Self-similar multi-aperture nested microphone array design method and system

Abstract

The invention discloses a self-similar multi-aperture nested microphone array design method and system, and the method comprises the following steps: S1, confirming the aperture distribution of microphones in all arrays, enabling the aperture in a large array to be multiplexed in a sub-array under the condition that the formation is not changed, and obtaining the radial aperture distribution of the sub-array; s2, according to the sub-array radial aperture distribution and the sub-array circumferential distribution rule obtained in the step S1, array arrangement of all arrays and total array arrangement after nesting are obtained; s3, according to a specified target resolution constraint requirement and the array arrangement and the nested total array arrangement obtained in the step S2, realizing sub-array weighting function optimization and maximum gain function optimization; and S4, according to the optimized sub-array weighting function and the maximum gain function in the S3, in combination with a specified gain function threshold, obtaining an applicable frequency range of each sub-array and an optimized weighting function coefficient of each frequency sub-array.

Description

Technical Field

[0001] The present invention belongs to the technical field of microphone arrays, and in particular relates to a method and system for designing a self-similar multi-aperture nested microphone array. Background Art

[0002] Microphone array technology has become one of the main means of modern acoustic measurement. Compared with a single microphone measurement point, it can effectively locate the position and intensity of the sound source, providing guidance for noise control and noise reduction design. In the study of external noise of large passenger aircraft, relevant test applications are generally carried out in open / closed acoustic wind tunnels and field flight tests. In order to obtain better sound source localization effects, it is necessary to optimize the array formation accordingly to meet the performance requirements of spatial resolution and dynamic range, such as multi-arm spiral formation design, iterative optimization design, global optimization methods, and adaptive formation optimization design. However, these methods are all for a single array.

[0003] When the frequency range of the array target design is large, it is difficult for a single array to simultaneously meet the array resolution and dynamic range requirements. At the same time, the required array channel scale is further enlarged, and multiple sub-arrays need to be nested. Different sub-arrays are selected for different frequency ranges, and each sub-array shares some microphones to improve the microphone channel utilization. The most representative work is the nested array design method used by NASA in the field flyover noise source location test of large passenger aircraft.

[0004] Figure 1 The 5-layer nested array designed by NASA in the QTD2 project has a total of 614 microphones. The microphone reuse ratio of this design is relatively low, and the applicable frequency range of different sub-arrays is affected by human experience. In the 2015 QTD3 project, see Figure 2 As shown in the figure, the array size reaches 840. At this time, the allocation and sharing of microphones between sub-arrays is more complicated, requiring careful optimization and trade-offs. The envelope threshold method of different sub-array positioning results quantitatively gives the frequency range of each sub-array, reducing the interference of subjective factors, but from Figure 3 It can be reflected that in some cases no subarray exceeds the set threshold, or multiple subarrays meet the threshold requirements. In 2020, Boeing's green flight demonstration project further expanded this nested design method to 960 channels.

[0005] In summary, especially for large passenger aircraft field flight tests, the target frequency range of sound source positioning is large, and the size of the microphone array is also larger, so it is necessary to carry out the nested design of multiple sub-array formations. However, the current design method is relatively complex, and the microphone reuse and sharing method and the applicable frequency range are affected by human experience.

[0006] Therefore, a new multi-aperture nested array design method needs to be designed. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method and system for designing a self-similar multi-aperture nested microphone array in view of the deficiencies of the above-mentioned prior art.

[0008] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0009] A method for designing a self-similar multi-aperture nested microphone array, the method comprising the following steps:

[0010] S1, confirm the aperture distribution of microphones in all arrays, so that the apertures in the large array can be reused in the sub-array without changing the array, and obtain the radial aperture distribution of the sub-array;

[0011] S2, according to the sub-array radial aperture distribution and sub-array circumferential distribution rules obtained in S1, obtain the array formation arrangement of each array and the total array arrangement after nesting;

[0012] S3, according to the specified target resolution constraint requirements and the array formation arrangement obtained in S2 and the total array formation arrangement after nesting, realize subarray weight function optimization and maximum gain function optimization;

[0013] S4: According to the subarray weight function and the maximum gain function optimized in S3, combined with the specified gain function threshold, the applicable frequency range of each subarray and the optimized weight function coefficient of each frequency subarray are obtained.

