Unmanned ship water depth data acquisition and transmission method and system with position association and redundancy storage functions

Abstract

The invention provides an unmanned ship water depth data acquisition and transmission method and system with position association and redundancy storage functions, and belongs to the technical field of unmanned ship water depth data transmission, and the system comprises an RTK positioning system, a depth sounding sensor, a data fusion system, an unmanned ship autopilot, a USB flash disk memory, a ground station QGC, a data transmission module interface and a shore-based controller. By integrating the self-driving instrument module, the GPS positioning unit and the depth sensor, real-time fusion of water depth data, the current position and course information is achieved. Meanwhile, wireless communication modes such as LoRa and the like are adopted, and the fused data are synchronously sent to a shore-based controller for local display and redundant storage. Even under the condition of power failure or equipment abnormity, the recorded data can still be completely stored at the shore-based controller end, the reliability of data storage is improved, and the influence of a complex environment can be better overcome through the unmanned aerial vehicle serving as a temporary server and a high-frequency sound wave communication mode.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned vessel water depth data transmission, and in particular to an unmanned vessel water depth data acquisition and transmission method and system with position association and redundant storage functions. Background Art

[0002] Traditional unmanned vessel depth sounding systems usually only obtain water depth data through a single sensor, lacking real-time correlation with geographic location and heading information, making it difficult for operators to intuitively interpret water depth changes in a map environment. At the same time, existing systems mostly use the MAVLink protocol to transmit water depth data to the QGroundControl (QGC) ground station for real-time display. However, in the event of network instability or equipment failure (such as power outages or freezes), data transmission may be interrupted, resulting in the loss of historical data and affecting the integrity of the surveying and mapping mission. Current systems generally lack effective redundant storage methods and cannot ensure the complete preservation of data when data transmission is interrupted, increasing the risk of data loss.

[0003] The depth measurement and data transmission of unmanned vessels have initially formed a set of common technical paths in industry applications: (1) Using sensors to measure depth: The output depth value is directly provided to the control system, ground station (QGroundControl, MissionPlanner, etc.), or storage device. This type of solution usually regards the depth data as an independent parameter; it lacks synchronous integration with position and heading data, thereby reducing the spatial interpretability and application depth of the overall data. (2) The depth sensor relies on a single communication protocol for transmission: The common practice in the industry is to transmit and present the depth data to the QGC software through protocols such as MAVLink, NMEA0183, RS-232 / RS-485 to achieve remote monitoring and basic recording. However, the data acquisition and transmission link is still prone to instability due to factors such as environmental interference, distance restrictions, and electromagnetic shielding. Once the transmission is blocked or the link is interrupted, the QGC side often lacks an alternative path to obtain the corresponding data, which affects the continuity of real-time monitoring and subsequent analysis. (3) Data storage: Most current systems concentrate data storage and management functions on a single storage medium inside the ground control terminal or unmanned vessel. This means that if the power supply of the unmanned vessel is interrupted, the main control system crashes, the sensor malfunctions, or the communication link is interrupted, some or even all of the bathymetric data may not be backed up and saved in time, resulting in the irreversible loss of key surveying and mapping data, which will bring great difficulties to subsequent analysis. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and system for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions, so as to solve the technical problems mentioned in the background technology.

[0005] The system uses three independent serial port channels to achieve synchronous acquisition and analysis of multi-source data. During the data acquisition and analysis process, the system introduces a multi-layer logic analysis and data fusion mechanism. When receiving instructions from shore-based controllers or unmanned vessels, the system can flexibly adjust parameters and change status.

[0006] Depth sounder → (serial port 1) → buffer 1, RTK positioning → (serial port 2) → buffer 2 Autopilot & control commands → (serial port 3) → command processing module.

[0007] Data parsing and preprocessing,The parsing module extracts NMEA fields from buffer 1 / 2 → removes outliers → converts units.

[0008] Time synchronization and data fusion, check timestamp → match bathymetric data and positioning data → generate fused data records.

