A high-resolution vertical array broadband matching positioning method

Abstract

The present invention relates to the technical field of underwater target acoustic positioning, and in particular to a high-resolution vertical array broadband matching positioning method. A parabolic equation model is used to calculate a single-step recursive sound field propagation matrix, and a sound source-receiver system propagation matrix at different distances is obtained through matrix multiplication. According to the sound source depth search range and the vertical array element position, the corresponding position coefficients of the system propagation matrix are extracted to form a data copy matrix. Subsequently, the data copy matrix is ​​processed, and a broadband filter matrix group is formed by using a least squares estimation method and increasing a diagonal load factor. Finally, a broadband filter matrix group is used to process the vertical array receiving signal, and energy normalization is performed on the processing results of different distances to form a broadband distance-depth ambiguity map, and the target depth and distance estimation results are obtained. The present invention can effectively improve the depth and distance resolution of broadband signal target passive positioning, reduce the sidelobe intensity in the two-dimensional ambiguity map, and reduce the number of high-intensity sidelobes.

Description

Technical Field

[0001] The invention relates to the technical field of underwater target acoustic positioning, and specifically to a high-resolution vertical array broadband matching positioning method. Background Art

[0002] Underwater acoustic target positioning is an important direction and difficult problem in underwater acoustic research. Based on the underwater acoustic propagation characteristics of target radiated noise, passive acoustic positioning of underwater acoustic targets constructs a target-acoustic channel-receiving array correlation model. According to the matching of the model prediction results and the measured results in the actual underwater acoustic environment, different acoustic positioning methods are formed, such as the matching field positioning method based on sound pressure matching, the matching mode positioning method based on the simple normal wave mode, and the matching beam positioning method based on different beam incident energies. The matching field positioning method has been greatly developed with the improvement of the accuracy of the underwater acoustic field prediction model, and has become a major method for acoustic positioning of underwater acoustic targets. The conventional broadband matching field processing method has good robustness and can better adapt to environmental mismatches, but due to its low resolution, high sidelobes, high two-dimensional ambiguity map and large number of noise points, it is difficult to effectively capture the target position in practical applications. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a high-resolution vertical array broadband matching positioning method, which can effectively improve the target depth and distance resolution, reduce the sidelobe intensity in the two-dimensional ambiguity map, and reduce the number of high noise points while maintaining good environmental adaptability.

[0004] To achieve the above object, the present invention provides the following technical solution: a high-resolution vertical array broadband matching positioning method, the steps of which are:

[0005] (1) Use the parabolic equation model to calculate the single-step recursive sound field propagation matrix;

[0006] (2) Then, the propagation matrix of the sound source-receiver system at different distances is obtained through matrix multiplication operation;

[0007] (3) According to the sound source depth search range and the vertical array element position, the corresponding position coefficients of the system propagation matrix are extracted to form a data copy matrix;

[0008] (4) Subsequently, the data copy matrix is ​​processed using the least squares estimation method and increasing the diagonal loading factor to form a broadband filter matrix group;

[0009] (5) Finally, a broadband filter matrix group is used to process the vertical array received signals, and the energy of the processing results at different distances is normalized to form a broadband range-depth ambiguity map to obtain the target depth and distance estimation results.

[0010] In some embodiments, according to step (1), the matrix equation obtained by recursively solving the two-dimensional parabolic equation model is in the following form:

[0011]

[0012] Among them, the matrix T(f, r+Δr) is the propagation matrix at a distance r+Δr from the vertical array at frequency f.

[0013] In some of the embodiments, according to step (2), the system propagation matrix at different distances from the receiving array needs to include the product of all system propagation matrices over the entire transmission distance:

[0014] PM(f,M*Δr)=T(f,M*Δr)T(f,(M-1)*Δr)...T(f,m*Δr)...T(f,2)T(f,1).

[0015] In some of the embodiments, according to step (3), assuming that the sound source is located at a distance m*Δr, the receiving array is located at (1:Nr)*Δz, and the system propagation matrix is ​​a matrix connecting the sound source and the receiving position. When the sound pressure on the receiving array is known, the sound source position can be estimated by the inverse matrix, then:

[0016] P(f, m*Δr, (1: Nr)*Δz)=PM(f, m*Δr, (1: Nr)*Δz, (1: Ns)*Δz)P zs (f, (1:Ns)*Δz).

[0017] In some of the embodiments, according to step (4), the least squares estimation is adopted and the matrix diagonal loading factor is increased to obtain the depth ambiguity estimation results at different frequencies and distances:

[0018] P zs (f, m*Δr, (1:Ns)*Δz)

[0019] =(PM(f,m*Δr) T PM(f,m*Δr)+δI) -1 PM(f,m*Δr) T P(f, m*Δr, (1:Nr)*Δz)

[0020] In the above formula, the symbol (·) T represents the conjugate transpose of the complex matrix, δ is the diagonal loading factor, which can be adjusted according to different signal-to-noise ratios. The lower the signal-to-noise ratio, the larger the diagonal loading factor is set.

