Target signal direction estimation method and system of vector hydrophone

Abstract

The invention discloses a target signal direction estimation method and system for a vector hydrophone, and the method comprises the steps: obtaining a combined vibration velocity through a guiding direction according to the vibration velocity of the vector hydrophone; establishing a trigonometric function equation of the target signal direction according to the combined vibration velocity; and obtaining a target signal direction according to the trigonometric function equation. The problem that an existing vector hydrophone interference suppression method can only suppress interference but cannot measure the target orientation is solved, and estimation of the target orientation is achieved while interference is suppressed and the target signal detection capacity is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater signal detection and estimation, and specifically relates to a method and system for estimating the direction of a target signal of a vector hydrophone. Background Art

[0002] When detecting weak underwater target signals, it is often very difficult due to being masked by strong interference. By jointly processing sound pressure and vibration velocity, a vector hydrophone can form a beam null to align with the interference, greatly weakening the interference and thus improving the signal detection ability.

[0003] Although the beam null method of a vector hydrophone can suppress interference, it cannot orient the target. As long as the incident direction of the target deviates from the interference direction by a certain angle, when the beam null aligns with the interference, the interference can be suppressed and the signal detection ability can be improved, but it is difficult to know from which direction the signal is incident with the existing methods. Summary of the Invention

[0004] In view of this, the present invention provides a method and system for estimating the direction of a target signal of a vector hydrophone, which can, while suppressing interference and improving the target signal detection ability, realize the estimation of the target azimuth.

[0005] The specific technical solution adopted by the present invention is as follows:

[0006] A method for estimating the direction of a target signal of a vector hydrophone includes: obtaining a combined vibration velocity through a guiding direction according to the vibration velocity of the vector hydrophone; establishing a trigonometric function equation for the direction of the target signal according to the combined vibration velocity; and obtaining the direction of the target signal according to the trigonometric function equation.

[0007] Further, the obtaining a combined vibration velocity through a guiding direction according to the vibration velocity of the vector hydrophone includes: according to the components v x (n) and v y (n) of the vibration velocity in the x and y directions, obtaining the combined vibration velocities v and v c and v s by setting the guiding direction:

[0008]

[0009]

[0010] where n = 0,..., N - 1, and N is the length of one frame of data.

[0011] Further, the establishing a trigonometric function equation for the direction of the target signal according to the combined vibration velocity includes: canceling the combined vibration velocity v cThe interference part to obtain the remaining signal p(n) - v c (n, α1), where α1 represents the interference direction; for the remaining signal and the combined vibration velocity v s Integrate to obtain the trigonometric function equation of the target signal direction:

[0012]

[0013] Where α2 represents the target signal direction, and c represents the integration ratio, which is a positive number.

[0014] Further, obtaining the target signal direction according to the trigonometric function equation includes:

[0015] Using a numerical method to solve the trigonometric function equation, when Reaches the minimum value, α2 is the estimated target signal direction obtained.

[0016] Further, using a numerical method to solve the trigonometric function equation includes: α2 traverses the range of 0 - 360° with a preset step size to obtain the minimum value.

[0017] A target signal direction estimation system for a vector hydrophone, including: a vibration velocity acquisition module for obtaining a combined vibration velocity through a guiding direction according to the vibration velocity of the vector hydrophone; a function establishment module for establishing a trigonometric function equation of the target signal direction according to the combined vibration velocity; a target direction acquisition module for obtaining the target signal direction according to the trigonometric function equation.

[0018] Further, in the vibration velocity acquisition module, according to the components v x (n) and v y (n) of the vibration velocity in the x and y directions, by setting the guiding direction Obtain the combined vibration velocity v c And v s :

[0019]

[0020]

[0021] Where n = 0,..., N - 1, N, and N is the length of one frame of data.

[0022] Further, in the function establishment module, according to the sound pressure p(n) of the vector hydrophone, cancel the interference part of the combined vibration velocity v c To obtain the remaining signal p(n) - v c (n, α1), where α1 represents the interference direction; for the remaining signal and the combined vibration velocity v sIntegrate to obtain the trigonometric function equation of the target signal direction:

[0023]

[0024] Wherein, α2 represents the target signal direction, and c represents the integration ratio, which is a positive number.

