A passive acoustic positioning fusion method, system, device and medium for underwater small platform detection

Abstract

The present application relates to a kind of passive acoustic positioning fusion method, system, equipment and medium for underwater small platform detection, its method includes: receiving the mixed signal observed by each hydrophone and obtaining source signal from mixed signal;Establish double five-element acoustic positioning array model, according to source signal and the coordinate position of each hydrophone, the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array are calculated respectively;According to the installation error of introduced array shape, the sound speed error and the time delay estimation error, the distance error, the azimuth error and the pitch angle error of sound source coordinates are obtained;Based on the distance error, the azimuth error and the pitch angle error of sound source positioning, set weight coefficient, according to weight coefficient, the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array are fused, then output sound source coordinates.The present application provides more accurate and reliable sound source positioning means for underwater small platform detection, has important significance to marine detection, geological survey and military application and other fields.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of underwater acoustic positioning technology, and particularly relates to a passive acoustic positioning fusion method, system, device and medium for underwater small platform detection. BACKGROUND

[0002] Underwater acoustic positioning technology has been widely used in military, geological exploration and ocean exploration, etc. According to the baseline length of the transponder, the existing underwater acoustic positioning technology can be mainly divided into long baseline, short baseline and ultra-short baseline. However, these technologies generally face a challenge in the application process, that is, the interference of noise. This interference is mainly caused by the noise mixed in the target sound source collection process, which can significantly reduce the accuracy of the positioning result. Due to this problem, how to improve the positioning accuracy and stability has become the focus of current underwater acoustic positioning technology research.

[0003] On the other hand, underwater small platforms are increasingly widely used in ocean monitoring and military fields due to their small size, flexible deployment and low cost. These small platforms are usually composed of sensors, actuators, energy supply systems, communication devices and other parts, and can perform large-scale and diversified data collection, providing strong support for related field research. Especially in the detection technology, underwater small platforms mainly rely on their carried passive sonar equipment for underwater target detection and identification. However, due to the limited space of the small platform, specific requirements are put forward for the size and complexity of the detection equipment. In actual application, these detection equipment also face the problem of noise interference, which affects the accuracy and efficiency of detection to some extent.

[0004] Therefore, the existing underwater acoustic positioning technology still faces the problems of noise interference, insufficient positioning accuracy and stability in actual application, especially on the underwater small platform with limited space, these problems are more prominent. SUMMARY

[0005] (I) Technical problems to be solved

[0006] In view of the above shortcomings and deficiencies of the prior art, the present application provides a passive acoustic positioning fusion method, system, device and medium for underwater small platform detection, which solves the technical problems of noise interference, insufficient positioning accuracy and stability of underwater acoustic positioning technology in actual application.

[0007] (II) Technical solutions

[0008] In order to achieve the above purpose, the main technical solutions adopted by the present application include:

[0009] In a first aspect, an embodiment of the present application provides a passive acoustic positioning fusion method for underwater small platform detection, comprising: receiving mixed signals observed by each hydrophone on the underwater small platform, and obtaining source signals from the mixed signals by using a preset ICA model and power spectrum entropy; establishing a dual five-element acoustic positioning array model of the underwater small platform composed of multiple hydrophones, and calculating acoustic source coordinates in an upper five-element stereo array and a lower five-element stereo array in the dual five-element acoustic positioning array model according to the source signals and coordinate positions of the hydrophones; according to introduced array shape installation errors, sound speed errors and time delay estimation errors, distance errors, azimuth angle errors and pitch angle errors of the acoustic source coordinates are obtained through error analysis; based on the distance errors, the azimuth angle errors and the pitch angle errors of the acoustic source positioning, corresponding weight coefficients are set, the acoustic source coordinates in the upper five-element stereo array and the lower five-element stereo array are fused according to the weight coefficients, and then the fused acoustic source coordinates are output.

[0010] Optionally, receiving mixed signals observed by each hydrophone on the underwater small platform, and obtaining source signals from the mixed signals by using a preset ICA model and power spectrum entropy comprises: receiving mixed signals observed by each hydrophone on the underwater small platform, and confirming that the source signals and noise signals are statistically independent; using a mixed matrix A pre-constructed in the ICA model, separating the true source signals S from the observed signals X through a first conversion formula X = AS; finding an inverse transformation matrix W through Newton iteration method, and obtaining simulated source signals Y close to the true source signals S based on the inverse transformation matrix W and a second conversion formula Y = WX; performing discrete Fourier transform on the simulated source signals Y to obtain power spectrum density estimation, and performing normalization processing on the power spectrum to ensure that the sum of each frequency component is 1; calculating information entropy according to the normalized power spectrum to obtain power spectrum entropy; and judging noise components in each frequency band of the simulated source signals Y according to a set threshold and the power spectrum entropy, and outputting the source signals after removing the determined noise components.

[0011] Optionally, establishing a dual five-element acoustic positioning array model of the underwater small platform composed of multiple hydrophones, and calculating acoustic source coordinates in an upper five-element stereo array and a lower five-element stereo array in the dual five-element acoustic positioning array model according to the source signals and coordinate positions of the hydrophones comprises: establishing a dual five-element acoustic positioning array model of the underwater small platform composed of six hydrophones; determining the coordinate positions of each hydrophone in a Cartesian three-dimensional rectangular coordinate system, the coordinates of the acoustic source in the three-dimensional rectangular coordinate system, and the sound wave propagation time delay values of the acoustic source to each hydrophone; for the upper five-element stereo array, the source signals, the coordinate positions of the hydrophones and the coordinate positions of the acoustic source are used to calculate the acoustic source coordinates in the upper five-element stereo array through a time delay estimation positioning algorithm; for the lower five-element stereo array, the source signals, the coordinate positions of the hydrophones and the coordinate positions of the acoustic source are used to calculate the acoustic source coordinates in the lower five-element stereo array through the time delay estimation positioning algorithm.

[0012] Among them, the six hydrophones are configured into an upper five-element stereo array and a lower five-element stereo array. The upper five-element stereo array is composed of five selected hydrophones, forming a specific spatial geometric relationship, which is used to receive and process signals emitted by underwater sound sources to determine the positioning information of the sound sources in the upper five-element stereo array. The hydrophones formed in the lower five-element stereo array contain at least one hydrophone that does not exist in the upper five-element stereo array, forming another specific spatial geometric relationship, which is used to receive and process signals emitted by underwater sound sources to determine the positioning information of the sound sources in the lower five-element stereo array.

