Seabed space-time base station and data processing method

Abstract

The invention discloses a seabed space-time base station and a data processing method, the base station comprises a base, a pressure-resistant cabin, a floating ball and a pedestal, the middle part of the base is provided with a conduction integrated transducer, and four hydrophones are uniformly distributed around the base. The data processing method comprises the following steps: the transducer sends a communication signal to a target carrier and calculates propagation time; calculating clock offset by using signal receiving and transmitting time, calibrating a clock for a reference station, and timing for a target carrier; after time service, calculating the position of the base station by using an acoustic observation equation between the sea surface carrier and the base station and a pressure-water depth observation equation of the base station, and judging the displacement of the base station by using a Bayesian framework; after position calibration, a processing strategy is selected according to the position of the target carrier, and when more than two base station signals are received, the target carrier automatically constructs an observation equation to calculate the position; and when only one base station signal is received, the base station determines a target position according to an ultra-short baseline mode and sends a result. According to the invention, the construction cost of the seabed space-time reference network is reduced, near-far fusion positioning is realized, and the service range and performance are improved.

Description

Technical Field

[0001] This invention relates to the field of positioning technology, specifically to an underwater spatiotemporal reference station and a data processing method. Background Technology

[0002] The abundant natural resources contained in the ocean provide a guarantee for economic development and population growth. Since marine activities cannot be separated from geodetic benchmarks and positioning and navigation technologies, such as seabed resource exploration, underwater vehicle navigation, underwater engineering construction, seabed crust deformation measurement, and continental shelf landslide monitoring, all require high-precision underwater positioning services. Therefore, sensing and utilizing the ocean requires the support of the marine spatiotemporal benchmark network as an infrastructure.

[0003] Currently, the global spatiotemporal reference network is centered on GNSS / BDS, with its surface and near-Earth space components providing services for many years. However, due to severe attenuation of GNSS signals (electromagnetic waves) in seawater, it cannot provide underwater navigation and positioning services. Sound waves can effectively propagate over long distances in seawater. To achieve integrated global air-space-ground-sea navigation and positioning services, a marine spatiotemporal reference network based on acoustic technology is needed to provide three-dimensional positioning, navigation, and timing services within the ocean. A complete marine spatiotemporal reference network includes fixed seabed spatiotemporal reference stations, floating sea surface base stations, and mobile base stations in the water; therefore, seabed spatiotemporal reference stations form the framework of the base station network.

[0004] Currently, seabed geodetic reference stations primarily monitor the displacement of seafloor plates through measurements taken from surface carriers, serving marine disaster monitoring and marine scientific research. However, they are difficult to directly apply to underwater location services. Underwater acoustic positioning technology is a core technology in the construction of marine spatiotemporal reference stations. It retrieves target locations by measuring the time or phase difference between sound pulses propagating along different paths. This technology can be categorized into long baseline, short baseline, and ultra-short baseline positioning technologies based on baseline length. Long baseline positioning technology offers the highest accuracy, obtaining the underwater target's location through distance intersection by measuring the sound signal propagation time, but its accuracy is relatively low. Ultra-short baseline positioning technology is easy to operate, determining the target location through distance-azimuth positioning by measuring propagation time and azimuth angle, but its accuracy is lower.

[0005] In existing technologies, the sound speed profile (SSP) used for ray tracking has spatiotemporal uncertainties, geophysical models (such as tides and sea level anomalies) have residuals, and time-varying sensor errors all affect the positioning and detection of target carriers. Furthermore, existing technologies rarely have underwater time synchronization services, and the methods for calibrating the position of seabed spatiotemporal reference stations do not integrate pressure gauge observation data at the observation level. In addition, existing technologies cannot achieve near-far fusion positioning when providing services for underwater targets, meaning that navigation and positioning services cannot be provided when the acoustic observation data of the reference station is insufficient. Summary of the Invention

[0006] To address the aforementioned shortcomings of existing technologies, this invention provides an underwater spatiotemporal reference station and a data processing method, proposing a novel underwater spatiotemporal reference station design to meet the needs of rapid positioning and navigation using underwater base stations.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A seabed time and space reference station is provided, which includes a seabed base and a support frame placed on the seabed base. The upper end of the support frame is provided with a base and the lower end is provided with a pressure chamber. A communication and conduction integrated transducer is provided in the middle of the base. Four acoustic hydrophones are evenly arranged around the communication and conduction integrated transducer. The four acoustic hydrophones are mounted on the base by L-shaped brackets. A support ring connecting the four L-shaped brackets is provided around the outside of the base.

