Low-frequency sound source three-dimensional passive positioning method for deep-sea small-aperture array

Abstract

The invention discloses a low-frequency sound source three-dimensional passive positioning method for a deep-sea small-aperture array, and belongs to the technical field of ocean engineering, underwater acoustic engineering, array signal processing and sonar technologies, and the method comprises the following steps: S1, setting initial parameters of the small-aperture array; s2, carrying out super-directivity azimuth estimation on the small-aperture array; s3, performing super-directivity matching field positioning by using the small-aperture array; s4, estimating the target depth by using estimation results of S2 and S3 and a small-aperture array beam output result; according to the method, the limitation that a conventional scalar array cannot obtain the target azimuth, distance and depth information at the same time under the condition of a smaller array aperture is broken through, the target azimuth and distance information can be obtained at the same time with a smaller aperture, the target depth information is obtained according to the known target azimuth and distance information, the method has better azimuth estimation performance, and the method is suitable for being used in a large scale. And the device is convenient to lay and recycle, wider in application range and lower in cost.

Description

Technical Field

[0001] The invention belongs to the technical fields of ocean engineering, hydroacoustic engineering, array signal processing and sonar technology, and specifically relates to a three-dimensional passive positioning method for low-frequency sound sources of a deep-sea small-aperture array. Background Art

[0002] Passive positioning of low-frequency targets in deep-sea environments is of great significance to the development of marine resources, underwater acoustic detection and other fields. For low-frequency targets, a large-aperture vertical array is often used for distance estimation and depth estimation, and a horizontal array is used for horizontal angle estimation. Due to the limitation of the array, when only one set of traditional scalar receiving array is used, it is often impossible to obtain the three types of information of the azimuth, distance and depth of the low-frequency sound source at the same time.

[0003] In order to obtain three-dimensional information of passive sound sources, a Chinese patent (publication number: CN202211256111.X) discloses a three-dimensional positioning method for passive sound sources suitable for deep-sea direct sound zone environments. This method is a distributed array, requiring the distance between any two sensors to be no less than 2 km, and the total number of sensors to be no less than 5. The aperture of the distributed array is too large, and practical application is difficult; 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 paths. This method can only obtain target distance and depth information, but cannot estimate the target orientation, and cannot accurately locate the target under small array apertures. For example, a Chinese patent (publication number: CN202211256111.X) discloses a passive moving sound source three-dimensional positioning method suitable for deep-sea direct sound zone environment. This method is only applicable to moving targets and requires two sets of large-aperture horizontal receiving arrays located on the seabed. The method has low applicability; For example, a Chinese patent (publication number: CN201210468673.0) proposes a passive positioning method based on a single vector hydrophone. This method can only estimate the target's azimuth and velocity, and the azimuth of the target can only be estimated using the sound pressure signal and horizontal vibration velocity signal received by the single vector hydrophone, so the azimuth estimation performance is poor. For example, a Chinese patent (publication number: CN202310501124.7) provides a three-dimensional positioning method and device, but this method also only uses sound pressure signals and horizontal vibration velocity signals to estimate the target azimuth, and the azimuth estimation performance is poor. In addition, a large-aperture vector vertical array is used, which is costly and difficult to deploy and recover. Therefore, a three-dimensional passive positioning method for low-frequency sound sources using a deep-sea small-aperture array is needed to solve the above problems. Summary of the invention

[0004] The object of the present invention is to provide a three-dimensional passive positioning method for low-frequency sound sources of a deep-sea small-aperture 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 three-dimensional passive positioning method for low-frequency sound sources of a deep-sea small-aperture array, comprising the following steps: S1. Set the initial parameters of the small aperture array; S2, small aperture array for super-directional azimuth estimation; S3, using small aperture array for super-directional matching field positioning; S4. Estimate target depth using a small aperture array.

[0006] This method uses a super-directional azimuth estimation method to obtain a horizontal angle estimate; then uses a super-directional matching field positioning method to obtain target distance information; given the estimated values ​​of the target horizontal angle and elevation angle, a beam output is performed on the received signal to improve the signal-to-noise ratio of the received signal, and the beam output result of a single channel is extracted and processed for cepstrum processing to estimate the time delay difference, which is then matched with the multi-path arrival time delay difference simulated by the ray model to obtain the target depth value.

[0007] As a preferred solution, in "S1", a small aperture array is set, the number of array elements is M, the hydrophone is non-directional, and the array manifold vector is set and , where , , 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; assuming From the direction The actual received data is N snapshots of the plane wave signal incident from the direction. ,in is random noise that is uncorrelated with the signal.

