Method, system and computing device for joint estimation of array shape correction and noise source localization during linear array rotation

Abstract

The application discloses a kind of line array rotary time array shape correction and noise source positioning joint estimation method, system and computing device, and the joint estimation method includes the following steps: preliminary estimation line array element position;Preliminary positioning sound source position;Calculate the delay time of each array element in line array relative to the 1st array element, and calculate the steering vector and array flow pattern matrix;Establish target cost function and constraint condition to optimize and solve the correction amount of each array element in line array;According to the array element position under preliminary estimation array shape and the correction amount of each array element in line array, calculate the corrected line array element position;Based on second-order polynomial fitting method, curve fitting is carried out to each array element position, and the line array element position after curve fitting is obtained;Based on the new array element position, the array flow pattern matrix is corrected, and the sound source position is positioned again under the new array flow pattern using minimum variance distortionless response algorithm.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of target positioning, and particularly relates to a method, system and computing device for joint estimation of array shape correction and noise source positioning during rotation of a towed line array, wherein the joint estimation method can realize joint estimation of array shape correction and noise source positioning, and the positioning accuracy of the noise source under the corrected array shape is more accurate and no virtual source is generated due to excessively high sidelobes. BACKGROUND

[0002] A towed line array sonar (i.e., a towed line array sonar) has good underwater detection performance and is relatively easy to operate. When the towed line array sonar is used for target direction finding, the array shape is usually assumed to be a straight line. During the search, positioning, tracking and other processes of the target, the user usually needs to maneuver the platform to obtain detection advantages, such as obtaining a longer detection distance, a higher search rate, more accurate target positioning and a more favorable evading array position and the like. These maneuvers of the towed line array platform will inevitably affect the base array shape of the towed line array sonar, causing distortion and deviating from the assumed straight line shape. The mismatch between the actual array shape of the towed line array sonar and the theoretical assumption due to the platform maneuvering will seriously affect the target detection capability and direction finding accuracy of the sonar, making it difficult for the towed line array platform to maintain stable tracking and high-precision positioning of the underwater target, and greatly reducing the use efficiency.

[0003] So far, the towed line array shape estimation and calibration techniques can be divided into the following types: (1) using non-acoustic sensor information to estimate the array shape: a posture sensor is installed on the acoustic section of the towed line array, and the posture information such as yaw, pitch and roll at different positions of the base array is used to estimate the base array shape by a polynomial fitting method. The defect of this method is that the measurement accuracy of the posture sensor is required to be very high, and the required data rate is large, which is currently difficult to meet the actual engineering requirements. (2) a mechanical modeling is performed on the force state of the towed line array, and the array shape of the towed line array is estimated by solving the mechanical equation. This method requires real-time and accurate understanding of the force state of each section of the towed array, and the required calculation amount is large, and it is currently difficult to achieve real-time prediction of the array shape of the towed line array during complex maneuvers of the ship, and only a small amount of attempts have been made in the aspect of towed body posture estimation. (3) the array shape of the towed line array is estimated according to the empirical equation of the cable array force, i.e., the Paidoussis equation. This kind of method considers the force state of the cable array under the action of seawater medium, and solves the two-dimensional position transient distribution of the towed line array by solving the motion control equation of the towed line array. The defect of this method is that the model constants in the Paidoussis equation under different motion states of the towed line array need to be accurately mastered, and the solving calculation is complex, and it is currently difficult to achieve real-time and accurate array shape estimation in actual engineering application. It can be seen that the above three methods are weak in operability and are not conducive to the estimation and calibration of the towed line array shape. SUMMARY

[0004] To address the above technical issues, the present invention proposes a joint estimation method for formation correction and noise source positioning during towed array rotation. Based on the preliminary estimation of the towed array element positions using traditional dynamic methods, the method uses the output energy of the beamformer to more accurately estimate the towed array formation. This method does not rely on prior knowledge of the formation, can adapt to changes in the underwater acoustic environment, and can achieve joint estimation of formation correction and noise sources. The noise source positioning accuracy is more accurate under the corrected formation, and virtual sources are not generated due to excessively high sidelobes. The joint estimation method includes the following steps:

[0005] S1, preliminarily estimate the position of the towed array elements based on the dynamic method;

[0006] S2, preliminarily locates the sound source position based on the minimum variance distortion-free response focused beamforming algorithm;

[0007] S3, calculating the delay time of each array element in the towed array relative to the first array element based on the estimated sound source position, and calculating the steering vector and array flow matrix;

[0008] S4, based on the calculated array flow matrix, establish a target cost function and constraint conditions to optimize and solve the correction amount of each array element in the towed array;

[0009] S5, calculating the corrected positions of the elements of the towed array according to the preliminary estimated positions of the elements in the array and the correction values ​​of the elements of the towed array;

[0010] S6, performing curve fitting on each array element position based on a second-order polynomial fitting method to obtain the array element position of the towline array after curve fitting;

[0011] In S7, the array flow matrix is ​​modified based on the new array element positions, and the minimum variance distortionless response focused beamforming algorithm is used again to locate the sound source position under the new array flow pattern.