[0008] Furthermore, at least five seabed spatiotemporal reference stations form a seabed reference network with a square structure. The five seabed spatiotemporal reference stations are distributed at the four vertices and the center of the seabed reference network, and the side length of the seabed reference network is the farthest acoustic action distance of the seabed spatiotemporal reference stations.

[0009] Furthermore, buoys are installed around the pressure tank, and a release device connected to the seabed base is installed at the bottom of the pressure tank.

[0010] A data processing method for the aforementioned seabed spatiotemporal reference station is provided, comprising the following steps: S1: The integrated communication and conduction transducer sends a communication signal to the target carrier through the communication module, and calculates the communication time between the integrated communication and conduction transducer and the target carrier based on the clock information of the communication signal. S2: The integrated communication and navigation transducer immediately sends an acoustic signal to the target carrier, and the target carrier sends a feedback acoustic signal to the integrated communication and navigation transducer. The clock offset is calculated using the reception time and transmission time of the acoustic signal and the feedback acoustic signal. Based on the clock offset, the seabed time and space reference station is clocked, and the target carrier is given a time synchronization service. S3: After the seabed time and space reference station completes the time synchronization service for the target carrier, it uses the acoustic observation equation between the sea surface carrier and the seabed time and space reference station and the pressure-depth observation equation of the seabed time and space reference station to solve the time-based position sequence of the seabed time and space reference station, and determines whether the seabed time and space reference station has been displaced based on the Bayesian framework, and performs reference position calibration for the seabed time and space reference station that has been displaced. S4: After completing the benchmark calibration of the seabed spatiotemporal reference station, locate the underwater target carrier based on its position on the seabed baseline network, and obtain the target carrier's position information; specifically: When the target carrier can receive acoustic signals from at least two seabed spatiotemporal reference stations in the seabed network, the position information of the target carrier can be obtained by constructing acoustic observation equations and pressure-depth observation equations between the two seabed spatiotemporal reference stations and the target carrier. When the target carrier can only receive the acoustic signal from one seabed time-space reference station in the seabed base network, the target carrier is located using the seabed time-space reference station according to the ultra-short baseline acoustic positioning mode, and the location information of the target carrier is sent to the target carrier through the communication module.

[0011] Further, step S1 includes: S11: The integrated communication and conduction transducer sends a communication signal to the target carrier via the communication module. The communication signal carries clock information. After receiving the communication signal, the target carrier immediately sends a feedback communication signal to the integrated communication and conduction transducer. The integrated communication and conduction transducer records the time when it receives the feedback communication signal. t 2; S12: Based on the time information in the communication signal t 1. Calculate the communication time between the integrated communication and conduction transducer and the target carrier. .

[0012] Further, step S2 includes: S21: After receiving the feedback communication signal, the integrated communication transducer immediately sends an acoustic signal to the target carrier and records the acoustic signal transmission time. After the target carrier receives the acoustic signal, it records the time of acoustic signal reception. The target carrier immediately transmits a feedback acoustic signal to the seabed time-space reference station and records the transmission time of the feedback acoustic signal. Four acoustic hydrophones received feedback signals, and the four acoustic hydrophones recorded the reception time of the feedback signals. ; S22: Select four receiving times Outliers in; Calculate the four reception times average ; Calculate the four reception times Compared with the average Compared to the offset rate ; ; in, i This is the serial number for the acoustic hydrophone. For the first i The reception time of the acoustic signal feedback from the acoustic hydrophone; Set the threshold for the offset rate. ,like Then determine the firsti The reception time of the acoustic hydrophone feedback signal If it is an outlier, then determine the first one. i The reception time of the acoustic hydrophone feedback signal This is a normal value; Receiving time Delete outliers and retain the reception time. The normal value, and the retained reception time is calculated. Number of normal values n ,like If the signal is positive, proceed to step S5; otherwise, return to step S3 and the integrated transducer retransmits the acoustic signal to the target carrier. S23: Calculate reception time average of normal values ; S24: Utilizing launch time Reception time Launch time and average Calculate clock offset The seabed time and space reference station is based on the clock offset. To calibrate the clock of the seabed time and space reference station and provide time service to the target carrier; .

