A method for suppressing equivalent self-noise pressure based on a dual-channel distributed acoustic sensing system

Abstract

This invention discloses an equivalent self-noise suppression method based on a dual-channel distributed acoustic sensing system. Light emitted from a narrow-linewidth laser is split by a first coupler C1. One beam passes through an acousto-optic modulator (AOM) to generate a pulse signal, which is then split into two beams by a second coupler C2. These beams are injected into the sensing fiber via two sets of erbium-doped fiber amplifiers (EDFAs), two sets of filters, two sets of circulators, and a fan-in coupler. The pulsed light undergoes backscattering Rayleigh scattering within the sensing fiber. Based on a dual-channel DAS system, this invention uses two cores of a multi-core fiber as the sensing fiber and multiplexes the two core signals. With a noise correlation coefficient of 0.11, it achieves an equivalent self-noise reduction of 2.54 dB in the 100–1000 Hz frequency band, improving the system's ability to detect weak low-frequency signals.

Description

Technical Field

[0001] This invention belongs to the field of underwater acoustic detection technology of distributed acoustic sensing systems, and specifically relates to an equivalent self-noise pressure suppression method based on a dual-channel distributed acoustic sensing system. Background Technology

[0002] Fiber-optic distributed acoustic sensing (DAS) technology involves injecting a probe pulse laser emitted from the transmitter into a sensing fiber. Due to the influence of impurities in the sensing fiber, the probe light undergoes coherent backscattering with Rayleigh and returns to the transmitter. Phase demodulation of this backscattering yields strain information for any segment of the sensing fiber, allowing for the reconstruction of the acoustic signal. Therefore, the sensing fiber essentially functions as a tightly packed acoustic sensor. DAS offers advantages such as simplified system structure, high spatial resolution, strong resistance to electromagnetic interference, and flexible array configuration, thus providing a novel technological approach for underwater acoustic sensing and detection. Common DAS systems typically use single-mode fiber as the sensing fiber. During long-distance transmission, the backscattered Rayleigh light is extremely weak, resulting in a high equivalent self-noise pressure rating. This limitation restricts the minimum detectable sound pressure level of traditional DAS systems, posing challenges in detecting weak acoustic signals.

[0003] To address the issues of suppressing equivalent self-noise pressure and improving sensitivity in single-mode fiber DAS systems, researchers have improved system performance by introducing special optical fibers, such as continuous scattering enhancement fibers, discrete scattering enhancement fibers with inscribed ultra-weak fiber Bragg gratings (UWFBGs) or scattering enhancement points (SEPs), and fiber sensitization. Continuous scattering enhancement schemes mainly include inscribed continuous gratings and changing fiber doping; however, while enhancing the Rayleigh scattering amplitude, it also leads to a significant increase in optical power loss, greatly reducing the detection distance. UWFBGs have a narrow bandwidth, and in special environments such as high pressure and low temperature, the wavelength of the probe light and the reflected wavelength of the UWFBG will mismatch, resulting in a sensing blind zone, thus limiting their application in special environments such as underwater. Sensitization-enhancing fibers mainly improve the sensitivity of the signal phase to changes in sound pressure through helical winding and secondary coating. Helical winding sensitization-enhancing fibers can significantly reduce the system's equivalent self-noise pressure; however, the diameter of publicly reported helical sensitization structures is no less than 12.5 mm, making them difficult to apply in some applications requiring small-sized hydrophones. Secondary coating for enhanced sensitivity involves coating the surface of an optical fiber with a layer of acoustic pressure-sensitive material to improve acoustic wave detection performance. However, its sensitivity is lower than that of spiral-enhanced optical fiber, making it difficult to meet the requirements.

