A dual-mode positioning method for acoustic beacons and surface radio signals of marine electronic anchors

Abstract

This invention relates to the field of marine electronic anchor technology, specifically to a dual-mode positioning method for marine electronic anchors using an acoustic beacon and surface radio. The method involves collecting real-time acoustic environmental parameters of the surrounding water body via an underwater acoustic beacon, and transmitting a target positioning acoustic signal generated based on these parameters to a surface monitoring terminal. After transmitting the underwater acoustic beacon's status information and the real-time acoustic environmental parameters to a surface radio module, the surface radio module transmits its status information, real-time acoustic environmental parameters, and location information to the surface monitoring terminal. At the surface monitoring terminal, the target positioning acoustic signal is corrected based on the real-time acoustic environmental parameters, and the geographical location of the underwater acoustic beacon is calculated based on the location information. The reliability of the corrected target positioning acoustic signal and geographical location is verified based on the status information, and positioning information is output based on the verification results. This method solves the problem of providing high-precision positioning with existing marine electronic anchors.

Description

Technical Field

[0001] This invention relates to the field of marine electronic anchor technology, specifically to a dual-mode positioning method for marine electronic anchors using both acoustic beacons and surface radio. Background Technology

[0002] Marine electronic anchors are key tools for the long-term deployment and retrieval of underwater equipment. Their role is to reliably mark and continuously track underwater platforms and equipment that are submerged or hovering. However, current positioning methods for marine electronic anchors mainly rely on acoustic positioning or surface radio positioning. This involves underwater acoustic beacons emitting signals for the mother ship to detect and perform relative positioning, while the surface buoy's radio module reports its own position. However, this method treats acoustic positioning and radio reporting as two independent processes. Underwater acoustic beacons emit fixed positioning signals in the complex and ever-changing ocean channels, and their propagation is significantly affected by changes in sound speed caused by seawater variations, resulting in sound ray bending and signal distortion. Furthermore, the calculation lacks awareness of information related to the underwater acoustic beacon's emitted signals and can only use historical or average sound speed data and potentially inaccurate surface positions for calculation, which cannot ensure the accuracy of positioning. Summary of the Invention

[0003] To address the technical problem that existing positioning methods based on marine electronic anchors cannot guarantee positioning accuracy, this application provides a dual-mode positioning method using both acoustic beacons and maritime radio signals from marine electronic anchors.

[0004] The acoustic beacon and maritime radio dual-mode positioning method for marine electronic anchors provided in this application adopts the following technical solution: A dual-mode positioning method for an underwater electronic anchor using an acoustic beacon and surface radio, applicable to an underwater acoustic beacon, a surface radio module, and a surface monitoring terminal, wherein communication connections are established between the underwater acoustic beacon, the surface radio module, and the surface monitoring terminal, respectively, including: The underwater acoustic beacon collects real-time acoustic environmental parameters of the surrounding water body, and generates a target positioning acoustic signal based on the real-time acoustic environmental parameters, and then sends the target positioning acoustic signal to the water surface monitoring terminal. After sending the status information and real-time acoustic environment parameters of the underwater acoustic beacon to the surface radio module, the surface radio module then sends the status information, real-time acoustic environment parameters, and the location information of the surface radio module to the surface monitoring terminal. By correcting the target positioning acoustic signal based on real-time acoustic environment parameters in the water surface monitoring terminal, and calculating the geographical location of the underwater acoustic beacon based on the location information, the credibility of the corrected target positioning acoustic signal and geographical location is verified according to the status information, and the positioning information is output based on the verification results.

[0005] Furthermore, the real-time acoustic environmental parameters include temperature, salinity, and depth. The steps for generating target localization acoustic signals based on these real-time acoustic environmental parameters include: Based on temperature, salinity, and depth, the real-time sound velocity of the water layer where the underwater acoustic beacon is located is calculated. Based on real-time and historical sound speed profile data, the trend of sound speed profile change from underwater acoustic beacon to the preset sound propagation path is predicted. Matching is performed based on the trend of sound velocity profile changes to obtain the target signal modulation scheme and the target channel center frequency; Based on the target signal modulation method and the target channel center frequency, a target positioning acoustic signal is generated.