[0014] Preferably, the design constraints of the radial aperture distribution of the subarray in S1 include:

[0015] Subarray frequency range, resolution, dynamic range, number of microphones, and subarray formation and nesting rules.

[0016] Preferably, the method of confirming in S1 that the aperture distribution method of all microphones in the array is a planar beamforming method includes:

[0017] For the planar beamforming method, the spatial resolution is related to the source frequency, the source plane distance, and the aperture size as follows:

[0018]

[0019] In the formula, A is an empirical constant, Y is the distance between the array scanning plane and the sound source plane, D is the array aperture, and f is the sound source frequency;

[0020] According to the requirements of spatial resolution, subarray frequency range and number of available channels, the maximum aperture of each subarray is determined according to the above formula 1.

[0021] Preferably, the method of determining the maximum aperture of each subarray according to the above formula 1 based on the requirements of spatial resolution, subarray frequency range and number of available channels includes:

[0022] When the selected subarrays are equally spaced, the spacing of each subarray is set to a multiple relationship to achieve nesting, and when the dominant optimal frequency of each subarray is also set to a multiple relationship, the spatial resolution can be kept unchanged;

[0023] When the selected subarray formation is a multi-arm spiral structure, the maximum aperture of each subarray should be adapted to the variation rule of the aperture in a single array to achieve nesting.

[0024] Preferably, the maximum aperture of each sub-array should be compatible with the variation rule of the aperture in a single array, specifically satisfying:

[0025] When the multi-arm spiral formation of equal ring area is selected as the reference formation, the description of a single formation is as follows:

[0026] r m,1 =r0,m=1,...,N a

[0027]

[0028]

[0029] In the formula, (r m,n ,θ m,n ) is the microphone coordinates of the plane array in the polar coordinate system, N a is the number of spiral arms, N m is the number of microphones on each spiral arm, ν is the spiral angle, r0 and r max are the minimum and maximum apertures of this array, respectively.

[0030] You can design the r of each sub-array max There are the following relationships:

[0031]

[0032] Among them, the superscripts represent different subarrays, and N is selected r =15, then the microphones on the 5-layer aperture in the larger aperture subarray can be accurately reused in the smaller array at the next level, that is:

[0033]

[0034]

[0035] Furthermore, when determining r0, it can also be selected arbitrarily from the optional apertures of the next level or even the next level, so that it can also be reused;

[0036] For other forms of multi-arm spiral arrays, the nested design is also performed according to the above logic;

[0037] After confirming the aperture distribution of all sub-arrays at all levels, determine the number of microphones distributed circumferentially on each circle of aperture according to the total number of available microphones, and give the phase angles of all microphone positions;

[0038] The initial spiral angles of sub-arrays at different levels should be adjusted accordingly, and the whole array should be rotated to achieve precise position matching and multiplexing.

[0039] Preferably, the circumferential distribution rule of the subarrays in S2 is obtained according to the subarray formation form and nesting rules.

[0040] Preferably, the subarray weight function optimization and the maximum gain function are implemented in S3, wherein the subarray weight function optimization includes:

[0041] The weight function of the array signal consists of two parts.

[0042] w n =λ n μ n (Formula 5)

[0043] λ n is the weight function for correcting the microphone distribution density, μ n is a correction to the effective aperture of the array, which is frequency dependent;

[0044] Equation 5 can be further assumed to be in the following functional form:

[0045] λ n =ρ n α(f)

[0046] μ n =erfc(2×[β(f)ρ n -1] (Formula 6)

[0047] Where: n =r n / r max , α and β are coefficients related to frequency f, which can control the microphone distribution density and effective aperture. The optimized weight function can effectively control the main lobe width of the positioning result, that is, the spatial resolution;

[0048] At lower frequencies, the microphone weight on the central aperture is reduced, while at higher frequencies, the microphone weight on the outer aperture is reduced, which in turn reduces the effective aperture.