[0009] Data packaging and transmission: Data frame generation → Add checksum and frame number → Send to autopilot (serial port 3). Autopilot → Wireless module → Shore-based control / ground station.

[0010] Redundant storage: data is stored in a USB flash drive and sent to QGC for storage in txt format.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0012] A method for collecting and transmitting water depth data from an unmanned vessel with position association and redundant storage functions, the method comprising the following steps:

[0013] Step 1: Data acquisition: obtain the depth data of the echo sounder and the positioning information of the RTK positioning device through the serial port, fuse the acquired data, and then transmit it to the unmanned vessel autopilot to realize the sending of fused data and the reception of commands;

[0014] Step 2: Analyze and preprocess the data, parse the format of the bathymetric and positioning messages, extract key fields, convert the extracted latitude and longitude information from degree-minute format, filter out abnormal or invalid data, and perform interpolation repair as needed;

[0015] Step 3: Time synchronization and data fusion: synchronize and match data based on timestamps, bind bathymetric data and positioning data with similar time periods to obtain a fused data structure containing position and depth. Data that exceeds the time synchronization threshold is processed by waiting, discarding, or interpolating.

[0016] Step 4: Data packaging and transmission: The fused data is packaged according to the set protocol format, with frame header, frame sequence number, and checksum added. The data is then sent to the unmanned vessel autopilot through the serial port. The autopilot is then transmitted to the ground station and shore-based controller via the wireless link. The fused data is stored and displayed on the ground station and shore-based controller to achieve real-time monitoring.

[0017] Step 5: Redundant storage and fault response. Real-time data or periodic data are packaged and stored locally using storage media on the unmanned vessel. Data received at the shore-based control end is also redundantly saved to prevent data loss due to link interruption or equipment failure. When the network is restored or the unmanned vessel goes ashore again, the data on the storage medium is collated, merged, or updated with the shore-based data.

[0018] Furthermore, the specific process of step 1 is:

[0019] Step 1.1: Read the echo sounder data. Monitor the NMEA 0183 format message output by the echo sounder through the first serial port 1. The message includes three water depth values and calibration data. Each time a message is received, it is placed in the echo sounder data ring buffer for subsequent analysis.

[0020] Step 1.2: Read RTK positioning data. Monitor the NMEA 0183 messages output by the RTK positioning device through serial port 2. Each received message is placed in the positioning data ring buffer for subsequent analysis.

[0021] Step 1.3: The autopilot serial port interface communicates with the unmanned vessel autopilot through serial port 3 and receives control commands from the autopilot. The control commands include starting sampling, stopping sampling, and changing the transmission frequency. The fused water depth data and positioning data are packaged and transmitted to the autopilot.

[0022] Furthermore, the specific process of step 2 is:

[0023] Step 2.1: Split the NMEA message into independent fields using commas as delimiters or regular expressions. For GGA messages, extract the time, latitude, longitude, positioning quality, number of satellites, and altitude fields. For RMC messages, extract the time, positioning status, latitude, longitude, speed, heading, and date fields. For SDDBT messages, extract the water depth value and its unit.

[0024] Step 2.2: Convert units and formats. Convert the latitude and longitude in degree format to decimal degree format, and convert the water depth value to meter.

[0025] Step 2.3: Processing of outliers and missing values: negative water depth values are judged as abnormal. If outliers occur, they are marked or filtered. Missing water depth values are interpolated or discarded.

[0026] Furthermore, the specific process of step 3 is:

[0027] Step 3.1: Time synchronization: Establish a unified time base, using the timestamp provided by RTK as the standard. Compare the timestamps of the water depth data with those of the positioning data. If the time difference between the two is within the threshold of ±0.1 seconds, they are considered to correspond to the same time period and can be directly integrated. If it exceeds the threshold, the following method is used for processing: Interpolation strategy: When the interval between the two is greater than the set value, linear interpolation is performed using the aligned data before and after, and the mean water depth or position at the intermediate time is estimated;

[0028] Step 3.2: Data fusion, bind the time-aligned water depth values with latitude and longitude, altitude and heading to form a new fused data structure, namely timestamp, latitude, longitude, water depth, heading and speed.

