A multi-channel free-assembleable wireless surface wave detection device

Abstract

This utility model discloses a multi-channel, self-organizing wireless surface wave detection device, comprising a host, a central acquisition node, and several acquisition sub-nodes. The host is connected to the central acquisition node, and each acquisition sub-node is wirelessly connected to the central acquisition node. A wireless sensor acquisition system is deployed on both the central acquisition node and each acquisition sub-node. The wireless sensor acquisition system includes a trigger circuit, a sensor, an amplifier circuit, an AD converter, an FPGA, an MCU, and a wireless communication module. The output of the sensor is connected to the input of the amplifier circuit. The input of the AD converter is connected to both the output of the trigger circuit and the output of the amplifier circuit. The output of the AD converter is connected to the FPGA. The FPGA is connected to the amplifier circuit. The MCU is connected to both the FPGA and the wireless communication module. Based on this, this utility model achieves surface wave detection with low latency, strong anti-interference capability, and high testing efficiency.

Description

Technical Field

[0001] This utility model relates to the field of geophysical exploration / engineering testing technology, specifically a multi-channel wireless surface wave detection device capable of free self-organizing a network. Background Technology

[0002] Surface wave instruments, as fundamental shallow seismic acquisition devices, are primarily used in infrastructure construction, resource exploration, environmental monitoring, and disaster early warning. Surface wave exploration mainly utilizes its dispersion characteristics; that is, in a homogeneous, horizontally layered medium, its velocity varies with frequency, and the lower the frequency, the more the propagation velocity is affected by the deeper formation. The basic process mainly includes the following three steps: 1) Obtaining surface wave data of different frequencies through active or passive source observations. 2) Extracting dispersion curves using specific processing methods. 3) Obtaining the two-dimensional shear wave velocity structure through different inversion algorithms, thereby obtaining the medium properties at different depths.

[0003] Currently, surface wave detection systems on the domestic market mainly consist of a main unit, detector, trigger, 12 / 24-channel connection cables, and trigger cables. These devices use traditional wiring methods, which have drawbacks such as inconvenient on-site wiring, signal attenuation and noise over long distances, and low testing efficiency. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, such as inconvenient wiring, signal attenuation over long distances, high noise levels, and low testing efficiency, this invention provides a multi-channel, self-organizing wireless surface wave detection device. Through wireless networking, it achieves surface wave detection with low latency, strong anti-interference capability, and high testing efficiency.

[0005] According to one aspect of this utility model specification, a multi-channel, self-organizing wireless surface wave detection device is provided, comprising a host, a central acquisition node, and several acquisition sub-nodes; the host is connected to the central acquisition node, and each acquisition sub-node is wirelessly connected to the central acquisition node; the central acquisition node and each acquisition sub-node are each equipped with a wireless sensor acquisition system, the wireless sensor acquisition system comprising a trigger circuit, a sensor, an amplifier circuit, an AD converter, an FPGA, an MCU, and a wireless communication module; the output terminal of the sensor is connected to the input terminal of the amplifier circuit, the input terminal of the AD converter is connected to the output terminal of the trigger circuit and the output terminal of the amplifier circuit respectively, the output terminal of the AD converter is connected to the FPGA, the FPGA is connected to the amplifier circuit, and the MCU is connected to the FPGA and the wireless communication module respectively.

[0006] In this invention, the host activates the triggering function of the triggering circuit in the acquisition center node. When the triggering circuit of the acquisition center node acquires a trigger signal, the MCU of the acquisition center node informs each acquisition sub-node to acquire the surface wave vibration signal via the wireless communication module. Each acquisition sub-node acquires the surface wave vibration signal through a sensor, then amplifies the surface wave vibration signal and filters out noise interference through an amplification circuit. Simultaneously, the amplification gain of the amplification circuit is adjusted through an FPGA. After the acquisition is completed, the MCU of the acquisition sub-node transmits the surface wave vibration signal to the acquisition center node via the wireless communication module, and finally, the acquisition center node transmits it to the host via USB.

[0007] Furthermore, the amplification circuit includes a first-stage instrumentation programmable operational amplifier, a Butterworth filter, a second-stage instantaneous floating-point operational amplifier, and an exponent circuit; the output terminal of the sensor is connected to the input terminal of the first-stage instrumentation programmable operational amplifier; the output terminal of the first-stage instrumentation programmable operational amplifier is connected to the input terminal of the Butterworth filter, and the output terminal of the Butterworth filter is connected to the input terminal of the second-stage instantaneous floating-point operational amplifier and the input terminal of the exponent circuit, respectively; the output terminal of the second-stage instantaneous floating-point operational amplifier is connected to the input terminal of the AD converter; the output terminal of the exponent circuit is connected to the input terminal of the FPGA; the output terminal of the FPGA is connected to the gain control terminal of the first-stage instrumentation programmable operational amplifier and the gain control terminal of the second-stage instantaneous floating-point operational amplifier, respectively.