[0012] In step S1, the position of the array elements is preliminarily estimated according to the dynamic method. First, a group of motion control equations describing the real-time changes of the towed array must be established, and the boundary conditions for solving this group of motion control equations must be determined in combination with the characteristics of the towed array. The partial differential equations are discretized into a group of differential equations by differential analysis, and then the numerical solution is solved using the numerical calculation method to obtain the preliminary estimated position of the towed array during rotation. After the calculation, each array element The initial estimated coordinate vector on the axis is ; Each array element The initial estimated coordinate vector on the axis is .

[0013] In step S2, the sound source position is preliminarily located based on the minimum variance distortionless response focused beamforming algorithm, and the calculation formula is as follows: wherein is the array steering vector; is the array covariance matrix; represents the inverse, according to the peak value of the array spatial spectrum function, the estimated position of the sound source ; , represent the two-dimensional coordinate values of the th sound source on the axis and the axis respectively, represents the index of the sound source; represents the spatial spectrum.

[0014] In the step S3, the delay time of each element in the towed line array relative to the first element is calculated according to the estimated position of the sound source, and the array flow pattern matrix and the steering vector are calculated, wherein the delay time of each element in the towed line array relative to the first element calculated according to the estimated position of the sound source is: wherein , represent the two-dimensional coordinate values of the th sound source on the axis and the axis respectively; represents the distance between the th element and the th sound source; represents the sound velocity; represents the distance between the reference element and the th sound source. , represent the two-dimensional coordinate values of the th element on the axis and the axis respectively; , represent the two-dimensional coordinate values of the first element on the axis and the axis respectively, and the first element is taken as the reference element, and the calculation formula of the steering vector is: wherein T represents the transpose, the angular frequency is , is the frequency of the noise source, represents the total number of elements, and on this basis, the array flow pattern matrix of dimensions is calculated, and the formula is: wherein each column of the array flow pattern matrix is the steering vector corresponding to the th sound source; is the total number of incoherent sound sources.

[0015] The step S4, based on the calculated array flow pattern matrix, establishes a target cost function and constraint conditions to optimize the solution of the correction amount of each array element of the towed array, and the target cost function is The formula is: ,

[0016] The constraint condition is: , , Where the array flow pattern matrix when the towed array rotates is ; is an dimensional array flow pattern matrix; , is the two-dimensional coordinate correction amount of the array element position after array shape correction and the array element position under the preliminary estimated array shape on the axis, axis; , is the two-dimensional coordinate of the array shape on the axis, axis. When the array estimated array shape is consistent with the actual array shape, the space of the array flow pattern matrix is approximately parallel to the space of the array received signal matrix , represents the Euclidean norm, represents the index of the array element, represents the total number of array elements. represents the maximum value of the array element position correction amount, , represents the correction amount of the th array element.

[0017] The step S5, according to the array element position under the preliminary estimated array shape and the correction amount of each array element of the towed array, calculates the corrected array element position of the towed array, and the array element position calculation formula on the axis, axis is respectively: , Where , is the two-dimensional coordinate correction amount of the array element position after array shape correction and the array element position under the preliminary estimated array shape on the axis, axis; , is the two-dimensional coordinate of the array shape on the axis, axis; , is the array element position after array shape correction.

[0018] In step S6, curve fitting is performed on each element position based on a second-order polynomial fitting method to obtain the element positions of the towline array after curve fitting. The solution formulas for the second-order coefficient, first-order coefficient, and constant term of the second-order polynomial are as follows: ,in For the first Array elements in The coordinates on the axis, is the position vector of the drag array The elements, For the first Array elements in The coordinates on the axis, is the position vector of the drag array The elements, is the total number of array elements in the towline array, Indicates the index of the array element.

[0019] In step S7, the array flow matrix is ​​modified based on the new array element positions, and the minimum variance distortionless response focused beamforming algorithm is used again to locate the sound source position under the new array flow pattern. The calculation formula is: ,in is the modified array steering vector, which is a single column in the array flow matrix; is the array covariance matrix; Indicates inversion. According to the peak value of the array spatial spectrum function, the estimated position of the sound source can be estimated; Represents the spatial spectrum.