[0029] Furthermore, the specific process of step 4 is:

[0030] Step 4.1: Data frame structure design. After fusion, assemble the data frame, data content, fixed word, frame sequence number, and checksum field according to the custom protocol. The frame header has a fixed byte 0xAA55, which is used to mark the start of the data. The data content includes timestamp, latitude, longitude, water depth, heading, and speed. The fixed byte and frame sequence number facilitate the receiver to detect packet loss or disorder. The checksum field is the F* checksum to ensure that the data has not been tampered with or damaged.

[0031] Step 4.2: Serial port parameters and sending strategy, select the baud rate that matches the unmanned vessel autopilot. To ensure real-time and stability, use batch packaging to package every N data into a data block and send them together to reduce transmission overhead.

[0032] Step 4.3: Processing at the receiving end. After the autopilot receives the data, it forwards the data to the ground station and shore-based controller via the built-in or external wireless communication module. The ground station and shore-based controller display the ship's position, heading, and water depth curve in real time, and store the data locally.

[0033] Furthermore, the specific process of step 5 is:

[0034] Step 5.1: Local storage on a USB flash drive. After the data is generated or processed, the UAV will periodically write the data to the USB flash drive and store it in segments. Every 10 minutes or when the data volume reaches a threshold, a new file will be created to prevent a single file from exceeding the set value. Verification and breakpoint rewriting will be performed. After writing is completed, the file will be verified. If the power is lost during the process, the file will be checked and rewritten after the next boot.

[0035] Step 5.2: Shore-based redundant storage. After receiving the data, the shore-based controller will write it to the USB flash drive synchronously to form another backup, forming a primary and backup storage mode with the QGC ground station to prevent data loss or errors due to the failure of a single device.

[0036] Furthermore, in step 5, a high-frequency acoustic wave transmitter is provided on the unmanned ship. When the unmanned ship cannot communicate with the ground station and the shore-based controller, the high-frequency acoustic wave transmitter on the unmanned ship starts to seek communication. A relay drone is provided on the ground station, and a high-frequency acoustic wave receiver is provided on the relay drone. After the ground station and the shore-based controller cannot communicate with the unmanned ship, the relay drone is ejected and flies to the latitude and longitude position of the unmanned ship last received by the ground station, and establishes high-frequency acoustic wave communication with the unmanned ship until the unmanned ship resumes communication with the ground station and the shore-based controller, or the staff determines the specific location of the unmanned ship and manually controls the relay drone to fly back, effectively avoiding the problem of the unmanned ship losing contact and being difficult to find.

[0037] A system for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions includes an RTK positioning system, a depth sounding sensor, a data fusion system, an unmanned vessel autopilot, a USB flash drive storage device, a ground station QGC, a data transmission module interface, and a shore-based controller. The RTK positioning system and the depth sounding sensor are both connected to the data fusion system, the data fusion system is connected to the unmanned vessel autopilot, the USB flash drive storage device is connected to the unmanned vessel autopilot, the ground station QGC is wirelessly connected to the unmanned vessel autopilot, the data transmission module interface is wirelessly connected to the unmanned vessel autopilot, and the shore-based controller is connected to the data transmission module interface.

[0038] Furthermore, the process of implementing process control and event response mechanism within the system is as follows:

[0039] (1) The RTK data reading subtask detects and parses the NMEA message after initializing the serial port, injects the updated latitude, longitude and time information into the circular buffer, and can be called by the data fusion module at any time;

[0040] (2) The water depth data parsing subtask then decodes the SDDBT message in real time and writes the instantaneous water depth value into the ring buffer, waiting for fusion processing together with the positioning data;

[0041] (3) The data fusion and transmission subtask periodically retrieves the ring buffer data. Once the associated water depth value and position data are found, the fusion and data packaging process is triggered, and the packaged data frame is sent to the unmanned ship and the LORA wireless link for external output;

[0042] The specific process of system parameter adjustment and status change is as follows:

[0043] (1) When receiving the sampling start command, the system starts the data continuous recording and transmission process;

[0044] (2) After receiving instructions such as stopping sampling or changing the transmission frequency, the system adjusts the corresponding subtask operating status and data writing strategy according to the instruction content.

