Automatic Adjustment Method and System for Sampling Delay of Time-Division Multiplexed Fiber Optic Hydrophone Array

Abstract

The present application relates to the technical field of time-division multiplexing fiber optic hydrophones, and specifically to a method and system for automatically adjusting the sampling delay of a time-division multiplexing fiber optic hydrophone array. The method for automatically adjusting the sampling delay of a time-division multiplexing fiber optic hydrophone array includes: S1: obtaining the optical signal output by the time-division multiplexing fiber optic hydrophone array; S2: determining the target sampling delay based on the sliding window technology and the optical signal, where the target sampling delay is the difference between the moment when the time-division multiplexing fiber optic hydrophone array receives the optical pulse and the moment when the output optical signal is sampled; S3: determining the error ratio corresponding to the target sampling delay based on the target sampling delay and the optical signal; S4: when the error ratio is greater than a preset value, adjusting the target sampling delay based on the sliding window technology and the optical signal. Automatic correction and adjustment of the target sampling delay is achieved without manual calibration, thereby improving the accuracy of the target sampling delay and enhancing the automation level of the system.

Description

Technical Field

[0001] This application relates to the field of time-division multiplexing fiber optic hydrophone technology, specifically to a method and system for automatically adjusting the sampling delay of a time-division multiplexing fiber optic hydrophone array. Background Technology

[0002] Fiber optic hydrophones are a type of underwater acoustic detection method based on fiber optic sensing technology. In practical applications, multiple hydrophones are typically arranged into an array to obtain array processing gain and improve detection performance. In recent years, the demand for marine underwater acoustic detection has grown rapidly, and the scale of fiber optic hydrophone arrays has also been continuously increasing. Time-division multiplexing (TDM) technology based on pulsed light transmission and reception is a commonly used technique for increasing the array size of fiber optic hydrophone array systems. Multiple hydrophone probes share the same optical fiber for optical pulse signal transmission. The system ensures that the multiple optical pulses do not overlap in the time domain through precisely set delays. This approach has advantages such as fewer fiber cores and lower cost of optoelectronic modulation and demodulation systems. Simultaneously, the receiver of the fiber optic hydrophone needs to perform precise sampling delay control on the multiple time-division multiplexed pulsed light signals in the same fiber to achieve accurate and reliable de-time-division multiplexing.

[0003] Existing fiber optic hydrophone time-division array systems are generally deployed on shore-based fixed arrays or ship-mounted towed arrays. The sampling delay of time-division multiplexed pulse optical signals is typically manually calibrated before shipment or manually modified during equipment inspection. During system operation, the sampling delay is generally assumed to be a fixed value that does not require adjustment. However, as more and more underwater unmanned exploration platforms are equipped with fiber optic hydrophone arrays for deep-sea acoustic detection, the parameters of the fiber optic hydrophone arrays may change with environmental factors such as water depth, hydrostatic pressure, and temperature. The method of manually calibrating the sampling delay of time-division multiplexed channels is no longer sufficient to meet the requirements of long-term intelligent and autonomous operation of unmanned platforms.

[0004] Therefore, a time delay adjustment method is urgently needed to solve the above problems. Summary of the Invention

[0005] This application provides a method and system for automatically adjusting the sampling delay of a time-division multiplexed fiber optic hydrophone array, so as to realize the automatic correction and adjustment of the target sampling delay without manual calibration, thereby improving the accuracy of the target sampling delay and enhancing the automation level of the system.

[0006] In some embodiments, an automatic adjustment method for sampling delay of a time-division multiplexed fiber optic hydrophone array is provided, comprising: S1: acquiring the optical signal output by the time-division multiplexed fiber optic hydrophone array; S2: determining a target sampling delay based on sliding window technology and the optical signal, wherein the target sampling delay is the difference between the time when the time-division multiplexed fiber optic hydrophone array receives an optical pulse and the time when it samples the output optical signal; S3: determining the error ratio corresponding to the target sampling delay based on the target sampling delay and the optical signal; S4: adjusting the target sampling delay based on sliding window technology and the optical signal when the error ratio is greater than a preset value.

[0007] The automatic adjustment method for sampling delay of time-division multiplexed fiber optic hydrophone arrays provided in this application can determine the target sampling delay based on the optical signal output by the time-division multiplexed fiber optic hydrophone array. If numerous errors occur when sampling using the target sampling delay, the method can automatically adjust the target sampling delay based on the optical signal output by the time-division multiplexed fiber optic hydrophone array, achieving automated adjustment of the target sampling delay. This allows for real-time and accurate measurement and automatic correction of the sampling delay of the time-division multiplexed fiber optic hydrophone array during operation, ensuring the long-term stable operation of the automatic adjustment system. It not only enables unattended measurement and automatic control of time-division pulse sampling delay but also improves the autonomous operation capability of the automatic adjustment system for sampling delay of time-division multiplexed fiber optic hydrophone arrays under different array states, enhancing the system's automation level.

[0008] Optionally, the optical signal includes an optical signal sequence composed of multiple optical signal points; the target sampling delay is determined based on sliding window technology and optical signal, including: determining a first target window based on sliding window detection; the first target window is the optical intensity information of all optical signal points within the sliding window satisfying a first condition; and the starting position of the first target window is taken as the target sampling delay.

[0009] Optionally, the light intensity information includes the average light intensity and variance of all light signal points within the sliding window, with the first condition being that the average light intensity is less than a first average light intensity and the variance is less than a first variance.

