An underwater sound source positioning method and system based on a sound source array

Abstract

The present application belongs to the technical field of underwater positioning, and particularly relates to a method and system for positioning underwater sound sources based on a sound source array, which method comprises the following steps: firstly, obtaining a preliminary spatial energy spectrum through conventional beam forming; then, constructing an interference significance index combining energy value and angular deviation degree, which is used to identify the direction of strong interference sources; next, constructing an interference covariance matrix only using the identified strong interference information, and calculating adaptive weights therefrom; finally, applying the weights to weighted summation of signals, forming a deep notch in the direction of strong interference to suppress interference, so as to obtain the final echo signal for positioning. The present application can precisely suppress interference while maintaining the gain of target signals, and significantly improves the signal-to-noise ratio, accuracy and robustness of underwater positioning in a complex acoustic environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underwater positioning. More particularly, the present application relates to an underwater sound source positioning method and system based on a sound source array. BACKGROUND

[0002] In marine exploration or underwater resource mapping, phased array sound source arrays are widely used to replace traditional single-point sound sources to improve exploration efficiency; dynamic delay-and-sum beamforming (DSB) is a basic technology for implementing phased array electronic scanning.

[0003] This technology applies precise time delays to each array element in the array, causing the sound energy to be in phase and superimposed on the desired detection direction, i.e., the main lobe, while forming side lobes in other directions; by dynamically adjusting the delay, the DSB technology can achieve high-speed electronic scanning of the sound wave main lobe, covering a very wide detection swath in a single voyage, significantly improving the mapping efficiency and accuracy.

[0004] However, the existing dynamic delay-and-sum beamforming algorithm is a data-independent processor, and its beam response pattern, including the main lobe direction and side lobe structure, is determined according to fixed weight and delay calculation before transmission and remains unchanged during signal processing; this algorithm uses the same and undifferentiated spatial filtering process for signals from all directions, whether useful seabed echoes or interference noise.

[0005] Therefore, this technology has limitations: when the acoustic environment of the mapping area is complex, especially when there are strong interference sources, such as multiple strong reflections from the sea surface or seabed, acoustic device signals from adjacent other ships, or strong reflectors of the ship's own structure, the algorithm lacks active suppression capability; even if these strong interference sources are located in the side lobe direction, their strong energy may leak into the main receiving beam through the fixed side lobe structure, forming a false target, or directly drowning out the weak seabed echo signals in the main lobe direction. SUMMARY

[0006] To solve the technical problem of poor robustness of the algorithm in a complex acoustic environment caused by the data-independent processing method of the existing technology, which seriously affects the accuracy and reliability of seabed topography mapping, the present application provides solutions in the following aspects.

[0007] In a first aspect, the present application provides an underwater acoustic source positioning method based on an acoustic source array, comprising: performing conventional beamforming on the received signals of a plurality of array elements of the acoustic source array to obtain a preliminary spatial energy spectrum covering a preset scanning range; taking any scanning angle as a main lobe scanning angle, and calculating an interference significance index of each scanning angle according to the energy value corresponding to each scanning angle in the preliminary spatial energy spectrum and the angle deviation of each scanning angle from the main lobe scanning angle, the interference significance index being positively correlated with the energy value and the angle deviation; identifying the scanning angles with interference significance indexes greater than a preset significance threshold as strong interference source directions; obtaining the spatial model of each strong interference source direction according to the array steering vector corresponding to the strong interference source direction, multiplying the spatial model of each strong interference source direction by the energy corresponding to the strong interference source direction to obtain the weighted spatial model of the strong interference source direction, and then obtaining the sum of the weighted spatial models of all strong interference source directions as an interference covariance matrix; calculating a set of adaptive weights based on the interference covariance matrix and the array steering vector corresponding to the main lobe scanning angle, and performing weighted summation on the delay compensation signals of all array elements at the main lobe scanning angle by using the adaptive weights to obtain the final echo signal of the main lobe scanning angle; and obtaining the final echo signals of all scanning angles for underwater acoustic source positioning.

[0008] The present application can identify strong interference sources that threaten the main lobe detection direction by constructing an interference significance index combining energy value and angle deviation, rather than blindly processing all signals. Subsequently, the present application only uses the information of the identified strong interference sources to construct an interference covariance matrix and calculate adaptive weights, thereby forming deep nulls in the strong interference direction while maintaining the gain of the main lobe direction. The present application realizes precise active suppression of interference, effectively solves the problem of strong interference drowning target signals or forming false targets caused by sidelobe leakage in the prior art, and significantly improves the signal-to-noise ratio, accuracy and robustness of underwater acoustic source positioning in complex acoustic environments.