[0045] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0046] This invention integrates an autopilot module, a GPS positioning unit, and a depth sensor to achieve real-time fusion of water depth data with current position and heading information. Furthermore, wireless communication methods such as LoRa are used to synchronously transmit the fused data to a shore-based controller for local display and redundant storage. Even in the event of a power outage or equipment anomaly, the recorded data remains intact on the shore-based controller, improving data storage reliability. Furthermore, by using the drone as a temporary server and high-frequency acoustic communication, the system can better overcome the influence of complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a system block diagram of the present invention. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and by way of preferred embodiments. However, it should be noted that many of the details listed in this specification are merely provided to help the reader gain a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be practiced even without these specific details.

[0049] A method for collecting and transmitting water depth data from an unmanned vessel with position association and redundant storage functions comprises the following steps:

[0050] Step 1: Multi-source data collection

[0051] Serial port 1 is used to obtain depth data from the echo sounder (such as SDDBT messages). Serial port 2 is used to obtain positioning information from the RTK positioning device (such as GGA and RMC messages). Serial port 3 is used to connect to the unmanned vessel autopilot to send fused data and receive commands.

[0052] 1.1 Depth Sounder Data Reading

[0053] Monitor the NMEA0183 format message (SDDBT, water depth value 1, water depth value 2, water depth value 3, F* checksum) output by the depth sounder through serial port 1.

[0054] Each time a message is received, it is placed in the sounding data ring buffer for subsequent analysis.

[0055] 1.2RTK positioning data reading

[0056] Monitor the NMEA 0183 messages (such as GGA, RMC, etc.) output by the RTK positioning device through serial port 2.

[0057] Each time a message is received, it is placed in the positioning data ring buffer for subsequent analysis.

[0058] 1.3 Autopilot serial port interface

[0059] Communicate with the UAV autopilot through serial port 3: Receive control commands or requests from the autopilot (such as starting sampling, stopping sampling, changing transmission frequency, etc.). Package the fused water depth data and positioning data and transmit them to the autopilot.

[0060] Step 2: Data parsing and preprocessing

[0061] Parse the bathymetric and positioning messages to extract key fields (such as timestamp, latitude, longitude, and water depth). Convert the extracted longitude and latitude information from degree-minute format to decimal-degree format (if necessary). Filter out abnormal or invalid data and perform interpolation repairs when necessary.

[0062] 2.1 Message Field Splitting

[0063] Split NMEA messages into separate fields using commas as delimiters or other suitable methods (regular expressions, etc.). For GGA messages, extract fields such as time, latitude, longitude, position quality, number of satellites, and altitude. For RMC messages, extract fields such as time, position status, latitude, longitude, speed, heading, and date. For SDDBT messages, extract water depth and its unit.

[0064] 2.2 Unit and format conversion

[0065] Convert longitude and latitude in degree format to decimal degree format. If the water depth value is uniformly converted to meters (m).

[0066] 2.3 Handling of outliers and missing values.

[0067] When the water depth value is negative, an abnormality is judged. If an abnormal value occurs, it is marked or filtered; missing water depth values can be interpolated or discarded depending on the situation.

[0068] Step 3: Time synchronization and data fusion

[0069] Synchronize and match multi-source data based on timestamps. Combine bathymetric and positioning data with similar time signatures (within a set threshold) to create a fused data structure containing both position and depth. Data outside the time synchronization threshold can be processed by waiting, discarding, or interpolating.

[0070] 3.1 Time Synchronization

[0071] Establish a unified time base (based on the timestamp provided by RTK). Compare the timestamps of the depth data with the positioning data. If the time difference between the two is within the threshold of ±0.1 seconds, they are considered to correspond to the same time period and can be directly fused.