[0049] Preferably, the subarray weight function optimization and the maximum gain function are implemented in S3, wherein the maximum gain function optimization process includes:

[0050] Define the array gain function G as the optimization objective function,

[0051]

[0052] In the formula, w n is the weight function defined in Formula 5;

[0053] The objective function in Equation 7 reflects the ratio of the overall signal-to-noise ratio of the array to the signal-to-noise ratio of a single microphone. Since the correlation loss between different microphones is one of the main sources of signal interference, the nonlinear optimization problem is determined as follows:

[0054]

[0055] sB 3dB =B c

[0056] B 10dB ≤2B c

[0057] α≥0. (Equation 8)

[0058] Where G(w) is the gain function defined in Equation 7, and B 3dB B is the width of the main lobe within 3dB of the main lobe peak. 10dB B is the width of the main lobe within 10 dB of the main lobe peak. c is the target main lobe width at a given frequency, representing the required array resolution requirement, and α is the coefficient defined in Equation 6;

[0059] By giving the resolution constraint within the target frequency range, the optimal coefficients of each subarray are confirmed through nonlinear optimization, and the optimized maximum gain value within all target frequency ranges is obtained. The gain function reaches the maximum value at the frequency that is compatible with the array aperture and density distribution, and continuously decreases at other frequencies.

[0060] If the gain functions of a plurality of different nested sub-arrays have different selectivities with respect to the distribution of frequencies, a gain threshold is set, and the sub-array is utilized only when the gain is above the threshold.

[0061] The present invention also discloses a self-similar multi-aperture nested microphone array design system, using any of the above methods, the system comprising:

[0062] The subarray radial aperture distribution acquisition module is used to confirm the aperture distribution of microphones in all arrays, so that the apertures in the large array can be reused in the subarray without changing the formation, and obtain the subarray radial aperture distribution;

[0063] The module for obtaining the formation arrangement of each array and the total formation arrangement after nesting is used to obtain the formation arrangement of each array and the total formation arrangement after nesting according to the subarray radial aperture distribution and the subarray circumferential distribution rule obtained by the subarray radial aperture distribution obtaining module;

[0064] The subarray weight function and maximum gain function optimization module is used to optimize the subarray weight function and the maximum gain function according to the specified target resolution constraint requirements and the array array arrangement and the total array arrangement after nesting obtained by the array array arrangement and the total array arrangement after nesting acquisition module;

[0065] The module for obtaining the applicable frequency range of each subarray and the optimized weight function coefficient of each frequency subarray is used to obtain the applicable frequency range of each subarray and the optimized weight function coefficient of each frequency subarray according to the subarray weight function and maximum gain function optimized by the module for optimizing the subarray weight function and the maximum gain function, combined with the specified gain function threshold.

[0066] The present invention also discloses a terminal, including a processor and a storage medium;

[0067] The storage medium is used to store instructions;

[0068] The processor is used to operate according to the instructions to execute the steps of any of the methods described above.

[0069] The present invention also discloses a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of any of the above methods are implemented.

[0070] The present invention has the following beneficial effects:

[0071] The present invention provides a self-similar multi-aperture nested microphone array design method and system, which realizes the precise self-similarity of each sub-array, has simple and clear nesting rules, and can more clearly and simply confirm the frequency applicable range of each sub-array by optimizing the microphone channel weight function, while ensuring a high dynamic range performance.

[0072] The present invention utilizes the weight optimization technology in single array optimization to determine the frequency applicable range of multiple nested arrays, getting rid of the interference of human subjective experience factors, not only realizing the continuous controllable resolution of all sub-arrays, but also ensuring the overall better dynamic range within the target design frequency range. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 It is a schematic diagram of the subarray distribution of the QTD2 project in the background technology.

[0074] Figure 2 It is a schematic diagram of the subarray distribution of the QTD3 project in the background technology.

[0075] Figure 3 It is a schematic diagram of the sub-array frequency division of the QTD3 project in the background technology.

[0076] Figure 4 A schematic diagram of the flow of a self-similar multi-aperture nested microphone array design method of the present invention.

[0077] Figure 5 This is an example of a self-similar multi-aperture nested array of a self-similar multi-aperture nested microphone array design method of the present invention.

[0078] Figure 6 A schematic diagram of the resolution of a self-similar multi-aperture nested array of a self-similar multi-aperture nested microphone array design method of the present invention.

