Infrasound event positioning method and system
By adopting gridding and back-projection technology for single sensor deployment in infrasound monitoring, the limitations of traditional methods in complex terrain and remote areas are overcome, and high-precision infrasound event positioning is achieved, which is suitable for stations with single sensor deployment.
Patent Information
- Application Number
- CN202510915094.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-03
- Publication Date
- 2025-09-30
AI Technical Summary
Existing infrasound monitoring technology has limited application in complex terrain and remote areas, and a single sensor deployment cannot provide effective positioning results. Traditional methods rely on array deployment and have a high sensor failure rate, resulting in inaccurate positioning.
An infrasound event location method with a single sensor deployment is adopted. The study area is discretized into regular spatial grid units, back-projection and envelope energy extraction are performed based on the infrasound velocity and grid nodes, the infrasound waveform envelope is stacked to determine the infrasound source position, and the Hilbert transform and back-projection techniques are used for precise positioning.
It achieves accurate positioning of infrasound events with a single sensor deployment, has high resolution and robustness, is suitable for complex terrain and remote areas, and reduces the requirements for array deployment.
Smart Images
Figure CN120722283A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of infrasound monitoring, and in particular to a method and system for locating infrasound events. Background Art
[0002] In infrasound monitoring, when a suspicious signal is received, the parameters of the infrasound source need to be estimated, including the location of the infrasound source, the time of occurrence, etc. The accurate estimation of these parameters is crucial for the identification and subsequent analysis of the event. At present, the azimuth and geographical coordinates measured by two or more arrays are widely used to locate the latitude and longitude of the infrasound source by mapping them to the earth coordinate system. These methods usually require the infrasound station to be deployed as an array, that is, multiple infrasound sensors constitute an array. Traditional array positioning methods mainly rely on an array composed of multiple sensors to locate the sound source by measuring the azimuth. For example, the Progressive Multi-Channel Correlation (PMCC) method requires at least 4 sensors (spacing > 500m) to ensure an azimuth estimation accuracy of ±5°. The basic principle of these methods is to use the time difference between the signals received by multiple sensors to determine the location of the sound source through triangulation or beamforming technology. However, these methods have some limitations in practical applications: (1) The array deployment has high requirements for the location and spacing of sensors, which limits its application in complex terrain and remote areas. (2) Traditional methods cannot provide effective positioning results when a single sensor is deployed. (3) Traditional methods use the time difference between the signals received by multiple sensors for positioning. Therefore, this type of method requires the detection of the infrasound arrival time before positioning. According to the CTBTO 2022 annual report, 23% of the 60 infrasound monitoring stations in the world have been in a long-term degraded state due to sensor failure. Traditional array-based positioning methods cannot use a single sensor for array deployment. Therefore, there is an urgent need to develop a positioning technology that can be applied to stations deployed with a single sensor. Summary of the Invention
[0003] The purpose of this application is to provide an infrasound event locating method and system, which can ensure the accuracy of infrasound event locating when only a single sensor is deployed at a station.
[0004] To achieve the above objectives, this application provides the following solutions:
[0005] In a first aspect, the present application provides an infrasound event location method applicable to a station with a single sensor deployment; the infrasound event location method comprises:
[0006] According to the set grid spacing, the study area is discretized into regular spatial grid cells;
[0007] determining a grid node based on the spatial network unit;
[0008] reading an infrasound waveform from a sensor at the station and preprocessing the infrasound waveform;
[0009] Based on the infrasound velocity and the distance between each grid node and the station, the pre-processed infrasound waveform is back-projected to obtain a back-projected infrasound waveform;
[0010] The Hilbert transform is applied to the back-projected infrasound waveform to extract the envelope energy and obtain the infrasound waveform envelope corresponding to the infrasound station when each grid node is regarded as a potential infrasound source.