[0072] If the threshold is exceeded, the following processing is performed:

[0073] Interpolation strategy: When the gap between the two is too large, linear interpolation is performed using the aligned data before and after, and the mean of the water depth or position at the intermediate moment is estimated.

[0074] 3.2 Data Fusion

[0075] The time-aligned water depth values are bound to latitude and longitude, altitude, heading, etc. to form a new fusion data structure, namely timestamp, latitude, longitude, water depth, heading and speed.

[0076] Step 4: Data Packaging and Transmission

[0077] The fused data is packaged according to the specified protocol format, with a frame header, frame sequence number, and checksum added. It is then sent to the UAV's autopilot via serial port 3. The autopilot's wireless link then transmits it to the ground station and shore-based controller. The fused data is stored and displayed on the ground station and shore-based controller, enabling real-time monitoring.

[0078] 4.1 Data frame structure design

[0079] After fusion, data frames are assembled according to a custom protocol: a frame header (fixed byte: 0xAA55) to mark the start of data; data content (timestamp, latitude, longitude, water depth, heading, speed, etc.) (fixed byte); a frame sequence number to facilitate the receiver's detection of packet loss or disorder; and a checksum field (F* checksum) to ensure that the data has not been tampered with or damaged.

[0080] 4.2 Serial port parameters and sending strategy

[0081] Select a baud rate that matches the unmanned vessel's autopilot (e.g., 115200 bps). To ensure real-time and stability, use batch packaging to package every N data items into a data block and send them together to reduce transmission overhead.

[0082] 4.3 Receiver Processing

[0083] After receiving the data, the autopilot forwards it to a ground station and shore-based controller via a built-in or external wireless communication module. These stations and shore-based controllers display the vessel's position, heading, and water depth curves in real time and store the data locally.

[0084] Step 5: Redundant storage and fault response

[0085] The unmanned vessel uses a USB flash drive or other storage medium to store real-time or periodically packaged data locally. The shore-based control system also stores received data redundantly to prevent data loss due to link interruptions or equipment failures. When the network is restored or the unmanned vessel returns to shore, the USB flash drive data can be collated, merged, or updated with the shore-based data.

[0086] 5.1U disk local storage

[0087] After data generation or processing is complete, the UAV periodically writes the data to a USB flash drive. Segmented storage: A new file is created every 10 minutes or when the data volume reaches a threshold to prevent a single file from becoming too large. Verification and breakpoint resumption: The file is verified after writing is complete. If power is lost midway, the file can be checked and resumed after the next reboot.

[0088] 5.2 Shore-based redundant storage

[0089] After receiving the data, the shore-based controller writes it to the USB flash drive to form another backup. Together with the QGC ground station, it forms a primary and backup storage mode to prevent data loss or errors due to the failure of a single device.

[0090] like Figure 1 As shown, a system for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions includes an RTK positioning system, a depth sounding sensor, a data fusion system, an unmanned vessel autopilot, a USB flash drive storage, a ground station QGC, a data transmission module interface, and a shore-based controller. The RTK positioning system and the depth sounding sensor are both connected to the data fusion system, the data fusion system is connected to the unmanned vessel autopilot, the USB flash drive storage is connected to the unmanned vessel autopilot, the ground station QGC is wirelessly connected to the unmanned vessel autopilot, the data transmission module interface is wirelessly connected to the unmanned vessel autopilot, and the shore-based controller is connected to the data transmission module interface.

[0091] The unmanned ship is equipped with a high-frequency acoustic wave transmitter. When the unmanned ship cannot communicate with the ground station and the shore-based controller, the high-frequency acoustic wave transmitter on the unmanned ship starts to seek communication. The ground station is equipped with a relay drone, and the relay drone is equipped with a high-frequency acoustic wave receiver. After the ground station and the shore-based controller cannot communicate with the unmanned ship, the relay drone is ejected and flies to the latitude and longitude position of the unmanned ship last received by the ground station, and establishes high-frequency acoustic wave communication with the unmanned ship until the unmanned ship resumes communication with the ground station and the shore-based controller, or the staff determines the specific location of the unmanned ship and manually controls the relay drone to fly back, effectively avoiding the problem of the unmanned ship losing contact and being difficult to find.

