An internal seven-directional arrangement silicon microphone underwater seismic source monitoring device and method

Abstract

The application relates to an underwater seismic source monitoring device of an internal seven-direction arrangement silicon microphone, which comprises an internal seven-direction silicon microphone device, a multi-channel acquisition system, an underwater seismic source simulation system and a data processing system; the internal seven-direction silicon microphone device comprises an internal seven-direction support and seven silicon microphones fixed on the internal seven-direction support; a recess is arranged on the inner side wall of the internal seven-direction support, the recess comprises a hexagonal bottom surface and six inclined surfaces arranged around the hexagonal bottom surface, one silicon microphone is fixed on the hexagonal bottom surface, and one silicon microphone is fixed on each of the six inclined surfaces. The seven silicon microphones are arranged in a specific arrangement mode, can be conveniently installed on underwater equipment to collect sound signals, the collected sound signals can be used to accurately calculate specific coordinate points of a simulation seismic source and the main wave transmission direction of the simulation seismic source, and a peak value detection algorithm is adopted to analyze the distribution and evolution law of different events in the underwater seismic source simulation experiment process.

Description

Technical Field

[0001] The present invention belongs to the technical field of underwater acoustic signal monitoring, and in particular relates to an underwater earthquake source monitoring device and method with silicon microphones arranged in seven directions inside. Background Art

[0002] Acoustic signals are the signals with the longest transmission distance underwater and are the most valuable for analysis and use. Therefore, the monitoring and analysis of underwater acoustic signals is particularly important. Underwater acoustic signal monitoring technology can monitor and analyze the distribution and evolution of effective events generated during underwater vibrations, and plays an important role in many fields such as the operation of underwater facilities, underwater resource exploitation, underwater natural disasters, and underwater blasting engineering. However, underwater acoustic signal monitoring equipment is usually arranged in a linear array. Linear array devices have poor anti-interference capabilities, uneven angular resolution, poor resolution of depth information of sound sources, and do not take into account changes in signal reception angles. Therefore, it is necessary to design a multi-angle, nonlinear array underwater acoustic signal monitoring device. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the deficiencies in the above-mentioned prior art and to provide an underwater earthquake source monitoring device and method with silicon microphones arranged in seven directions internally. The silicon microphones have high integration, small size, and light weight, and are easy to install at various positions of underwater equipment for monitoring. The sound signals generated during underwater vibration are monitored by the silicon microphone device arranged in seven directions internally, and the specific location of the earthquake source can be calculated using the arrival time difference algorithm. The beamforming algorithm is used to calculate the main wave transmission direction of the simulated earthquake source, and the dynamic time bending algorithm is used to automatically align the voltage-time curve with the strain-time curve and the acceleration-time curve. The peak detection algorithm is used to analyze the distribution and evolution laws of different events during the underwater earthquake source simulation experiment.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is:

[0005] An underwater earthquake source monitoring device with silicon microphones arranged in seven directions internally, comprising an internal seven-directional silicon microphone device, a multi-channel acquisition system, an underwater earthquake source simulation system and a data processing system; the internal seven-directional silicon microphone device comprises an internal seven-directional bracket and seven silicon microphones fixed on the internal seven-directional bracket; the inner side wall of the internal seven-directional bracket is provided with a groove, the groove comprises a hexagonal bottom surface, and six inclined surfaces arranged around the hexagonal bottom surface, a silicon microphone is fixed on the hexagonal bottom surface, and a silicon microphone is fixed on each of the six inclined surfaces; the multi-channel acquisition system is respectively connected to the seven silicon microphones for signal acquisition to acquire the sound signals generated during the underwater earthquake source simulation experiment collected by the seven silicon microphones, and transmits the sound signals to the data processing system; the underwater earthquake source simulation system comprises a water bucket, an underwater earthquake source simulation device and an underwater earthquake source monitoring device, the water bucket is used to simulate the underwater environment, the internal seven-directional bracket is provided with a groove, the groove comprises a hexagonal bottom surface, and six inclined surfaces arranged around the hexagonal bottom surface, a silicon microphone is fixed on the hexagonal bottom surface, and a silicon microphone is fixed on each of the six inclined surfaces; the multi-channel acquisition system is respectively connected to the seven silicon microphones for signal acquisition to acquire the sound signals generated during the underwater earthquake source simulation experiment collected by the seven silicon microphones, and transmits the sound signals to the data processing system, The silicon microphone device is fixed to the inner wall of the bucket, the underwater seismic source simulation equipment is used to simulate underwater blasting or vibration events, and the underwater seismic source monitoring equipment includes a strain gauge, an accelerometer probe and a monitoring device. The strain gauge and the accelerometer probe are installed on the outer wall of the bucket and are respectively connected to the monitoring device for signal connection. The monitoring device transmits the monitored strain signal and acceleration signal to the data processing system; the data processing system plots the collected sound signal into a voltage-time curve, the strain signal into a strain-time curve, and the acceleration signal into an acceleration-time curve, and uses a dynamic time bending algorithm to automatically align the voltage-time curve with the strain-time curve and the acceleration-time curve, uses a peak detection algorithm to analyze the distribution and evolution laws of different events during the underwater seismic source simulation experiment, uses an arrival time difference algorithm to calculate the coordinates of the seismic source, and uses a beamforming algorithm to calculate the main wave transmission direction of the simulated seismic source.