[0006] Furthermore, based on real-time and historical sound speed profile data, the steps for predicting the trend of sound speed profile changes along the preset sound propagation path from the underwater acoustic beacon include: Determine the starting sound velocity of the preset sound propagation path based on the geometric path of the preset sound propagation path and the real-time sound velocity. By combining historical sound velocity profile data and the starting sound velocity, the predicted sound velocity at each spatial point on the preset sound propagation path in the future time period can be calculated. Based on the predicted sound speed, the spatial gradient of the sound speed along the preset sound propagation path is calculated. Based on the spatial gradient of sound speed, the trend of sound speed variation with distance and depth along the preset sound propagation path is obtained by quantization.

[0007] Furthermore, based on the target signal modulation scheme and the target channel center frequency, the steps for generating the target positioning acoustic signal include: Based on the target signal modulation method, the source data on the underwater acoustic beacon is modulated to generate a baseband modulated signal; After converting the baseband modulation signal to the center frequency of the target channel to generate the carrier modulation signal, a guard interval is inserted into the carrier modulation signal according to the modulation method of the target signal to generate the initial acoustic signal. Based on the preset propagation delay deviation along the preset sound propagation path, the transmission phase of the initial acoustic signal is compensated and adjusted to generate the target positioning acoustic signal.

[0008] Furthermore, the steps for correcting the target localization acoustic signal based on real-time acoustic environment parameters include: Based on temperature, salinity, and depth, the real-time sound velocity of the water layer where the underwater acoustic beacon is located is calculated. Based on the real-time sound velocity, the propagation delay deviation between the underwater acoustic beacon and the surface monitoring terminal is calculated; Based on the propagation delay deviation, the timing adjustment amount of the transmission time of the target positioning acoustic signal is determined. Then, the transmission time is adjusted according to the timing adjustment amount to generate the corrected target positioning acoustic signal.

[0009] Furthermore, the steps for calculating the geographical location of the underwater acoustic beacon based on location information include: After determining the geographical coordinates of the surface radio module based on the location information, the relative position vector of the underwater acoustic beacon relative to the surface radio module is calculated based on the corrected target positioning acoustic signal. By combining the relative position vector and geographic coordinates, the geographical location of the underwater radio module can be obtained.

[0010] Furthermore, the steps for verifying the credibility of the corrected target positioning acoustic signal and geographical location based on the state information include: Based on the battery voltage and internal temperature parameters in the status information, the operating status level of the underwater radio module is determined. The system calculates the transmission stability of the target positioning acoustic signal after correction based on the working level, and determines the reliability level of the geographical location based on the transmission stability. The output includes the verification results of transmission stability and reliability level.

[0011] Beneficial effects achieved: This application provides a dual-mode positioning method for an underwater electronic anchor using both acoustic beacons and surface radio. This method is applied to an underwater acoustic beacon, a surface radio module, and a surface monitoring terminal. Communication connections are established between the underwater acoustic beacon, the surface radio module, and the surface monitoring terminal. The method includes: collecting real-time acoustic environmental parameters of the surrounding water body via the underwater acoustic beacon; generating a target positioning acoustic signal based on the real-time acoustic environmental parameters; and sending the target positioning acoustic signal to the surface monitoring terminal. After sending the status information of the underwater acoustic beacon and the real-time acoustic environmental parameters to the surface radio module, the surface radio module sends the status information, the real-time acoustic environmental parameters, and the location information of the surface radio module to the surface monitoring terminal. At the surface monitoring terminal, the target positioning acoustic signal is corrected based on the real-time acoustic environmental parameters, and the geographical location of the underwater acoustic beacon is calculated based on the location information. The reliability of the corrected target positioning acoustic signal and geographical location is verified based on the status information, and positioning information is output based on the verification results.

