Data transmission method and system of distributed wireless acoustic Doppler current profiler

Abstract

The invention relates to the technical field of data transmission, and discloses a data transmission method and system of a distributed wireless acoustic Doppler flow velocity profiler, which are realized based on a distributed control module and a distributed storage station in the flow velocity profiler. The distributed control module establishes two data links with the transfer gateway through the dual-communication module, hydrological data are collected and stored periodically, timestamps are generated, and after the hydrological data are transmitted to the gateway through the links, the gateway stores the data and feeds back a response instruction. And by summarizing multi-node timestamps, calculating the communication duration and the corresponding ratio, and when it is judged that the link state is poor, switching the functions of the two links. According to the method, through double-link redundancy design and dynamic switching, the problem of signal interference in a severe hydrological environment is effectively avoided, data loss and delay risks are reduced, the stability and timeliness of data transmission are guaranteed, and the actual requirements of scenes such as hydrological monitoring, flood control and disaster reduction are met.

Description

Technical Field

[0001] This application relates to the technical field of data transmission, and in particular to a data transmission method and system for a distributed wireless acoustic Doppler current profiler. Background Technology

[0002] The distributed wireless acoustic Doppler current profiler is a hydrological monitoring device based on the acoustic Doppler effect. It can be deployed in a distributed manner in water bodies such as rivers and oceans. By transmitting and receiving sound wave signals, it measures the current velocity profile data at different depths of the water body in real time. It has the ability to simultaneously monitor multiple measurement points and transmit wirelessly. It is widely used in fields such as hydrological and water resources surveys, flood control and disaster reduction, and water conservancy project monitoring. It is one of the core devices for realizing the automated and intelligent acquisition of hydrological data.

[0003] The mainstream data transmission methods for existing distributed wireless acoustic Doppler current profilers primarily rely on short-range wireless communication technologies, such as Bluetooth, ZigBee, and LoRa. The transmission process is as follows: after the current profilers at each distributed measurement point collect data, the data is first aggregated to a local gateway via short-range wireless communication. Then, the gateway transmits the integrated data to a remote monitoring center via a long-range communication module, thus completing the unified collection and transmission of data from multiple nodes.

[0004] In practical applications, such equipment is often deployed in harsh working environments such as rivers, lakes, and coastlines, where existing transmission methods are highly susceptible to environmental interference. Complex terrain can obstruct wireless signals, and the reflection and scattering effects of water can attenuate sound waves and wireless signal strength. At the same time, factors such as industrial electromagnetic interference and weather changes can also impact communication links, leading to signal interruptions and increased bit error rates during data transmission. This can result in data loss, duplicate transmissions, transmission delays, and other faults, severely affecting the timeliness of hydrological monitoring data and failing to meet the actual needs of hydrological monitoring. Summary of the Invention

[0005] To improve the timeliness of hydrological monitoring data, this application provides a data transmission method and system for a distributed wireless acoustic Doppler current profiler.

[0006] Firstly, this application provides a data transmission method for a distributed wireless acoustic Doppler current profiler, employing the following technical solution: A data transmission method for a distributed wireless acoustic Doppler current profiler, based on the acoustic Doppler current profiler having a distributed control module and a distributed storage station, includes the following steps: The distributed control module establishes a first data link with the relay gateway based on the first communication module, and simultaneously establishes a second data link with the relay gateway based on the second communication module. The distributed control module collects hydrological data according to the preset first cycle, saves the hydrological data to the distributed storage station, and generates the first timestamp; it sends the hydrological data and the preset request command to the relay gateway through the first data link, the relay gateway saves the hydrological data to the temporary storage station, generates the second timestamp, responds to the request command by calling the response command, and sends the response command to the distributed control module through the second data link; The distributed control module responds to the response command by generating response data, generating a third timestamp, and returning the response data to the relay gateway through the first data link; the relay gateway receives the response data, verifies that the response command and response data are valid, and then generates a fourth timestamp. The first, second, third, and fourth timestamps are sent and aggregated to the distributed control module or relay gateway; the data communication duration is calculated based on the first and second timestamps, the response communication duration is calculated based on the second and third timestamps, and the verification communication duration is calculated based on the third and fourth timestamps; the ratio of the data communication duration to the response communication duration is calculated as the first communication ratio, and the ratio of the verification communication duration to the response communication duration is calculated as the second communication ratio; If the second communication ratio is greater than the preset second reference ratio, and the first communication ratio is greater than the preset first reference ratio, then the first data link and the second data link are swapped.

[0007] By adopting the above technical solution and constructing dual data links to form transmission redundancy, the inherent limitations of a single short-range wireless communication link in harsh hydrological environments, such as susceptibility to terrain obstruction, water signal attenuation, and electromagnetic interference, are fundamentally compensated for, providing dual protection for data transmission. Simultaneously, by using timestamps to record key nodes throughout the entire process of data acquisition, transmission, response, and verification, and by calculating data communication duration, response communication duration, verification communication duration, and their corresponding ratios, the transmission efficiency and stability of the two links can be accurately quantified, avoiding the additional losses caused by blindly switching links. When both the second and first communication ratios exceed preset reference values, indicating poor current link transmission status, the functional roles of the two data links can be dynamically swapped. This allows core processes such as hydrological data transmission, response interaction, and verification feedback to be switched to a more stable and efficient link, effectively reducing the probability of data loss, duplicate transmissions, and transmission delays, ensuring that hydrological monitoring data can be transmitted to the remote monitoring center in a timely and complete manner.

[0008] Optionally, the step of the relay gateway saving hydrological data to a temporary storage station also includes the following sub-steps: The length of hydrological data is acquired in real time, and the difference between the current data length and the previous data length is calculated as the length difference. If the absolute value of the length difference is greater than the preset reference absolute value, the ratio of the current data length to the previous data length is calculated as the length ratio, and the second reference ratio is adjusted according to the positive correlation of the length ratio. If the amount of temporary data stored in the temporary storage station is greater than the preset reference amount, the temporary data will be sent to the remote backend, and the temporary data will be temporarily stored for the preset first number of cycles before being cleared. If the length difference is greater than the preset maximum reference difference, the reference quantity is reduced to the preset minimum quantity and the first quantity is increased to the preset maximum quantity; otherwise, if the length difference is less than the preset minimum reference difference, the reference quantity is increased to the preset maximum quantity and the first quantity is reduced to the preset minimum quantity; if the length difference is between the minimum and maximum reference difference, the reference data quantity and the first quantity are adjusted according to the negative correlation of the length ratio.

[0009] By adopting the above technical solution, and by dynamically adjusting the second reference ratio, reference quantity, and first quantity in conjunction with changes in the length of hydrological data, the data storage and transmission strategy can adaptively match data volume fluctuations. This avoids storage overflow or transmission congestion caused by sudden changes in data volume, and ensures that data is not lost through hierarchical temporary storage and clearing rules. At the same time, it makes the link switching judgment parameters more in line with the actual data transmission scenario.

