure 4 Schematic diagram of the operating environment of a preferred embodiment of the terminal of the present invention. DETAILED DESCRIPTION

[0072] In order to make the purpose, technical solution and advantages of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples. 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.

[0073] The unknown wave velocity surface earthquake source positioning method based on broadband focused beamforming described in the preferred embodiment of the present invention is as follows: Figure 1 and Figure 2 As shown, the unknown wave velocity surface earthquake source positioning method based on broadband focused beamforming includes the following steps:

[0074] Step S10: collecting received signals of all sensors in the array and constructing a time domain data matrix.

[0075] Specifically, the array is composed of multiple vibration sensors arranged according to a certain spatial pattern, such as an equidistant linear array (the spacing between each sensor is the same and arranged in a straight line). The sensor receives the vibration signal of the formation. The vibration sensor is a velocity sensor used to measure the vibration velocity of the medium.

[0076] The received signals of all sensors in the array are collected and stored, and the time domain data matrix X is constructed as:

[0077]

[0078] Where N represents the number of array elements, L represents the data length of the signal received by a single sensor array element, and x i (j) represents the received data of the i-th array element at the j-th time, and i represents one of N.

[0079] Step S20: Calculate the time domain data matrix based on a fast Fourier transform algorithm to obtain a frequency domain data matrix.

[0080] Specifically, based on the fast Fourier transform algorithm (FFT algorithm), each row of the time domain data matrix X is subjected to a discrete Fourier transform of L points:

[0081]

[0082] Among them, X m (k) represents the FFT transform form corresponding to each element in the time domain data matrix X; l represents the index number after discrete sampling of the time domain signal, corresponding to an element in any row of the time domain data matrix X, such as when l=2, corresponding to x n (2), where n ranges from 1 to N; k represents the frequency domain subband number, ranging from k = 0, 1, ... L-1; m represents the sensor array element number, ranging from k = 0, 1, ... N-1.

[0083] The Fast Fourier Transform (FFT) algorithm can be used to complete the above discrete Fourier transform more quickly. In this case, the data length needs to be limited to an integer power of 2, that is, L = 2 M , where M is a positive integer, and its specific size can be determined according to actual conditions.

[0084] Then, using all the above discrete Fourier transform results, construct the frequency domain data matrix X f :

[0085]

[0086] Step S30: Calculate the effective frequency domain sub-band range according to the existing geological exploration data, and intercept the frequency domain data matrix according to the effective frequency domain sub-band range.

[0087] Specifically, according to the existing geological exploration data (geological exploration data is determined by the type of rock and soil on site. When the type of rock and soil is known, geological literature can be consulted to obtain the propagation characteristics of seismic waves in the medium, and then the effective frequency range of seismic waves can be obtained), the frequency range of the seismic surface wave signal is determined, which is denoted as [f l ,f p ], where f l Represents the lower frequency limit of the seismic surface wave signal, in Hz; f p Represents the upper frequency limit of the seismic surface wave signal, in Hz;

[0088] Then, the frequency range of the seismic surface wave signal is converted into the effective frequency domain sub-band range [k l ,k p ], the specific conversion is as follows:

[0089]

[0090] The symbol [·] represents rounding operation, f s Represents the signal sampling frequency in Hz.

[0091] According to the effective frequency domain subband range [k l ,k p ], for the frequency domain data matrix X f Perform interception (for the frequency domain data matrix X f Each row in the following operation is performed: If the element index k satisfies: k l <k<k p , retain the element, otherwise delete it, thus completing the truncation), the frequency domain data matrix after truncation is recorded as

[0092]

[0093] It should be noted that steps S20 to S30 in the present invention greatly improve the signal-to-noise ratio of the received signal, effectively reduce the impact of noise on the target positioning accuracy, and help improve the final positioning performance.

[0094] Step S40, selecting an initial value of the surface wave propagation velocity, an initial value of the scanning distance, and an initial value of the scanning angle, and sequentially calculating the distance from the scanning point to each sensor of the array, the beamformer weighting matrix, and the beamformer output power.

