Acoustic detection technology principle prototype for ground characteristic identification

Abstract

The invention provides an acoustic detection principle prototype for ground characteristic identification. The acoustic detection principle prototype is composed of a sound wave probe section, a connecting section, an electronic circuit system section, a battery and a communication module section. A sonic probe is mounted in the sonic probe section; a gyroscope, a data acquisition module, a main controller and a memory are mounted in the electronic circuit system section; the data acquisition module comprises a sound wave probe signal processing circuit and an ADC acquisition chip; a communication isolation chip, a wireless communication module, a positioning module and a power supply module are installed in the battery and communication module section. The system is reasonable and compact in structural design, realizes system integration, volume miniaturization and light weight, can be applied to terramechanics remote and rapid exploration in disaster areas and areas where people are difficult to reach, breaks through the technical bottleneck of inaccurate measurement of traditional manual approaching exploration, space-based remote sensing and air-based geophysical prospecting, and is suitable for popularization and application. And in-situ accurate survey of terramechanics is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of geophysical exploration, and particularly to a prototype of an acoustic detection technology for ground characteristic identification. Background Art

[0002] At present, the methods for obtaining the physical property parameters of the elastic modulus, Poisson's ratio and density of ground soil are mainly divided into two aspects. One is static, such as standard geotechnical laboratory experiments such as triaxial compression tests, direct shear and compression tests; the other is based on the propagation characteristics of elastic waves in materials, such as seismic wave detection, acoustic logging and other technical means. Static laboratory experiments of soil physical property parameters require a large number of samples and complex experimental equipment, and are limited by soil sample collection. They belong to non-in-situ measurement technical means and are difficult to obtain in-situ physical property parameters.

[0003] The seismic wave detection method is an acoustic detection technical means widely used to obtain the elastic modulus and Poisson's ratio. Its basic process is to use elastic waves caused by natural or artificial excitation, and utilize the changes in the propagation characteristics of elastic waves in rock and soil with different elasticities and densities underground. By observing and analyzing the propagation law of elastic waves, a geophysical exploration method for inferring the properties and forms of underground rock and soil layers is carried out. Through the obtained time-domain and frequency-domain curves, based on the wave equation, the elastic modulus, Poisson's ratio and other ground physical properties of the formation are obtained. Due to the differences in the properties such as elasticity and density of different rock and soil layers, the propagation characteristics of elastic waves in them are different, and refraction and reflection also occur at the interfaces of rock and soil with different properties. The reflected wave signals are received by geophones installed on the ground or underground. By processing and analyzing the reflected wave signals, the structure and distribution of underground rock and soil layers can be inferred. Given the density, ultrasonic longitudinal wave velocity and ultrasonic transverse wave velocity of the medium, the physical property parameters such as Young's modulus, shear modulus and Poisson's ratio of the medium can be calculated.

[0004] However, this technical means requires a specific sound source to excite sound waves, and requires personnel to approach for survey. It is difficult to implement in disaster areas and areas where it is difficult for personnel to reach. At the same time, it mainly obtains physical property parameters such as the elastic modulus in depth, and cannot achieve the acquisition of the elastic modulus, Poisson's ratio and density in a remote and regional manner. Summary of the Invention

[0005] In view of the technical problems existing in the above background art, the present invention provides a prototype of an acoustic detection principle for ground characteristic identification, with a reasonable and compact structure design, realizing system integration, miniaturization of volume and light weight. It can be applied to the remote and rapid survey of ground mechanics in disaster areas and areas where it is difficult for personnel to reach, breaking through the technical bottlenecks of traditional manual approach survey and inaccurate space-based remote sensing and airborne geophysical exploration measurements, and realizing the in-situ accurate survey of ground mechanics.