[0011] The infrasound waveform envelopes are stacked to obtain the stacking value of each grid node, and the grid node corresponding to the maximum stacking value is used as the preliminary location of the infrasound source;
[0012] Taking the initially located infrasound source as the center, a set shape with a length of n times the set grid spacing is used as the new study area, and the step of discretizing the study area into regular spatial grid cells is returned to obtain the infrasound source position;
[0013] within a set infrasound velocity range, selecting a new infrasound velocity according to a set gradient, and returning to the step of back-projecting the pre-processed infrasound waveform based on the infrasound velocity and the distance between each grid node and the station position to obtain a back-projected infrasound waveform, thereby obtaining a plurality of new infrasound source positions;
[0014] The infrasound source position and the stacked values of multiple new infrasound source positions are compared, and the infrasound source position corresponding to the maximum stacked value is used as the final infrasound source position to achieve the positioning of the infrasound event.
[0015] Optionally, the preprocessing method includes: linear detrending processing, Tukey window tapering processing and downsampling processing.
[0016] Optionally, based on the infrasound velocity and the distance between each grid node and the station, back-projecting the pre-processed infrasound waveform to obtain a back-projected infrasound waveform includes:
[0017] Determine the propagation time based on the infrasound velocity and the distance between each grid node and the station;
[0018] The propagation time is used as an offset to perform offset processing on the pre-processed infrasound waveform to obtain a back-projected infrasound waveform.
[0019] Optionally, stacking the infrasound waveform envelopes to obtain a stacking value for each grid node includes:
[0020] Using stacking function The infrasound waveform envelope is stacked to obtain the stacking value of each grid node; where N is the number of sensors, u i (t) is the i-th infrasound waveform envelope, x is the position of the grid node, A(x,t) is the stacking function, and t is the time variable corresponding to the infrasound waveform envelope.
[0021] Optionally, the set shape is a square.
[0022] Optionally, the set infrasonic speed range is [320m / s, 360m / s].
[0023] Optionally, the set grid spacing is set according to a maximum distance of infrasound wave propagation.
[0024] In a second aspect, the present application provides an infrasound event locating system, comprising: a processor and a memory; the processor is connected to the memory; a computer program is stored in the memory; the processor executes the computer program to implement the steps of the infrasound event locating method provided above.
[0025] Optionally, the memory is a computer-readable storage medium.
[0026] According to the specific embodiments provided in this application, this application has the following technical effects:
[0027] This application provides a method and system for locating infrasound events. This method, which does not require an array-based infrasound station, only requires the ability to obtain infrasound waveforms from sensors within the station. Infrasound events can be located based on these waveforms. Therefore, this application is applicable to stations with a single sensor. Furthermore, by updating the study area and infrasound velocity, multiple infrasound source locations are determined, and the location corresponding to the maximum stacked value is selected as the final location, ensuring the accuracy of infrasound event location. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0029] Figure 1 A schematic flow chart of a method for locating an infrasound event provided in one embodiment of the present application;
[0030] Figure 2 A schematic diagram of grid division provided in an embodiment of the present application;
[0031] Figure 3A schematic diagram of a station receiving waveform provided in one embodiment of the present application;
[0032] Figure 4 A schematic diagram of a waveform after reverse projection provided in an embodiment of the present application;
[0033] Figure 5 A schematic diagram of an envelope stack provided in an embodiment of the present application;
[0034] Figure 6 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION
[0035] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.
[0036] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.
[0037] In an exemplary embodiment, the present application provides an infrasound event location method applicable to a single sensor deployment station. The method is executed by a computer device, specifically a computer device such as a terminal or a server, or a terminal and a server. In the embodiment of the present application, the method is described by taking the application of the method to the server as an example. Figure 1 As shown, the method includes:
[0038] Step 100: discretize the study area into regular spatial grid cells according to the set grid spacing.
[0039] Step 101: Determine a grid node based on a spatial network unit.
[0040] Step 102: Read the infrasound waveform from the sensor of the station and pre-process the infrasound waveform.