[0020] According to another aspect of the present invention, the present invention further provides a system for jointly estimating formation correction and noise source location during towed array rotation, for implementing formation correction and noise source joint estimation, wherein the joint estimation system comprises:

[0021] A preliminary estimation unit, used for preliminarily estimating the position of the towed array element according to a dynamic method;

[0022] A preliminary positioning unit, used for preliminarily locating the sound source position based on a minimum variance distortionless response focused beamforming algorithm;

[0023] A first calculation unit is used to calculate the delay time of each array element in the towed array relative to the first array element according to the estimated sound source position, and calculate the steering vector and the array flow matrix;

[0024] The second calculation unit is used to establish a target cost function and constraint conditions based on the calculated array flow matrix to optimize the correction amount of each array element in the towed array;

[0025] a third calculation unit, configured to calculate the positions of the elements of the modified line array according to the positions of the elements in the preliminary estimated array shape and the correction amounts of the elements of the line array;

[0026] a fitting unit, configured to perform curve fitting on the positions of the elements based on a second-order polynomial fitting method to obtain the positions of the elements of the line array after curve fitting;

[0027] a sound source positioning unit, configured to modify the array flow matrix based on the new positions of the elements, and position the sound source again under the new array flow by using the minimum variance distortionless response focused beam forming algorithm.

[0028] According to another aspect of the present application, the present application further provides a computing device comprising a processor and a memory, wherein computer program instructions are stored in the memory, and the computer program instructions make the processor execute the joint estimation method for array shape correction and noise source positioning during line array rotation when the computer program instructions are executed in the processor, wherein the joint estimation method comprises the following steps:

[0029] S1, initially estimating the positions of the elements of the line array according to a dynamic method;

[0030] S2, initially positioning the sound source based on the minimum variance distortionless response focused beam forming algorithm;

[0031] S3, calculating the delay time of each element of the line array relative to the first element and the steering vector and the array flow matrix according to the estimated position of the sound source;

[0032] S4, establishing a target cost function and a constraint condition based on the calculated array flow matrix to optimize and solve the correction amounts of the elements of the line array;

[0033] S5, calculating the positions of the elements of the modified line array according to the positions of the elements in the preliminary estimated array shape and the correction amounts of the elements of the line array;

[0034] S6, performing curve fitting on the positions of the elements based on a second-order polynomial fitting method to obtain the positions of the elements of the line array after curve fitting;

[0035] S7, modifying the array flow matrix based on the new positions of the elements, and positioning the sound source again under the new array flow by using the minimum variance distortionless response focused beam forming algorithm.

[0036] Compared with existing technologies, the present invention has at least the following advantages: the joint estimation method of the present invention enables formation correction and joint noise source estimation. Furthermore, the noise source positioning accuracy is more accurate under the corrected formation, and virtual sources are not generated due to excessively high sidelobes. Using the joint estimation method of the present invention, when the towed array is used as a range sensor for a towed platform, it can maintain high-precision positioning and stable tracking of underwater targets, enabling visualization of the underwater environment and satisfying the towed platform's search requirements for underwater targets. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the processing flow of the method for jointly estimating the formation correction and noise source positioning when the towed array rotates according to the present invention.

[0038] Figure 2 These are the formation estimation and formation correction results during the rotation of the towed array of the present invention.

[0039] Figure 3 This is the minimum variance distortion-free response focused beamforming result based on the preliminary estimated array under a single sound source.

[0040] Figure 4 This is the minimum variance distortion-free response focused beamforming result based on array correction under a single sound source.

[0041] Figure 5 This is the minimum variance distortion-free response focused beamforming result based on the preliminary estimated array under dual sound sources.

[0042] Figure 6 This is the minimum variance distortion-free response focused beamforming result based on array correction under dual sound sources.

[0043] Figure 7 This is a block diagram of the combined estimation system for array correction and noise source positioning during towed array rotation according to the present invention.

[0044] Figure 8 is a block diagram of a computing device of the present invention. DETAILED DESCRIPTION

[0045] Reference Attachment Figures 1 to 6 In the following description, a method for jointly estimating the formation correction and noise source positioning of a towed array during its rotation according to a preferred embodiment of the present invention will be disclosed and explained. In this method, the output energy of the beamformer is used to more accurately estimate the formation of the towed array based on the preliminary estimation of the position of the towed array elements by the traditional dynamic method. This method does not need to rely on prior knowledge of the formation, can adapt to changes in the underwater acoustic environment, and can realize joint estimation of the formation correction and noise source. In addition, the noise source positioning accuracy is more accurate under the corrected formation, and no virtual source is generated due to excessively high sidelobes.

[0046] Specifically, the joint estimation method of the present invention includes the following steps: S1, preliminarily estimating the position of the towed array element according to the dynamic method; S2, preliminarily locating the sound source position based on the minimum variance distortionless response focused beamforming algorithm; S3, calculating the delay time of each element in the towed array relative to the first element according to the estimated sound source position, and calculating the steering vector and the array flow matrix; S4, based on the calculated array flow matrix, establishing the target cost function and constraint conditions to optimize the correction amount of each element in the towed array; S5, calculating the corrected towed array element position based on the preliminary estimated array element position and the correction amount of each element of the towed array; S6, performing curve fitting on each element position based on the second-order polynomial fitting method to obtain the towed array element position after curve fitting; S7, correcting the array flow matrix based on the new element position, and again using the minimum variance distortionless response focused beamforming algorithm to locate the sound source position under the new array flow. Through the above steps, the joint estimation method of the present invention can use the output energy of the beamformer to more accurately estimate the towed array formation based on the preliminary estimation of the towed array elements using the traditional dynamic method, so as to realize formation correction and joint estimation of noise sources. The noise source positioning accuracy is more accurate under the corrected formation, and no virtual source is generated due to excessively high sidelobes.