[0010] Optionally, the step of the relay gateway saving hydrological data to a temporary storage station also includes the following sub-steps: If the length difference is greater than the preset maximum reference difference, wait for the remote backend to send a relay processing instruction, data recovery instruction, or real-time preservation instruction; If the relay gateway receives the relay processing instruction, it responds to the relay processing instruction by processing the unsent temporary data according to the first compression algorithm to obtain the first compressed data, and then sends the first compressed data to the remote backend. If the relay gateway receives a data recovery instruction, it responds to the data recovery instruction by processing the temporarily stored data using the second compression algorithm to obtain the second compressed data, and then sends the second compressed data to the remote backend. If the relay gateway receives a real-time preservation instruction, it responds by processing the unsent temporary data using a first compression algorithm to obtain first compressed data, processing the first compressed data and the temporarily stored temporary data using a second compression algorithm to obtain third compressed data, and sending the third compressed data to the remote backend.

[0011] By adopting the above technical solution, for scenarios with sudden changes in hydrological data volume, three types of instructions are used: waiting for remote backend relay processing, data recovery, or real-time preservation. Combined with differentiated compression algorithms, targeted processing is carried out on unsent temporary data and temporarily stored temporary data. This not only achieves offline data preservation and flexible adaptation to different processing needs, effectively avoiding the risk of data loss caused by sudden changes in data volume, but also improves data transmission efficiency through compression processing.

[0012] Optionally, the step of the distributed control module establishing a first data link with the relay gateway based on the first communication module and simultaneously establishing a second data link with the relay gateway based on the second communication module further includes the following steps: The output voltage of the lithium battery module is collected in real time to obtain the first voltage data, and the output voltage of the photovoltaic module is collected in real time to obtain the second voltage data; the difference between the first voltage data and the second voltage data is calculated as the voltage difference; the fluctuation amplitude of the first voltage data is calculated to obtain the first fluctuation data, and the fluctuation amplitude of the second voltage data is calculated to obtain the second fluctuation data. If the first fluctuation data is greater than the second fluctuation data and the voltage difference is within the preset voltage range, then switch the photovoltaic module to supply power; otherwise, switch the lithium battery module to supply power.

[0013] By adopting the above technical solution, the output voltage data, voltage difference and fluctuation range of lithium battery and photovoltaic module are monitored in real time, and the appropriate power supply module is dynamically switched. This not only gives full play to the advantages of the two power supply methods, but also allows for the precise selection of a more stable power source based on the voltage status, making it suitable for scenarios where remote monitoring points have no stable external power supply.

[0014] Optionally, if the first fluctuation data is greater than the second fluctuation data and the voltage difference is within a preset voltage range, then the photovoltaic module is switched to supply power; otherwise, the step of switching the lithium battery module to supply power further includes the following steps: If the photovoltaic module is switched to supply power, the duration shall be at least a preset first duration; if the lithium battery module is switched to supply power, the duration shall be at least a preset second duration; wherein the second duration is longer than the first duration. The second duration is adjusted based on the positive correlation of the first voltage data, and the ratio of the first fluctuation data to the second fluctuation data is calculated as the fluctuation ratio. The first duration is then adjusted based on the negative correlation of the fluctuation ratio. If neither the first communication module nor the second communication module is working and the second voltage data is greater than the first voltage data, then the photovoltaic module is controlled to supply power to the lithium battery module.

[0015] By adopting the above technical solution, the power supply switching time is dynamically adjusted based on voltage data, fluctuation amplitude, and communication status, achieving intelligent and refined power supply strategy. On the one hand, by positively adjusting the lithium battery power supply time and negatively adjusting the photovoltaic power supply time, energy distribution can be flexibly optimized according to voltage stability and fluctuation, avoiding energy loss caused by frequent switching of power supply modules and effectively extending the equipment's battery life. On the other hand, when the communication module is not working and the photovoltaic voltage is dominant, the photovoltaic system automatically controls the lithium battery to charge, ensuring that the battery power is continuously sufficient and preventing the core functions such as dual data link communication and data acquisition and storage from being affected by power outages.

[0016] Optionally, the step of the distributed control module establishing a first data link with the relay gateway based on the first communication module and simultaneously establishing a second data link with the relay gateway based on the second communication module further includes the following steps: The first signal strength is obtained based on the first communication module, and the second signal strength is obtained based on the second communication module; The average signal value and the signal difference are calculated based on the first signal strength and the second signal strength. If the average signal value is less than the preset signal reference value, and the absolute value of the signal difference is greater than the preset reference difference value, then the communication module corresponding to the highest value between the first signal strength and the second signal strength is selected as the enhanced communication module. The enhanced communication module is used to send hydrological data and amplify the radio frequency power of the enhanced communication module.

[0017] By adopting the above technical solution, the signal strength of the two communication modules is monitored in real time, and the average value and difference are calculated. When the network coverage is poor, the module with the stronger signal is automatically selected and its radio frequency power is amplified, which effectively improves the stability and reliability of data transmission.

[0018] Optionally, the step of amplifying and enhancing the radio frequency power of the communication module further includes the following steps: The ratio of the absolute value of the signal difference to the reference difference is used as the signal difference ratio. The amplification value of the RF power is adjusted according to the negative correlation between the signal difference ratio and the amplification value. If the signal difference ratio is greater than the preset first ratio, then the direction data facing the relay gateway is obtained, and a signal constraint command is generated based on the direction data. The signal constraint command is used to start the signal cluster board to constrain the transmission signal of the enhanced communication module to the direction facing the relay gateway.

[0019] By adopting the above technical solution, and through dynamically adjusting the RF power amplification value and combining it with directional data to activate the signal clustering board for directional signal transmission, the signal dispersion problem in areas with poor network coverage is effectively solved. On the one hand, the amplification power is intelligently adjusted according to the signal difference ratio, actively enhancing transmission capability when the signal is weak, ensuring effective data transmission in complex environments. On the other hand, the signal clustering board constrains the transmitted signal towards the relay gateway, significantly improving signal energy concentration, reducing energy waste and interference, and significantly improving the stability and efficiency of data transmission.

[0020] Optionally, the step of calculating the ratio of the absolute value of the signal difference to the reference difference as the signal difference ratio further includes the following steps: Identify modules that are not receiving power as idle power modules and disconnect the power supply lines of the idle power modules from the idle power modules. The power supply line is electrically connected to the preset detection module. When the first communication module and the second communication module are not transmitting data, the electromagnetic signal on the power supply line is collected as an electromagnetic interference signal. If the electromagnetic interference signal is greater than the preset first interference signal, the ratio of the electromagnetic interference signal to the first interference signal is calculated as the electromagnetic ratio, and the signal difference ratio is adjusted according to the negative correlation of the electromagnetic ratio.

[0021] By adopting the above technical solution, low-cost, real-time acquisition of electromagnetic interference signals is achieved by utilizing the power supply lines of idle power modules, thus solving the problem of signal evaluation being easily affected by interference in complex environments. By calculating the ratio of the electromagnetic interference signal to the first interference signal (electromagnetic ratio), and adjusting the signal difference ratio based on the negative correlation of the electromagnetic ratio, the signal difference ratio can dynamically reflect the intensity of environmental interference, ensuring the accuracy of signal evaluation under strong interference.

