In-situ calibration method for infrasound sensor

Abstract

The invention discloses an infrasound sensor in-situ calibration method, and belongs to the technical field of infrasound sensor in-situ calibration, an infrasound sensor in-situ calibration scheme is designed by adopting an acoustic signal calibration method, and a piston sounder comprises a piston sounding unit and a piston sounding control unit which are integrated into a whole. The piston sound production unit is connected with the to-be-calibrated infrasound sensor through a gas circuit, the gas circuit is provided with a solenoid valve used for controlling the on-off of the gas circuit, and the solenoid valve, the piston sound production unit and the to-be-calibrated infrasound sensor are all in signal connection with an infrasound monitoring system data collector. The infrasound monitoring system remotely controls the on-off of an electromagnetic valve and a piston sounder through an infrasound monitoring system data collector, and achieves the in-situ calibration of the sensitivity absolute value and the frequency response of an infrasound sensor through the collection and analysis of an infrasound sensor self-calibration electric signal. The problems that the application range of an existing infrasound sensor calibration method is limited, and absolute calibration of the sensitivity of the sensor cannot be achieved are effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of in-situ calibration of infrasound sensors, and particularly relates to an in-situ calibration method for an infrasound sensor. Background Art

[0002] Infrasound usually refers to sound waves with a frequency below 20Hz, which are commonly found in nature, industrial production, transportation and military activities, such as natural phenomena such as earthquakes and volcanic eruptions, operation of large machinery, transportation, rocket and missile launches, industrial explosions and nuclear explosions, and supersonic aircraft flights.

[0003] The signal characteristics of infrasound waves are related to their generation mechanism. Different target sound sources have different sound generation mechanisms, and the kinematic and dynamic characteristics of the infrasound signals generated by the same target sound source can also vary significantly. Therefore, by deploying infrasound sensor arrays to collect and analyze infrasound wave signals and perform feature extraction, it is possible to locate the infrasound source and comprehensively identify its fine parameters. Due to the strong penetration ability and long propagation distance of infrasound waves, monitoring technology using infrasound sensor arrays for infrasound source location and identification is widely used in fields such as national defense security, geological disaster prevention and control, and geophysics research, with significant technical advantages.

[0004] Infrasound monitoring systems are typically deployed in the field, often unattended for extended periods. To ensure real-time verification of their operational status, ensure the validity and reliability of monitoring data, and avoid missed or false alarms of major incidents, an online monitoring system is urgently needed. The primary challenge is the in-situ calibration of their core components, the infrasound sensor. The sensitivity and frequency response of an infrasound sensor are fundamental parameters describing its metrological performance and are key parameters for in-situ calibration.

[0005] Currently, there is an electrical signal simulation method for calibrating infrasound sensors. The electrical signal simulation method generates a simulated physical field through electrical signal excitation. There are two typical methods, which are mainly used in electromagnetic bellows cavity infrasound sensors and capacitive infrasound sensors.

[0006] The basic structure and operating principle of an electromagnetic bellows-type infrasound sensor are as follows: a closed coil is connected to a vacuum membrane consisting of a pressure-sensitive membrane and a bellows. The pressure-sensitive membrane deforms in response to changes in air pressure, driving the coil to cut through magnetic flux lines, generating an induced current. After subsequent circuit processing, the output voltage reflects information such as the frequency and amplitude of the infrasound wave being measured. The self-calibration principle of this infrasound sensor is as follows: an alternating current flows through the built-in calibration coil, generating an alternating magnetic field. This interacts with a fixed magnet, causing the vacuum membrane connected to the calibration coil to displace, causing the pressure-sensitive membrane to deform, simulating the effect of infrasound pressure fluctuations. The response voltage generated by the closed coil enables self-calibration of the infrasound sensor.

[0007] The basic structure and operating principle of a capacitive infrasound sensor are as follows: a capacitor is formed between the microphone diaphragm and the back plate. An external polarization voltage is applied, or the electret material carries a fixed charge on the back plate. When sound waves act on the microphone diaphragm, the diaphragm vibrates in response to changes in sound pressure, causing the distance between the diaphragm and the back plate to vary periodically. This causes the voltage across the capacitor to change in response to the applied sound pressure. The electrical signal simulation method for self-calibration of this type of infrasound sensor is also known as the electrostatic excitation method. The electrostatic actuator primarily consists of a conductive, rigid plate. During electrostatic excitation self-calibration, the electrostatic actuator is typically placed above the microphone diaphragm. A superimposed voltage of a DC voltage and a sinusoidal AC voltage is applied to the actuator, effectively creating an electrostatic field between the actuator and the microphone diaphragm. This electrostatic field simulates the effects of sound pressure. To ensure static pressure balance on both sides of the microphone diaphragm, the electrostatic actuator is provided with slots or small holes.

