A remotely controllable seabed observation system with heterogeneous communication cascade and its data transmission method

Abstract

This invention discloses a remotely controllable seabed observation system with heterogeneous communication cascades and its data transmission method. The system includes distributed monitoring nodes, AUV mobile monitoring nodes, a relay transmission module, and a shore-based receiving system. The relay transmission module comprises, from bottom to top, a bottom-level base station connected by a zero-buoyancy coaxial cable, a buoyancy-self-balancing intermediate base station, and a dual-satellite backup controllable bidirectional communication base station. The relay transmission module has two operating modes: seabed communication mode and surface communication mode. In seabed communication mode, the dual-satellite backup controllable bidirectional communication base station submerges to a specified depth below the sea surface. In surface communication mode, the dual-satellite backup controllable bidirectional communication base station rises to the surface. This invention provides a remotely controllable seabed observation local area network with controllable monitoring strategies and operating parameters, achieving cross-media communication between sea and air through multiple cascaded links, and remotely controlling the operating parameters of distributed monitoring nodes and mobile monitoring AUVs.

Description

Technical Field

[0001] This invention belongs to the field of marine environmental monitoring technology, specifically relating to a remotely controllable seabed observation system with heterogeneous communication cascade and its data transmission method. Background Technology

[0002] Marine environmental monitoring includes monitoring of hydrological and water quality elements. By detecting and analyzing these elements, we can understand the types and concentrations of pollutants in the sea, as well as their migration and transformation patterns, and propose technical means and remedial measures for pollution prevention and control. Current marine environmental monitoring technologies include submarine cable observation technology, AUV-based marine observation technology, and marine buoy monitoring networks. Submarine cable observation technology uses cables laid on the seabed to connect and power various marine observation instruments and equipment, while simultaneously transmitting observation data to shore-based platforms. However, current submarine cable observation technology has the following drawbacks: the initial investment in submarine cables is enormous, requiring substantial financial support for cable laying and related instruments; to transmit data from the seabed to shore-based platforms, most submarine cable observation technologies are deployed near the coast; and the long-term maintenance and recovery of this large network system is difficult in the long run. AUV-based marine observation technology uses mobile AUVs to monitor marine environmental data. AUVs can surface to transmit data via wireless communication or submerge underwater to collect data via underwater acoustic communication. However, this method only monitors the environment and transmits data within a certain range of the AUV, and cannot monitor the seabed or transmit seabed monitoring data to shore-based platforms. Furthermore, traditional AUVs store data in their own storage modules. Shore-based platforms need to retrieve the AUV data to obtain it, making real-time data transmission difficult. In recent years, marine buoy monitoring networks have been widely deployed. However, marine buoy monitoring has limited coverage, making it difficult to acquire seabed equipment data and transmit it to shore-based platforms. They are also easily affected by sea waves and drift away from their designated locations. Moreover, marine buoys float on the surface for extended periods, lacking concealment and severely impacting ship navigation, significantly limiting their application in military, marine observation, and other fields. Large-scale underwater three-dimensional environmental monitoring must rely on the organic combination of distributed fixed-point acquisition and large-scale mobile acquisition. Therefore, this invention proposes a remotely controllable seabed observation system based on heterogeneous communication cascading. Summary of the Invention

[0003] The purpose of this invention is to provide a remotely controllable seabed observation system with heterogeneous communication cascade, based on the shortcomings of existing marine environmental monitoring technologies.

[0004] A heterogeneous communication cascaded remotely controllable seabed observation system includes distributed monitoring nodes, an AUV mobile monitoring node, a relay transmission module, and a shore-based receiving system. The relay transmission module comprises, from bottom to top, a bottom-level base station connected by a zero-buoyancy coaxial cable, a buoyancy-self-balancing intermediate base station, and a dual-satellite backup controllable bidirectional communication base station. The dual-satellite backup controllable bidirectional communication base station is installed in the underwater mooring. The relay transmission module can control its own ascent and descent.

[0005] The relay transmission module has two operating modes: seabed communication mode and surface communication mode. In seabed communication mode, the relay transmission module submerges to a specified depth below the sea surface, enabling the buoyancy-self-balancing intermediate base station to communicate with the distributed monitoring nodes, and the bottom base station to communicate with the AUV mobile monitoring nodes. In surface communication mode, the relay transmission module rises to the sea surface and communicates with the shore-based receiving system via Tiantong satellite and / or Beidou satellite, with dual-satellite backup controllable bidirectional communication base stations. The zero-buoyancy coaxial cable is an optoelectronic composite cable.

[0006] Preferably, the buoyancy self-balancing adjustment intermediate base station communicates with the distributed monitoring nodes via underwater acoustic communication; the underlying base station communicates with the cruising AUV mobile monitoring nodes via laser communication.

[0007] Preferably, the fixed-point monitoring node is equipped with a first underwater acoustic communication unit, a node processor, a pressure sensor, an underwater positioning module, a turbidity sensor, and an underwater camera unit. The pressure sensor is used to locate water depth data; the underwater positioning module is used to acquire and confirm the location of the distributed monitoring nodes; the turbidity sensor is used to collect concentration data of the seabed plume; and the underwater camera unit is used to acquire image data of the seabed environment. The first underwater acoustic communication unit communicates with a second underwater acoustic communication unit located in the buoyancy self-balancing intermediate base station.

[0008] Preferably, the dual-satellite backup controllable bidirectional communication base station includes a first EDSL communication circuit, a communication processing circuit, a Tiantong communication module, and a Beidou communication module. The first EDSL communication circuit is connected to the second EDSL communication circuit of the buoyancy self-balancing intermediate base station via a zero-buoyancy coaxial cable. The communication processing circuit receives the communication data output from the second EDSL communication circuit and organizes the communication data into communication data packets; the data output interface of the communication processing circuit is connected to the Tiantong communication module and the Beidou communication module. When the relay transmission module is in sea surface communication mode, the Tiantong communication module communicates with the Tiantong satellite. The Beidou communication module communicates with the Beidou satellite.

[0009] The shore-based receiving system includes a satellite signal receiving module, a processor, and a host computer. The satellite signal receiving module includes a satellite signal receiver and a data conversion module. The satellite signal receiver communicates with BeiDou and TianTong satellites. The satellite signal receiver is connected to the data conversion module. The data conversion module is used to parse the satellite signals and send them to the processor, and to modulate the signals transmitted by the processor into satellite signals. The processor is used to receive the signals processed by the data conversion module and upload them to the host computer, and to send signals from the host computer to the data conversion module.

[0010] Preferably, the buoyancy self-balancing intermediate base station includes a second EDSL communication circuit, a third EDSL communication circuit, a second underwater acoustic communication unit, a first system scheduling gateway, and a buoyancy levitation control circuit. The second EDSL communication circuit is connected to the first EDSL communication circuit of the dual-satellite backup controllable bidirectional communication base station via a zero-buoyancy coaxial cable. The third EDSL communication circuit is connected to the fourth EDSL communication circuit of the underlying base station via a zero-buoyancy coaxial cable. The second underwater acoustic communication unit is connected to the second central processing circuit and communicates with the distributed monitoring nodes. The first system scheduling gateway connects the second EDSL communication circuit, the third EDSL circuit, the second underwater acoustic communication unit, and the buoyancy levitation control circuit. The buoyancy levitation control circuit includes a second central processing circuit, a motor driver, and a motor. The motor controls the relay transmission module to rise or sink.