[0022] Optionally, the step of calculating the ratio of the absolute value of the signal difference to the reference difference as the signal difference ratio further includes the following steps: If the electromagnetic interference signal is less than the preset second interference signal, the electromagnetic interference signal is saved to the electromagnetic sequence; wherein the second interference signal is greater than the first interference signal, and the difference between the second interference signal and the first interference signal is within the preset interference range; If the electromagnetic interference signals in the electromagnetic sequence are continuously acquired and the number of electromagnetic interference signals in the electromagnetic sequence is greater than the preset acquisition number, then the average value of the electromagnetic interference signals in the electromagnetic sequence is calculated, and the first interference signal is updated based on the average value. If the electromagnetic interference signal in the electromagnetic sequence is acquired discontinuously and the number of discontinuities in the electromagnetic interference signal in the electromagnetic sequence is greater than the preset number of discontinuities, then the electromagnetic sequence is cleared.

[0023] By adopting the above technical solution, and through the serialized management and dynamic updating of electromagnetic interference signals, the accuracy and adaptability of interference assessment are achieved. On the one hand, by distinguishing interference signals of different intensities and saving them to an electromagnetic sequence, combined with continuous acquisition statistics and breakpoint judgment, the first interference signal can reflect the true level of environmental interference in real time, avoiding misjudgments caused by fixed thresholds. On the other hand, based on the updated interference signal, the calculation of the signal difference ratio is optimized, further improving the rationality of communication module selection and RF power adjustment, and effectively reducing the transmission error rate and packet loss rate caused by electromagnetic interference.

[0024] Secondly, this application provides a data transmission system for a distributed wireless acoustic Doppler current profiler, employing the following technical solution: A data transmission system for a distributed wireless acoustic Doppler current profiler includes a processor, wherein the processor performs the steps of the data transmission method for a distributed wireless acoustic Doppler current profiler as described in any of the preceding claims.

[0025] In summary, this application achieves at least one of the following beneficial technical effects: By constructing dual data links and dynamically evaluating communication status using timestamps, intelligent redundancy and switching of the links are realized, effectively addressing signal interference issues in harsh environments and significantly improving the stability and timeliness of hydrological data transmission. Simultaneously, through distributed storage, dynamic compression processing, and offline preservation command response for temporary data, data integrity and security are ensured, preventing data loss due to sudden changes in data volume or network failures. Furthermore, this application solves the problem of unstable power supply at remote monitoring points through an intelligent power supply strategy using lithium batteries and photovoltaic modules, extending the equipment's battery life. The overall solution fully considers the complexity and diversity of hydrological monitoring scenarios, comprehensively optimizing communication, data processing, and power supply to achieve high reliability, high adaptability, and intelligent operation of the system. Attached Figure Description

[0026] Figure 1 This is a step diagram of a data transmission method for a distributed wireless acoustic Doppler current profiler.

[0027] Figure 2 This is a diagram showing the sub-steps by which the relay gateway saves hydrological data to a temporary storage station. Detailed Implementation

[0028] The embodiments of this application are described in detail below, and examples of the embodiments are shown in the accompanying drawings.

[0029] In the description of this specification, the references to "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples" refer to specific features, structures, materials, or characteristics described in connection with the described embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0030] This application discloses a data transmission method for a distributed wireless acoustic Doppler current profiler. Based on the distributed control module and distributed storage station built into the acoustic Doppler current profiler, this embodiment of the distributed wireless acoustic Doppler current profiler (hereinafter referred to as the current profiler) is mainly used in harsh hydrological monitoring scenarios such as rivers, lakes, and coastal areas. It solves the problems of data transmission interruption, high error rate, and severe delay caused by existing short-range wireless communication links being easily affected by factors such as terrain obstruction, water signal attenuation, industrial electromagnetic interference, and meteorological changes. It achieves stable, efficient, and real-time transmission of hydrological monitoring data.

[0031] Reference Figure 1 The specific method in this embodiment is as follows: S1: Dual data link establishment process: After powering on, the distributed control module first completes initialization configuration, including GPIO port configuration, communication module parameter configuration, and timestamp unit calibration. Then, it simultaneously sends start commands to both the first and second communication modules. Upon responding to the commands, the two communication modules automatically scan for available Wi-Fi networks in the vicinity, identify and connect to a preset relay gateway Wi-Fi hotspot, such as SSID: Hydrology_Gateway, password: Identity authentication and link establishment are completed through a three-way handshake protocol.

[0032] The first data link established between the first communication module and the relay gateway is defaulted to a hydrological data and request command transmission link, with the data transmission port set to 8080. The second data link established between the second communication module and the relay gateway is defaulted to a response command transmission link, with the data transmission port set to 8081. Both links use the TCP / IP protocol for data transmission. After the link is established, the communication module feeds back the link connectivity status to the distributed control module every 100ms. The connectivity status code is 0x01 for normal and 0x00 for abnormal, ensuring that the link status is controllable in real time.

[0033] S2: Hydrological data acquisition, storage, and preliminary transmission: The distributed control module initiates hydrological data acquisition according to a preset first cycle. In this embodiment, the first cycle is set to 10 seconds by default. Those skilled in the art can adjust it within the range of 1 to 60 seconds via the host computer software according to actual monitoring needs. The acquired hydrological data includes flow velocity (measurement range: 0.01 m / s to 10 m / s, accuracy: ±1%), flow direction (measurement range: 0° to 360°, accuracy: ±2°), and water depth data (measurement range: 0.1 m to 100 m, accuracy: ±0.5%) at different water depths (sampling depth interval: 0.5 m, maximum sampling depth: 50 m). The data is encapsulated in JSON format, and the amount of data transmitted each time is fixed at 256 bytes, including a data header, valid data, and check bits, to ensure the standardization and consistency of data transmission.

[0034] After data acquisition is completed, the distributed control module first writes the hydrological data into the designated storage partition of the distributed storage station, with partition addresses ranging from 0x00000000 to 0x07FFFFFF. At the same time, it triggers the timestamp generation unit to record the current time as the first timestamp. The first timestamp and the hydrological data are bound and stored through a data index, with the index format being: device ID + acquisition time, which facilitates subsequent data traceability.

[0035] The distributed control module sends the encapsulated hydrological data and the preset request command to the relay gateway via the first data link, port 8080. The request command format is: 0x5A0x010x000x010x000xFA, where 0x5A is the frame header, 0x01 is the command type, 0x000x01 is the data length, and 0xFA is the checksum.

[0036] After receiving data through the corresponding port, the relay gateway first verifies the data using CRC32. If the verification passes, the hydrological data is immediately written to the SSD of the temporary storage station at the storage path: / tmp / hydrology_data / . Simultaneously, its own timestamp generation unit is triggered to record the current time as a second timestamp, which is bound to the hydrological data using the same data index. If the verification fails, the relay gateway sends a retransmission command to the distributed control module through the second data link. The command format is: 0x5A0x020x000x010x000xFB. After receiving the retransmission command, the distributed control module retransmits the batch of hydrological data and the request command. The maximum number of retransmissions is 3. If the number of retransmissions is exceeded, a transmission error log is recorded.