[0025] Furthermore, in the target direction acquisition module,

[0026] Adopt a numerical method to solve the trigonometric function equation. When reaches the minimum value, α2 is the estimated target signal direction obtained.

[0027] Beneficial effects:

[0028] (1) The embodiment of the present invention provides a method for estimating the target signal direction of a vector hydrophone. By obtaining the combined vibration velocity according to the vibration velocity of the vector hydrophone through the guiding direction; establishing a trigonometric function equation of the target signal direction according to the combined vibration velocity; and obtaining the target signal direction according to the trigonometric function equation. It solves the problem that the existing interference suppression method of vector hydrophones can only suppress interference but cannot measure the target azimuth. While suppressing interference and improving the target signal detection ability, the estimation of the target azimuth is realized.

[0029] (2) According to the vibration velocity of the vector hydrophone, obtain the combined vibration velocity through the guiding direction, and cancel the interference part of the combined vibration velocity v c by the sound pressure, which can play a good role in suppressing interference.

[0030] (3) Adopt a numerical method to solve the trigonometric function equation, and α2 traverses the range of 0-360° with a preset step size to obtain the minimum value. The target signal direction can be obtained efficiently and accurately. Description of the Drawings

[0031] Figure 1 is the flowchart of the method for estimating the target signal direction of the vector hydrophone according to the embodiment of the present invention;

[0032] Figure 2 is the schematic diagram of the signal power spectrum in the presence of strong interference;

[0033] Figure 3 is the schematic diagram of the power spectrum after interference suppression according to the embodiment of the present invention;

[0034] Figure 4 is the schematic diagram of the estimated target direction in the presence of strong interference according to the embodiment of the present invention;

[0035] Figure 5 is the schematic diagram of the target direction estimated by the conventional method in the presence of strong interference. Detailed Embodiment

[0036] The present invention will be described in detail below with reference to the accompanying drawings and by way of examples.

[0037] An embodiment of the present invention provides a method for estimating the direction of a target signal of a vector hydrophone. Figure 1 It is a flowchart of the method for estimating the direction of a target signal of a vector hydrophone according to an embodiment of the present invention, as Figure 1 shown, including:

[0038] Step 101: Obtain a combined vibration velocity through a guiding direction according to the vibration velocity of the vector hydrophone.

[0039] Among them, obtaining the combined vibration velocity through the guiding direction according to the vibration velocity of the vector hydrophone includes: according to the components v x (n) and v y (n) of the vibration velocity in the x and y directions, by setting the guiding direction to obtain the combined vibration velocities v c and v s :

[0040]

[0041]

[0042] where n = 0,..., N - 1, and N is the length of one frame of data.

[0043] Step 102: Establish a trigonometric function equation for the direction of the target signal according to the combined vibration velocity.

[0044] Among them, establishing the trigonometric function equation for the direction of the target signal according to the combined vibration velocity includes: according to the sound pressure p(n) of the vector hydrophone, canceling the interference part of the combined vibration velocity v c to obtain the remaining signal p(n) - v c (n, α1), where α1 represents the interference direction; integrating the remaining signal and the combined vibration velocity v s to obtain the trigonometric function equation for the direction of the target signal:

[0045]

[0046] where α2 represents the direction of the target signal, and c represents the integration ratio, which is a positive number.

[0047] Step 103: Obtain the direction of the target signal according to the trigonometric function equation.

[0048] Among them, obtaining the direction of the target signal according to the trigonometric function equation includes:

[0049] Using a numerical method to solve the trigonometric function equation, when When α2 reaches the minimum value, it is the estimated direction of the target signal obtained.

[0050] Among them, a numerical method is used to solve the trigonometric equation, including: α2 traverses the range of 0-360° with a preset step size to obtain the minimum value.

[0051] The embodiment of the present invention also provides a target signal direction estimation system for a vector hydrophone, including: a vibration velocity acquisition module, configured to obtain a combined vibration velocity through a guiding direction according to the vibration velocity of the vector hydrophone; a function establishment module, configured to establish a trigonometric equation of the target signal direction according to the combined vibration velocity; a target direction acquisition module, configured to obtain the target signal direction according to the trigonometric equation.

