Underground fortification detection device and method based on seismic reflected waves

Abstract

The invention discloses an underground fortification detection device and method based on earthquake reflected waves. The detection device comprises an earthquake source drilling bomb, a detection bomb, a local geological structure and an underground fortification. The detection method comprises the following steps: launching a drilling seismic source bomb and scattering a detection bomb; the seismic source drilling bomb drills into the geological structure and starts the first micro seismograph; after the detection bomb falls to the ground, the processor controls the limiting rod to contract through energization of the solenoid, the supporting rod relieves limiting of the limiting rod and opens under torsion of the torsion spring, and the detection bomb is made to be perpendicular to the ground. The processor stores a waveform signal of the second micro seismograph; a controller in the drilling seismic source bomb controls to periodically trigger seismic waves; a reflection interface is formed on the contact surface of the seismic wave and the underground fortification, and a seismic reflection wave is generated; correcting the waveform detected by the detection bomb; and drawing a time distance curve, analyzing the time distance curve, and showing that the underground fortification exists underground at the position corresponding to the terrain at a large waveform change position. The problem that the underground fortification is difficult to identify in the battlefield environment is solved.

Description

Technical Field

[0001] The present invention relates to the field of underground works detection, and in particular to an underground works detection device and method based on seismic reflection waves. Background Art

[0002] In modern warfare, underground facilities have become one of the optional locations for setting up command posts because of their concealment and difficulty in detection. A method is needed to detect the location of enemy underground fortifications to provide guidance and support for our subsequent accurate strikes.

[0003] The main means of target detection at present include satellite telemetry, infrared detection based on drones and other flying platforms, and image recognition. The above methods can usually only identify targets on the ground and cannot penetrate the surface to detect underground buildings. Therefore, a method is needed to detect the location of enemy underground fortifications to provide guidance support for subsequent accurate strikes.

[0004] At present, one method of detecting underground structures is to send a combat team to the underground passage to search and investigate the underground structure; another method is to send small drones and other equipment to the underground passage to search for the location of enemy underground fortifications along the underground pipeline. In the former, in a complex and dark underground environment, the combat team is vulnerable to enemy attacks and personnel injuries, while the latter has problems with drone positioning, navigation and control in a GPS-denied environment and long search times for complex underground structures. In other related fields, the seismic reflection wave method is usually used in geological exploration to map the depth and shape of underground interfaces and explore the location of continental shelf oil and gas fields, but this method usually requires artificial regular arrangement of seismic sources and detectors on the ground, which is not suitable for complex battlefield environments. Summary of the invention

[0005] Purpose of the invention: In order to detect and identify underground fortifications in a battlefield environment, the present invention proposes an underground fortification detection device and method based on seismic reflection waves, and uses the seismic reflection wave method in seismic exploration in combination with the battlefield environment to solve the problem that underground fortifications are difficult to identify in a battlefield environment.

[0006] Technical solution: The underground fortification detection device based on seismic reflection waves of the present invention comprises a seismic drilling source bomb, a detection bomb, a local geological structure and an underground fortification; the warhead of the seismic drilling source bomb is buried under the surface of the ground and contacts the local geological structure and periodically generates seismic waves; the detection bomb is distributed on the surface of the local geological structure and receives the reflected waves of the seismic waves; the underground fortification is buried in the local geological structure;

[0007] The detector bomb includes a detector bomb body, a processor, a second micro-seismograph and a supporting structure; the second micro-seismograph is located at the head of the detector bomb body and sends the received seismic reflection wave to the processor; the supporting structure is located around the detector bomb body and is controlled by the processor;

[0008] The supporting structure includes a supporting rod, a torsion spring, and a spring, a solenoid and a limiting rod located in the detector body; the spring is a compression spring; one end of the limiting rod is a plane in contact with the lower end of the spring, and the other end of the limiting rod is a mortise and tenon structure for limiting the rotation of the supporting rod; the middle part of the limiting rod is a magnetic material; the solenoid is sleeved on the limiting rod; the solenoid generates a magnetic field under the control of the processor to cause the limiting rod to contract, and the supporting rod is stretched open by the torsion spring to make the detector body perpendicular to the ground.