[0037] After the relay gateway completes data storage and generates the second timestamp, it parses the instruction type field of the request instruction, calls the preset response instruction, with the instruction format: 0x5A0x030x000x010x000xFC, and sends the response instruction to the distributed control module through the second data link, i.e. port 8081, to inform that the data has been successfully received and stored.

[0038] S3: Response Interaction and Verification Process: After receiving the response command via the second data link, the distributed control module first performs frame header identification and checksum verification. Upon successful verification, it immediately generates response data. The response data includes the current device ID (4 bytes), a first timestamp (20 bytes), and a command confirmation code (1 byte, 0x01 indicating confirmed reception), for a total data length of 64 bytes. It also records the current time as a third timestamp. The distributed control module then returns the response data to the relay gateway via the first data link (port 8080).

[0039] After receiving the response data, the relay gateway initiates a two-way verification process: First, it verifies whether the device ID in the response data matches the device ID in the previously received hydrological data; second, it verifies whether the first timestamp in the response data matches the acquisition time corresponding to the second timestamp stored in its own database, with a time deviation allowable range of ±500ms; third, it verifies whether the instruction confirmation code is a preset valid value. If all three verifications pass, the relay gateway records the current time as the fourth timestamp and marks the verification result as passed. If any verification fails, the relay gateway sends a verification failure instruction via the second data link, with the instruction format: 0x5A0x040x000x010x000xFD. The distributed control module receives this instruction, regenerates and resends the response data, and the number of resends does not exceed three.

[0040] S4: Communication Status Assessment Process After the distributed control module and the relay gateway complete the aforementioned data transmission and response through the link interaction, the first, second, third, and fourth timestamps are aggregated and sent to the relay gateway. The aggregation method is as follows: the relay gateway sends a timestamp request command through the second data link, and the distributed control module responds and uploads its own recorded timestamps. The central processing unit of the relay gateway calculates the key communication parameters according to the following formula: Data communication duration T1 = second timestamp - first timestamp, unit: ms, represents the total time taken for hydrological data to be sent from the distributed control module to the relay gateway for reception; The response communication duration T2 = third timestamp - second timestamp, in ms, represents the total time taken for the relay gateway to send the response command to the distributed control module to receive and generate response data; The verification communication duration T3 = fourth timestamp - third timestamp, in ms, represents the total time taken for the response data to be sent from the distributed control module to the relay gateway for successful verification. The first communication ratio R1 = T1 / T2 is used to quantify the relative efficiency of the data transmission link; The second communication ratio, R2 = T3 / T2, is used to quantify the relative efficiency of the data verification link.

[0041] In this embodiment, the first reference ratio R1_ref=1.5 and the second reference ratio R2_ref=1.2 are preset. The above reference ratios can be flexibly adjusted in the range of 0.8 to 2.0 according to the communication environment of the actual application scenario, such as interference intensity and transmission distance, through the remote background configuration tool to ensure the adaptability of the link status assessment.

[0042] S5: Dynamic switching process between dual data links: After the relay gateway completes the above parameter calculations, it compares and judges R1 with R1_ref and R2 with R2_ref: If R2 > R2_ref and R1 > R1_ref, it is determined that the current transmission status of the first data link (data transmission link) and the second data link (response command link) is not good, such as excessive delay or low transmission efficiency. Immediately generate a link swap command with the following format: 0x5A0x050x000x010x000xFE, and send it to the distributed control module through the second data link. If R2≤R2_ref or R1≤R1_ref, the current transmission status of the two links is determined to be normal, and the original link function allocation remains unchanged.

[0043] Upon receiving the link swap instruction, the distributed control module immediately executes a link function switch operation: switching the function of the original first data link (port 8080) to an acknowledgment instruction transmission link, and the function of the original second data link (port 8081) to a hydrological data and request instruction transmission link. The switchover process is implemented through port mapping table updates, taking ≤10ms, and does not interrupt ongoing data transmission. If there are any incomplete data packets, the switchover is performed only after their transmission is complete. After the switchover is complete, the distributed control module sends a link switchover confirmation instruction to the relay gateway. The instruction format is: 0x5A0x060x000x010x000xFF. Upon receiving this instruction, the relay gateway updates its local link function configuration, completing one dynamic link adjustment.

[0044] Reference Figure 2 In this embodiment, the step of the relay gateway saving hydrological data to the temporary storage station further includes the following sub-steps: S2.1 Data Length Monitoring and Dynamic Adjustment of the Second Reference Ratio: During the process of writing hydrological data to the temporary storage station, the relay gateway synchronously and in real time parses the byte length of the hydrological data. The data length of the current hydrological data is denoted as L_current, and the data length of the hydrological data collected in the previous cycle is denoted as L_prev. The length difference ΔL = L_current - L_prev is calculated.

[0045] The default reference absolute value is 32 bytes. When |ΔL|>32 bytes, the length ratio K=L_current / L_prev is calculated. The second reference ratio is adjusted according to the positive correlation. The adjustment formula is R2_new=R2_ref×K, where R2_new is the adjusted second reference ratio and R2_ref is the initial default second reference ratio (1.2). The value range of R2_new is limited to 0.8 to 2.0. If the calculation result exceeds this range, the nearest value within the range is taken as the final adjustment value.

[0046] S2.2 Temporary Data Quantity Monitoring and Batch Transmission Control: The relay gateway continuously monitors the total amount of temporary data N stored in the temporary storage station. The preset reference number is 100 records. When N > 100 records, the relay gateway initiates a batch transmission mechanism to send all temporary data in the temporary storage station to the remote backend via the Ethernet interface.

[0047] After the data is sent, a temporary storage timer is started, with a preset initial quantity of 5 cycles. After 5 collection cycles of temporary storage, the temporary data will be cleared by the relay gateway to ensure that the temporary storage station has sufficient storage space to receive subsequent data.

[0048] S2.3 Length Difference Grading Judgment and Dynamic Adjustment of Storage Parameters: The preset maximum reference difference is 64 bytes, the minimum reference difference is -64 bytes, the minimum number of references is 50, the maximum number of references is 200, the maximum first number is 10 cycles, and the minimum first number is 2 cycles.

[0049] When ΔL > 64 bytes, the number of references is adjusted to 50, and the first number is adjusted to 10 cycles. When ΔL < -64 bytes, the number of references is adjusted to 200, and the first number is adjusted to 2 cycles. When -64 bytes ≤ ΔL ≤ 64 bytes, the reference number and the first number are adjusted negatively according to the length ratio K. The formula for adjusting the reference number is N_adjust=200-(K-0.5)×150, and the formula for adjusting the first number is T_adjust=2+(2-K)×8, where N_adjust is the adjusted reference number and T_adjust is the adjusted first number. N_adjust needs to be maintained between 50 and 200, and T_adjust needs to be maintained between 2 and 10 cycles.

