Device and method for monitoring underwater seismic source with silicon microphones arranged in seven directions

Abstract

The invention relates to an underwater seismic source monitoring device with silicon microphones arranged in seven directions inside. The underwater seismic source monitoring device 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 bracket and seven silicon microphones fixed on the internal seven-direction bracket; a groove is formed in the inner side wall of the internal seven-direction support, 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. According to the invention, the seven silicon microphones are arranged in a specific arrangement mode, so that the silicon microphones can be conveniently installed on underwater equipment to collect sound signals, the specific coordinate points of the simulated seismic source can be accurately calculated by using the collected sound signals, and the dominant wave transmission direction of the simulated seismic source can be calculated. A peak detection algorithm is adopted to analyze the distribution and evolution rules of different events in the underwater seismic source simulation experiment process.

Description

Technical Field

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

[0002] Acoustic signals are the signals with the longest underwater transmission distance and the most analytical value, so the monitoring and analysis of underwater acoustic signals is particularly important. Underwater acoustic signal monitoring technology can monitor and analyze the distribution and evolution laws of effective events generated during underwater vibration, 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. The linear array arrangement device has poor anti-interference ability, uneven angular resolution, poor resolution of depth information of the sound source, and does not consider the changes in the signal reception angle. 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 provide an underwater earthquake source monitoring device and method with silicon microphones arranged in seven directions internally in view of the deficiencies in the above-mentioned prior art. The silicon microphone has high integration, small size and light weight, and is convenient for installation 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 by 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] A device for monitoring underwater seismic sources with silicon microphones arranged in seven directions internally, comprising 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 comprises an internal seven-directional bracket and seven silicon microphones fixed on the internal seven-directional bracket; a groove is provided on the inner side wall of the internal seven-directional bracket, 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 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; the underwater seismic source simulation system comprises 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 bracket is provided with a groove ... are 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 sound signals generated during the underwater seismic source simulation experiment collected by the seven silicon microphones, and transmit The silicon microphone device is fixed to the inner wall of the bucket, the underwater seismic source simulation equipment is used to simulate underwater explosions or vibration events, the underwater seismic source monitoring equipment includes strain gauges, accelerometer probes and monitoring equipment, the strain gauges and accelerometer probes are installed on the outer wall of the bucket and are respectively connected to the monitoring equipment for signals, the monitoring equipment transmits the monitored strain signals and acceleration signals 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 hexagonal bottom surface faces the direction of the target sampling signal, and the sampling surfaces of the six silicon microphones fixed on the groove slope are at an angle of 30° to 60° with the hexagonal bottom surface, and the angles between the six sampling surfaces and the hexagonal bottom surface are equal.

[0007] In the above scheme, the silicon microphone fixed to the hexagonal bottom surface is 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 scheme, 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 scheme, the strain gauge and the accelerometer probe are at the same level as the internal seven-directional silicon microphone device, and the distances between the three are equal.

[0012] Correspondingly, the present invention also proposes an underwater seismic source monitoring method, which uses the above-mentioned silicon microphone device arranged in seven directions internally, and the underwater seismic 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, and inputting 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 into the data processing system after detonation;

[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 peak detection algorithm is used to analyze the distribution and evolution of different events in the underwater seismic source simulation experiment. The arrival time difference algorithm is used to calculate the coordinates of the seismic source, and the beam forming algorithm is used to determine the transmission direction of the main wave of the seismic source.

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

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

[0019] S2.2, using a multi-channel acquisition system to collect the sound signal generated by the lead breaking experiment, and inputting 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 coordinates calculated from the sound source positioning of the lead-breaking point and the coordinates of the actual lead-breaking point do not exceed a certain threshold, and the calibration is considered to be passed.