[0079] Figure 7 It is a schematic diagram of the maximum gain of each array after the weight coefficient of the self-similar multi-aperture nested microphone array design method of the present invention is optimized. DETAILED DESCRIPTION

[0080] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0081] See also Figure 4 , a self-similar multi-aperture nested microphone array design method, the method comprising the following steps:

[0082] S1, confirm the aperture distribution of microphones in all arrays, so that the apertures in the large array can be reused in the sub-array without changing the array, and obtain the radial aperture distribution of the sub-array;

[0083] S2, according to the sub-array radial aperture distribution and sub-array circumferential distribution rules obtained in S1, obtain the array formation arrangement of each array and the total array arrangement after nesting;

[0084] S3, according to the specified target resolution constraint requirements and the array formation arrangement obtained in S2 and the total array formation arrangement after nesting, realize subarray weight function optimization and maximum gain function optimization;

[0085] S4: According to the subarray weight function and the maximum gain function optimized in S3, combined with the specified gain function threshold, the applicable frequency range of each subarray and the optimized weight function coefficient of each frequency subarray are obtained.

[0086] In specific implementation, the design constraints of the radial aperture distribution of the subarray in S1 include:

[0087] Subarray frequency range, resolution, dynamic range, number of microphones, and subarray formation and nesting rules.

[0088] In a specific implementation, the step of confirming in S1 that the aperture distribution method of all microphones in the array is a planar beamforming method includes:

[0089] For the planar beamforming method, the spatial resolution is related to the source frequency, the source plane distance, and the aperture size as follows:

[0090]

[0091] In the formula, A is an empirical constant, Y is the distance between the array scanning plane and the sound source plane, D is the array aperture, and f is the sound source frequency;

[0092] According to the requirements of spatial resolution, subarray frequency range and number of available channels, the maximum aperture of each subarray is determined according to the above formula 1.

[0093] In a specific implementation, the method for determining the maximum aperture of each subarray according to the above formula 1 based on the requirements of spatial resolution, subarray frequency range and number of available channels includes:

[0094] When the selected subarrays are equally spaced, the spacing of each subarray is set to a multiple relationship to achieve nesting, and when the dominant optimal frequency of each subarray is also set to a multiple relationship, the spatial resolution can be kept unchanged;

[0095] When the selected subarray formation is a multi-arm spiral structure, the maximum aperture of each subarray should be adapted to the variation rule of the aperture in a single array to achieve nesting.

[0096] In specific implementation, the maximum aperture of each sub-array should be adapted to the variation rule of the aperture in a single array, specifically satisfying:

[0097] When the multi-arm spiral formation (Underbrink) of equal ring area is selected as the reference formation, the description of a single formation is as follows:

[0098] r m,1 =r0,m=1,...,N a

[0099]

[0100]

[0101] In the formula, (r m,n ,θ m,n) is the microphone coordinates of the plane array in the polar coordinate system, N a is the number of spiral arms, N m is the number of microphones on each spiral arm, ν is the spiral angle, r0 and r max are the minimum and maximum apertures of this array, respectively;

[0102] You can design the r of each sub-array max There are the following relationships:

[0103]

[0104] Among them, the superscripts represent different subarrays, and N is selected r =15, then the microphones on the 5-layer aperture in the larger aperture subarray can be accurately reused in the smaller array at the next level, that is:

[0105]

[0106]

[0107] Furthermore, when determining r0, it can also be selected arbitrarily from the optional apertures of the next level or even the next level, so that it can also be reused, for example

[0108] For other forms of multi-arm spiral arrays, the aperture changes in different ways, but the nested design is also performed according to the above logic;

[0109] After confirming the aperture distribution of all sub-arrays at all levels, determine the number of microphones distributed circumferentially on each circle of aperture according to the total number of available microphones, and give the phase angles of all microphone positions;

[0110] The initial spiral angles of sub-arrays at different levels should be adjusted accordingly, and the whole array should be rotated to achieve precise position matching and multiplexing.

[0111] In specific implementation, the circumferential distribution rule of the subarrays in S2 is obtained according to the subarray formation form and nesting rules.

[0112] In specific implementation, the subarray weight function optimization and the maximum gain function are implemented in S3, wherein the subarray weight function optimization includes:

[0113] The weight function of the array signal consists of two parts.

[0114] w n =λ n μ n (Formula 5)

[0115] λ n is the weight function for correcting the microphone distribution density, μ nis a correction to the effective aperture of the array, which is frequency dependent;

[0116] Equation 5 can be further assumed to be in the following functional form:

[0117] λ n =ρ n α(f)

[0118] μ n =erfc(2×[β(f)ρ n -1] (Formula 6)

[0119] Where: n =r n / r max , α and β are coefficients related to frequency f, which can control the microphone distribution density and effective aperture. The optimized weight function can effectively control the main lobe width of the positioning result, that is, the spatial resolution;

[0120] At lower frequencies, the microphone weight on the central aperture is reduced, while at higher frequencies, the microphone weight on the outer aperture is reduced, which in turn reduces the effective aperture.