[0006] In the above scheme, the sampling surface of the silicon microphone fixed on the bottom surface of the hexagon faces the direction of the target sampling signal, and the angles between the sampling surfaces of the six silicon microphones fixed on the inclined surface of the groove and the bottom surface of the hexagon are 30° to 60°, and the angles between the six sampling surfaces and the bottom surface of the hexagon are equal.

[0007] In the above scheme, the silicon microphones fixed to the hexagonal bottom are located at the same horizontal height as the geometric center of the bucket.

[0008] In the above scheme, the seven silicon microphones are all omnidirectional silicon microphones, the frequency range of collecting sound signals is 50 to 20,000 Hz, and the sensitivity is -22 to -62 dB.

[0009] In the above solution, the multi-channel acquisition system is an eight-channel acquisition instrument, and the sampling frequency range is set to 20 to 100 kHz.

[0010] In the above scheme, the underwater seismic source simulation equipment includes a long-delay explosive and an explosive detonation system. The long-delay explosive is placed at the geometric center of the water bucket, and the explosive detonation system is placed outside the water bucket. The two are connected by a wire, and the explosive detonation system is used to detonate the long-delay explosive to simulate underwater blasting or vibration events.

[0011] In the above solution, the strain gauge, accelerometer probe and the internal seven-directional silicon microphone device are at the same level, and the distances between the three are equal.

[0012] Accordingly, the present invention further proposes an underwater earthquake source monitoring method, which uses the above-mentioned silicon microphone device arranged in seven directions internally. The underwater earthquake source monitoring method includes the following steps:

[0013] S1. Install the silicon microphone device arranged in seven directions inside according to the design requirements;

[0014] S2. Calibrate the sound source localization effect of the internal seven-directional silicon microphone device using a lead-breaking experiment;

[0015] S3. Setting the detonation time of the explosive detonation system. After detonation, the voltage-time data collected by the multi-channel acquisition system and the strain-time data and acceleration-time data collected by the underwater seismic source monitoring equipment are input into the data processing system.

[0016] S4. The data processing system uses a dynamic time bending algorithm to automatically align the voltage-time curve with the strain-time curve and the acceleration-time curve. The three types of aligned curves are then analyzed using a peak detection algorithm to analyze the distribution and evolution of different events during the underwater earthquake source simulation experiment. The arrival time difference algorithm is used to calculate the coordinates of the earthquake source, and the beamforming algorithm is used to determine the transmission direction of the main wave of the earthquake source.

[0017] In the above method, the method of calibrating the sound source localization effect of the internal seven-directional silicon microphone device using the lead-breaking experiment in step S2 includes:

[0018] S2.1. Extend a lead of a certain diameter to a certain length, with the lead forming a certain angle with the outer wall of the bucket. Break the lead at different locations on the outer wall of the bucket. Repeat the experiment multiple times at each break location.

[0019] S2.2. Use a multi-channel acquisition system to collect the sound signal generated by the lead breaking experiment and input the collected voltage-time data into the data processing system;

[0020] S2.3. The data processing system processes the collected voltage-time data to ensure that the error between the coordinates calculated from the sound source positioning of the lead break point and the actual lead break point coordinates does not exceed a certain threshold, and the calibration is considered to be successful.