[0009] Preferably, the method for obtaining the preliminary spatial energy spectrum comprises: controlling the acoustic source array to emit detection sound waves and receive the original echo signals of the array elements; setting a detection scanning angle range and discretizing the detection scanning angle range according to a resolution of 0.5 degrees to obtain all discrete scanning angles; for any scanning angle: calculating the geometric time delay corresponding to the scanning angle to apply a time shift corresponding to the scanning angle to the original echo signal of each array element to obtain the delay compensation signal of each array element; averaging the delay compensation signals of all array elements to obtain the beam output time sequence signal of the scanning angle; calculating the average power of each beam output time sequence signal within an observation time window; and combining the average energies corresponding to all scanning angles to obtain the preliminary spatial energy spectrum.

[0010] The application provides data basis for subsequent interference significance index calculation by time delay compensation, summation and average power calculation of each array element signal, and ensures standardization and reliability of the preliminary energy spectrum acquisition process.

[0011] Preferably, the calculation of the average power of each beam output timing signal in the observation time window comprises: the observation time window corresponds to 256 sampling points; for the beam output timing signal of the scanning angle , ; the formula is: ; in the formula, is the average energy of the scanning angle in the observation time window; is the sampling point index in the observation time window; is the signal amplitude of the th sampling point in the beam output timing signal of the scanning angle .

[0012] Preferably, the formula for calculating the geometric time delay corresponding to the scanning angle is: ; in the formula, is the geometric time delay of the th array element at the scanning angle ; is the spatial position vector of the th array element; is a unit scanning angle vector pointing to the scanning angle ; is the underwater sound velocity.

[0013] The application ensures the accuracy of the time translation compensation of the received signals of each array element in the initial stage of beam forming by calculating the geometric time delay corresponding to the scanning angle, which is the basis for correctly in-phase superposition of sound energy at the expected scanning angle, thereby ensuring the accuracy of the preliminary spatial energy spectrum and laying a foundation for subsequent accurate identification of the direction of the interference source.

[0014] Preferably, the formula for calculating the interference significance index is: ; in the formula, is the interference significance index of the scanning angle ; is the average energy of the scanning angle in the observation time window; is an energy absolute threshold, and , is the average value of the average energy corresponding to all scanning angles in the preliminary spatial energy spectrum; is the scanning angle and the main lobe scanning angle angular deviation of the main lobe, and , represents taking an absolute value; is a hyperbolic tangent function; is a main lobe width, which is set to 5 degrees, is a transition width, which is set to 10 degrees.

[0015] The present application combines the energy intensity and the angular deviation of the main lobe, and the nonlinear hyperbolic tangent function to calculate the interference significance index, which can distinguish the useful high-energy echo located near the main lobe and the strong interference signal located in the side lobe direction, effectively avoids misjudging the target signal as interference or incorrectly suppressing the signal in the main lobe, and greatly improves the accuracy of interference identification.

[0016] Preferably, the method for obtaining the array steering vector corresponding to each strong interference source direction is: for the identified first strong interference source direction , the corresponding array steering vector is calculated, the array steering vector is a complex vector, the first element of which is , wherein, is an imaginary unit, is the center angular frequency of the signal, and , is the center frequency of the detection sound pulse, and is a known parameter; is the geometric time delay of the first array element in the direction .

[0017] The present application defines the method for obtaining the array steering vector, which is defined as a complex vector based on the geometric time delay of each array element and the center frequency of the signal, and gives each strong interference source direction a unique spatial fingerprint, which is a key step for subsequent construction of a covariance matrix that can reflect the spatial characteristics of interference, and ensures the accuracy of subsequent adaptive processing.

[0018] Preferably, the method for calculating the spatial model of the strong interference source direction is: multiplying the array steering vector corresponding to the strong interference source direction with the conjugate transpose of itself.

[0019] Preferably, before calculating the adaptive weight, it further includes: performing diagonal loading processing on the interference covariance matrix to obtain a modified interference covariance matrix , wherein, is an identity matrix, is equal to times the average value of all elements on the diagonal of .