[0013] Further, step S3 includes: S31: After the seabed time and space reference station completes the time synchronization service for the target carrier, it uses the spatial three-dimensional coordinates of the sea surface carrier... Constructing the acoustic observation equations for the seabed spatiotemporal reference station: ; in, The spatial three-dimensional coordinates of the seabed spatiotemporal reference station. The round-trip observation propagation time of the sound signal. The spatial trajectory of the sound signal. To vary with depth z The changing speed of the sound signal This is the profile correction amount for the velocity of the sound signal. Based on the historical acoustic signal speed, s To propagate spatial trajectory An infinitesimal arc-length infinitesimal element; Spatial three-dimensional coordinates of sea surface carrier Spatial three-dimensional coordinates of the seabed time and space reference station Connect the lines, establish a local two-dimensional coordinate system within the two-dimensional vertical plane of the connected lines, and determine the spatial trajectory of the sound signal propagation. Satisfy the ray tracking equation: ; in, x The horizontal distance within the local two-dimensional coordinate system. The angle between the tangent of the sound ray in the spatial trajectory of the sound signal and the horizontal direction; S32: Constructing the pressure-depth observation equation between the surface carrier and the seabed spatiotemporal reference station: ; in, The instantaneous water depth is predicted by a pressure sensor at the location of the seabed spatiotemporal reference station. Based on three-dimensional spatial coordinates Transformation function for converting ground altitude. These are the tidal water level, the non-tidal sea level, and the residual water level, respectively. S33: Predicted instantaneous water depth The position vector of the seabed spatiotemporal reference station based on time series is obtained by inputting the acoustic observation equation. ; Obtain the seabed spatiotemporal reference station from time 1 to N Position sequence And based on the Bayesian framework, calculate at each candidate time point The posterior probability of a displacement event occurring at an underwater spatiotemporal reference station; ; in, Let be the likelihood function. Candidate time points Long-term linear motion velocity in the first and second phases Candidate time points The prior probability distribution, Candidate time points The posterior probability of a displacement event occurring at an underwater spatiotemporal reference station; S34: Set the threshold for the posterior probability ,like Then, the candidate time point of the seabed spatiotemporal reference station is determined. If displacement occurs, the reference position of the seabed time-space reference station where displacement occurred is determined; otherwise, no displacement has occurred.

[0014] The beneficial effects of this invention are as follows: It can reduce the construction cost of seabed spatiotemporal reference networks, realize a near-far integrated positioning method, and ensure that the service range of the reference network is maximized under the condition of a fixed number of seabed base stations. Simultaneously, it can ensure that seabed spatiotemporal reference stations provide both location and time services to underwater equipment. It utilizes a communication and navigation integrated transducer to replace the traditional seabed long-baseline positioning transducer for exchanging spatiotemporal location information with the service object (target carrier).

[0015] This invention eliminates systematic errors by estimating sound velocity profile errors and geophysical model residuals as state variables, effectively improving the accuracy of absolute position calculation for seabed reference points. It can not only output the coordinates of the reference station, but also simultaneously provide accurate local sound velocity profile correction fields, online calibration of sensor error parameters, and probability assessment of target carrier displacement events. Attached Figure Description

[0016] Figure 1 This is the front view of the seabed time and space reference station.

[0017] Figure 2 This is a top view of the seabed time and space reference station.

[0018] The components include: 1. base, 2. integrated transducer for communication and conduction, 3. support ring, 4. L-shaped bracket, 5. acoustic hydrophone, 6. seabed base, 7. pressure chamber, 8. buoy, and 9. release device. Detailed Implementation

[0019] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0020] like Figure 1 and Figure 2 As shown, an underwater time and space reference station includes an underwater base 6 and a support frame placed above the underwater base 6. The upper end of the support frame is provided with a base 1 and the lower end is provided with a pressure chamber 7. The base 1 has an integrated communication and conduction transducer 2 in the middle. Four acoustic hydrophones 5 are evenly arranged around the integrated communication and conduction transducer 2. The four acoustic hydrophones 5 are mounted on the base 1 by L-shaped brackets 4. A support ring 3 connecting the four L-shaped brackets 4 is provided around the outside of the base 1.