[0004] Researchers have studied the in-phase superposition of output signals from multiple detection arrays, but their analyses primarily focused on high-frequency land-based signals and neglected noise correlation. In reality, noise is also added together during the superposition process. If the noise of each array element is correlated, the equivalent self-noise pressure (EMB) cannot be suppressed. Furthermore, the underwater noise environment is complex; low-frequency noise from waves, marine life, and other sources can interfere with the detection of low-frequency underwater acoustic signals. Therefore, reducing the system's low-frequency equivalent self-noise pressure can improve the detection performance for weak underwater signals. Summary of the Invention

[0005] To address the issues of high equivalent self-noise pressure (EMB) and insufficient detection capability for weak signals in existing DAS systems, this invention provides an ESB suppression method based on a dual-channel distributed acoustic sensing system. A dual-channel DAS detection and demodulation system is designed to ensure that the same detection pulse light is emitted simultaneously from both channels, which is a prerequisite for subsequent signal superposition. Multi-core fiber (MCF) is used as the sensing fiber, with two channels connected to the DAS module respectively. The two sensing fiber cores transmit in parallel, and each core responds consistently to external disturbances while exhibiting inconsistent noise. By superimposing signals at the same location, the system's ESB is reduced, improving its detection capability for low-frequency weak signals, suppressing the ESB spectral level of the DAS system, lowering the system's ESB, and ensuring the small diameter characteristics of the hydrophone unit. This is of great significance for the detection of low-frequency weak signals.

[0006] To solve the above problems, the technical solution provided by the present invention is as follows:

[0007] This invention provides a method for suppressing equivalent self-noise pressure based on a dual-channel distributed acoustic sensing system, characterized by the following steps:

[0008] Step 1: The light emitted by the narrow-linewidth laser is split by the first coupler C1. One beam passes through the acousto-optic modulator (AOM) to generate a pulse signal, which is then split into two beams by the second coupler C2. These beams are then injected into the sensing fiber via two sets of erbium-doped fiber amplifiers (EDFAs), two sets of filters, two sets of circulators, and a fan-in coupler. The pulsed light undergoes backscattering Rayleigh scattering in the sensing fiber. The splitting ratio of the first coupler C1 is 98:1:1, and the splitting ratio of the second coupler C2 is 1:1.

[0009] Step 2: When the sensing fiber is subjected to sound pressure, the phase of the backscattered light changes, interfering with the two 1% local oscillator beams split from the laser at the third coupler C3 and the fourth coupler C4, respectively. After photoelectric conversion by the first balanced detector BPD1 and the second balanced detector BPD2, the light is acquired by the data acquisition card DAQ. The phase distribution of the scattered light in the entire sensing fiber is obtained through heterodyne phase detection, and the sound pressure fluctuation information can be obtained from the phase difference of the scattered light between different positions. The splitting ratio of the third coupler C3 and the fourth coupler C4 is 1:1.

[0010] Step 3: The sensing fiber is set as a multi-core fiber, with two cores of the multi-core fiber as the sensing fiber, and the two-core space-division signals are multiplexed. With the dual-core signal having a noise correlation coefficient of 0.11, the performance of equivalent self-noise voltage reduction of 2.54dB in the 100-1000Hz frequency band is achieved.

[0011] In a preferred embodiment of the present invention, the number of multi-core optical fibers in step 3 is 7, with core 7 located at the center of the seven cores and the other 6 cores evenly distributed around core 7.

[0012] The phase difference signals demodulated from fiber core 1 and fiber core 2 are superimposed. When the noise of the two fiber cores is completely uncorrelated, the equivalent self-noise pressure of the system after superposition can be reduced by 10lg2 = 3dB. However, in reality, the noise sources of both cores are partly from the same optical device, such as a laser and an acousto-optic frequency shifter. The phase noise generated by the two makes the noise characteristics of the two cores correlated to a certain extent. On the other hand, fiber cores 1 and 2 are in a multi-core optical fiber and are adjacent in position. They have the same response to the surrounding environmental noise and are also correlated. Therefore, the noise correlation coefficient of the two cores is calculated first, and then the actual equivalent self-noise pressure suppression effect after superposition of the two core signals is calculated.

[0013] A preferred embodiment of the present invention further includes: step 4, setting m array element signals s1(t), s2(t), ..., s with consistent sensitivity. m (t) are linearly added, and the average power of the output signal is:

[0014]

[0015] In the formula, 'a' is the proportionality coefficient. Similarly, the average noise power is:

[0016]

[0017] make The average signal-to-noise ratio of the array can be expressed as:

[0018]

[0019] Where, (ρ s ) ij 、(ρ n ) ij Let represent the cross-correlation coefficients of signal and noise between the i-th array element and the j-th array element, respectively.

[0020]

[0021] The gain of the array is the logarithm of the ratio of the summed signal-to-noise ratio to the signal-to-noise ratio of a single array element.