[0121] In specific implementation, the subarray weight function optimization and the maximum gain function are implemented in S3, wherein the maximum gain function optimization process includes:

[0122] Define the array gain function G as the optimization objective function,

[0123]

[0124] In the formula, w n is the weight function defined by formula 5;

[0125] The objective function in Equation 7 reflects the ratio of the overall signal-to-noise ratio of the array to the signal-to-noise ratio of a single microphone. Since the correlation loss between different microphones is one of the main sources of signal interference, the nonlinear optimization problem is determined as follows:

[0126]

[0127] sB 3dB =B c

[0128] B 10dB ≤2B c

[0129] α≥0. (Equation 8)

[0130] Where G(w) is the gain function defined in Equation 7, and B 3dB B is the width of the main lobe within 3dB of the main lobe peak. 10dBB is the width of the main lobe within 10 dB of the main lobe peak. c is the target main lobe width at a given frequency, representing the required array resolution requirement, and α is the coefficient defined in Equation 6;

[0131] By giving the resolution constraint within the target frequency range, the optimal coefficients of each subarray are confirmed through nonlinear optimization, and the optimized maximum gain value within all target frequency ranges is obtained. The gain function reaches the maximum value at the frequency that is compatible with the array aperture and density distribution, and continuously decreases at other frequencies.

[0132] If the gain functions of a plurality of different nested sub-arrays have different selectivities with respect to the distribution of frequencies, a gain threshold is set, and the sub-array is utilized only when the gain is above the threshold.

[0133] In order to further illustrate the design process, we only take the design of a three-layer nested array as an example, and select the Underbrink multi-arm spiral formation as the basis for nested design. r =15,N m =6, the maximum aperture diameter is 3.6 meters, the number of channels in each subarray is 90, and the final design array channel number is 204. The final formation is as follows Figure 5 As shown, the three sub-array formations are completely self-similar. Figure 5 The solid lines in the middle are the maximum aperture marks of the three sub-arrays, and the overlapping parts of the star marks, square marks, and cross marks represent the multiplexing of the same microphone on multiple different sub-arrays.

[0134] Figure 6 The spatial resolution of the example nested array is given. When the sound source plane is 7 meters away from the array, the 3dB main lobe width of the point sound source localization result is as follows: Figure 6 As shown by the blue line. In order to optimize the gain function, for the design frequency range of 2500Hz to 25000Hz, the target resolution constraint is set as shown by the red dotted line, and finally the optimized weight coefficient and gain value of each sub-array are obtained. The change of the array gain with frequency after optimization is shown in Figure 7 As shown in the figure, it can be seen that due to the difference in the maximum aperture of each sub-array, the frequency of the maximum gain value is different. This frequency distribution diagram has a strong correlation with the slope of the target resolution curve. The distribution of the maximum gain value can even be further adjusted by changing the target resolution curve.

[0135] According to the total number of channels and resolution settings given in this example, selecting 60 as the gain threshold can well divide the applicable frequency range of different nested arrays. The frequency range of the outer larger aperture subarray is about 2500-5400Hz, the frequency range of the middle aperture subarray is 5500-12000Hz, and the frequency range of the innermost subarray is 12000-30000Hz, thus covering the entire required target frequency range while maintaining a high array gain, and each subarray formation is strictly self-similar, so it is expected to obtain better post-processing analysis results.

[0136] The present invention also discloses a self-similar multi-aperture nested microphone array design system, using any of the above methods, the system comprising:

[0137] The subarray radial aperture distribution acquisition module is used to confirm the aperture distribution of microphones in all arrays, so that the apertures in the large array can be reused in the subarray without changing the formation, and obtain the subarray radial aperture distribution;

[0138] The module for obtaining the formation arrangement of each array and the total formation arrangement after nesting is used to obtain the formation arrangement of each array and the total formation arrangement after nesting according to the subarray radial aperture distribution and the subarray circumferential distribution rule obtained by the subarray radial aperture distribution obtaining module;

[0139] The subarray weight function and maximum gain function optimization module is used to optimize the subarray weight function and the maximum gain function according to the specified target resolution constraint requirements and the array array arrangement and the total array arrangement after nesting obtained by the array array arrangement and the total array arrangement after nesting acquisition module;

[0140] The module for obtaining the applicable frequency range of each subarray and the optimized weight function coefficient of each frequency subarray is used to obtain the applicable frequency range of each subarray and the optimized weight function coefficient of each frequency subarray according to the subarray weight function and maximum gain function optimized by the module for optimizing the subarray weight function and the maximum gain function, combined with the specified gain function threshold.