[0021] In this embodiment, at least five seabed spatiotemporal reference stations form a seabed reference network. The seabed reference network has a square structure, with the five seabed spatiotemporal reference stations distributed at the four vertices and the center of the network. The side length of the seabed reference network is the maximum acoustic signal range of the seabed spatiotemporal reference stations. Buoys 8 are arranged around the pressure chamber 7, and a release device 9 connected to the seabed base is located at the bottom of the pressure chamber 7. The seabed base 6 is released via the release device 9, and the buoyancy of the buoys 8 enables the recovery of the seabed spatiotemporal reference stations.

[0022] Based on the distribution of seabed spatiotemporal reference stations in the seabed network and their acoustic signal coverage, for areas where three or more sets of acoustic signals can be received simultaneously, ranging can be performed based on the acoustic signals broadcast by the seabed spatiotemporal reference stations. Using long baseline positioning technology, positioning and navigation services for the target vehicle can be achieved, with the position result directly calculated online by the target vehicle. This method belongs to high-precision underwater positioning services. For areas where only one set of acoustic signals can be received, the target vehicle adjusts the seabed spatiotemporal reference station to active positioning mode via acoustic communication commands. Then, the seabed spatiotemporal reference station uses ultra-short baseline computational positioning technology to achieve navigation and positioning of the target vehicle and feeds back the position information to the target vehicle via acoustic communication. For areas where two sets of acoustic signals can be received, the target vehicle can comprehensively utilize the acoustic observation equations between itself and the seabed spatiotemporal reference station, as well as the pressure-depth observation equations, to calculate its position online. Alternatively, the seabed reference ultra-short baseline positioning result can be used as an independent acoustic observation equation, combined with the acoustic observation equations of the two long baseline modes to achieve the target vehicle's positioning. Considering that long-baseline underwater acoustic positioning offers high-precision positioning, while ultra-short-baseline positioning has lower accuracy, the location service mode of the seabed spatiotemporal reference station in this invention can be summarized as remote positioning guidance outside the reference network and high-precision positioning and navigation within the reference network. Simultaneously, within the coverage area of ​​each seabed spatiotemporal reference station, time synchronization and timing functions can be achieved through integrated acoustic communication and time information responses.

[0023] A data processing method for the aforementioned seabed spatiotemporal reference station includes the following steps: S1: The integrated communication and conduction transducer 2 sends a communication signal to the target carrier through the communication module, and calculates the communication time between the integrated communication and conduction transducer 2 and the target carrier based on the clock information of the communication signal. Step S1 specifically includes: S11: The integrated communication and conduction transducer 2 sends a communication signal to the target carrier through the communication module. The communication signal carries clock information. After receiving the communication signal, the target carrier immediately sends a feedback communication signal to the integrated communication and conduction transducer 2. The integrated communication and conduction transducer 2 records the time of receiving the feedback communication signal. t 2; S12: Based on the time information in the communication signal t1. Calculate the communication time between the integrated communication and conduction transducer 2 and the target carrier. .

[0024] S2: The integrated communication and navigation transducer 2 immediately sends an acoustic signal to the target carrier, and the target carrier sends a feedback acoustic signal to the integrated communication and navigation transducer 2. The clock offset is calculated using the reception and transmission times of the acoustic signal and the feedback acoustic signal. Based on the clock offset, the seabed time-space reference station is clock-calibrated, and time synchronization services are provided to the target carrier. Step S2 specifically includes: S21: After receiving the feedback communication signal, the integrated communication transducer 2 immediately sends an acoustic signal to the target carrier and records the acoustic signal transmission time. After the target carrier receives the acoustic signal, it records the time of acoustic signal reception. The target carrier immediately transmits a feedback acoustic signal to the seabed time-space reference station and records the transmission time of the feedback acoustic signal. Four acoustic hydrophones 5 received feedback sound signals respectively, and the four acoustic hydrophones 5 recorded the reception time of the feedback sound signals. ; S22: Select four receiving times Outliers in; Calculate the four reception times average ; Calculate the four reception times Compared with the average Compared to the offset rate ; ; in, i This is the serial number for acoustic hydrophone 5. For the first i The reception time of the feedback sound signal of each acoustic hydrophone 5; Set the threshold for the offset rate. ,like Then determine the first i The acoustic hydrophone has a 5-hour feedback signal reception time. If it is an outlier, then determine the first one. i The acoustic hydrophone has a 5-hour feedback signal reception time. This is a normal value; Receiving time Delete outliers and retain the reception time. The normal value, and the retained reception time is calculated. Number of normal values n ,like If the signal is positive, proceed to step S5; otherwise, return to step S3 and the integrated transducer 2 will resend the acoustic signal to the target carrier. S23: Calculate reception time average of normal values ; S24: Utilizing launch time Reception time Launch time and average Calculate clock offset The seabed time and space reference station is based on the clock offset. To calibrate the clock of the seabed time and space reference station and provide time service to the target carrier; .