[0012] In this application, underwater acoustic beacons are used to collect real-time acoustic environmental parameters of the surrounding water and generate target positioning acoustic signals accordingly. This ensures that the emitted target acoustic signals are optimized for factors affecting propagation speed and path, such as the sound speed and temperature of the current water body, thus reducing fundamental errors caused by mismatches between fixed signal patterns and the environment. Next, the status information and the aforementioned real-time acoustic environmental parameters are synchronously sent to a surface radio module, which then uploads the acquired position information to the surface monitoring terminal, ensuring that all data used for calculation by the surface monitoring terminal is accurate and reliable. Real-time and collaborative; finally, at the surface monitoring end, the received real-time acoustic environment parameters are used to correct the target positioning acoustic signal, which can directly compensate for the sound ray bending and time delay deviation caused by the change in sound speed profile when the sound wave propagates in the actual water body, thereby obtaining a more accurate relative distance and orientation between the underwater acoustic beacon and the surface monitoring end. Combined with the location information provided by the surface radio module, the geographical location of the underwater acoustic beacon is calculated, and the credibility verification based on the status information can identify and mark abnormal data, thereby ensuring the accuracy of the output positioning information. Attached Figure Description

[0013] Figure 1 This is a flowchart illustrating the steps of a dual-mode positioning method for an acoustic beacon and a surface radio signal of a marine electronic anchor, as described in this application. Figure 2 This is a flowchart illustrating the steps involved in generating target localization acoustic signals based on real-time acoustic environment parameters in this application. Figure 3 This is a flowchart illustrating the calculation steps in step S30 of this application. Detailed Implementation

[0014] The following combination Figures 1 to 3 This application will be described in further detail.

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0016] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0017] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0018] This application discloses a dual-mode positioning method for acoustic beacons and maritime radio signals of an ocean electronic anchor.

[0019] Please refer to Figure 1 The dual-mode positioning method for acoustic beacons and surface radio signals of marine electronic anchors proposed in this embodiment includes steps S10~S30: Step S10: Collect real-time acoustic environment parameters of the surrounding water body through underwater acoustic beacons, generate target positioning acoustic signals based on real-time acoustic environment parameters, and then send the target positioning acoustic signals to the water surface monitoring terminal.

[0020] In this step, underwater acoustic beacons are enabled to actively sense and adapt to their real-time marine acoustic environment, optimizing the entire positioning process from the source of signal transmission. By collecting real-time acoustic environmental parameters such as temperature, salinity, and depth, and generating target positioning acoustic signals based on these parameters, the transmitted target positioning acoustic signals can be initially matched and optimized to the actual sound velocity profile and channel conditions of the current water body. This proactively reduces the inherent distortion and interference faced by the target positioning acoustic signals when propagating in complex underwater acoustic channels, laying the foundation for subsequent signal correction and calculation at the surface monitoring end.

[0021] In this embodiment, the temperature, salinity, and depth sensors integrated on the underwater acoustic beacon directly measure the seawater in the water layer where the underwater acoustic beacon is located, thereby simultaneously acquiring three real-time acoustic environmental parameters: temperature, salinity, and depth. This provides the unique and necessary data input for subsequent real-time calculation of the sound velocity in the water layer where the underwater acoustic beacon is located, thus ensuring the real-time response capability of the dual-mode positioning system of this application to dynamic changes in the marine acoustic environment from the source of information perception. At the same time, based on the three real-time acoustic environmental parameters collected, a target positioning acoustic signal is generated. The generated target positioning acoustic signal is directly encapsulated into a data packet and sent to the surface monitoring terminal through the communication connection between the underwater acoustic beacon and the surface monitoring terminal.

[0022] Step S20: After sending the status information and real-time acoustic environment parameters of the underwater acoustic beacon to the surface radio module, the status information, real-time acoustic environment parameters, and location information of the surface radio module are sent to the surface monitoring terminal based on the surface radio module.

[0023] The underwater acoustic beacon first encapsulates its own status information and real-time acoustic environmental parameters collected by a temperature, salinity, and depth sensor into a data packet, which is then transmitted to the surface radio module via an underwater acoustic communication link. Next, upon receiving this data packet, the surface radio module fuses and encapsulates it with its own location information obtained via a BeiDou or GPS module, and then transmits it to the surface monitoring terminal via a radio communication link (such as BeiDou short message service, satellite communication, or mobile network). In this step, the real-time acoustic environmental parameters of the underwater acoustic beacon, its own status information, and the location information of the surface radio module are converged to the surface monitoring terminal in real time and collaboratively. This provides the necessary and complete fused data foundation for the subsequent surface monitoring terminal to use real-time acoustic environmental parameters to correct the target positioning acoustic signal, calculate the geographical location of the underwater acoustic beacon by combining the surface location, and assess the reliability of the corrected target positioning acoustic signal and geographical location based on the equipment status.