[0021] In some embodiments, according to step (5), the depth ambiguity results at different distances are energy-balanced normalized according to the seabed depth:

[0022]

[0023] In some of the embodiments, in order to obtain a broadband gain, broadband energy incoherent superposition is performed on the ambiguity functions obtained at different frequencies, and a broadband two-dimensional ambiguity result can be obtained:

[0024]

[0025] Compared with the prior art, the beneficial effects of the present invention are: it can effectively improve the depth and distance resolution of passive positioning of broadband signal targets, reduce the sidelobe intensity in the two-dimensional ambiguity map, and reduce the number of high-intensity sidelobes. It is highly innovative and has important value for improving the performance of target positioning in actual environments.

[0026] Details of one or more embodiments of the present application are presented in the following drawings and descriptions to make other features, purposes and advantages of the present application more concise and easy to understand. The present application is fully described and understood through the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a diagram of the implementation process of the present invention;

[0028] Figure 2 is a parameter diagram of the ocean waveguide of the present invention;

[0029] Figure 3 It is a sound source localization result diagram of different methods of the present invention;

[0030] Figure 4 This is a diagram of the sound source depth estimation results of different methods of the present invention;

[0031] Figure 5 This is a diagram of the sound source distance estimation results using different methods of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figures 1 to 5The present invention provides a technical solution: a high-resolution vertical array broadband matching positioning method, the steps of which are: first, a single-step recursive sound field propagation matrix is ​​calculated using a parabolic equation model. Then, the propagation matrix of the sound source-receiver system at different distances is obtained through matrix multiplication. Third, according to the sound source depth search range and the vertical array element position, the corresponding position coefficients of the system propagation matrix are extracted to form a data copy matrix. Subsequently, the data copy matrix is ​​processed, and a broadband filter matrix group is formed by using the least squares estimation method and increasing the diagonal load factor. Finally, the vertical array receiving signal is processed using a broadband filter matrix group, and the processing results at different distances are energy normalized to form a broadband distance-depth ambiguity map, and the target depth and distance estimation results are obtained.

[0034] The specific implementation method is as follows:

[0035] (1) The recursive solution of the matrix equation for the two-dimensional parabolic equation model can be written as follows from the most intuitive point of view:

[0036]

[0037] Among them, the matrix T(f, r+Δr) is the propagation matrix at a distance r+Δr from the vertical array at frequency f.

[0038] (2) The system propagation matrix at different distances from the receiving array needs to include the product of all system propagation matrices over the entire transmission distance:

[0039] PM(f,M*Δr)=T(f,M*Δr)T(f,(M-1)*Δr)...T(f,m*Δr)...T(f,2)T(f,1).

[0040] (3) Assuming that the sound source is located at a distance of m*Δr and the receiving array is located at (1:Nr)*Δz, the system propagation matrix is ​​the matrix connecting the sound source and the receiving position. When the sound pressure on the receiving array is known, the sound source position can be estimated by the inverse matrix, which satisfies:

[0041] P(f, m*Δr, (1: Nr)*Δz)=PM(f, m*Δr, (1: Nr)*Δz, (1: Ns)*Δz)P zs (f, (1:Ns)*Δz).

[0042] (4) Using least squares estimation and increasing the matrix diagonal loading factor, the depth ambiguity estimation results at different frequencies and distances can be obtained:

[0043] P zs (f, m*Δr, (1:Ns)*Δz)

[0044] =(PM(f,m*Δr) TPM(f,m*Δr)+δI) -1 PM(f,m*Δr) T P(f, m*Δr, (1:Nr)*Δz)

[0045] In the above formula, the symbol (·) T represents the conjugate transpose of the complex matrix, δ is the diagonal loading factor, which can be adjusted according to different signal-to-noise ratios. The lower the signal-to-noise ratio, the larger the diagonal loading factor is set.

[0046] (5) According to the seabed depth, the depth ambiguity results at different distances are normalized for energy balance:

[0047]

[0048] (6) In order to obtain broadband gain, the broadband energy incoherent superposition of the ambiguity functions obtained at different frequencies can be performed to obtain the broadband two-dimensional ambiguity result:

[0049]

[0050] Through this technical solution,

[0051] Figure 1 This is the implementation process diagram of this patent. The split step parabola matrix equation is used to calculate the transfer matrix at different step distances, and then the system propagation matrix group at different distances is calculated. The data copy matrix is ​​formed according to the sound source depth and the receiving array position. The least squares estimation method is used and the diagonal load factor that satisfies the white noise gain is increased to form a broadband matrix filter group at different distances. Subsequently, the matrix filter group is used to process the vertical array receiving signal, and the energy of the processing results at different distances is normalized, and finally a broadband distance-depth ambiguity map is formed to obtain the target positioning result.