[0011] The data transmission method of this heterogeneous communication cascaded remotely controllable seabed observation system includes the following steps:

[0012] When the relay transmission module needs to communicate with the distributed monitoring nodes and the AUV mobile monitoring nodes, the relay transmission module enters the seabed communication mode and dives to the preset depth; the data received by the bottom base station is sent to the buoyancy self-balancing intermediate base station through the zero buoyancy coaxial cable; the data received by the buoyancy self-balancing intermediate base station is sent to the dual-satellite backup controllable bidirectional communication base station for storage through the zero buoyancy coaxial cable.

[0013] When the relay transmission module communicates with the shore-based receiving system, the relay transmission module enters the sea surface communication mode; the dual-satellite backup controllable two-way communication base station, which floats to the surface, uploads data to the shore-based receiving system via Tiantong satellite or Beidou satellite.

[0014] The process of communication via a zero-buoyancy coaxial cable is as follows:

[0015] Step 1: Evaluate the two channels of the communication link using a channel evaluation model. The two channels are the optical transmission channel and the electrical transmission channel.

[0016] Step 2: Channel allocation.

[0017] The scores of optical and electrical transmission channels are compared. The channel with the higher score is selected as the primary channel, and the channel with the lower score is selected as the secondary channel.

[0018] Step 3: Determine if the data to be transmitted is a retransmitted data packet; if yes, skip step 4 and proceed directly to step 5; otherwise, execute steps 4 and 5 in sequence. A retransmitted data packet is data that failed to be sent.

[0019] Step 4: Data packet length allocation and data packet segmentation.

[0020] The data to be transmitted is divided into a main line transmission part and a secondary line transmission part and packaged into main line data packets and secondary line data packets.

[0021] Step 5: Data is transmitted between the main line and the secondary line.

[0022] The primary line transmits two parts in a single data transmission. The first part includes the primary line data packet's content, number, channel quality, packet length, and CRC checksum. The second part includes the secondary line data packet's number, channel quality, packet length, and CRC checksum. The secondary line transmits the same content in a single data transmission, including the secondary line data packet's content, number, channel quality, packet length, and CRC checksum.

[0023] Preferably, the channel evaluation model employs a neural network model. The input layer neurons of the channel evaluation model represent normalized values ​​for channel quality, channel occupancy, data volume, and data priority for each channel segment. The hidden layer of the channel evaluation model is a fully connected layer, connecting neurons from multiple input layers, and uses the sigmoid function as the activation function. The output layer neurons of the channel evaluation model represent the normalized results of each channel score.

[0024] Preferably, in step three, the failure to send data packets is determined by whether the data receiving end of the communication sends a retransmission signal.

[0025] Preferably, in step four, the data length L of the mainline data packet and the secondaryline data packet is determined based on the scores of the mainline and the secondaryline. i :

[0026]

[0027] Where i = 1, 2; For floor operations, the unit is bytes; L1 and L2 are the data packet length values ​​of the main line and the secondary line, respectively; Score1 and Score2 are the score values ​​of the main line and the secondary line, respectively; C is the conversion constant.

[0028] Based on the data length L of the main line data packet and the secondary line data packeti The transmitted data is divided into mainline data packets and secondaryline data packets.

[0029] As a preferred option, the specific process of communication between the dual-satellite backup controllable bidirectional communication base station and the shore-based receiving system is as follows:

[0030] (1) Priority management is performed on the data to be transmitted; the priority is divided into four levels; the data signals are transmitted in order of priority from high to low.

[0031] (2) Before transmitting data, channel quality detection is performed on the BeiDou satellite link and the TianTong satellite link respectively to obtain the remaining bandwidth value and channel quality value of the transmission channel of the BeiDou satellite link and the TianTong satellite link respectively.

[0032] (3) When the amount of data transmitted is less than the short message length of the BeiDou satellite link and the channel quality of the BeiDou satellite link is stable, the BeiDou satellite link shall be used for transmission.

[0033] When the data volume exceeds the short message length of the BeiDou satellite link, the dual-satellite links are invoked for dynamic data transmission. The process involves dynamically dividing the data packet length (Len) based on the remaining bandwidth and channel quality values ​​of the BeiDou and TianTong satellite links. i Number the data packet and complete the submission; data packet length Len i The expression is:

[0034]

[0035] Where i = 1, 2; For floor operations; Len1 and Len2 are the data packet length values ​​of the BeiDou satellite link and the TianTong satellite link, respectively; BWres1 and BWres2 are the remaining bandwidth values ​​of the transmission channels of the BeiDou satellite link and the TianTong satellite link, respectively; BW1 and BW2 are the total bandwidth values ​​of the transmission channels of the BeiDou satellite link and the TianTong satellite link, respectively; Qc1 and Qc2 are the channel quality values ​​of the BeiDou satellite link and the TianTong satellite link, respectively; Qcmax1 and Qcmax2 are the maximum channel quality values ​​of the BeiDou satellite link and the TianTong satellite link, respectively; α and β are the importance weights of the remaining bandwidth and channel quality of the transmission channels, respectively, α+β=1; C1 and C2 are the conversion constants corresponding to the BeiDou satellite link and the TianTong satellite link, respectively.

[0036] (4) Data transmission. When the two satellite links are used together for dynamic data transmission, the BeiDou satellite link transmits two parts of data; the first part of the data is the data packet allocated to the BeiDou satellite link for transmission; the second part of the data is the verification information of the data packet allocated to the TianTong satellite link for transmission, including the data packet number, data packet length, TianTong satellite module channel quality value and CRC check code.

[0037] (5) The shore-based receiving system receives data transmitted by the BeiDou satellite link and / or the TianTong satellite link, combines and verifies all data according to the verification information in the data transmitted by the BeiDou satellite link, and returns the label of the data packet with the verification error, requiring the dual-satellite backup controllable bidirectional communication base station to retransmit the data packet with the error.

[0038] The beneficial effects of this invention are as follows:

[0039] 1. This invention provides a remotely controllable seabed observation local area network with monitoring strategies and operating parameters. It realizes cross-media communication between sea and air through multiple cascaded links, and remotely controls the operating parameters of distributed monitoring nodes and mobile monitoring AUVs.

[0040] 2. In the present invention, after channel evaluation when using optical-electric composite cable for data transmission, important data and verification information of secondary data are transmitted through channels with high scores, thereby greatly improving the reliability of data transmission and the traceability of transmission errors.

[0041] 3. This invention provides an underwater heterogeneous cascaded network that combines satellite communication, coaxial cable communication, underwater acoustic communication and underwater laser communication, realizing a three-dimensional coverage network covering the shore-based, airspace, water surface and underwater areas.

[0042] 4. This invention provides a dual-satellite backup controllable bidirectional communication base station, which combines the different characteristics of Tiantong satellite and Beidou satellite to achieve high bandwidth and high reliability communication, and is equipped with a liftable control device to achieve communication concealment. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the remotely controllable seabed observation system of the present invention.