[0095] Specifically, an initial value of the surface wave propagation velocity is selected, denoted as c=c1, wherein c represents the surface wave velocity, and c1 represents a given initial value of the surface wave propagation velocity, in units of m / s.

[0096] Select the initial value of the scanning distance and the initial value of the scanning angle, denoted as r=r1 and θ=θ1 respectively, where the scanning distance r represents the distance from the scanning point to the origin of the coordinate system, and the unit is m. The scanning angle θ represents the angle of the coordinate system y rotated clockwise to the scanning point, and the unit is degree. r1 and θ1 represent the given initial value of the scanning distance and the initial value of the scanning angle.

[0097] Calculate the distance from the scanning point to each sensor in the array:

[0098]

[0099] Among them, x i and i They represent the x-coordinate and y-coordinate of the i-th sensor in the coordinate system respectively.

[0100] Compute the beamformer weight matrix:

[0101]

[0102] Calculate the beamformer output power:

[0103]

[0104] in, represents the Hadamard product (Hadamard, Hadamard product is a matrix calculation operation commonly used in machine learning), the symbol * represents the conjugate operation of the matrix, the symbol H represents the conjugate transpose operation of the matrix, and the symbol tr represents the trace operation of the matrix.

[0105] It should be noted that the beamformer output power calculated by the present invention includes the power of all frequency components of the seismic surface wave signal, which greatly improves the processing gain of the system, thereby helping to improve the target positioning accuracy and target detection distance.

[0106] Step S50: repeatedly select different scanning distances and scanning angles, repeatedly calculate the output power of the beamformer at all scanning distances and scanning angles, and form a spatial power scanning diagram.

[0107] Specifically, different scanning distances and scanning angles are repeatedly selected, denoted as r = ri and θ = θ i , by repeatedly calculating the distance from the scanning point to each sensor in the array, the beamformer weighting matrix, and the beamformer output power, the beamformer output power at all scanning distances and scanning angles can be obtained, and a spatial power scanning diagram can be formed.

[0108] The value ranges of the scanning distance and the scanning angle can be determined according to actual conditions.

[0109] Step S60: Search the spatial power scan diagram to obtain the maximum power point in the spatial power scan diagram, and the scanning distance and scanning angle corresponding to the maximum power point.

[0110] Specifically, the spatial power scan diagram obtained in step S50 of the present invention is searched to find the maximum power point in the spatial power scan diagram, as well as the scanning distance and scanning angle corresponding to the maximum power point.

[0111] Step S70: repeatedly select different surface wave propagation velocities to obtain the maximum power point under all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point, to form a data processing result matrix.

[0112] Specifically, different surface wave propagation velocities are repeatedly selected, denoted as c = c i , repeatedly calculate to obtain the maximum power point at all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point.

[0113] The above results are saved in the data processing result matrix R. The data processing result matrix R is:

[0114]

[0115] Wherein, P1 represents the maximum power obtained when the surface wave propagation velocity c1 is selected, r1 and θ1 represent the scanning distance and scanning angle corresponding to the maximum power point when the surface wave propagation velocity c1 is selected; P2 represents the maximum power obtained when the surface wave propagation velocity c2 is selected, r2 and θ2 represent the scanning distance and scanning angle corresponding to the maximum power point when the surface wave propagation velocity c2 is selected; and so on, P d It means that when the surface wave propagation velocity c is selected d The maximum power obtained when d and θ d They represent the surface wave propagation velocity c when d The scanning distance and scanning angle corresponding to the maximum power point.

[0116] Step S80: Compare and analyze the data in the data processing result matrix to obtain the estimated value of the surface wave velocity and the coordinate value of the ground vibration source target in the coordinate system.

[0117] Specifically, the first column of the data processing result matrix R is compared, and the row number of the maximum value in the first column of data is determined, which is recorded as g. Finally, the c in the gth row of the data processing result matrix R is g As the surface wave velocity estimate, according to the data processing result matrix R in the g-th row, g and θ g Calculate the x-coordinate value and y-coordinate value of the ground vibration source target in the coordinate system, that is:

[0118] x=r g sinθ g , x = r g cosθ g .