[0092] If communication cannot be established even when launching the drone, it is determined that the machinery has failed and cannot work.

[0093] The system achieves synchronous acquisition and analysis of multi-source data through three independent serial port channels:

[0094] (1) Serial port 1 is used to communicate with the water depth measuring instrument, and digitally collect and analyze the SDDBT message it outputs to obtain real-time water depth data (change in water depth value per unit time).

[0095] (2) Serial port 2 is used to communicate with the RTK positioning device, digitally collect and analyze NMEA standard format messages such as RMC and GGA, obtain real-time latitude, longitude and elevation information, and assign spatial position and time reference to water depth data.

[0096] (3) Serial port 3 is directly connected to the serial port interface of the unmanned vessel control terminal, transmitting the processed and geographically associated water depth data to the unmanned vessel, realizing local data integration and status sharing. This serial port also receives control commands or communication feedback information from the unmanned vessel.

[0097] During the data acquisition and analysis process, the system introduces a multi-layer logic analysis and data fusion mechanism as follows:

[0098] (1) The water depth data and RTK positioning data are integrated in real time, and the water depth values at the same timestamp are bound to the geographic location parameters, so that the operator can intuitively interpret the underwater terrain changes in a graphical manner during later data analysis or real-time monitoring.

[0099] (2) The data fusion device synchronizes and calibrates the data of serial port 1 and serial port 2 in the logic controller, and integrates the water depth data and longitude and latitude information into a target data frame with geographic reference coordinates according to the set rules.

[0100] The wireless communication link uses the LORA module to achieve remote data transmission and monitoring process as follows:

[0101] (1) After the fusion is completed, the system sends the water depth and positioning data to the shore-based controller through the LORA link. After receiving the signal, the shore-based end can display and monitor the hull position, water depth parameters and communication status in real time in the graphical interface.

[0102] (2) LORA communication has the advantages of low power consumption, anti-interference and long-distance transmission, and can maintain the stability and continuity of the data link even in relatively complex water environments.

[0103] The redundant data storage mechanism ensures data security and traceability. The process is as follows:

[0104] (1) The system is equipped with a USB interface for connecting to a USB storage medium and writing the real-time or periodically acquired fusion data to the USB disk.

[0105] (2) When network interruption, equipment abnormality (such as power outage, system crash) or unstable transmission occurs, even if the shore-based system cannot obtain all data in time, the records in the USB flash drive can still ensure the complete preservation of the surveying and mapping data. The operator can then export the data from the USB flash drive for subsequent manual analysis, correction or tracing of underwater surveying and mapping results.

[0106] To ensure the orderliness of data processing and execution logic, the process of implementing process control and event response mechanism within the system is as follows:

[0107] (1) The RTK data reading subtask detects and parses the NMEA message after initializing the serial port, and injects the updated latitude, longitude and time information into the circular buffer, which can be called by the data fusion module at any time.

[0108] (2) The water depth data parsing subtask decodes the SDDBT message in real time in a similar way and writes the instantaneous water depth value into the ring buffer, waiting for fusion processing together with the positioning data.

[0109] (3) The data fusion and transmission subtask periodically retrieves the ring buffer data. Once the associated water depth value and position data are found, the fusion and data packaging process is triggered, and the packaged data frame is sent to the unmanned ship and the LORA wireless link for external output.

[0110] When receiving instructions from a shore-based controller or unmanned vessel, the system can flexibly adjust parameters and change status in the following process:

[0111] (1) When receiving the sampling start command, the system starts the data continuous recording and transmission process.

[0112] (2) After receiving instructions such as stopping sampling or changing the transmission frequency, the system adjusts the corresponding subtask operating status and data writing strategy according to the instruction content.

[0113] Matters not covered by the present invention are known technologies.

