Water body scattering in-situ measurement method and device based on multidirectional data synchronization

Abstract

The invention discloses a water body scattering in-situ measurement method and device based on multidirectional data synchronization, and the method comprises the steps: obtaining corresponding signals of a reference channel and a plurality of collection channels through a data collection module, and enabling the plurality of collection channels to respectively correspond to water body measurement regions in different directions around an underwater robot; collected signals are sent to a processing unit after being subjected to automatic gain control and high-speed analog-to-digital conversion, the back scattering intensity of water body particles at different distances and in different directions is obtained, the back scattering intensity is synchronized with time, position and depth information of an underwater robot, and all-directional full-time monitoring of the water body scattering characteristics is achieved. Meanwhile, on the basis of a homologous sampling clock and unified triggering, an initial delay reference of each acquisition channel relative to a reference channel is obtained through a common calibration pulse, and the initial delay reference is processed based on a time alignment method of a narrowband pilot signal; therefore, sub-sampling-level time synchronization of multi-channel sampling data is realized under a long-term operation condition.

Description

Technical Field

[0001] This invention belongs to the field of scattering measurement technology, specifically relating to an in-situ measurement method and device for water scattering based on multi-directional data synchronization. Background Technology

[0002] Backscattering characteristics of suspended particulate matter in water are important optical parameters characterizing water turbidity, particulate matter concentration, and particle size distribution, playing a significant role in water environment monitoring, water color remote sensing inversion, and marine ecological research. Traditional water scattering measurement methods, including spaceborne, shipborne, and UAV-borne methods, generally only cover the upper water layer and cannot achieve in-situ detection of the entire underwater space. To meet the needs of refined measurement, there is an urgent need to develop mobile detection platforms with flexible deployment capabilities. With the development and expanding application of underwater robot technology, integrating optical measurement devices into underwater robot platforms, and fully utilizing the mobility of underwater robots to compensate for the shortcomings of single-point, single-time in-situ measurement, has become an important way to improve the spatial coverage and automation level of underwater measurement. However, existing underwater robots equipped with optical sensors are mostly used for simple parameter measurements such as turbidity and fluorescence, and rarely design dedicated optical paths and data processing methods for multi-directional backscattering of water, lacking an integrated system solution that simultaneously takes into account high temporal resolution acquisition, distance resolution, and azimuth resolution. This invention designs a seawater scattering measurement system suitable for underwater mobile detection, which has the ability to autonomously, dynamically and continuously detect different profiles of seawater optical parameters. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies, such as limited measurement range, single direction, easy sample degradation, and insufficient spatiotemporal synchronization capability. It provides a method and device for in-situ measurement of water body scattering based on multi-directional data synchronization, which realizes multi-directional, distance-resolved in-situ measurement of backscattering in the area directly below and to the left and right of the water body, and synchronizes it with time, spatial location and depth information to form high-dimensional scattering matrix data, providing a reliable data foundation for water environment monitoring and scientific research.

[0004] In a first aspect, the present invention provides an in-situ measurement method for water body scattering based on multi-directional data synchronization, the method comprising: Simultaneously, multi-directional laser beams are emitted into the water area being measured, and a unidirectional laser beam is emitted outside the water area being measured. The laser signals after backscattering from the multi-directional beams and the corresponding laser signals from the unidirectional beams are collected respectively, and the collected optical signals are converted into data sequences. Among them, the data sequence obtained from the multi-directional beams is the data sequence corresponding to the acquisition channel; the data sequence obtained from the unidirectional beams is the data sequence corresponding to the reference channel. The data sequences of the reference channel and the acquisition channel are aligned using time synchronization. The time synchronization method is as follows: a common calibration pulse is introduced, and the corresponding calibration waveforms of the acquisition channel and the reference channel are obtained under the common calibration pulse; a calibration threshold is set, and the threshold points corresponding to the calibration thresholds in the calibration waveforms of the acquisition channel and the reference channel are obtained respectively; the initial relative delay is obtained by comparing the threshold points corresponding to the reference channel and the acquisition channel; the initial relative delay is processed using a time alignment method based on narrowband pilot signals, and the sampling points in the data sequences of the acquisition channel under different measurement periods are offset based on the processing results. The scattering intensity of the measured water body in the corresponding direction is obtained by using the data sequence of each acquisition channel.

[0005] Preferably, the method for obtaining the initial relative delay is as follows: the arrival time of the calibration pulse is obtained based on the threshold points corresponding to the reference channel and the acquisition channel; the difference between the arrival time of the calibration pulse of each acquisition channel and the reference channel is used as the initial relative delay of each acquisition channel.