[0119] The present invention can realize accurate positioning of the ground vibration source without relying on prior knowledge of the surface wave velocity, and can also provide an estimated value of the surface wave velocity.

[0120] like Figure 2 As shown in the figure, the method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming specifically includes: (1) obtaining a time domain data matrix; (2) calculating a frequency domain data matrix based on an FFT algorithm; (3) calculating an effective frequency domain subband range; (4) intercepting the frequency domain data matrix; (5) selecting an initial value of the surface wave propagation velocity; (6) selecting an initial value of the scanning distance and an initial value of the scanning angle; (7) calculating the distance from the scanning point to each sensor of the array; (8) calculating a beamformer weighting matrix; (9) calculating the output power of the beamformer; (10) repeatedly selecting different scanning distances and scanning angles, and repeatedly executing steps (7) to (9) of the present invention to form a spatial power scanning diagram; (11) searching the spatial power scanning diagram; (12) repeatedly selecting different surface wave propagation velocities, and repeatedly executing steps (6) to (11) of the present invention to form a data processing result matrix; (13) completing target positioning and surface wave velocity estimation.

[0121] Furthermore, if Figure 3 As shown, based on the above-mentioned unknown wave velocity surface source positioning method based on broadband focused beamforming, the present invention also provides an unknown wave velocity surface source positioning system based on broadband focused beamforming, wherein the unknown wave velocity surface source positioning system based on broadband focused beamforming includes:

[0122] The signal acquisition module 51 is used to collect the received signals of all sensors in the array and construct a time domain data matrix;

[0123] A time domain calculation module 52, used for calculating the time domain data matrix based on a fast Fourier transform algorithm to obtain a frequency domain data matrix;

[0124] A frequency domain interception module 53, used to calculate the effective frequency domain sub-band range according to the existing geological exploration data, and intercept the frequency domain data matrix according to the effective frequency domain sub-band range;

[0125] A parameter calculation module 54 is used to select an initial value of the surface wave propagation velocity, an initial value of the scanning distance, and an initial value of the scanning angle, and to sequentially calculate the distance from the scanning point to each sensor of the array, the beamformer weighting matrix, and the beamformer output power;

[0126] A spatial power scan diagram forming module 55 is used to repeatedly select different scanning distances and scanning angles, repeatedly calculate the beamformer output power at all scanning distances and scanning angles, and form a spatial power scan diagram;

[0127] A spatial power scan map search module 56 is used to search the spatial power scan map to obtain the maximum power point in the spatial power scan map, and the scanning distance and scanning angle corresponding to the maximum power point;

[0128] The data processing result matrix forming module 57 is used to repeatedly select different surface wave propagation velocities to obtain the maximum power point under all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point, to form a data processing result matrix;

[0129] The coordinate calculation module 58 is used to compare and analyze the data in the data processing result matrix to obtain the estimated value of the surface wave velocity and the coordinate value of the ground vibration source target in the coordinate system.

[0130] Furthermore, if Figure 4 As shown, based on the above-mentioned method and system for locating surface earthquake sources with unknown wave velocity based on broadband focused beamforming, the present invention also provides a terminal accordingly, and the terminal includes a processor 10, a memory 20 and a display 30. Figure 4 Only some components of the terminal are shown, but it should be understood that it is not required to implement all of the components shown, and more or fewer components may be implemented instead.

[0131] In some embodiments, the memory 20 may be an internal storage unit of the terminal, such as a hard disk or memory of the terminal. In other embodiments, the memory 20 may also be an external storage device of the terminal, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the terminal. Further, the memory 20 may also include both an internal storage unit of the terminal and an external storage device. The memory 20 is used to store application software and various types of data installed in the terminal, such as the program code of the installation terminal, etc. The memory 20 may also be used to temporarily store data that has been output or is to be output. In one embodiment, the memory 20 stores an unknown wave velocity surface source positioning program 40 based on broadband focused beamforming, and the unknown wave velocity surface source positioning program 40 based on broadband focused beamforming can be executed by the processor 10, thereby realizing the unknown wave velocity surface source positioning method based on broadband focused beamforming in the present application.