[0052] Figure 2 This is a diagram of ocean waveguide parameters, which shows the ocean geoacoustic parameters and sound source information. The broadband sound source frequency range is 200Hz~250Hz, and 11 frequency points are selected, namely 200Hz, 205Hz, 210Hz, 215Hz, 220Hz, 225Hz, 230Hz, 235Hz, 240Hz, 245Hz, and 250Hz. The vertical array is a 20-element array with an element spacing of 3m and a depth of 3m for the first element. The sound source depth is 50m and the distance is 9.1km.

[0053] Figure 3 The results obtained by using a conventional broadband matching processor and the patented method are given. It can be seen that the target position is more concentrated in the calculation results of the patented method, proving that the depth-range resolution is high, while the number of high-intensity noise points is greatly reduced, and the intensity of the side lobes outside the main lobe is reduced.

[0054] Figure 4 The depth-intensity results at the sound source distance calculated by the two methods are given. It can be seen that the target depth main lobe width is narrower, the resolution is higher, and the side lobe intensity is lower in the calculation results of the patent method.

[0055] Figure 5 The distance-intensity results at the sound source distance calculated by the two methods are given. It can be seen that the target distance main lobe width is narrower, the resolution is higher, and the side lobe intensity is lower in the calculation results of the patent method.

[0056] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

[0057] 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 high-resolution vertical array broadband matching positioning method, characterized in that: The steps are: (1) Use the parabolic equation model to calculate the single-step recursive sound field propagation matrix; (2) Then, the propagation matrix of the sound source-receiver system at different distances is obtained through matrix multiplication operation; (3) According to the sound source depth search range and the vertical array element position, the corresponding position coefficients of the system propagation matrix are extracted to form a data copy matrix; (4) Subsequently, the data copy matrix is ​​processed using the least squares estimation method and increasing the diagonal loading factor to form a broadband filter matrix group; (5) Finally, a broadband filter matrix group is used to process the vertical array received signals, and the energy of the processing results at different distances is normalized to form a broadband range-depth ambiguity map to obtain the target depth and distance estimation results.

2. A high-resolution vertical array broadband matching positioning method according to claim 1, characterized in that: According to step (1), the matrix equation of the two-dimensional parabolic equation model is recursively solved in the following form: Among them, the matrix T(f, r+Δr) is the propagation matrix at a distance r+Δr from the vertical array at frequency f.

3. A high-resolution vertical array broadband matching positioning method according to claim 2, characterized in that: According to step (2), the system propagation matrix at different distances from the receiving array needs to contain the product of all system propagation matrices over the entire transmission distance: PM(f,M*Δr)=T(f,M*Δr)T(f,(M-1)*Δr)...T(f,m*Δr)...T(f,2)T(f,1).

4. A high-resolution vertical array broadband matching positioning method according to claim 3, characterized in that: According to step (3), assuming that the sound source is located at a distance of m*Δr and the receiving array is located at (1:Nr)*Δz, the system propagation matrix is ​​the matrix connecting the sound source and the receiving position. When the sound pressure on the receiving array is known, the sound source position can be estimated by the inverse matrix, which satisfies: P(f,m*Δr,(1:Nr)*Δz)=PM(f,m*Δr,(1:Nr)*Δz,(1:Ns)*Δz)P zs (f,(1:Ns)*Δz)。 5. A high-resolution vertical array broadband matching positioning method according to claim 4, characterized in that: According to step (4), the least squares estimation is adopted and the matrix diagonal loading factor is increased to obtain the depth ambiguity estimation results at different frequencies and distances: P zs (f,m*Δr,(1:Ns)*Δz)=(PM(f,m*Δr) T PM(f,m*Δr)+δI) -1 PM(f,m*Δr) T P(f,m*Δr,(1:Nr)*Δz) In the above formula, the symbol (·) T represents the conjugate transpose of the complex matrix, δ is the diagonal loading factor, which is adjusted according to different signal-to-noise ratios. The lower the signal-to-noise ratio, the larger the diagonal loading factor is set.

6. A high-resolution vertical array broadband matching positioning method according to claim 5, characterized in that: According to step (5), the depth ambiguity results at different distances are energy-balanced and normalized according to the seabed depth:

7. A high-resolution vertical array broadband matching positioning method according to claim 6, characterized in that: In order to obtain broadband gain, the ambiguity functions obtained at different frequencies are subjected to broadband energy incoherent superposition to obtain the broadband two-dimensional ambiguity result:

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