[0020] Preferably, the calculation formula of the adaptive weight is: ; in the formula, is the adaptive weight vector of ; is the inverse matrix of the corrected interference covariance matrix; is the array steering vector of the main lobe scanning angle ; denotes the conjugate transpose.

[0021] The present application can ensure that the signal in the target direction does not produce distortion while minimizing the interference and noise output power; this ensures that the finally formed beam pattern can form the deepest null on all identified strong interference directions, thereby achieving the maximum suppression of interference and achieving the optimal interference suppression effect.

[0022] In a second aspect, the present application provides an underwater sound source positioning system based on a sound source array, comprising a processor and a memory, the memory storing computer program instructions which, when executed by the processor, implement the above-mentioned underwater sound source positioning method based on a sound source array.

[0023] By adopting the above technical solution, the above-mentioned underwater sound source positioning method based on a sound source array is generated into a computer program and stored in the memory to be loaded and executed by the processor, so that a terminal device is made according to the memory and the processor, and convenient use is achieved.

[0024] The present application has the following beneficial effects:

[0025] The present application can identify the strong interference source that threatens the main lobe detection direction by constructing an interference significance index combining the energy value and the angle deviation degree, rather than blindly processing all signals; subsequently, the present application only uses the identified strong interference source information to construct the interference covariance matrix and calculates the adaptive weight, thereby forming a deep null in the strong interference direction while maintaining the main lobe direction gain; the present application realizes accurate active suppression of interference, effectively solves the problem of strong interference drowning the target signal or forming a false target caused by the sidelobe leakage in the prior art, and significantly improves the signal-to-noise ratio, accuracy and robustness of underwater sound source positioning in a complex acoustic environment. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a flowchart schematically showing an underwater sound source positioning method based on a sound source array in the present application;

[0027] Figure 2 is a schematic diagram schematically showing a preliminary spatial energy spectrum obtained by conventional beam forming;

[0028] Figure 3 is a schematic diagram illustrating the interference significance index of each scanning angle;

[0029] Figure 4 is a schematic diagram illustrating the heat map corresponding to the interference covariance matrix;

[0030] Figure 5 is a comparison diagram of the preliminary spatial energy spectrum obtained by conventional beamforming and the spatial energy spectrum with strong interference suppressed. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0032] The specific embodiments of the present application will be described in detail below with reference to the drawings.

[0033] The embodiments of the present application disclose an underwater sound source positioning method based on a sound source array, referring to Figure 1 , comprising steps S1-S4:

[0034] S1: performing conventional beamforming on the received signals of a plurality of array elements of the sound source array to obtain a preliminary spatial energy spectrum covering a preset scanning range.

[0035] When the phased array sonar performs exploration, a sound wave pulse is actively transmitted, and then the receiving mode is switched to listen to the sound wave signals reflected back by the sea bottom, interference, etc.

[0036] First, the central controller on the exploration ship triggers a large sound source array, which serves as a transmitting array to transmit a detection sound pulse of a specific waveform to the underwater, the specific waveform being an LFM linear frequency modulation signal; in the silent receiving window after transmission, the synchronization of the receiving array elements in the array starts to collect the returned acoustic pressure signals, and the receiving array elements are hydrophones.

[0037] Further, the analog signals collected by each array element are amplified, filtered and analog-digital converted to obtain parallel original echo signal time series data , wherein, is the array element index, ; the parallel time series data are combined to obtain the original signal vector of this operation , wherein, represents matrix transposition.

[0038] Then, based on the survey mission requirements and array performance, a detection scanning angle range covering the total seabed rafting area is set, denoted as . In this embodiment, the detection scanning angle ranges from -70 degrees to +70 degrees, that is... =-70 degrees, =70 degrees; This will expand the detection scanning angle range. Discretize the data at a resolution of 0.5 degrees to obtain all discrete scanning angles.

[0039] Furthermore, for any scanning angle Calculate the first The geometric time delay of each element relative to the array reference center, i.e., the origin, is as follows: The specific calculation formula is as follows:

[0040]

[0041] In the formula, For the first Individual elements at scanning angle Geometric time delay; For the first The spatial position vector of each array element is an inherent physical parameter of the array, which is known after the array is designed and manufactured. It refers to the scanning angle. The unit scan angle vector; This is the underwater speed of sound, and its value can be measured in real time using a temperature, salinity, and depth gauge carried by the exploration vessel.