[0006] As a preferred method, the initial relative delay is to process the first... The phase change of the pilot phase in each measurement cycle relative to the initial phase difference is mapped to time domain compensation and added to the initial relative delay to obtain the processing result of the initial relative delay.

[0007] Preferably, the pilot phase is obtained by synchronously orthogonally demodulating the data sequences of each channel; the initial phase difference is the difference between the initial pilot phases of the reference channel and the acquisition channel in the initial measurement period.

[0008] As a preferred method, after acquiring the data sequences of each acquisition channel, data diagnostics are performed on the data sequences of each channel. The diagnostic method is as follows: The data sequence of the reference channel is integrated to obtain the test pulse energy indicator; the energy indicator of the test optical path is statistically analyzed to obtain its mean and fluctuation level to construct an energy stability index; if the energy indicator or stability index of the test optical path exceeds the preset threshold, the current measurement cycle is determined to be in an abnormal state.

[0009] As a preferred method, the data sequences of each acquisition channel are subjected to multi-stage digital filtering before obtaining the scattering intensity. The specific process is as follows: The peak detection algorithm is used to identify the peak values ​​representing laser pulses in the voltage waveform of the data sequence. Then, a low-pass filter is used to remove high-frequency mechanical and electromagnetic noise, and a median filter is used to process random noise. Finally, a band-pass filter is used to optimize the useful frequency components in the data sequence.

[0010] Preferably, the process of converting the optical signal into a data sequence is as follows: the optical signals corresponding to the multi-directional beam and the single-directional beam are converted into electrical signals respectively, and the electrical signals are subjected to automatic gain control; after automatic gain control, the amplified electrical signals are subjected to analog-to-digital conversion to obtain the test data sequence.

[0011] Secondly, the present invention provides an in-situ water scattering measurement device based on multi-directional data synchronization, which is used to perform the above-mentioned in-situ water scattering measurement method; the in-situ water scattering measurement device includes an underwater robot and a water scattering measurement device mounted on the underwater robot; the scattering measurement device includes a measurement box and a signal acquisition module and a signal processing module fixed in the measurement box; the signal acquisition module is used to acquire optical signals corresponding to a reference channel and multiple acquisition channels, and convert the optical signals into electrical signals and input them to the signal processing module; the signal processing module is used to convert the electrical signals corresponding to the acquisition channels into digital signals, align the digital signals corresponding to each acquisition channel, and obtain the water scattering intensity of the measured water area based on the aligned digital signals.

[0012] Preferably, the signal acquisition module includes a common optical path, a test optical path, and multiple acquisition optical paths. The common optical path includes a laser, a fiber optic collimator, and a beam splitter. The laser provides the light source required for measurement. The fiber optic collimator collimates the laser beam into parallel light. The beam splitter splits the collimated parallel laser beam into multiple laser beams that enter the measurement area and one laser beam that enters the test optical path. The acquisition optical paths converge the backscattered light generated in different directions from the measurement area. Both the test and acquisition optical paths include lenses and photomultiplier tubes. The lenses focus the optical signal onto the photomultiplier tube. The photomultiplier tube converts the received optical signal into an electrical signal and inputs it to the signal processing module.

[0013] Preferably, the plurality of acquisition optical paths include a left acquisition optical path, a right acquisition optical path, and a vertical acquisition optical path, which are used to measure the scattering intensity of the three water areas on the left, right, and bottom sides of the underwater robot's forward direction, respectively.

[0014] Compared with the existing technology, the beneficial effects of this invention are: 1. Based on the same sampling clock and unified trigger, this invention obtains the initial delay reference of each channel relative to the reference channel through a common calibration pulse, and superimposes the same narrowband pilot signal in each acquisition channel. The sampling data of each channel is aligned in real time by the time compensation amount mapped by the phase change amount, thereby achieving subsampling level time synchronization of multi-channel sampling data under long-term operating conditions.

[0015] 2. In addition to acquiring the data sequence corresponding to the acquisition optical path, this invention also introduces a test optical path. The test optical path is not only used to provide the time zero point and light intensity reference of the laser emission moment, but also used to build a self-diagnostic mechanism for the monitoring system status. This enables real-time monitoring of the laser output status, the transmission status of the common optical path, and the consistency of each acquisition channel, thereby avoiding the influence of abnormal pulses on the backscattering measurement results. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the system structure of Embodiment 1 of the present invention.