[0044] Figure 2 This is a flowchart illustrating the communication process using a zero-buoyancy coaxial cable in this invention.

[0045] Figure 3 This is a schematic diagram illustrating the channel allocation strategy of the present invention during communication via a zero-buoyancy coaxial cable.

[0046] Figure 4 This is a flowchart illustrating the communication process between the dual-satellite backup controllable bidirectional communication base station and the shore-based receiving system in this invention.

[0047] Figure 5 This is a schematic diagram of the deep-sea remotely controlled local area network structure formed by the present invention. Detailed Implementation

[0048] The present invention will be further described below with reference to the accompanying drawings.

[0049] like Figure 1 As shown, a heterogeneous communication cascaded remotely controllable seabed observation system includes a distributed monitoring node 100, an AUV mobile monitoring node 200, a relay transmission module, and a shore-based receiving system 600. The relay transmission module includes, from bottom to top, a bottom-level base station 300, a buoyancy-self-balancing intermediate base station 400, and a dual-satellite backup controllable two-way communication base station 500, connected sequentially by a zero-buoyancy coaxial cable 700. The dual-satellite backup controllable two-way communication base station 500 is installed in a mooring. The buoyancy-self-balancing intermediate base station 400 can control the ascent or descent of the dual-satellite backup controllable two-way communication base station 500 via a motor.

[0050] The relay transmission module has two operating modes: seabed communication mode and surface communication mode. In seabed communication mode, the dual-satellite backup controllable bidirectional communication base station 500 submerges to a designated depth below the sea surface, enabling it to communicate with the underlying base station 300 and the distributed monitoring node 100. The buoyancy-self-balancing intermediate base station 400 communicates with the distributed monitoring node 100 via underwater acoustics, while the underlying base station 300 communicates with the AUV mobile monitoring node 200 patrolling the seabed via laser. In surface communication mode, the dual-satellite backup controllable bidirectional communication base station 500 surfaces and communicates with the shore-based receiving system 600 via Tiantong or Beidou satellites, transmitting data collected from the seabed to the shore-based receiving system 600.

[0051] The zero-buoyancy coaxial cable 700 is an optoelectronic composite cable, containing both optical fiber and twisted-pair cable. Therefore, the zero-buoyancy coaxial cable 700 connects the underlying base station 300 to the buoyancy self-balancing intermediate base station 400, and the buoyancy self-balancing intermediate base station 400 to the dual-satellite backup controllable bidirectional communication base station 500, with both optical fiber channels and twisted-pair cable channels. Optical fiber enables high-bandwidth data transmission, but it is susceptible to environmental interference in deep sea conditions, which may affect signal transmission. Twisted-pair cable offers stable signal transmission and high channel reliability, but its data transmission bandwidth is relatively low.

[0052] The data transmission method of this heterogeneous communication cascaded remotely controllable seabed observation system includes the following steps:

[0053] When the relay transmission module needs to communicate with the distributed monitoring node 100 and the AUV mobile monitoring node 200 to receive data or send commands, the relay transmission module enters the seabed communication mode and dives to a preset depth. The data received by the bottom base station 300 is sent to the buoyancy self-balancing intermediate base station 400 through the zero buoyancy coaxial cable 700. The data received by the buoyancy self-balancing intermediate base station 400 is sent to the dual-satellite backup controllable bidirectional communication base station 500 for storage through the zero buoyancy coaxial cable 700.

[0054] When the relay transmission module needs to upload data to the shore-based receiving system 600, or receive control commands sent by the shore-based receiving system 600, the relay transmission module enters the sea surface communication mode; the surface-based dual-satellite backup controllable two-way communication base station 500 uploads data to the shore-based receiving system 600 via Tiantong satellite or Beidou satellite.

[0055] To ensure high-bandwidth and high-quality data transmission, this embodiment introduces a channel evaluation model to evaluate the channel of the two composite cable segments in the "bottom-layer base station - buoyancy-self-balancing intermediate base station - dual-satellite backup controllable bidirectional communication base station" link.

[0056] like Figure 2 and 3 As shown, the communication process via the zero-buoyancy coaxial cable 700 is as follows:

[0057] Step 1: Evaluate the two channels of the communication link using a channel evaluation model. The two channels are the optical transmission channel and the electrical transmission channel.

[0058] The channel evaluation model employs a neural network. The input layer neurons represent normalized quantized values ​​for channel quality, channel occupancy, data volume, and data priority for each channel segment. The hidden layer is a fully connected layer, connecting neurons from multiple input layers, and uses the sigmoid function as the activation function. The output layer neurons represent the normalized result of each channel score, specifically a value between 0 and 1, retaining four decimal places.

[0059] Step 2: Channel allocation.

[0060] The scores of optical and electrical transmission channels are compared. The channel with the higher score is selected as the primary channel, and the channel with the lower score is selected as the secondary channel.

[0061] Step 3: Determine if the data to be transmitted is a retransmission data packet. If yes, skip step 4 and proceed directly to step 5. If no, execute steps 4 and 5 in sequence. A retransmission data packet is data that has failed to be transmitted once or multiple times, and the primary and secondary data packets were already separated during the initial transmission.

[0062] Step 4: Data packet length allocation and data packet segmentation.

[0063] Based on the scores of the primary and secondary lines, the transmitted data is divided into primary line transmission parts and secondary line transmission parts and packaged into primary line data packets and secondary line data packets. The data importance of the primary line data packets is higher than that of the secondary line data packets. The data length L of the primary line data packets and secondary line data packets is... i :

[0064]

[0065] Where i = 1 or 2, corresponding to the main line and the secondary line respectively. For floor function operations, the unit is bytes; L1 and L2 are the packet length values ​​for the main line and the secondary line, respectively; Score1 and Score2 are the score values ​​for the main line and the secondary line, respectively; C is a conversion constant with a value of 1024. i The normalized value is retained to four decimal places. Therefore, the data packet length value L... i The result ranges from 0 to 1024 bytes. This indicates that after the "packet length allocation" strategy step, the system can allocate a byte length value within the range of 0 to 1024 bytes to the packet length in the corresponding channel transmission number protocol. Finally, the data is packaged according to the values ​​determined above.

[0066] Step 5: Data is transmitted between the main line and the secondary line.

[0067] like Figure 3 As shown, the content transmitted by the mainline in a single data transmission consists of two parts. The first part is the mainline data packet and its related information, including the mainline data packet number, mainline channel quality, mainline data packet length, mainline data packet, and mainline CRC checksum. The mainline data packet length is determined by the "data packet length allocation" step.

[0068] The second part contains information about the secondary line data packets other than the data content, including the secondary line data packet number, secondary line channel quality, secondary line data packet length, and secondary line data CRC checksum. The secondary line data packet length is determined by the "data packet length allocation" step.

[0069] The secondary line transmits only the secondary line data packet and its related information in a single data transmission, including the secondary line data packet number, secondary line channel quality, secondary line data packet length, secondary line data packet, and secondary line CRC checksum. The secondary line data packet length is determined by the "data packet length allocation" step. It is worth noting that this strategy only distinguishes between the primary and secondary lines after comparing the channels; the content of the transmitted data is determined by the "data packet length allocation" step.