[0009] The seismic source bomb comprises a bomb body, a source generator, a first micro-seismograph and a controller. The source generator is located in the bomb body and is controlled by the controller to generate seismic waves. The micro-seismograph is located in the bomb body to detect seismic waves and transmit them to the controller.

[0010] The detector bombs are distributed on the surface of the local geological structure to form a detector array and receive the reflected waves of seismic waves.

[0011] The projectile body is a ground-penetrating bomb structure that penetrates deep into the ground by breaking through the surface.

[0012] The controller receives, processes and stores the signal from the first micro-seismometer.

[0013] The seismic source generator is installed in the missile body and is controlled by the controller to periodically trigger explosions and generate seismic waves.

[0014] The local geological structure includes the surface and underground soil.

[0015] The underground fortification detection method based on seismic reflection waves of the present invention is implemented by an underground fortification detection device based on seismic reflection waves. The detection method comprises the following steps:

[0016] (1) Launching seismic drilling bombs and scattering detection bombs at the impact point;

[0017] (2) drilling a seismic source bomb into a local geological structure and activating a first micro-seismometer, and a controller records a waveform signal of the first micro-seismometer;

[0018] (3) After the detector bomb lands, the processor in the detector bomb controls the limit rod to retract by energizing the solenoid, and the support rod releases the limit rod and opens under the torsion of the torsion spring, so that the detector bomb is vertical to the ground; the second micro-seismometer works, and the processor stores the waveform signal of the second micro-seismometer;

[0019] (4) The controller controls the source generator to periodically trigger seismic waves and records the detonation time t0 of the source generator; at the same time, the drilling source bomb is wirelessly connected to the detector bomb, and transmits the detonation time t0 and the spatial position coordinates (x i ,t i ,z i );

[0020] (5) The contact surface between the seismic wave and the underground fortification forms a reflection interface and generates seismic reflection waves, which are received and recorded by the seismic source bomb and the detector bomb;

[0021] (6) dividing the waveform signals received by the seismic source bomb and the k detector bombs into two parts according to the detonation time t0, and selecting the signal after time t0 as the useful signal; analyzing the signal of the first part to perform spectrum analysis, obtain the signal characteristics of the environmental noise, and perform signal filtering on the signal characteristics;

[0022] (7) Perform static correction on the waveform detected by the detector to correct the time difference caused by the height difference of the ground. For the i-th detector, the static correction value Δt i静 for:

[0023]

[0024] Among them, h i is the height difference between the ith detector bomb and the seismic source bomb, v is the propagation speed of seismic waves, and v is derived from soil characteristics; according to Δt i静 Add Δt to the time scale of the waveform data of the i-th detector bullet i静 , complete static correction;

[0025] (8) Perform dynamic correction on the waveform of the detector to correct the time difference caused by the spatial position difference between the vibration excitation point and the detection point and the uneven reflection interface. For the i-th detector, the dynamic correction Δt i动 for:

[0026]

[0027] Among them, x i ,y i is the position coordinate of the ith detector missile relative to the seismic source missile on the horizontal plane, v is the propagation velocity of seismic waves, and t' is the time when the seismic source missile detects the seismic reflection wave; Δt is added to the waveform data of the ith detector missile on the time scale i动 , complete dynamic correction;

[0028] (9) Draw a time-distance curve, capture the waveform corresponding to the seismic reflection wave, select sampling points, and connect the sampling points to obtain the time-distance curve of the local terrain;

[0029] (10) Analyzing the time-distance curve, the large waveform changes indicate that there is a large medium change area in the underground within the corresponding position interval of the local terrain, and there are underground fortifications.

[0030] In step (9), the waveform data collected by the seismic source bomb and the detector bomb are analyzed to capture the waveform corresponding to the seismic reflection wave.