[0013] Optionally, for the upper five-element stereo array, the coordinates of the sound source in the upper five-element stereo array are calculated using the obtained source signal, the coordinate position of the hydrophone, and the coordinate position of the sound source through a time delay estimation positioning algorithm, including: for the upper five-element stereo array including the first hydrophone M1, the second hydrophone M2, the third hydrophone M3, the fourth hydrophone M4, and the fifth hydrophone M5, a reference hydrophone is set, and the time delay values ​​of the other hydrophones relative to the reference hydrophone are determined; the acoustic path difference of each hydrophone is calculated using the time delay value and sound speed from the sound source to the first hydrophone M1, the second hydrophone M2, the third hydrophone M3, the fourth hydrophone M4, and the fifth hydrophone M5; the distance difference information from the sound source to the fifth hydrophone M5 is obtained based on the coordinate position of the fifth hydrophone M5 and the coordinate position of the sound source; and the positioning relationship formula of the upper five-element stereo array in the rectangular coordinates is obtained by combining the rectangular coordinates of the sound source and the acoustic path differences of each hydrophone using a geometric relationship; according to the set condition R1>>d i1 , the acoustic path difference of each hydrophone, the conversion formula between the spherical coordinates and the rectangular coordinate system obtained from the rectangular coordinates and the spherical coordinates of the sound source, and the positioning relationship formula under the rectangular coordinates of the upper five-element three-dimensional array, to obtain the conversion relationship formula under the rectangular coordinates of the upper five-element three-dimensional array; substituting the conversion relationship formula under the rectangular coordinates of the upper five-element three-dimensional array into the spherical coordinates of the sound source coordinates to obtain the spherical coordinates of the sound source in the upper five-element three-dimensional array;

[0014] in,

[0015] The acoustic path difference of each hydrophone is:

[0016]

[0017] Where c represents the speed of sound in water, τ ij , i, j = 1, 2, 3, 4, 5, 6 represent the time delay from the sound source to the i-th hydrophone;

[0018] The rectangular coordinates of the sound source are: S(x,y,z);

[0019] The spherical coordinates of the sound source are

[0020] The positioning relationship of the upper five-element three-dimensional array in rectangular coordinates is:

[0021]

[0022] where D represents the distance from the hydrophone to the origin of the coordinate system, R i , i = 1, 2, 3, 4, 5, 6 represents the distance from the sound source to the i-th hydrophone;

[0023] The conversion formula of the spherical coordinate and the rectangular coordinate system is:

[0024]

[0025] The conversion relationship formula of the upper five-element stereo array in the rectangular coordinate is:

[0026]

[0027] The spherical coordinate of the sound source in the upper five-element stereo array is:

[0028]

[0029] where θ i , i = 1, 2, 3, 4, 5, 6 represents the azimuth angle of the sound source to the i-th hydrophone, represents the pitch angle of the sound source to the i-th hydrophone.

[0030] Alternatively, for the lower five-element stereo array, the obtained source signal, the coordinate position of the hydrophone and the coordinate position of the sound source are used to calculate the coordinate of the sound source in the lower five-element stereo array by a time delay estimation positioning algorithm, including: for the lower five-element stereo array comprising the first hydrophone M1, the second hydrophone M2, the fourth hydrophone M4 and the sixth hydrophone M6, a reference hydrophone is set, and the time delay values of the other hydrophones relative to the reference hydrophone are determined; the sound path differences of the hydrophones are calculated using the time delay values of the sound source to the first hydrophone M1, the second hydrophone M2, the third hydrophone M3, the fourth hydrophone M4 and the sixth hydrophone M6 and the sound speed; the distance difference information of the sound source to the sixth hydrophone M6 is obtained according to the coordinate position of the sixth hydrophone M6 and the coordinate position of the sound source, and the positioning relationship formula of the lower five-element stereo array in the rectangular coordinate is obtained by combining the rectangular coordinate of the sound source and the sound path differences of the hydrophones and using the geometric relationship; according to the set condition R1>>d i1 , the sound path differences of the hydrophones, the conversion formula of the spherical coordinate and the rectangular coordinate system and the positioning relationship of the lower five-element stereo array in the rectangular coordinate, the conversion relationship formula of the lower five-element stereo array in the rectangular coordinate is obtained; the conversion relationship formula of the lower five-element stereo array in the rectangular coordinate is substituted into the spherical coordinate of the sound source coordinate to obtain the spherical coordinate of the sound source in the lower five-element stereo array;

[0031] wherein,

[0032] The sound path differences of the hydrophones are:

[0033] d ij = c · τ ij ;

[0034] wherein c represents the sound speed in water, τ ij , i, j = 1, 2, 3, 4, 5, 6 represent the time delay value from the sound source to a certain hydrophone;

[0035] The rectangular coordinates of the sound source are: S(x, y, z);

[0036] The spherical coordinates of the sound source are

[0037] The positioning relationship formula of the five-element stereophonic array in rectangular coordinates is:

[0038]

[0039] wherein D represents the distance from the hydrophone to the origin of the coordinate system, R i , i = 1, 2, 3, 4, 5, 6 represent the distance from the sound source to a certain hydrophone;

[0040] The conversion formula of the spherical coordinates and the rectangular coordinates is:

[0041]

[0042] The conversion relationship formula of the five-element stereophonic array in rectangular coordinates is:

[0043]

[0044] The spherical coordinates of the sound source in the five-element stereophonic array are:

[0045]

[0046] wherein θ i , i = 1, 2, 3, 4, 5, 6 represent the azimuth angle of the sound source to the i-th hydrophone, , i = 1, 2, 3, 4, 5, 6 represent the pitch angle of the sound source to the i-th hydrophone.

[0047] Alternatively, according to the introduced array installation error, sound speed error and time delay estimation error, the distance error, azimuth angle error and pitch angle error of the sound source coordinates are obtained by error analysis, including:

[0048] The partial derivatives of the distance, azimuth angle and pitch angle of the sound source coordinates are calculated, and the array installation error, sound speed error and time delay estimation error are introduced into the partial derivatives to obtain the mathematical expressions of the distance error, azimuth angle error and pitch angle error;

[0049] Based on the mathematical expressions of the distance error, the azimuth error and the elevation error, the distance error, the azimuth error and the elevation error of the sound source coordinates are obtained through error analysis;

[0050] wherein,

[0051] The distance error is:

[0052]

[0053] The azimuth error is:

[0054]

[0055] The elevation error is:

[0056]

[0057] In the formula, σ D is the array installation error, σ C is the sound speed error, is the time delay estimation error.

[0058] Optionally, the corresponding weight coefficients are set based on the distance error, the azimuth error and the elevation error of the sound source positioning, the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array are fused according to the weight coefficients, and then the sound source coordinates after the fusion processing are output, including: determining the distance error, the azimuth error and the elevation error generated in the sound source positioning process; according to the least square method, the reciprocal of the square of the corresponding error is weighted to obtain the weight coefficients corresponding to the distance error, the azimuth error and the elevation error; the sound source coordinates obtained in the upper five-element stereo array and the lower five-element stereo array are weighted and processed respectively by using the weight coefficients; the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array after the weighted processing are fused; and the sound source coordinates after the fusion processing are output;

[0059] wherein,

[0060] The weight coefficients are:

[0061]

[0062] In the formula, k R1 , k θ1 , are respectively the weight coefficients corresponding to the distance error, the azimuth error and the elevation error of the upper five-element stereo array, k R2 , k θ2 , are respectively the weight coefficients corresponding to the distance error, the azimuth error and the elevation error of the lower five-element stereo array, σ R1 , σ θ1 , respectively are distance error, azimuth error and elevation error of the upper five-element stereo array, and R2 , respectively are distance error, azimuth error and elevation error of the lower five-element stereo array. θ2 、 respectively are distance error, azimuth error and elevation error of the lower five-element stereo array.

[0063] The sound source coordinates after fusion processing are:

[0064]

[0065] In a second aspect, the embodiment of the present application provides a passive acoustic positioning fusion system for underwater small platform detection, comprising: a source signal acquisition module, configured to receive mixed signals observed by each hydrophone on the underwater small platform, and obtain source signals from the mixed signals by using a preset ICA model and power spectrum entropy; a sound source coordinate solving module, configured to establish an underwater small platform double five-element acoustic positioning array model composed of multiple hydrophones, and calculate sound source coordinates in an upper five-element stereo array and a lower five-element stereo array in the double five-element acoustic positioning array model according to the source signals and the coordinate positions of the hydrophones; an error term introduction module, configured to obtain distance error, azimuth error and elevation error of the sound source coordinates by error analysis according to introduced array shape installation error, sound speed error and time delay estimation error; and a fusion processing module, configured to set corresponding weight coefficients based on the distance error, the azimuth error and the elevation error of the sound source positioning, fuse the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array according to the weight coefficients, and then output the sound source coordinates after fusion processing.