[0050] The above scheme further optimizes the adaptability of data storage and transmission: by leveraging real-time monitoring and hierarchical judgment of data length changes, dynamic adjustment of the second reference ratio, reference quantity, and first quantity is achieved, enabling the link switching judgment parameters to adapt in real time to data volume fluctuations, avoiding the inapplicability of fixed parameters in scenarios with sudden changes in data volume; through hierarchical temporary storage and batch transmission rules, storage overflow caused by a surge in data volume at temporary storage stations is prevented, and network congestion caused by frequent transmission when the data volume is too small is avoided, while ensuring the complete retention of all collected data, further improving the stability of hydrological monitoring data transmission in harsh environments.

[0051] In this embodiment, the step of the relay gateway saving hydrological data to the temporary storage station further includes the following sub-steps: S2.4 Command Response and Differentiated Compression Processing When Data Volume Changes Abruptly: When the transit gateway determines through S2.3 that the length difference is greater than the maximum reference difference, it immediately stops the batch transmission triggering mechanism of temporary data, enters the instruction waiting state, and starts the waiting timer.

[0052] The default waiting timeout is 30 seconds. If no instruction is received from the remote backend within 30 seconds, the execution logic of the real-time security instruction will be automatically triggered.

[0053] The relay gateway listens to the remote backend's command transmission port in real time, receives and parses command frames. Command frames uniformly adopt the format of "frame header + command type + data length + checksum," where the frame header is fixed at 0x5A. a. If the parsed instruction type is 0x07, it is determined to be a relay processing instruction. The relay gateway filters the temporary data in the temporary storage station that has not been sent to the remote backend as the data to be processed. b. If the parsed instruction type is 0x08, it is determined to be a data recovery instruction. The transit gateway filters the historical temporary data that has been temporarily stored and not cleared in the temporary storage station as the data to be processed. c. If the parsed instruction type is 0x09, it is determined to be a real-time preservation instruction. The transit gateway filters the unsent temporary data and the historical temporary data that has been temporarily stored in the temporary storage station as the data to be processed.

[0054] For relay processing instructions, the first compression algorithm is used to compress the unsent temporary data. The first compression algorithm is LZ77, and the compression ratio is controlled between 3:1 and 5:1. After compression, the first compressed data is generated. The first compressed data is divided into blocks of 1MB each and encapsulated. After encapsulation, it is sent to the remote backend block by block through the Ethernet interface. After each block is sent, the remote backend is waited for a receipt confirmation instruction. After confirmation, the next block is sent.

[0055] In response to the data recovery command, a second compression algorithm is used to compress the temporarily stored historical data. The second compression algorithm uses Huffman coding, and the compression ratio is controlled between 2.5:1 and 4:1. After compression, second compressed data is generated. The second compressed data is encapsulated in 1MB blocks and sent to the remote backend block by block. During the transmission process, the transmission status of each block of data is recorded to ensure data integrity.

[0056] For real-time preservation commands, the LZ77 algorithm is first used to compress the unsent temporary data to generate the first compressed data. Then, the first compressed data is merged with the temporarily stored historical temporary data to form merged data. Huffman coding is used to perform secondary compression on the merged data to generate the third compressed data. The third compressed data is encapsulated in 1MB blocks. When dividing the data into blocks, a block index and a checksum are added to each block. The data is sent to the remote backend block by block. After receiving the data, the remote backend reassembles the data using the block index and verifies the data integrity using the checksum.

[0057] Through the above sub-steps, this application has formed a precise response mechanism for scenarios of sudden changes in hydrological data volume: by using a 30-second timeout and adapting to three types of instructions, it achieves flexible matching for different data processing needs and avoids blind transmission when the data volume surges; the differentiated selection of LZ77 algorithm and Huffman coding ensures both fast compressed transmission of unsent data and efficient storage and recovery of historical data, and the clear limitation of compression ratio ensures the predictability of transmission efficiency; the block encapsulation and confirmation mechanism further reduces the risk of transmission loss of large-volume compressed data.

[0058] In this embodiment, the step of the distributed control module establishing a first data link with the relay gateway based on the first communication module and simultaneously establishing a second data link with the relay gateway based on the second communication module further includes the following steps: Intelligent power supply switching during S1.1 dual-link establishment process: While the distributed control module starts the first communication module to establish a data link with the second communication module, it also starts the power monitoring unit. The unit collects the output voltage of the lithium battery module in real time through the built-in ADC acquisition channel as the first voltage data, and collects the output voltage of the photovoltaic module in real time through another independent ADC acquisition channel as the second voltage data. The acquisition frequency is set to 10Hz to ensure the real-time performance of the voltage data.

[0059] The distributed control module calculates the voltage difference for each set of first and second voltage data collected. The voltage difference is the absolute value of the difference between the first and second voltage data, i.e., ΔV=|V1-V2|, where V1 is the first voltage data and V2 is the second voltage data.

[0060] The fluctuation amplitude calculation time window is set to 1 minute. Within each time window, the distributed control module calculates the maximum value V1_max and the minimum value V1_min of the first voltage data and calculates the first fluctuation data ΔV1=V1_max-V1_min; at the same time, it calculates the maximum value V2_max and the minimum value V2_min of the second voltage data and calculates the second fluctuation data ΔV2=V2_max-V2_min.

[0061] The preset voltage range is 0.5V to 1.5V. The distributed control module substitutes the first fluctuation data, the second fluctuation data, and the voltage difference into the judgment logic: if the first fluctuation data is greater than the second fluctuation data, and the voltage difference is between 0.5V and 1.5V, then the photovoltaic module power supply switching command is triggered; if none of the above conditions are met, then the lithium battery module power supply switching command is triggered.

[0062] The distributed control module sends corresponding power switching commands to the power management chip via the I2C bus. After receiving the commands, the power management chip controls the internal MOSFET switches to switch the power supply circuit: when the photovoltaic module is triggered to supply power, the power supply connection between the lithium battery module and the core circuit is disconnected, and the power supply connection between the photovoltaic module and the core circuit is closed; when the lithium battery module is triggered to supply power, the power supply connection between the photovoltaic module and the core circuit is disconnected, and the power supply connection between the lithium battery module and the core circuit is closed. The switching process takes ≤5ms, ensuring that the power supply switching does not affect the data link establishment process.

[0063] Through the above sub-steps, this application achieves dynamic adaptation of power supply strategy during the dual data link establishment stage: high-frequency voltage acquisition at 10Hz and fluctuation amplitude calculation within a 1-minute window can accurately capture the output stability differences between the two power supply modules. The voltage difference range setting of 0.5V to 1.5V avoids frequent switching caused by small voltage fluctuations and can accurately identify the output capability differences between the two power supply modules.