[0008] As a preferred solution, in "S2", a super-directional azimuth estimation method is used to localize the sound source. For the super-directional azimuth estimation method, the distortion-free response constraint of minimizing the received data output is: , ,in is the weight vector, The array receives the data sampling covariance matrix, which is , the azimuth spectrum of the super-directional azimuth estimation method is The azimuth spectrum peak is the angle estimation value of the low-frequency passive sound source. The super-directional azimuth estimation method is used to simultaneously estimate and Make an estimate.

[0009] As a preferred solution, in "S3", a super-directional matching field positioning method is used to measure the target distance, and the target position is set to , 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 by ray theory using the Calculate and get the estimated value of pitch angle , estimate the target pitch angle, and the estimation result and Matching is performed, and the most suitable result is the target position .

[0010] As a preferred solution, in "S3", a small aperture array is used to perform super-directional matching field positioning. After obtaining the target horizontal angle estimate, the array manifold vector is optimized, and the horizontal angle is the estimation result of “S2”; the multi-path arrival structure is obtained by using the ray model, and the pitch angle estimation value of the super-directivity azimuth estimation is matched with the multi-path arrival angle calculated by the ray model to obtain a two-dimensional fuzzy plane of depth and distance. The bright spot is the target positioning estimation result.

[0011] As a preferred solution, in "S4", the multi-path arrival structure is obtained by ray model simulation. The target horizontal angle and distance information, that is, the target horizontal angle and elevation angle are known. By beaming the received signal, the signal-to-noise ratio of the received signal is improved and the error of the small aperture array depth estimation is reduced. At this time, the beam output result is , select the beam output result of the central element of the small aperture receiving array to perform cepstrum to obtain the delay difference , and match it with the delay difference obtained by the simulation result. The depth corresponding to the minimum value number is the depth estimation value.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention breaks through the limitation that conventional scalar arrays cannot simultaneously obtain target azimuth, distance and depth information under the condition of smaller array aperture. It can simultaneously obtain target azimuth and distance information with a smaller aperture, and obtain target depth information based on known target azimuth and distance information. It has good azimuth estimation performance, is easy to deploy and recover, has a wider range of applications and is low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a flow chart of the small aperture array three-dimensional passive positioning method of the present invention; Figure 2 The three-dimensional view and top view of the five-layer cylindrical array structure of the present invention Figure 3 It is the result diagram of the position and distance estimation of the present invention; Figure 4 It is a schematic diagram of distance measurement of the super-directional matching field positioning method of the present invention; Figure 5 This is a spectrum diagram of the beam output signal of the present invention; Figure 6 This is the beam output cepstrum result diagram of the present invention; Figure 7 This is the depth estimation map of the present invention. DETAILED DESCRIPTION

[0014] The present invention will be further described below in conjunction with the embodiments.

[0015] 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.

[0016] See also Figure 1-7 The present invention provides a three-dimensional passive positioning method for low-frequency sound sources of a deep-sea small-aperture array, comprising the following steps: S1. Set the initial parameters of the small aperture array; Set the small aperture array type. The simulation uses a small aperture cylindrical array with a number of array elements. , from top to bottom, there are one to five layers, each layer has 8 hydrophones evenly arranged, with a diameter of 6 meters and a spacing of 1 meter between each layer. The coordinates of the array element positions are as follows Figure 2 As shown; set the array manifold vector , where , , 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; assuming For The actual received data is N snapshots of the plane wave signal incident from the direction. ,in It is random noise unrelated to the signal, and the signal-to-noise ratio of the received data is 30dB.

[0017] Ray model simulation conditions: Use the BELLHOP acoustic toolbox to 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, water velocity near the water-sediment interface is 1567m / s, sediment thickness is 50m, the seabed consists of sediment and basement layers, the signal is 250Hz line spectrum, sound source depth 50m, the distance between the sound source and the receiving array is 7km; S2, small aperture array for super-directional azimuth estimation; The super-directional azimuth estimation method is used to locate the sound source. For the super-directional azimuth estimation method, the distortion-free response constraint of minimizing the received data output is: and ,in is the weight vector, The array receives the data sampling covariance matrix, which is , the azimuth spectrum of the super-directional azimuth estimation method is The azimuth spectrum peak is the angle estimation value of the low-frequency passive sound source. The super-directional azimuth estimation method is used to estimate the Make an estimate.

[0018] S3, using a small aperture array to perform super-directional matching field positioning, after obtaining the target horizontal angle estimate, optimize the array manifold vector, horizontal angle The result of "S2" estimation; the multi-path arrival structure is obtained by BELLHOP simulation, and the target distance is measured by the super-directional matching field positioning method to set the target position , 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 by ray theory using the Calculate and get the estimated value of pitch angle , estimate the target pitch angle, and the estimation result and Matching is performed, and the most suitable result is the target position , define the fuzzy plane of the super-directional matching field positioning method and perform normalization: , at which point a blurred plane of distance and depth is drawn.