[0024] Step S30: In the water surface monitoring terminal, after correcting the target positioning acoustic signal based on real-time acoustic environment parameters and calculating the geographical location of the underwater acoustic beacon based on the location information, the credibility of the corrected target positioning acoustic signal and geographical location is verified according to the status information, and the positioning information is output according to the verification results.

[0025] The correction of the target positioning acoustic signal based on received real-time acoustic environmental parameters at the surface monitoring end utilizes real-time acoustic environmental parameters obtained from underwater acoustic beacons to compensate for the time delay and waveform distortion caused by the propagation of the target positioning acoustic signal in complex waterways. This results in a more accurate relative relationship between the underwater acoustic beacon and the surface monitoring end. Simultaneously, based on the location information provided by the surface radio module, this relative relationship is calculated into the geographical location of the underwater acoustic beacon. This process deeply integrates underwater acoustic relative positioning and radio absolute positioning technologies. Then, the reliability of the corrected target positioning acoustic signal and the calculated geographical location is verified based on state information. The state information of the surface radio module itself serves as an intrinsic basis for judging signal quality and the reliability of positioning results, identifying and filtering out deviations that may be caused by equipment malfunctions. Ultimately, this series of operations achieves the effect of systematically outputting optimized positioning information with reliability assessment through the triple guarantee of "environmental correction - absolute calculation - state verification," thus ensuring that the positioning results are not only accurate but also reliable and usable in complex marine applications.

[0026] It should be noted that in this embodiment, in step S10, the target positioning acoustic signal of the underwater acoustic beacon is directly sent to the surface monitoring end, while the status information and real-time acoustic environment parameters of the underwater acoustic beacon are sent to the surface monitoring end through the surface radio module. This split-path transmission design is based on the different technical characteristics and transmission requirements of the two signals. The target positioning acoustic signal carries precise time delay information and is used for direct positioning calculation. It must be sent directly to the hydrophone array of the surface monitoring end through a dedicated high-fidelity underwater acoustic channel to ensure measurement accuracy. On the other hand, the status information and real-time acoustic environment parameters are small digital packets with relatively relaxed real-time requirements. They can be uploaded to the surface radio module through underwater acoustic communication and then reliably transmitted back using its inherent long-range radio communication capability. This ensures that the high-fidelity target positioning acoustic signal reaches the surface monitoring end directly through a dedicated underwater acoustic link to guarantee core measurement accuracy. At the same time, the data packets are transmitted back through an underwater acoustic-radio relay link to achieve reliable remote transmission, thereby optimizing the data transmission path and resource utilization of the entire dual-mode positioning system.

[0027] In one feasible implementation, refer to Figure 2 As shown, step S10 may specifically include steps S11 to S14: Step S11: Based on temperature, salinity, and depth, calculate the real-time sound velocity of the water layer where the underwater acoustic beacon is located.

[0028] The underwater acoustic beacon synchronously measures temperature, salinity, and depth using its integrated temperature, salinity, and depth sensors. These measurements are then used as input parameters to calculate the speed of sound using an empirical formula that describes the relationship between sound wave propagation speed in the ocean and temperature, salinity, and depth. The specific empirical formula for the speed of sound is shown below: in, For real-time sound speed; 1448.96 is a constant term, representing the reference value of sound speed under standard reference conditions (typically close to temperature T=0℃, salinity S=35PSU, depth D=0 meters); 4.591, and These are the temperature term coefficients, controlling the temperature T and the square of the temperature, respectively. and the cube of temperature The weight of the impact on real-time sound speed, with its positive or negative sign, reflects that the real-time sound speed does not change with temperature in a simple linear relationship; 1.34 is the salinity coefficient, which controls the weight of the impact of salinity deviation from the standard value (S-35) on real-time sound speed. and These are the depth term coefficients, controlling depth D and the square of depth, respectively. The weights of the impact on real-time sound velocity describe the effect of increased hydrostatic pressure on increasing real-time sound velocity. and These are the cross-term coefficients, used to characterize the interactive effects of temperature and salinity, and temperature and depth, on real-time sound speed.