[0008] Both of these electrical signal simulation methods are relatively mature, but their applicability is limited. The electromagnetic coil excitation method is only applicable to electromagnetic bellows-type infrasound sensors, while the electrostatic excitation method is only applicable to capacitive infrasound sensors. It is not applicable to infrasound sensors based on other principles, such as optical fiber and MEMS. Furthermore, the electrostatic excitation method requires a high-voltage DC power supply (e.g., 800V) during calibration, which poses safety risks. For example, sparks caused by excessive humidity and dust can easily penetrate the diaphragm of a capacitive microphone, damaging the sensor. Furthermore, these methods can only calibrate the relative frequency response of an infrasound sensor's sensitivity; they cannot calibrate its absolute value. Summary of the Invention

[0009] The object of the present invention is to provide an in-situ calibration method for an infrasound sensor, so as to solve the problem that the existing calibration methods for infrasound sensors have a limited scope of application and cannot achieve absolute calibration of the sensor sensitivity.

[0010] The technical solution adopted in the present invention is as follows:

[0011] An in-situ calibration method for an infrasound sensor comprises the following steps:

[0012] (1) Constructing an in-situ calibration system for an infrasound sensor, wherein the in-situ calibration system for the infrasound sensor includes a piston sounder, wherein the piston sounder includes a piston sounding unit and a piston sounding control unit, wherein the piston sounding unit is connected to the infrasound sensor to be calibrated via an air circuit, wherein the air circuit is provided with an electromagnetic valve for controlling the on-off of the air circuit, wherein the electromagnetic valve, the piston sounder, and the infrasound sensor to be calibrated are all signal-connected to an infrasound monitoring system data collector, wherein the infrasound monitoring system data collector is signal-connected to an infrasound monitoring system remote communication module, and wherein the infrasound monitoring system remote communication module is signal-connected to the infrasound monitoring system;

[0013] (2) The infrasound monitoring system sends a self-calibration instruction to the infrasound monitoring system data collector through the infrasound monitoring system remote communication module; the infrasound monitoring system data collector sends a signal to control the solenoid valve to open, and the infrasound sensor to be calibrated is connected to the air path interface of the piston sounder, and the infrasound sensor is switched from the normal working state to the self-calibration state; at the same time, the infrasound monitoring system data collector triggers the piston sound control unit to work, and inputs the set values of the calibration frequency and the calibration sound pressure level into the piston sound control unit;

[0014] (3) The piston sound control unit drives the piston sound unit to generate a standard infrasound wave with a frequency and a sound pressure level that meet the set values, and inputs the standard infrasound wave to the infrasound sensor to be calibrated;

[0015] (4) The electrical signal output of the infrasound sensor to be calibrated in response to the standard infrasound wave is collected by the infrasound monitoring system data collector, and the response voltage of the infrasound sensor is analyzed and calculated. Based on the set value of the pistonphone calibration sound pressure level, the self-calibration result of the infrasound sensor sensitivity is obtained;

[0016] (5) After the infrasound sensor self-calibration is completed, the infrasound monitoring system data collector controls the solenoid valve to cut off the air connection between the infrasound sensor and the piston sounder, stops triggering the piston sound control unit, and the infrasound sensor is connected to the atmosphere and enters the normal monitoring state.

[0017] Furthermore, the piston sound unit is a dynamic speaker excitation type piston sound structure with a built-in reference microphone unit, and the piston sound control unit includes a 200V polarized power supply module for powering the reference microphone unit, an air pressure and temperature measurement module, a DDS signal generator, an MCU controller, and a communication interface.