[0021] In the above method, the coordinates of the lead-break position calculated by the sound source location are calculated by formula (1), which is as follows:

[0022]

[0023] In formula (1), c is the speed of the acoustic signal propagating underwater, t i ' is the time point when the i-th silicon microphone receives the lead-break sound signal, (x i ,y i , z i ) are the coordinates of the i-th silicon microphone, i = 1 to 7, t0' is the time point when the broken lead vibrates, and (x', y', z') are the coordinates of the broken lead site;

[0024] Compare the coordinates calculated by formula (1) with the actual lead-breaking point coordinates to ensure that the error between the calculated lead-breaking point coordinates and the actual lead-breaking point coordinates is less than 5%. If it is less than 5%, the calibration is considered to be passed and the subsequent steps can be carried out. If it is not satisfied, readjust the c value until the error is less than 5%.

[0025] In the above method, in step S4, the coordinates of the earthquake source are calculated using the arrival time difference algorithm, specifically according to formula (2):

[0026]

[0027] In formula (2), c is the speed of the acoustic signal propagating underwater, which is determined by the sound source localization effect of the lead experiment calibration in step S2; t i is the time point when the i-th silicon microphone receives the source sound signal, (x i ,y i , z i ) are the coordinates of the i-th silicon microphone, i=1~7, and (x, y, z) are the coordinates of the source.

[0028] In the above method, when the arrival time difference algorithm is used to calculate the coordinates of the earthquake source, the first silicon microphone located on the bottom surface is selected, and four silicon microphones are arbitrarily selected from the six silicon microphones on the inclined surface. The coordinates of these five silicon microphones are substituted into formula (2) to determine the coordinate points (x, y, z) of the simulated earthquake source; the coordinates of the remaining two silicon microphones are substituted into formula (2) to verify the correctness of the calculated earthquake source coordinate points.

[0029] In the above method, in step S4, a beamforming algorithm is used to determine the main wave transmission direction of the earthquake source. Specifically, the main wave transmission direction of the earthquake source is determined by formula (3), which is as follows:

[0030]

[0031] In formula (3), For sound signals The beamforming strength in the direction, θ is the horizontal angle of the source, and the value range is (0,2π). is the vertical angle of the earthquake source, ranging from (0,π), ω i (θ,φ) is the value of the i-th silicon microphone at The weight of the direction, x i (t) is the time domain signal received by the i-th silicon microphone, i = 2 to 7;

[0032] Substituting the beamforming intensities and weights of the six silicon microphones on the six inclined planes into formula (3) can draw the beamforming intensity distribution diagram and obtain the main wave transmission distribution of the simulated earthquake source.

[0033] The beneficial effects of the present invention are:

[0034] 1. This invention arranges seven silicon microphones in a specific pattern within an internal seven-directional bracket, making it easy to install on underwater equipment to collect acoustic signals. The acoustic signals collected by the seven-directional silicon microphones can be combined with a time difference of arrival algorithm to more accurately calculate the specific coordinates of the simulated earthquake source. A beamforming algorithm is used to calculate the propagation direction of the primary wave of the simulated earthquake source. A dynamic time warping algorithm is used to automatically align the voltage-time curve with the strain-time curve and the acceleration-time curve. A peak detection algorithm is then used to analyze the distribution and evolution of different events during underwater earthquake source simulation experiments. Therefore, this invention enables the calculation of the earthquake source location, the propagation direction of the primary wave, and the monitoring of the distribution and evolution of effective events during underwater vibration. Compared to acoustic signal monitoring equipment arranged in a linear array, the seven-directional silicon microphone arrangement of this invention offers advantages such as strong anti-interference capabilities, uniform angular resolution, and more accurate depth resolution of the sound source. Furthermore, the hexagonal arrangement of the silicon microphone array takes into account variations in signal reception angle and can determine the propagation direction of the primary wave.

[0035] 2. Silicon microphones are highly integrated, small in size, and lightweight, making them easy to install at various locations on underwater equipment for monitoring. At the same time, silicon microphones have built-in suppression circuits that can reduce interference from other electromagnetic waves to obtain high-quality underwater sound signals. Furthermore, silicon microphones have low power consumption, are waterproof, and can operate stably and continuously in underwater environments for long periods of time. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0037] Figure 1This is a diagram showing the overall structure of the underwater earthquake source monitoring device with silicon microphones arranged in seven directions, and an enlarged diagram of the structure of the seven-directional silicon microphone device is shown in the figure;

[0038] Figure 2 This is a three-dimensional image of the internal seven-directional silicon microphone device;

[0039] Figure 3 is a flow chart of the underwater earthquake source monitoring method proposed by the present invention;

[0040] Figure 4 This is a graph of data obtained from the first to fifth silicon microphones in an embodiment of the present invention.