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

[0022]

[0023] In formula (1), c is the speed of acoustic signal propagation underwater, t i ' is the time point when the i-th silicon microphone receives the lead-off 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 lead break occurs vibration, (x', y', z') are the coordinates of the lead break 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, which is specifically calculated 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 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 ith silicon microphone, i=1~7, (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 beam forming 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). Formula (3) is as follows:

[0030]

[0031] In formula (3), For sound signal 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;

[0032] Substituting the beamforming strength 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. The present invention arranges seven silicon microphones in a specific arrangement in an internal seven-direction bracket, which is convenient for installation on underwater equipment to collect sound signals. The sound signals collected by the internal seven-direction silicon microphone device can be combined with the arrival time difference algorithm to more accurately calculate the specific coordinate points of the simulated earthquake source, use the beamforming algorithm to calculate the main wave transmission direction of the simulated earthquake source, use the dynamic time bending algorithm to automatically align the voltage-time curve with the strain-time curve and the acceleration-time curve, and use the peak detection algorithm to analyze the distribution and evolution of different events during the underwater earthquake source simulation experiment. Therefore, the present invention realizes the calculation of the location of the earthquake source, the calculation of the main wave transmission direction, the monitoring of the distribution of effective events and the evolution law of events during the underwater vibration process. Compared with the acoustic signal monitoring equipment arranged in a linear array, the internal seven-direction silicon microphone device of the present invention has the advantages of strong anti-interference ability, uniform angle resolution, and more accurate resolution of the depth information of the sound source; and the hexagonal silicon microphone array takes into account the changes in the signal receiving angle and can determine the main wave transmission direction.

[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. In addition, silicon microphones have low power consumption, are waterproof, and can work stably and continuously in underwater environments for a long 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 the overall structure diagram of the underwater earthquake source monitoring device with silicon microphones arranged in seven directions inside the present invention, and the figure shows an enlarged structure diagram of the internal seven-direction silicon microphone device;

[0038] Figure 2 It is a three-dimensional picture 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 4 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] Embodiment 1: Device embodiment

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

[0049] The internal seven-direction silicon microphone device 1 includes an internal seven-direction bracket 18 and seven silicon microphones fixed on the internal seven-direction bracket 18, which are respectively 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. A groove is provided on the inner side wall of the internal seven-direction bracket 18, and the groove includes a hexagonal bottom surface and six inclined surfaces arranged around the hexagonal bottom surface. The first silicon microphone 11 is fixed to the hexagonal bottom surface, and the second silicon microphone to the seventh silicon microphone are respectively fixed to the six inclined surfaces. The internal seven-direction silicon microphone device 1 can monitor the sound signal generated during the underwater seismic source simulation experiment, wherein the sampling surface of the first silicon microphone 11 is coplanar with the hexagonal bottom surface, and the sampling surface of the first silicon microphone 11 is arranged to face the target sampling signal direction.

[0050] The multi-channel acquisition system 2 is respectively connected to the seven silicon microphones for signal collection 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. The 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 accelerator probe 332 and a monitoring device 333. The strain gauge 331 and the accelerator probe 332 are attached and fixed to the outer wall of the water bucket 31 to monitor the strain and acceleration generated during the underwater seismic source simulation experiment, and are respectively connected to the monitoring device 333 for signal connection. The monitoring device 333 transmits the monitored strain signal and acceleration signal 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, 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 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 beam forming algorithm to calculate the main wave transmission direction of the simulated seismic source.

[0053] Further optimization, the angle between the inclined surface of the groove of the internal seven-direction bracket 18 and the bottom surface of the hexagon is 30° to 60°. Each silicon microphone is coplanar with its corresponding fixed surface and arranged in a regular hexagon. That is, the sampling surface of the second silicon microphone to the seventh silicon microphone forms an angle of 30° to 60° with the bottom surface of the hexagon, and the angles between the six sampling surfaces and the bottom surface of the hexagon are equal. This arrangement can improve the accuracy of source location and reduce the interference of environmental 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, capable of collecting 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] As a further optimization, all seven silicon microphones are fixed with hot melt adhesive.

[0057] Further optimization, the shape of the outer wall of the internal seven-direction bracket 18 is adapted to the shape of the inner wall of the bucket 31 to ensure that the internal seven-direction silicon microphone device 1 can be pasted and fixed to the inner wall of the bucket 31. The internal seven-direction bracket 18 is made by 3D printing. In this embodiment, the bucket 31 is a round barrel, and the outer wall of the internal seven-direction bracket 18 is an arc surface with a diameter equal to the diameter of the inner wall of the round 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 0.2 g to 1.0 g.