[0029] The above formula comprehensively reflects the influence of seawater temperature, salinity, and water pressure (represented by depth) on the speed of sound propagation. The direct calculation of the formula outputs a real-time sound velocity with clear physical meaning. This calculated real-time sound velocity represents the speed of sound propagation in the water layer where the underwater acoustic beacon is located under current environmental conditions. It provides the dual-mode positioning system with the crucial environmental benchmark necessary for all subsequent signal processing and calculations—the real-time sound velocity at the sound source. This allows the dual-mode positioning system to initiate subsequent sound velocity profile prediction and propagation delay compensation based on the true and accurate acoustic environment conditions of the water layer where the underwater acoustic beacon is located, rather than historical data or statistical averages. This fundamentally improves the timeliness and accuracy of environmental perception, laying a reliable data foundation for counteracting sound ray bending and ensuring positioning accuracy.

[0030] Step S12: Based on real-time sound speed and historical sound speed profile data, predict the trend of sound speed profile change from the underwater acoustic beacon to the preset sound propagation path.

[0031] It should be noted that historical sound velocity profile data refers to a historical dataset of sound velocity variations with depth and horizontal position accumulated through long-term observation of the target sea area; the preset sound propagation path refers to a predefined spatial route for sound wave propagation from the location of the underwater acoustic beacon to the hydrophone array at the surface monitoring end.

[0032] Based on the real-time sound velocity calculated from underwater acoustic beacons and combined with historical sound velocity profile data reflecting the typical hydrological structure of the sea area, the sound velocity values ​​and their variation patterns at various points along the preset sound propagation path are inferred, i.e., the sound velocity profile variation trend. This expands the single point-like real-time sound velocity into a trend-based path acoustic environment forecast, thereby quantifying the main potential causes of sound ray bending and signal distortion. This provides a direct and quantitative decision basis for subsequent steps to select the anti-multipath target signal modulation method and the target channel center frequency. It enables the dual-mode positioning system to optimize the signal waveform in advance for specific sound velocity gradients and rates of change along the preset sound propagation path in future time periods, thereby suppressing interference caused by sound velocity profile changes before the target positioning acoustic signal is transmitted, effectively improving the adaptability and propagation reliability of the target positioning acoustic signal in complex time-varying marine channels.

[0033] Furthermore, step S12 may include steps S121 to S124: Step S121: Determine the starting sound velocity of the preset sound propagation path based on the geometric path of the preset sound propagation path and the real-time sound velocity.

[0034] It should be noted that the geometric path of the preset sound propagation path is determined by its starting point (i.e., the position of the underwater acoustic beacon), the ending point (i.e., the position of the hydrophone), and possible propagation direction constraints.

[0035] By directly assigning the real-time sound velocity value to the geometric starting point of the preset sound propagation path, the starting sound velocity is determined, establishing a spatiotemporal reference origin for the entire sound velocity profile prediction. This means anchoring the sound velocity state at the starting point of the geometric path to the current measurement result at the underwater acoustic beacon, thereby ensuring that subsequent calculations based on this starting sound velocity to extrapolate the sound velocity change trend along the preset sound propagation path have real and reliable initial conditions. This fundamentally avoids the systematic bias introduced by using historical or statistical sound velocity values ​​as the prediction starting point.

[0036] Step S122: Combining historical sound velocity profile data and starting sound velocity, the predicted sound velocity of each spatial point on the preset sound propagation path in the future time period is calculated.