[0070] The inclusion of the second part of the above content in the data transmitted on the main line with a high score is to ensure the accuracy of the data transmitted on the secondary line with a low score.

[0071] The dual-satellite backup controllable bidirectional communication base station and the shore-based receiving system utilize the different characteristics of BeiDou and Tiantong satellites to achieve high-bandwidth and high-reliability communication between the two base stations. While the BeiDou satellite module communication link offers high reliability, it can only transmit short messages and cannot handle high-speed transmission of large amounts of data. The Tiantong satellite module can achieve high-bandwidth data transmission, but the integrity of the transmitted data is uncertain. If the link is interfered with or interrupted due to environmental factors while using the Tiantong module link for data transmission, the receiver cannot determine the integrity and accuracy of the data. Therefore, this system dynamically adjusts the link based on the amount of data transmitted and the link quality.

[0072] like Figure 4 As shown, the method for transmitting data is as follows:

[0073] (1) Prioritize data signals, setting high-real-time requirements to high priority and moderate-real-time requirements to low priority. Priority management is divided into four levels: strong real-time, moderate real-time, weak real-time, and no real-time. Data signals are transmitted sequentially according to their real-time requirements.

[0074] (2) Before transmitting data, channel quality is tested on the two-star link respectively.

[0075] (3) When the amount of data transmitted is less than the short message length of the Beidou satellite module and the channel quality is stable, the Beidou satellite module should be used first to ensure the reliability of data transmission.

[0076] (4) When the amount of data exceeds the short message length of the Beidou satellite module, it is necessary to call the dual-satellite link for dynamic data transmission.

[0077] (5) Before transmitting data signals, the communication base station performs dual-star link channel quality detection to obtain the remaining bandwidth value and channel quality value of the transmission channel;

[0078] (6) When the BeiDou satellite module and the TianTong satellite module simultaneously request data transmission from the system, the system will dynamically allocate the data packet length Len based on the remaining bandwidth and channel quality of each module's transmission channel. i Number the data packets and complete the submission; specifically, divide the data packet length into Len. i The formula is:

[0079]

[0080] Where i = 1, 2; For floor operations, the unit is bytes; Len1 and Len2 are the data packet length values ​​of the BeiDou satellite module and the TianTong satellite module, respectively; BWres1 and BWres2 are the remaining bandwidth values ​​of the transmission channels of the BeiDou satellite module and the TianTong satellite module, respectively; BW1 and BW2 are the total bandwidth values ​​of the transmission channels of the BeiDou satellite module and the TianTong satellite module, respectively; Qc1 and Qc2 are the channel quality values ​​of the BeiDou satellite module and the TianTong satellite module, respectively; Qcmax1 and Qcmax2 are the maximum channel quality values ​​of the BeiDou satellite module and the TianTong satellite module, respectively; α and β are normalization coefficients, satisfying α+β=1; C1 and C2 are the conversion constants corresponding to the BeiDou satellite module and the TianTong satellite module, respectively.

[0081] (7) During transmission, the BeiDou module performs two tasks: reliable transmission of small data packets and carrying information corresponding to data packets already sent by the TianTong satellite module, including data packet number, data packet length, channel quality of the TianTong satellite module under the current data packet transmission, and CRC checksum. The TianTong module continuously performs high-bandwidth transmission of data packets;

[0082] (8) The shore-based receiving system combines and verifies the received data packets according to the data packet information transmitted by the Beidou module, and sends back the label information of the data packets with verification errors to request the communication base station to retransmit the erroneous data packets. In this step, it is determined whether there are any retransmitted data packets. If there are, return to step (5) and send the retransmitted data packets; if not, proceed to step (9).

[0083] (9) After the module completes this data transmission, it determines whether the data has been sent completely. If not, it requests data to be sent to the system again. The system re-evaluates the transmission bandwidth and channel quality of the module that submitted the request, allocates the data packet size, and completes the submission.

[0084] This enables dynamic data packet segmentation. Ultimately, it ensures the accuracy of data packets efficiently during high-bandwidth data transmission, achieving high-bandwidth and high-quality communication via the dual-satellite link.

[0085] like Figure 5 As shown, in this embodiment, multiple distributed monitoring nodes 100 are deployed in different areas of the observed seabed. They achieve distributed communication and wireless networking through long-distance underwater acoustic communication, transmitting the collected sensor data to the buoyancy self-balancing adjustment intermediate base station 400 in real time. The buoyancy self-balancing adjustment intermediate base station 400 utilizes long-distance repeaterless coaxial cable broadband communication technology to transmit the sensor data and camera image data together to the dual-satellite backup controllable bidirectional communication base station 500. The distributed monitoring nodes 100 are placed on the seabed as fixed monitoring points, enabling them to collect and monitor environmental data of the fixed points over time, thereby obtaining continuously changing environmental data of the fixed points.

[0086] The AUV mobile monitoring node 200 cruises the seabed according to a set route, collecting environmental data. It then transmits the collected sensor data and environmental images captured by the deep-sea camera to the bottom base station 300 via long-distance laser communication. The buoyancy self-balancing intermediate base station 400 receives and analyzes the underwater pressure data transmitted by the dual-satellite backup controllable two-way communication base station 500 and the sensing data and camera image data transmitted by the bottom base station 300, controlling the ascent and descent of the dual-satellite backup controllable two-way communication base station 500. Finally, after the dual-satellite backup controllable two-way communication base station 500 rises to the sea surface, it transmits the data in real-time to the shore-based service platform via high-bandwidth satellite two-way communication, acquiring experimental monitoring data online for modeling and analysis. The shore-based receiving system 600 can also transmit control commands via a reverse link, enabling remote adjustment of monitoring functions and strategies.

[0087] The distributed monitoring nodes 100 consist of n units, each equipped with a first underwater acoustic communication unit, a node processor, and multiple sensors of various types. In this embodiment, the sensors configured in the distributed monitoring nodes 100 include a pressure sensor, an underwater positioning module, a turbidity sensor, and an underwater camera unit. The pressure sensor is used to locate water depth data; the underwater positioning module is used to acquire and confirm the location of the distributed monitoring nodes 100; the turbidity sensor is used to collect concentration data of the seabed plume; and the underwater camera unit is used to acquire image data of the seabed environment. The image data is used for evaluation of the seabed environment data. The first underwater acoustic communication unit is connected to the node processor via an RS-232 interface, enabling underwater acoustic communication between the node processor and the buoyancy self-balancing adjustment intermediate base station 400; thereby transmitting various data collected by the sensors to the buoyancy self-balancing adjustment intermediate base station 400 via coaxial cable communication; simultaneously, the buoyancy self-balancing adjustment intermediate base station 400 can also transmit control commands back to the distributed monitoring nodes 100 via underwater acoustic communication.