[0132] In some embodiments, the processor 10 may be a central processing unit (CPU), a microprocessor or other data processing chip, used to run the program code or process data stored in the memory 20, such as executing the unknown wave velocity surface source locating method based on broadband focused beamforming.

[0133] In some embodiments, the display 30 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an OLED (Organic Light-Emitting Diode) touch device, etc. The display 30 is used to display information on the terminal and to display a visual user interface. The components 10-30 of the terminal communicate with each other via a system bus.

[0134] In one embodiment, when the processor 10 executes the unknown wave velocity surface earthquake source locating program 40 based on broadband focused beamforming in the memory 20, the steps of the unknown wave velocity surface earthquake source locating method based on broadband focused beamforming are implemented.

[0135] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores an unknown wave velocity surface earthquake source locating program based on broadband focused beamforming, and when the unknown wave velocity surface earthquake source locating program based on broadband focused beamforming is executed by a processor, the steps of the unknown wave velocity surface earthquake source locating method based on broadband focused beamforming as described above are implemented.

[0136] In summary, the present invention collects and stores received signals from all sensors in the array, and constructs a time domain data matrix; then, the time domain data matrix is ​​calculated based on the FFT algorithm to obtain a frequency domain data matrix; then, the effective frequency domain sub-band range is calculated according to the existing geological exploration data, and the frequency domain data matrix is ​​intercepted according to the effective frequency domain sub-band range; then, the initial value of the surface wave propagation velocity, the initial value of the scanning distance, and the initial value of the scanning angle are selected, and the distance from the scanning point to each sensor in the array, the beamformer weighting matrix, and the beamformer output power are calculated in turn; then, different scanning distances and scanning angles are repeatedly selected, and all scanning distances and scanning angles are repeatedly calculated. The beamformer output power at the angle is calculated to form a spatial power scan diagram; then, the spatial power scan diagram is searched to find the maximum power point in the spatial power scan diagram, as well as the scanning distance and scanning angle corresponding to the maximum power point; then, different surface wave propagation velocities are repeatedly selected, and the above steps are repeated to obtain the maximum power point under all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point, and the above results are saved in the data processing result matrix; finally, the data in the data processing result matrix are compared and analyzed to give the estimated value of the surface wave velocity, the x-coordinate value and the y-coordinate value of the ground vibration source target in the coordinate system.

[0137] Beneficial effects of the present invention: Compared with the existing ground vibration source positioning method, the method of the present invention can achieve accurate positioning of the ground vibration source without relying on prior knowledge of surface wave velocity, and can also provide an estimated value of the surface wave velocity. In addition, thanks to the higher processing gain of the method of the present invention, the method of the present invention can achieve ground vibration source positioning with a lower signal-to-noise ratio.

[0138] 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 device 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 device. 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 device including the element.

[0139] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for locating unknown wave velocity surface earthquake sources based on broadband focused beamforming, characterized in that: The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming comprises: Collect the received signals of all sensors in the array and construct a time domain data matrix; Calculating the time domain data matrix based on a fast Fourier transform algorithm to obtain a frequency domain data matrix; Calculating an effective frequency domain sub-band range according to existing geological exploration data, and intercepting the frequency domain data matrix according to the effective frequency domain sub-band range; Selecting the initial values ​​of the surface wave propagation velocity, the scanning distance and the scanning angle, and calculating the distance from the scanning point to each sensor of the array, the beamformer weighting matrix and the beamformer output power in turn; Repeatedly select different scanning distances and scanning angles, repeatedly calculate the output power of the beamformer at all scanning distances and scanning angles, and form a spatial power scanning diagram; Searching the spatial power scan graph to obtain a maximum power point in the spatial power scan graph, and a scan distance and a scan angle corresponding to the maximum power point; Repeatedly select different surface wave propagation velocities to obtain the maximum power point under all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point, to form a data processing result matrix; The data in the data processing result matrix are compared and analyzed to obtain the estimated value of the surface wave velocity and the coordinate value of the ground vibration source target in the coordinate system.