[0041] In the figure: 1. Internal seven-directional silicon microphone device; 11. First silicon microphone; 12. Second silicon microphone; 13. Third silicon microphone; 14. Fourth silicon microphone; 15. Fifth silicon microphone; 16. Sixth silicon microphone; 17. Seventh silicon microphone; 18. Internal seven-directional bracket;

[0042] 2. Multi-channel acquisition system;

[0043] 3. Underwater seismic source simulation system; 31. Water bucket; 321. Long-delay explosive; 322. Explosive detonation system; 331. Strain gauge; 332. Accelerator probe; 333. Monitoring equipment;

[0044] 4. Data processing system;

[0045] 5. Power supply device. DETAILED DESCRIPTION

[0046] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0047] Example 1: Device Example

[0048] like Figure 1-2 As shown, a preferred embodiment of the present invention provides an underwater earthquake source monitoring device with a silicon microphone arranged in seven directions, including an internal seven-directional silicon microphone device 1, a multi-channel acquisition system 2, an underwater earthquake source simulation system 3 and a data processing system 4.

[0049] The internal seven-directional silicon microphone device 1 includes an internal seven-directional support 18 and seven silicon microphones fixed to the support 18: a first silicon microphone 11, a second silicon microphone 12, a third silicon microphone 13, a fourth silicon microphone 14, a fifth silicon microphone 15, a sixth silicon microphone 16, and a seventh silicon microphone 17. The inner sidewall of the internal seven-directional support 18 defines a groove comprising a hexagonal base and six inclined surfaces surrounding the hexagonal base. The first silicon microphone 11 is fixed to the hexagonal base, while the second through seventh silicon microphones are fixed to the six inclined surfaces, respectively. The internal seven-directional silicon microphone device 1 can monitor acoustic signals generated during underwater seismic source simulation experiments. The sampling surface of the first silicon microphone 11 is coplanar with the hexagonal base and faces the direction of the target sampling signal.

[0050] The multi-channel acquisition system 2 is respectively connected to the seven silicon microphones to collect the sound signals generated during the underwater seismic source simulation experiment collected by the seven silicon microphones, and transmits the sound signals to the data processing system 4.

[0051] The underwater seismic source simulation system 3 includes a water bucket 31, an underwater seismic source simulation device, and an underwater seismic source monitoring device. The water bucket 31 is used to simulate an underwater environment. The underwater seismic source simulation device is used to simulate underwater explosions or vibration events. An internal seven-directional silicon microphone device 1 is fixed to the inner wall of the water bucket 31. The underwater seismic source monitoring device includes a strain gauge 331, an accelerometer probe 332, and a monitoring device 333. The strain gauge 331 and accelerometer probe 332 are attached to the outer wall of the water bucket 31 to monitor the strain and acceleration generated during the underwater seismic source simulation experiment. The strain gauge 331 and accelerometer probe 332 are respectively connected to the monitoring device 333 for signal transmission. The monitoring device 333 transmits the monitored strain and acceleration signals to the data processing system 4.

[0052] The data processing system 4 plots the collected sound signal into a voltage-time curve, the strain signal into a strain-time curve, and the acceleration signal into an acceleration-time curve. It uses a dynamic time bending algorithm to automatically align the voltage-time curve with the strain-time curve and the acceleration-time curve. It uses a peak detection algorithm to analyze the distribution and evolution laws of different events during the underwater earthquake source simulation experiment, uses an arrival time difference algorithm to calculate the coordinates of the earthquake source, and uses a beam forming algorithm to calculate the main wave transmission direction of the simulated earthquake source.

[0053] Further optimization has been achieved by aligning the inclined surfaces of the grooves in the internal seven-way bracket 18 with the hexagonal base at angles of 30° to 60°. Each silicon microphone is coplanar with its corresponding mounting surface, forming a regular hexagonal arrangement. Specifically, the sampling surfaces of the second through seventh silicon microphones form angles of 30° to 60° with the hexagonal base, with all six sampling surfaces forming equal angles. This arrangement improves earthquake source location accuracy and reduces interference from ambient noise.

[0054] Further optimization is performed, the silicon microphone fixed to the hexagonal bottom surface, that is, the first silicon microphone 11 is located at the same horizontal height as the geometric center of the bucket 31.