[0017] Figure 2 This is a schematic diagram of the measuring device in Embodiment 1 of the present invention.

[0018] Figure 3 This is a schematic diagram of the signal acquisition module in Embodiment 1 of the present invention.

[0019] Figure 4 This is an overall flowchart of Embodiment 2 of the present invention.

[0020] Figure 5 This is a block diagram of the signal processing circuit in Embodiment 2 of the present invention.

[0021] Figure 6 This is a schematic diagram of the scattering value data matrix in Embodiment 2 of the present invention.

[0022] Reference numerals: 1. Laser; 2. Fiber optic collimator; 3. Beam splitter; 4. Lens; 5. Photomultiplier tube; 6. Water area being measured. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] Example 1 like Figure 1 and Figure 2 As shown, an in-situ water scattering measurement device based on multi-directional data synchronization includes an underwater robot and a scattering measurement device mounted on the underwater robot. The scattering measurement device includes a measurement box and a signal acquisition module and a signal processing module fixed inside the measurement box. The measurement box includes a cover for fixing to the underwater robot and a housing for storing the signal acquisition module and the signal processing module. A sealed connection between the cover and the housing prevents water ingress into the signal acquisition module and signal processing module, thus avoiding poor measurement results. The bottom surface and two opposite sides of the housing are provided with exit windows and entrance windows.

[0025] like Figure 3As shown, the signal acquisition module includes a common optical path, a test optical path, and three directional acquisition optical paths. The common optical path includes a laser 1, a fiber optic collimator 2, and a beam splitter 3; the laser 1 provides the light source required for measurement; the fiber optic collimator 2 collimates the beam emitted by the laser 1 into parallel light; the beam splitter 3 splits the collimated parallel laser into four lasers of equal intensity but different directions, which are then directed into the measured water area 6 and the test optical path. The three directional acquisition optical paths are the left-hand acquisition optical path, the right-hand acquisition optical path, and the vertical acquisition optical path; the three directional acquisition optical paths converge the measured water area 6 through the incident window to generate backscattered light in different directions. Both the test optical path and the acquisition optical path include a lens 4 and a photomultiplier tube 5; the lens 4 focuses the optical signal onto the photomultiplier tube 5; the photomultiplier tube 5 converts the received optical signal into an electrical signal and inputs it to the signal processing module.

[0026] In this embodiment, laser 1 is an Nd:YAG solid-state laser with a wavelength of 532±1nm, a pulse width of 5ns, a single pulse energy of 1mJ, and a repetition frequency of 10 Hz.

[0027] The signal processing module includes an automatic gain control module, an analog-to-digital converter (ADC) module, and a processing unit. The automatic gain control module automatically adjusts the gain of the output electrical signals from each photomultiplier tube 5. The ADC module performs analog-to-digital conversion at a sampling frequency of 500 MHz to obtain the corresponding digital sequence. The processing unit performs data buffering, time alignment, digital filtering, distance conversion, and scattering intensity calculation.

[0028] Example 2 like Figure 4 As shown, an in-situ measurement method for water scattering based on multi-directional data synchronization is presented, employing the in-situ water scattering measurement device described in Example 1. This in-situ water scattering measurement method includes the following steps: Step 1: Data Collection like Figure 5 As shown, a laser pulse is emitted by laser 1 and directed into the water area and the test optical path in different directions via beam splitter 3. The laser beams entering the water area are backscattered and converged into the corresponding acquisition optical paths. The converged optical signals are converted into electrical signals by photomultiplier tubes 5 in both the test and acquisition optical paths. Automatic gain control (AGC) is applied to the electrical signals acquired by the test and acquisition optical paths, adjusting the gain based on the real-time signal amplitude. The amplified signals are then subjected to high-speed analog-to-digital conversion (AD) to obtain digital sequences for three acquisition channels and one reference channel. The digital sequences corresponding to each channel are then sent to the processing unit (CPU).

[0029] The processing unit uses the same trigger signal as laser 1 to acquire the digital sequences of each channel, ensuring that each channel simultaneously acquires a fixed-length sampling window under the same trigger edge. After all four channels have completed one trigger acquisition, the digital sequences of the four channels are recorded to construct a frame sequence. , can be represented as: in For the first The start timestamp of each measurement cycle (trigger count). ; For the first The count value corresponding to each measurement cycle; The clock frequency of the processing unit's timer; The sampling frequency; The discrete data sequence corresponding to the reference channel; This refers to the discrete data sequence corresponding to the acquisition channel.