[0088] The underlying base station 300 includes a fourth EDSL communication circuit, a first laser communication unit, a second system scheduling gateway, a camera data acquisition circuit, a power management module, a data monitoring circuit, and a mode control circuit. The fourth EDSL communication circuit is connected to the third EDSL communication circuit of the buoyancy self-balancing intermediate base station 400 via a zero-buoyancy coaxial cable 700, enabling data transmission between the underlying base station 300 and the buoyancy self-balancing intermediate base station 400. The first laser communication unit communicates with the second laser communication unit of the AUV mobile monitoring node 200 via laser, enabling data transmission between the underlying base station 300 and the AUV mobile monitoring node 200. The second system scheduling gateway connects all modules, circuits, and devices, enabling unified task scheduling and data storage for the connected components. The camera data acquisition circuit is connected to a deep-sea particle camera, a sediment profile camera, and a deep-sea stereo vision camera, and these three deep-sea cameras acquire deep-sea environmental image data. The power management module supplies power to the various circuits and devices of the underlying base station 300 through internal voltage conversion. The data monitoring circuit is responsible for receiving, parsing, and verifying the integrity and accuracy of the data. The mode control circuit makes a comprehensive judgment and switches modes based on the data transmitted by the AUV mobile monitoring node 200 and the dataset from the buoyancy self-balancing intermediate base station 400. The relay transmission module has three modes: idle mode, data receiving mode, and data transmission mode.

[0089] The bottom-level base station 300 acts as the main monitoring node, using a deep-sea camera to collect deep-sea environment image data; it receives monitoring data from the AUV mobile monitoring node 200 according to mode switching; it packages the data into communication data packets and transmits them to the buoyancy self-balancing adjustment intermediate base station 400 through the zero-buoyancy coaxial cable 700; it can also transmit control signals from the buoyancy self-balancing adjustment intermediate base station 400 to the AUV mobile monitoring node 200, realizing remote controllable monitoring strategies and operating parameters of the AUV mobile monitoring node 200.

[0090] The AUV mobile monitoring node 200 includes an AUV control system, a second laser communication unit, and a sensing and measurement device. The AUV control system includes a power management module, an AUV central processing system, and a power drive module. The power management module supplies power to various modules and equipment of the AUV through internal voltage conversion. The AUV central processing system can control the state of the AUV, specifically by calculating the current and future motion states based on control signals, and then transmitting the motion state data to the power drive module to achieve motion control, real-time monitoring and adjustment of the AUV's motion state; the AUV central processing system can receive and process data transmitted from external devices; and the AUV central processing system can organize the data into communication data packets. The second laser communication unit communicates with the first laser communication unit of the underlying base station 300 via underwater acoustic transmission, enabling data exchange between the AUV mobile monitoring node 200 and the underlying base station 300. The transmitted data format is a communication data packet organized by the central processing system. The sensing and measurement device mainly refers to various marine sensors, acoustic detection devices, etc., used for surface detection of the navigating area.

[0091] The AUV mobile monitoring node 200, as a mobile monitoring node, can move over a wider seabed area to collect and monitor environmental data within its range, thus enabling monitoring of a larger seabed area.

[0092] The buoyancy self-balancing intermediate base station 400 includes a second EDSL communication circuit, a third EDSL communication circuit, a second underwater acoustic communication device, a first system scheduling gateway, and a buoyancy levitation control circuit. The second EDSL communication circuit is connected to the first EDSL communication circuit of the dual-satellite backup controllable bidirectional communication base station 500 via a zero-buoyancy coaxial cable 700, enabling data transmission between the buoyancy self-balancing intermediate base station 400 and the dual-satellite backup controllable bidirectional communication base station 500. The third EDSL communication circuit is connected to the fourth EDSL communication circuit of the underlying base station 300 via the zero-buoyancy coaxial cable 700, enabling data transmission between the buoyancy self-balancing intermediate base station 400 and the underlying base station 300. The second underwater acoustic communication device is connected to the second central processing circuit inside the buoyancy self-balancing intermediate base station 400 via an RS232 interface, and communicates externally with the distributed monitoring node 100 via underwater acoustic communication, enabling data transmission with the distributed monitoring node 100. The first system scheduling gateway connects the second EDSL communication circuit, the third EDSL communication circuit, the second underwater acoustic communication device, and the snorkeling and levitation control circuit, enabling unified task scheduling and data storage for the connected components. The snorkeling and levitation control circuit includes a second central processing circuit, a motor driver, and a motor. Upon receiving control signals transmitted from the dual-satellite backup controllable bidirectional communication base station 500 via the zero-buoyancy coaxial cable 700, the second central processing circuit of the snorkeling and levitation control circuit parses the data packets and sends drive signals to the control motor driver, thereby controlling the motor to perform forward or reverse rotation, achieving control over the ascent and descent of the dual-satellite backup controllable bidirectional communication base station 500.

[0093] The buoyancy self-balancing adjustment allows the intermediate base station 400 to controllably rise and fall, balancing the needs of real-time and covert communication. It uses a long-distance, repeaterless armored coaxial cable to achieve megabit-level communication with the underlying base station 300. It is equipped with an underwater acoustic communication modem to achieve local area network interconnection and remote control with multiple underlying slave stations.

[0094] The dual-satellite backup controllable bidirectional communication base station 500 features controllable buoyancy and satellite backup. The dual-satellite backup controllable bidirectional communication base station 500 includes a first EDSL communication circuit, a communication processing circuit, a status detection circuit, a Tiantong communication module HTDM1431, and a Beidou communication module RD8500X1. The first EDSL communication circuit is connected to the second EDSL communication circuit of the buoyancy self-balancing intermediate base station 400 via a zero-buoyancy coaxial cable 700, enabling data transmission between the dual-satellite backup controllable bidirectional communication base station 500 and the buoyancy self-balancing intermediate base station 400. The communication processing circuit functions to receive data from the buoyancy self-balancing intermediate base station 400 and reply with a response signal to ensure data reliability; organize the data into communication data packets; send the data packets to the shore-based receiving system 600 via the Tiantong communication module HTDM1431; and receive control signals sent by the shore-based receiving system 600 via the Beidou communication module RD8500X1 and reply with a response signal to the shore-based receiving system 600. The status detection circuit includes a power management circuit, a processor circuit 1, and a pressure sensor MS5837. The dual-satellite backup controllable two-way communication base station 500 has four status modes: surfacing mode, sinking mode, data transmission mode (sending seabed data to the shore-based receiving system 600), and control signal transmission mode (the shore-based receiving system 600 sends control signals to the seabed equipment). The power management circuit converts the voltage input from the lithium battery into the voltage required by the processor circuit and the pressure sensor MS5837. The pressure sensor MS5837 transmits water depth data to the processor via I2C. The processor circuit 1 switches the status mode according to the received data.

[0095] The Tiantong satellite communication module HTDM1431 has a high communication rate and bandwidth. The Beidou communication module RD8500X1 has a relatively reliable data link. Combining the characteristics of these two satellites, the dual-satellite backup controllable bidirectional communication base station 500 system can dynamically select routes based on data volume and link quality, thereby achieving high-bandwidth and high-reliability communication.

[0096] The buoyancy self-balancing intermediate base station 400 changes its current state according to the mode signal of the dual-satellite backup controllable two-way communication base station 500, thereby controlling the motor to control the ascent and descent of the dual-satellite backup controllable two-way communication base station 500.