[0025] S3: After the seabed spatiotemporal reference station completes the time synchronization service for the target carrier, it uses the acoustic observation equations between the surface carrier and the seabed spatiotemporal reference station, as well as the pressure-depth observation equations of the seabed spatiotemporal reference station, to calculate the time-based position sequence of the seabed spatiotemporal reference station. Based on a Bayesian framework, it determines whether the seabed spatiotemporal reference station has shifted, and calibrates the reference position of any shifted seabed spatiotemporal reference stations. Step S3 specifically includes: S31: After the seabed time and space reference station completes the time synchronization service for the target carrier, it uses the spatial three-dimensional coordinates of the sea surface carrier... Constructing the acoustic observation equations for the seabed spatiotemporal reference station: ; in, The spatial three-dimensional coordinates of the target carrier, The round-trip observation propagation time of the sound signal. This represents the spatial trajectory of a sound signal, indicating the actual propagation curve of the sound wave from the target carrier (transmitter / receiver point) to the seabed spatiotemporal reference station (reflection / response point). It is not a straight line, but a curve that is bent due to the change in the speed of sound in seawater with depth. Its shape is determined by Snell's law. To vary with depth z The changing speed of the sound signal This is the profile correction amount for the velocity of the sound signal. Based on the historical acoustic signal speed, s To propagate spatial trajectory An infinitesimal arc-length infinitesimal element; Spatial three-dimensional coordinates of sea surface carrier Spatial three-dimensional coordinates of the seabed time and space reference station Connect the lines, and establish a local two-dimensional coordinate system in the two-dimensional vertical plane of the connecting lines. The spatial trajectory of the sound signal propagation is then defined. Satisfy the ray tracking equation: ; in, x The horizontal distance is the distance between points on the sound ray trajectory within a local two-dimensional coordinate system. The angle between the tangent of the sound ray on the spatial trajectory of the sound signal and the horizontal direction is called the glancing angle, which is known at the emission point (related to the transducer attitude). This represents the vertical gradient of the sound velocity. It is this non-zero gradient that causes the sound ray to bend. When the sound velocity increases with depth (positive gradient), the sound ray bends upward; conversely, it bends downward.

[0026] S32: Constructing the pressure-depth observation equation between the surface carrier and the seabed spatiotemporal reference station: ; in, The instantaneous water depth is predicted by a pressure sensor at the location of the seabed spatiotemporal reference station. Based on three-dimensional spatial coordinates Transformation function for converting ground altitude. These are the tidal water level, the non-tidal sea level, and the residual water level, respectively. S33: Predicted instantaneous water depth The position vector of the seabed spatiotemporal reference station based on time series is obtained by inputting the acoustic observation equation. ; Obtain the seabed spatiotemporal reference station from time 1 to N Position sequence And based on the Bayesian framework, calculate at each candidate time point The posterior probability of a displacement event occurring at an underwater spatiotemporal reference station; ; in, Let be the likelihood function. Candidate time points Long-term linear motion velocity in the first and second phases Candidate time points The prior probability distribution, Candidate time points The posterior probability of a displacement event occurring at an underwater spatiotemporal reference station; S34: Set the threshold for the posterior probability ,like Then, the candidate time point of the seabed spatiotemporal reference station is determined. If displacement occurs, the reference position of the seabed time-space reference station where displacement occurred is determined; otherwise, no displacement has occurred.