[0064] In this embodiment, if the first fluctuation data is greater than the second fluctuation data and the voltage difference is within a preset voltage range, then the photovoltaic module is switched to supply power; otherwise, the step of switching the lithium battery module to supply power further includes the following steps: S1.2 Power Supply Duration Adjustment and Photovoltaic Charging Control: Preset power supply duration: The first duration is 5 minutes, and the second duration is 10 minutes. The second duration is always longer than the first duration to ensure the stability of the lithium battery power supply.

[0065] When the distributed control module triggers the photovoltaic module power supply switching command, the power supply duration of the photovoltaic module shall not be less than the first duration reference value; if the lithium battery module power supply switching command is triggered, the power supply duration of the lithium battery module shall not be less than the second duration reference value, so as to avoid energy loss caused by frequent switching of power supply circuits in a short period of time.

[0066] Dynamic adjustment of lithium battery power supply duration: The second duration is adjusted based on a positive correlation with the first voltage data. The adjustment formula is T2_adjust=T2_base+(V1-12V)×2, where T2_adjust is the adjusted second duration, T2_base is the 10-minute baseline value for the second duration, and V1 is the first voltage data. The value of T2_adjust is limited to 5 minutes to 20 minutes. When the calculated result exceeds this range, the critical value within the range is taken as the final duration.

[0067] Dynamic adjustment of photovoltaic power supply duration: The fluctuation ratio K_v = ΔV1 / ΔV2 is calculated, where ΔV1 is the first fluctuation data and ΔV2 is the second fluctuation data. The first duration is adjusted based on the negative correlation of the fluctuation ratio, using the formula T1_adjust = T1_base - (K_v - 1) × 1, where T1_adjust is the adjusted first duration and T1_base is a 5-minute baseline value for the first duration. The value of T1_adjust is limited to 3 to 8 minutes to ensure the stability and adaptability of photovoltaic power supply.

[0068] Communication module idle state judgment: The distributed control module monitors the working status of the first communication module and the second communication module in real time. If neither module transmits data and the cumulative idle time reaches 30 seconds, it is judged to be in a communication idle state.

[0069] Photovoltaic charging trigger logic: When in communication idle state and the second voltage data is greater than the first voltage data, the distributed control module sends a charging control command to the power management chip. The power management chip closes the charging circuit between the photovoltaic module and the lithium battery module, and controls the photovoltaic module to charge the lithium battery module. The charging current is limited to 0.5A to avoid overcharging and damaging the lithium battery.

[0070] Charging stop condition: When the first voltage data of the lithium battery module rises to 13.8V, or when the communication module resumes working state, the distributed control module immediately sends a charging stop command, disconnects the charging circuit, and switches back to the original power supply mode.

[0071] Through the above sub-steps, this application achieves refined power supply strategy and optimized energy utilization: the reference setting and dynamic adjustment formula for the first and second durations not only avoids frequent power supply switching caused by small voltage fluctuations, but also adapts the duration according to the actual output state of the power supply module, reducing energy loss; the charging control logic of the photovoltaic module makes full use of the photovoltaic energy during communication idle periods to ensure that the lithium battery power is continuously sufficient.

[0072] In this embodiment, the step of amplifying and enhancing the radio frequency power of the communication module further includes the following steps: S1.3 Signal Enhancement and Directional Transmission Control: S1.3.1 Dynamic adjustment of radio frequency power and directional transmission control: After determining the enhanced communication module, the distributed control module extracts the absolute value of the calculated signal difference and the preset reference difference, and calculates the signal difference ratio K_s=|ΔS| / S_ref, where |ΔS| is the absolute value of the signal difference, S_ref is the preset reference difference, and S_ref is set to 10dBm.

[0073] The negative correlation adjustment of the RF power amplification value is performed based on the signal difference ratio. The RF power amplification base P_base is set to 6dBm, and the adjustment formula is P_adjust=P_base-(K_s-1)×3, where P_adjust is the adjusted RF power amplification value. The value range of P_adjust is limited to 6dBm to 20dBm. If the calculation result exceeds this range, the critical value within the range is taken as the final amplification value.

[0074] The distributed control module sends the adjusted amplification value to the RF control chip of the enhanced communication module via the SPI bus. After receiving the instruction, the RF control chip configures the internal power control register to complete the real-time adjustment of the RF power, ensuring that the signal transmission capability is adapted to the environment.

[0075] The first ratio K1 is preset to 2.5. The distributed control module compares the signal difference ratio K_s with K1. If K_s > K1, it is determined that the current signal difference is significant and the directional transmission mechanism needs to be activated.

[0076] The distributed control module triggers the GPS positioning module to work through the UART interface, and obtains the real-time position data of the current profiler and the preset position data of the relay gateway. Based on the two position data, the azimuth and elevation angles are calculated to form the direction data towards the relay gateway. The direction data is updated at a frequency of 1Hz.

[0077] The distributed control module generates signal constraint commands based on the direction data. The commands include azimuth angle parameters, pitch angle parameters, and start flags. The signal constraint commands are sent to the control unit of the signal cluster board via the I2C bus.

[0078] After receiving the command, the signal cluster board control unit drives the internal servo motor to adjust the angle of the antenna array, compressing the radiation angle of the transmission signal of the enhanced communication module from omnidirectional to 30 degrees, so that the signal energy is concentrated towards the relay gateway.

[0079] During directional transmission, the distributed control module compares the updated directional data with the current angle parameters of the signal cluster board in real time. If the deviation exceeds 5 degrees, an angle correction command is generated to drive the signal cluster board to make real-time adjustments to ensure directional accuracy.

[0080] Through the above sub-steps, this application achieves precise optimization of communication performance in weak signal environments: the quantitative calculation of the signal difference ratio and the negative correlation adjustment formula enable the RF power amplification value to dynamically match the degree of signal difference, avoiding energy waste caused by excessive power amplification or transmission failure caused by insufficient amplification; the 30-degree directional radiation angle design and real-time angle correction mechanism significantly improve the signal energy concentration and reduce the impact of environmental interference on transmission.

[0081] In this embodiment, the step of calculating the ratio of the absolute value of the signal difference to the reference difference as the signal difference ratio further includes the following steps: S1.3.2 Electromagnetic interference monitoring and dynamic correction of signal difference ratio: While calculating the signal difference ratio, the distributed control module receives real-time operating status signals of each power supply module from the power management chip, and identifies power supply modules that are not currently supplying power as idle power supply modules.

[0082] The distributed control module outputs control signals through the GPIO port to drive the relay to disconnect the power supply line of the idle power module from the main power supply circuit, ensuring that the power supply line is electrically isolated from the main circuit and avoiding interference from the main circuit signal to the electromagnetic acquisition.

[0083] After the relay completes its operation, the disconnected power supply line is connected to the signal input terminal of the preset electromagnetic interference detection module via a wired connection. The electromagnetic interference detection module starts up and enters the signal acquisition state, with the acquisition frequency band set to 200kHz to 2.4GHz and the acquisition accuracy set to 0.1μV / m.