[0062] Further optimization is performed so that 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-direction bracket 18 by hot melt adhesive, the first to seventh silicon microphones are connected to the multi-channel acquisition system 2 and the power supply device by wires, the internal seven-direction silicon microphone device 1 is pasted and fixed on the inner wall of the bucket 31, and the first silicon microphone 11 is located at the same horizontal height of the geometric center of the bucket 31, the long-delay explosive 321 is connected to the explosive detonation system 322 by wires, the long-delay explosive 321 is fixed at the geometric center of the bucket 31 filled with water, the strain gauge 331 and the accelerator probe 332 are pasted and fixed on the outer wall of the bucket 31 and are located at the same horizontal height of the geometric center of the bucket 31, the strain gauge 331 and the accelerator probe 332 are connected to the monitoring device 333 by data lines, and the multi-channel acquisition system 2 and the monitoring device 333 are respectively connected to the data processing system 4, so as to form the silicon microphone underwater seismic source monitoring device with an internal seven-direction arrangement as described in the present invention.

[0065] Example 2: Method Example

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

[0067] S1. Install the silicon microphone device arranged in seven directions according to the above requirements. Fill the water bucket 31 with water to simulate the underwater environment, and place the water bucket 31 in a relatively isolated position without sharing the placement platform with other equipment. In this embodiment, the diameter of the barrel is 20 cm and the height is 50 cm. The eight-channel data acquisition instrument is set to a sampling frequency of 20 kHz, the power supply device is set to a 2V DC voltage regulator, 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 used 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, and the lead forms a certain angle with the outer wall of the bucket 31. Cut the lead at different locations on the outer wall of the bucket 31, and repeat the experiment multiple times at each lead-cutting location. In this embodiment, the lead is an HB lead with a diameter of 0.5 mm, the lead extends to a length of 2.5 mm, and the angle between the lead and the outer wall of the bucket 31 is 30°.

[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-breaking point calculated by the sound source positioning and the actual lead-breaking point coordinates do not exceed a certain threshold, that is, the calibration is considered to be passed. Specifically, the coordinates of the lead-breaking point calculated by the sound source positioning are calculated by formula (1), which is as follows:

[0072]

[0073] In formula (1), c is the speed of acoustic signal propagation underwater, t i ' is the time point when the i-th silicon microphone receives the lead-off sound signal, (x i ,y i , z i ) are the coordinates of the ith silicon microphone, i=1-7, t0' is the time point when the lead break occurs vibration, and (x', y', z') are the coordinates of the lead break 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%, the calibration is considered to be 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, setting the detonation time of the explosive detonation system 322, after detonation, the voltage-time data collected by the 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 the data processing system 4. In this embodiment, the explosive detonation system 322 is set to detonate the long-delay explosive 321 after 5 seconds, and the long-delay explosive 321 is detonated after ensuring safety.

[0076] S4, using the data processing system 4 to automatically align the voltage-time curve with the strain-time curve and the acceleration-time curve using the dynamic time bending algorithm, and using the peak detection algorithm to analyze the distribution and evolution of different events in the underwater earthquake source simulation experiment, using the arrival time difference algorithm to calculate the coordinates of the earthquake source, and judging the main wave transmission direction of the earthquake source. 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 into curves, and the three types of curves are automatically aligned using the dynamic time warping algorithm (the DTW function can be directly called in MATLAB to automatically align).

[0078] S4.2. Use the peak detection algorithm in MATLAB to analyze the distribution and evolution of different events in the underwater earthquake source simulation experiment by using the peak detection algorithm for the three types of aligned curves (directly calling the findpeaks function in MATLAB can automatically detect the peak value).

[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, the vertical axis is the collected voltage signal, the first time period is before the simulated seismic source is generated, the second time period is the process of simulating the seismic source generation, which lasts for 0.4 seconds, and the seismic source energy gradually decays. The signal fluctuations generated in the third time period are all acoustic signals generated by water surface fluctuations.