[0047] More specifically, in step S1, the position of the array elements is preliminarily estimated according to the dynamic method. First, a group of motion control equations describing the real-time changes of the towed array is established, and the boundary conditions for solving the group of motion control equations are determined in combination with the characteristics of the towed array. Secondly, the partial differential equations are discretized into a group of differential equations through differential analysis, and then the numerical calculation method is used to solve the numerical solution to obtain the preliminary estimated position of the towed array during rotation. After the calculation, each array element The initial estimated coordinate vector on the axis is ; Each array element The initial estimated coordinate vector on the axis is .

[0048] In step S2, the sound source position is preliminarily located based on the minimum variance distortionless response focused beamforming algorithm, and the calculation formula is as follows: ,in, is the array steering vector, is the array covariance matrix, Indicates inversion. According to the peak value of the array spatial spectrum function, the estimated position of the sound source can be estimated , 、 Respectively represent The sound source is axis, The two-dimensional coordinate values ​​on the axis, Indicates the index of the sound source, Represents the spatial spectrum. In the calculation formula Medium, superscript is the abbreviation of Hermitian, which means conjugate transpose, that is, Steering vector for array Perform transposition.

[0049] In step S3, the delay time of each array element in the towed array relative to the first array element is calculated based on the estimated sound source position, and the steering vector and array flow matrix are calculated. Here, the delay time of each array element in the towed array relative to the first array element is calculated based on the estimated sound source position as follows: ,in 、 Respectively represent The sound source is axis, Two-dimensional coordinate values ​​on the axis; Indicates the Element to The distance between the sound sources, represents the speed of sound, Indicates the reference element to the The distance between the sound sources, 、 Respectively represent Array elements in axis, The two-dimensional coordinate values ​​on the axis, 、 Respectively represent the first array element in axis, The two-dimensional coordinate value on the axis, the first array element is used as the reference array element;

[0050] The calculation formula of the steering vector is: , where T represents the transpose and the angular frequency is , is the frequency of the noise source. Represents the total number of array elements. On this basis, calculate The calculation formula of the array flow matrix is: , where each column of the array flow matrix corresponds to Steering vector of a sound source ; is the total number of incoherent sound sources.

[0051] In step S4, based on the calculated array flow matrix, a target cost function and constraint conditions are established to optimize the correction value of each element of the towed array. The target cost function is The formula is: , the constraints are: , , wherein the array flow pattern matrix is , is a matrix of the array flow pattern; , is the two-dimensional coordinate correction of the array element position in the axis, axis, , is the two-dimensional coordinate of the array shape in the axis, axis, the space of the array flow pattern matrix is approximately parallel to the space of the array receiving signal matrix denotes the Euclidean norm, denotes the index of the array element, denotes the total number of array elements, denotes the maximum value of the array element position correction, , denotes the correction of the th array element. denotes the partial derivative of , denotes the partial derivative of .

[0052] In the step S5, the corrected array element position of the streamer array is calculated according to the array element position in the preliminary estimated array shape and the correction of each array element of the streamer array, wherein the array element position calculation formula in the axis, axis is respectively: , wherein , is the two-dimensional coordinate correction of the array element position in the axis, axis, , is the two-dimensional coordinate of the array shape in the axis, axis, , is the array element position after the array shape correction.

[0053] In the step S6, the curve fitting of each array element position is performed based on the second-order polynomial fitting method to obtain the array element position after the curve fitting, wherein the solving formula of the second-order coefficient, the first-order coefficient and the constant term of the second-order polynomial is as follows: ,in For the first Array elements in The coordinates on the axis, is the position vector of the drag array The elements, For the first Array elements in The coordinates on the axis, is the position vector of the drag array The elements, is the total number of array elements in the towline array, Indicates the index of the array element.

[0054] In step S7, the array flow matrix is ​​modified based on the new array element positions, and the minimum variance distortionless response algorithm is used again to locate the sound source position under the new array flow pattern. The calculation formula is: ,in, is the modified array steering vector, which is a separate column in the array flow matrix. is the array covariance matrix, Indicates the inversion. According to the peak value of the array spatial spectrum function, the estimated position of the sound source can be estimated. Represents the spatial spectrum.