[0031] In step (9), the wave crests in the time-distance curve are selected as sampling points, and the sampling points are connected to obtain the time-distance curve of the local terrain.

[0032] Working principle: When the underground fortification device based on seismic reflection waves of the present invention is being tested, the military unit launches a seismic source bomb and randomly scatters a detection bomb near the landing point; the seismic source bomb periodically triggers the sub-warhead to generate seismic waves; the seismic waves propagate underground, and the reflection coefficient is calculated by the formula:

[0033]

[0034] Where R is the reflection coefficient, ρ i , v i , z i are density, wave velocity, and wave impedance under medium i, respectively. It can be seen that when there are different media underground, due to the large difference in their wave impedance, a reflection interface is formed at the boundary of different media. When the seismic wave is transmitted to the reflection interface, reflection will occur, generating seismic reflection waves. The internal medium of the underground fortification is air, which has a different wave impedance from the underground soil. The seismic wave contacts the surface of the underground fortification to generate reflection waves, and the seismic wave that does not contact the underground fortification continues to transmit in the medium; the reflected seismic wave is received and recorded by the drilling seismic source bomb and the detector bomb; the waveform recorded by the drilling seismic source bomb and the detector bomb is analyzed to extract key waveform data; the waveform data is filtered to filter out surface waves, sound waves, and abnormal amplitudes caused by seismic waves and environmental interference; static calibration is performed according to the height difference between the drilling seismic source bomb and the detector bomb to eliminate the detection fluctuation caused by the height; dynamic correction is performed according to the distance between the drilling seismic source bomb and the detector bomb and the time when the drilling seismic source bomb detects the seismic reflection wave to eliminate the waveform change caused by the distance; finally, the reflection wave time-distance curve of the underground structure near the drilling seismic source bomb is obtained, and the location of the underground fortification is determined.

[0035] Beneficial effects: Compared with the prior art, the present invention has the following advantages: The underground fortification detection device and method based on seismic reflection waves of the present invention, according to the different characteristics of underground fortifications and underground soil media, deploys seismic source bombs and detection bombs on the ground, uses seismic reflection waves to directly detect underground structures, and obtains the position coordinates of underground fortifications, thereby realizing underground fortification detection, avoiding personnel injuries that may be caused by enemy attacks during personnel exploration and the time-consuming problem of unmanned equipment underground exploration, and adapts to the complex battlefield environment, providing a solution for underground fortification detection in battlefield environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall structure of the underground fortification detection device based on seismic reflection waves of the present invention;

[0037] Figure 2It is a structural schematic diagram of a seismic source bomb in the underground fortification detection device based on seismic reflection waves of the present invention;

[0038] Figure 3 It is a schematic diagram of the structure of the detector bomb of the underground fortification detection device based on seismic reflection waves of the present invention;

[0039] in, Figure 3 (a) is a front view of the detector bomb support structure of the present invention when it is folded;

[0040] Figure 3 (b) is a front view of the detector bomb support structure of the present invention when it is opened;

[0041] Figure 3 (c) is a partial cross-sectional view of the support structure portion (stowed state) of the detector bomb of the present invention;

[0042] Figure 3 (d) is a partial cross-sectional view of the support structure portion (in an open state) of the detector bomb of the present invention;

[0043] Figure 4 A schematic diagram of a local underground structure and underground works point in an embodiment of the underground works detection method based on seismic reflection waves of the present invention;

[0044] Figure 5 It is a diagram of the implementation process of an embodiment of the underground fortification detection method based on seismic reflection waves of the present invention;

[0045] in, Figure 5 (a) is a schematic diagram of our deployment of seismic source bombs and detector bombs to the target area;

[0046] Figure 5 (b) is a schematic diagram showing the seismic source bomb drilling into the ground, the detector bomb opening the support structure, and the entire system in working condition;