[0042] Furthermore, according to the first Individual elements at scanning angle Geometric time delay , for the Individual elements The original echo signal received at any time Apply time shift to obtain the first Delay compensation signal for each array element The scanning angle is obtained by averaging the delay compensation signals of all array elements. The conventional DSB beam output timing signal on This allows us to obtain time-series signals representing the echo intensity at different spatial scanning angles, which form the direct data basis for subsequent calculations of the spatial energy spectrum.

[0043] It should be noted that the generated timing signal The echo of energy at different distances is included in the time series data. In order to identify the total energy of the interference source at a certain direction, the energy of the signal in a time window needs to be averaged, so as to obtain an energy distribution which only varies with the scanning angle, i.e. the spatial energy spectrum.

[0044] Specifically, an observation time window for energy calculation is set, which corresponds to consecutive sampling points in the received time series data. In order to identify the interference in real time, a shorter is preferred. Therefore, the observation time window is set to be 256 sampling points; for the conventional DSB beam output time series signal at a scanning angle , the average energy of the signal in the observation time window is calculated, which is . The specific calculation formula is:

[0045]

[0046] In the formula, E (θ) represents the average energy of the beam output time series signal at the scanning angle θ in the observation time window; n represents the sampling point index in the observation time window; s (n, θ) represents the signal amplitude of the n-th sampling point in the beam output time series signal at the scanning angle θ; and |s (n, θ)|2 represents the square of the signal amplitude, representing the instantaneous power.

[0047] Finally, all the average energies corresponding to the scanning angles are combined to obtain the preliminary spatial energy spectrum.

[0048] It should be noted that the preliminary spatial energy spectrum generated in this step is the direct input for identifying the strong interference source in the subsequent steps, which quantifies the energy intensity from different spatial scanning angles, so that the subsequent steps can construct the interference significance index by analyzing the peak value, mean value and other characteristics of the spectrum.

[0049] S2: Taking any scanning angle as the main lobe scanning angle, the interference significance index of each scanning angle is calculated according to the energy value corresponding to each scanning angle in the preliminary spatial energy spectrum and the angle deviation of each scanning angle from the main lobe scanning angle, which is used to identify the direction of the strong interference source.

[0050] It should be noted that the peak value in the preliminary spatial energy spectrum may come from useful seabed echoes or strong interference: the useful seabed echoes are usually located near the main lobe scanning angle , while the energy of the strong interference, such as sea surface reflection or noise from other ships, may be extremely high, and its direction ​​​​​​​​Possible deviation from the current main lobe scanning angle ; therefore, constructing an index combining energy amplitude and spatial position deviation can more accurately identify the strong interference source that needs to be suppressed.

[0051] Take any one scanning angle as the main lobe scanning angle , and the subsequent steps S2 to S4 are all analyses on the main lobe scanning angle .

[0052] First, calculate the mean value of the average energy corresponding to all scanning angles in the preliminary spatial energy spectrum as the global average energy , and then set the energy absolute threshold .

[0053] Further, for any scanning angle , calculate its energy amplitude and the angle deviation from the main lobe scanning angle , and calculate the interference significance index of the scanning angle , and the specific calculation formula is:

[0054]

[0055] In the formula, is the interference significance index of the scanning angle ; E is the average energy of the scanning angle in the observation time window; is the energy absolute threshold; is the angle deviation of the scanning angle from the main lobe scanning angle , and , represents taking the absolute value; is the hyperbolic tangent function; is the main lobe width, set to 5 degrees, is the transition width, set to 10 degrees; is a non-decreasing function that increases with the angle deviation , used to enhance the significance of strong signals deviating from the main lobe scanning angle.

[0056] Among them, the hyperbolic tangent function is used for nonlinear mapping of the angle deviation, aiming to achieve smooth transition weighting in the main lobe and outside the main lobe; specifically, when , that is, the angle deviation is within the main lobe width, the output is close to 0, and the energy is not additionally enhanced; when ​When the output approaches 1, the significance of the high-energy signal is close to its original energy ratio; while... arrive Within the transition region, the function value smoothly rises from 0 to 1, avoiding orientation recognition jumps or misjudgments caused by hard thresholds, balancing main lobe protection and interference sensitivity enhancement, and improving the robustness of interference recognition.