[0055] A simulation experiment of joint estimation of array element position correction and noise source location during the rotation of the towed array was carried out to verify the feasibility of the joint estimation method of the present invention. Specifically, the diameter of the towed array is 0.066m, the density is 3.5kg / m, the normal drag coefficient is 1.8, and the Young's modulus is The towed array has 64 elements, an array spacing of 0.75m, and a seawater sound speed of 1500m / s. Based on dynamic methods, the towed array's formation during rotation can be estimated, providing a preliminary estimate of the formation. Figure 2 The solid line is the actual formation, the dashed line is the preliminary estimated formation, and the dotted line is the corrected formation obtained based on the joint estimation method of the present invention. Figure 1 It can be seen that compared with the initial estimated formation, the position deviation between the corrected formation and the actual formation is smaller.

[0056] Assuming a single sound source, the two-dimensional coordinate position of the sound source is (10, 50), the center frequency of the sound source is 1kHz, the array receiving signal-to-noise ratio is 10dB, and the background noise is Gaussian noise, the minimum variance distortion-free response focused beamforming results under the preliminary estimated formation and the corrected formation are calculated respectively, as shown below: Figure 3 and Figure 4The sound source positioning result based on near-field minimum variance distortionless response in the preliminary estimated array shape is (10, 50), (11, 46), and due to the mismatch of the array shape, the near-field minimum variance distortionless response focusing beam has a high sidelobe, which produces a virtual source with two-dimensional coordinates (11, 46). Figure 3 The sidelobe of the minimum variance distortionless response focusing beam shown in the figure is too high, and a virtual source with two-dimensional coordinates (11, 46) is produced, and after the array shape is corrected, Figure 4 the sound source positioning result based on near-field minimum variance distortionless response in the preliminary estimated array shape is (10, 50), (11, 46), and due to the mismatch of the array shape, the near-field minimum variance distortionless response focusing beam has a high sidelobe, which produces a virtual source with two-dimensional coordinates (11, 46). Figure 4 It can be known that, compared with the result after the preliminary estimated array shape, the positioning accuracy of the double noise sources based on the corrected array shape is higher.

[0057] It is assumed that the positions of the non-coherent double sound sources are (10, 50), (32, 46) respectively, the center frequency of the sound sources is 1 kHz, the array receiving signal-to-noise ratio is 15 dB, other parameters are unchanged, the minimum variance distortionless response focusing beam forming results in the preliminary estimated array shape and the corrected array shape are calculated respectively, as shown in Figs. Figure 5 and Figure 6 Under the preliminary estimated array shape, Figure 5 the sound source positioning result based on near-field minimum variance distortionless response in the preliminary estimated array shape is (10, 50), (11, 46), and due to the mismatch of the array shape, the near-field minimum variance distortionless response focusing beam has a high sidelobe, which produces a virtual source with two-dimensional coordinates (11, 46). Figure 6 the sound source positioning result based on near-field minimum variance distortionless response in the preliminary estimated array shape is (10, 50), (11, 46), and due to the mismatch of the array shape, the near-field minimum variance distortionless response focusing beam has a high sidelobe, which produces a virtual source with two-dimensional coordinates (11, 46). Figure 5 and Figure 6 It can be known that, compared with the result after the preliminary estimated array shape, the positioning accuracy of the double noise sources based on the corrected array shape is higher.

[0058] According to another aspect of the present application, reference is made to the accompanying drawings. Figure 7The application further provides a system 700 for jointly estimating array shape correction and noise source positioning during rotation of a towed line array, wherein the system 700 comprises a preliminary estimation unit 710, a preliminary positioning unit 720, a first calculation unit 730, a second calculation unit 740, a third calculation unit 750, a fitting unit 760 and a sound source positioning unit 770, which cooperate with each other to enable the system 700 to more accurately estimate the array shape of the towed line array by using the output energy of a beamformer on the basis of the preliminary estimation of the positions of the elements of the towed line array by a conventional dynamic method, so that the system 700 can adapt to changes in the underwater acoustic environment without relying on prior knowledge of the array shape, can realize joint estimation of array shape correction and noise source positioning, and has more accurate positioning precision of noise sources under the corrected array shape and does not produce virtual sources due to excessively high side lobes.

[0059] Specifically, the preliminary estimation unit 710 is configured to preliminarily estimate the positions of the elements of the towed line array according to a dynamic method. More specifically, according to the dynamic method, the preliminary estimation unit 710 first establishes a motion control equation set for describing real-time changes in the array shape of the towed line array, determines boundary conditions for solving the motion control equation set in combination with the characteristics of the towed line array, and then converts the partial differential equation set into a difference equation set by difference discretization, and then solves the numerical solution by using a numerical calculation method to obtain the preliminary estimation positions of the towed line array during rotation. After calculation, the preliminary estimation coordinate vector of each element of the towed line array on the x-axis is the preliminary estimation coordinate vector of each element of the towed line array on the y-axis is .

[0060] The preliminary positioning unit 720 is configured to preliminarily position the positions of sound sources based on a minimum variance distortionless response focused beamforming algorithm, and the calculation formula is as follows wherein, is an array steering vector, is an array covariance matrix, denotes inversion, and according to the peak value of the array spatial spectrum function, the estimated position of the sound source can be estimated , , denote the two-dimensional coordinate values of the i th sound source on the x-axis and the y-axis, respectively, denotes the index of the sound source, denotes spatial spectrum.