[0006] To solve the above technical problems, an acoustic detection prototype for ground characteristic identification provided by the present invention is composed of a sound wave probe section, a connection section connected to the tail end of the sound wave probe section, an electronic circuit system section connected to the tail end of the connection section, and a battery and communication module section connected to the tail end of the electronic circuit system section;

[0007] A sound wave probe is installed in the sound wave probe section; the sound wave probe uses a three-component geophone and is placed in three directions of X, Y, and Z; an accelerometer for acceleration measurement is installed in the connection section; a gyroscope, a data acquisition module, a main controller, and a memory are installed in the electronic circuit system section; the data acquisition module includes a sound wave probe signal processing circuit and an ADC acquisition chip; a communication isolation chip, a wireless communication module, a positioning module, and a power supply module are installed in the battery and communication module section;

[0008] The signal output end of the sound wave probe is electrically connected to the signal input end of the sound wave probe signal processing circuit; the signal output ends of the sound wave probe signal processing circuit and the accelerometer are both electrically connected to the signal input end of the ADC acquisition chip; the signal output end of the ADC acquisition chip is connected to the signal input end of the communication isolation chip; the signal output end of the communication isolation chip is connected to the main controller; the gyroscope, the memory, the wireless communication module, the positioning module, and the power supply module are all electrically connected to the main controller.

[0009] For the acoustic detection prototype for ground characteristic identification, wherein: the sensitivity of the sound wave probe is 0.3V / cm / s ± 5%, and the detection frequency range is 0 - 100Hz.

[0010] For the acoustic detection prototype for ground characteristic identification, wherein: the gyroscope uses an IMU sensor and is used for attitude detection; the IMU sensor uses a digital 6-axis inertial navigation chip ICM20689, and the main controller acquires the 3-axis gyro data of the IMU sensor in the SPI manner and obtains the attitude angle value through data calculation.

[0011] The acoustic detection prototype for ground characteristic identification, wherein: the circuit of the IMU sensor consists of chip U13 and capacitors C55 to C58; the chip U13 is grounded through pin GND, connected to the power supply D3V3 through pins VDD and VDDIO, and grounded through pin FSYNC; one end of the capacitor C55 is connected to the pin FSYNC of the chip U13, and the other end is connected to the pin VDD of the chip U13; one end of the capacitor C56 is connected to the pin FSYNC of the chip U13, and the other end is connected to the pin VDD of the chip U13; one end of the capacitor C57 is grounded, and the other end is connected to the pin VDDIO of the chip U13; one end of the capacitor C58 is grounded, and the other end is connected to the pin REGOUT of the chip U13.

[0012] The acoustic detection prototype for ground characteristic identification, wherein: the data acquisition module is a sound wave signal acquisition board, which is installed inside the electronic circuit system section through a mounting bracket; the ADC acquisition chip selects a high-precision 16-bit chip ADS8688, and the first three channels, namely channels 0, 1, and 2, respectively acquire the voltage signal data of the three-component X, Y, and Z detectors of the sound wave probe in a differential manner.

[0013] The acoustic detection prototype for ground characteristic identification, wherein: the power supply module includes a lithium battery and a DC-DC module; the current output end of the lithium battery is electrically connected to the DC-DC module; the power output end of the DC-DC module is connected to the main controller; the lithium battery uses an 8.4V, 2S lithium battery to provide DC power for the main controller.

[0014] The acoustic detection prototype for ground characteristic identification, wherein: the positioning module is used for positioning and navigation and uses a GPS module of model NEO-M8N; the memory is used for Flash data storage and uses an SD card of model W25Q256JV for storage; the model of the accelerometer is ADXL1004BCPZ.

[0015] The acoustic detection prototype for ground characteristic identification, wherein: the main controller is an MCU chip of model STM32F40X;

[0016] The signal processing circuit of the sound wave probe consists of operational amplifiers Q1 to Q2, resistors R8 to R10, resistor R18, capacitor C36, and capacitor C38;

[0017] The non-inverting input terminal of the operational amplifier Q1 is connected to a 250mv power supply, the inverting input terminal of the operational amplifier Q1 is connected to the output terminal, and the output terminal of the operational amplifier Q1 is connected to an output terminal P3 of the sound wave probe is connected to N; the non-inverting input terminal of the operational amplifier Q2 is connected to the resistor R10 and through the resistor 10 to the other output terminal P3 of the acoustic probe is connected to P. The inverting input terminal of the operational amplifier Q2 is connected to the resistor R9 and grounded to AGND through the resistor R9. The output terminal of the operational amplifier Q2 is connected to the resistor R18 and through the resistor R18 to the pin CHANNEL of the A / D conversion input channel of the main controller on 1; one end of the capacitor C38 is grounded to AGND, and the other end is connected to the pin CHANNEL of the A / D conversion input channel of the main controller on 1; one end of the resistor R8 is connected to the inverting input terminal of the operational amplifier Q2, and the other end is connected to the output terminal of the operational amplifier Q2; the capacitor C36 is connected in parallel across the two ends of the resistor R8.