[0055] Further optimization, the seven silicon microphones are all omnidirectional silicon microphones, which can collect sound signals with a frequency of 50 to 20,000 Hz, with a sensitivity of -22 to -62 dB, and are waterproof and can continue to work underwater.

[0056] For further optimization, all seven silicon microphones are fixed with hot melt adhesive.

[0057] Further optimization is performed by adapting the outer wall of the internal seven-directional bracket 18 to the inner wall of the bucket 31 to ensure that the internal seven-directional silicon microphone device 1 can be adhered and fixed to the inner wall of the bucket 31. The internal seven-directional bracket 18 is manufactured by 3D printing. In this embodiment, the bucket 31 is a circular barrel, and the outer wall of the internal seven-directional bracket 18 is a curved surface with a diameter equal to the inner diameter of the barrel.

[0058] After further optimization, the multi-channel acquisition system 2 is an eight-channel acquisition instrument, and the sampling frequency range is set to 20kHz to 100kHz.

[0059] Further optimization, the water bucket 31 is a round barrel made of transparent material (such as acrylic) for easy observation. The inner diameter of the water bucket 31 is 20 to 50 cm and the depth is 50 to 100 cm.

[0060] Further optimization, the underwater seismic source simulation equipment includes a long-delay explosive 321 and an explosive detonation system 322. The long-delay explosive 321 is placed at the geometric center of the water bucket 31, and the explosive detonation system 322 is placed outside the water bucket 31. The two are connected by a wire, and the explosive detonation system 322 is used to detonate the long-delay explosive 321 to simulate underwater blasting and vibration events.

[0061] After further optimization, the mass of the long delay explosive 321 is 0.2g to 1.0g.

[0062] Further optimization is performed, where the strain gauge 331 and the accelerometer probe 332 are at the same level as the internal seven-directional silicon microphone device 1, and the distances between the three are equal, which can eliminate the time delay caused by the different heights of various devices and facilitate the alignment of the three types of curves in the later stage.

[0063] Further optimized, the underwater earthquake source monitoring device with silicon microphones arranged in seven directions internally also includes a power supply device for providing a 1-3V DC regulated power supply to the internal seven-directional silicon microphone device 1.

[0064] The first to seventh silicon microphones are fixed in the grooves of the internal seven-directional bracket 18 using hot melt adhesive. The first to seventh silicon microphones are connected to the multi-channel acquisition system 2 and the power supply device via wires. The internal seven-directional silicon microphone device 1 is adhered and fixed to the inner wall of the water bucket 31, and the first silicon microphone 11 is located at the same horizontal height as the geometric center of the water bucket 31. The long-delay explosive 321 is connected to the explosive detonation system 322 via wires, and the long-delay explosive 321 is fixed at the geometric center of the water bucket 31 filled with water. The strain gauge 331 and the accelerator probe 332 are adhered and fixed to the outer wall of the water bucket 31 and located at the same horizontal height as the geometric center of the water bucket 31. The strain gauge 331 and the accelerator probe 332 are connected to the monitoring device 333 via data cables. The multi-channel acquisition system 2 and the monitoring device 333 are respectively connected to the data processing system 4, thereby forming the underwater seismic source monitoring device with silicon microphones arranged in seven directions internally as described in the present invention.

[0065] Example 2: Method Example

[0066] like Figure 3 As shown, the present invention also proposes an underwater earthquake source monitoring method, which uses the silicon microphone device arranged in seven directions internally in Example 1. The underwater earthquake source monitoring method includes the following steps:

[0067] S1. Install the silicon microphone device with seven internal orientations as described above. Fill a water bucket 31 with water to simulate an underwater environment. Place the bucket 31 in a relatively isolated location, not sharing a platform with other equipment. In this embodiment, the bucket has a diameter of 20 cm and a height of 50 cm. The eight-channel data acquisition device is set to a 20 kHz sampling frequency, the power supply is set to a 2V DC regulated voltage, and the mass of the long-delay explosive 321 is 0.2 g.

[0068] S2. After all circuits are connected, a lead-breaking experiment is performed to calibrate the sound source localization effect of the internal seven-directional silicon microphone device 1. The lead-breaking experiment steps include:

[0069] S2.1. Extend a lead of a certain diameter to a certain length, with the lead forming a certain angle with the outer wall of the bucket 31. Break the lead at different locations on the outer wall of the bucket 31, repeating the experiment multiple times at each breakage location. In this example, the lead is a 0.5 mm diameter HB lead, extending to a length of 2.5 mm, and at a 30° angle with the outer wall of the bucket 31.