[0010] Optionally, determining the first target window based on sliding window detection includes: sliding a sliding window across the optical signal sequence from the initial position of the optical signal sequence, and determining the light intensity information of all optical signal points within the window corresponding to the sliding window; the length of the sliding window is a preset length, which is less than the total number of optical signal points in the optical signal sequence; the step value of the sliding window is a preset step value; and when the light intensity information meets the first condition, stopping the sliding window and determining the sliding window as the first target window.

[0011] Optionally, after sliding a sliding window across the optical signal sequence from the initial position of the optical signal sequence and determining the light intensity information of all optical signal points within the window corresponding to the sliding window, the method further includes: if the light intensity information does not meet the first condition, determining whether the sliding window contains the last optical signal point of the optical signal sequence; if the sliding window contains the last optical signal point of the optical signal sequence, proceeding to step S1; if the sliding window does not contain the last optical signal point of the optical signal sequence, sliding the sliding window according to a preset step value and calculating the light intensity information of all optical signal points within the window of the sliding window.

[0012] Optionally, based on the target sampling delay and the optical signal, the error ratio corresponding to the target sampling delay is determined, including: S31: taking the rising edge of the first pulse in the optical signal as the starting point, after the target sampling delay, a sub-signal interval of a preset length in the optical signal is collected, and a detection record is recorded; S32: calculating the light intensity information in the sub-signal interval; S33: recording an error record if the light intensity information does not meet the first condition; S34: calculating the error ratio of the first number to the second number, where the first number is the number of error records and the second number is the number of detection records.

[0013] Optionally, if the error ratio is greater than a preset value, the target sampling delay is determined based on sliding window technology and optical signals, including: starting from the first target window, sliding the window to continue sliding over the optical signal sequence, and determining the light intensity information of all optical signal points within the window corresponding to the sliding window; if the light intensity information meets the first condition, stopping the sliding window, and determining the sliding window as the second target window; and determining the starting position of the second target window as the target sampling delay.

[0014] Optionally, after determining the error ratio corresponding to the target sampling delay based on the target sampling delay and the optical signal, the method further includes: if the error ratio is less than or equal to a preset value, taking the rising edge of the second pulse in the optical signal as the starting point, after the target sampling delay, acquiring a sub-signal interval of a preset length in the optical signal, recording one detection record, and jumping to step S32.

[0015] Optionally, if the error ratio is greater than a preset value, after adjusting the target sampling delay based on sliding window technology and optical signal, the process further includes: jumping to step S3.

[0016] In some embodiments, an automatic adjustment system for sampling delay of a time-division multiplexed fiber optic hydrophone array is provided, comprising: a laser module configured to output a laser signal to the time-division multiplexed fiber optic hydrophone array according to the basic operating parameters of the array; a time-division multiplexed fiber optic hydrophone array configured to receive the output laser signal and output an optical signal; and a delay detection module configured to: S1: acquire the optical signal output by the time-division multiplexed fiber optic hydrophone array; S2: determine a target sampling delay based on sliding window technology and the optical signal, wherein the target sampling delay is the difference between the time when the time-division multiplexed fiber optic hydrophone array receives the optical pulse and the time when it samples the output optical signal; S3: determine the error ratio corresponding to the target sampling delay based on the target sampling delay and the optical signal; and S4: adjust the target sampling delay based on sliding window technology and the optical signal if the error ratio is greater than a preset value.

[0017] Understandably, the beneficial effects that the technical solution provided by the above-mentioned automatic adjustment system for sampling delay of time-division multiplexing fiber optic hydrophone array can achieve can be found in the beneficial effects of the automatic adjustment method for sampling delay of time-division multiplexing fiber optic hydrophone array and any of its optional implementations, which will not be repeated here. Attached Figure Description

[0018] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A first structural block diagram of the time-division multiplexing fiber optic hydrophone array sampling delay automatic adjustment system provided in the embodiments of this application;

[0020] Figure 2 A second structural block diagram of the time-division multiplexing fiber optic hydrophone array sampling delay automatic adjustment system provided in the embodiments of this application;

[0021] Figure 3 This is a structural block diagram of the delay detection module provided in an embodiment of this application;

[0022] Figure 4 The first flowchart of the automatic adjustment method for sampling delay of time-division multiplexing fiber optic hydrophone array provided in the embodiments of this application;

[0023] Figure 5 A schematic diagram of pulse signals and optical signals provided in the embodiments of this application;

[0024] Figure 6 A schematic diagram of sliding window detection provided in an embodiment of this application;

[0025] Figure 7 The second flowchart is provided for the automatic adjustment method of sampling delay of time-division multiplexing fiber optic hydrophone array provided in the embodiments of this application. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the protection scope of this application.

[0027] In the following description, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0028] Furthermore, in this application, directional terms such as "upper," "lower," "inner," and "outer" are defined relative to the indicated placement of the components in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the placement of the components in the accompanying drawings.

[0029] To facilitate understanding of the technical solution of this application, some concepts involved in this application will be explained below.

[0030] Fiber optic hydrophone: An acoustic sensor based on fiber optic technology used to detect underwater sound wave signals. It utilizes the sensitivity of optical fibers to sound waves, converting the vibration signal of sound waves into a measurable optical signal through the principles of light interference or reflection. Fiber optic hydrophones are widely used in marine exploration, military sonar systems, marine environmental monitoring, and underwater communications.