[0057] Finally, set the threshold for the significance of interference. For all scanning angles Disturbance significance index Make a judgment and determine all those that satisfy the condition. scanning angle Identify the locations of strong interference sources and use this information to obtain the locations of all strong interference sources.

[0058] It should be noted that by constructing an interference significance index, this step can automatically filter out strong interference signals that have both high energy and deviate from the current detection main lobe from the complex sound field, realizing intelligent identification and precise positioning of interference sources, avoiding misjudging useful target echoes as interference, and preventing incorrect suppression of signals within the main lobe.

[0059] S3: Based on the array steering vector corresponding to the azimuth of each strong interference source, obtain its spatial model, combine it with its corresponding energy to obtain the weighted spatial model of the azimuth of each strong interference source, and obtain the interference covariance matrix in combination.

[0060] It should be noted that in order to accurately form nulls at the scanning angle of the interference sources when calculating the adaptive weights in the subsequent process, a feature is needed to describe the spatial characteristics of these interference sources on the array.

[0061] First, for the identified first Location of strong interference source Calculate its corresponding array steering vector The array guide vector is a A complex vector, whose ... The elements are ,in, The imaginary unit, Let be the center angular frequency of the signal, and , It detects the center frequency of the acoustic pulse, which is a known parameter; It is the first Each element is in this direction Geometric time delay.

[0062] Among them, array guide vector Describes a source A plane wave in the direction of the wave arrives at... The phase relationship presented by different array elements is due to the different positions of each element and the different arrival times of the sound waves, thus producing a phase difference. The phase difference vector in dimension 1 is the spatial fingerprint in that direction.

[0063] Meanwhile, regarding the main lobe scanning angle Calculate the main lobe scanning angle The array guide vector.

[0064] Furthermore, according to the first Location of strong interference source Array guide vector Calculate the first Spatial model of the orientation of a strong interference source ,in, This indicates the conjugate transpose. this A vector and its conjugate transpose Vector multiplication results in a... The matrix completely describes the spatial structure of the orientation of strong interference sources.

[0065] Furthermore, multiply the spatial model by its corresponding energy. , obtained the A weighted spatial model of the orientations of strong interference sources yields the total interference covariance matrix. It equals the sum of the weighted spatial models of the orientations of all strong interference sources.

[0066] Meanwhile, to ensure the stability of matrix inversion, the interference covariance matrix is... Diagonal loading is performed to obtain the corrected interference covariance matrix. ,in, It is the identity matrix. It is a very small positive number. In this embodiment, equal The average of all elements on the diagonal The multiple is used to prevent matrix singularities.

[0067] It should be noted that the interference covariance matrix constructed in this step The spatial characteristics of the main strong interferences in the sound field are accurately modeled. It does not include the target signal or diffuse background noise, so that the subsequent adaptive weight calculation is optimized only for these specific interferences, which greatly improves the pertinence and robustness of interference suppression.

[0068] S4: Based on the interference covariance matrix and the array steering vector corresponding to the main lobe scanning angle, a set of adaptive weights is calculated, and the delay compensation signals of all array elements at the main lobe scanning angle are weighted and summed to obtain the final echo signal at the main lobe scanning angle, so as to obtain the final echo signals at all scanning angles for underwater sound source positioning.

[0069] It should be noted that the interference covariance matrix is obtained , and the further goal is to find a new set of array element weights , which must satisfy two conditions: one is to maintain high gain at the expected main lobe scanning angle to ensure that the target echo is not lost; the other is to form as deep a null as possible or as low a sidelobe as possible at the azimuths of all identified strong interference sources , so as to suppress interference energy; this is a constrained optimization problem, that is, to minimize the total output power from the interference scanning angle while maintaining the gain of the target scanning angle unchanged.

[0070] Therefore, according to the interference covariance matrix and the array steering vector at the main lobe scanning angle , the adaptive weight vector is calculated, and the specific calculation formula is:

[0071]

[0072] In the formula, is the adaptive weight vector of ; is the inverse matrix of the corrected interference covariance matrix; is the array steering vector at the main lobe scanning angle ; and denotes conjugate transpose.

[0073] Among them, the denominator is a scalar, which is used to normalize the weights to ensure that the gain at the scanning angle is 1 to achieve distortionless response.

[0074] It should be noted that the adaptive weight vector calculated in this step is data-dependent, which is dynamically adjusted according to the real-time identified interference sources. The beam pattern formed by using this set of weights will automatically produce deep nulls at all identified strong interference azimuths while keeping the main lobe scanning angle unchanged, thereby physically shielding the leakage of strong interference signals.