[0070] S2.2. Use the multi-channel acquisition system 2 to collect the sound signal generated by the lead breaking experiment, and input the collected voltage-time data into the data processing system 4.

[0071] S2.3, the data processing system 4 processes the collected voltage-time data to ensure that the coordinates of the lead-break point calculated by the sound source positioning do not exceed a certain threshold value with the coordinates of the actual lead-break point, and the calibration is considered to be successful. Specifically, the coordinates of the lead-break point calculated by the sound source positioning are calculated using formula (1), which is as follows:

[0072]

[0073] In formula (1), c is the speed of the acoustic signal propagating underwater, t i ' is the time point when the i-th silicon microphone receives the lead-break sound signal, (x i ,y i , z i ) are the coordinates of the i-th silicon microphone, i=1~7, t0' is the time point when the broken lead vibrates, and (x', y', z') are the coordinates of the broken lead site.

[0074] Compare the coordinates calculated by formula (1) with the actual lead-breaking point coordinates to ensure that the error between the calculated lead-breaking point coordinates and the actual lead-breaking point coordinates is less than 5%. If it is less than 5%, it is considered that the calibration has passed and the subsequent steps can be carried out. If it is not satisfied, readjust the c value to an error of less than 5%.

[0075] S3. The detonation time of explosive detonation system 322 is set. After detonation, the voltage-time data collected by multi-channel acquisition system 2 and the strain-time data and acceleration-time data collected by the underwater seismic source monitoring equipment are input into data processing system 4. In this embodiment, explosive detonation system 322 is set to detonate long-delay explosive 321 after 5 seconds, ensuring safety before detonating long-delay explosive 321.

[0076] S4. Using the dynamic time warping algorithm, the data processing system 4 automatically aligns the voltage-time curve with the strain-time curve and the acceleration-time curve. The peak detection algorithm is then used to analyze the distribution and evolution of different events during the underwater earthquake source simulation experiment. The arrival time difference algorithm is then used to calculate the coordinates of the earthquake source and determine the direction of the main wave propagation. The specific steps are as follows:

[0077] S4.1. In MATLAB, the collected voltage-time signal, strain-time signal, and acceleration-time signal are plotted as curves, and the three types of curves are automatically aligned using the dynamic time warping algorithm (directly calling the DTW function in MATLAB can automatically align the three types of curves).

[0078] S4.2. Use the peak detection algorithm in MATLAB to analyze the distribution and evolution of different events during the underwater earthquake source simulation experiment.

[0079] like Figure 4 As shown, in this embodiment, channels 1 to 5 are the acoustic signals collected by the first to fifth silicon microphones respectively, the horizontal axis is time, and the vertical axis is the collected voltage signal. The first time period is before the simulated earthquake source is generated, the second time period is the process of the simulated earthquake source generation, which lasts for 0.4 seconds, and the energy of the earthquake source gradually decays. The signal fluctuations generated in the third time period are all acoustic signals generated by water surface fluctuations.

[0080] S4.3. Calculate the coordinates of the simulated earthquake source using the time difference of arrival algorithm, specifically according to formula (2):

[0081]

[0082] In formula (2), c is the speed of the acoustic signal propagating underwater, which is determined by the sound source localization effect of the lead experiment calibration in step S2; t i is the time point when the i-th silicon microphone receives the source sound signal, (x i ,y i , z i ) are the coordinates of the i-th silicon microphone, i = 1 to 7, and (x, y, z) are the coordinates of the simulated source.

[0083] In this embodiment, the sampling surfaces of the second to seventh silicon microphones form an angle of 30° with the bottom surface of the hexagon. The coordinates of the first silicon microphone 11 are set as the origin (0,0,0), and the coordinates of the second silicon microphone are The coordinates of the third silicon microphone are The coordinates of the fourth silicon microphone are The coordinates of the fifth silicon microphone are The coordinates of the sixth silicon microphone are The coordinates of the seventh silicon microphone are When the arrival time difference algorithm is used to calculate the coordinates of the earthquake source, the first silicon microphone 11 located on the bottom surface is selected, and four silicon microphones are randomly selected from the six silicon microphones on the inclined surface. The coordinates of these five silicon microphones are substituted into formula (2) to determine the coordinate points of the simulated earthquake source as (0.2, 0.1, 10.2); the coordinates of the remaining two silicon microphones are substituted into formula (2) to verify the correctness of the calculated earthquake source coordinate points.