[0027] S4: After completing the benchmark calibration of the seabed spatiotemporal reference station, locate the underwater target carrier based on its position on the seabed baseline network, and obtain the target carrier's position information; specifically: When the target carrier can receive acoustic signals from at least two seabed spatiotemporal reference stations in the seabed network, the position information (three-dimensional spatial coordinates) of the target carrier can be obtained by constructing acoustic observation equations and pressure-depth observation equations between the two seabed spatiotemporal reference stations and the target carrier. When the target carrier can only receive the acoustic signal from one seabed time-space reference station in the seabed base network, the target carrier is located using the seabed time-space reference station according to the ultra-short baseline acoustic positioning mode, and the location information of the target carrier is sent to the target carrier through the communication module.

[0028] This invention reduces the construction cost of seabed spatiotemporal reference networks and enables a near-far integrated positioning method, ensuring that the service range of the reference network is maximized within a fixed number of seabed base stations. Simultaneously, it ensures that seabed spatiotemporal reference stations provide both location and time services to underwater equipment. It utilizes a communication and navigation integrated transducer to replace the traditional seabed long-baseline positioning transducer for exchanging spatiotemporal location information with the service object (target carrier).

[0029] This invention eliminates systematic errors by estimating sound velocity profile errors and geophysical model residuals as state variables, effectively improving the accuracy of absolute position calculation for seabed reference points. It can not only output the coordinates of the reference station, but also simultaneously provide accurate local sound velocity profile correction fields, online calibration of sensor error parameters, and probability assessment of target carrier displacement events.

Claims

1. A seabed spatiotemporal reference station, characterized in that, It includes a seabed base and a support frame placed on top of the seabed base. The upper end of the support frame is provided with a base and the lower end is provided with a pressure chamber. The center of the base is provided with an integrated communication and conduction transducer. Four acoustic hydrophones are evenly arranged around the integrated communication and conduction transducer. The four acoustic hydrophones are mounted on the base by L-shaped brackets. The outside of the base is provided with a support ring connecting the four L-shaped brackets.

2. The seabed spatiotemporal reference station according to claim 1, characterized in that, At least five seabed spatiotemporal reference stations form a seabed network. The seabed network has a square structure, and the five seabed spatiotemporal reference stations are respectively distributed at the four vertices and the center of the seabed network. The side length of the seabed network is the farthest acoustic signal range of the seabed spatiotemporal reference station.

3. The seabed spatiotemporal reference station according to claim 1, characterized in that, The pressure chamber is surrounded by buoys, and a release device connected to the seabed base is installed at the bottom of the pressure chamber.

4. A data processing method for a seabed spatiotemporal reference station according to any one of claims 1-3, characterized in that, Includes the following steps: S1: The integrated communication and conduction transducer sends a communication signal to the target carrier through the communication module, and calculates the communication time between the integrated communication and conduction transducer and the target carrier based on the clock information of the communication signal. S2: The integrated communication and navigation transducer immediately sends an acoustic signal to the target carrier, and the target carrier sends a feedback acoustic signal to the integrated communication and navigation transducer. The clock offset is calculated using the reception time and transmission time of the acoustic signal and the feedback acoustic signal. Based on the clock offset, the seabed time and space reference station is clocked, and the target carrier is given a time synchronization service. S3: After the seabed time and space reference station completes the time synchronization service for the target carrier, it uses the acoustic observation equation between the sea surface carrier and the seabed time and space reference station and the pressure-depth observation equation of the seabed time and space reference station to solve the time-based position sequence of the seabed time and space reference station, and determines whether the seabed time and space reference station has been displaced based on the Bayesian framework, and performs reference position calibration for the seabed time and space reference station that has been displaced. S4: After completing the benchmark calibration of the seabed spatiotemporal reference station, locate the underwater target carrier based on its position on the seabed baseline network, and obtain the target carrier's position information; specifically: When the target carrier can receive acoustic signals from at least two seabed spatiotemporal reference stations in the seabed network, the position information of the target carrier can be obtained by constructing acoustic observation equations and pressure-depth observation equations between the two seabed spatiotemporal reference stations and the target carrier. When the target carrier can only receive the acoustic signal from one seabed time-space reference station in the seabed base network, the target carrier is located using the seabed time-space reference station according to the ultra-short baseline acoustic positioning mode, and the location information of the target carrier is sent to the target carrier through the communication module.