[0018] Furthermore, the process of the piston sound control unit driving the piston sound unit to generate standard infrasound waves with a frequency and sound pressure level that meet the set values is as follows: the MCU controller receives the set value signals of the calibration frequency and the calibration sound pressure level and configures the frequency and amplitude of the DDS signal generator. The DDS signal generator outputs an electrical signal to drive the piston sound unit to work. The response voltage of the reference microphone unit is converted into a digital signal by A / D. The sound pressure level radiated by the piston sound unit at this time is calculated according to the sensitivity of the reference microphone unit. The sensitivity of the reference microphone unit is corrected in combination with the air pressure and temperature measurement results obtained by the air pressure and temperature measurement module. The calibrated sound pressure thus obtained is compared with the set value, and the amplitude of the electrical signal output by the DDS signal generator is feedback-controlled until the calibrated sound pressure is consistent with the set value.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0020] 1. In the present invention, an acoustic signal calibration method is used to design an in-situ calibration scheme for the infrasound sensor, which can realize the in-situ calibration of the absolute value of the infrasound sensor sensitivity and its frequency response. This effectively solves the problem that electrical signal calibration methods such as the electrostatic excitation method and the electromagnetic coil excitation method have limited applicability and cannot achieve absolute calibration of the sensor sensitivity.

[0021] 2. In the present invention, the sound calibrator adopts a piston sounder structure in which the sound generation and control unit are integrated into one. Through the built-in reference microphone unit and sound pressure feedback control, the stability and environmental adaptability of the sound calibrator's output sound pressure level are improved. The operating frequency range of the piston sounder covers 0.01Hz to 20Hz, which can be further expanded by optimizing the excitation and sealing methods of the piston sounding unit.

[0022] 3. In the present invention, the infrasound monitoring system, through the infrasound monitoring system remote communication module and the infrasound monitoring system data collector, can remotely control the in-situ calibration of the infrasound sensor. When a self-calibration command is issued, the solenoid valve opens, the pistonphone is triggered and activated, and the air path between the infrasound sensor and the pistonphone is connected. The infrasound sensor's response voltage is collected and analyzed by the infrasound monitoring system data collector to obtain the self-calibration result of its sound pressure sensitivity. When the self-calibration is completed command is issued, the solenoid valve and pistonphone are closed, the infrasound sensor is connected to the atmosphere, and the infrasound sensor enters the normal monitoring state. This can be used for online monitoring of the operating status of unmanned infrasound monitoring systems in the field for long-term, unattended operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort, among which:

[0024] Figure 1 It is a schematic diagram of the principle of the present invention;

[0025] Figure 2 Schematic diagram of the composition of the piston sounder of the present invention. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0028] It should be noted that reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition or explanation in subsequent drawings.

[0029] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" and the like indicate positions or locations based on the positions shown in the accompanying drawings, or the positions or locations in which the inventive product is typically placed when in use. These terms are intended merely to simplify the description of the present invention and do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] Furthermore, terms such as "horizontal" and "vertical" do not necessarily mean that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0031] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific contexts.

[0032] In conjunction with the instructions Figure 1 ,

[0033] An in-situ calibration method for an infrasound sensor comprises the following steps:

[0034] (1) Constructing an in-situ calibration system for an infrasound sensor, wherein the in-situ calibration system for the infrasound sensor includes a piston sounder, wherein the piston sounder includes a piston sounding unit and a piston sounding control unit, wherein the piston sounding unit is connected to the infrasound sensor to be calibrated via an air circuit, wherein the air circuit is provided with an electromagnetic valve for controlling the on-off of the air circuit, wherein the electromagnetic valve, the piston sounder, and the infrasound sensor to be calibrated are all signal-connected to an infrasound monitoring system data collector, wherein the infrasound monitoring system data collector is signal-connected to an infrasound monitoring system remote communication module, and wherein the infrasound monitoring system remote communication module is signal-connected to the infrasound monitoring system;

[0035] (2) The infrasound monitoring system sends a self-calibration instruction to the infrasound monitoring system data collector through the infrasound monitoring system remote communication module; the infrasound monitoring system data collector sends a signal to control the solenoid valve to open, and the infrasound sensor to be calibrated is connected to the air path interface of the piston sounder, and the infrasound sensor is switched from the normal working state to the self-calibration state; at the same time, the infrasound monitoring system data collector triggers the piston sound control unit to work, and inputs the set values of the calibration frequency and the calibration sound pressure level into the piston sound control unit;

[0036] (3) The piston sound control unit drives the piston sound unit to generate a standard infrasound wave with a frequency and a sound pressure level that meet the set values, and inputs the standard infrasound wave to the infrasound sensor to be calibrated;

[0037] (4) The electrical signal output of the infrasound sensor to be calibrated in response to the standard infrasound wave is collected by the infrasound monitoring system data collector, and the response voltage of the infrasound sensor is analyzed and calculated. Based on the set value of the pistonphone calibration sound pressure level, the self-calibration result of the infrasound sensor sensitivity is obtained:

[0038]

[0039] In formula (1), l is the sound pressure sensitivity of the infrasound sensor, U and p are the response voltage and calibration sound pressure of the infrasound sensor during the self-calibration process;

[0040] (5) After the infrasound sensor self-calibration is completed, the data acquisition system controls the solenoid valve to cut off the air connection between the infrasound sensor and the piston sounder, stops triggering the piston sound control unit, and the infrasound sensor is connected to the atmosphere and enters the normal monitoring state.