[0066] In a third aspect, the embodiment of the present application provides an underwater small platform sound source positioning system, comprising: an underwater small platform, equipped with an underwater small platform double five-element acoustic positioning array model composed of six hydrophones; a controller, configured to execute the passive acoustic positioning fusion method for underwater small platform detection as described above, and process received sound source signals to output sound source coordinates after fusion processing; wherein the six hydrophones are configured into an upper five-element stereo array and a lower five-element stereo array, the upper five-element stereo array is composed of selected five hydrophones, forms a specific spatial geometric relationship, is used to receive and process signals emitted by an underwater sound source, and determines positioning information of the sound source in the upper five-element stereo array, and the lower five-element stereo array is composed of at least one hydrophone that is not in the upper five-element stereo array, forms another specific spatial geometric relationship, is used to receive and process signals emitted by the underwater sound source, and determines positioning information of the sound source in the lower five-element stereo array.

[0067] In a fourth aspect, the embodiment of the present application provides a computer readable medium, having computer executable instructions stored thereon, and the executable instructions are executed by a processor to implement the passive acoustic positioning fusion method for underwater small platform detection as described above.

[0068] (III) Beneficial Effects

[0069] The beneficial effects of the present application are:

[0070] Firstly, the present application receives the mixed signals observed by each hydrophone on the underwater small platform, and uses the efficient ICA model and power spectrum entropy technology, and uses the preset ICA model and power spectrum entropy technology, to accurately extract the source signal from the complex mixed signal, providing a high-quality data basis for subsequent sound source positioning. This step not only reduces noise interference, but also ensures the accuracy of signal processing.

[0071] Secondly, by establishing a double five-element acoustic positioning array model of the underwater small platform composed of multiple hydrophones, and according to the accurate coordinate positions of the source signal and each hydrophone, the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array in the double five-element stereo array model are calculated respectively. The design of this double five-element stereo array not only improves the positioning accuracy, but also enhances the robustness of the positioning system.

[0072] Then, the method also innovatively introduces the analysis of array installation error, sound speed error and time delay estimation error. Through these error analyses, the distance error, azimuth error and pitch angle error of the sound source coordinates can be more accurately evaluated. This error analysis not only improves the accuracy of positioning, but also makes the positioning result more reliable.

[0073] Furthermore, based on the in-depth analysis of the above-mentioned errors, the method sets corresponding weight coefficients, which intelligently fuse the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array, and output the optimized sound source coordinates. This fusion strategy not only integrates the positioning advantages of double arrays, but also effectively reduces the errors that may occur in single array positioning, thereby outputting more accurate and stable sound source coordinates.

[0074] Therefore, the passive acoustic positioning fusion method provided by the present application provides a more accurate and reliable sound source positioning means for underwater small platform detection, which has important significance for ocean exploration, geological survey and military application fields. BRIEF DESCRIPTION OF DRAWINGS

[0075] Figure 1 The flowchart of the method provided by the embodiment of the present application is shown in the figure;

[0076] Figure 2 The schematic diagram of the source signal and noise signal provided by the embodiment of the present application is shown in the figure;

[0077] Figure 3 The schematic diagram of the ICA noise reduction signal provided by the embodiment of the present application is shown in the figure;

[0078] Figure 4A dual five-element stereo array diagram provided for the embodiment of the application;

[0079] Figure 5 An upper five-element stereo array diagram provided for the embodiment of the application;

[0080] Figure 6 A lower five-element stereo array diagram provided for the embodiment of the application;

[0081] Figure 7 A fusion algorithm diagram provided for the embodiment of the application;

[0082] Figure 8 A distance error σ provided for the embodiment of the application R and D and a relationship diagram;

[0083] Figure 9 An azimuth error σ provided for the embodiment of the application θ and D and a relationship diagram;

[0084] Figure 10 A pitch angle error σ provided for the embodiment of the application φ and D and a relationship diagram. DETAILED DESCRIPTION

[0085] In order to better explain the application, so as to be understood, the application is described in detail below by specific embodiments in combination with the drawings.

[0086] As shown in Figure 1 , the passive acoustic positioning fusion method for underwater small platform detection provided by the embodiment of the application comprises: receiving mixed signals observed by each hydrophone on the underwater small platform, and obtaining source signals from the mixed signals by using a preset ICA model and power spectrum entropy; establishing a dual five-element acoustic positioning array model of the underwater small platform composed of multiple hydrophones, and respectively calculating acoustic source coordinates in an upper five-element stereo array and a lower five-element stereo array in the dual five-element acoustic positioning array model according to the source signals and the coordinate positions of the hydrophones; according to the introduced array shape installation error, sound speed error and time delay estimation error, the distance error, azimuth error and pitch angle error of the acoustic source coordinates are obtained by error analysis; based on the distance error, azimuth error and pitch angle error of the acoustic source positioning, corresponding weight coefficients are set, the acoustic source coordinates in the upper five-element stereo array and the lower five-element stereo array are fused according to the weight coefficients, and then the fused acoustic source coordinates are output.

[0087] Firstly, the present application receives the mixed signals observed by each hydrophone on the underwater small platform, and uses the efficient ICA model and power spectrum entropy technology, and uses the preset ICA model and power spectrum entropy technology, accurately extracts the source signal from the complex mixed signal, and provides high-quality data basis for subsequent sound source positioning. This step not only reduces the noise interference, but also ensures the accuracy of signal processing.

[0088] Secondly, by establishing a double five-element sound positioning array model of the underwater small platform composed of multiple hydrophones, and according to the accurate coordinate positions of the source signals and the hydrophones, the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array in the double five-element stereo array model are calculated respectively. The design of the double five-element stereo array not only improves the positioning accuracy, but also enhances the robustness of the positioning system.

[0089] Then, the method also innovatively introduces the analysis of array installation error, sound speed error and time delay estimation error, which can more accurately evaluate the distance error, azimuth error and pitch angle error of the sound source coordinates. This error analysis not only improves the accuracy of positioning, but also makes the positioning result more reliable.

[0090] Furthermore, based on the in-depth analysis of the above-mentioned various errors, the method sets corresponding weight coefficients, which intelligently fuse the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array, and outputs the optimized sound source coordinates. This fusion strategy not only integrates the positioning advantages of double array elements, but also effectively reduces the errors that may occur in single array element positioning, thereby outputting more accurate and stable sound source coordinates.

[0091] Therefore, the passive sound positioning fusion method provided by the present application provides a more accurate and reliable sound source positioning means for underwater small platform detection, which has important significance for marine exploration, geological exploration and military application fields.

[0092] In order to better understand the above technical solutions, the exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings.

[0093] Specifically, the embodiment of the present application provides a passive sound positioning fusion method for underwater small platform detection, comprising:

[0094] S1, receiving the mixed signals observed by each hydrophone on the underwater small platform, and using the preset ICA model and power spectrum entropy to obtain the source signal from the mixed signals.