[0008] Furthermore, the wireless sensor acquisition system corresponding to the acquisition center node is the central acquisition system; the wireless sensor acquisition system corresponding to each acquisition sub-node is the sub-acquisition system; and the wireless communication module of the central acquisition system is wirelessly connected to the wireless communication module of each sub-acquisition system.

[0009] Furthermore, the triggering circuit includes a trigger and a filter circuit. The output terminal of the trigger is connected to the input terminal of the filter circuit, and the output terminal of the filter circuit is connected to the input terminal of the AD converter. The triggering function of the trigger is disabled by default. The host is used to activate the triggering function of the trigger in the central acquisition system.

[0010] Furthermore, the wireless sensor acquisition system also includes a GPS timing module, which is connected to the MCU and is used to record the trigger time of the trigger.

[0011] Furthermore, the wireless sensor acquisition system also includes a USB, which is connected to the MCU and is used to establish a connection between the wireless sensor acquisition system and the host.

[0012] Furthermore, the wireless sensor acquisition system also includes an SDRAM, which is connected to the FPGA and is used to store trigger signals and surface wave vibration signals.

[0013] Furthermore, the wireless sensor acquisition system also includes a first FLASH, which is connected to the FPGA and is used to store the FPGA's execution control program.

[0014] Furthermore, the wireless sensor acquisition system also includes a second FLASH, which is connected to the MCU and is used to store the trigger signal and surface wave vibration signal sent by the FPGA.

[0015] The above technical solution connects a PC host to a wireless sensor acquisition system on any acquisition node, making the wireless sensor acquisition system connected to the PC host a central acquisition system and the wireless sensor acquisition systems other than the central acquisition system sub-acquisition systems. The central acquisition system controls each sub-acquisition system to acquire surface wave vibration signals, and receives the surface wave vibration signals acquired by each sub-acquisition system and transmits them to the PC host.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] (1) This application can support rapid deployment. Each acquisition node is independently powered and communicated. No wiring is required. It can be directly thrown or buried, which is convenient and fast. At the same time, it can be dynamically expanded and supports the free addition and removal of nodes. It can be automatically integrated into the system through self-organizing network. The AD converter of each acquisition node is digitized nearby, avoiding distortion of analog signals over long distances.

[0018] (2) By introducing floating-point amplification technology, this application can improve the system resolution without reducing the maximum range that the system can support, thereby improving the dynamic range that the system can support.

[0019] (3) This application uses a wireless self-organizing network combined with a high-precision GPS timing module to achieve microsecond-level synchronization, which improves the accuracy of time triggering. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a wireless networking method provided for an embodiment of the present utility model.

[0021] Figure 2 This is a schematic diagram of the structure of the wireless sensor acquisition system provided in an embodiment of the present invention.

[0022] In the diagram: 100, Wireless sensor acquisition system; 1, Trigger; 2, Filter circuit; 3, Sensor; 4, First-stage instrument programmable operational amplifier; 5, Butterworth filter; 6, Second-stage instantaneous floating-point operational amplifier; 7, Exponent circuit; 8, AD converter; 9, FPGA; 10, MCU; 11, Wireless communication module; 12, GPS timing module; 13, USB; 14, SDRAM; 15, First FLASH; 16, Second FLASH; 200, PC host; 1000, Wireless surface wave detection device. Detailed Implementation

[0023] The technical solutions of various embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0024] Please refer to the appendix. Figure 1 This utility model provides a multi-channel wireless surface wave detection device 1000 that can freely form a network.

[0025] The wireless surface wave detection device 1000 includes a PC host 200 (Personal Computer) and several acquisition nodes. After a acquisition node is successfully connected to the acquisition software on the host 200 and configured, it acts as the acquisition center node, and its trigger function is activated. The trigger 1 is placed near the acquisition center node to receive trigger signals. Other acquisition nodes act as acquisition sub-nodes, wirelessly connected to the acquisition center node and operating under its control. Any acquisition node can be used as either an acquisition sub-node or an acquisition center node, allowing for flexible deployment based on site conditions. The central acquisition node and each acquisition sub-node are equipped with a self-organizing wireless sensor acquisition system 100. The trigger function of each wireless sensor acquisition system 100 is disabled by default.