[0061] ​​​​​The first calculation unit 730 is configured to calculate the delay time of each array element in the line array relative to the first array element according to the estimated sound source position, and calculate the steering vector and the array flow pattern matrix, wherein the delay time of each array element in the line array relative to the first array element according to the estimated sound source position is , , respectively represent the two-dimensional coordinate values of the i th sound source on the x-axis and the y-axis; represents the distance between the i th array element and the i th sound source, represents the sound velocity, , , wherein T represents the transpose, the angular frequency is , and the frequency of the noise source. represents the total number of array elements, and on this basis, the array flow pattern matrix of M dimensions is calculated, and the calculation formula is , wherein each column of the array flow pattern matrix is the steering vector corresponding to the i th sound source ;

[0062] The second calculation unit 740 is configured to establish a target cost function and a constraint condition based on the calculated array flow pattern matrix, so as to solve the correction amount of each array element in the line array, and the formula of the target cost function is

[0063] The constraint condition is , , , wherein the array flow pattern matrix when the line array rotates is , is the array flow pattern matrix of M dimensions; ​​​​​​​​​​​​​​​​​​​​​The position of the array element after formation correction and the position of the array element under the initial estimation formation are axis, The two-dimensional coordinate correction on the axis, 、 For the formation axis, The two-dimensional coordinates on the axis, when the array estimated formation is consistent with the actual formation, the array flow matrix Space and array receiving signal matrix The space is approximately parallel, represents the Euclidean norm, Indicates the index of the array element, Represents the total number of array elements, Indicates the maximum value of the array element position correction, 、 Indicates the The correction amount of each array element.

[0064] The third calculation unit 750 is used to calculate the corrected position of the towed array element according to the initial estimated array element position and the correction value of each array element of the towed array, wherein axis, The calculation formulas for the array element positions on the axis are , ,in 、 The position of the array element after formation correction and the position of the array element under the initial estimation formation are axis, The two-dimensional coordinate correction on the axis, 、 For the formation axis, The two-dimensional coordinates on the axis, 、 is the position of the array element after formation correction.

[0065] The fitting unit 760 is used to perform curve fitting on each array element position based on the second-order polynomial fitting method to obtain the array element position of the towline array after curve fitting. The solution formula for the second-order coefficient, first-order coefficient, and constant term of the second-order polynomial is as follows: ,in For the first Array elements in The coordinates on the axis, is the position vector of the drag array The elements, For the first Array elements in The coordinates on the axis, is the position vector of the drag array The elements, is the total number of array elements in the towline array, Indicates the index of the array element.

[0066] The sound source localization unit 770 is used to modify the array flow matrix based on the new array element position, and to locate the sound source position again using the minimum variance distortionless response focused beamforming algorithm under the new array flow pattern. The calculation formula is: ,in is the modified array steering vector, which is a separate column in the array flow matrix. is the array covariance matrix, Indicates the inversion. According to the peak value of the array spatial spectrum function, the estimated position of the sound source can be estimated. Represents the spatial spectrum.

[0067] Reference Attachment Figure 8 According to another aspect of the present invention, the present invention further provides a computing device 800, wherein the computing device 800 includes a processor 810 and a memory 820, wherein computer program instructions are stored in the memory 820, and when the computer program instructions are executed in the processor 810, the processor 810 executes a joint estimation method for array correction and noise source positioning when the towed array rotates, wherein the joint estimation method includes the following steps: preliminarily estimating the position of the towed array element according to a dynamic method; preliminarily locating the sound source position based on a minimum variance distortionless response focused beamforming algorithm; calculating the delay time of each element in the towed array relative to the first element according to the estimated sound source position, and calculating the steering vector and the array flow matrix; establishing a target cost function and constraint conditions based on the calculated array flow matrix to optimize the towed array. The invention relates to a method for calculating the correction amount of each element in the array; calculating the corrected element positions of the towed array based on the element positions under the preliminary estimation of the array shape and the correction amount of each element of the towed array; performing curve fitting on each element position based on a second-order polynomial fitting method to obtain the element positions of the towed array after the curve fitting; correcting the array flow pattern matrix based on the new element positions, and again using the minimum variance distortionless response focusing beamforming algorithm to locate the sound source position under the new array flow pattern. In this way, the computing device 800 can use the output energy of the beamformer to more accurately estimate the towed array shape based on the preliminary estimation of the element positions of the towed array by the traditional dynamic method, thereby eliminating the need to rely on prior knowledge of the array shape, adapting to changes in the underwater acoustic environment, and realizing joint estimation of the array shape correction and noise source. In addition, the noise source positioning accuracy is more accurate under the corrected array shape, and no virtual source is generated due to excessively high sidelobes.