5. The data processing method for the seabed spatiotemporal reference station according to claim 4, characterized in that, Step S1 includes: S11: The integrated communication and conduction transducer sends a communication signal to the target carrier via the communication module. The communication signal carries clock information. After receiving the communication signal, the target carrier immediately sends a feedback communication signal to the integrated communication and conduction transducer. The integrated communication and conduction transducer records the time when it receives the feedback communication signal. t 2; S12: Based on the time information in the communication signal t 1. Calculate the communication time between the integrated communication and conduction transducer and the target carrier. .

6. The data processing method for the seabed spatiotemporal reference station according to claim 5, characterized in that, Step S2 includes: S21: After receiving the feedback communication signal, the integrated communication transducer immediately sends an acoustic signal to the target carrier and records the acoustic signal transmission time. After the target carrier receives the acoustic signal, it records the time of acoustic signal reception. The target carrier immediately transmits a feedback acoustic signal to the seabed time-space reference station and records the transmission time of the feedback acoustic signal. Four acoustic hydrophones received feedback signals, and the four acoustic hydrophones recorded the reception time of the feedback signals. ; S22: Select four receiving times Outliers in; Calculate the four reception times average ; Calculate the four reception times Compared with the average Compared to the offset rate ; ； in, i This is the serial number for the acoustic hydrophone. For the first i The reception time of the acoustic signal feedback from the acoustic hydrophone; Set the threshold for the offset rate. ,like Then determine the first i The reception time of the acoustic hydrophone feedback signal If it is an outlier, then determine the first one. i The reception time of the acoustic hydrophone feedback signal This is a normal value; Receiving time Delete outliers and retain the reception time. The normal value, and the retained reception time is calculated. Number of normal values n ,like If the signal is positive, proceed to step S5; otherwise, return to step S3 and the integrated transducer retransmits the acoustic signal to the target carrier. S23: Calculate reception time average of normal values ; S24: Utilizing launch time Reception time Launch time and average Calculate clock offset The seabed time and space reference station is based on the clock offset. To calibrate the clock of the seabed time and space reference station and provide time service to the target carrier; 。 7. The data processing method for the seabed spatiotemporal reference station according to claim 6, characterized in that, Step S3 includes: S31: After the seabed time and space reference station completes the time synchronization service for the target carrier, it uses the spatial three-dimensional coordinates of the sea surface carrier... Constructing the acoustic observation equations for the seabed spatiotemporal reference station: ； in, The spatial three-dimensional coordinates of the seabed spatiotemporal reference station. The round-trip observation propagation time of the sound signal. The spatial trajectory of the sound signal. To vary with depth z The changing speed of the sound signal This is the profile correction amount for the velocity of the sound signal. Based on the historical acoustic signal speed, s To propagate spatial trajectory An infinitesimal arc-length infinitesimal element; Spatial three-dimensional coordinates of sea surface carrier Spatial three-dimensional coordinates of the seabed time and space reference station Connect the lines, and establish a local two-dimensional coordinate system in the two-dimensional vertical plane of the connecting lines. The spatial trajectory of the sound signal propagation is then defined. Satisfy the ray tracking equation: ； in, x The horizontal distance within the local two-dimensional coordinate system. The angle between the tangent of the sound ray in the spatial trajectory of the sound signal and the horizontal direction; S32: Constructing the pressure-depth observation equation between the surface carrier and the seabed spatiotemporal reference station: ； in, The instantaneous water depth is predicted by a pressure sensor at the location of the seabed spatiotemporal reference station. Based on three-dimensional spatial coordinates Transformation function for converting ground altitude. These are the tidal water level, the non-tidal sea level, and the residual water level, respectively. S33: Predicted instantaneous water depth The position vector of the seabed spatiotemporal reference station based on time series is obtained by inputting the acoustic observation equation. ; Obtain the seabed spatiotemporal reference station from time 1 to N Position sequence And based on the Bayesian framework, calculate at each candidate time point The posterior probability of a displacement event occurring at an underwater spatiotemporal reference station; ； in, Let be the likelihood function. Candidate time points Long-term linear motion velocity in the first and second phases Candidate time points The prior probability distribution, Candidate time points The posterior probability of a displacement event occurring at an underwater spatiotemporal reference station; S34: Set the threshold for the posterior probability ,like Then, the candidate time point of the seabed spatiotemporal reference station is determined. If displacement occurs, the reference position of the seabed time-space reference station where displacement occurred is determined; otherwise, no displacement has occurred.

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