Low-frequency sound source passive positioning method for deep-sea small-scale vertical array

Abstract

The invention discloses a low-frequency sound source passive positioning method for a deep-sea small-scale vertical array, which belongs to the technical field of ocean engineering and comprises the following steps: S1, setting initial parameters; s2, combining the sound field generation signal with the isotropic noise; s3, positioning by using a sparse reconstruction matching field positioning method; s4, changing the number of array elements and the condition of array element spacing, and circulating S2 and S3 to obtain a root mean square error curve of distance and depth of the SR-MF method under different conditions; according to the method, the distance and depth information of the low-frequency passive sound source can be obtained under the deep sea condition through the SR-MF method, multi-path number and angle estimation is effectively avoided, a good positioning estimation result can be obtained under a small array scale, the influence of the sound field on the positioning performance of a large-scale array can be effectively avoided, and the positioning accuracy of the low-frequency passive sound source is improved. And moreover, the cost of the adopted array is lower, and the arrangement and the recovery are more convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of marine engineering, and in particular relates to a low-frequency sound source passive positioning method of a deep-sea small-scale vertical array. Background Art

[0002] Passive positioning of low-frequency targets in deep-sea environments is of great significance to the fields of marine resource development and underwater acoustic detection. Large-scale arrays are often used to estimate distance and depth of low-frequency targets. However, as the array scale increases, the tilt and distortion of the array and the decrease in the correlation of the array received signal will lead to reduced positioning performance. In addition, too large a scale will lead to a significant increase in cost and more difficult deployment and recovery.

[0003] For example, the paper “Research on reliable acoustic path_ Physical properties and a source localization method, Chinese Physics B 21(12) 2012” mentions a passive target localization method suitable for reliable acoustic path. This method has good positioning performance, but has high requirements on array scale. When a small-scale array is used for positioning, this method will fail. For example, a Chinese patent (publication number: CN105629220B) discloses a deep seawater acoustic passive ranging method based on a single hydrophone. This method can only estimate the target distance and requires the frequency domain interval of each time segment fringes obtained by the receiving hydrophone to match the frequency domain interference period of the sound field at different distances. This method has high requirements on the signal-to-noise ratio. For example, a Chinese patent (publication number: CN116540220A) discloses a three-dimensional passive positioning method and device for a target. This method uses a large-scale vector vertical array, which is costly and difficult to deploy and recover; Therefore, a low-frequency sound source passive positioning method of a deep-sea small-scale vertical array is needed to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a method for passively locating low-frequency sound sources of a deep-sea small-scale vertical array to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for passively locating low-frequency sound sources of a deep-sea small-scale vertical array, comprising the following steps: S1, initial parameter setting; S2, combining the sound field to generate a signal and isotropic noise; S3, positioning using sparse reconstruction matching field positioning method; S4. Change the number of array elements and the array element spacing conditions, repeat S2 and S3, and obtain the distance and depth root mean square error curves of the SR-MF method under different conditions.

[0006] This method uses a small-scale array to receive signals to estimate the distance and depth of low-frequency passive sound sources, breaking through the limitations of traditional deep-sea scalar arrays on array scale, and achieving better positioning effects under smaller array scale conditions. It can effectively avoid the reduction of signal correlation of large-scale arrays under the influence of the sound field and the positioning error caused by array tilt in actual situations. The public method has small positioning error, low manufacturing cost, and easy deployment and recovery.

[0007] As a preferred solution, in "S1", set the small-scale vertical array parameters, the number of array elements M, the hydrophone is non-directional, and the array manifold vector is set , .

[0008] As a preferred solution, in "S1", , , is the pitch angle, is the horizontal angle, , represents the wavelength of the incident plane wave, is the coordinate position of the mth array element.

[0009] As a preferred solution, in "S2", combined with the sound field model, the ray method is used to calculate the multi-path arrival structure of each hydrophone in the vertical array, only considering the direct wave and the single reflection wave of the sea surface, and the other multi-path arrival structures are ignored.

[0010] As a preferred solution, in "S2", the array manifold vector is modified using the multipath arrival structure obtained by simulating each hydrophone. At this time, the single-frequency target signal is simulated. , the signal amplitude is the signal amplitude of the multipath arrival structure corresponding to each hydrophone, then the vertical array receiving data is .

[0011] As a preferred solution, in "S2", To use the array manifold vector after sound field correction, Represents any moment, It is isotropic noise that is uncorrelated with the signal.