[0084] S4.4. In step S4, the main wave transmission direction of the earthquake source is determined by formula (3), which is as follows:

[0085]

[0086] In formula (3), For sound signals The beamforming strength in the direction, θ is the horizontal angle of the source, and the value range is (0,2π). is the vertical angle of the earthquake source, ranging from (0,π), ω i (θ,φ) is the value of the i-th silicon microphone at The weight of the direction, x i (t) is the time domain signal received by the i-th silicon microphone, i=2~7.

[0087] Substituting the beamforming intensities and weights of the six silicon microphones on the six inclined planes into formula (3) can draw the beamforming intensity distribution diagram and obtain the main wave transmission distribution of the simulated earthquake source.

[0088] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0089] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. An underwater earthquake source monitoring device with silicon microphones arranged in seven directions, characterized in that: It includes an internal seven-directional silicon microphone device, a multi-channel acquisition system, an underwater seismic source simulation system, and a data processing system; The internal seven-directional silicon microphone device includes an internal seven-directional bracket and seven silicon microphones fixed to the internal seven-directional bracket; the inner side wall of the internal seven-directional bracket is provided with a groove, the groove including a hexagonal bottom surface and six inclined surfaces arranged around the hexagonal bottom surface, the hexagonal bottom surface is fixed with a silicon microphone, and the six inclined surfaces are respectively fixed with a silicon microphone, the sampling surfaces of the six silicon microphones are at an angle of 30° to 60° with the hexagonal bottom surface, and the angles of the six sampling surfaces with the hexagonal bottom surface are equal; the sampling surface of the silicon microphone fixed to the hexagonal bottom surface faces the direction of the target sampling signal; The multi-channel acquisition system is connected to seven silicon microphones respectively to collect the sound signals generated during the underwater earthquake source simulation experiment collected by the seven silicon microphones, and transmits the sound signals to the data processing system. The underwater seismic source simulation system includes a water bucket, an underwater seismic source simulation device and an underwater seismic source monitoring device. The water bucket is used to simulate an underwater environment. The internal seven-directional silicon microphone device is fixed to the inner wall of the water bucket. The underwater seismic source simulation device includes a long-delay explosive and an explosive detonation system. The long-delay explosive is placed in the water bucket, and the explosive detonation system is placed outside the water bucket. The two are connected by a wire. The long-delay explosive is detonated by the explosive detonation system to simulate an underwater blast or vibration event. The underwater seismic source monitoring device includes a strain gauge, an accelerometer probe and a monitoring device. The strain gauge and the accelerometer probe are installed on the outer wall of the water bucket and are respectively connected to the monitoring device for signal connection. The monitoring device transmits the monitored strain signal and acceleration signal to the data processing system. The strain gauge and the accelerometer probe are at the same horizontal height as the internal seven-directional silicon microphone device, and the distance between the three is equal. The data processing system plots the collected sound signal into a voltage-time curve, the strain signal into a strain-time curve, and the acceleration signal into an acceleration-time curve, and uses a dynamic time bending algorithm to automatically align the voltage-time curve with the strain-time curve and the acceleration-time curve. It uses a peak detection algorithm to analyze the distribution and evolution laws of different events during the underwater earthquake source simulation experiment, uses an arrival time difference algorithm to calculate the coordinates of the earthquake source, and uses a beamforming algorithm to calculate the main wave transmission direction of the simulated earthquake source.

2. The underwater earthquake source monitoring device with silicon microphones arranged in seven directions according to claim 1 is characterized in that: The silicon microphone fixed to the bottom of the hexagon is located at the same level as the geometric center of the bucket.

3. The underwater earthquake source monitoring device with silicon microphones arranged in seven directions internally according to claim 1 is characterized in that: All seven silicon microphones are omnidirectional silicon microphones, collecting sound signals in the frequency range of 50~20000Hz and with a sensitivity of -22~-62dB.

4. The underwater earthquake source monitoring device with silicon microphones arranged in seven directions internally according to claim 1 is characterized in that: The multi-channel acquisition system is an eight-channel acquisition instrument, and the sampling frequency range is set to 20~100kHz.

5. The underwater earthquake source monitoring device with silicon microphones arranged in seven directions internally according to claim 1 is characterized in that: The long-delay explosive is placed at the geometric center of the water bucket.