[0095] Further, step S1 comprises:

[0096] S11, receiving the mixed signals observed by each hydrophone on the underwater small platform, and confirming that the source signal and the noise signal are statistically independent.

[0097] The time-delay signals received by each hydrophone on the underwater small platform are denoised, and the source signals and the noise signals are statistically independent, i.e., their joint probability density function can be decomposed into the product of their respective probability density functions, which meets the condition of ICA, and the pure source signals can be separated by ICA.

[0098] S12, the real source signals S are separated from the observed signals X by a first conversion formula X = AS using the mixing matrix A pre-constructed in the ICA model.

[0099] S13, an inverse transformation matrix W is found by the Newton iteration method, and a simulated source signal Y close to the real source signal S is obtained based on the inverse transformation matrix W and a second conversion formula Y = WX.

[0100] The ICA model is based on the process that the source signals are converted into observed signals by a mixing matrix. This can be expressed as X = AS, where X is the observed mixed signal, A is the mixing matrix, and S is the unknown source signal. Secondly, an inverse transformation matrix W is found by the Newton iteration method, so that Y obtained by Y = WX is as close as possible to the real source signal S.

[0101] In a specific embodiment, as shown in Figure 2 , signal 1 is the source signal, a 500Hz sinusoidal signal; signal 2 is a Gaussian white noise signal. Six hydrophones arranged on a double five-element stereo array 300m away receive mixed signals superimposed by the source signal and the noise signal. The denoising effect of the ICA method is shown in Figure 3 , independent component 1 is the source signal, and independent component 2 is the noise signal. From the spectrum diagram, it can be seen that the frequency of the separated sinusoidal signal completely matches the source signal.

[0102] S14, the discrete Fourier transform of the simulated source signal Y is performed to obtain the power spectrum density estimate,

[0103] S15, the power spectrum is normalized to ensure that the sum of each frequency component is 1.

[0104] S16, the information entropy is calculated according to the normalized power spectrum to obtain the power spectrum entropy.

[0105] S17, according to the set threshold and the power spectrum entropy, the noise components in each frequency band of the simulated source signal Y are judged, and the source signal is output after the determined noise components are removed.

[0106] In order to more accurately and quickly distinguish which independent component is a noise signal, the application utilizes power spectrum entropy to judge noise component. First, the signal needs to be subjected to discrete Fourier transform (DFT), so as to convert the time domain signal to the frequency domain and obtain power spectrum density estimation. Then, the power spectrum is subjected to normalization processing, so as to ensure that the sum of each frequency component is 1. Finally, the information entropy, i.e. power spectrum entropy, is calculated according to the normalized power spectrum. Noise usually has a larger power spectrum entropy because its frequency components are many and chaotic; and the power spectrum entropy of the signal is smaller because the frequency components of the signal are relatively concentrated. By setting a suitable threshold value, it can be judged whether the main component in a frequency band is noise or effective signal. Through calculation, the source signal power spectrum entropy is 0.55 and the noise power spectrum entropy is 0.04. By selecting a suitable threshold value 0.3, the source signal and the noise signal can be distinguished.

[0107] S2, an underwater small platform double five-element acoustic positioning array model composed of multiple hydrophones is established, and the coordinates of the sound source in the upper five-element stereo array and the lower five-element stereo array in the double five-element acoustic positioning array model are calculated according to the source signal and the coordinate positions of the hydrophones.

[0108] Further, the step S2 comprises:

[0109] S21, an underwater small platform double five-element acoustic positioning array model composed of six hydrophones is established.

[0110] S22, the coordinate position of each hydrophone in the Cartesian three-dimensional rectangular coordinate system, the coordinate of the sound source in the three-dimensional rectangular coordinate system and the sound wave propagation time delay value of the sound source to each hydrophone are determined.

[0111] S23, for the upper five-element stereo array, the source signal, the coordinate position of the hydrophone and the coordinate position of the sound source are utilized to calculate the coordinate of the sound source in the upper five-element stereo array through the time delay estimation positioning algorithm.

[0112] S24, for the lower five-element stereo array, the source signal, the coordinate position of the hydrophone and the coordinate position of the sound source are utilized to calculate the coordinate of the sound source in the lower five-element stereo array through the time delay estimation positioning algorithm.

[0113] Among them, the six hydrophones are configured into an upper five-element stereo array and a lower five-element stereo array, the upper five-element stereo array is composed of five selected hydrophones, forms a specific spatial geometric relationship, is used to receive and process the signal emitted by the underwater sound source, and determines the positioning information of the sound source in the upper five-element stereo array, and the lower five-element stereo array is composed of at least one hydrophone which is not in the upper five-element stereo array, forms another specific spatial geometric relationship, is used to receive and process the signal emitted by the underwater sound source, and determines the positioning information of the sound source in the lower five-element stereo array.

[0114] In a specific embodiment, the underwater small platform acoustic positioning array model is composed of 6 hydrophones, which are represented by M1, M2, M3, M4, M5, and M6 respectively. Figure 4 As shown, a Cartesian three-dimensional rectangular coordinate system is established, and M1, M2, M3, M4, M5, and M6 are respectively located on each coordinate axis, wherein M1, M2, M3, M4, and M5 constitute an upper five-element three-dimensional array, and M1, M2, M3, M4, and M6 constitute a lower five-element three-dimensional array, and the two arrays together constitute a double five-element three-dimensional array.

[0115] Furthermore, step S23 includes:

[0116] S231 : For the upper five-element stereo array including the first hydrophone M1 , the second hydrophone M2 , the third hydrophone M3 , the fourth hydrophone M4 and the fifth hydrophone M5 , a reference hydrophone is set, and time delay values ​​of other hydrophones relative to the reference hydrophone are determined.

[0117] S232 , calculating the acoustic path difference of each hydrophone using the time delay and sound velocity from the sound source to the first hydrophone M1 , the second hydrophone M2 , the third hydrophone M3 , the fourth hydrophone M4 and the fifth hydrophone M5 .

[0118] S233. Obtain the distance difference between the sound source and the fifth hydrophone M5 based on the coordinate position of the fifth hydrophone M5 and the coordinate position of the sound source. Combine the rectangular coordinates of the sound source and the acoustic path differences of the hydrophones and use geometric relationships to obtain a positioning relationship in the rectangular coordinates of the upper five-element stereo array.

[0119] S234, according to the set condition R1>>d i1 , the sound path difference of each hydrophone, the conversion formula of spherical coordinates and rectangular coordinate system obtained by the rectangular coordinates and spherical coordinates of the sound source, and the positioning relationship under the rectangular coordinates of the upper five-element stereo array, the conversion relationship under the rectangular coordinates of the upper five-element stereo array is obtained.

[0120] S235 , substituting the conversion relationship in the rectangular coordinates of the upper five-element three-dimensional array into the spherical coordinates of the sound source coordinates to obtain the spherical coordinates of the sound source in the upper five-element three-dimensional array.

[0121] In a specific embodiment, the five-element stereo array uses M5 as the reference hydrophone, assuming that the time delays from the sound source to M1, M2, M3, M4 and M5 are τ 15 , τ 25 , τ 35 , τ 45 The coordinates of the six hydrophones M1, M2, M3, M4, M5, and M6 are: (D, 0, 0), (0, D, 0), (-D, 0, 0), (0, -D, 0), (0, 0, D), and (0, 0, -D).