[0031] Time-division multiplexing fiber optic hydrophone array: A system for underwater acoustic detection utilizing fiber optic technology and time-division multiplexing (TDM) technology. TDM technology allows multiple hydrophones to share the same fiber optic cable for signal transmission, improving system efficiency and data transmission capabilities. A method for assembling multiple fiber optic hydrophones into an array is employed to obtain array processing gain and enhance detection performance.

[0032] To facilitate understanding of the technical solution of this application, the relevant technologies involved in this application will be explained first below.

[0033] In recent years, the demand for marine acoustic detection has grown rapidly, and the scale of fiber optic hydrophone arrays has also been continuously increasing. Time-division multiplexing (TDM) technology based on pulsed light transmission and reception is a commonly used technique for increasing the array size of fiber optic hydrophone array systems. Multiple hydrophone probes share the same optical fiber for optical pulse signal transmission. The system ensures that the multiple optical pulses do not overlap in the time domain through precisely set delays. This approach has advantages such as fewer fiber cores and lower cost of optoelectronic modulation and demodulation systems. Simultaneously, the receiver of the fiber optic hydrophone needs to perform precise sampling delay control on the multiple time-division multiplexed pulsed light signals in the same fiber to achieve accurate and reliable de-time-division multiplexing.

[0034] Existing fiber optic hydrophone time-division array systems are generally deployed on shore-based fixed arrays or ship-mounted towed arrays. The sampling delay of time-division multiplexed pulse optical signals is typically manually calibrated before shipment or manually modified during equipment inspection. During system operation, the sampling delay is generally assumed to be a fixed value that does not require adjustment. However, as more and more underwater unmanned exploration platforms are equipped with fiber optic hydrophone arrays for deep-sea acoustic detection, the parameters of the fiber optic hydrophone arrays may change with environmental factors such as water depth, hydrostatic pressure, and temperature. The method of manually calibrating the sampling delay of time-division multiplexed channels is no longer sufficient to meet the requirements of long-term intelligent and autonomous operation of unmanned platforms.

[0035] Therefore, a method for automatically adjusting the sampling delay is needed to accurately measure the sampling delay of the time-division channel in real time during the operation of the fiber optic hydrophone array and perform automatic correction to ensure the long-term stable operation of the time-division multiplexing system.

[0036] To address the shortcomings of existing technologies, this application provides a method and system for automatically adjusting the sampling delay of a time-division multiplexed fiber optic hydrophone array. This method and system can not only achieve unmanned time-division pulse sampling delay measurement and automatic control, but also improve the autonomous working capability of the time-division multiplexed fiber optic hydrophone array sampling delay automatic adjustment system for different array states, thereby enhancing the system's automation level.

[0037] Figure 1 This is a first structural block diagram of the time-division multiplexing fiber optic hydrophone array sampling delay automatic adjustment system provided in the embodiments of this application.

[0038] Combination Figure 1As shown in the figure, this application provides an automatic sampling delay adjustment system for a time-division multiplexed fiber optic hydrophone array, including: a laser module 1, a time-division multiplexed fiber optic hydrophone array 2, and a delay detection module 3. The laser module 1 is configured to output a laser signal to the time-division multiplexed fiber optic hydrophone array 2 according to its basic operating parameters. The time-division multiplexed fiber optic hydrophone array 2 is configured to receive the output laser signal and output an optical signal. The delay detection module 3 is configured to receive the optical signal output by the time-division multiplexed fiber optic hydrophone array 2 and adjust the target sampling delay in real time based on the optical signal.

[0039] The automatic sampling delay adjustment system for time-division multiplexed fiber optic hydrophone arrays provided in this application embodiment can automatically and in real-time adjust the target sampling delay based on the optical signal output by the time-division multiplexed fiber optic hydrophone array 2. This allows for real-time and accurate measurement and automatic correction of the sampling delay of the time-division channel during the operation of the time-division multiplexed fiber optic hydrophone array 2, ensuring long-term stable operation of the automatic sampling delay adjustment system. It not only enables unattended measurement and automatic control of time-division pulse sampling delay but also enhances the system's autonomous operation capability under different array conditions, thereby improving the system's automation level.

[0040] Figure 2 This is a second structural block diagram of the time-division multiplexing fiber optic hydrophone array sampling delay automatic adjustment system provided in the embodiments of this application.

[0041] Optionally, combined Figure 2 As shown, the time-division multiplexing fiber optic hydrophone array sampling delay automatic adjustment system further includes: a time-division pulse generation module 4, a pulse light modulation module 5, a photoelectric conversion module 6, and a signal acquisition module 7. The time-division pulse generation module 4 is configured to output a pulsed electrical signal to the pulse light modulation module 5 and the delay detection module 3 according to the preset period and preset pulse width of the time-division multiplexing fiber optic hydrophone array 2. The pulse light modulation module 5 receives the laser signal output from the laser module 1 and is configured to modulate the continuous light generated by the laser module 1 into pulsed light with a preset period and preset pulse width according to the pulsed electrical signal. Specifically, the pulse light modulation module 5 turns on the optical output when the pulsed electrical signal is high and turns off the optical output when it is low. The photoelectric conversion module 6 receives the output optical signal from the time-division multiplexing fiber optic hydrophone array 2 and is configured to convert the optical signal into an electrical signal and output the electrical signal to the signal acquisition module 7. The signal acquisition module 7 is configured to acquire the digital signal corresponding to the electrical signal and output the digital signal to the delay detection module 3.