[0026] The wireless sensor acquisition system 100 includes a trigger circuit, a sensor 3, an amplifier circuit, an AD converter 8 (Analog-to-Digital Converter), an FPGA 9 (Field-Programmable Gate Array), an MCU 10 (Microcontroller Unit), and a wireless communication module 11. The output of the sensor 3 is connected to the input of the amplifier circuit. The input of the AD converter 8 is connected to the output of both the trigger circuit and the amplifier circuit. The output of the AD converter 8 is connected to the FPGA 9, which is connected to the amplifier circuit. The MCU 10 is connected to both the FPGA 9 and the wireless communication module 11.

[0027] By connecting the host to the wireless sensor acquisition system on any acquisition node, the wireless sensor acquisition system corresponding to the central acquisition node is called the central acquisition system. The wireless sensor acquisition system corresponding to each acquisition sub-node is called a sub-acquisition system. The wireless communication module of the central acquisition system is wirelessly connected to the wireless communication module of each sub-acquisition system to realize the transmission of control commands, sampling parameters, and acquisition data between the central acquisition node and each acquisition sub-node. This allows the central acquisition system to control each sub-acquisition system to acquire surface wave vibration signals via the wireless communication module, and to receive the surface wave vibration signals acquired by each sub-acquisition system and transmit them to the PC host 200. It is understood that the wireless sensor acquisition systems deployed on each acquisition node have the same structure; therefore, any acquisition node can be used as both a acquisition sub-node and an acquisition central node, and can be flexibly arranged according to the site conditions, without any limitations here.

[0028] The triggering circuit includes trigger 1 and filter circuit 2. The output of trigger 1 is connected to the input of filter circuit 2, and the output of filter circuit 2 is connected to the input of AD converter 8. The triggering function of trigger 1 is disabled by default. In the central acquisition system, the triggering function of trigger 1 is activated by PC host 200.

[0029] The amplifier circuit is a two-stage amplifier circuit, consisting of a first-stage instrumentation control operational amplifier 4, a Butterworth filter 5, a second-stage instantaneous floating-point operational amplifier 6, and an index circuit 7. The output of sensor 3 is connected to the input of the first-stage instrumentation control operational amplifier 4. The output of the first-stage instrumentation control operational amplifier 4 is connected to the input of the Butterworth filter 5, and the output of the Butterworth filter 5 is connected to both the input of the second-stage instantaneous floating-point operational amplifier 6 and the input of the index circuit 7. The output of the second-stage instantaneous floating-point operational amplifier 6 is connected to the input of the AD converter 8. The output of the index circuit 7 is connected to the input of FPGA 9. The output of FPGA 9 is simultaneously connected to the gain control terminals of both the first-stage instrumentation control operational amplifier 4 and the second-stage instantaneous floating-point operational amplifier 6.

[0030] The wireless sensor acquisition system 100 also includes a GPS timing module 12 (Global Positioning System), a USB 13 (Universal Serial Bus), an SDRAM 14 (Synchronous Dynamic Random-Access Memory), a first FLASH 15, and a second FLASH 16 (Flash Memory). The MCU 10 is connected to the GPS timing module 12, USB 13, and the second FLASH 16, respectively, and the FPGA 9 is connected to the SDRAM 14 and the first FLASH 15, respectively.

[0031] In this embodiment, SDRAM 14 is used to store trigger signals and surface wave vibration signals. The first FLASH 15 is used to store the execution control program of the FPGA 9. The second FLASH 16 is used to store the trigger signals and surface wave vibration signals sent by the FPGA 9; the data in the FLASH is characterized by not being lost when power is off. The high-precision GPS timing module 12 has a built-in time trigger function, used to record the trigger time of each wireless sensor acquisition system 100. The time trigger accuracy is at least 1µs, and it can accurately record the time information of the trigger time. The USB 13 connected to the MCU 10 is used when acting as the acquisition center node. The central acquisition system establishes a connection with the PC host 200 through USB 13, and then communicates with the PC host 200 through USB 13. In this embodiment, the communication rate is as high as 480Mbps.

[0032] Furthermore, the acquisition process of the trigger signal is as follows: the trigger 1 of the acquisition center node acquires the trigger signal (i.e., the analog signal), and filters out interference signals through the filtering circuit 2 (i.e., Butterworth low-pass and high-pass circuits), and then transmits it to the AD converter 8 for analog-to-digital conversion (i.e., digital signal). The FPGA9 reads the trigger signal and compares the amplitude of the trigger signal with the preset trigger level. When the amplitude of the trigger signal reaches the preset trigger level, the FPGA9 notifies the MCU10 to start the triggering process. The MCU10 broadcasts the trigger command to all acquisition sub-nodes through the wireless communication module 11. The acquisition sub-nodes record the trigger time and acquire the surface wave vibration signal.