[0052] Among them, in the vibration velocity acquisition module, according to the components v x (n) and v y (n) of the vibration velocity in the x and y directions, by setting the guiding direction to obtain the combined vibration velocities v c and v s :

[0053]

[0054]

[0055] Among them, n = 0,..., N-1, and N is the length of one frame of data.

[0056] Among them, in the function establishment module, according to the sound pressure p(n) of the vector hydrophone, the interference part of the combined vibration velocity v c is cancelled to obtain the remaining signal p(n) - v c (n, α1), where α1 represents the interference direction; the remaining signal and the combined vibration velocity v s are integrated to obtain the trigonometric equation of the target signal direction:

[0057]

[0058] Among them, α2 represents the target signal direction, and c represents the integration ratio, which is a positive number.

[0059] Among them, in the target direction acquisition module,

[0060] a numerical method is used to solve the trigonometric equation. When reaches the minimum value, α2 is the estimated target signal direction obtained.

[0061] In the embodiment of the present invention, a method for a vector hydrophone to suppress interference and estimate the signal direction is provided. In the first step, two combined vibration velocities v c and vs , and make them point to the interference direction (v c obtain the complete interference and partial signals; v s eliminates the interference and retains partial signals); in the second step, subtract the sound pressure p from v c (canceling the interference and retaining partial signals) and integrate to obtain the ratio of its integral to v s . In the third step, solve the trigonometric function equation containing the target direction to solve for the target direction. The following is a specific description of each step.

[0062] Step 1: For the vector data sound pressure p(n), vibration velocity v x (n), vibration velocity v y (n) (n = 0,..., N - 1, N, N is the length of one frame of data) received by the vector hydrophone, and set the guiding direction as Then the combined vibration velocity:

[0063]

[0064]

[0065] Assume that the directions of the interference and the target are α1 and α2 respectively, and make the guiding direction obtain v c (α1) and v s (α1) as

[0066] v c (n, α1) = v x (n)cos(α1) + v y (n)sin(α1),

[0067] v s (n, α1) = v x (n)sin(α1) - v y (n)cos(α1) (2)

[0068] The effect is to form a null in the interference direction and suppress the interference.

[0069] Step 2: Integrate to find the ratio: Subtract the sound pressure p from v c (canceling the interference and retaining partial signals) and integrate to obtain the ratio of its integral to v s .

[0070]

[0071] Step 3: Solve the trigonometric function equation.

[0072] Combine equations (1), (2) and the above integral ratio formula to obtain the trigonometric function equation:

[0073]

[0074] In the case where the interference direction α1 has been obtained, the target direction α2 can be calculated by the above trigonometric function equation. The above equation can be solved by numerical methods, that is, let α2 traverse the range of 0-360° with a certain step size. When

[0075] reaches the minimum value, α2 is the one sought. (Theoretically it is 0, but when searching with a certain step size, it is not certain that there is exactly a value that makes the equation hold. It is very likely to be very close to 0, such as 0.000000001, but not equal to 0).

[0076] The strong interference direction is generally relatively easy to obtain. For interference much stronger than the signal, the usual vector intensity method can be used to estimate the direction of the interference.

[0077] Figure 2 is a schematic diagram of the signal power spectrum in the presence of strong interference, as Figure 2 shown. In the simulation, the signal power spectrum affected by strong interference, both the signal and the interference are broadband, and a 60 Hz line spectrum is set in the signal.

[0078] Figure 3 According to the schematic diagram of the power spectrum after interference suppression according to the embodiment of the present invention, as Figure 3 shown, the signal power spectrum after suppressing the interference can be seen that the signal-to-noise ratio is significantly improved.

[0079] Figure 4 is a schematic diagram of the estimated target direction in the presence of strong interference according to the embodiment of the present invention, as Figure 4 shown. The target direction changes from 86° to -83°. When the interference direction is fixed at 150°, the estimated target direction of the present invention is basically consistent with the actual value.

[0080] Figure 5 Schematic diagram of the target direction estimated by the conventional method in the presence of strong interference, as Figure 5 shown. The target direction estimated by the conventional combined processing method of sound pressure and vibration velocity under the comparison of strong interference. It is the vector synthesis direction of the target and the interference, and is greatly affected by the interference and is very inaccurate.