[0042] Specifically, signal acquisition module 7 acquires and digitizes analog electrical signals using an analog-to-digital converter (ADC) chip. For example, signal acquisition module 7 continuously samples the returned interference optical signal of the time-division multiplexed array, starting from any rising edge of a pulse, where the sampling time length is... In this embodiment of the application, it is set It consists of two consecutive pulse repetition cycles, i.e. ADC sampling rate is The number of points obtained from sampling .

[0043] Figure 3 This is a structural block diagram of the delay detection module provided in an embodiment of this application.

[0044] Optionally, combined Figure 3 As shown, the delay detection module 3 includes: ADC data interface module 30, time-division pulse interface module 31, ADC data flow control module 32, ADC data buffer module 33, sliding window data acquisition module 34, first mean and variance calculation module 35, sampling delay judgment module 36, time-division multiplexing demultiplexing module 37, second mean and variance calculation module 38, and sampling delay monitoring module 39.

[0045] The ADC data interface module 30 is configured to receive the digital signal output by the signal acquisition module 7 and transmit the digital signal to the ADC data flow control module 32.

[0046] The time-division pulse interface module 31 is configured to receive the pulse electrical signal output by the time-division pulse generation module 4 and transmit the pulse electrical signal to the ADC data flow control module 32.

[0047] The ADC data flow control module 32 is configured to control the transmission direction of the ADC data flow according to the algorithm logic.

[0048] The ADC data buffer module 33 is configured to buffer the optical signals of two consecutive pulse repetition cycles output by the time-division multiplexed fiber hydrophone array 2. The optical signals are written by the ADC data flow control module 32 and read out by the sliding window data retrieval module 34.

[0049] The sliding window data retrieval module 34 is configured to read optical signal data of a preset length from the ADC data buffer module 33 and output it to the first mean and variance calculation module 35. The preset length is determined by the size of the sliding window.

[0050] The first mean and variance calculation module 35 and the second mean and variance calculation module 38 are both configured to receive optical signal data and calculate the mean and variance of the optical signal data.

[0051] The sampling delay judgment module 36 is configured to determine whether the current position of the sliding window is the first target window based on the mean and variance output by the first mean and variance calculation module 35. If it is the first target window, the sampling delay judgment result will be output to the ADC data flow control module 32, and the sliding window data acquisition module 34 will be notified to stop sliding. If it is not the first target window, the sliding window data acquisition module 34 will be notified to continue sliding.

[0052] The second mean and variance calculation module 38 is configured to receive the optical signal data output by the ADC data stream control module 32, calculate the mean and variance of the optical signal data, and then output it to the sampling delay monitoring module 39.

[0053] The sampling delay monitoring module 39 determines whether there is a problem with the current sampling delay based on the mean and variance output by the second mean and variance calculation module 38, and returns the judgment result to the ADC data flow control module 32.

[0054] The time-division multiplexing module 37 is configured to demodulate the optical signal output by the time-division multiplexed fiber hydrophone array 2 according to the target sampling delay.

[0055] Specifically, the delay detection module 3 is a field-programmable gate array (FPGA), and the ADC data buffer module 33 is implemented by the dual-port RAM resources in the FPGA. It is written by the ADC data flow control module 32 and read out by the sliding window data retrieval module 34.

[0056] Specifically, after the algorithm initialization is completed, the module first enters the first working mode. After detecting the rising edge of the first time-division multiplexing pulse of the optical signal obtained by the time-division pulse interface module 31, it continuously writes an ADC data stream of two consecutive pulse repetition cycles to the ADC data buffer module 33, starting from this rising edge. Then it waits for the output of the sampling delay judgment module 36. After receiving the sampling delay judgment result output by the sampling delay judgment module 36, the ADC data stream control module 32 enters the second working mode. Starting from each rising edge of the time-division multiplexing pulse, after delaying the target sampling delay by a number of clock cycles, it outputs a data stream of the length corresponding to the preset length of the sliding window to the second mean and variance calculation module 38, and simultaneously outputs the subsequent ADC data stream to the de-time-division multiplexing module 37. In the second working mode, the ADC data stream control module 32 will remain in this mode by default and work in a loop. If it receives a delay error indication signal output by the sampling delay monitoring module 39 (output when the error ratio corresponding to the target sampling delay is greater than the preset value), it will re-enter the first working mode from the second working mode.

[0057] Figure 4The first flowchart of the automatic adjustment method for sampling delay of time-division multiplexing fiber optic hydrophone array provided in the embodiments of this application is shown.

[0058] Combination Figures 1 to 3 The embodiment of this application also provides an automatic adjustment system for sampling delay of a time-division multiplexed fiber optic hydrophone array and a delay detection module. The execution entity of this method can be the delay detection module, and it includes steps S1 to S4, as detailed below:

[0059] Step S1: Acquire the optical signal output by the time-division multiplexed fiber optic hydrophone array.

[0060] In this step, the optical signal has two consecutive pulse repetition cycles and is buffered in the ADC data buffer module 33.