6. A method for underwater earthquake source monitoring, characterized in that: Using the silicon microphone device with seven internal directions arranged as described in any one of claims 1 to 5, the underwater earthquake source monitoring method includes the following steps: S1. Install the silicon microphone device arranged in seven directions inside according to the design requirements; S2. Calibrate the sound source localization effect of the internal seven-directional silicon microphone device using a lead-breaking experiment; S3. Setting the detonation time of the explosive detonation system. After detonation, the voltage-time data collected by the multi-channel acquisition system and the strain-time data and acceleration-time data collected by the underwater seismic source monitoring equipment are input into the data processing system. S4. The data processing system uses a dynamic time bending algorithm to automatically align the voltage-time curve with the strain-time curve and the acceleration-time curve. The three types of aligned curves are then analyzed using a peak detection algorithm to analyze the distribution and evolution of different events during the underwater earthquake source simulation experiment. The arrival time difference algorithm is used to calculate the coordinates of the earthquake source, and the beamforming algorithm is used to determine the transmission direction of the main wave of the earthquake source.

7. The underwater earthquake source monitoring method according to claim 6, characterized in that: The method for calibrating the sound source localization effect of the internal seven-directional silicon microphone device using the lead-breaking experiment in step S2 includes: S2.

1. Extend a lead of a certain diameter to a certain length, with the lead forming a certain angle with the outer wall of the bucket. Break the lead at different locations on the outer wall of the bucket. Repeat the experiment multiple times at each break location. S2.

2. Use a multi-channel acquisition system to collect the sound signal generated by the lead breaking experiment and input the collected voltage-time data into the data processing system; S2.

3. The data processing system processes the collected voltage-time data to ensure that the error between the coordinates calculated from the sound source positioning of the lead break point and the actual lead break point coordinates does not exceed a certain threshold, and the calibration is considered to be successful.

8. The underwater earthquake source monitoring method according to claim 7, characterized in that: The coordinates of the lead-break position calculated by the sound source location are calculated by formula (1), which is as follows: （1） In formula (1), c is the speed of acoustic signal propagation underwater, is the time point when the i-th silicon microphone receives the lead-break sound signal, (x i ,y i , z i ) are the coordinates of the i-th silicon microphone, i=1~7, is the time point when the lead breaks and vibration occurs, ( , , ) is the coordinate of the lead break point; Compare the coordinates calculated by formula (1) with the actual lead-breaking point coordinates to ensure that the error between the calculated lead-breaking point coordinates and the actual lead-breaking point coordinates is less than 5%. If it is less than 5%, the calibration is considered to be passed and the subsequent steps can be carried out. If it is not satisfied, readjust the c value until the error is less than 5%.

9. The underwater earthquake source monitoring method according to claim 6, characterized in that: In step S4, the coordinates of the earthquake source are calculated using the arrival time difference algorithm, specifically according to formula (2): （2） In formula (2), c is the speed of the acoustic signal propagating underwater, which is determined by the sound source localization effect of the lead interruption experiment calibration in step S2; t i is the time point when the i-th silicon microphone receives the source sound signal, (x i ,y i , z i ) are the coordinates of the i-th silicon microphone, i=1~7, (x, y, z) are the coordinates of the source.

10. The underwater earthquake source monitoring method according to claim 9, characterized in that: When using the arrival time difference algorithm to calculate the coordinates of the earthquake source, the first silicon microphone located on the bottom surface is selected, and four silicon microphones are randomly selected from the six silicon microphones on the inclined surface. The coordinates of these five silicon microphones are substituted into formula (2) to determine the coordinate points (x, y, z) of the simulated earthquake source; the coordinates of the remaining two silicon microphones are substituted into formula (2) to verify the correctness of the calculated earthquake source coordinate points.

11. The underwater earthquake source monitoring method according to claim 6, characterized in that: In step S4, the beamforming algorithm is used to determine the main wave transmission direction of the earthquake source. Specifically, the main wave transmission direction of the earthquake source is determined by formula (3), which is as follows: （3） In formula (3), y(θ,φ) is the beamforming intensity of the acoustic signal in the (θ,φ) direction, θ is the horizontal angle of the earthquake source, ranging from (0,2π), and φ is the vertical angle of the earthquake source, ranging from (0,π). is the weight of the i-th silicon microphone in the (θ, φ) direction, , x i (t) is the time domain signal received by the i-th silicon microphone, i=2~7; Substituting the beamforming intensities and weights of the six silicon microphones on the six inclined planes into formula (3) can draw the beamforming intensity distribution diagram and obtain the main wave transmission distribution of the simulated earthquake source.

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