[0041] Step 103 : Based on the infrasound velocity and the distance between each grid node and the station, the pre-processed infrasound waveform is back-projected to obtain a back-projected infrasound waveform.
[0042] Step 104: Apply a Hilbert transform to the back-projected infrasound waveform to extract the envelope energy, thereby obtaining the infrasound waveform envelope corresponding to each grid node when it is a potential infrasound source. This step can highlight the energy concentration in the waveform.
[0043] Step 105: Stack the infrasound waveform envelopes to obtain a stacking value for each grid node, and use the grid node corresponding to the maximum stacking value as the preliminary located infrasound source position.
[0044] Step 106 : With the initially located infrasound source as the center, a set shape with a length of n times the set grid spacing is used as a new research area, and the process returns to step 100 to obtain the infrasound source position.
[0045] Step 107 : Within the set infrasound velocity range, a new infrasound velocity is selected according to the set gradient, and the process returns to step 103 to obtain a plurality of new infrasound source positions.
[0046] Step 108 : Compare the infrasound source position and the stacked values of the multiple new infrasound source positions, and use the infrasound source position corresponding to the maximum stacked value as the final infrasound source position to locate the infrasound event.
[0047] By implementing the above steps 100 to 108 , the present application can ensure the accuracy of infrasound event positioning when only a single sensor is deployed at the station.
[0048] In another exemplary embodiment of the present application, the actual research area is a continuous medium, and the infrasound source position is a certain point in the research area. By gridding, the continuous medium can be discretized into multiple small units (such as Figure 2 The gridding process actually discretizes the study area, providing a discrete computational framework for the subsequent infrasound envelope offset superposition. Therefore, in implementing step 100 of this application, discretizing the study area into regular spatial grid cells must meet two basic requirements: first, the grid resolution must be sufficient to capture the minimum wavelength characteristics of infrasound waves; second, the computational domain must cover all possible sound source locations. Therefore, setting the grid spacing is crucial. Figure 2 The receiving sites correspond to the stations.
[0049] Based on the above description, in this embodiment, to accurately resolve potential source locations at each grid node, the distance between grids must be less than the distance each acoustic waveform sample travels. This means that if the acoustic wave propagation speed is known, the grid spacing should be set based on the maximum distance the sound wave propagates. A smaller grid spacing can improve source localization resolution, but it also increases computational complexity and time. For example, in a typical infrasound monitoring scenario, assuming an infrasound frequency of 1 Hz and a speed of 340 m / s, the wavelength is approximately 340 m. According to the Nyquist sampling theorem, the grid spacing should be less than half the wavelength, or less than 170 m. However, to further improve positioning accuracy, a smaller grid spacing, such as 50 m or 100 m, is typically selected. While a smaller grid spacing significantly increases computational effort, it can more accurately capture the propagation characteristics of infrasound waves. Therefore, in practical applications, there is no single criterion for determining grid spacing; a trade-off between computational efficiency and positioning accuracy must be determined based on the specific application requirements.
[0050] In another exemplary embodiment of the present application, in order to improve the accuracy of the data, appropriate data processing is also crucial to the successful application of RTM, especially when the source-receiver distance is large and the waveform may be inconsistent. Based on this, after the spatial grid unit is constructed, it is necessary to read the infrasound waveform data from the known sensors of the station and perform preprocessing. The steps of preprocessing in the above step 102 of the present application include: (1) linear detrending processing, which can remove linear drift in the data (such as instrument baseline drift); (2) Tukey window tapering processing, that is, using Tukey window for tapering to reduce filtering artifacts. The tapering processing can smooth the starting and ending parts of the waveform and avoid spectral leakage caused by sudden truncation; (3) downsampling processing to reduce the amount of data and improve computational efficiency. Downsampling can significantly reduce the resources required for computing while retaining the main characteristics of the signal.