[0061] Figure 5 This is a schematic diagram of the pulse signal and optical signal provided in the embodiments of this application. Specifically, Figure 5 (a) shows the optical pulse signal input to the time-division multiplexed fiber optic hydrophone array (above the time axis t). Figure 5 (b) is the optical signal output by the time-division multiplexed fiber optic hydrophone array (below the time axis t). The output optical signal contains a complete preset period and other preset periods.

[0062] Combination Figure 5 As shown, the target sampling delay D in the time-division multiplexed fiber optic hydrophone array is [not specified]. w Subsequently, the time-division multiplexed fiber optic hydrophone array outputs the corresponding optical signal, and the optical signal consists of optical signal segments corresponding to multiple time-division multiplexed channels. For example, in the case where the time-division multiplexed fiber optic hydrophone array contains K time-division multiplexed channels, combined with... Figure 5 As shown in (b), the optical signal includes optical signal segments output by each time-division channel. Figure 5 Figure (b) schematically labels the first time-division channel Q1, the second time-division channel Q2, and the Kth time-division channel Q. K (Corresponding optical signal segment).

[0063] Specifically, the time-division multiplexing fiber optic hydrophone array sampling delay automatic adjustment system provided in this application embodiment is for a time-division system using phase-generated carrier modulation, where the number of time-division multiplexing channels is K and the phase-generated carrier modulation frequency is [missing information]. ,like Figure 5 As shown, after the fiber optic hydrophone array transmits the modulated optical pulse signal, the return light of the time-division multiplexing array is composed of the superposition of pulses from multiple time-division array elements. The sampling delay refers to the time difference between the pulse transmission time and the return time of the first time-division channel pulse.

[0064] Specifically, in combination Figure 5 As shown in (a), the pulse width of the pulse signal is the preset pulse width. The pulse period is a preset period. .in, , . The time delay between each primitive is based on the time-division multiplexing array. Fiber delay line length between individual elements Certainly, exemplary, ,in The speed of light in an optical fiber.

[0065] Step S2: Based on sliding window technology and optical signal, determine the target sampling delay, which is the difference between the time when the time-division multiplexed fiber optic hydrophone array receives the optical pulse and the time when it samples the output optical signal.

[0066] In this step, the initial target sampling delay is determined using sliding window technology and optical signals.

[0067] Combination Figure 5 As shown, Figure 5 D w This is the target sampling delay.

[0068] Optionally, the optical signal includes an optical signal sequence composed of multiple optical signal points; step S2 includes steps S21 and S22, as follows:

[0069] Step S21: Based on sliding window detection, determine the first target window; the first target window is the window where the light intensity information of all light signal points within the sliding window satisfies the first condition.

[0070] In this step, satisfying the first condition indicates that the area inside the sliding window is a dark zone M (e.g., Figure 5 As shown in (b), this indicates that the starting position of the sliding window at this time corresponds to the target sampling delay.

[0071] Optionally, the light intensity information includes the average light intensity and variance of all light signal points within the sliding window, with the first condition being that the average light intensity is less than a first average light intensity and the variance is less than a first variance.

[0072] In this embodiment, by defining a first condition, the window of the sliding window that satisfies the first condition is defined as a dark area.

[0073] For example, the first average light intensity is The first variance is .in, This represents the maximum light intensity of all light signal points within the sliding window. It represents the minimum light intensity of all light signal points within the sliding window.

[0074] Optionally, step S21 includes steps S211 and S212, as follows:

[0075] Step S211: Starting from the initial position of the optical signal sequence, slide a sliding window across the optical signal sequence and determine the light intensity information of all optical signal points within the window corresponding to the sliding window; the length of the sliding window is a preset length, which is less than the total number of optical signal points in the optical signal sequence; the step value of the sliding window is a preset step value.

[0076] For example, preset length The preset step value is 1.

[0077] Step S212: If the light intensity information meets the first condition, stop sliding the window and determine the window as the first target window.

[0078] In this embodiment, by using sliding window detection, the first sliding window that meets the first condition in the optical signal sequence is obtained as the first dark region, and the starting position of the sliding window corresponding to the dark region is the initial target sampling delay, thereby achieving a determined initial target sampling delay.

[0079] Figure 6 This is a schematic diagram of sliding window detection provided in an embodiment of this application.

[0080] For example, the sliding window has a preset length. The corresponding number of optical signal points is L, the preset step value of the sliding window is 1, and the optical signal sequence contains a total of N optical signal points. Combined with... Figure 6 As shown, Figure 6 In (a), the sliding window is located at the initial position of the optical signal sequence. The initial position is when the sliding window includes the first optical signal point to the Lth optical signal point in the optical signal sequence. Figure 6 In (a), the starting position of the sliding window 101 is A1 and the ending position is B1. Figure 6 In section (b), the sliding window moves once according to a preset step value, and then contains the second to the (L+1)th optical signal points within the sliding window. Figure 6 In (b), the starting position of the sliding window 102 is A2 and the ending position is B2. Figure 6 In diagram (c), the case where the sliding window has moved to the last position of the optical signal sequence is represented. The sliding window contains optical signal points NL to N. Figure 6 The starting position of the sliding window 103 in (c) is A3, and the ending position is B3.

[0081] Optionally, after step S211, steps S213 to S215 are also included, as follows:

[0082] Step S213: If the light intensity information does not meet the first condition, determine whether the sliding window contains the last light signal point of the light signal sequence.

[0083] In step S214, if the sliding window contains the last optical signal point of the optical signal sequence, proceed to step S1.