[0047] Figure 5 (c) is a schematic diagram of the drilling source bomb periodically inducing seismic waves and communicating with the source bomb;

[0048] Figure 5 (d) is a schematic diagram of the seismic wave being transmitted to the surface of the underground fortification, where it is emitted, and the reflected wave is generated and received by the detector bomb;

[0049] Figure 6 A data processing flow chart of an embodiment of a data-driven semi-physical simulation test system of the present invention;

[0050] in, Figure 6 (a) is a waveform diagram of seismic reflection waves detected by a seismic source bomb and multiple detector bombs;

[0051] Figure 6(b) is a waveform diagram of seismic reflection waves detected by a drilling source bomb and multiple detector bombs after static correction;

[0052] Figure 6 (c) A waveform diagram of seismic reflection waves obtained by drilling seismic source bombs and multiple detector bombs after static correction and dynamic correction;

[0053] Figure 6 (d) is a time-distance curve diagram of the seismic reflection wave correction waveform obtained by detecting the seismic source bomb and multiple detector bombs, wherein the horizontal axis represents the horizontal distance l between each detector bomb and the seismic source bomb, and the vertical axis represents the time t;

[0054] Figure 6 (e) is the time-distance curve obtained by combining the waveform data of all detector bullets after correction. DETAILED DESCRIPTION

[0055] like Figure 1 As shown, the underground fortification detection device based on seismic reflection waves of the present invention comprises a seismic drilling source bomb 1, a detector bomb 2, a local geological structure 3 and an underground fortification 4. In the embodiment, the seismic drilling source bomb 1 is a ground-penetrating bomb carrying an alphabetical warhead, the warhead is buried deep below the surface and directly contacts the soil in the local geological structure 3, and periodically generates seismic waves; the detector bombs 2 are randomly distributed on the surface of the local geological structure, forming a detector array, and receiving the reflected waves of the seismic waves; the underground fortification 4 is buried in the local geological structure 3.

[0056] like Figure 2 As shown, the seismic source bomb 1 includes a bomb body 11, a source generator 12, a first micro-seismograph 13 and a controller 14. The bomb body 11 is a ground-penetrating bomb structure, which penetrates into the ground by breaking the surface; the source generator 12 is installed inside the bomb body 11, and is controlled by the controller 14 to periodically trigger small equivalent explosions to generate seismic waves; the first micro-seismograph 13 is installed inside the bomb body 11, and then detects seismic wave signals and transmits them to the controller 14; the controller 14 controls the source generator 12 to generate seismic waves, and has the ability to receive, process, and store signals from the first micro-seismograph 13, as well as the ability to wirelessly communicate with the detector bomb 2.

[0057] like Figure 3As shown, the detector bomb 2 includes a detector bomb body 21, a processor 22, a second micro-seismograph 23 and a support structure 24. The support structure 24 is composed of a spring 25, a solenoid 26, a limit rod 27, a support rod 28 and a torsion spring 29. The size of the detector bomb body 21 is consistent with the size of the submunition and is directly installed in the dispenser. The processor 22 has the ability to supply power to the second micro-seismograph 23 and the solenoid 26 and control their operation, and has the ability to receive and store the data collected by the second micro-seismograph 23, as well as spatial positioning and wireless communication capabilities. The second micro-seismograph 23 is installed at the head of the detector body 21, controlled by the processor 22, receives the seismic reflection wave and sends it to the processor 22 for storage; the support structure 24 is arranged around the surface of the detector body 21, and is controlled by the processor 22; the spring 25 is a compression spring, which is initially in a compressed state, providing thrust for the limit rod 27 to ensure that the limit rod 27 remains in an extended state at the beginning; the middle part of the limit rod 27 has a magnetic material; the solenoid 26 is sleeved on the limit rod 27 and does not contact the limit rod 27, and is controlled by the processor 22. After power is turned on, a magnetic field is generated to shrink the limit rod 27; the tail of the limit rod 27 is a planar structure, which always keeps in contact with the spring 25 and is subjected to the pressure provided by the spring 25. The top of the limit rod 27 is a mortise and tenon structure, which contacts the support rod 28 and limits the rotation of the support rod 28. The magnetic material in the middle of the limit rod 27, when the solenoid 26 works, is affected by the magnetic field to drive the limit rod 27 to shrink upward; the role of the magnetic material is to release the limit of the support rod 28. The spring 25, the solenoid 26 and the limit rod 27 are in the cavity of the detector body 21; the limit rod 27 can only move in the extension direction and cannot rotate relative to the detector body 21; the support rod 28 is initially attached to the surface of the detector body 21 and is limited by the limit rod 27. When the limit rod 27 contracts, the support rod 28 is stretched open by the torsion spring 29, so that the detector body 21 is perpendicular to the ground; the torsion spring 29 is initially in a tightened state, and always provides an outward rotation force to the support rod 21.