[0141] The present invention also discloses a terminal, including a processor and a storage medium;

[0142] The storage medium is used to store instructions;

[0143] The processor is used to operate according to the instructions to execute the steps of any of the methods described above.

[0144] The present invention also discloses a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of any of the above methods are implemented.

[0145] The present invention provides a self-similar multi-aperture nested microphone array design method and system, which realizes the precise self-similarity of each sub-array, has simple and clear nesting rules, and can more clearly and simply confirm the frequency applicable range of each sub-array by optimizing the microphone channel weight function, while ensuring a high dynamic range performance.

[0146] The present invention utilizes the weight optimization technology in single array optimization to determine the frequency applicable range of multiple nested arrays, getting rid of the interference of human subjective experience factors, not only realizing the continuous controllable resolution of all sub-arrays, but also ensuring the overall better dynamic range within the target design frequency range.

[0147] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, these modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A self-similar multi-aperture nested microphone array design method, characterized by: The method comprises the following steps: S1, confirm the aperture distribution of microphones in all arrays, so that the apertures in the large array can be reused in the sub-array without changing the array, and obtain the radial aperture distribution of the sub-array; S2, according to the sub-array radial aperture distribution and sub-array circumferential distribution rules obtained in S1, obtain the array formation arrangement of each array and the total array arrangement after nesting; S3, according to the specified target resolution constraint requirements and the array formation arrangement obtained in S2 and the total array formation arrangement after nesting, realize subarray weight function optimization and maximum gain function optimization; S4: According to the subarray weight function and the maximum gain function optimized in S3, combined with the specified gain function threshold, the applicable frequency range of each subarray and the optimized weight function coefficient of each frequency subarray are obtained.

2. A self-similar multi-aperture nested microphone array design method according to claim 1, characterized in that: The design constraints of the radial aperture distribution of the S1 neutron array include: Subarray frequency range, resolution, dynamic range, number of microphones, and subarray formation and nesting rules.

3. The method for designing a self-similar multi-aperture nested microphone array according to claim 1, characterized in that: The S1 confirms that the microphone aperture distribution method in all arrays is a planar beamforming method, including: For the planar beamforming method, the spatial resolution is related to the source frequency, the source plane distance, and the aperture size as follows: In the formula, A is an empirical constant, Y is the distance between the array scanning plane and the sound source plane, D is the array aperture, and f is the sound source frequency; According to the requirements of spatial resolution, subarray frequency range and number of available channels, the maximum aperture of each subarray is determined according to the above formula 1.

4. The method for designing a self-similar multi-aperture nested microphone array according to claim 3, characterized in that: The method for determining the maximum aperture of each subarray according to the above formula 1 based on the requirements of spatial resolution, subarray frequency range and number of available channels includes: When the selected subarrays are equally spaced, the spacing of each subarray is set to a multiple relationship to achieve nesting, and when the dominant optimal frequency of each subarray is also set to a multiple relationship, the spatial resolution can be kept unchanged; When the selected subarray formation is a multi-arm spiral structure, the maximum aperture of each subarray should be adapted to the variation rule of the aperture in a single array to achieve nesting.

5. The method for designing a self-similar multi-aperture nested microphone array according to claim 4, characterized in that: The maximum aperture of each sub-array should be compatible with the variation law of the aperture in a single array, specifically satisfying: When the multi-arm spiral formation of equal ring area is selected as the reference formation, the description of a single formation is as follows: In the formula, (r m,n ,θ m,n ) is the microphone coordinates of the plane array in the polar coordinate system, N a is the number of spiral arms, N m is the number of microphones on each spiral arm, ν is the spiral angle, r0 and r max are the minimum and maximum apertures of the array respectively; r of each subarray can be designed max There are the following relationships: Among them, the superscripts represent different subarrays, and N is selected m =15, then the microphones on the 5-layer aperture in the larger aperture subarray can be accurately reused in the smaller array at the next level, that is: Furthermore, when determining r0, it can also be selected arbitrarily from the optional apertures of the next level or even the next level, so that it can also be reused; For other forms of multi-arm spiral arrays, the nested design is also performed according to the above logic; After confirming the aperture distribution of all sub-arrays at all levels, determine the number of microphones distributed circumferentially on each circle of aperture according to the total number of available microphones, and give the phase angles of all microphone positions; The initial spiral angles of sub-arrays at different levels should be adjusted accordingly, and the whole array should be rotated to achieve precise position matching and multiplexing.