[0075] Further, the adaptive weight vector in the main lobe scanning angle weight, the delay compensation signals of the array elements in the main lobe scanning angle are weighted and summed to obtain the final echo signal of the main lobe scanning angle which suppresses the strong interference.

[0076] Further, for each scanning angle, through steps S2 to S4, its final echo signal is obtained, which is used for subsequent seabed topography solving, geomorphology analysis or underwater mineral resource identification processing, etc. underwater sound source positioning.

[0077] Exemplarily, when the main lobe scanning angle is 10°:

[0078] (1) Figure 2 is a schematic diagram of the preliminary spatial energy spectrum obtained by conventional beamforming, wherein the spectrum is dominated by an extremely strong signal located at-40°, and the normalized energy reaches the highest peak in the whole field; and there is a significantly weaker secondary peak near the main lobe scanning angle, i.e. 10°; therefore, in the preliminary spatial energy spectrum obtained by conventional beamforming, a strong interference source located at-40° suppresses the weak target signal located at the main lobe scanning angle; if the preliminary spatial energy spectrum obtained by conventional beamforming is used for underwater sound source positioning, the system will incorrectly identify the strong interference at-40° as the main target, and cannot locate the real target at the main lobe scanning angle.

[0079] (2) Figure 3 is a schematic diagram of the interference significance index of each scanning angle, wherein since there is a non-decreasing function in the calculation formula of the interference significance index, which increases with the angle deviation , the significance of the strong signal deviating from the main lobe scanning angle can be improved, therefore, at the-40° position, the interference significance index is obviously higher than the threshold value 0.5, and near the main lobe scanning angle, the interference significance index is close to 0, thereby successfully diagnosing the strong signal at-40° as the position of the strong interference source that needs to be removed.

[0080] (3) Figure 4 is a schematic diagram of the heat map corresponding to the interference covariance matrix, wherein since the number of array elements =10, the size of the heat map corresponding to the interference covariance matrix is 10x10.

[0081] (4) Figure 5 ​The contrast chart of the preliminary spatial energy spectrum obtained by the conventional beam forming and the spatial energy spectrum with the strong interference suppressed; wherein, in the preliminary spatial energy spectrum obtained by the conventional beam forming, the main lobe scanning angle is as a weak target, which is submerged by the strong interference; in the obtained spatial energy spectrum with the strong interference suppressed, firstly, the strong interference is accurately suppressed, and a V-shaped null appears at-40°, the energy at-40° is suppressed, and since the strong interference at-40° is eliminated, the originally submerged main lobe scanning angle signal can now be shown, and becomes a new highest energy peak, which indicates that the adaptive weight successfully produces a deep null in the direction of the strong interference, greatly suppresses the energy from the direction, and pulls the main lobe scanning angle from the noise to become a new strongest signal.

[0082] It should be noted that since the strong interference energy is suppressed by the null in the adaptive weight vector The weak seabed echo that may be originally submerged can be shown, and the false target is eliminated, so that the signal-to-noise ratio of the final echo signal output by the step is significantly improved compared with the echo signal output by the conventional DSB, and the robustness and accuracy of seabed mapping in a complex acoustic environment are ensured.

[0083] The embodiment of the present application further discloses an underwater sound source positioning system based on a sound source array, comprising a processor and a memory, the memory stores computer program instructions, and when the computer program instructions are executed by the processor, a kind of underwater sound source positioning method based on sound source array according to the present application is realized.

[0084] The above system further includes communication bus and communication interface and other components well known to those skilled in the art, the setting and function thereof are known in the art, thus not repeated here.