[0084] Step S215: If the sliding window does not contain the last optical signal point of the optical signal sequence, slide the sliding window according to the preset step value and calculate the light intensity information of all optical signal points within the window of the sliding window.

[0085] In this embodiment, if the light intensity information does not meet the first condition, indicating that there is light within the current sliding window, it is necessary to continue sliding the window to find a dark area. However, before continuing to slide the window, it is necessary to determine whether the current optical signal sequence still contains optical signal points that have not entered the sliding window, that is, to determine whether the sliding window contains the last optical signal point of the optical signal sequence. If there are still optical signal points that have not entered the sliding window, the sliding window continues to perform sliding window detection. If there are no optical signal points that have not entered the sliding window, it indicates that the optical signal output by the currently acquired time-division multiplexed fiber optic hydrophone array does not contain a dark area, and it is necessary to acquire the next segment of the optical signal output by the time-division multiplexed fiber optic hydrophone array to continue sliding window detection and determine the target sampling delay.

[0086] For example, combined Figure 6 As shown in (c), the sliding window 103 is already at the last position of the optical signal sequence. The sliding window can no longer slide backward, so it is necessary to acquire the optical signal output by the new time-division multiplexed fiber hydrophone array.

[0087] Step S22: Use the starting position of the first target window as the target sampling delay.

[0088] For example, combined Figure 6 As shown, for example Figure 6 In (b), sliding window 102 is the first target window. Figure 6 The sliding window 102 marked in the figure has a starting position of A2 and an ending position of B2. Therefore, the starting position of the first target window is A2, and the time corresponding to A2 is the target sampling delay.

[0089] In this embodiment, the initial target sampling delay is obtained by sliding window detection, and the initial target sampling delay is the sampling delay required for demodulating the spectrum.

[0090] Step S3: Determine the error ratio corresponding to the target sampling delay based on the target sampling delay and the optical signal.

[0091] In this step, the initial target sampling delay determined in step S2 is used for sampling to determine the error ratio of the initial target sampling delay during sampling. A higher error ratio indicates more errors occurring with the initial target sampling delay. If the error ratio exceeds a preset value, the initial target sampling delay needs to be adjusted to determine the current target sampling delay, thereby improving the accuracy of the target sampling delay.

[0092] Optionally, step S3 includes steps S31 to S34, as follows:

[0093] Step S31: Taking the rising edge of the first pulse in the optical signal as the starting point, after a target sampling delay, a sub-signal interval of a preset length in the optical signal is collected, and a detection record is recorded.

[0094] Step S32: Calculate the light intensity information in the sub-signal interval.

[0095] Step S33: If the light intensity information does not meet the first condition, record an error.

[0096] Step S34: Calculate the error ratio of the first number to the second number, where the first number is the number of erroneous records and the second number is the number of detected records.

[0097] In this embodiment, the optical signal is sampled according to the target sampling delay. The accuracy of the target sampling delay is determined by the number of errors (the first number) and the number of detections (the second number). This makes it easier to re-determine the target sampling delay when it is inaccurate, thus realizing the automatic adjustment of the target sampling delay.

[0098] Optionally, step S5 is included after step S34, as follows:

[0099] Step S5: If the error ratio is less than or equal to the preset value, take the rising edge of the second pulse in the optical signal as the starting point, after the target sampling delay, collect the sub-signal interval of the preset length in the optical signal, record one detection record, and jump to step S32.

[0100] In this embodiment, if the error ratio is less than or equal to a preset value, it indicates that the accuracy of the initial target sampling delay still meets the requirements, and therefore the initial target sampling delay can continue to be used for sampling and demodulation. Therefore, the second pulse is sampled again according to the initial target sampling delay, and the error ratio is updated according to steps S32 to S34.

[0101] Step S4: If the error ratio is greater than the preset value, adjust the target sampling delay based on sliding window technology and optical signal.

[0102] In this step, if the error ratio is greater than the preset value, it indicates that the initial target sampling delay is no longer applicable, and the target sampling delay needs to be redefined to achieve automatic adjustment of the target sampling delay.

[0103] Optionally, step S4 includes steps S41 to S43, as follows:

[0104] Step S41: Starting from the first target window, slide the sliding window to continue sliding over the optical signal sequence and determine the light intensity information of all optical signal points within the window corresponding to the sliding window.

[0105] Step S42: If the light intensity information meets the first condition, stop sliding the window and determine the window as the second target window.

[0106] Step S43: Determine the starting position of the second target window as the target sampling delay.

[0107] In this embodiment, by continuing to slide the window to determine the current target sampling delay, it is easier to use the new target sampling delay to sample and demodulate the optical signal, thereby improving the accuracy of the target sampling delay.

[0108] For example, combined Figure 6 As shown, Figure 6 In (a), the sliding window 101 is the first target window. Step S41 is to slide the sliding window 101 according to a preset step value (e.g., preset step value = 1) to obtain... Figure 6 The sliding window 102 shown in (b) is a second target window. If the light intensity information of all light signal points in the sliding window 102 satisfies the first condition, then the starting position A2 of the second target window (sliding window 102) is the target sampling delay.

[0109] Optionally, after step S4, step S6 is also included, as follows:

[0110] Step S6, proceed to step S3.

[0111] In this embodiment, after obtaining the current target sampling delay, the current target sampling delay is detected again according to steps S3 and S4. If the error ratio of the current target sampling delay is greater than the preset value again, that is, if the current target sampling delay cannot meet the accuracy requirements, then the target sampling delay needs to be adjusted again to achieve automatic adjustment of the target sampling delay.