[0012] As a preferred solution, in "S3", the array receives the signal Perform singular value decomposition and dimensionality reduction to obtain The matrix , where K is the number of information sources, It can be expressed as ,in , To receive the signal to the array The left unitary matrix and diagonal matrix obtained by singular value decomposition, The expression is , for The identity matrix of The dimension is The zero matrix of , T is the number of snapshots, Transformable to ,in, , , Receive signal for array The right unitary matrix obtained by singular value decomposition uses the joint minimization model to obtain the azimuth spectrum solution formula of the SR algorithm: , where represents the matrix F-norm, is the regularization parameter, and the final azimuth spectrum obtained by the SR algorithm is .

[0013] Combining the idea of ​​matching field passive positioning method, the SR-MF method is proposed to passively locate the target. Assuming the target position is , where z is the depth of the target from the sea surface, r is the horizontal distance of the target from the array, and the multipath arrival angle of the signal is ,in Determined by the environment, it can be calculated using the ray model. Bring in , define the blur plane of SR-MF and perform normalization to obtain the target positioning estimation result.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention can obtain the distance and depth information of low-frequency passive sound sources under deep-sea conditions through the SR-MF method, effectively avoid the estimation of the number and angle of multipath, obtain better positioning estimation results at a smaller array scale, effectively avoid the influence of the sound field on the positioning performance of the large-scale array, and the tilt problem after the large-scale array is deployed, and the array cost is lower and the deployment and recovery are more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a flow chart of the present invention; Figure 2 A diagram showing the change of sound speed with sea depth in the simulation scenario of the present invention; Figure 3 This is a propagation loss diagram of the present invention in a simulated deep sea environment; Figure 4 This is the SR-MF positioning result diagram of the present invention.

[0016] Figure 5 For the present invention and Figure 3 WSF-MF positioning results under the same conditions.

[0017] Figure 6 This is a diagram showing the root mean square error results of the distances of SR-MF and WSF-MF under different signal-to-noise ratio conditions in 100 independent repeated tests of the present invention.

[0018] Figure 7 This is a diagram showing the root mean square error results of the SR-MF and WSF-MF distances under different array element spacing conditions in 100 independent repeated tests of the present invention.

[0019] Figure 8 This is a graph showing the depth root mean square error results of SR-MF and WSF-MF under different signal-to-noise ratio conditions of 100 independent repeated experiments of the present invention.

[0020] Fig. 9 This is a graph showing the depth root mean square error results of SR-MF and WSF-MF under different array element spacing conditions of 100 independent repeated tests of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the embodiments.

[0022] The following examples are used to illustrate the present invention, but they cannot be used to limit the scope of protection of the present invention. The conditions in the examples can be further adjusted according to specific conditions. Simple improvements to the method of the present invention under the premise of the concept of the present invention belong to the scope of protection claimed in the present invention.

[0023] See also Figure 1-9 The present invention provides a method for passively locating low-frequency sound sources of a deep-sea small-scale vertical array, comprising the following steps: S1, initial parameter setting; Set the small-scale vertical array parameters. The simulation uses a small-scale vertical array with the number of array elements. , array element spacing , array size , the signal incident direction is , the signal is a 100Hz line spectrum, the signal-to-noise ratio is 30dB, the sound source depth is 70m, and the distance between the sound source and the receiving array is 10km; S2, combining the sound field to generate a signal and isotropic noise; Use the ray model to obtain the multi-path arrival structure and divide the distance grid (Unit: km), divide the sound source depth grid (Unit: m), receiving array depth 4200m, sea depth 5000m, using Munk sound velocity profile, sediment layer sound velocity , neglect, , , the thickness of the sediment layer The seabed is composed of sedimentary layers and basement layers. The multi-path arrival structure only considers the direct wave and the first sea surface reflection wave, and the other multi-paths are ignored. To ensure the sparseness of the signal model, the scanning grid is set to , then , where K is the number of signal sources. Combined with the acoustic field model, the ray method is used to calculate the multipath arrival structure of each hydrophone in the vertical array. Only the direct wave and the first reflection wave of the sea surface are considered, and the other multipath arrival structures are ignored. The multipath arrival structure simulated by each hydrophone is used to correct the array manifold vector. At this time, the simulated single-frequency target signal , the signal amplitude is the signal amplitude of the multipath arrival structure corresponding to each hydrophone, then the vertical array receiving data is ,in To use the array manifold vector after sound field correction, Represents any moment, It is isotropic noise that is uncorrelated with the signal.

[0024] S3, positioning using sparse reconstruction matching field positioning method; Receive signal to array Perform singular value decomposition and dimensionality reduction to obtain The matrix , It can be expressed as ,in , To receive the signal to the array The left unitary matrix and diagonal matrix obtained by singular value decomposition, The expression is , for The identity matrix of The dimension is The zero matrix of , T is the number of snapshots. Transformable to ,in, , , Receive signal for array The right unitary matrix obtained by singular value decomposition. At this time, the sparse signal reconstruction algorithm is used Get the azimuth spectrum solution formula of the SR algorithm , where represents the matrix F-norm, is the regularization parameter. The azimuth spectrum obtained by the final SR algorithm is .