[0122] The coordinates of the target sound source S in a three-dimensional rectangular coordinate system are (x, y, z). Let the projection point in the xoy plane be S', the azimuth angle be θ, and the elevation angle be Suppose that the sound wave of the target sound source is propagated in the form of a spherical wave, and the propagation speed is c. Then the sound path differences of the hydrophones are d ij (d ij = c·τ ij , i, j = 1, 2, 3, 4, 5, 6).

[0123] The sound source positioning of the upper five-element stereo array is described in detail as follows:

[0124] Reference Figure 5 First, the upper five-element stereo array composed of M1, M2, M3, M4, and M5 is used. Suppose that the rectangular coordinates of the sound source in the upper five-element stereo array are S(x, y, z), and the spherical coordinates are R5 is the distance from the sound source S to M5. Then, by using the geometric relationship, the positioning relationship formula of the upper five-element stereo array in the rectangular coordinates is obtained as follows:

[0125]

[0126] The conversion formula between the spherical coordinates and the rectangular coordinates is as follows:

[0127]

[0128] The target S is generally located in the far field, i.e., R5 » cτ ij By combining the above two formulas (1) and (2), the following formula is obtained:

[0129]

[0130] The spherical coordinates of the sound source in the upper five-element stereo array are as follows:

[0131]

[0132] In the formula, R i , i = 1, 2, 3, 4, 5, 6, represents the distance from the sound source to the ith hydrophone, θ i , i = 1, 2, 3, 4, 5, 6, represents the azimuth angle of the sound source to the ith hydrophone, , and φ , i = 1, 2, 3, 4, 5, 6, represents the elevation angle of the sound source to the ith hydrophone.

[0133] Correspondingly, step S24 includes:

[0134] S241, for the lower five-element stereo array composed of the first hydrophone M1, the second hydrophone M2, the fourth hydrophone M4, and the sixth hydrophone M6, a reference hydrophone is set, and the time delay values of the other hydrophones relative to the reference hydrophone are determined.

[0135] S242, the sound path difference of each hydrophone is calculated by using the time delay value of the sound source to the first hydrophone M1, the second hydrophone M2, the third hydrophone M3, the fourth hydrophone M4 and the sixth hydrophone M6 and the sound velocity.

[0136] S243, the distance difference information of the sound source to the sixth hydrophone M6 is obtained according to the coordinate position of the sixth hydrophone M6 and the coordinate position of the sound source, and the positioning relationship formula of the lower five-element stereo array in the rectangular coordinate system is obtained by combining the rectangular coordinates of the sound source and the sound path difference of each hydrophone and using the geometric relationship.

[0137] S244, according to the set condition R1>>d i1 , the sound path difference of each hydrophone, the conversion formula of the spherical coordinate and the rectangular coordinate system and the positioning relationship of the lower five-element stereo array in the rectangular coordinate, the conversion relationship formula of the lower five-element stereo array in the rectangular coordinate is obtained.

[0138] S245, the spherical coordinates of the sound source in the lower five-element stereo array are obtained by substituting the conversion relationship formula of the lower five-element stereo array in the rectangular coordinate into the spherical coordinates of the sound source coordinates.

[0139] In a specific embodiment, with reference Figure 6 , the lower five-element stereo array composed of M1, M2, M3, M4 and M6 is used, and R6 is the distance from the sound source S to M6.

[0140] The positioning relationship formula of the lower five-element stereo array in the rectangular coordinate is:

[0141]

[0142] The target S is generally located in the far field, that is, R6>>cτ ij , the conversion relationship formula of the lower five-element stereo array in the rectangular coordinate is obtained by combining the above (2) and (5):

[0143]

[0144] The spherical coordinates of the sound source in the lower five-element stereo array are:

[0145]

[0146] S3, the distance error, the azimuth error and the pitch angle error of the sound source coordinates are obtained by error analysis according to the introduced array installation error, the sound velocity error and the time delay estimation error.

[0147] Further, step S3 comprises:

[0148] S31, the partial derivatives of the distance, azimuth and pitch angle of the sound source coordinates are calculated, and the array installation error, the sound velocity error and the time delay estimation error are introduced into the partial derivatives to obtain the mathematical expressions of the distance error, the azimuth error and the pitch angle error.

[0149] S32, based on the mathematical expression of the distance error, the azimuth error and the pitch error, the distance error, the azimuth error and the pitch error of the sound source coordinate are obtained by error analysis

[0150] In a specific embodiment, according to the error indirect propagation theory, the target positioning accuracy can be obtained by partial derivative of the positioning formula, and the distance error, the azimuth error and the pitch error are respectively:

[0151]

[0152]

[0153]

[0154] In the formula, σ D is the array installation error, σ C is the sound speed error, is the time delay estimation error.

[0155] In another specific embodiment, D and c can be corrected in advance, so that σ D and σ C are negligible relative to , so the distance error, the azimuth error and the pitch error can be simplified as:

[0156]

[0157]

[0158]

[0159] Assuming that the time delay error of different hydrophones is the same, that is, For far field detection, assuming that R0≈R, the distance error, the azimuth error and the pitch error can be further expressed as:

[0160]

[0161]

[0162]

[0163] S4, based on the distance error, the azimuth error and the pitch error of the sound source positioning, the corresponding weight coefficients are set, and the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array are fused according to the weight coefficients, and then the sound source coordinates after fusion processing are output.

[0164] Further, with reference to Figure 7 , step S4 comprises:

[0165] S41, determine the distance error, azimuth error and elevation error generated in the sound source positioning process.

[0166] S42, according to the least square method, the reciprocal of the square of the corresponding error is weighted to obtain the weight coefficient corresponding to the distance error, azimuth error and elevation error.

[0167] After identifying the distance error, azimuth error and elevation error, the corresponding weight coefficients need to be set for these errors. These weight coefficients will be used in subsequent weighted processing to correct and optimize the calculation results of sound source coordinates. The setting of weight coefficients should be based on the size and importance of errors to ensure that the weighted processing can effectively reduce the influence of errors on the final results.

[0168] S43, using the weight coefficient, the sound source coordinates obtained in the upper five-element stereo array and the lower five-element stereo array are weighted respectively.

[0169] Using the weight coefficient set in step S42, the sound source coordinates obtained in the upper five-element stereo array and the lower five-element stereo array are weighted respectively. The purpose of this step is to correct the errors in the original coordinate data by introducing weight coefficients, so as to improve the accuracy of sound source positioning. Weighted processing can consider the influence of different errors on positioning results and adjust the coordinate values accordingly, so that they are closer to the true sound source position.

[0170] S44, the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array after weighted processing are fused.

[0171] After completing the weighted processing of the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array, the two weighted coordinates are fused. The purpose of fusion is to integrate the positioning results of the two arrays to further improve the accuracy and stability of positioning. Through fusion processing, a more accurate and reliable sound source coordinate can be obtained.

[0172] S45, output the sound source coordinate after fusion processing. This coordinate is the integrated positioning result of the upper five-element stereo array and the lower five-element stereo array, and is obtained after weighted processing and fusion, so it has higher accuracy and reliability. This coordinate can be used as the basis data for subsequent underwater detection, navigation or target tracking tasks.

[0173] wherein,

[0174] The weight coefficient is:

[0175]

[0176] In the formula, k R1 , k θ1 , are the weight coefficients corresponding to the distance error, azimuth error and elevation error of the upper five-element stereo array, k R2 、k θ2 、 are the weight coefficients corresponding to the distance error, azimuth error and elevation error of the lower five-element stereo array, σ R1 , σ θ1 、 are the distance error, azimuth error and elevation error of the upper five-element stereo array, σ R2 , σ θ2 、 They are the distance error, azimuth error and elevation error of the lower five-element stereo array respectively.