[0058] like Figure 4 As shown, the local geological structure 3 includes a ground surface 31 and underground soil 32. The ground surface 31 refers to artificially laid items such as asphalt and bricks on the ground surface; and the underground soil 32 is a general geological structure below the ground surface 31.

[0059] like Figure 4 As shown, the underground works 4 are buried in the underground soil 32 of the local geological structure 3. The underground works are artificially constructed and are usually large underground cavities. They have a different wave impedance from the underground soil 32 and have the basic conditions for reflecting seismic waves.

[0060] The underground fortification detection method based on seismic reflection waves in the embodiment of the present invention is as follows: Figure 5 As shown, the following steps are included:

[0061] (1) Figure 5As shown in (a), our military unit launches a seismic source bomb 1 and randomly scatters a detection bomb 2 near the impact point.

[0062] (2) Figure 5 b. The seismic source bomb 1 drills into the local geological structure 3 and starts the first micro-seismometer 13 , and the controller 14 starts to record the waveform signal of the first micro-seismometer 13 .

[0063] (3) Figure 5 b. After the detector bomb 2 falls to the ground, the processor 22 in the detector bomb 2 supplies power to the solenoid 26, which generates a magnetic field, thereby driving the limit rod 27 to contract, and the support rod 28 is released from the limit and opens under the torsion of the torsion spring 29, so that the detector bomb 2 is perpendicular to the ground, and the second micro-seismograph 23 starts to work, and the processor 22 starts to store the waveform signal of the second micro-seismograph 23.

[0064] (4) Figure 5 c. The controller 14 in the seismic source bomb 1 controls the source generator 12 to periodically trigger the seismic wave 5 and records the detonation time t0 of the source generator 12; at the same time, the seismic source bomb 1 establishes a wireless connection with the detector bomb 2 and transmits relevant data to the detector bomb 2, including the detonation time t0 and the spatial position coordinates (x i ,y i ,z i );

[0065] (5) Figure 5 d. The seismic wave 5 contacts the underground fortification 4. Since the underground fortification 4 and the local geological structure 3 are different media, a reflection interface is formed at the contact surface between the two, and a seismic reflection wave 6 is generated. The reflected seismic wave is received and recorded by the seismic source bomb 1 and the detector bomb 2.

[0066] (6) Figure 6 a, the solid origin represents the drilling source bomb 1, and the hollow circle represents the detector bomb 2. First, the key waveform signal is selected and filtered. The waveform signals received by the drilling source bomb 1 and k detector bombs 2 are divided into two parts according to the detonation time t0, and the signal after time t0 is selected as the useful signal; the signal of the first part is analyzed for spectrum analysis to obtain the signal characteristics of the environmental noise, and the noise components in the useful signal are suppressed according to the characteristics to perform signal filtering.

[0067] (7) Figure 6 b. Perform static correction on the waveform detected by detector 2 to correct the time difference caused by the height difference of the ground. For the i-th detector 2, the static correction value Δt i静 for:

[0068]

[0069] where hi is the height difference between the i-th detector bomb 2 and the seismic source bomb 1, v is the propagation speed of seismic waves, and v is known in advance based on soil characteristics. i静 Add Δt to the time scale of the waveform data of the i-th detector 2 i静 , complete the static correction.