[0025] Combining the idea of ​​matching field passive positioning method, the SR-MF method is proposed for passive target positioning. Assuming the target position is , where z is the depth of the target from the sea surface and r is the horizontal distance of the target from the array. The multipath arrival angle of the signal is a function of the target position and is ,in Determined by the environment, it can be calculated using the ray model. Bring in , find the target position by searching the divided distance-depth grid , define the blur plane of SR-MF and perform normalization: , at this time, a blurred plane of distance and depth is drawn, such as Figure 4 As shown, in The position corresponding to the maximum value in is the target positioning estimation result; S4, positioning performance analysis of SR-MF method; The distance root mean square error and depth root mean square error are used to analyze the distance estimation error of the SR-MF passive positioning method under different conditions.

[0026] in represents the depth estimation result of the SR-MF passive positioning method of the i-th independent experiment, It represents the distance estimation result of the SR-MF passive positioning method of the i-th independent experiment. The units of depth and distance estimation results are both meters.

[0027] exist Figure 4 , Figure 5 In the figure, the white asterisk indicates the true location of the sound source; exist Figure 6 In the array, the array element spacing sampling , receiving distance 10km, sound source depth 70m, RMSE less than 1000m is considered to be accurate positioning (10% error).

[0028] exist Figure 7 In the array, the array element spacing sampling , receiving distance 10km, sound source depth 70m, RMSE less than 1000m is considered to be accurate positioning (10% error).

[0029] exist Figure 8 In the array, the array element spacing sampling , receiving distance 10km, sound source depth 70m, RMSE less than 50m is considered to be accurate positioning.

[0030] exist Fig. 9 In the array, the array element spacing sampling , receiving distance 10km, sound source depth 70m, RMSE less than 50m is considered to be accurate positioning.

[0031] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for passively locating low-frequency sound sources using a deep-sea small-scale vertical array, characterized in that: The following steps are involved: S1, initial parameter setting; S2, combining the sound field to generate a signal and isotropic noise; S3, positioning using sparse reconstruction matching field positioning method; S4. Change the number of array elements and the array element spacing conditions, repeat S2 and S3, and obtain the distance and depth root mean square error curves of the SR-MF method under different conditions.

2. The method for passively locating low-frequency sound sources of a deep-sea small-scale vertical array according to claim 1 is characterized in that: In "S1", set the small-scale vertical array parameters, the number of array elements M, the hydrophone is non-directional, and set the array manifold vector , .

3. The method for passively locating low-frequency sound sources of a deep-sea small-scale vertical array according to claim 2 is characterized in that: In "S1", , , is the pitch angle, is the horizontal angle, , represents the wavelength of the incident plane wave, is the coordinate position of the mth array element.

4. The method for passively locating low-frequency sound sources of a deep-sea small-scale vertical array according to claim 1 is characterized in that: In "S2", combined with the acoustic field model, the ray method is used to calculate the multipath arrival structure of each hydrophone in the vertical array. Only the direct wave and the first reflection wave of the sea surface are considered, and the other multipath arrival structures are ignored.

5. The method for passively locating low-frequency sound sources of a deep-sea small-scale vertical array according to claim 4 is characterized in that: In "S2", the array manifold vector is modified using the multipath arrival structure obtained from the simulation of each hydrophone. At this time, the single-frequency target signal is simulated. , the signal amplitude is the signal amplitude of the multipath arrival structure corresponding to each hydrophone, then the vertical array receiving data is .

6. The method for passively locating low-frequency sound sources of a deep-sea small-scale vertical array according to claim 5 is characterized by: In "S2", To use the array manifold vector after sound field correction, Represents any moment, It is isotropic noise that is uncorrelated with the signal.

7. The method for passively locating low-frequency sound sources of a deep-sea small-scale vertical array according to claim 1 is characterized by: In "S3", the array receives the signal Perform singular value decomposition and dimensionality reduction to obtain The matrix , where K is the number of information sources, It can be expressed as ,in , To receive the signal to the array The left unitary matrix and diagonal matrix obtained by singular value decomposition, The expression is , for The identity matrix of The dimension is The zero matrix of , T is the number of snapshots, Transformable to ,in, , , Receive signal for array The right unitary matrix obtained by singular value decomposition uses the joint minimization model to obtain the azimuth spectrum solution formula of the SR algorithm: , where represents the matrix F-norm, is the regularization parameter, and the final azimuth spectrum obtained by the SR algorithm is .

Images