[0177] The coordinates of the sound source after fusion processing are:

[0178]

[0179] In addition, the present invention also includes:

[0180] S5. Utilize the upper and lower five-element stereo arrays to collect real-time underwater environmental data, such as sound pressure, particle velocity data, and ambient noise data. Furthermore, the array's received signal quality, including signal-to-noise ratio and signal strength, is monitored in real time. Subsequently, based on the results of environmental perception and array performance monitoring, the need for array adjustment strategies is triggered. The constructed performance prediction model is used to determine the array configuration parameters that require adjustment, such as element spacing, array shape (linear, circular, matrix, etc.), and number of elements.

[0181] Next, the configuration with the best performance is selected as the adjustment target. Automated mechanical devices (such as underwater robots and electric actuators) automatically or semi-automatically adjust the array configuration parameters, including increasing or decreasing the element spacing and changing the array shape. For example, if strong signal interference is detected in a certain area, the element spacing in that area can be automatically adjusted or the number of elements can be increased to enhance signal reception.

[0182] During the adjustment process, sensors and monitoring systems acquire real-time array status information. This real-time status is compared with the adjustment plan to ensure that adjustments are being made accurately according to the strategy.

[0183] in,

[0184] The performance prediction function is:

[0185]

[0186] Where P is the predicted positioning performance index (the higher the better), SNR is the signal-to-noise ratio, which represents the ratio of signal to noise, DI is the nonuniformity of the array element spacing, which can be measured by standard deviation or other statistics, BW is the signal bandwidth, which affects the resolution and anti-interference capability, IN is the intensity of the interference noise, and w1, w2, w3, and w4 are weight coefficients, which are determined through experiments or expert knowledge.

[0187] The array adjustment strategy is expressed as a transformation of array parameters (such as array element positions):

[0188]

[0189] Where, d new is the adjusted array element spacing, d old is the element spacing before adjustment, Δd is the step size of each adjustment, which can be set according to actual conditions, sign(x) is the sign function, which returns the positive or negative sign of x. It is the partial derivative of the performance prediction function P with respect to the array element spacing d, indicating the trend of performance changing with array element spacing.

[0190] In another specific embodiment, it is shown by formula (13): when σ τ When σ is constant, R With R, D and Assume that R = 1000m, the direction angle is 30°, and the delay is a uniformly distributed random error (σ τ =1μs), σ R The relationship with R and D is as follows Figure 8 As shown. In D and When it is close to 0, σ θ Get the maximum value. Overall, When σ is fixed, R It decreases with the increase of D; In the fixed case, when When σ R Follow decreases with the increase of When σ R Follow The minimum value is related to the fusion algorithm.

[0191] Formula (14) shows that when σ τ When σ is constant, θ With D and Assume that R = 1000m, the direction angle is 30°, and the delay is a uniformly distributed random error (σ τ =1μs), σ θ With D and The relationship as Figure 9 As shown. In D and When it is close to 0, σ θ Get the maximum value. Overall, σ θ Both D and decreases with the increase of .

[0192] Formula (15) shows that when σ τ When σ is constant, φ With D and Assume that R = 1000m, the direction angle is 30°, and the delay is a uniformly distributed random error (σ τ =1μs), σ θ With D and The relationship as Figure 10 As shown. θ When D is close to 0, the error is relatively large.

[0193] Assuming the array center is at the origin, the azimuth error of the dual five-element stereo array is compared with that of the single five-element stereo array. According to Table 1, the dual five-element stereo array has a smaller improvement in the accuracy of solving the target azimuth than the single five-element stereo array, but it still has a high accuracy, and the percentage error can be kept within 10 -6 Below order of magnitude.

[0194] Table 1 Comparative analysis of direction angle estimation errors

[0195]

[0196] Comparison of the pitch angle error between the dual five-element stereo array and the single five-element stereo array. According to Table 2, the accuracy of the dual five-element stereo array in solving the target pitch angle is improved by about 3 orders of magnitude compared with the single five-element stereo array, and the percentage error can basically be maintained at 10 -5 Below order of magnitude.

[0197] Table 2 Comparative analysis of pitch angle estimation errors

[0198]

[0199] Comparing the distance estimation errors of the dual five-element stereo array and the single five-element stereo array. Table 3 shows that the dual five-element stereo array improves the accuracy of target distance estimation by approximately three orders of magnitude compared to the single five-element stereo array. At a detection distance of 1 km, the error can be kept within 1 cm.

[0200] Table 3 Comparative analysis of distance estimation errors

[0201]

[0202] In addition, the embodiment of the present application provides a passive acoustic positioning fusion system for underwater small platform detection, comprising: a source signal acquisition module, configured to receive mixed signals observed by each hydrophone on the underwater small platform, and obtain source signals from the mixed signals by using a preset ICA model and power spectrum entropy. A sound source coordinate solving module is configured to establish a dual five-element acoustic positioning array model of the underwater small platform composed of multiple hydrophones, and calculate the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array in the dual five-element acoustic positioning array model according to the source signals and the coordinate positions of the hydrophones. An error term introduction module is configured to obtain distance error, azimuth error and pitch angle error of the sound source coordinates by error analysis according to introduced array installation error, sound velocity error and time delay estimation error. A fusion processing module is configured to set corresponding weight coefficients based on the distance error, azimuth error and pitch angle error of the sound source positioning, fuse the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array according to the weight coefficients, and then output the sound source coordinates after fusion processing.

[0203] In addition, the embodiment of the present application provides a passive acoustic positioning fusion system for underwater small platform detection, comprising: a source signal acquisition module, configured to receive mixed signals observed by each hydrophone on the underwater small platform, and obtain source signals from the mixed signals by using a preset ICA model and power spectrum entropy. A sound source coordinate solving module is configured to establish a dual five-element acoustic positioning array model of the underwater small platform composed of multiple hydrophones, and calculate the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array in the dual five-element acoustic positioning array model according to the source signals and the coordinate positions of the hydrophones. An error term introduction module is configured to obtain distance error, azimuth error and pitch angle error of the sound source coordinates by error analysis according to introduced array installation error, sound velocity error and time delay estimation error. A fusion processing module is configured to set corresponding weight coefficients based on the distance error, azimuth error and pitch angle error of the sound source positioning, fuse the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array according to the weight coefficients, and then output the sound source coordinates after fusion processing.

[0204] In addition, the embodiment of the present application provides a passive acoustic positioning fusion system for underwater small platform detection, comprising: a source signal acquisition module, configured to receive mixed signals observed by each hydrophone on the underwater small platform, and obtain source signals from the mixed signals by using a preset ICA model and power spectrum entropy. A sound source coordinate solving module is configured to establish a dual five-element acoustic positioning array model of the underwater small platform composed of multiple hydrophones, and calculate the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array in the dual five-element acoustic positioning array model according to the source signals and the coordinate positions of the hydrophones. An error term introduction module is configured to obtain distance error, azimuth error and pitch angle error of the sound source coordinates by error analysis according to introduced array installation error, sound velocity error and time delay estimation error. A fusion processing module is configured to set corresponding weight coefficients based on the distance error, azimuth error and pitch angle error of the sound source positioning, fuse the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array according to the weight coefficients, and then output the sound source coordinates after fusion processing.