[0070] (8) Figure 6 c. Perform dynamic correction on the waveform of detector bomb 2 to correct the time difference caused by the spatial position difference between the vibration excitation point and the detection point and the uneven reflection interface. For the i-th detector bomb 2, the dynamic correction Δt i动 for:

[0071]

[0072] where x i ,y i is the position coordinate of the i-th detector 2 relative to the drilling source 1 on the horizontal plane, v is the propagation velocity of seismic waves, and t' is the time when the drilling source 1 detects the seismic reflection wave. Add Δt to the waveform data of the i-th detector 2 on the time scale i动 , complete the dynamic correction.

[0073] (9) Figure 6 d. Draw the time-distance curve, analyze the waveform data collected by the seismic source bomb 1 and all the detection bombs 2, capture the waveform corresponding to the seismic reflection wave, select the sampling point, select the wave peak as the sampling point in the figure, and connect the sampling points to obtain the time-distance curve of the local terrain.

[0074] (10) Figure 6 e. Analyze the time-distance curve and screen out large waveform changes, such as the intervals l1 and l2 in the figure, which indicates that there is a large medium change area underground within the position interval corresponding to the local terrain, and there are enemy underground fortifications.

Claims

1. An underground fortification detection device based on seismic reflection waves, characterized in that: It comprises a seismic drilling source bomb (1), a detector bomb (2), a local geological structure (3) and an underground fortification (4); the warhead of the seismic drilling source bomb (1) is buried below the surface of the earth and contacts the local geological structure (3) and periodically generates seismic waves; the detector bomb (2) is distributed on the surface of the local geological structure (3) and receives reflected waves of the seismic waves; the underground fortification (4) is buried in the local geological structure (3); The detector bomb (2) comprises a detector bomb body (21), a processor (22), a second micro-seismograph (23) and a support structure (24); the second micro-seismograph (23) is located at the head of the detector bomb body (21) and sends the received seismic reflection wave to the processor (22); the support structure (24) is located around the detector bomb body (21) and is controlled by the processor (22); The support structure (24) comprises a support rod (28), a torsion spring (29), a spring (25), a solenoid (26) and a limit rod (27) located in the detector body (21); the spring (25) is a compression spring; one end of the limit rod (27) is a plane in contact with the lower end of the spring (25), and the other end of the limit rod (27) is a mortise and tenon structure for limiting the rotation of the support rod (28); the middle part of the limit rod (27) is a magnetic material; the solenoid (26) is sleeved on the limit rod (27); the solenoid (26) generates a magnetic field under the control of the processor (22) to cause the limit rod (27) to contract, and the support rod (28) is opened under the drive of the torsion spring (29) to make the detector body (21) perpendicular to the ground.

2. The underground fortification detection device based on seismic reflection waves according to claim 1 is characterized in that: The seismic source bomb (1) comprises a bomb body (11), a seismic source generator (12), a first micro-seismograph (13) and a controller (14); the seismic source generator (12) is located in the bomb body (11) and is controlled by the controller (14) to generate seismic waves; the micro-seismograph (13) is located in the bomb body (11) to detect seismic waves and transmit them to the controller (14).

3. The underground fortification detection device based on seismic reflection waves according to claim 1 is characterized in that: The detector bombs (21) are distributed on the surface of the local geological structure to form a detector array and receive reflected waves of seismic waves.

4. The underground fortification detection device based on seismic reflection waves according to claim 2 is characterized in that: The projectile body (11) is a ground-penetrating projectile structure that penetrates into the ground by breaking through the ground surface.

5. The underground fortification detection device based on seismic reflection waves according to claim 1 is characterized in that: The controller (14) receives, processes and stores the signal of the first micro-seismometer (13).