[0033] Furthermore, the acquisition process of the surface wave vibration signal is as follows: the surface wave vibration signal (i.e., the original analog signal) acquired by the sensor 3 of the acquisition sub-node is amplified by the first-stage instrument programmable operational amplifier 4. This amplification factor can be configured by the acquisition software on the PC host 200 and sent to the acquisition center node. The acquisition center node sends the amplification factor setting to the acquisition sub-node through the wireless communication module 11. The surface wave vibration signal amplified by the first-stage instrument programmable operational amplifier 4 is filtered by the Butterworth filter 5 (i.e., the Butterworth low-pass and high-pass circuit) to remove noise interference and retain the effective signal. Then the denoised signal is transmitted to the index circuit 7. The index circuit 7 compares the signal with the reference level of the comparator (the comparator is the front-end detection unit of the index circuit 7, which directly determines the gain adjustment strategy of the second-stage instantaneous floating-point operational amplifier 6). The output result is input to the FPGA9 for recording. The FPGA9 outputs the corresponding control command to the gain control terminal of the second-stage operational amplifier according to the result, so that signals below the reference level range are amplified by the second-stage floating-point amplifier, while signals outside the reference level range are not amplified. Finally, the output of the second-stage instantaneous floating-point operational amplifier 6 is input to the AD converter 8 for analog-to-digital conversion. The FPGA 9 reads the surface wave vibration signal after analog-to-digital conversion and stores the surface wave vibration signal in SDRAM 14. At the same time, the surface wave vibration signal is transmitted to the second FLASH 16 connected to the MCU 10. After the acquisition is completed, it is transmitted to the acquisition center node according to the self-organizing network protocol. Finally, the acquisition center node transmits it to the PC host 200 via USB 13. The acquisition software on the PC host 200 can read the original acquired signal waveform. The acquisition software also supports data analysis functions and can convert the acquired time-domain amplitude waveform into a dispersion curve.

[0034] Furthermore, the wireless synchronization process of the acquisition nodes involves the following: During the initialization of the multi-channel wireless ad hoc network surface wave detection system, the clocks of the acquisition center node and the acquisition sub-nodes are synchronized using a high-precision GPS timing module. During the operation of the multi-channel wireless ad hoc network surface wave detection system, the trigger is placed near the acquisition center node. When the acquisition center node receives the trigger signal and begins storing, the FPGA9 sends a pulse signal to the GPS timing module 12 to accurately record the sampling instant t1. It also informs the remaining acquisition sub-nodes via the wireless communication module 11. Upon receiving the trigger signal and beginning to acquire the surface wave vibration signal, each acquisition sub-node sends a pulse signal to its internal GPS timing module 12 to record the trigger time t2. After acquisition is completed according to the number of sampling points set in the transmission, the arrival time of the trigger waveform at the acquisition center node t3 and the time t4 of each acquisition sub-node can be determined using the internal sampling interval and the number of sampling points, etc. Where t2-t1 represents the initial time synchronization deviation between the triggering times of the acquisition center node and the acquisition sub-nodes, and t4-t3 represents the wave propagation time difference and the initial time synchronization error. Subtracting the two cancels out the synchronization error, leaving only the wave propagation time difference, thus ensuring absolute synchronization between the acquisition nodes. Therefore, this application can accurately determine the time difference between the arrival of the striking waveform at the acquisition center node and between each acquisition sub-node, achieving high-precision synchronous acquisition by the acquisition device, thereby ensuring the accuracy of problem analysis based on this time difference.

[0035] In summary, the present invention achieves the following:

[0036] First, compared with the current mainstream traditional wired surface wave detection system, the multi-channel wireless self-organizing network surface wave detection system has significant advantages in deployment efficiency, adaptability, and data quality. Traditional wired surface wave detection systems involve complex cabling, requiring the laying of a large number of cables. Furthermore, the fixed number of channels, limited by the number of acquisition station ports, results in poor flexibility. Additionally, parallel laying of long analog wired cables leads to cross-interference, signal attenuation, and synchronization errors. The multi-channel wireless self-organizing network surface wave detection system of this application supports rapid deployment. Each acquisition node has independent power supply and communication, requiring no cabling; it can be directly dropped or buried, making it convenient and quick. It can also be dynamically expanded, supporting the free addition and removal of nodes (up to 64 channels; the maximum number of channels is mainly determined by the channel software address configuration of the wireless communication module 11 and the FLASH capacity connected to the MCU of the acquisition node). Through self-organizing network integration, each acquisition node's ADC digitizes locally, avoiding distortion during long-distance analog signal transmission. The high-precision GPS timing module 12 achieves microsecond-level synchronization (±1µs), with phase consistency superior to wired systems.