[0019] S4, using a small aperture array to estimate target depth; The multi-path arrival structure is obtained through the "S3" ray model, and the time delay information of the direct wave and the first reflection wave on the sea surface is extracted respectively, and the time delay difference matrix of the direct wave and the first reflection wave on the sea surface of the receiving array center element under different sound source depth conditions is obtained. , where R represents the distance grid number, and D represents the sound source depth grid number. At this time, the target horizontal angle and distance are known according to "S2 and S3". At this time, the grid number corresponding to the distance estimate is selected The time delay difference between the direct wave and the first reflected wave from the sea surface , the array acquisition signal is beamed out, and the beam output result is , select the beam output result of the central element of the receiving array for cepstrum analysis, and the cepstrum is , find the corresponding peak in the cepstrum, which is the delay of the corresponding multi-path arrival sound line, and calculate the delay difference , match it with the simulation result, minimize the measured value and the calculated value, and average the minimum value obtained by multiple cycles to obtain the depth estimate: .

[0020] The working principle and use process of the present invention are as follows: first, the initial parameters of the small aperture array are set, and then the small aperture array is used to perform super-directivity azimuth estimation and super-directivity matching field positioning in sequence, and finally the small aperture array is used to estimate the target depth, and the multi-path arrival structure is obtained by BELLHOP simulation. The target horizontal angle and distance information, that is, the target horizontal angle and pitch angle are known. By beaming the received signal, the signal-to-noise ratio of the received signal is improved, and the error of the small aperture array depth estimation is reduced. At this time, the beam output result is , select the beam output result of the central element of the small aperture receiving array to perform cepstrum to obtain the delay difference , and match it with the delay difference obtained by the simulation result. The depth corresponding to the minimum value number is the depth estimation value.

[0021] 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 three-dimensional passive positioning method for low-frequency sound sources of a deep-sea small-aperture array, characterized in that: The following steps are involved: S1. Set the initial parameters of the small aperture array; S2, small aperture array for super-directional azimuth estimation; S3, using small aperture array for super-directional matching field positioning; S4. Estimate target depth using a small aperture array.

2. The method for three-dimensional passive positioning of low-frequency sound sources using a deep-sea small-aperture array according to claim 1, characterized in that: In step S1, a small aperture array is set, the number of array elements is M, the hydrophone is non-directional, and the array manifold vector is set and , where , , 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.

3. The method for three-dimensional passive positioning of low-frequency sound sources using a deep-sea small-aperture array according to claim 1, characterized in that: In step S2, a super-directional azimuth estimation method is used to locate the sound source. For the super-directional azimuth estimation method, the distortion-free response constraint of minimizing the received data output is: , ,in is the weight vector, The array receives the data sampling covariance matrix, which is , the azimuth spectrum of the super-directional azimuth estimation method is The azimuth spectrum peak is the angle estimation value of the low-frequency passive sound source. The super-directional azimuth estimation method is used to simultaneously estimate and Make an estimate.

4. The method for three-dimensional passive positioning of low-frequency sound sources of a deep-sea small-aperture array according to claim 1 is characterized in that: In step S3, the target distance is measured by using the super-directional matching field positioning method, and the target position is set to , 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 by ray theory using the Calculate and get the estimated value of pitch angle , estimate the target pitch angle, and the estimation result and Matching is performed, and the most suitable result is the target position .

5. The method for three-dimensional passive positioning of low-frequency sound sources using a deep-sea small-aperture array according to claim 1, characterized in that: In step S3, a small aperture array is used to perform super-directional matching field positioning, and after obtaining the target horizontal angle estimation value, the array manifold vector is optimized, and the horizontal angle is the "S2" estimation result; the multi-path arrival structure is obtained by using the ray model, and the pitch angle estimation value of the super-directivity azimuth estimation is matched with the multi-path arrival angle calculated by the ray model to obtain a two-dimensional fuzzy plane of depth and distance. The bright spot is the target positioning estimation result.

6. The method for three-dimensional passive positioning of low-frequency sound sources using a deep-sea small-aperture array according to claim 1, characterized in that: In step S4, the multi-path arrival structure is obtained by ray model simulation. The target horizontal angle and distance information are known, that is, the target horizontal angle and elevation angle are known. By beaming the received signal, the signal-to-noise ratio of the received signal is improved and the error of the small aperture array depth estimation is reduced. At this time, the beam output result is , select the beam output result of the central element of the small aperture receiving array to perform cepstrum to obtain the delay difference , and match it with the delay difference obtained from the simulation results. The depth corresponding to the minimum value number is the depth estimation value.

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