[0114] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. An unmanned vessel depth data acquisition and transmission method with position association and redundant storage functions, characterized by: The method comprises the following steps: Step 1: Data acquisition: obtain the depth data of the echo sounder and the positioning information of the RTK positioning device through the serial port, fuse the acquired data, and then transmit it to the unmanned vessel autopilot to realize the sending of fused data and the reception of commands; Step 2: Analyze and preprocess the data, parse the format of the bathymetric and positioning messages, extract key fields, convert the extracted latitude and longitude information from degree-minute format, filter out abnormal or invalid data, and perform interpolation repair as needed; Step 3: Time synchronization and data fusion: synchronize and match data based on timestamps, bind bathymetric data and positioning data with similar time periods to obtain a fused data structure containing position and depth. Data that exceeds the time synchronization threshold is processed by waiting, discarding, or interpolating. Step 4: Data packaging and transmission: The fused data is packaged according to the set protocol format, with frame header, frame sequence number, and checksum added. The data is then sent to the unmanned vessel autopilot through the serial port. The autopilot is then transmitted to the ground station and shore-based controller via the wireless link. The fused data is stored and displayed on the ground station and shore-based controller to achieve real-time monitoring. Step 5: Redundant storage and fault response. Real-time data or periodic data are packaged and stored locally using storage media on the unmanned vessel. Data received at the shore-based control end is also redundantly saved to prevent data loss due to link interruption or equipment failure. When the network is restored or the unmanned vessel goes ashore again, the data on the storage medium is collated, merged, or updated with the shore-based data.

2. The method for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions according to claim 1 is characterized in that: The specific process of step 1 is: Step 1.1: Read the echo sounder data. Monitor the NMEA 0183 format message output by the echo sounder through the first serial port 1. The message includes three water depth values and calibration data. Each time a message is received, it is placed in the echo sounder data ring buffer for subsequent analysis. Step 1.2: Read RTK positioning data. Monitor the NMEA 0183 messages output by the RTK positioning device through serial port 2. Each received message is placed in the positioning data ring buffer for subsequent analysis. Step 1.3: The autopilot serial port interface communicates with the unmanned vessel autopilot through serial port 3 and receives control commands from the autopilot. The control commands include starting sampling, stopping sampling, and changing the transmission frequency. The fused water depth data and positioning data are packaged and transmitted to the autopilot.

3. The method for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions according to claim 1 is characterized in that: The specific process of step 2 is: Step 2.1: Split the NMEA message into independent fields using commas as delimiters or regular expressions. For GGA messages, extract the time, latitude, longitude, positioning quality, number of satellites, and altitude fields. For RMC messages, extract the time, positioning status, latitude, longitude, speed, heading, and date fields. For SDDBT messages, extract the water depth value and its unit. Step 2.2: Convert units and formats. Convert the latitude and longitude in degree format to decimal degree format, and convert the water depth value to meter. Step 2.3: Processing of outliers and missing values: negative water depth values are judged as abnormal. If outliers occur, they are marked or filtered. Missing water depth values are interpolated or discarded.

4. The method and system for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions according to claim 1, characterized in that: The specific process of step 3 is: Step 3.1: Time synchronization: Establish a unified time base, using the timestamp provided by RTK as the standard. Compare the timestamps of the water depth data with those of the positioning data. If the time difference between the two is within the threshold of ±0.1 seconds, they are considered to correspond to the same time period and can be directly integrated. If it exceeds the threshold, the following method is used for processing: Interpolation strategy: When the interval between the two is greater than the set value, linear interpolation is performed using the aligned data before and after, and the mean water depth or position at the intermediate time is estimated; Step 3.2: Data fusion, bind the time-aligned water depth values with latitude and longitude, altitude and heading to form a new fused data structure, namely timestamp, latitude, longitude, water depth, heading and speed.