[0112] The automatic adjustment method for sampling delay of time-division multiplexed fiber optic hydrophone arrays provided in this application can determine the target sampling delay based on the optical signal output by the time-division multiplexed fiber optic hydrophone array. If numerous errors occur when sampling using the target sampling delay, the method can automatically adjust the target sampling delay based on the optical signal output by the time-division multiplexed fiber optic hydrophone array, achieving automated adjustment of the target sampling delay. This allows for real-time and accurate measurement and automatic correction of the sampling delay of the time-division multiplexed fiber optic hydrophone array during operation, ensuring the long-term stable operation of the automatic adjustment system. It not only enables unattended measurement and automatic control of time-division pulse sampling delay but also improves the autonomous operation capability of the automatic adjustment system for sampling delay of time-division multiplexed fiber optic hydrophone arrays under different array states, enhancing the system's automation level.

[0113] Figure 7 The second flowchart is provided for the automatic adjustment method of sampling delay of time-division multiplexing fiber optic hydrophone array provided in the embodiments of this application.

[0114] Specifically, in combination Figure 7 As shown, the automatic adjustment method for sampling delay of time-division multiplexed fiber optic hydrophone array includes steps S01 to S04, as detailed below:

[0115] Step S01: The signal acquisition module 7 samples the interference light output by the fiber optic hydrophone array to obtain an optical signal sequence.

[0116] In this step, the photoelectric conversion module 6 is used to convert the interference light output by the time-division multiplexed fiber optic hydrophone array into an electrical signal, and then the signal acquisition module 7 is used to convert the electrical signal into a digital signal.

[0117] Step S02: Use a sliding window to detect the optical signal sequence and determine the target sampling delay.

[0118] Specifically, the process of implementing step S02 is the same as step S2 described above, and will not be repeated here.

[0119] Step S03: Sample the optical signal sequence based on the target sampling delay, and record the number of samplings and the number of errors.

[0120] Specifically, the process of implementing step S03 is the same as step S3 described above, and will not be repeated here.

[0121] Step S04: Determine whether the error ratio is greater than the preset value.

[0122] In this step, if the error ratio is greater than a preset value, proceed to step S02 to readjust and determine the target sampling delay. If the error ratio is less than or equal to the preset value, proceed to step S03 to continue sampling using the target sampling delay.

[0123] Corresponding to the aforementioned embodiment of the automatic sampling delay adjustment method for time-division multiplexing fiber optic hydrophone arrays, this application also provides an embodiment of an automatic sampling delay adjustment device for time-division multiplexing fiber optic hydrophone arrays. This automatic sampling delay adjustment system for time-division multiplexing fiber optic hydrophone arrays includes: a laser module, a time-division multiplexing fiber optic hydrophone array, and a delay detection module. The laser module is configured to output a laser signal to the time-division multiplexing fiber optic hydrophone array according to the basic operating parameters of the time-division multiplexing fiber optic hydrophone array. The time-division multiplexing fiber optic hydrophone array is configured to receive the output laser signal and output an optical signal. The delay detection module is configured as follows: S1: Acquire the optical signal output by the time-division multiplexed fiber optic hydrophone array; S2: Determine the target sampling delay based on sliding window technology and the optical signal. The target sampling delay is the difference between the time when the time-division multiplexed fiber optic hydrophone array receives the optical pulse and the time when it samples the output optical signal; S3: Determine the error ratio corresponding to the target sampling delay based on the target sampling delay and the optical signal; S4: If the error ratio is greater than a preset value, adjust the target sampling delay based on sliding window technology and the optical signal.

[0124] The automatic adjustment method for sampling delay of time-division multiplexed fiber optic hydrophone arrays provided in this application can acquire the optical signal output by the time-division multiplexed fiber optic hydrophone array based on the delay detection module, and then determine the target sampling delay based on the optical signal output by the time-division multiplexed fiber optic hydrophone array. If many errors occur when sampling using the target sampling delay, the target sampling delay can be automatically adjusted according to the optical signal output by the time-division multiplexed fiber optic hydrophone array, realizing automated adjustment of the target sampling delay. This allows for real-time and accurate measurement and automatic correction of the sampling delay of the time-division multiplexed fiber optic hydrophone array during operation, ensuring the long-term stable operation of the automatic adjustment system for sampling delay. It not only enables unattended measurement and automatic control of time-division pulse sampling delay, but also improves the autonomous operation capability of the automatic adjustment system for sampling delay of time-division multiplexed fiber optic hydrophone arrays under different array states, enhancing the system's automation level.

[0125] It should be noted that those skilled in the art, upon considering the specification and practicing the application disclosed herein, will readily conceive of other embodiments of this application. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope of this application is indicated by the claims.