[0097] By controlling the surfacing and submerging of the dual-satellite backup controllable two-way communication base station 500, the system's resistance to wind and waves and its stealth capabilities can be improved. The dual-satellite backup controllable two-way communication base station 500 can lie submerged underwater and then surface to transmit satellite data; once data transmission is completed, the buoyancy self-balancing intermediate base station 400 can control the dual-satellite backup controllable two-way communication base station 500 to sink into the water.

[0098] The shore-based receiving system 600 includes a satellite signal receiving module, a processor, and a host computer. The satellite signal receiving module includes a satellite signal receiver and a data conversion module. The satellite signal receiver is connected to the data conversion module and is used to receive and transmit satellite signals. The data conversion module is used to parse the satellite signals and send them to the processor, and to modulate the signals transmitted by the processor into satellite signals. The processor is used to receive the signals processed by the data conversion module and to send signals from the host computer to the data conversion module. The host computer is used to display seabed environmental images, sensor data, base station depth, base station status mode, and distributed node positioning information, and to transmit control commands.

[0099] The shore-based receiving system 600 can receive communication data packets transmitted from the dual-satellite backup controllable two-way communication base station 500 and transmit control signals for seabed equipment to the dual-satellite backup controllable two-way communication base station 500 through the satellite signal receiving module, processor and host computer, thereby realizing cross-media two-way communication between sea and air.

[0100] In this embodiment, the distributed monitoring node 100, AUV mobile monitoring node 200, bottom base station 300, buoyancy self-balancing adjustment intermediate base station 400, dual-satellite backup controllable bidirectional communication base station 500 and shore-based receiving system 600 communicate with each other to realize a three-dimensional coverage network covering shore-based, airspace, water surface and underwater areas.

[0101] In this embodiment, the communication data packet format includes a frame header, type, data length, data, control signal, cyclic redundancy check (CRC), and tail. The frame header occupies 4 bytes, the type 4 bytes, the data length 16 bytes, the data 512 bytes, the control signal 8 bytes, the CRC 8 bytes, and the tail 4 bytes, totaling 556 bytes. The frame header and tail encapsulate the data to enable error detection, thereby improving the reliability of data transmission. The data length is the sum of the bytes occupied by the data and control signal. The data portion stores the data collected by the seabed equipment. The control signal portion stores the control signal data of the shore-based receiving system for the 600 pairs of underwater devices. Cyclic Redundancy Check (CRC) is an error detection and correction code mainly used to detect or verify errors that may occur after data transmission or storage, thereby improving the reliability of data transportation.

[0102] The communication in this embodiment adopts a data interaction protocol suitable for heterogeneous network cascaded communication. The main components, such as the shore-based receiving system 600, the dual-satellite backup controllable bidirectional communication base station 500, the buoyancy self-balancing adjustment intermediate base station 400, the distributed monitoring node 100, and the bottom base station 300, constitute a seabed observation local area network with remotely controllable monitoring strategies and working parameters. A network interaction protocol with guaranteed communication quality is designed according to different link characteristics to realize cross-media communication between sea and air, and remotely control the working parameters of the distributed monitoring node 100 and the AUV mobile monitoring node 200.

[0103] The uplink data transmitted by the data interaction protocol applicable to heterogeneous network cascaded communication is seabed environmental monitoring data transmitted from underwater equipment to the shore-based receiving system 600.

[0104] The first uplink transmission path of the data interaction protocol applicable to heterogeneous network cascaded communication is as follows: distributed monitoring node 100, buoyancy self-balancing adjustment intermediate base station 400, dual-satellite backup controllable bidirectional communication base station 500, and shore-based receiving system 600. Distributed monitoring node 100 sends data (Data), i.e., the aforementioned communication data packet, to buoyancy self-balancing adjustment intermediate base station 400; buoyancy self-balancing adjustment intermediate base station 400 replies with an acknowledgment signal (Rep); distributed monitoring node 100 then sends an acknowledgment character (ACK) to buoyancy self-balancing adjustment intermediate base station 400. Then, buoyancy self-balancing adjustment intermediate base station 400 sends data (Data) to dual-satellite backup controllable bidirectional communication base station 500; dual-satellite backup controllable bidirectional communication base station 500 receives the data and replies with an acknowledgment signal (Rep) to buoyancy self-balancing adjustment intermediate base station 400. Finally, the dual-satellite backup controllable two-way communication base station 500 continues to send data to the shore-based receiving system 600; the shore-based receiving system 600 replies with an acknowledgment signal (Rep); the dual-satellite backup controllable two-way communication base station 500 then sends an acknowledgment character (ACK) to the shore-based receiving system 600, indicating that the data transmission has been completed. This ultimately achieves communication between the distributed monitoring node 100 and the shore-based receiving system 600.

[0105] The second uplink path consists of a bottom-level base station 300, a buoyancy-self-balancing intermediate base station 400, a dual-satellite backup controllable bidirectional communication base station 500, and a shore-based receiving system 600. The bottom-level base station 300 sends data (Data) to the buoyancy-self-balancing intermediate base station 400; the buoyancy-self-balancing intermediate base station 400 replies with an acknowledgment signal (Rep). Then, the buoyancy-self-balancing intermediate base station 400 sends data (Data) to the dual-satellite backup controllable bidirectional communication base station 500; the dual-satellite backup controllable bidirectional communication base station 500 receives the data and replies with an acknowledgment signal (Rep) to the buoyancy-self-balancing intermediate base station 400. Finally, the dual-satellite backup controllable bidirectional communication base station 500 continues to send data (Data) to the shore-based receiving system 600; the shore-based receiving system 600 replies with an acknowledgment signal (Rep); the dual-satellite backup controllable bidirectional communication base station 500 then sends an acknowledgment character (ACK) to the shore-based receiving system 600, indicating that the data transmission has been completed. This ultimately achieves communication between the bottom-level base station 300 and the shore-based receiving system 600.

[0106] The third uplink path consists of AUV motion monitoring node 200, underlying base station 300, buoyancy self-balancing intermediate base station 400, dual-satellite backup controllable bidirectional communication base station 500, and shore-based receiving system 600. AUV motion monitoring node 200 sends data (Data) to underlying base station 300; underlying base station 300 replies with an acknowledgment signal (Rep); AUV motion monitoring node 200 then sends an acknowledgment character (ACK) to underlying base station 300. Then, underlying base station 300 sends data (Data) to buoyancy self-balancing intermediate base station 400; buoyancy self-balancing intermediate base station 400 replies with an acknowledgment signal (Rep). Next, buoyancy self-balancing intermediate base station 400 sends data (Data) to dual-satellite backup controllable bidirectional communication base station 500; dual-satellite backup controllable bidirectional communication base station 500 receives the data and replies with an acknowledgment signal (Rep) to buoyancy self-balancing intermediate base station 400. Finally, the dual-satellite backup controllable two-way communication base station 500 continues to send data to the shore-based receiving system 600; the shore-based receiving system 600 replies with an acknowledgment signal (Rep); the dual-satellite backup controllable two-way communication base station 500 then sends an acknowledgment character (ACK) to the shore-based receiving system 600, indicating that the data transmission has been completed. This ultimately achieves communication between the AUV mobile monitoring node 200 and the shore-based receiving system 600.