6. The underground fortification detection device based on seismic reflection waves according to claim 2 is characterized in that: The seismic source generator (12) is installed in the bomb body (11) and is controlled by the controller (14) to periodically trigger explosions and generate seismic waves.

7. The underground fortification detection device based on seismic reflection waves according to claim 1 is characterized in that: The local geological structure (3) includes the ground surface (31) and underground soil (32).

8. A method for detecting underground works based on seismic reflection waves, characterized in that: The underground fortification detection device based on seismic reflection waves according to claim 1 is implemented, and the detection method comprises the following steps: (1) launching a seismic source bomb (1) and scattering a detector bomb (2) at the impact point; (2) drilling a seismic source bomb (1) into a local geological structure (3) and activating a first micro-seismometer (13), and a controller (14) recording a waveform signal of the first micro-seismometer (13); (3) After the detector bomb (2) lands on the ground, the processor (22) in the detector bomb (2) controls the limit rod (27) to contract by energizing the solenoid (26), and the support rod (28) releases the limit of the limit rod (27) and opens under the torsion force of the torsion spring (29), so that the detector bomb (2) is vertical to the ground; the second micro-seismograph (23) works, and the processor (22) stores the waveform signal of the second micro-seismograph (23); (4) The controller (14) controls the source generator (12) to periodically generate seismic waves (5) and records the detonation time t0 of the source generator (12); at the same time, the drilling source bomb (1) is wirelessly connected to the detector bomb (2) and transmits the detonation time t0 and the spatial position coordinates (x) relative to the i-th detector bomb (2) to the detector bomb. i ,y i ,z i ); (5) The contact surface between the seismic wave (5) and the underground fortification (4) forms a reflection interface and generates a seismic reflection wave (6), which is received and recorded by the seismic source bomb (1) and the detector bomb (2); (6) dividing the waveform signals received by the seismic drilling source bomb (1) and the k detector bombs (2) into two parts according to the detonation time t0, and selecting the signal after the time t0 as the useful signal; analyzing the signal of the first part to perform spectrum analysis to obtain the signal characteristics of the environmental noise, and performing signal filtering on the signal characteristics; (7) Perform static correction on the waveform detected by the detector (2) to correct the time difference caused by the height difference of the ground. For the i-th detector (2), the static correction value Δt i静 for: Among them, h i is the height difference between the i-th detector bomb (2) and the seismic source bomb (1), v is the propagation speed of seismic waves, which is derived from soil characteristics; according to Δt i静 Add Δt to the time scale of the waveform data of the i-th detector (2) i静 , complete static correction; (8) Perform dynamic correction on the waveform of the detector (2) to correct the time difference caused by the spatial position difference between the vibration excitation point and the detection point and the uneven reflection interface. For the i-th detector (2), the dynamic correction Δt i动 for: Among them, x i ,y i is the position coordinate of the i-th detector missile 2 relative to the drilling source missile (1) on the horizontal plane, v is the propagation velocity of seismic waves, and t' is the time when the drilling source missile (1) detects the seismic reflection wave; Δt is added to the waveform data of the i-th detector missile (2) on the time scale i动 , complete dynamic correction; (9) Draw a time-distance curve, capture the waveform corresponding to the seismic reflection wave, select sampling points, and connect the sampling points to obtain the time-distance curve of the local terrain; (10) Analyzing the time-distance curve, the large waveform changes indicate that there is a large medium change area in the underground within the corresponding position interval of the local terrain, and there are underground fortifications.

9. The underground fortification detection method based on seismic reflection waves according to claim 8, characterized in that: In step (9), the waveform data collected by the seismic source bomb (1) and the detector bomb (2) are analyzed to capture the waveform corresponding to the seismic reflection wave.

10. The underground fortification detection method based on seismic reflection waves according to claim 8, characterized in that: In step (9), the wave crests in the time-distance curve are selected as sampling points, and the sampling points are connected to obtain the time-distance curve of the local terrain.

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