2. The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming according to claim 1, characterized in that: The receiving signals of all sensors in the acquisition array and constructing a time domain data matrix specifically include: Collect and store the received signals of all sensors in the array, and construct the time domain data matrix X as: Where N represents the number of array elements, L represents the data length of the signal received by a single sensor array element, and x i (j) represents the received data of the i-th array element at the j-th time, and i represents one of N.

3. The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming according to claim 2, characterized in that: The array is formed by arranging a plurality of vibration sensors according to a certain spatial pattern; the vibration sensor is a velocity sensor used to measure the vibration velocity of a medium.

4. The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming according to claim 2, characterized in that: The step of calculating the time domain data matrix based on the fast Fourier transform algorithm to obtain the frequency domain data matrix specifically includes: Based on the fast Fourier transform algorithm, each row of the time domain data matrix X is subjected to a discrete Fourier transform of L points: Among them, X m (k) represents the FFT transform form corresponding to each element in the time domain data matrix X, l represents the index number after discrete sampling of the time domain signal; k represents the frequency domain subband number, and the value range is k=0,1,…L-1; m represents the sensor array element number, and the value range is k=0,1,…N-1; Using all discrete Fourier transform results, construct the frequency domain data matrix X f :

5. The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming according to claim 4, characterized in that: The calculating of the effective frequency domain sub-band range according to the existing geological exploration data and intercepting the frequency domain data matrix according to the effective frequency domain sub-band range specifically includes: According to the existing geological exploration data, the frequency range of the seismic surface wave signal is determined and recorded as [f l ,f p ], where f l Represents the lower frequency limit of the seismic surface wave signal, in Hz; f p Represents the upper frequency limit of the seismic surface wave signal, in Hz; The frequency range of the seismic surface wave signal is converted into an effective frequency domain subband range [k l ,k p ], the specific conversion is as follows: The symbol [·] represents rounding operation, f s Represents the signal sampling frequency in Hz; According to the effective frequency domain subband range [k l ,k p ], for the frequency domain data matrix X f The frequency domain data matrix after interception is recorded as 6. The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming according to claim 5, characterized in that: The selecting of the initial value of the surface wave propagation velocity, the initial value of the scanning distance and the initial value of the scanning angle, and sequentially calculating the distance from the scanning point to each sensor of the array, the beamformer weighting matrix and the beamformer output power specifically includes: Select the initial value of the surface wave propagation velocity, denoted as c=c1, where c represents the surface wave velocity, and c1 represents the given initial value of the surface wave propagation velocity, in units of m / s; Select the initial value of the scanning distance and the initial value of the scanning angle, which are denoted as r=r1 and θ=θ1 respectively, where the scanning distance r represents the distance from the scanning point to the origin of the coordinate system, in meters, and the scanning angle θ represents the angle from the coordinate system y to the scanning point clockwise, in degrees, and r1 and θ1 represent the given initial values ​​of the scanning distance and scanning angle; Calculate the distance from the scanning point to each sensor in the array: Among them, x i and i Respectively represent the x-coordinate and y-coordinate of the i-th sensor in the coordinate system; Compute the beamformer weight matrix: Calculate the beamformer output power: in, represents the Hadamard product, the symbol * represents the conjugate operation of the matrix, the symbol H represents the conjugate transpose operation of the matrix, and the symbol tr represents the trace operation of the matrix.

7. The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming according to claim 6, characterized in that: The repeatedly selecting different scanning distances and scanning angles, repeatedly calculating the beamformer output power at all scanning distances and scanning angles, and forming a spatial power scanning diagram specifically includes: Repeatedly select different scanning distances and scanning angles, denoted as r = r i and θ = θ i , repeatedly calculating the distance from the scanning point to each sensor in the array, the beamformer weighting matrix, and the beamformer output power; The output power of the beamformer at all scanning distances and scanning angles is obtained according to the calculation results, and a spatial power scanning diagram is formed.