[0107] The downlink data transmitted in the heterogeneous cascaded communication data interaction protocol is the control signal transmitted from the shore-based receiving system 600 to the underwater equipment.

[0108] The first downlink transmission path of the heterogeneous cascaded communication data interaction protocol is as follows: shore-based receiving system 600, dual-satellite backup controllable bidirectional communication base station 500, buoyancy self-balancing adjustment intermediate base station 400, and distributed monitoring node 100. The shore-based receiving system 600 sends data (Data) to the dual-satellite backup controllable bidirectional communication base station 500; the dual-satellite backup controllable bidirectional communication base station 500 replies with an acknowledgment signal (Rep); the shore-based receiving system 600 then sends an acknowledgment character (ACK) to the dual-satellite backup controllable bidirectional communication base station 500. Then, the dual-satellite backup controllable bidirectional communication base station 500 sends data (Data) to the buoyancy self-balancing adjustment intermediate base station 400; after receiving the data, the buoyancy self-balancing adjustment intermediate base station 400 replies with an acknowledgment signal (Rep) to the dual-satellite backup controllable bidirectional communication base station 500. Finally, the buoyancy self-balancing intermediate base station 400 sends data to the distributed monitoring node 100; the distributed monitoring node 100 replies with an acknowledgment signal (Rep); the buoyancy self-balancing intermediate base station 400 then sends an acknowledgment character (ACK) to the distributed monitoring node 100. This ultimately enables the shore-based receiving system 600 to control the distributed monitoring node 100.

[0109] The second downlink transmission path is as follows: shore-based receiving system 600, dual-satellite backup controllable bidirectional communication base station 500, buoyancy self-balancing intermediate base station 400, and bottom-level base station 300. The shore-based receiving system 600 sends data (Data) to the dual-satellite backup controllable bidirectional communication base station 500; the dual-satellite backup controllable bidirectional communication base station 500 replies with an acknowledgment signal (Rep); the shore-based receiving system 600 then sends an acknowledgment character (ACK) to the dual-satellite backup controllable bidirectional communication base station 500. Then, the dual-satellite backup controllable bidirectional communication base station 500 sends data (Data) to the buoyancy self-balancing intermediate base station 400; the buoyancy self-balancing intermediate base station 400 receives the data and replies with an acknowledgment signal (Rep) to the dual-satellite backup controllable bidirectional communication base station 500. Finally, the buoyancy self-balancing intermediate base station 400 sends data (Data) to the bottom-level base station 300; the bottom-level base station 300 replies with an acknowledgment signal (Rep). Ultimately, the shore-based receiving system 600 controls the bottom-level base station 300.

[0110] The third downlink transmission path is as follows: shore-based receiving system 600, dual-satellite backup controllable bidirectional communication base station 500, buoyancy self-balancing adjustment intermediate base station 400, bottom-level base station 300, and AUV motion monitoring node 200. The shore-based receiving system 600 sends data (Data) to the dual-satellite backup controllable bidirectional communication base station 500; the dual-satellite backup controllable bidirectional communication base station 500 replies with an acknowledgment signal (Rep); the shore-based receiving system 600 then sends an acknowledgment character (ACK) to the dual-satellite backup controllable bidirectional communication base station 500. Then, the dual-satellite backup controllable bidirectional communication base station 500 sends data (Data) to the buoyancy self-balancing adjustment intermediate base station 400; the buoyancy self-balancing adjustment intermediate base station 400 receives the data and replies with an acknowledgment signal (Rep) to the dual-satellite backup controllable bidirectional communication base station 500. Next, the buoyancy self-balancing adjustment intermediate base station 400 sends data (Data) to the bottom-level base station 300; the bottom-level base station 300 replies with an acknowledgment signal (Rep). Finally, the bottom-level base station 300 continues to send data to the AUV motion monitoring node 200; the AUV motion monitoring node 200 replies with an acknowledgment signal (Rep); the bottom-level base station 300 then sends an acknowledgment character (ACK) to the AUV motion monitoring node 200, indicating that the data transmission has been completed. This ultimately enables the shore-based receiving system 600 to control the AUV motion monitoring node 200.

Claims

1. A data transmission method for a heterogeneous communication cascaded remotely controllable seabed observation system, characterized in that: The heterogeneous communication cascaded remote controllable seabed observation system includes distributed monitoring nodes (100), AUV mobile monitoring nodes (200), relay transmission modules, and shore-based receiving systems (600); the relay transmission modules include a bottom base station (300), a buoyancy self-balancing intermediate base station (400), and a dual-satellite backup controllable two-way communication base station (500) connected from bottom to top by a zero-buoyancy coaxial cable (700); the dual-satellite backup controllable two-way communication base station (500) is installed in the mooring. The relay transmission module can control itself to rise and fall; The relay transmission module has two working modes: seabed communication mode and surface communication mode. In seabed communication mode, the relay transmission module submerges to a specified depth below the sea surface, enabling the buoyancy self-balancing intermediate base station (400) to communicate with the distributed monitoring node (100), and the bottom base station (300) to communicate with the AUV mobile monitoring node (200). In surface communication mode, the relay transmission module rises to the sea surface and communicates with the shore-based receiving system (600) via the Tiantong satellite and / or Beidou satellite, with a dual-satellite backup controllable bidirectional communication base station (500). The zero-buoyancy coaxial cable (700) is an optoelectronic composite cable. The buoyancy self-balancing intermediate base station (400) communicates with the distributed monitoring node (100) via underwater acoustic communication. The bottom base station (300) communicates with the cruising AUV mobile monitoring node (200) via laser communication. The data transmission method process is as follows: When the relay transmission module needs to communicate with the distributed monitoring node (100) and the AUV mobile monitoring node (200), the relay transmission module enters the seabed communication mode and dives to the preset depth; the data received by the bottom base station (300) is sent to the buoyancy self-balancing adjustment intermediate base station (400) through the zero buoyancy coaxial cable (700); the data received by the buoyancy self-balancing adjustment intermediate base station (400) is sent to the dual-satellite backup controllable bidirectional communication base station (500) for storage through the zero buoyancy coaxial cable (700); When the relay transmission module communicates with the shore-based receiving system (600), the relay transmission module enters the sea surface communication mode and floats to the water surface. The dual-satellite backup controllable bidirectional communication base station (500) communicates with the shore-based receiving system (600) through Tiantong satellite or Beidou satellite. The communication process via the zero-buoyancy coaxial cable (700) is as follows: Step 1: Evaluate the two channels of the communication link using a channel evaluation model; the two channels are the optical transmission channel and the electrical transmission channel. Step 2: Channel allocation; The scores of optical and electrical transmission channels are compared; the channel with the higher score is selected as the main channel, and the channel with the lower score is selected as the secondary channel. Step 3: Determine if the data to be transmitted is a retransmitted data packet; if yes, skip step 4 and proceed directly to step 5; otherwise, execute steps 4 and 5 in sequence; retransmitted data packets are data that failed to be sent. Step 4: Data packet length allocation and data packet segmentation; The data to be transmitted is divided into a main line transmission part and a secondary line transmission part and packaged to obtain main line data packets and secondary line data packets; The data importance of the primary data packet is higher than that of the secondary data packet; Step 5: Data transmission occurs between the main line and the secondary line; The mainline transmits two parts in a single data transmission: the first part includes the mainline data packet's data content, number, channel quality, data packet length, and CRC checksum; the second part includes the secondaryline data packet's number, channel quality, data packet length, and data CRC checksum. The secondary line transmits the following information in a single data transmission: the data content, number, channel quality, data packet length, and CRC checksum of the secondary line data packet.