6. The method for designing a self-similar multi-aperture nested microphone array according to claim 1, characterized in that: The circumferential distribution rule of the subarrays in S2 is obtained according to the subarray formation form and nesting rules.

7. The method for designing a self-similar multi-aperture nested microphone array according to claim 1, characterized in that: In S3, subarray weight function optimization and maximum gain function are implemented, wherein subarray weight function optimization includes: The weight function of the array signal consists of two parts. w n =λ n m n (formula 5) λ n is the weight function for correcting the microphone distribution density, μ n is a correction to the effective aperture of the array, which is frequency dependent; Equation 5 can be further assumed to be in the following functional form: l n =ρ n α(f) μ n = erfc(2 × [β(f)ρ n -1] (Equation 6) Where: n =r n / r max , α and β are coefficients related to frequency f, which can control the microphone distribution density and effective aperture. The optimized weight function can effectively control the main lobe width of the positioning result, that is, the spatial resolution; At lower frequencies, the microphone weight on the central aperture is reduced, while at higher frequencies, the microphone weight on the outer aperture is reduced, which in turn reduces the effective aperture.

8. The method for designing a self-similar multi-aperture nested microphone array according to claim 1, characterized in that: In S3, subarray weight function optimization and maximum gain function are implemented, wherein the maximum gain function optimization process includes: Define the array gain function G as the optimization objective function, In the formula, w n is the weight function defined in Formula 5; the objective function in Formula 7 reflects the ratio of the overall signal-to-noise ratio of the array to the signal-to-noise ratio of a single microphone. Since the correlation loss between different microphones is one of the main sources of signal interference, the nonlinear optimization problem is determined as follows: s.t.B 3dB =B c B 10dB ≤2B c α≥0. (Equation 8) Where G(w) is the gain function defined in Equation 7, and B 3dB B is the width of the main lobe within 3dB of the main lobe peak. 10dB B is the width of the main lobe within 10 dB of the main lobe peak. c is the target main lobe width at a given frequency, representing the required array resolution requirement, and α is the coefficient defined in Equation 6; By giving the resolution constraint within the target frequency range, the optimal coefficients of each subarray are confirmed through nonlinear optimization, and the optimized maximum gain value within all target frequency ranges is obtained. The gain function reaches the maximum value at the frequency that is compatible with the array aperture and density distribution, and continuously decreases at other frequencies. If the gain functions of a plurality of different nested sub-arrays have different selectivities with respect to the distribution of frequencies, a gain threshold is set, and the sub-array is utilized only when the gain is above the threshold.

9. A self-similar multi-aperture nested microphone array design system, using the method according to any one of claims 1 to 7, characterized in that: The system comprises: The subarray radial aperture distribution acquisition module is used to confirm the aperture distribution of microphones in all arrays, so that the apertures in the large array can be reused in the subarray without changing the formation, and obtain the subarray radial aperture distribution; The module for obtaining the formation arrangement of each array and the total formation arrangement after nesting is used to obtain the formation arrangement of each array and the total formation arrangement after nesting according to the subarray radial aperture distribution and the subarray circumferential distribution rule obtained by the subarray radial aperture distribution obtaining module; The subarray weight function and maximum gain function optimization module is used to optimize the subarray weight function and the maximum gain function according to the specified target resolution constraint requirements and the array array arrangement and the total array arrangement after nesting obtained by the array array arrangement and the total array arrangement after nesting acquisition module; The module for obtaining the applicable frequency range of each subarray and the optimized weight function coefficient of each frequency subarray is used to obtain the applicable frequency range of each subarray and the optimized weight function coefficient of each frequency subarray according to the subarray weight function and maximum gain function optimized by the module for optimizing the subarray weight function and the maximum gain function, combined with the specified gain function threshold.

10. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 7.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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