8. The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming according to claim 7, characterized in that: The method repeatedly selects different surface wave propagation velocities to obtain the maximum power point under all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point, to form a data processing result matrix, which specifically includes: Repeatedly select different surface wave propagation velocities, denoted as c = c i , repeatedly calculate to obtain the maximum power point at all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point; The results are saved in the data processing result matrix R. The data processing result matrix R is: Wherein, P1 represents the maximum power obtained when the surface wave propagation velocity c1 is selected, r1 and θ1 represent the scanning distance and scanning angle corresponding to the maximum power point when the surface wave propagation velocity c1 is selected; P2 represents the maximum power obtained when the surface wave propagation velocity c2 is selected, r2 and θ2 represent the scanning distance and scanning angle corresponding to the maximum power point when the surface wave propagation velocity c2 is selected; P d It means that when the surface wave propagation velocity c is selected d The maximum power obtained when d and θ d They represent the surface wave propagation velocity c when d The scanning distance and scanning angle corresponding to the maximum power point.

9. The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming according to claim 8, characterized in that: The step of comparing and analyzing the data in the data processing result matrix to obtain the estimated value of the surface wave velocity and the coordinate value of the ground vibration source target in the coordinate system specifically includes: Compare the first column of the data processing result matrix R and determine the row number where the maximum value in the first column of data is located, denoted as g. Finally, c in the gth row of the data processing result matrix R is g As the surface wave velocity estimate, according to the data processing result matrix R in the g-th row, g and θ g Calculate the x-coordinate value and y-coordinate value of the ground vibration source target in the coordinate system, that is: x=r g sinθ g ,x=r g cosθ g 。 10. The method for locating an unknown wave velocity surface earthquake source based on broadband focused beamforming according to claim 6, characterized in that: in, The calculated beamformer output power contains the power of all frequency components of the seismic surface wave signal.

11. A surface earthquake source location system for unknown wave velocity based on broadband focused beamforming, characterized in that: The unknown wave velocity surface source positioning system based on broadband focused beamforming comprises: The signal acquisition module is used to collect the received signals of all sensors in the array and construct a time domain data matrix; A time domain calculation module, used for calculating the time domain data matrix based on a fast Fourier transform algorithm to obtain a frequency domain data matrix; A frequency domain interception module, used to calculate the effective frequency domain sub-band range according to the existing geological exploration data, and intercept the frequency domain data matrix according to the effective frequency domain sub-band range; A parameter calculation module is used to select an initial value of the surface wave propagation velocity, an initial value of the scanning distance, and an initial value of the scanning angle, and to sequentially calculate the distance from the scanning point to each sensor of the array, a beamformer weighting matrix, and a beamformer output power; A spatial power scan diagram forming module, used for repeatedly selecting different scanning distances and scanning angles, repeatedly calculating the output power of the beamformer at all scanning distances and scanning angles, and forming a spatial power scan diagram; A spatial power scanning diagram search module, used to search the spatial power scanning diagram to obtain the maximum power point in the spatial power scanning diagram, and the scanning distance and scanning angle corresponding to the maximum power point; The data processing result matrix forming module is used to repeatedly select different surface wave propagation velocities to obtain the maximum power point under all surface wave propagation velocities, as well as the scanning distance and scanning angle corresponding to the maximum power point, to form a data processing result matrix; The coordinate calculation module is used to compare and analyze the data in the data processing result matrix to obtain the estimated value of the surface wave velocity and the coordinate value of the ground vibration source target in the coordinate system.

12. A terminal, characterized in that: The terminal includes: a memory, a processor, and an unknown wave velocity surface earthquake source locating program based on broadband focused beamforming stored in the memory and executable on the processor. When the unknown wave velocity surface earthquake source locating program based on broadband focused beamforming is executed by the processor, the steps of the unknown wave velocity surface earthquake source locating method based on broadband focused beamforming as described in any one of claims 1 to 10 are implemented.

13. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores an unknown wave velocity surface earthquake source locating program based on broadband focused beamforming, and when the unknown wave velocity surface earthquake source locating program based on broadband focused beamforming is executed by a processor, the steps of the unknown wave velocity surface earthquake source locating method based on broadband focused beamforming as described in any one of claims 1 to 10 are implemented.

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