[0018] For the prototype of the acoustic detection principle for ground characteristics identification, where: the resistance value of the resistor R8 is 60K, the resistance values of the resistors R9 to R10 are 10K, the resistance value of the resistor R18 is 1K, and the capacitance value of the capacitor C36 is 15p / 50V.

[0019] Adopting the above technical solution, the present invention has the following beneficial effects:

[0020] Based on the previous impact penetration cone penetration test laboratory device, the present invention designs a ground mechanical parameter measurement device that couples impact dynamic cone penetration and acoustic detection technologies. It can collect acoustic signals generated by the impact of a free-falling dynamic cone penetrometer on the soil through an acoustic probe, and realize the inversion of the elastic modulus and Poisson's ratio of the soil from the acoustic signals; in addition, it has functions such as positioning, remote data communication, and attitude measurement.

[0021] The present invention breaks through the technical bottlenecks of traditional manual close-range survey, as well as inaccurate space-based remote sensing and airborne geophysical prospecting measurements, and realizes remote and in-situ precise survey of ground mechanics. The present invention realizes system integration, miniaturization of volume, and light weight in design. The present invention can be applied to remote and rapid surveys of ground mechanics in disaster areas and areas where it is difficult for people to reach. The present invention utilizes the design concept of inverting the elastic modulus and Poisson's ratio of ground physical and mechanical parameters from the acoustic signals generated by the impact of a free-falling dynamic cone penetrometer on the soil. Description of the Drawings

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 Schematic diagram of the overall structure of the acoustic detection prototype for ground characteristic identification of the present invention;

[0024] Figure 2 Right view of the acoustic detection prototype for ground characteristic identification of the present invention;

[0025] Figure 3 For the acoustic detection prototype of the ground characteristic identification of the present invention Figure 2 Cross-sectional view taken along line A-A;

[0026] Figure 4 Schematic diagram of the internal structure of the acoustic wave probe of the acoustic detection prototype for ground characteristic identification of the present invention;

[0027] Figure 5 Schematic diagram of the circuit connection principle of the acoustic detection prototype for ground characteristic identification of the present invention;

[0028] Figure 6 Circuit diagram of the IMU sensor involved in the acoustic detection prototype for ground characteristic identification of the present invention;

[0029] Figure 7 Interface diagram of the data acquisition software involved in the acoustic detection prototype for ground characteristic identification of the present invention;

[0030] Figure 8 Schematic diagram of the free-fall dynamic penetration test involved in the acoustic detection prototype for ground characteristic identification of the present invention;

[0031] Figure 9 Circuit diagram of the signal processing of the acoustic wave probe of the data acquisition module involved in the acoustic detection prototype for ground characteristic identification of the present invention. Specific implementation manners

[0032] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Next, the present invention will be further explained and described in conjunction with specific implementation manners.

[0034] As Figure 1-3 shown, an acoustic detection prototype for ground characteristic identification provided in this embodiment is successively composed of an acoustic wave probe section 1, a connection section 2, an electronic circuit system section 3, and a battery and communication module section 4 connected from beginning to end.

[0035] A sonic probe is installed inside the sonic probe section 1; the structure of the sonic probe is as follows Figure 4 shown, using a three-component geophone 11 and placed in three directions of X, Y, and Z (two horizontal and one vertical). The specific working principle is that when the sound wave reaches the detection point, the housing of the geophone 11 and the magnet steel vibrate accordingly, and the coil lags behind the magnet steel due to inertia, forming relative motion between the two. In such motion, the coil cuts the magnetic force line to generate an induced electromotive force, outputting a current signal corresponding to the vibration period. These signals can be amplified and recorded by a sonic acquisition instrument, thus realizing the electromechanical conversion of converting ground vibration signals into electrical vibrations and obtaining sound waves. The sensitivity of the sonic probe is 0.3V / cm / s ± 5%, and the detection frequency range is 0 - 100Hz.