[0030] Step 2: Unify the timeline Unify the time axis of each discrete data sequence and obtain each sampling point of the discrete data sequence. n physical time Its expression is: in, ; This represents the number of sampling points in the discrete data sequence.

[0031] Step 3: Obtain the initial relative delay All channels are connected to the same common calibration pulse, and the calibration waveforms of the three acquisition channels are acquired under the same trigger. , , and reference channel calibration waveform And by setting calibration thresholds Obtain each channel in a certain way i Cross-threshold point ,Right now , Based on the threshold point Interpolate the calibration waveform to obtain the calibration threshold. Corresponding threshold point , can be represented as: Based on the threshold points of each channel Obtain the arrival time of each calibration pulse. Its expression is: The initial relative delay of each acquisition channel is obtained by subtracting the arrival time of the calibration pulse of the reference channel from the arrival time of the calibration pulse of each acquisition channel. , can be represented as: Step 4: Time Alignment To further compensate for the slight changes in channel delay caused by temperature variations and analog link characteristic drift during long-term system operation, an online continuous-time alignment method based on narrowband pilot signals is introduced to process the initial relative delay. The specific process is as follows: A pilot injection node is set between the automatic gain control module and the analog-to-digital conversion module. Narrowband pilot signals generated by the same reference clock are simultaneously superimposed and injected into the analog signals of each channel. The pilot frequency is outside the main energy bandwidth of the scattered echo, and its amplitude is lower than the effective echo signal, thus not affecting normal measurements. The sampled signal of each channel is represented as: in, To superimpose the pilot signal, the first The discrete data sequence corresponding to each channel; For the first The original discrete data sequence corresponding to each channel; Pilot amplitude; The pilot frequency; For the first Pilot phase of each measurement cycle.

[0032] Pilot phase The method to obtain it is as follows: (1) Initial state after calibration pulse alignment is completed In this case, the digital sequences acquired from each channel are synchronously orthogonally demodulated within a sliding time window to extract the initial pilot phase of the pilot signal. Its expression is: in, Indicates the pilot signal at the 1st Initial orthogonal components in each channel; Indicates the pilot signal at the 1st The initial in-phase components in each channel; a These are preset coefficients.

[0033] (2) Construct the initial phase difference based on the initial pilot phases corresponding to the reference channel and the acquisition channel. Used to record the phase reference and determine the mapping starting point, it can be represented as: (3) Extracting the pilot signal at the 1st Pilot phase of each measurement cycle Its expression is: in, Indicates the pilot signal at the 1st The first channel, the first Orthogonal components in the period, Indicates the pilot signal at the 1st The first channel, the first In-phase components within a period.

[0034] (4) with the first Pilot phase of each measurement cycle The phase change relative to the initial state is taken as the incremental drift of the channel delay, and this incremental drift is accurately mapped to time domain compensation to obtain the time domain compensation of each acquisition channel in the first phase. Relative time delay within the next measurement period Its expression is: (5) Delay the relative time Mapped to sampling point offset And based on the sampling point offset The integer and fractional parts of the discrete data sequence Integer shifting and fractional linear interpolation are implemented to achieve time alignment across multiple acquisition channels. Sampling point offset. Represented as: Step 5: Data Collection and Diagnosis 5-1. Within each laser-triggered measurement cycle, first identify the arrival time of the laser pulse in the reference channel and extract a valid sampling window containing the test pulse. Integrate the reference channel sampling signal within this window to obtain the... Test pulse energy indication for each measurement cycle This is used to characterize the single-pulse output and common optical path transmission state of the laser; its acquisition method is as follows: in, Indicates the first In the measurement cycle, the test optical path is at the... The amplitude of each sampling point; and To cover the integration window boundary of the main energy of the test pulse.

[0035] 5-2. For each acquisition channel, integrate the backscattered signal within the effective echo time window to obtain the original scattering intensity indication. and using energy indicators For the original scattering intensity indication Normalization is performed to obtain the normalized scattering intensity. Its expression is: in, It is a constant that prevents division by zero.

[0036] This normalization process can eliminate the influence of laser pulse energy fluctuations, splitting ratio changes, and slow gain drift of the photodetector on the measurement results.

[0037] 5-3. Over multiple consecutive measurement periods, perform sliding statistics on the energy indication of the test optical path, calculate its mean and fluctuation level, and construct an energy stability index. The stability of laser output and common optical path transmission is characterized by the following method: in, To test the sliding average of the pulse energy indication; This is the standard deviation of the pulse energy indicator. This indicator is used to characterize the stability of laser output and common optical path transmission.