[0051] In another exemplary embodiment of the present application, in order to eliminate the time difference caused by the distance between each sensor and the sound source, in this embodiment, the reverse projection process in the above step 103 is replaced by the following steps 1 and 2.
[0052] Step 1: Determine the propagation time based on the infrasound velocity and the distance between each grid node and the station. The propagation time can be obtained by dividing the distance between each grid node and the station by the infrasound velocity (e.g., 340 m / s).
[0053] Step 2: Use the propagation time as the offset to perform offset processing on the pre-processed infrasound waveform to obtain the back-projected infrasound waveform. That is, the infrasound waveform is offset by the propagation time to complete the back-projection of the infrasound waveform. Figure 3The station receiving waveform (i.e., infrasound waveform) shown in the figure can be obtained by reverse projection as shown in the figure. Figure 4 The back-projected infrasound waveform is shown.
[0054] In another exemplary embodiment of the present application, based on the description of step 105 above, the infrasound waveform envelope of each sensor is stacked to obtain a stacking value for describing the current grid node. Since the infrasound waveform envelope is obtained based on back projection, and the back projection limits the grid nodes used for projection, in this embodiment, the stacked function is the stacking function of the limited grid nodes. Based on this, the stacking function can be used. The infrasound waveform envelopes are stacked to obtain the stacking value of each grid node. Where N is the number of sensors, u i (t) is the i-th infrasound waveform envelope, x is the position of the grid node, A(x,t) is the stacking function, and t is the time variable corresponding to the infrasound waveform envelope. The envelope stacking result is as follows: Figure 5 shown.
[0055] In another exemplary embodiment of the present application, based on the description of steps 100-108 above, two grids are used to locate the infrasound source. The first grid uses a coarser grid (i.e., the spatial grid cells obtained in step 100) to obtain a preliminary infrasound source location to ensure localization efficiency. The second grid uses a finer grid (corresponding to step 106) to obtain a more accurate infrasound source location. Based on this, in actual applications, a square with a length of five times the set grid spacing can be used as a new study area to obtain the second grid.
[0056] In another exemplary embodiment of the present application, in order to avoid the problem of inaccurate positioning results caused by the influence of the propagation medium during the sound source propagation process, the set infrasound speed range used in the above step 107 of the present application can be [320m / s, 360m / s]. Based on this, in actual application, the infrasound speed in step 103 can be replaced with 320m / s, 325m / s, 330m / s, 335m / s, 345m / s, 350m / s, 350m / s, 355m / s, and 360m / s, respectively, and steps 103-105 are repeated to obtain multiple infrasound source positions corresponding to the above-given different infrasound speeds.
[0057] Based on the above description, the method provided in this application utilizes the reverse propagation characteristics of the wave equation to propagate the received signal back to the possible source position, and determines the most likely infrasound source position through superposition and imaging technology.
[0058] To verify the effectiveness of the method provided in this application, a simulation experiment was conducted using a station containing only one sensor. Based on the simulation results, it was found that the infrasound event localization method provided in this application can achieve an azimuth resolution of ±0.5° and is inherently robust to sensor failure.
[0059] Compared with existing infrasound event location methods, this application has the following advantages:
[0060] 1. Existing methods for locating infrasound events use the relative positions and arrival time differences of different elements in an array to determine the event's direction, and then leverage the interaction of directions between multiple arrays to determine the event's location. The method proposed in this application, however, only requires the ability to acquire the infrasound waveforms from sensors at a station to locate infrasound events based on these waveforms. It does not require that the infrasound station be deployed in an array and is applicable to stations with a single sensor.
[0061] 2. Existing infrasound event location methods rely on arrival time differences, requiring detection of infrasound events to determine arrival times. However, the method proposed in this application eliminates this requirement and instead uses waveforms for location. Furthermore, by updating the study area and infrasound velocity, multiple infrasound source locations are determined, and the location corresponding to the maximum stacked value is selected as the final location, ensuring accurate infrasound event location.