[0022]

[0023] Therefore, the gain after array accumulation depends on the cross-correlation coefficient between the signal and noise elements; when the signal is perfectly correlated but the noise is completely uncorrelated,

[0024]

[0025] The array gain after accumulating m array elements is AG = 10lgm; when the signal is perfectly correlated but the noise is partially correlated.

[0026]

[0027] The array gain is:

[0028] Dual-core signal superposition, i.e., m=2, array gain is

[0029] A preferred embodiment of the present invention further includes: Step 5, noise accumulation gain calculation: Based on the time-domain curves and power spectral density of the dual-core noise and the accumulated noise, the average noise power in the 100Hz~1000Hz frequency band is -66.8159dB, -66.5635dB, and -63.2594dB, respectively; The results of repeating the experiment five times: Calculated by formula (5), the cross-correlation coefficient of the noise is 0.11, that is, the noise has correlation, and the noise increase is calculated to be 3.46dB.

[0030] A preferred embodiment of the present invention further includes: Step 6, equivalent self-noise pressure suppression effect: taking the underwater acoustic pressure frequency of 500Hz as an example, the time-domain signal and PSD curves of the demodulated phase signal before and after accumulation, the PSDs of fiber core 1 and fiber core 2 and the accumulated signal frequency points are -52.24dB, -52.25dB, and -46.25dB, respectively, with an average improvement of about 5.995dB; according to the experimental results of multiple frequency points: the PSD of the accumulated signal frequency points actually increases by about 6dB, with an average of about 5.99dB, which is consistent with the theoretical derivation;

[0031] Wherein, when the noise cross-correlation coefficient ρ nWhen =0.11, according to equation (9), the theoretical signal-to-noise ratio gain after the dual-core signal accumulation is 2.56dB. Experimental results show that the actual self-noise voltage of the signal after accumulation is reduced by 2.54dB, which is close to the theoretical value.

[0032] This invention provides an electronic device, comprising: at least one memory for storing a computer program; and at least one processor for executing the program stored in the memory. When the program stored in the memory is executed, the processor executes an equivalent self-noise pressure suppression method based on a dual-channel distributed acoustic sensing system as described in the above embodiments.

[0033] This invention provides a computer-readable storage medium storing a computer program that, when executed on a processor, causes the processor to perform an equivalent self-noise suppression method based on a dual-channel distributed acoustic sensing system as described in the above embodiments.

[0034] Compared with existing technologies, this invention provides an equivalent self-noise pressure suppression method based on a dual-channel distributed acoustic sensing system, which has the following beneficial effects: This invention is based on a dual-channel DAS system, using two cores of a multi-core optical fiber as sensing fibers, and multiplexing the two-core spatially divided signals. With a noise correlation coefficient of 0.11 for the dual-core signals, it achieves a 2.54dB reduction in equivalent self-noise pressure within the 100-1000Hz frequency band, which can improve the system's ability to detect weak low-frequency signals. The suppression of equivalent self-noise pressure is of great significance for improving the accuracy of the system's vibration signal reconstruction and enhancing the system's ability to detect weak low-frequency signals underwater. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments or prior art, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the corresponding system framework for an equivalent self-noise pressure suppression method based on a dual-channel distributed acoustic sensing system, provided in an embodiment of this application.

[0037] Figure 2 This is a schematic diagram of a multi-core sensing fiber connection based on a fan-in / out coupler, provided for an embodiment of this application.

[0038] Figure 3 This is a schematic diagram of the multi-core fiber distribution of a sensing fiber provided in an embodiment of this application.

[0039] Figure 4 A schematic diagram of the time-domain curves of dual-core noise and accumulated noise provided in the embodiments of this application.

[0040] Figure 5 This is a schematic diagram of the power spectral density curves of dual-core noise and accumulated noise provided in the embodiments of this application.

[0041] Figure 6 This is a schematic diagram of the time-domain signal curves before and after the demodulated phase signal is accumulated, taking an underwater acoustic pressure frequency of 500Hz as an example, as provided in the embodiments of this application.