[0038] 5-4. When testing the energy indicator of the optical path or stability index When the threshold is exceeded, the current measurement cycle is determined to be in an abnormal state, and a corresponding health flag is generated. Measurement data in an abnormal state can be marked as invalid data or used to trigger a resampling operation, thereby avoiding the influence of abnormal pulses on backscatter measurement results.

[0039] Step Six: Multi-stage Digital Filtering Multi-level digital filtering is applied to the discrete data sequences of each acquisition channel. The specific process is as follows: First, a peak detection algorithm (threshold determination) is used to identify the peak values ​​representing laser pulses in the voltage waveform of the discrete data sequence. The selected peak values ​​should conform to the laser's pulse width (5 ns) and repetition frequency (10 Hz). Then, a low-pass filter is used to remove high-frequency mechanical and electromagnetic noise, and a median filter is used to process random noise. Finally, a band-pass filter is used to optimize the useful frequency components of the discrete data sequence, minimizing the impact of noise without losing important data.

[0040] Step 7: Obtain the scattering intensity Using sampling frequency The speed of light in water is used to number the sampling points in the discrete data sequence of each acquisition channel. Convert to corresponding optical path distance The method to obtain it is as follows: in, v Let be the speed at which light travels in water. ; The speed of light in a vacuum; The refractive index of water.

[0041] The voltage value detected by the photomultiplier tube was calibrated through experiments. Converted to light intensity It is represented as: in, is the conversion factor of the photomultiplier tube.

[0042] Based on Mie scattering theory, a model is established by relating the backscattered light intensity to the radius, refractive index, and particle size distribution parameters of particles in the water. Further inversion of other particle parameters can be performed as needed. The specific calculation formula is as follows: in, The scattering angle; The wavelength of the laser; Let be the radius of the water particle; The relative refractive index of the water particles; Indicates wave number; and These are coefficients obtained through Mie scattering theory; It is a Legendre polynomial.

[0043] To reduce the impact of laser pulse width on temporal resolution, the scattering intensity is averaged within the sampling point range corresponding to the pulse width to obtain the average scattering intensity of a single pulse. Its expression is: in, The measurement period; The scattering intensity is denoted as .

[0044] Test points were selected at intervals of 0.5m, and the calculated scattering intensity was... Along with the corresponding GPS location, depth value, and timestamp, the data is stored as a complete data record in the scattering matrix for subsequent analysis. The scattering matrix data format is as follows: ;in, Indicates time ,Location and depth The light scattering intensity of water particles, such as Figure 6 As shown.

[0045] This invention proposes an in-situ measurement method and device for water scattering based on multi-directional data synchronization. It supports underwater mobile detection in different water scenarios and can autonomously, dynamically, and continuously acquire water optical parameters from different profiles, solving the problem that traditional methods such as spaceborne, shipborne, and airborne methods cannot cover the entire detection area.

Claims

1. A method for in-situ measurement of water scattering based on multi-directional data synchronization, characterized in that: The method includes: Simultaneously, multi-directional laser beams are emitted into the water area being measured, and a unidirectional laser beam is emitted outside the water area being measured. The laser signals after backscattering from the multi-directional laser beams and the corresponding laser signals from the unidirectional laser beams are collected respectively, and the collected scattered signals are converted into data sequences. Among them, the data sequence obtained from the multi-directional laser beams is the data sequence corresponding to the acquisition channel; the data sequence obtained from the unidirectional laser beams is the data sequence corresponding to the reference channel. The data sequences of the reference channel and the acquisition channel are aligned using time synchronization. The time synchronization method is as follows: a common calibration pulse is introduced, and the corresponding calibration waveforms of the acquisition channel and the reference channel are obtained under the common calibration pulse; a calibration threshold is set, and the threshold points corresponding to the calibration thresholds in the calibration waveforms of the acquisition channel and the reference channel are obtained respectively; the initial relative delay is obtained by comparing the threshold points corresponding to the reference channel and the acquisition channel; the initial relative delay is processed using a time alignment method based on narrowband pilot signals, and the sampling points in the data sequences of the acquisition channel under different measurement periods are offset based on the processing results. The scattering intensity of the measured water body in the corresponding direction is obtained by using the data sequence of each acquisition channel.