[0041] Specifically, the piston sound unit is a dynamic speaker-excited piston sound structure with a built-in reference microphone unit. The piston sound control unit includes a 200V polarized power supply module for powering the reference microphone unit, an air pressure and temperature measurement module, a DDS signal generator, an MCU controller, and a communication interface.

[0042] During the implementation of this embodiment, the piston sounder is an integrated piston sounding unit and a piston sounding control unit. The piston sounding unit is connected to the infrasound sensor to be calibrated through an air circuit. An electromagnetic valve for controlling the on / off of the air circuit is provided on the air circuit. The electromagnetic valve, the piston sounder, and the infrasound sensor to be calibrated are all signal-connected to an infrasound monitoring system data collector. The infrasound monitoring system data collector is signal-connected to an infrasound monitoring system remote communication module. The infrasound monitoring system remote communication module is signal-connected to the infrasound monitoring system. The infrasound monitoring system remote communication module is signal-connected to the infrasound monitoring system through the infrasound monitoring system data collector. The infrasound monitoring system remotely controls the on / off of the electromagnetic valve and the piston sounder, and collects and analyzes the self-calibration electrical signal of the infrasound sensor, thereby realizing in-situ calibration of the infrasound sensor.

[0043] Among them, the piston sound unit is a dynamic speaker-excited piston sound structure with a built-in reference microphone unit. It generates standard infrasound waves with controllable frequency and amplitude under the drive of the piston sound control unit; the piston sound control unit is composed of a 200V polarization power supply module of the reference microphone unit, an air pressure and temperature measurement module, a DDS signal generator, an MCU controller and a communication interface with the infrasound monitoring system data collector. In actual work, the infrasound monitoring system data collector issues a start-up command to set the calibration frequency and calibration sound pressure level. The MCU controller receives the set value signals of the calibration frequency and calibration sound pressure level and The frequency and amplitude of the DDS signal generator are configured. The DDS signal generator outputs an electrical signal to drive the piston sound unit. The response voltage of the reference microphone unit is converted into a digital signal through analog-to-digital conversion. The sound pressure level radiated by the piston sound unit at this time is calculated based on the sensitivity of the reference microphone unit. The sensitivity of the reference microphone unit is corrected in combination with the air pressure and temperature measurement results obtained by the air pressure and temperature measurement module. The resulting calibration sound pressure is compared with the set value, and the amplitude of the electrical signal output by the DDS signal generator is feedback-controlled until the calibration sound pressure is consistent with the set value, thereby improving the stability of the calibration sound pressure level of the piston sounder.

[0044] The in-situ calibration scheme of the infrasound sensor is designed by using the acoustic signal calibration method, which can realize the in-situ calibration of the absolute value of the infrasound sensor sensitivity and its frequency response. It effectively solves the problem that electrical signal calibration methods such as the electrostatic excitation method and the electromagnetic coil excitation method have limited applicability and cannot achieve absolute calibration of the sensor sensitivity.

[0045] The piston sounder integrates the sound unit and control unit into one, and improves the stability and environmental adaptability of the sound calibrator's output sound pressure level through the built-in reference microphone unit and sound pressure feedback control. The operating frequency range of the piston sounder covers 0.01Hz to 20Hz, which can be further expanded by optimizing the excitation and sealing methods of the piston sound unit.

[0046] The infrasound monitoring system, through its remote communication module and data collector, enables remote control of in-situ calibration of the infrasound sensor. When a self-calibration command is issued, the solenoid valve opens, the pistonphone is triggered, and the air path between the infrasound sensor and the pistonphone is connected. The infrasound sensor's response voltage is collected and analyzed by the data collector to obtain the self-calibration result of its sound pressure sensitivity. When the self-calibration is complete, the solenoid valve and pistonphone close, the infrasound sensor connects to the atmosphere, and the system enters normal monitoring mode. This allows for online monitoring of the operating status of unmanned, long-term field operations.