[0126] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for automatically adjusting the sampling delay of a time-division multiplexed fiber optic hydrophone array, characterized in that, include: S1: Acquire the optical signal output by the time-division multiplexed fiber optic hydrophone array; S2: Based on the sliding window technology and the optical signal, determine the target sampling delay, which is the difference between the time when the time-division multiplexed fiber optic hydrophone array receives the optical pulse and the time when it samples the output optical signal; S3: Determine the error ratio corresponding to the target sampling delay based on the target sampling delay and the optical signal; S4: If the error ratio is greater than a preset value, adjust the target sampling delay based on the sliding window technology and the optical signal; The optical signal includes an optical signal sequence composed of multiple optical signal points; The determination of the target sampling delay based on the sliding window technique and the optical signal includes: Based on sliding window detection, a first target window is determined; the first target window is defined as the window where the light intensity information of all light signal points within the sliding window satisfies a first condition. The starting position of the first target window is used as the target sampling delay; The step of determining the first target window based on sliding window detection includes: Starting from the initial position of the optical signal sequence, the sliding window slides across the optical signal sequence, and the light intensity information of all optical signal points within the window corresponding to the sliding window is determined; the length of the sliding window is a preset length, which is less than the total number of optical signal points in the optical signal sequence; the step value of the sliding window is a preset step value. If the light intensity information meets the first condition, stop sliding the window and determine the window as the first target window.

2. The automatic adjustment method for sampling delay of time-division multiplexed fiber optic hydrophone array according to claim 1, characterized in that, The light intensity information includes the average light intensity and variance of all light signal points within the sliding window, and the first condition is that the average light intensity is less than a first average light intensity and the variance is less than a first variance.

3. The automatic adjustment method for sampling delay of time-division multiplexed fiber optic hydrophone array according to claim 1, characterized in that, After sliding the sliding window across the optical signal sequence from its initial position and determining the light intensity information of all optical signal points within the window corresponding to the sliding window, the method further includes: If the light intensity information does not meet the first condition, determine whether the sliding window contains the last light signal point of the light signal sequence; If the sliding window contains the last optical signal point of the optical signal sequence, proceed to step S1; If the sliding window does not contain the last optical signal point of the optical signal sequence, the sliding window is slid according to the preset step value, and the light intensity information of all optical signal points within the window of the sliding window is calculated.

4. The automatic adjustment method for sampling delay of time-division multiplexed fiber optic hydrophone array according to claim 1, characterized in that, The step of determining the error ratio corresponding to the target sampling delay based on the target sampling delay and the optical signal includes: S31: Taking the rising edge of the first pulse in the optical signal as the starting point, after the target sampling delay, collect the sub-signal interval of the preset length in the optical signal and record one detection record; S32: Calculate the light intensity information in the sub-signal interval; S33: If the light intensity information does not meet the first condition, record an error record; S34: Calculate the error ratio of the first number to the second number, where the first number is the number of erroneous records and the second number is the number of detected records.

5. The automatic adjustment method for sampling delay of time-division multiplexed fiber optic hydrophone array according to claim 1, characterized in that, When the error ratio is greater than a preset value, adjusting the target sampling delay based on the sliding window technique and the optical signal includes: Starting from the first target window, slide the sliding window to continue sliding over the optical signal sequence, and determine the light intensity information of all optical signal points within the window corresponding to the sliding window; If the light intensity information satisfies the first condition, stop sliding the window and determine the window as the second target window; The starting position of the second target window is determined as the target sampling delay.

6. The automatic adjustment method for sampling delay of time-division multiplexed fiber optic hydrophone array according to claim 4, characterized in that, After determining the error ratio corresponding to the target sampling delay based on the target sampling delay and the optical signal, the method further includes: If the error ratio is less than or equal to a preset value, the rising edge of the second pulse in the optical signal is taken as the starting point. After the target sampling delay, the sub-signal interval of the preset length in the optical signal is collected and the detection record is recorded once. Then, the process jumps to step S32.

7. The automatic adjustment method for sampling delay of time-division multiplexed fiber optic hydrophone array according to claim 1, characterized in that, When the error ratio is greater than a preset value, after adjusting the target sampling delay based on the sliding window technique and the optical signal, the method further includes: Proceed to step S3.

8. A time-division multiplexing fiber optic hydrophone array sampling delay automatic adjustment system, characterized in that, include: The laser module is configured to output a laser signal to the time-division multiplexed fiber optic hydrophone array according to the basic operating parameters of the time-division multiplexed fiber optic hydrophone array. The time-division multiplexed fiber optic hydrophone array is configured to receive the output laser signal and output an optical signal; The delay detection module is configured as follows: S1: acquire the optical signal output by the time-division multiplexed fiber optic hydrophone array; S2: Based on the sliding window technology and the optical signal, determine the target sampling delay, which is the difference between the time when the time-division multiplexed fiber optic hydrophone array receives the optical pulse and the time when it samples the output optical signal; S3: Determine the error ratio corresponding to the target sampling delay based on the target sampling delay and the optical signal; S4: If the error ratio is greater than a preset value, adjust the target sampling delay based on the sliding window technology and the optical signal; The optical signal includes an optical signal sequence composed of multiple optical signal points; The determination of the target sampling delay based on sliding window technology and the optical signal includes: determining a first target window based on sliding window detection; the first target window is defined as the window where the light intensity information of all optical signal points satisfies a first condition; the starting position of the first target window is taken as the target sampling delay; the determination of the first target window based on sliding window detection includes: sliding the sliding window across the optical signal sequence from the initial position of the optical signal sequence, and determining the light intensity information of all optical signal points within the window corresponding to the sliding window; the length of the sliding window is a preset length, which is less than the total number of optical signal points in the optical signal sequence; the step value of the sliding window is a preset step value; when the light intensity information satisfies the first condition, the sliding window is stopped, and the sliding window is determined to be the first target window.

Images