2. The in-situ measurement method for water scattering based on multi-directional data synchronization according to claim 1, characterized in that: The method for obtaining the initial relative delay is as follows: the arrival time of the calibration pulse is obtained based on the threshold points corresponding to the reference channel and the acquisition channel; the difference between the arrival time of the calibration pulse of each acquisition channel and the reference channel is used as the initial relative delay of each acquisition channel.

3. The in-situ measurement method for water scattering based on multi-directional data synchronization according to claim 1, characterized in that: The method for processing the initial relative delay is as follows: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error.] The phase change of the pilot phase in each measurement cycle relative to the initial phase difference is mapped to time domain compensation and added to the initial relative delay to obtain the processing result of the initial relative delay.

4. The in-situ measurement method for water scattering based on multi-directional data synchronization according to claim 3, characterized in that: The pilot phase is obtained by synchronously orthogonally demodulating the data sequences of each channel; the initial phase difference is the difference between the initial pilot phases of the reference channel and the acquisition channel in the initial measurement period.

5. The in-situ measurement method for water scattering based on multi-directional data synchronization according to claim 1, characterized in that: After acquiring the data sequences from each acquisition channel, data diagnostics are performed on the data sequences of each channel. The diagnostic methods are as follows: Integrate the data sequence of the reference channel to obtain the test pulse energy indication; A sliding statistical analysis was performed on the energy indication of the test optical path to obtain its mean and fluctuation level, thereby constructing an energy stability index. If the energy indication or stability index of the test optical path exceeds the preset threshold, the current measurement cycle is determined to be in an abnormal state.

6. The in-situ measurement method for water scattering based on multi-directional data synchronization according to claim 1, characterized in that: Before acquiring the scattering intensity, the data sequences from each acquisition channel undergo multi-stage digital filtering. The specific process is as follows: The peak detection algorithm is used to identify the peak values ​​representing laser pulses in the voltage waveform of the data sequence. Then, a low-pass filter is used to remove high-frequency mechanical and electromagnetic noise, and a median filter is used to process random noise. Finally, a band-pass filter is used to optimize the useful frequency components in the data sequence.

7. The in-situ measurement method for water scattering based on multi-directional data synchronization according to claim 1, characterized in that: The process of converting the laser signal into a data sequence is as follows: the laser signals corresponding to the multi-directional laser beam and the single-directional laser beam are converted into electrical signals respectively, and the electrical signals are subjected to automatic gain control; after automatic gain control, the amplified electrical signals are subjected to analog-to-digital conversion to obtain the data sequence.

8. A water scattering in-situ measurement device based on multi-directional data synchronization, characterized in that: The method for performing in-situ water scattering measurement based on multi-directional data synchronization as described in claim 1; the in-situ water scattering measurement device includes an underwater robot and a scattering measurement device mounted on the underwater robot; the scattering measurement device includes a measurement box and a signal acquisition module and a signal processing module fixed in the measurement box; the signal acquisition module is used to acquire the optical signals corresponding to the reference channel and multiple acquisition channels, and converts the laser signal into an electrical signal before inputting it to the signal processing module. The signal processing module is used to convert the electrical signals corresponding to the acquisition channels into digital signals, align the digital signals corresponding to each acquisition channel, and obtain the scattering intensity of the water body under test based on the aligned digital signals.

9. The in-situ water scattering measurement device based on multi-directional data synchronization according to claim 8, characterized in that: The signal acquisition module includes a common optical path, a test optical path, and multiple acquisition optical paths. The common optical path includes a laser (1), a fiber collimator (2), and a beam splitter (3). The laser (1) is used to provide the light source required for measurement. The fiber collimator (2) is used to collimate the beam emitted by the laser (1) into parallel light. The beam splitter (3) is used to split the collimated parallel laser into multiple beams that enter the measurement water area (6) and one beam that enters the test optical path. The acquisition optical paths are used to converge the backscattered light generated in different directions by the measurement water area (6). Both the test optical path and the acquisition optical path include a lens (4) and a photomultiplier tube (5). The lens (4) is used to focus the laser signal onto the photomultiplier tube (5). The photomultiplier tube (5) is used to convert the received laser signal into an electrical signal and input it to the signal processing module.

10. The in-situ water scattering measurement device based on multi-directional data synchronization according to claim 9, characterized in that: The multiple acquisition optical paths include a left acquisition optical path, a right acquisition optical path, and a vertical acquisition optical path, which are used to measure the scattering intensity on the left, right, and bottom sides of the underwater robot, respectively.

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