[0037] Second, conventional data acquisition systems typically use programmable gain amplifiers at the front end of the channel to improve the resolution of small signals. However, while this improves resolution, it also reduces the full-scale input range of the acquisition system. This application introduces floating-point amplification technology, which can improve system resolution without reducing the maximum range that the system can support, thereby improving the dynamic range that the system can support.

[0038] Third, in conventional wireless networks, there are frequency discrepancies between the clocks of different nodes. The frequency stability and aging characteristics of commonly used temperature-compensated crystal oscillators cannot achieve microsecond-level synchronization, resulting in clock misalignment between each node. This application employs a wireless self-organizing network combined with a high-precision GPS timing module and a synchronization module 12, achieving a time triggering accuracy of at least 1µs.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of this utility model.

Claims

1. A multi-channel, self-organizing wireless surface wave detection device, characterized in that, The system includes a host, a central acquisition node, and several acquisition sub-nodes. The host is connected to the central acquisition node, and each acquisition sub-node is wirelessly connected to the central acquisition node. A wireless sensor acquisition system is deployed on both the central acquisition node and each acquisition sub-node. The wireless sensor acquisition system includes a trigger circuit, a sensor, an amplifier circuit, an AD converter, an FPGA, an MCU, and a wireless communication module. The output of the sensor is connected to the input of the amplifier circuit. The input of the AD converter is connected to both the output of the trigger circuit and the output of the amplifier circuit. The output of the AD converter is connected to the FPGA. The FPGA is connected to the amplifier circuit. The MCU is connected to both the FPGA and the wireless communication module.

2. The multi-channel, self-organizing wireless surface wave detection device according to claim 1, characterized in that, The amplification circuit includes a first-stage instrumentation programmable operational amplifier (IPA), a Butterworth filter, a second-stage instantaneous floating-point operational amplifier (IFPA), and an exponent circuit. The output terminal of the sensor is connected to the input terminal of the first-stage IPA. The output terminal of the first-stage IPA is connected to the input terminal of the Butterworth filter, and the output terminal of the Butterworth filter is connected to the input terminals of the second-stage IFPA and the exponent circuit, respectively. The output terminal of the second-stage IFPA is connected to the input terminal of the AD converter. The output terminal of the exponent circuit is connected to the input terminal of the FPGA. The output terminal of the FPGA is connected to the gain control terminals of the first-stage IPA and the second-stage IFPA, respectively.

3. The multi-channel, self-organizing wireless surface wave detection device according to claim 1, characterized in that, The wireless sensor acquisition system corresponding to the central acquisition node is the central acquisition system; the wireless sensor acquisition system corresponding to each acquisition sub-node is the sub-acquisition system; the wireless communication module of the central acquisition system is wirelessly connected to the wireless communication module of each sub-acquisition system.

4. The multi-channel, self-organizing wireless surface wave detection device according to claim 3, characterized in that, The triggering circuit includes a trigger and a filter circuit. The output terminal of the trigger is connected to the input terminal of the filter circuit, and the output terminal of the filter circuit is connected to the input terminal of the AD converter. The triggering function of the trigger is disabled by default. The host is used to activate the triggering function of the trigger in the central acquisition system.

5. The multi-channel, self-organizing wireless surface wave detection device according to claim 4, characterized in that, The wireless sensor acquisition system also includes a GPS timing module, which is connected to the MCU and is used to record the trigger time of the trigger.

6. The multi-channel, self-organizing wireless surface wave detection device according to claim 1, characterized in that, The wireless sensor acquisition system also includes a USB port, which is connected to the MCU and is used to establish a connection between the wireless sensor acquisition system and the host.

7. The multi-channel, self-organizing wireless surface wave detection device according to claim 1, characterized in that, The wireless sensor acquisition system also includes an SDRAM, which is connected to the FPGA and is used to store trigger signals and surface wave vibration signals.

8. The multi-channel, self-organizing wireless surface wave detection device according to claim 1, characterized in that, The wireless sensor acquisition system also includes a first FLASH, which is connected to the FPGA and is used to store the FPGA's execution control program.

9. The multi-channel, self-organizing wireless surface wave detection device according to claim 1, characterized in that, The wireless sensor acquisition system also includes a second FLASH, which is connected to the MCU and is used to store the trigger signal and surface wave vibration signal sent by the FPGA.

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