[0036] An accelerometer, a gyroscope, a data acquisition module, a main controller, and a memory for acceleration measurement are installed inside the electronic circuit system section 3.

[0037] The model of the accelerometer is ADXL1004BCPZ.

[0038] The gyroscope uses an IMU sensor for attitude detection; among them, the IMU sensor uses a digital 6-axis inertial navigation chip ICM20689, and the main controller collects the 3-axis gyro data of the chip through the SPI method. By integrating the angular velocity measured by the gyroscope and combining the acceleration data, the attitude angle value is calculated using quaternions. As Figure 6 shown, the circuit of the IMU sensor consists of the chip U13, capacitors C55 - C58; the chip U13 is grounded through the pin GND, connected to the power supply D3V3 through the pins VDD and VDDIO, and grounded through the pin FSYNC; one end of the capacitor C55 is connected to the pin FSYNC of the chip U13, and the other end is connected to the pin VDD of the chip U13; one end of the capacitor C56 is connected to the pin FSYNC of the chip U13, and the other end is connected to the pin VDD of the chip U13; one end of the capacitor C57 is grounded, and the other end is connected to the pin VDDIO of the chip U13; one end of the capacitor C58 is grounded, and the other end is connected to the pin REGOUT of the chip U13.

[0039] The data acquisition module is a sonic signal acquisition board, which is installed inside the electronic circuit system section 3 through a mounting bracket 31 and includes a sonic probe signal processing circuit and an ADC acquisition chip. Among them, as Figure 9 shown, the sonic probe signal processing circuit consists of operational amplifiers Q1 - Q2, resistors R8 - R10, resistor R18, capacitors C36 and C38; among them, the non-inverting input terminal of the operational amplifier Q1 is connected to a 250mv power supply, the inverting input terminal of the operational amplifier Q1 is connected to the output terminal, and the output terminal of the operational amplifier Q1 is connected to an output terminal P3 of the sonic probe N is connected; the non-inverting input terminal of the operational amplifier Q2 is connected to the resistor R10 and is connected to the other output terminal P3_P of the acoustic wave probe through the resistor 10. The inverting input terminal of the operational amplifier Q2 is connected to the resistor R9 and is grounded to AGND through the resistor R9. The output terminal of the operational amplifier Q2 is connected to the resistor R18 and is connected to the pin CHANNEL of the A / D conversion input channel of the main controller through the resistor R18 On 1; one end of the capacitor C38 is grounded to AGND, and the other end is connected to the pin CHANNEL of the A / D conversion input channel of the main controller On 1; one end of the resistor R8 is connected to the inverting input terminal of the operational amplifier Q2, and the other end is connected to the output terminal of the operational amplifier Q2; the capacitor C36 is connected in parallel across both ends of the resistor R8. The resistance value of the resistor R8 is 60K, the resistance values of the resistors R9 to R10 are 10K, the resistance value of the resistor R18 is 1K, and the capacitance value of the capacitor C36 is 15p / 50V

[0040] The ADC acquisition chip selects the high-precision 16-bit chip ADS8688. The first three channels, namely channels 0, 1, and 2, respectively acquire the voltage signal data of the three components X, Y, and Z of the acoustic wave probe from the three detectors 11 in a differential manner. The actual test acquisition accuracy is higher than 1mV. Considering that the voltage input range of the three detectors 11 is between 0 - 2V, the resolution can reach about 2V / 1mV = 2000

[0041] The main controller is an MCU chip of the model STM32F40X and is used for data processing

[0042] The memory uses an SD card of the model W25Q256JV for storage and is used for Flash data storage

[0043] The battery and communication module section 4 is internally equipped with a wireless communication module 41, a power supply module 42, and a positioning module 43; on the outer end face of the battery and communication module section 4, there are an antenna interface 44, a power port 45, a charging port 46, a switch 47, and an antenna 48 installed at the antenna interface 44. Among them, the model of the wireless communication module 41 is CX3671-k, and its function is to transmit the collected data wirelessly to the remote ground end

[0044] The positioning module 43 uses a GPS module of the model NEO-M8N and is used for positioning and navigation