[0047] Among them, the piston sound unit can choose a variety of excitation methods such as dynamic speakers, linear modules, voice coil motors, etc., and the reference microphone unit can choose the B&K 4193-L-004 working standard microphone unit, etc.

[0048] The above are the embodiments of the present invention. The foregoing are the preferred embodiments of the present invention. If the preferred implementation methods in each preferred embodiment are not obviously self-contradictory or based on a certain preferred implementation method, each preferred implementation method can be arbitrarily superimposed and used in combination. The embodiments and the specific parameters in the embodiments are only for the purpose of clearly describing the verification process of the invention, and are not intended to limit the scope of patent protection of the present invention. The scope of patent protection of the present invention is still subject to its claims. Any equivalent structural changes made by using the contents of the description and drawings of the present invention should also be included in the scope of protection of the present invention.

Claims

1. An in-situ calibration method for an infrasound sensor, characterized in that: The following steps are involved: (1) Constructing an in-situ calibration system for an infrasound sensor, wherein the in-situ calibration system for the infrasound sensor includes a piston sounder, wherein the piston sounder includes a piston sounding unit and a piston sounding control unit, wherein the piston sounding unit is connected to the infrasound sensor to be calibrated via an air circuit, wherein the air circuit is provided with an electromagnetic valve for controlling the on-off of the air circuit, wherein the electromagnetic valve, the piston sounder, and the infrasound sensor to be calibrated are all signal-connected to an infrasound monitoring system data collector, wherein the infrasound monitoring system data collector is signal-connected to an infrasound monitoring system remote communication module, and wherein the infrasound monitoring system remote communication module is signal-connected to the infrasound monitoring system; (2) The infrasound monitoring system sends a self-calibration instruction to the infrasound monitoring system data collector through the infrasound monitoring system remote communication module; the infrasound monitoring system data collector sends a signal to control the solenoid valve to open, and the infrasound sensor to be calibrated is connected to the air path interface of the piston sounder, and the infrasound sensor is switched from the normal working state to the self-calibration state; at the same time, the infrasound monitoring system data collector triggers the piston sound control unit to work, and inputs the set values of the calibration frequency and the calibration sound pressure level into the piston sound control unit; (3) The piston sound control unit drives the piston sound unit to generate a standard infrasound wave with a frequency and a sound pressure level that meet the set values, and inputs the standard infrasound wave to the infrasound sensor to be calibrated; (4) The electrical signal output of the infrasound sensor to be calibrated in response to the standard infrasound wave is collected by the infrasound monitoring system data collector, and the response voltage of the infrasound sensor is analyzed and calculated. Based on the set value of the pistonphone calibration sound pressure level, the self-calibration result of the infrasound sensor sensitivity is obtained; (5) After the infrasound sensor self-calibration is completed, the infrasound monitoring system data collector controls the solenoid valve to cut off the air connection between the infrasound sensor and the piston sounder, stops triggering the piston sound control unit, and the infrasound sensor is connected to the atmosphere and enters the normal monitoring state.

2. The in-situ calibration method of an infrasound sensor according to claim 1, characterized in that: The piston sound unit is a dynamic speaker-excited piston sound structure with a built-in reference microphone unit. The piston sound control unit includes a 200V polarized power supply module for powering the reference microphone unit, an air pressure and temperature measurement module, a DDS signal generator, an MCU controller, and a communication interface.

3. The in-situ calibration method of an infrasound sensor according to claim 2, characterized in that: In the step (3), the process of the piston sound control unit driving the piston sound unit to generate a standard infrasound wave with a frequency and sound pressure level that meets the set value is as follows: the MCU controller receives the set value signal of the calibration frequency and the calibration sound pressure level and configures the frequency and amplitude of the DDS signal generator, the DDS signal generator outputs an electrical signal to drive the piston sound unit to work, the response voltage of the reference microphone unit is converted by A / D analog-to-digital conversion, and the sound pressure level radiated by the piston sound unit at this time is calculated according to the sensitivity of the reference microphone unit. The sensitivity of the reference microphone unit is corrected in combination with the air pressure and temperature measurement results obtained by the air pressure and temperature measurement module, the calibration sound pressure thus obtained is compared with the set value, and the amplitude of the electrical signal output by the DDS signal generator is feedback-controlled until the calibration sound pressure is consistent with the set value.

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