2. The data transmission method according to claim 1, characterized in that: The distributed monitoring node (100) is equipped with a first underwater acoustic communication device, a node processor, a pressure sensor, an underwater positioning module, a turbidity sensor, and an underwater camera unit; the pressure sensor is used to locate water depth data; the underwater positioning module is used to acquire and confirm the location of the distributed monitoring node (100); the turbidity sensor is used to collect concentration data of the seabed plume; the underwater camera unit is used to acquire image data of the seabed environment; the first underwater acoustic communication device communicates with a second underwater acoustic communication device set in the buoyancy self-balancing adjustment intermediate base station (400).

3. The data transmission method according to claim 1, characterized in that: The dual-satellite backup controllable bidirectional communication base station (500) includes a first EDSL communication circuit, a communication processing circuit, a Tiantong communication module, and a Beidou communication module; the first EDSL communication circuit is connected to the second EDSL communication circuit of the buoyancy self-balancing intermediate base station (400) via a zero-buoyancy coaxial cable (700); the communication processing circuit receives the communication data output by the second EDSL communication circuit and organizes the communication data into communication data packets; the data output interface of the communication processing circuit is connected to the Tiantong communication module and the Beidou communication module; when the relay transmission module is in the sea surface communication mode, the Tiantong communication module communicates with the Tiantong satellite; the Beidou communication module communicates with the Beidou satellite. The shore-based receiving system (600) includes a satellite signal receiving module, a processor, and a host computer; the satellite signal receiving module includes a satellite signal receiver and a data conversion module; the satellite signal receiver communicates with BeiDou satellites and TianTong satellites; the satellite signal receiver is connected to the data conversion module; the data conversion module is used to parse the satellite signal and send it to the processor, and to modulate the signal transmitted by the processor into a satellite signal; the processor is used to receive the signal processed by the data conversion module and upload it to the host computer, and to send the host computer signal to the data conversion module.

4. The data transmission method according to claim 1, characterized in that: The buoyancy self-balancing intermediate base station (400) includes a second EDSL communication circuit, a third EDSL communication circuit, a second underwater acoustic communication device, a first system scheduling gateway, and a buoyancy lift-up control circuit; the second EDSL communication circuit is connected to the first EDSL communication circuit of the dual-satellite backup controllable bidirectional communication base station (500) via a zero-buoyancy coaxial cable (700); the third EDSL communication circuit is connected to the fourth EDSL communication circuit of the bottom base station (300) via a zero-buoyancy coaxial cable (700); the second underwater acoustic communication device is connected to the second central processing circuit and communicates with the distributed monitoring node (100); The first system dispatch gateway connects the second EDSL communication circuit, the third EDSL communication circuit, the second underwater acoustic communication device, and the snorkeling and buoyancy control circuit; the snorkeling and buoyancy control circuit includes a second central processing circuit, a motor driver, and a motor; the motor controls the relay transmission module to rise or sink.

5. The data transmission method according to claim 1, characterized in that: The channel evaluation model adopts a neural network model; the input layer neurons of the channel evaluation model are normalized values ​​of channel quality, channel occupancy, data volume and data priority for each channel segment; the hidden layer of the channel evaluation model is a fully connected layer that connects the neurons of multiple input layers and uses the sigmoid function as the activation function; the output layer neurons of the channel evaluation model are the normalized results of each channel score.

6. The data transmission method according to claim 1, characterized in that: In step three, whether a data packet transmission failure has occurred is determined by whether the data receiving end of the communication sends back a retransmission signal.

7. The data transmission method according to claim 1, characterized in that: In step four, the data lengths of the mainline and secondaryline data packets are determined based on the scores given to the mainline and secondaryline data packets. i : ； Where i = 1, 2; This is a floor function, with the unit being bytes; , These are the data packet length values ​​for the main line and the secondary line, respectively. , These are the ratings for the main storyline and the sub-storyline, respectively. For conversion constants; Based on the data length of the mainline data packet and the secondaryline data packet i The transmitted data is divided into mainline data packets and secondaryline data packets.

8. The data transmission method according to claim 1, characterized in that: The specific process of communication between the dual-satellite backup controllable bidirectional communication base station (500) and the shore-based receiving system (600) is as follows: (1) Priority management is performed on the data to be transmitted; the priority is divided into four levels; the data signals are transmitted in order of priority from high to low. (2) Before transmitting data, channel quality detection is performed on the BeiDou satellite link and the TianTong satellite link respectively to obtain the remaining bandwidth value and channel quality value of the transmission channel of the BeiDou satellite link and the TianTong satellite link respectively; (3) When the amount of data transmitted is less than the short message length of the BeiDou satellite link, and the channel quality of the BeiDou satellite link is stable, the BeiDou satellite link shall be used for transmission; When the data volume exceeds the short message length of the BeiDou satellite link, the two satellite links are used together for dynamic data transmission. The process is as follows: the data packet length is dynamically divided based on the remaining bandwidth and channel quality values ​​of the BeiDou and TianTong satellite links. Number the data packet and complete the submission; data packet length The expression is: ； Where i = 1, 2; This is a floor function; , These are the data packet length values ​​for the BeiDou satellite link and the TianTong satellite link, respectively. , These are the remaining bandwidth values ​​of the transmission channels for the BeiDou satellite link and the TianTong satellite link, respectively. , These are the total bandwidth values ​​of the transmission channels for the BeiDou satellite link and the TianTong satellite link, respectively. , These are the channel quality values ​​for the BeiDou satellite link and the TianTong satellite link, respectively. , These are the maximum channel quality values ​​for the BeiDou satellite link and the TianTong satellite link, respectively. , To assign importance weights to the remaining bandwidth of the transmission channel and the channel quality, ; , These are the conversion constants for the BeiDou satellite link and the TianTong satellite link, respectively. (4) Data transmission; When the two satellite links are called together to perform dynamic data transmission, the Beidou satellite link transmits two parts of data; the first part of the data is the data packet allocated to the Beidou satellite link for transmission; the second part of the data is the verification information of the data packet allocated to the Tiantong satellite link for transmission, including the data packet number, data packet length data, Tiantong satellite module channel quality value and CRC check code; (5) The shore-based receiving system receives data transmitted by the Beidou satellite link and / or the Tiantong satellite link. According to the verification information in the data transmitted by the Beidou satellite link, it combines and verifies all the data. It returns the label of the data packet with the verification error and requests the dual-satellite backup controllable bidirectional communication base station (500) to retransmit the data packet with the error.

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