[0045] The power supply module 42 includes a lithium battery and a DC-DC module. The current output terminal of the lithium battery is electrically connected to the DC-DC module, and the power output terminal of the DC-DC module is connected to the main controller; the lithium battery uses a 2S (8.4V) lithium battery to provide DC power for the main controller

[0046] like Figure 5 As shown, the signal output end of the acoustic wave probe is electrically connected to the signal input end of the acoustic wave probe signal processing circuit; the signal output end of the acoustic wave probe signal processing circuit and the signal output end of the accelerometer are both electrically connected to the signal input end of the ADC acquisition chip; the signal output end of the ADC acquisition chip is connected to the signal input end of the communication isolation chip; the signal output end of the communication isolation chip is connected to the main controller; the gyroscope, the memory, the wireless communication module 41, the power supply module 42 and the positioning module 43 are all electrically connected to the main controller.

[0047] The acoustic detection principle prototype for ground feature identification of the present invention needs to meet the following performance indicators: ① It can realize the buried posture of the acoustic detector; ② System integration, miniaturization, and light weight; ③ It has positioning, self-organizing network and remote data communication functions; ④ It has impact resistance, waterproof and shockproof functions; ⑤ It meets the center of gravity design and aerodynamic shape design for vertical fall, etc.

[0048] The design of the acoustic wave probe complies with international standards and is used to install the integrated circuit and battery composed of the acoustic wave receiver, gyroscope module, etc. Inside the tail section is a power supply and wireless communication module, which is used for powering the integrated circuit and wirelessly transmitting data.

[0049] The sensor and data acquisition unit for acoustic wave acquisition were developed. The attitude angle measurement range of the prototype is 0-90°, with an accuracy better than 1°. The sampling frequency of the acoustic wave probe is not less than 6KHZ, and the total acquisition time is 200ms. In addition, the acoustic wave probe has a large impact force and deflection at the moment of entering the soil. The accelerometer needs to be directly subjected to this impact, and the attitude after entering the soil must also be acquired.

[0050] The supporting data acquisition software is installed on the ground receiving computer. Its main function is to collect and display the status information transmitted in real time by the acoustic detection principle prototype for ground feature identification. The software interface is as follows Figure 7 As shown in the figure, the program communicates with the device through the serial communication module, sends control commands to the device, receives and analyzes device data, and displays the data in the form of waveforms on the main interface of the application. The software interface can simultaneously display three waveform information of the X, Y, and Z axes, that is, the state of obtaining sound wave information.

[0051] Table 1 Component selection table

[0052]

[0053] Table 2 Performance parameter table of free-fall acoustic penetration instrument

[0054]

[0055] The structure of the present invention is reasonably and compactly designed, realizing system integration, miniaturization of volume and lightening of weight. It can be applied to the remote and rapid ground mechanics survey in disaster areas and areas difficult for personnel to reach, breaking through the technical bottlenecks of traditional manual close-range survey, inaccurate space-based remote sensing and air-based geophysical exploration measurement, and realizing in-situ precise survey of ground mechanics.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A prototype of acoustic detection principle for ground feature identification, characterized by: The acoustic detection principle prototype is composed of an acoustic wave probe section (1), a connecting section (2) connected to the tail end of the acoustic wave probe section (1), an electronic circuit system section (3) connected to the tail end of the connecting section (2), and a battery and communication module section (4) connected to the tail end of the electronic circuit system section (3); The acoustic wave probe section (1) is equipped with an acoustic wave probe; the acoustic wave probe adopts a three-component detector and is placed in three directions of X, Y and Z; the connecting section (2) is equipped with an accelerometer for acceleration measurement; the electronic circuit system section (3) is equipped with a gyroscope, a data acquisition module, a main controller and a memory; the data acquisition module includes an acoustic wave probe signal processing circuit and an ADC acquisition chip; the battery and communication module section (4) is equipped with a communication isolation chip, a wireless communication module, a positioning module and a power supply module; The signal output end of the acoustic wave probe is electrically connected to the signal input end of the acoustic wave probe signal processing circuit; the signal output end of the acoustic wave probe signal processing circuit and the signal output end of the accelerometer are both electrically connected to the signal input end of the ADC acquisition chip; the signal output end of the ADC acquisition chip is connected to the signal input end of the communication isolation chip; the signal output end of the communication isolation chip is connected to the main controller; the gyroscope, the memory, the wireless communication module, the positioning module and the power supply module are all electrically connected to the main controller.