[0205] In summary, the embodiment of the present application provides a passive acoustic positioning fusion method, system, device and medium for underwater small platform detection, and the core advantage of the present application lies in the innovative underwater acoustic positioning algorithm. By adopting a unique dual five-element three-dimensional hydrophone array design, combined with a positioning fusion algorithm based on distance and angle error weighting, the accuracy and stability of the underwater target positioning result are significantly improved. In the signal preprocessing stage, the present application ingeniously uses the ICA method to denoise the input signal, so as to obtain more accurate time delay information, and lays a solid foundation for subsequent accurate positioning. In the array design, the present application ingeniously sets six array elements to form a dual five-element three-dimensional array, which not only enhances the signal receiving capability, but also further improves the positioning accuracy through the weight coefficient fusion technology based on distance and angle error. This innovative design enables the present application to more accurately lock the underwater target in practical application. Through systematic whole process design and technical innovation of each part, the present application successfully overcomes many problems in the existing underwater acoustic positioning technology, not only performs well in practical application, but also opens up a new path for the further development of underwater acoustic positioning technology. Overall, the present application brings significant progress to the underwater detection field with its unique technical advantages and innovative solutions.

[0206] Since the system / device described in the above-mentioned embodiments of the present application is used for the method of the above-mentioned embodiments of the present application, the specific structure and modification of the system / device can be understood by those skilled in the art based on the method described in the above-mentioned embodiments of the present application, and thus will not be described here. Any system / device used in the method of the above-mentioned embodiments of the present application belongs to the scope of the present application.

[0207] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments after learning the basic creative concept. Therefore, the present application scheme should be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0208] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the present application scheme and its equivalent technologies, the present application should also include these modifications and variations.

Claims

1. A passive acoustic positioning fusion method for underwater small platform detection, characterized in that: include: Receive the mixed signal observed by each hydrophone on the underwater small platform, and use the preset ICA model and power spectrum entropy to obtain the source signal from the mixed signal; A dual five-element acoustic positioning array model for an underwater small platform consisting of multiple hydrophones was established. Based on the source signal and the coordinate positions of each hydrophone, the coordinates of the sound source in the upper five-element stereo array and the lower five-element stereo array of the dual five-element acoustic positioning array model were calculated. Based on the introduced array installation error, sound speed error, and time delay estimation error, the distance error, azimuth error, and elevation error to the sound source coordinates are obtained through error analysis. Based on the distance error, azimuth error, and elevation error of the sound source localization, corresponding weight coefficients are set. The sound source coordinates in the upper and lower five-element stereo arrays are fused according to the weight coefficients, and then the fused sound source coordinates are output.

2. The passive acoustic positioning fusion method for underwater small platform detection according to claim 1, characterized in that: The mixed signal observed by each hydrophone on the underwater small platform is received, and the source signal is obtained from the mixed signal using the preset ICA model and power spectrum entropy, including: Receive the mixed signal observed by each hydrophone on the underwater small platform and confirm that the source signal and the noise signal are statistically independent; Using the pre-built mixing matrix A in the ICA model, the true source signal S is separated from the observed signal X through the first transformation formula X = AS; An inverse transformation matrix W is found by Newton iteration method, and based on the inverse transformation matrix W and the second transformation formula Y=WX, a simulated source signal Y close to the real source signal S is obtained; Perform discrete Fourier transform on the analog source signal Y to obtain the power spectrum density estimate, Normalize the power spectrum to ensure that the sum of all frequency components is 1; Calculate the information entropy based on the normalized power spectrum to obtain the power spectrum entropy; According to the set threshold and power spectrum entropy, the noise components in each frequency band of the analog source signal Y are determined, and the source signal is output after the determined noise components are removed.

3. The passive acoustic positioning fusion method for underwater small platform detection according to claim 1, characterized in that: A dual five-element acoustic positioning array model of an underwater small platform consisting of multiple hydrophones is established. Based on the source signal and the coordinate positions of each hydrophone, the coordinates of the sound source in the upper five-element stereo array and the lower five-element stereo array in the dual five-element acoustic positioning array model are calculated respectively. Establish a dual five-element acoustic positioning array model for an underwater small platform consisting of six hydrophones; Determine the coordinate position of each hydrophone in the Cartesian three-dimensional rectangular coordinate system, the coordinates of the sound source in the three-dimensional rectangular coordinate system, and the sound wave propagation delay value from the sound source to each hydrophone; For the upper five-element stereo array, the coordinates of the sound source in the upper five-element stereo array are calculated by using the obtained source signal, the coordinate position of the hydrophone and the coordinate position of the sound source through the time delay estimation positioning algorithm; For the lower five-element stereo array, the coordinates of the sound source in the lower five-element stereo array are calculated by using the obtained source signal, the coordinate position of the hydrophone and the coordinate position of the sound source through the time delay estimation positioning algorithm; Among them, the six hydrophones are configured into an upper five-element stereo array and a lower five-element stereo array. The upper five-element stereo array is composed of five selected hydrophones, forming a specific spatial geometric relationship, which is used to receive and process signals emitted by underwater sound sources to determine the positioning information of the sound sources in the upper five-element stereo array. The hydrophones formed in the lower five-element stereo array contain at least one hydrophone that does not exist in the upper five-element stereo array, forming another specific spatial geometric relationship, which is used to receive and process signals emitted by underwater sound sources to determine the positioning information of the sound sources in the lower five-element stereo array.

4. The passive acoustic positioning fusion method for underwater small platform detection according to claim 3, characterized in that: For the upper five-element stereo array, the coordinates of the sound source in the upper five-element stereo array are calculated by using the obtained source signal, the coordinate position of the hydrophone, and the coordinate position of the sound source through the time delay estimation positioning algorithm, including: For the upper five-element stereo array including the first hydrophone M1, the second hydrophone M2, the third hydrophone M3, the fourth hydrophone M4 and the fifth hydrophone M5, a reference hydrophone is set, and time delay values ​​of other hydrophones relative to the reference hydrophone are determined; The acoustic path difference of each hydrophone is calculated using the time delay and sound velocity from the sound source to the first hydrophone M1, the second hydrophone M2, the third hydrophone M3, the fourth hydrophone M4 and the fifth hydrophone M5; The distance difference between the sound source and the fifth hydrophone M5 is obtained based on the coordinate position of the fifth hydrophone M5 and the coordinate position of the sound source. The positioning relationship of the upper five-element stereo array in rectangular coordinates is obtained by combining the rectangular coordinates of the sound source and the acoustic path differences of each hydrophone using geometric relationships. According to the setting condition R1>>d i1 , the acoustic path difference of each hydrophone, the conversion formula between spherical coordinates and rectangular coordinates obtained from the rectangular coordinates and spherical coordinates of the sound source, and the positioning relationship under the rectangular coordinates of the upper five-element three-dimensional array, to obtain the conversion relationship under the rectangular coordinates of the upper five-element three-dimensional array; Substitute the conversion relationship under the rectangular coordinates of the upper five-element three-dimensional array into the spherical coordinates of the sound source coordinates to obtain the spherical coordinates of the sound source in the upper five-element three-dimensional array; in, The acoustic path difference of each hydrophone is: d ij =c·τ ij Where c represents the speed of sound in water, τ ij , i, j = 1, 2, 3, 4, 5, 6 represent the time delay from the sound source to the i-th hydrophone; The rectangular coordinates of the sound source are: S(x,y,z); The spherical coordinates of the sound source are The positioning relationship of the upper five-element three-dimensional array in rectangular coordinates is: Where D represents the distance from the hydrophone to the origin of the coordinate system, R i , i = 1, 2, 3, 4, 5, 6 represents the distance from the sound source to the i-th hydrophone; The conversion formula between spherical coordinates and rectangular coordinates is: The conversion relationship of the upper five-element three-dimensional array in rectangular coordinates is: The spherical coordinates of the sound source in the upper five-element stereo array are: Where θ i ,i=1,2,3,4,5,6, represents the azimuth angle from the sound source to the i-th hydrophone, represents the elevation angle from the sound source to the i-th hydrophone.