[0062] In an exemplary embodiment, a subacoustic event localization system is provided. The subacoustic event localization system may be a Figure 6 The computer device shown. The computer device includes a processor, a memory, an input / output interface (I / O) and a communication interface. The processor, the memory and the input / output interface are connected via a system bus, and the communication interface is connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store infrasound event location data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, an infrasound event location method is implemented.
[0063] Those skilled in the art will understand that Figure 6 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.
[0064] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.
[0065] In an exemplary embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.
[0066] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.
[0067] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (RRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).
[0068] The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may include, but are not limited to, general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic units, data processing logic units based on quantum computing, and the like.
[0069] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0070] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.
Claims
1. A method for locating an infrasound event, characterized in that: Suitable for stations with single sensor deployment; The infrasound event locating method comprises: According to the set grid spacing, the study area is discretized into regular spatial grid cells; determining a grid node based on the spatial network unit; reading an infrasound waveform from a sensor at the station and preprocessing the infrasound waveform; Based on the infrasound velocity and the distance between each grid node and the station, the pre-processed infrasound waveform is back-projected to obtain a back-projected infrasound waveform; The Hilbert transform is used on the back-projected infrasound waveform to extract the envelope energy and obtain the infrasound waveform envelope corresponding to the infrasound station when each grid node is regarded as a potential infrasound source; The infrasound waveform envelopes are stacked to obtain the stacking value of each grid node, and the grid node corresponding to the maximum stacking value is used as the preliminary location of the infrasound source; Taking the initially located infrasound source as the center, a set shape with a length of n times the set grid spacing is used as the new study area, and the step of discretizing the study area into regular spatial grid cells is returned to obtain the infrasound source position; within a set infrasound velocity range, selecting a new infrasound velocity according to a set gradient, and returning to the step of back-projecting the pre-processed infrasound waveform based on the infrasound velocity and the distance between each grid node and the station position to obtain a back-projected infrasound waveform, thereby obtaining a plurality of new infrasound source positions; The infrasound source position and the stacked values of multiple new infrasound source positions are compared, and the infrasound source position corresponding to the maximum stacked value is used as the final infrasound source position to achieve the positioning of the infrasound event.
2. The infrasound event locating method according to claim 1, wherein: The preprocessing methods include: linear detrending processing, Tukey window tapering processing and downsampling processing.
3. The infrasound event locating method according to claim 1, characterized in that: Based on the infrasound velocity and the distance between each grid node and the station, the pre-processed infrasound waveform is back-projected to obtain the back-projected infrasound waveform, including: Determine the propagation time based on the infrasound velocity and the distance between each grid node and the station; The propagation time is used as an offset to perform offset processing on the pre-processed infrasound waveform to obtain a back-projected infrasound waveform.
4. The infrasound event locating method according to claim 1, wherein: The infrasound waveform envelopes are stacked to obtain the stacked value of each grid node, including: Using stacking function The infrasound waveform envelope is stacked to obtain the stacking value of each grid node; where N is the number of sensors, u i (t) is the i-th infrasound waveform envelope, x is the position of the grid node, A(x,t) is the stacking function, and t is the time variable corresponding to the infrasound waveform envelope.
5. The infrasound event locating method according to claim 1, characterized in that: The set shape is a square.
6. The infrasound event locating method according to claim 1, characterized in that: The set infrasonic velocity range is [320m / s, 360m / s].
7. The infrasound event locating method according to claim 1, characterized in that: The set grid spacing is set according to the maximum distance of infrasound propagation.
8. An infrasound event location system, characterized in that: include: processor and memory; The processor is connected to the memory; The memory stores a computer program; The processor executes the computer program to implement the infrasound event localization method according to any one of claims 1 to 7.
9. The infrasound event locating system according to claim 8, characterized in that: The memory is a computer-readable storage medium.