[0042] Figure 7 This is a schematic diagram of the PSD curves of the demodulated phase signal before and after accumulation, taking an underwater acoustic pressure frequency of 500Hz as an example, as provided in an embodiment of this application. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0044] refer to Figure 1 This invention provides a method for suppressing equivalent self-noise pressure based on a dual-channel distributed acoustic sensing system, comprising the following steps:

[0045] Step 1: The light emitted by the narrow-linewidth laser is split by the first coupler C1. One beam passes through the acousto-optic modulator (AOM) to generate a pulse signal, which is then split into two beams by the second coupler C2. These beams are then injected into the sensing fiber via two sets of erbium-doped fiber amplifiers (EDFAs), two sets of filters, two sets of circulators, and a fan-in coupler (Fan-in Coupler). The pulsed light undergoes backscattering Rayleigh scattering in the sensing fiber. The splitting ratio of the first coupler C1 is 98:1:1, and the splitting ratio of the second coupler C2 is 1:1. In this embodiment, the fan-in coupler (Fan-in Coupler) is optically connected to the multi-core fiber (MCF).

[0046] Step 2: When the sensing fiber is subjected to sound pressure, the phase of the backscattered light changes, interfering with the two 1% local oscillator beams split from the laser at the third coupler C3 and the fourth coupler C4, respectively. After photoelectric conversion by the first balanced detector BPD1 and the second balanced detector BPD2, the light is acquired by the data acquisition card DAQ. The phase distribution of the scattered light in the entire sensing fiber is obtained through heterodyne phase detection, and the sound pressure fluctuation information can be obtained from the phase difference of the scattered light between different positions. The splitting ratio of the third coupler C3 and the fourth coupler C4 is 1:1.

[0047] Step 3: The sensing fiber is set as a multi-core fiber, with two cores of the multi-core fiber as the sensing fiber, and the two-core space-division signals are multiplexed. With the dual-core signal having a noise correlation coefficient of 0.11, the performance of equivalent self-noise voltage reduction of 2.54dB in the 100-1000Hz frequency band is achieved.

[0048] refer to Figure 2 and Figure 3 In step 3, there are 7 multi-core optical fibers, with Core 7 located at the center of the seven fibers and the other 6 fibers evenly distributed around Core 7. The sensing fiber is a multi-core fiber. The phase difference signals demodulated from core 1 and core 2 are superimposed. When the noise of the two fibers is completely uncorrelated, the equivalent self-noise pressure of the system after superposition can be reduced by 10lg2 = 3dB. However, in reality, the noise sources of both fibers are partly from the same optical device, such as a laser and an acousto-optic frequency shifter. The phase noise generated by these two devices makes the noise characteristics of the two fibers correlated. On the other hand, core 1 and core 2 are in a multi-core fiber and are adjacent in position. They have the same response to the surrounding environmental noise and are also correlated. Therefore, the correlation coefficient of the two fibers is calculated first, and then the actual equivalent self-noise pressure suppression effect after the two-core signals are superimposed is calculated.

[0049] A method for suppressing equivalent self-noise pressure based on a dual-channel distributed acoustic sensing system further includes: Step 4, assuming m array element signals with consistent sensitivity s1(t), s2(t), ..., s m (t) are linearly added, and the average power of the output signal is:

[0050]

[0051] In the formula, 'a' is the proportionality coefficient. Similarly, the average noise power is:

[0052]

[0053] make The average signal-to-noise ratio of the array can be expressed as:

[0054]

[0055] Where, (ρ s ) ij 、(ρ n ) ij Let represent the cross-correlation coefficients of signal and noise between the i-th array element and the j-th array element, respectively.

[0056]

[0057] The gain of the array is the logarithm of the ratio of the summed signal-to-noise ratio to the signal-to-noise ratio of a single array element.

[0058]

[0059] Therefore, the gain after array accumulation depends on the cross-correlation coefficient between the signal and noise elements; when the signal is perfectly correlated but the noise is completely uncorrelated,

[0060]

[0061] The array gain after accumulating m array elements is AG = 10lgm; when the signal is perfectly correlated but the noise is partially correlated.

[0062]

[0063] The array gain is:

[0064] Dual-core signal superposition, i.e., m=2, array gain is

[0065] A method for suppressing equivalent self-noise pressure based on a dual-channel distributed acoustic sensing system further includes: Step 5, noise accumulation gain calculation: based on the time-domain curves of the dual-core noise and the accumulated noise ( Figure 4 ) and power spectral density ( Figure 5 The average noise power in the 100Hz-1000Hz frequency band was -66.8159dB, -66.5635dB, and -63.2594dB, respectively. The results of five repeated experiments (Table 1) show that the cross-correlation coefficient of the noise is 0.11, indicating that the noise is correlated. The calculated noise increase is 3.46dB. As shown in Table 2, the actual average PSD of the accumulated noise is 3.46dB, which is consistent with the calculated value.