[0081] In summary, the embodiments of the present invention provide a method and system for estimating the direction of a target signal of a vector hydrophone. By using various combinations of sound pressure and particle velocity, while suppressing interference, the direction of the target can be obtained by solving a trigonometric function equation, solving the problem that the current vector hydrophone beam nulling method can only detect the target in interference but cannot estimate the target azimuth. It is possible to estimate the direction of the target while suppressing low-frequency interference on a small-scale ocean monitoring platform, which can be achieved through the combined processing of the sound pressure and particle velocity of the vector hydrophone, avoiding the drawbacks of the traditional underwater acoustic array processing method that requires a large array and complex operations.

[0082] The above specific embodiments only describe the design principle of the present invention. The shapes and names of the components in this description can be different and are not limited. Therefore, those skilled in the art of the present invention can modify or equivalently replace the technical solutions recorded in the foregoing embodiments; and these modifications and replacements do not depart from the spirit and technical solutions of the present invention and should all fall within the protection scope of the present invention.

Claims

1. A method for estimating the direction of a target signal of a vector hydrophone, characterized in that, Including: Obtain the combined vibration velocity according to the vibration velocity of the vector hydrophone through the guiding direction; Establish a trigonometric function equation of the target signal direction according to the combined vibration velocity; Obtain the target signal direction according to the trigonometric function equation.

2. The method according to claim 1, characterized in that, The obtaining of the combined vibration velocity according to the vibration velocity of the vector hydrophone through the guiding direction includes: According to the components \(v_{x}(n)\) and \(v_{y}(n)\) of the vibration velocity in the x and y directions, by setting the guiding direction x \((n)\), \(v_{y}\) y (n), the combined vibration velocity \(v_{c}\) is obtained as \(v_{c}\) c and \(v_{c}\) s : where n = 0, …, N - 1, N, and N is the length of one frame of data.

3. The method according to claim 1, wherein The establishing of the trigonometric function equation of the target signal direction according to the combined vibration velocity includes: According to the sound pressure p(n) of the vector hydrophone, cancel the interfering part of the combined vibration velocity v c to obtain the remaining signal p(n) - v c (n, α1), where α1 represents the interference direction; Integrate the remaining signal and the combined vibration velocity v s to obtain a trigonometric function equation for the direction of the target signal: where α2 represents the target signal direction, and c represents the integration ratio, which is a positive number.

4. The method according to claim 3, characterized in that The obtaining of the target signal direction according to the trigonometric function equation includes: Solve the trigonometric function equation using a numerical method. When reaches the minimum value, α2 is the estimated direction of the target signal obtained.

5. The method according to claim 4, wherein The solving of the trigonometric function equation by using a numerical method includes: α2 traverses the range of 0 - 360° with a preset step size to obtain the minimum value.

6. A target signal direction estimation system for a vector hydrophone, characterized in that Including: A vibration velocity obtaining module, configured to obtain the combined vibration velocity according to the vibration velocity of the vector hydrophone through the guiding direction; A function establishing module, configured to establish a trigonometric function equation of the target signal direction according to the combined vibration velocity; A target direction obtaining module, configured to obtain the target signal direction according to the trigonometric function equation.

7. The system according to claim 6, wherein In the vibration velocity obtaining module, According to the components v x (n) and v y (n) in the x and y directions of the vibration velocity, by setting the guiding direction obtain the combined vibration velocity v c and v s : where n = 0, …, N - 1, N, and N is the length of one frame of data.

8. The system according to claim 6, wherein In the function establishing module, According to the sound pressure p(n) of the vector hydrophone, cancel the interfering part of the combined vibration velocity v c to obtain the remaining signal p(n) - v c (n, α1), where α1 represents the interference direction; Integrate the remaining signal and the combined vibration velocity v s to obtain a trigonometric function equation for the target signal direction: where α2 represents the target signal direction, and c represents the integration ratio, which is a positive number.

9. The system according to claim 6, wherein In the target direction obtaining module, Using a numerical method to solve the trigonometric function equation, when α2 at the minimum value is the estimated direction of the target signal obtained.

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