[0084] The distributed control module monitors the transmission status of the first and second communication modules in real time. When neither module transmits data and the idle time reaches 100ms, the electromagnetic interference detection module is triggered to start collecting data. The collection frequency is set to 10Hz, and five sets of electromagnetic signals are collected continuously. The average value is taken as the final electromagnetic interference signal.

[0085] The first interference signal is preset to 5μV / m. The distributed control module compares the collected electromagnetic interference signal with the first interference signal. If the electromagnetic interference signal is greater than the first interference signal, the electromagnetic ratio K_e is calculated as electromagnetic interference signal / first interference signal.

[0086] The initially calculated signal difference ratio is negatively adjusted based on the electromagnetic ratio. The adjustment formula is K_s_adjust=K_s×(2-K_e), where K_s_adjust is the adjusted signal difference ratio and K_s is the initial signal difference ratio. The value of K_s_adjust is limited to 0.5 to 3.0. If the calculation result exceeds this range, the critical value within the range is taken as the final correction value.

[0087] The adjusted signal difference ratio replaces the initial signal difference ratio and is used for subsequent adjustment of the RF power amplification value and triggering of the directional transmission mechanism; if the electromagnetic interference signal is less than or equal to the first interference signal, the initial signal difference ratio is directly used for subsequent processes.

[0088] Through the above sub-steps, this application achieves accurate correction of signal evaluation under electromagnetic interference environment: using the power supply line of the idle power module as the electromagnetic acquisition carrier, there is no need to deploy a dedicated acquisition antenna, which reduces hardware cost and deployment complexity; the 100ms idle transmission trigger condition and the method of averaging multiple acquisitions ensure the accuracy of electromagnetic interference signal acquisition and avoid the interference of communication signals on the acquisition results; the clear electromagnetic ratio adjustment formula and value range enable the signal difference ratio to dynamically adapt to the environmental interference intensity, avoiding improper radio frequency power adjustment or false triggering of directional mechanism caused by signal evaluation distortion under strong interference.

[0089] In this embodiment, the step of calculating the ratio of the absolute value of the signal difference to the reference difference as the signal difference ratio further includes the following steps: S1.3.3 Electromagnetic interference signal serialization management and dynamic update of the first interference signal: The second interference signal is preset to 10μV / m, and the difference between the second interference signal and the first interference signal is set to 5μV / m. This difference is within the preset interference range of 3μV / m to 8μV / m, and the threshold for graded storage of interference signals is clearly defined.

[0090] After acquiring the electromagnetic interference signal, the distributed control module compares it with the second interference signal. If the electromagnetic interference signal is smaller than the second interference signal, the electromagnetic interference signal is stored in the preset electromagnetic sequence according to the acquisition time. The maximum storage capacity of the electromagnetic sequence is set to 100 records. If the sequence is full when new data is stored, the earliest stored data will be overwritten.

[0091] The distributed control module monitors the continuity of signal acquisition in the electromagnetic sequence in real time. The threshold for the time interval between two adjacent electromagnetic interference signal acquisitions is set to 1 second. If the interval between two acquisitions does not exceed 1 second, it is determined to be continuous acquisition; if it exceeds 1 second, it is determined to be an acquisition breakpoint and a breakpoint event is recorded.

[0092] The preset number of samples is 50. When the number of continuously sampled electromagnetic interference signals in the electromagnetic sequence is greater than 50, the distributed control module starts the average value calculation process, sums up all the continuously sampled electromagnetic interference signals in the sequence and divides by the number of signals to obtain the average value of the electromagnetic interference signal.

[0093] The first interference signal is updated based on the calculated average value. The update formula is V1_inter_new = average value of electromagnetic interference signal. The range of the updated first interference signal is limited to 3μV / m to 8μV / m. If the average value exceeds this range, the critical value within the range is taken as the new first interference signal. The updated first interference signal is immediately used for subsequent electromagnetic ratio calculation and signal difference ratio correction.

[0094] The preset number of non-continuous signals is 5. The distributed control module counts the number of acquisition breakpoints in the electromagnetic sequence in real time. If the number of breakpoints is greater than 5, it is determined that the signal acquisition effectiveness in the electromagnetic sequence is insufficient. The electromagnetic sequence is immediately cleared, all stored electromagnetic interference signals in the sequence are deleted, and the acquisition of interference signals and sequence construction are restarted.

[0095] After the electromagnetic sequence is updated or cleared, the distributed control module records an operation log, including the update time, the new first interference signal value, or the reason for clearing, providing a basis for subsequent troubleshooting and parameter optimization.

[0096] Through the aforementioned sub-steps, this application achieves adaptive iterative optimization of the interference assessment threshold: the explicit setting of the second interference signal and interference range provides a clear standard for the hierarchical storage of electromagnetic interference signals; the continuous acquisition judgment and breakpoint statistics mechanism ensures the validity and representativeness of the data in the electromagnetic sequence; the first interference signal update formula based on the sequence average value enables the assessment threshold to be dynamically adjusted in real time to follow the actual level of environmental interference, completely solving the problem of misjudgment when the fixed threshold changes with the interference environment. This scheme further improves the accuracy of electromagnetic interference assessment, making subsequent signal difference ratio correction, RF power adjustment, and directional transmission triggering more closely aligned with the actual environment.

[0097] This application also discloses a data transmission system for a distributed wireless acoustic Doppler current profiler, including a processor, wherein the processor executes the steps of the data transmission method for the distributed wireless acoustic Doppler current profiler as described in any of the preceding embodiments.

[0098] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A data transmission method for a distributed wireless acoustic Doppler current profiler, characterized in that, Based on an acoustic Doppler current profiler incorporating a distributed control module and a distributed storage station, the method includes the following steps: The distributed control module establishes a first data link with the relay gateway based on the first communication module, and simultaneously establishes a second data link with the relay gateway based on the second communication module. The distributed control module collects hydrological data according to the preset first cycle, saves the hydrological data to the distributed storage station, and generates the first timestamp. Hydrological data and preset request instructions are sent to the relay gateway through the first data link. The relay gateway saves the hydrological data to a temporary storage station, generates a second timestamp, calls the response instruction in response to the request instruction, and sends the response instruction to the distributed control module through the second data link. The distributed control module responds to the response command by generating response data, generating a third timestamp, and returning the response data to the relay gateway through the first data link. The relay gateway receives the response data and generates a fourth timestamp after verifying that the response command and response data have passed. Send the first, second, third, and fourth timestamps to the distributed control module or relay gateway for aggregation; The data communication duration is calculated based on the first and second timestamps, the response communication duration is calculated based on the second and third timestamps, and the verification communication duration is calculated based on the third and fourth timestamps. The ratio of data communication duration to response communication duration is used as the first communication ratio, and the ratio of verification communication duration to response communication duration is used as the second communication ratio. If the second communication ratio is greater than the preset second reference ratio, and the first communication ratio is greater than the preset first reference ratio, then the first data link and the second data link are swapped.