[0068] In an embodiment of the computing device 800 of the present application, the memory 820 can include one or more computer program products, which can include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory, for example, can include random access memory (RAM), cache memory, and / or the like. The non-volatile memory, for example, can include read-only memory (ROM), hard disk drives, solid-state drives, and / or the like. The computer-readable storage media can store one or more computer program instructions, which can be executed by the processor 810 to implement the functions of the joint estimation method of the present application described above.

[0069] In an embodiment of the computing device 800 of the present application, the processor 810 can be a central processing unit (CPU) or other form of processing unit having data processing and / or instruction execution capabilities, which can execute the program instructions stored on the computer-readable storage media to implement the functions of the joint estimation method of the present application described above.

[0070] In an embodiment of the computing device 800 of the present application, the computing device 800 can further include an input device 830 and an output device 840. The input device 830 can be, but is not limited to, a keyboard, a mouse, and the output device 840 can be, but is not limited to, a display, a speaker, a printer. The input device 830 and the output device 840 can be connected to the processor 820 through a bus system.

[0071] Those skilled in the art should understand that the embodiments of the present application described above and shown in the drawings are only examples and do not limit the present application. The purpose of the present application has been fully and effectively achieved. The functional and structural principles of the present application have been demonstrated and described in the embodiments, and the embodiments of the present application can be modified or changed in any way without departing from the principles.

Claims

1. A method for array shape correction and noise source positioning joint estimation of a linear array in rotation, for realizing array shape correction and noise source joint estimation, characterized in that, The joint estimation method comprises the following steps: S1, initially estimating the positions of the elements of the streamer array according to a dynamic method; S2, initially locating the position of the sound source based on a minimum variance distortionless response focused beamforming algorithm; S3, calculating the delay time of each element of the streamer array relative to the first element and the steering vector and array flow pattern matrix according to the estimated position of the sound source; S4, establishing a target cost function and constraint condition based on the calculated array flow pattern matrix to solve the correction amount of each element of the streamer array by optimization; S5, calculating the corrected positions of the elements of the streamer array according to the preliminary estimated positions of the elements under the array shape and the correction amount of each element of the streamer array; S6, performing curve fitting on the positions of the elements based on a second-order polynomial fitting method to obtain the positions of the elements of the streamer array after curve fitting; S7, correcting the array flow pattern matrix based on the new positions of the elements, and locating the position of the sound source again under the new array flow pattern by using the minimum variance distortionless response focused beamforming algorithm. In step S3, the delay time of each array element in the towed array relative to the first array element is calculated based on the estimated sound source position: ,in Indicates the Element to The distance between the sound sources, Indicates the reference element to the The distance between the sound sources, represents the speed of sound, 、 Respectively represent The sound source is axis, The two-dimensional coordinate values ​​on the axis, 、 Respectively represent Array elements in axis, The two-dimensional coordinate values ​​on the axis, Indicates the index of the sound source, 、 Respectively represent the first array element in axis, The two-dimensional coordinate value on the axis, the first array element is used as the reference array element; where the steering vector is calculated by where T denotes transpose, and the angular frequency is , is the frequency of the noise source, denotes the total number of array elements, on the basis of which The formula for the array flow pattern matrix of dimension is where each column of the array flow pattern matrix is the steering vector corresponding to the sound source , is the total number of incoherent sound sources; In the step S4, based on the calculated array flow pattern matrix, the target cost function and constraint conditions are established to optimize the solution of the correction amount of each array element of the towed array, the target cost function is , , , , wherein the array flow pattern matrix when the towed array rotates is , is a , dimensional array flow pattern matrix, , is the two-dimensional coordinate correction amount of the array element position after the array shape correction and the array element position under the preliminary estimated array shape on the axis, , is the two-dimensional coordinate of the array shape on the axis, when the array estimated array shape is consistent with the actual array shape, the space of the array flow pattern matrix is approximately parallel to the space of the array received signal matrix , denotes the Euclidean norm, denotes the index of the array element, denotes the total number of array elements, denotes the maximum value of the array element position correction amount, , denotes the correction amount of the th array element.

2. The method of claim 1, wherein, In the step S1, first, a motion control equation set describing the real-time change of the array shape of the streamer array is established, and the boundary conditions for solving the motion control equation set are determined in combination with the use characteristics of the streamer array; second, the partial differential equation set is discretized into a difference equation set through difference; Then, the numerical solution is solved by numerical calculation method to obtain the preliminary estimated position of the towed array in rotation. After calculation, the preliminary estimated coordinate vector of each array element on the axis is , the preliminary estimated coordinate vector of each array element on the axis is .

3. The method of claim 1, wherein, In the step S2, the calculation formula of the minimum variance distortionless response focusing beamforming algorithm for preliminarily locating the sound source position is as follows: wherein is an array steering vector, is an array covariance matrix, denotes inversion, denotes a spatial spectrum, and according to the peak value of the array spatial spectrum function, the estimated position of the sound source can be estimated wherein , denote the two-dimensional coordinate values of the first sound source on the axis, axis, respectively.