Claims

1. A method for underwater sound source localization based on a sound source array, characterized in that, include: Conventional beamforming is performed on the received signals of multiple elements of the sound source array to obtain a preliminary spatial energy spectrum covering a preset scanning range; Using any scanning angle as the main lobe scanning angle, and based on the energy value corresponding to each scanning angle in the preliminary spatial energy spectrum, as well as the angular deviation between each scanning angle and the main lobe scanning angle, the interference significance index of each scanning angle is calculated. The interference significance index is positively correlated with both the energy value and the angular deviation. Scanning angles with interference significance indices greater than a preset significance threshold are identified as strong interference source locations. Based on the array steering vector corresponding to the azimuth of each strong interference source, its spatial model is obtained. Multiply the spatial model of the azimuth of each strong interference source by its corresponding energy to obtain the weighted spatial model of the azimuth of each strong interference source. Then the interference covariance matrix is ​​equal to the sum of the weighted spatial models of all strong interference source azimuths. Based on the interference covariance matrix and the array steering vector corresponding to the main lobe scanning angle, a set of adaptive weights is calculated, and the delay compensation signals of all array elements at the main lobe scanning angle are weighted and summed to obtain the final echo signal at the main lobe scanning angle. The final echo signals from all scanning angles are obtained for underwater sound source localization.

2. The underwater sound source localization method based on a sound source array according to claim 1, characterized in that, The method for obtaining the preliminary spatial energy spectrum includes: Control the sound source array to emit detection sound waves and receive the original echo signals from each array element; Set the detection scanning angle range and discretize it with a resolution of 0.5 degrees to obtain all discrete scanning angles; For any scanning angle: calculate the geometric time delay corresponding to the scanning angle, which is used to apply the application time shift corresponding to each scanning angle to the original echo signal of each array element, and obtain the delay compensation signal of each array element; average the delay compensation signals of all array elements to obtain the beam output timing signal of the scanning angle; calculate the average energy of each beam output timing signal within the observation time window. By combining the average energies corresponding to all scanning angles, a preliminary spatial energy spectrum is obtained.

3. The underwater sound source localization method based on a sound source array according to claim 2, characterized in that, The calculation of the average energy of the output timing signal of each beam within the observation time window includes: The observation time window corresponds to the beam output timing signal in A number of consecutive sampling points are set. There are 256 sampling points; For scanning angle Beam output timing signal: ； In the formula, For scanning angle Average energy within the observation time window; Index of sampling points within the observation time window; For scanning angle In the beam output timing signal, the first The signal amplitude at each sampling point.

4. The underwater sound source localization method based on a sound source array according to claim 2, characterized in that, The formula for calculating the geometric time delay corresponding to the scanning angle is: ； In the formula, For the first Individual elements at scanning angle Geometric time delay; For the first The spatial position vectors of each array element; It refers to the scanning angle. The unit scan angle vector; This refers to the speed of sound underwater.

5. The underwater sound source localization method based on a sound source array according to claim 3, characterized in that, The formula for calculating the significance index of the interference is: ； In the formula, For scanning angle The significance index of interference; For scanning angle Average energy within the observation time window; It is the absolute energy threshold, and , This is the mean of the average energy corresponding to all scanning angles in the preliminary spatial energy spectrum; For scanning angle With the main lobe scanning angle Angular deviation, and , Indicates taking the absolute value; It is the hyperbolic tangent function; The main lobe width is set to 5 degrees. The transition width is set to 10 degrees.

6. The underwater sound source localization method based on a sound source array according to claim 4, characterized in that, The method for obtaining the array steering vector corresponding to the azimuth of each strong interference source is as follows: For the identified first Location of strong interference source Calculate its corresponding array steering vector The array guide vector is a A complex vector, whose ... The elements are ,in, The imaginary unit, Let be the center angular frequency of the signal, and , It detects the center frequency of the acoustic pulse, which is a known parameter; It is the first Each element is in this direction Geometric time delay.

7. The underwater sound source localization method based on a sound source array according to claim 1, characterized in that, The calculation method for the spatial model of the strong interference source orientation is as follows: multiply the array steering vector corresponding to the strong interference source orientation by its own conjugate transpose.

8. The underwater sound source localization method based on a sound source array according to claim 1, characterized in that, Before calculating the adaptive weights, the method further includes: performing a diagonal loading process on the interference covariance matrix to obtain a corrected interference covariance matrix. ,in, It is the identity matrix. equal The average of all elements on the diagonal times.

9. The underwater sound source localization method based on a sound source array according to claim 8, characterized in that, The formula for calculating the adaptive weights is: ； In the formula, for Adaptive weight vector; This is the inverse of the corrected interference covariance matrix; Main lobe scanning angle Array guide vector; This indicates the conjugate transpose.

10. An underwater sound source localization system based on a sound source array, characterized in that, include: A processor and a memory, wherein the memory stores computer program instructions that, when executed by the processor, implement an underwater sound source localization method based on a sound source array according to any one of claims 1-9.

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