2. The acoustic detection principle prototype for ground feature identification as claimed in claim 1, characterized in that: The sensitivity of the sonic probe is 0.3 V / cm / s±5%, and the detection frequency range is 0-100 Hz.

3. The acoustic detection principle prototype for ground feature identification as claimed in claim 1, characterized in that: The gyroscope adopts an IMU sensor and is used for attitude detection; the IMU sensor adopts a digital 6-axis inertial navigation chip ICM20689, and the main controller collects 3-axis gyroscope data of the IMU sensor through SPI, and obtains the attitude angle value through data solution.

4. The acoustic detection principle prototype for ground feature identification as claimed in claim 3, characterized in that: The circuit of the IMU sensor is composed of a chip U13 and capacitors C55 to C58; the chip U13 is grounded through pin GND, connected to the power supply D3V3 through pins VDD and VDDIO, and grounded through pin FSYNC; one end of the capacitor C55 is connected to pin FSYNC of the chip U13, and the other end is connected to pin VDD of the chip U13; one end of the capacitor C56 is connected to pin FSYNC of the chip U13, and the other end is connected to pin VDD of the chip U13; one end of the capacitor C57 is grounded, and the other end is connected to pin VDDIO of the chip U13; one end of the capacitor C58 is grounded, and the other end is connected to pin REGOUT of the chip U13.

5. The acoustic detection principle prototype for ground feature identification as claimed in claim 1, characterized in that: The data acquisition module is an acoustic wave signal acquisition board, which is installed inside the electronic circuit system section (3) through a mounting bracket; the ADC acquisition chip uses a high-precision 16-bit chip ADS8688, and the three channels 0, 1, and 2 respectively acquire the voltage signal data of the three components X, Y, and Z detectors of the acoustic wave probe in a differential manner.

6. The acoustic detection principle prototype for ground feature identification as claimed in claim 1, characterized in that: The power supply module includes a lithium battery and a DC-DC module; the current output end of the lithium battery is electrically connected to the DC-DC module; the power output end of the DC-DC module is connected to the main controller; the lithium battery adopts an 8.4V, 2S lithium battery to provide a DC power supply for the main controller.

7. The acoustic detection principle prototype for ground feature identification as claimed in claim 1, characterized in that: The positioning module is used for positioning and navigation and adopts a GPS module of model NEO-M8N; The memory is used for Flash data storage and adopts SD card storage with model W25Q256JV; The model of the accelerometer is ADXL1004BCPZ.

8. The acoustic detection principle prototype for ground feature identification as claimed in claim 1, characterized in that: The main controller is an MCU chip of model STM32F40X; The acoustic wave probe signal processing circuit is composed of operational amplifiers Q1-Q2, resistors R8-R10, resistor R18, capacitor C36 and capacitor C38; The in-phase input of the operational amplifier Q1 is connected to a 250mv power supply, the inverting input of the operational amplifier Q1 is connected to the output, and the output of the operational amplifier Q1 is connected to an output terminal P3_N of the acoustic wave probe; the in-phase input of the operational amplifier Q2 is connected to a resistor R10 and is connected to another output terminal P3_P of the acoustic wave probe through a resistor 10, the inverting input of the operational amplifier Q2 is connected to a resistor R9 and is grounded AGND through the resistor R9, the output of the operational amplifier Q2 is connected to a resistor R18 and is connected to a pin CHANNEL1 of an A / D conversion input channel of the main controller through the resistor R18; one end of the capacitor C38 is grounded AGND, and the other end is connected to a pin CHANNEL1 of an A / D conversion input channel of the main controller; one end of the resistor R8 is connected to the inverting input of the operational amplifier Q2, and the other end is connected to the output of the operational amplifier Q2; the capacitor C36 is connected in parallel to both ends of the resistor R8.

9. The acoustic detection principle prototype for ground feature identification as claimed in claim 8, characterized in that: The resistance value of the resistor R8 is 60K, the resistance value of the resistors R9 to R10 is 10K, the resistance value of the resistor R18 is 1K, and the capacitance value of the capacitor C36 is 15p / 50V.

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