5. The passive acoustic positioning fusion method for underwater small platform detection according to claim 3, characterized in that: For the lower five-element stereo array, the coordinates of the sound source in the lower five-element stereo array are calculated using the obtained source signal, the coordinate position of the hydrophone, and the coordinate position of the sound source through the time delay estimation positioning algorithm. For the lower five-element stereo array including the first hydrophone M1, the second hydrophone M2, the fourth hydrophone M4 and the sixth hydrophone M6, a reference hydrophone is set, and time delay values ​​of the other hydrophones relative to the reference hydrophone are determined; The acoustic path difference of each hydrophone is calculated using the time delay and sound velocity from the sound source to the first hydrophone M1, the second hydrophone M2, the third hydrophone M3, the fourth hydrophone M4 and the sixth hydrophone M6; The distance difference between the sound source and the sixth hydrophone M6 is obtained based on the coordinate position of the sixth hydrophone M6 and the coordinate position of the sound source. The positioning relationship of the lower five-element stereo array in rectangular coordinates is obtained by combining the rectangular coordinates of the sound source and the acoustic path differences of each hydrophone using geometric relationships. According to the setting condition R1>>d i1 , the acoustic path difference of each hydrophone, the conversion formula between spherical coordinates and rectangular coordinates, and the positioning relationship of the lower five-element three-dimensional array in rectangular coordinates, to obtain the conversion relationship of the lower five-element three-dimensional array in rectangular coordinates; Substitute the conversion relationship under the rectangular coordinates of the lower five-element three-dimensional array into the spherical coordinates of the sound source coordinates to obtain the spherical coordinates of the sound source in the lower five-element three-dimensional array; in, The acoustic path difference of each hydrophone is: d ij =c·τ ij ; Where c represents the speed of sound in water, τ ij , i, j = 1, 2, 3, 4, 5, 6 represent the time delay from the sound source to a certain hydrophone; The rectangular coordinates of the sound source are: S(x,y,z); The spherical coordinates of the sound source are The positioning relationship of the five-element three-dimensional array in rectangular coordinates is: Where D represents the distance from the hydrophone to the origin of the coordinate system, R i , i=1,2,3,4,5,6 represents the distance from the sound source to a hydrophone; The conversion formula between spherical coordinates and rectangular coordinates is: The conversion relationship of the rectangular coordinates of the lower five-element three-dimensional array is: The spherical coordinates of the sound source in the lower five-element stereo array are: Where θ i ,i=1,2,3,4,5,6, represents the azimuth angle from the sound source to the i-th hydrophone, represents the elevation angle from the sound source to the i-th hydrophone.

6. The passive acoustic positioning fusion method for underwater small platform detection according to claim 4 or 5, characterized in that: Based on the introduced array installation error, sound speed error, and time delay estimation error, the distance error, azimuth error, and elevation angle error to the sound source coordinates are obtained through error analysis, including: The partial derivatives of the distance, azimuth, and elevation of the sound source coordinates are calculated respectively. Array installation error, sound speed error, and time delay estimation error are introduced into the partial derivatives to obtain mathematical expressions for the distance error, azimuth error, and elevation error. Based on the mathematical expressions of distance error, azimuth error and elevation error, the distance error, azimuth error and elevation error of the sound source coordinates are obtained through error analysis; in, The distance error is: The azimuth error is: The pitch angle error is: Where σ D is the formation installation error, σ C is the sound velocity error, is the delay estimation error.

7. The passive acoustic positioning fusion method for underwater small platform detection according to claim 4 or 5, characterized in that: Based on the distance error, azimuth error, and pitch error of the sound source localization, the corresponding weight coefficients are set. The sound source coordinates in the upper five-element stereo array and the lower five-element stereo array are fused according to the weight coefficients. The output of the fused sound source coordinates includes: Determine the distance error, azimuth error and elevation error generated during sound source localization; According to the least square method, the inverse of the square of the corresponding error is used for weighting to obtain the weight coefficients corresponding to the range error, azimuth error and pitch angle error; Using the weight coefficients, the sound source coordinates obtained from the upper five-element stereo array and the lower five-element stereo array are weighted respectively; Fusing the sound source coordinates in the weighted upper five-element stereo array and the lower five-element stereo array; Output the coordinates of the sound source after fusion processing; in, The weight coefficient is: Where k R1 、k θ1 、 are the weight coefficients corresponding to the distance error, azimuth error and elevation error of the upper five-element stereo array, k R2 、k θ2 、 are the weight coefficients corresponding to the distance error, azimuth error and elevation error of the lower five-element stereo array, σ R1 , σ θ1 、 are the distance error, azimuth error and elevation error of the upper five-element stereo array, σ R2 , σ θ2 、 They are the range error, azimuth error and elevation error of the lower five-element stereo array respectively; The coordinates of the sound source after fusion processing are:

8. A passive acoustic positioning fusion system for underwater small platform detection, characterized in that: include: The source signal acquisition module is used to receive the mixed signal observed by each hydrophone on the underwater small platform and obtain the source signal from the mixed signal using the preset ICA model and power spectrum entropy; The sound source coordinate calculation module is used to establish a dual five-element acoustic positioning array model of an underwater small platform composed of multiple hydrophones. Based on the source signal and the coordinate positions of each hydrophone, the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array in the dual five-element acoustic positioning array model are calculated respectively. The error term introduction module is used to calculate the distance error, azimuth error, and elevation error to the sound source coordinates through error analysis based on the introduced array installation error, sound speed error, and time delay estimation error; The fusion processing module is used to set corresponding weight coefficients based on the distance error, azimuth error and pitch angle error of sound source positioning, fuse the sound source coordinates in the upper five-element stereo array and the lower five-element stereo array according to the weight coefficients, and then output the sound source coordinates after fusion processing.

9. An underwater small platform sound source positioning system, characterized in that: include: An underwater small platform equipped with a dual five-element acoustic positioning array model consisting of six hydrophones; A controller configured to execute the passive acoustic positioning fusion method for underwater small platform detection according to any one of claims 1 to 7, process the received sound source signal to output the coordinates of the sound source after fusion processing; Among them, the six hydrophones are configured into an upper five-element stereo array and a lower five-element stereo array. The upper five-element stereo array is composed of five selected hydrophones, forming a specific spatial geometric relationship, which is used to receive and process signals emitted by underwater sound sources to determine the positioning information of the sound sources in the upper five-element stereo array. The hydrophones formed in the lower five-element stereo array contain at least one hydrophone that does not exist in the upper five-element stereo array, forming another specific spatial geometric relationship, which is used to receive and process signals emitted by underwater sound sources to determine the positioning information of the sound sources in the lower five-element stereo array.

10. A computer-readable medium having computer-executable instructions stored thereon, characterized in that: When the executable instructions are executed by the processor, the passive acoustic positioning fusion method for underwater small platform detection as described in any one of claims 1 to 7 is implemented.

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