2. The data transmission method of the distributed wireless acoustic Doppler current profiler according to claim 1, characterized in that, The process of the relay gateway saving hydrological data to a temporary storage station also includes the following sub-steps: The length of hydrological data is acquired in real time, and the difference between the current data length and the previous data length is calculated as the length difference. If the absolute value of the length difference is greater than the preset reference absolute value, the ratio of the current data length to the previous data length is calculated as the length ratio, and the second reference ratio is adjusted according to the positive correlation of the length ratio. If the amount of temporary data stored in the temporary storage station is greater than the preset reference amount, the temporary data will be sent to the remote backend, and the temporary data will be temporarily stored for the preset first number of cycles before being cleared. If the length difference is greater than the preset maximum reference difference, the reference quantity will be reduced to the preset minimum quantity, and the first quantity will be increased to the preset maximum quantity. Otherwise, if the length difference is less than the preset minimum reference difference, the reference quantity will be increased to the preset maximum quantity, and the first quantity will be reduced to the preset minimum quantity. If the length difference is between the minimum and maximum reference difference, then the reference data volume and the first quantity are adjusted according to the negative correlation of the length ratio.

3. The data transmission method of the distributed wireless acoustic Doppler current profiler according to claim 2, characterized in that, The process of the relay gateway saving hydrological data to a temporary storage station also includes the following sub-steps: If the length difference is greater than the preset maximum reference difference, wait for the remote backend to send a relay processing instruction, data recovery instruction, or real-time preservation instruction; If the relay gateway receives the relay processing instruction, it responds to the relay processing instruction by processing the unsent temporary data according to the first compression algorithm to obtain the first compressed data, and then sends the first compressed data to the remote backend. If the relay gateway receives a data recovery instruction, it responds to the data recovery instruction by processing the temporarily stored data using the second compression algorithm to obtain the second compressed data, and then sends the second compressed data to the remote backend. If the relay gateway receives a real-time preservation instruction, it responds by processing the unsent temporary data using a first compression algorithm to obtain first compressed data, processing the first compressed data and the temporarily stored temporary data using a second compression algorithm to obtain third compressed data, and sending the third compressed data to the remote backend.

4. The data transmission method of the distributed wireless acoustic Doppler current profiler according to claim 1, characterized in that, The step of the distributed control module establishing a first data link with the relay gateway based on the first communication module and simultaneously establishing a second data link with the relay gateway based on the second communication module also includes the following steps: The output voltage of the lithium battery module is collected in real time to obtain the first voltage data, and the output voltage of the photovoltaic module is collected in real time to obtain the second voltage data; the difference between the first voltage data and the second voltage data is calculated as the voltage difference. The fluctuation amplitude of the first voltage data is calculated to obtain the first fluctuation data, and the fluctuation amplitude of the second voltage data is calculated to obtain the second fluctuation data; If the first fluctuation data is greater than the second fluctuation data and the voltage difference is within the preset voltage range, then switch the photovoltaic module to supply power. Otherwise, switch to the lithium battery module for power supply.

5. The data transmission method of the distributed wireless acoustic Doppler current profiler according to claim 4, characterized in that, If the first fluctuation data is greater than the second fluctuation data and the voltage difference is within the preset voltage range, then the photovoltaic module is switched to supply power; otherwise, the step of switching the lithium battery module to supply power also includes the following steps: If the photovoltaic module is switched to supply power, the duration shall be at least a preset first duration; if the lithium battery module is switched to supply power, the duration shall be at least a preset second duration; wherein the second duration is longer than the first duration. The second duration is adjusted based on the positive correlation of the first voltage data, and the ratio of the first fluctuation data to the second fluctuation data is calculated as the fluctuation ratio. The first duration is then adjusted based on the negative correlation of the fluctuation ratio. If neither the first communication module nor the second communication module is working and the second voltage data is greater than the first voltage data, then the photovoltaic module is controlled to supply power to the lithium battery module.

6. The data transmission method of the distributed wireless acoustic Doppler current profiler according to claim 1, characterized in that, The step of the distributed control module establishing a first data link with the relay gateway based on the first communication module and simultaneously establishing a second data link with the relay gateway based on the second communication module also includes the following steps: The first signal strength is obtained based on the first communication module, and the second signal strength is obtained based on the second communication module; The average signal value and the signal difference are calculated based on the first signal strength and the second signal strength. If the average signal value is less than the preset signal reference value, and the absolute value of the signal difference is greater than the preset reference difference value, then the communication module corresponding to the highest value between the first signal strength and the second signal strength is selected as the enhanced communication module. The enhanced communication module is used to send hydrological data and amplify the radio frequency power of the enhanced communication module.

7. The data transmission method of the distributed wireless acoustic Doppler current profiler according to claim 6, characterized in that, The steps of amplifying and enhancing the radio frequency power of the communication module also include the following steps: The ratio of the absolute value of the signal difference to the reference difference is used as the signal difference ratio. The amplification value of the RF power is adjusted according to the negative correlation between the signal difference ratio and the amplification value. If the signal difference ratio is greater than the preset first ratio, then the direction data facing the relay gateway is obtained, and a signal constraint command is generated based on the direction data. The signal constraint command is used to start the signal cluster board to constrain the transmission signal of the enhanced communication module to the direction facing the relay gateway.

8. The data transmission method of the distributed wireless acoustic Doppler current profiler according to claim 1, characterized in that, The step of calculating the ratio of the absolute value of the signal difference to the reference difference as the signal difference ratio also includes the following steps: Identify modules that are not receiving power as idle power modules and disconnect the power supply lines of the idle power modules from the idle power modules. The power supply line is electrically connected to the preset detection module. When the first communication module and the second communication module are not transmitting data, the electromagnetic signal on the power supply line is collected as an electromagnetic interference signal. If the electromagnetic interference signal is greater than the preset first interference signal, the ratio of the electromagnetic interference signal to the first interference signal is calculated as the electromagnetic ratio, and the signal difference ratio is adjusted according to the negative correlation of the electromagnetic ratio.

9. The data transmission method of the distributed wireless acoustic Doppler current profiler according to claim 8, characterized in that, The step of calculating the ratio of the absolute value of the signal difference to the reference difference as the signal difference ratio also includes the following steps: If the electromagnetic interference signal is less than the preset second interference signal, the electromagnetic interference signal is saved to the electromagnetic sequence; wherein the second interference signal is greater than the first interference signal, and the difference between the second interference signal and the first interference signal is within the preset interference range; If the electromagnetic interference signals in the electromagnetic sequence are continuously acquired and the number of electromagnetic interference signals in the electromagnetic sequence is greater than the preset acquisition number, then the average value of the electromagnetic interference signals in the electromagnetic sequence is calculated, and the first interference signal is updated based on the average value. If the electromagnetic interference signal in the electromagnetic sequence is acquired discontinuously and the number of discontinuities in the electromagnetic interference signal in the electromagnetic sequence is greater than the preset number of discontinuities, then the electromagnetic sequence is cleared.

10. A data transmission system for a distributed wireless acoustic Doppler current profiler, characterized in that, The device includes a processor that performs the steps of the data transmission method for a distributed wireless acoustic Doppler current profiler as described in any one of claims 1-9.

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