4. The method of claim 1, wherein, In the step S5, the corrected array element position is calculated according to the preliminary estimated array element position and the correction amount of each array element of the streamer array, wherein in the step S4 axis, the array element position calculation formula on the axis is: , wherein , is the two-dimensional coordinate correction amount of the array shape on the axis, axis, , is the two-dimensional coordinate of the array shape on the axis, axis, , is the corrected array element position of the array shape.

5. The method of claim 1, wherein, In the step S6, the positions of the array elements are curve fitted based on a second order polynomial fitting method to obtain the curve fitted positions of the array elements of the streamer array, wherein the solving formula of the second order coefficient, the first order coefficient and the constant term of the second order polynomial is as follows: wherein is the coordinate of the i-th array element of the streamer array on the x-axis, is the i-th element in the position vector of the streamer array, is the coordinate of the i-th array element of the streamer array on the y-axis, is the i-th element in the position vector of the streamer array, is the coordinate of the i-th array element of the streamer array on the z-axis, is the i-th element in the position vector of the streamer array, is the coordinate of the i-th array element of the streamer array on the x-axis, is the i-th element in the position vector of the streamer array, is the coordinate of the i-th array element of the streamer array on the y-axis, is the i-th element in the position vector of the streamer array, is the coordinate of the i-th array element of the streamer array on the z-axis, is the i-th element in the position vector of the streamer array, is the total number of array elements in the streamer array, and represents the index of the array element.

6. The method of claim 1, wherein, In the step S7, the array flow pattern matrix is corrected based on the new array element position, and the calculation formula for positioning the sound source position under the new array flow pattern by using the minimum variance distortionless response focusing beam forming algorithm again is: wherein is the corrected array steering vector, which is a single column in the array flow pattern matrix, is the array covariance matrix, represents inversion, and the estimated position of the sound source can be estimated according to the peak value of the array spatial spectrum function, represents spatial spectrum.

7. A system for array shape correction and noise source localization joint estimation during rotation of a linear array, for implementing array shape correction and noise source joint estimation, characterized in that, The joint estimation method comprises the following steps: The preliminary estimation unit is configured to initially estimate the positions of the elements of the streamer array according to a dynamic method; The preliminary locating unit is configured to initially locate the position of the sound source based on a minimum variance distortionless response focused beamforming algorithm; The first calculation unit is configured to calculate the delay time of each array element in the towed array relative to the first array element based on the estimated sound source position, and calculate the steering vector and the array flow matrix, wherein the delay time of each array element in the towed array relative to the first array element is calculated based on the estimated sound source position as follows: ,in Indicates the Element to The distance between the sound sources, Indicates the reference element to the The distance between the sound sources, represents the speed of sound, 、 Respectively represent The sound source is axis, The two-dimensional coordinate values ​​on the axis, 、 Respectively represent Array elements in axis, The two-dimensional coordinate values ​​on the axis, Indicates the index of the sound source, 、 Respectively represent the first array element in axis, The two-dimensional coordinate value on the axis, the first array element is used as the reference array element, and the calculation formula of the steering vector is: , where T represents the transpose and the angular frequency is , is the frequency of the noise source, Represents the total number of array elements. On this basis, calculate The formula for the manifold matrix of a dimensional array is: , where each column of the array flow matrix corresponds to Steering vector of a sound source , is the total number of incoherent sound sources; The second calculation unit is used to establish the target cost function and constraint conditions based on the calculated array flow matrix to optimize the correction amount of each array element in the tow line array. The target cost function The formula is: , the constraints are: , , , where the array flow matrix when the towed array rotates is , for dimensional array manifold matrix, 、 The position of the array element after formation correction and the position of the array element under the initial estimation formation are axis, The two-dimensional coordinate correction on the axis, 、 For the formation axis, The two-dimensional coordinates on the axis, when the array estimated formation is consistent with the actual formation, the array flow matrix Space and array receiving signal matrix The space is approximately parallel, represents the Euclidean norm, Indicates the index of the array element, Represents the total number of array elements, Indicates the maximum value of the array element position correction, 、 Indicates the The correction amount of each array element; The third calculation unit is configured to calculate the corrected positions of the elements of the streamer array according to the preliminary estimated positions of the elements under the array shape and the correction amount of each element of the streamer array; The fitting unit is configured to perform curve fitting on the positions of the elements based on a second-order polynomial fitting method to obtain the positions of the elements of the streamer array after curve fitting; The sound source locating unit is configured to correct the array flow pattern matrix based on the new positions of the elements, and locate the position of the sound source again under the new array flow pattern by using the minimum variance distortionless response focused beamforming algorithm.

8. A computing device, characterized by The device comprises a processor and a memory, wherein computer program instructions are stored in the memory, and the computer program instructions make the processor execute the joint estimation method when running in the processor.

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