5. The method for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions according to claim 1 is characterized in that: The specific process of step 4 is: Step 4.1: Data frame structure design. After fusion, assemble the data frame, data content, fixed word, frame sequence number, and checksum field according to the custom protocol. The frame header has a fixed byte 0xAA55, which is used to mark the start of the data. The data content includes timestamp, latitude, longitude, water depth, heading, and speed. The fixed byte and frame sequence number facilitate the receiver to detect packet loss or disorder. The checksum field is the F* checksum to ensure that the data has not been tampered with or damaged. Step 4.2: Serial port parameters and sending strategy, select the baud rate that matches the unmanned vessel autopilot. To ensure real-time and stability, use batch packaging to package every N data into a data block and send them together to reduce transmission overhead. Step 4.3: Processing at the receiving end. After the autopilot receives the data, it forwards the data to the ground station and shore-based controller via the built-in or external wireless communication module. The ground station and shore-based controller display the ship's position, heading, and water depth curve in real time, and store the data locally.

6. The method for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions according to claim 1 is characterized in that: The specific process of step 5 is: Step 5.1: Local storage on a USB flash drive. After the data is generated or processed, the UAV will periodically write the data to the USB flash drive and store it in segments. Every 10 minutes or when the data volume reaches a threshold, a new file will be created to prevent a single file from exceeding the set value. Verification and breakpoint rewriting will be performed. After writing is completed, the file will be verified. If the power is lost during the process, the file will be checked and rewritten after the next boot. Step 5.2: Shore-based redundant storage. After receiving the data, the shore-based controller will write it to the USB flash drive synchronously to form another backup, forming a primary and backup storage mode with the QGC ground station to prevent data loss or errors due to the failure of a single device.

7. The method for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions according to claim 1 is characterized in that: In step 5, a high-frequency acoustic wave transmitter is provided on the unmanned ship. When the unmanned ship fails to communicate with the ground station and the shore-based controller, the high-frequency acoustic wave transmitter on the unmanned ship starts to seek communication. A relay drone is provided on the ground station, and a high-frequency acoustic wave receiver is provided on the relay drone. After the ground station and the shore-based controller fail to communicate with the unmanned ship, the relay drone is ejected and flies to the latitude and longitude position of the unmanned ship last received by the ground station, and establishes high-frequency acoustic wave communication with the unmanned ship until the unmanned ship resumes communication with the ground station and the shore-based controller, or the staff determines the specific location of the unmanned ship and manually controls the relay drone to fly back, effectively avoiding the problem of the unmanned ship losing contact and being difficult to find.

8. The system for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions according to any one of claims 1 to 7, characterized in that: It includes an RTK positioning system, a depth sounding sensor, a data fusion system, an unmanned ship autopilot, a U disk storage, a ground station QGC, a data transmission module interface and a shore-based controller. The RTK positioning system and the depth sounding sensor are connected to the data fusion system, the data fusion system is connected to the unmanned ship autopilot, the U disk storage is connected to the unmanned ship autopilot, the ground station QGC is wirelessly connected to the unmanned ship autopilot, the data transmission module interface is wirelessly connected to the unmanned ship autopilot, and the shore-based controller is connected to the data transmission module interface.

9. The system for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions according to claim 8, characterized in that: The process of implementing process control and event response mechanism within the system is as follows: (1) The RTK data reading subtask detects and parses the NMEA message after initializing the serial port, injects the updated latitude, longitude and time information into the circular buffer, and can be called by the data fusion module at any time; (2) The water depth data parsing subtask then decodes the SDDBT message in real time and writes the instantaneous water depth value into the ring buffer, waiting for fusion processing together with the positioning data; (3) The data fusion and transmission subtask periodically retrieves the ring buffer data. Once the associated water depth value and position data are found, the fusion and data packaging process is triggered, and the packaged data frame is sent to the unmanned ship and the LORA wireless link for external output.

10. The system for collecting and transmitting water depth data of an unmanned vessel with position association and redundant storage functions according to claim 8, characterized in that: The specific process of system parameter adjustment and status change is as follows: (1) When receiving the sampling start command, the system starts the data continuous recording and transmission process; (2) After receiving instructions such as stopping sampling or changing the transmission frequency, the system adjusts the corresponding subtask operating status and data writing strategy according to the instruction content.

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