[0080] S4.3. Use the arrival time difference algorithm to calculate the coordinates of the simulated earthquake source, 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 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 ith silicon microphone, i=1~7, (x, y, z) are the coordinates of the simulated seismic 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 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 point 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 point.

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

[0085]

[0086] In formula (3), For sound signal 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 strength 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 modes, which are merely illustrative rather than 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 within the protection of the present invention.

Claims

1. An underwater seismic 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-direction silicon microphone device comprises an internal seven-direction bracket and seven silicon microphones fixed on the internal seven-direction bracket; a groove is provided on the inner side wall of the internal seven-direction bracket, 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 connected to the seven silicon microphones respectively to collect the sound signals generated during the underwater earthquake source simulation experiment collected by the seven silicon microphones, and transmit 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 is used to simulate underwater explosions or vibration events. 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 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 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.

2. The underwater seismic source monitoring device with silicon microphones arranged in seven directions internally according to claim 1 is characterized in that: The sampling surface of the silicon microphone fixed on the hexagonal bottom surface faces the target sampling signal direction, and the sampling surfaces of the six silicon microphones fixed on the groove slopes have an angle of 30° to 60° with the hexagonal bottom surface, and the angles between the six sampling surfaces and the hexagonal bottom surface are equal.

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

4. The underwater seismic 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. The frequency range of collecting sound signals is 50 to 20,000 Hz, and the sensitivity is -22 to -62 dB.

5. The underwater seismic 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.

6. The underwater seismic source monitoring device with silicon microphones arranged in seven directions internally according to claim 1 is characterized in that: 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. The explosive detonation system is used to detonate the long-delay explosive to simulate underwater blasting or vibration events.

7. The underwater seismic source monitoring device with silicon microphones arranged in seven directions internally according to claim 1 is characterized in that: The strain gauge, the accelerometer probe and the internal seven-directional silicon microphone device are at the same level, and the distances between the three are equal.

8. An underwater earthquake source monitoring method, characterized in that: Using the silicon microphone device arranged in seven directions internally as described in any one of claims 1 to 7, the underwater earthquake source monitoring method comprises 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, and inputting 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 into the data processing system after detonation; 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 peak detection algorithm is used to analyze the distribution and evolution of different events in the underwater seismic source simulation experiment. The arrival time difference algorithm is used to calculate the coordinates of the seismic source, and the beam forming algorithm is used to determine the transmission direction of the main wave of the seismic source.

9. The underwater earthquake source monitoring method according to claim 8, characterized in that: The method for calibrating the sound source localization effect of the internal seven-directional silicon microphone device by using the lead breaking experiment in step S2 includes: S2.

1. Extend a lead core of a certain diameter to a certain length, with the lead core and the outer wall of the bucket at a certain angle, and break the lead at different locations on the outer wall of the bucket. Repeat the experiment multiple times at each lead-breaking location. S2.2, using a multi-channel acquisition system to collect the sound signal generated by the lead breaking experiment, and inputting 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 coordinates calculated from the sound source positioning of the lead-breaking point and the coordinates of the actual lead-breaking point do not exceed a certain threshold, and the calibration is considered to be passed.

10. The underwater earthquake source monitoring method according to claim 9, characterized in that: The coordinates of the lead-break position calculated by the sound source positioning are calculated by formula (1), which is as follows: In formula (1), c is the speed of acoustic signal propagation underwater, t i ' is the time point when the i-th silicon microphone receives the lead-off 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 lead break occurs vibration, (x', y', z') are the coordinates of the lead break site; 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%.

11. The underwater earthquake source monitoring method according to claim 8, 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): 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 ith silicon microphone, i=1~7, (x, y, z) are the coordinates of the source.

12. The underwater earthquake source monitoring method according to claim 11, characterized in that: 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 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.

13. The underwater earthquake source monitoring method according to claim 8, characterized in that: In step S4, a beam forming 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). Formula (3) is as follows: In formula (3), For sound signal 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; Substituting the beamforming strength 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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