[0066] Table 1. Noise PSD (dB / Hz) before and after dual-core signal accumulation

[0067]

[0068] A method for suppressing equivalent self-noise pressure based on a dual-channel distributed acoustic sensing system further includes: Step 6, the equivalent self-noise pressure suppression effect: taking a water acoustic pressure frequency of 500Hz as an example, the time domain signals before and after the demodulated phase signals are accumulated ( Figure 6 ) and PSD curves ( Figure 7 The PSDs of fiber core 1, fiber core 2, and the accumulated signal frequencies are -52.24dB, -52.25dB, and -46.25dB, respectively, with an average improvement of about 5.995dB. According to the experimental results of multiple frequencies (Table 2), the PSD of the accumulated signal frequencies actually increased by about 6dB, with an average of about 5.99dB, which is consistent with the theoretical derivation.

[0069] Table 2. PSD data (dB / Hz) at various frequency points before and after dual-core signal accumulation.

[0070]

[0071] Wherein, when the noise cross-correlation coefficient ρ n When = 0.11, according to equation (9), the theoretical signal-to-noise ratio gain after the dual-core signal accumulation is 2.56dB. The experimental results (Table 3) show that the actual equivalent self-noise pressure of the accumulated signal is reduced by 2.54dB, which is close to the theoretical value. Suppressing the equivalent self-noise pressure of the system is of great significance for improving the accuracy of the system's vibration signal reconstruction and enhancing the system's ability to detect weak low-frequency underwater signals.

[0072] Table 3. Signal-to-noise ratio (SNR) data at various frequency points before and after dual-core signal accumulation (dB)

[0073]

[0074] This invention is based on a dual-channel DAS system, using two cores of a multi-core optical fiber as sensing fibers and multiplexing the two-core spatially divided signals. With a noise correlation coefficient of 0.11, it achieves a 2.54 dB reduction in equivalent self-noise voltage within the 100-1000 Hz frequency band, improving the system's ability to detect weak low-frequency signals. Suppressing the system's equivalent self-noise voltage is crucial for improving the accuracy of vibration signal reconstruction and enhancing the system's ability to detect weak low-frequency signals underwater.

[0075] This invention provides an electronic device, comprising: at least one memory for storing a computer program; and at least one processor for executing the program stored in the memory. When the program stored in the memory is executed, the processor executes an equivalent self-noise pressure suppression method based on a dual-channel distributed acoustic sensing system as described in the above embodiments.

[0076] This invention provides a computer-readable storage medium storing a computer program that, when executed on a processor, causes the processor to perform an equivalent self-noise suppression method based on a dual-channel distributed acoustic sensing system as described in the above embodiments.

[0077] Although the present invention has been disclosed above with reference to preferred embodiments, the above preferred embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A method for suppressing equivalent self-noise pressure based on a dual-channel distributed acoustic sensing system, characterized in that, Includes the following steps: Step 1: The light emitted by the narrow-linewidth laser is split by the first coupler C1. One beam passes through the acousto-optic modulator (AOM) to generate a pulse signal, which is then split into two beams by the second coupler C2. These beams are then injected into the sensing fiber connected by two sets of erbium-doped fiber amplifiers (EDFAs), two sets of filters, two sets of circulators, and a fan-in coupler. The pulsed light undergoes backscattering Rayleigh scattering in the sensing fiber. The splitting ratio of the first coupler C1 is 98:1:1, and the splitting ratio of the second coupler C2 is 1:

1. Step 2: When the sensing fiber is subjected to sound pressure, the phase of the backscattered light changes, interfering with the two 1% local oscillator beams split from the laser at the third coupler C3 and the fourth coupler C4, respectively. After photoelectric conversion by the first balanced detector BPD1 and the second balanced detector BPD2, the light is acquired by the data acquisition card DAQ. The phase distribution of the scattered light in the entire sensing fiber is obtained through heterodyne phase detection, and the sound pressure fluctuation information can be obtained from the phase difference of the scattered light between different positions. The splitting ratio of the third coupler C3 and the fourth coupler C4 is 1:

1. Step 3: The sensing fiber is set with a multi-core fiber. Two cores of the multi-core fiber are used as sensing fibers, and the two-core space-division signals are multiplexed. With a noise correlation coefficient of 0.11, the equivalent self-noise voltage reduction of 2.54dB in the 100-1000Hz frequency band is achieved. In step 3, there are 7 multi-core optical fibers. Core 7 is located at the center of the seven fibers, and the other 6 fibers are evenly distributed around Core 7. The phase difference signals demodulated from fiber core 1 and fiber core 2 are superimposed. When the noise of the two fiber cores is completely uncorrelated, the equivalent self-noise pressure of the system after superposition can be reduced by 10lg2 = 3dB. However, in reality, the noise sources of both cores are partly from the same optical device, and the phase noise generated by the two makes the noise characteristics of the two cores correlated to a certain extent. On the other hand, fiber cores 1 and 2 are in a multi-core optical fiber and are adjacent in position. They have the same response to the surrounding environmental noise and are also correlated. Therefore, the noise correlation coefficient of the two cores is calculated first, and then the actual equivalent self-noise pressure suppression effect after the two core signals are superimposed is calculated based on this.

2. The method for suppressing equivalent self-noise pressure based on a dual-channel distributed acoustic sensing system according to claim 1, characterized in that, It also includes: Step 4, assuming m array element signals with consistent sensitivity s1(t), s2(t), ..., s m (t) are linearly added, and the average power of the output signal is: In the formula, 'a' is the proportionality coefficient. Similarly, the average noise power is: make The average signal-to-noise ratio of the array can be expressed as: Where, (ρ s ) ij 、(ρ n ) ij Let represent the cross-correlation coefficients of signal and noise between the i-th array element and the j-th array element, respectively. The gain of the array is the logarithm of the ratio of the summed signal-to-noise ratio to the signal-to-noise ratio of a single array element. Therefore, the gain after array accumulation depends on the cross-correlation coefficient between the signal and noise elements; when the signal is perfectly correlated but the noise is completely uncorrelated, The array gain after accumulating m array elements is AG = 10lgm; when the signal is perfectly correlated but the noise is partially correlated. The array gain is: Dual-core signal superposition, i.e., m=2, array gain is 3. The method for suppressing equivalent self-noise pressure based on a dual-channel distributed acoustic sensing system according to claim 2, characterized in that, It also includes: Step 5, noise accumulation gain calculation: According to the time domain curve and power spectral density of the dual-core noise and the accumulated noise, the average noise power in the 100Hz~1000Hz frequency band is -66.8159dB, -66.5635dB, and -63.2594dB, respectively; The results of repeating the experiment five times: According to the calculation of formula (5), the cross-correlation coefficient of the noise is 0.11, that is, the noise has correlation. According to the calculation, the noise increase is 3.46dB.

4. The method for suppressing equivalent self-noise pressure based on a dual-channel distributed acoustic sensing system according to claim 3, characterized in that, It also includes: Step 6, equivalent self-noise pressure suppression effect: Taking the underwater acoustic pressure frequency of 500Hz as an example, the time domain signal and PSD curves of the demodulated phase signal before and after accumulation, the PSD of fiber core 1, fiber core 2 and the accumulated signal frequency points are -52.24dB, -52.25dB and -46.25dB respectively, with an average improvement of 5.995dB; According to the experimental results of multiple frequency points: the PSD of the accumulated signal frequency points actually increased by 6dB, which is consistent with the theoretical derivation; Wherein, when the noise cross-correlation coefficient ρ n When =0.11, according to equation (9), the theoretical signal-to-noise ratio gain after the dual-core signal accumulation is 2.56dB. Experimental results show that the actual self-noise voltage of the signal after accumulation is reduced by 2.54dB, which is close to the theoretical value.

5. An electronic device, characterized in that, include: At least one memory for storing computer programs; At least one processor is configured to execute a program stored in the memory, wherein when the program stored in the memory is executed, the processor is configured to execute an equivalent self-noise suppression method based on a dual-channel distributed acoustic sensing system as described in any one of claims 1 to 4.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is run on the processor, the processor performs an equivalent self-noise suppression method based on a dual-channel distributed acoustic sensing system as described in any one of claims 1 to 4.

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