[0037] Using the starting sound velocity determined in the above steps as the absolute benchmark for the current measurement, and taking the changes in sound velocity with depth and horizontal position in the sea area as reflected in historical sound velocity profile data as the background field, the determined starting sound velocity is compared with the historical sound velocity at the corresponding position of the starting point in the historical sound velocity profile data. A sound velocity correction amount representing the deviation between the current environment and the historical average state is calculated. Then, using the current starting sound velocity as the absolute benchmark, the sound velocity distribution along the entire preset propagation path in the background field of the historical sound velocity profile data is translated and scaled as a whole, so that the sound velocity value at the starting point is consistent with the current starting sound velocity, while maintaining the relative gradient and change pattern of the hydrological structure of the sea area inherent in the historical data. On this basis, combined with the periodic changes in the sound velocity of the sea area over time... The system extrapolates the adjusted spatial sound velocity field to reflect the regular changes that may occur from the current moment to the future. Finally, through spatial interpolation along the preset sound propagation path, it outputs the sound velocity value of each spatial location on the preset sound propagation path in the future time period after real-time sound velocity correction and time correction. This completes the calculation from single-point real-time measurement to the prediction of future sound velocity along the preset sound propagation path, generating a continuous, spatially covered predicted sound velocity. This provides a data foundation for the next step of calculating the spatial gradient and trend of sound velocity profile changes. It enables the dual-mode positioning system to optimize signal design based on the overall prediction of the path environment rather than single-point information, thereby significantly improving the accuracy and foresight of adaptive processing of complex time-varying marine acoustic channels.

[0038] Among them, periodicity mainly refers to the diurnal and seasonal variations with predictable and repeatable characteristics driven by solar radiation, air-sea heat exchange and climate models. Its core manifestation is the diurnal cycle of surface seawater temperature within a day and the alternation of warm and cold temperatures within a year. Spatial interpolation refers to the process of estimating the sound velocity values ​​of all other continuous spatial points on a preset sound propagation path based on the historical sound velocity at known discrete spatial points through methods such as linear interpolation and spline interpolation.

[0039] Step S123: Based on the predicted sound speed, calculate the spatial gradient of the sound speed along the preset sound propagation path.

[0040] Using the predicted sound velocity at each discrete spatial point on a preset sound propagation path as input data, the rate and direction of change of the predicted sound velocity in space are quantitatively described by calculating the ratio of the change in predicted sound velocity between adjacent spatial points on the preset sound propagation path to the corresponding spatial distance. This includes calculating the horizontal gradient of the predicted sound velocity along the horizontal propagation direction and the vertical gradient of the sound velocity along the depth direction, thereby obtaining a spatial gradient of sound velocity that characterizes the refraction effect caused by the non-uniformity of sound velocity in the preset sound propagation path.

[0041] By converting the predicted sound velocity along the preset sound propagation path into a sound velocity spatial gradient that can be directly used to guide signal design, this sound velocity spatial gradient quantitatively reveals the degree and direction of the bending of the sound ray, thus providing a basis for decision-making in the next step. This enables the dual-mode positioning system to select the target signal modulation method and target channel center frequency that best resists the corresponding multipath interference and waveform distortion based on the predicted sound velocity.

[0042] Step S124: Quantize the sound speed spatial gradient to obtain the trend of sound speed profile variation with distance and depth along the preset sound propagation path.

[0043] The absolute value of the quotient obtained by dividing the real-time sound speed value propagating in the current water layer by the vertical sound speed gradient at that point is the radius of curvature of the sound ray at that point. This radius of curvature directly quantifies the severity of the sound ray's bending due to sound speed stratification. Simultaneously, path integrals are performed on the horizontal and vertical sound speed gradients along the preset sound propagation path. The integral result of the horizontal sound speed gradient reflects the cumulative change in the predicted sound speed along the propagation direction, while the integral result of the vertical sound speed gradient describes the total variation of the sound speed in the depth dimension. These two integral results are combined with the actual trajectory length of the sound ray calculated based on the radius of curvature to further synthesize the theoretical time delay deviation of the signal propagating along the curved path compared to the straight path. Then, the radius of curvature, cumulative change, total variation, and theoretical time delay deviation are integrated to generate a dataset that continuously characterizes the amplitude and pattern of sound speed changes with propagation distance and depth as independent variables. This dataset completes the quantification of the trend of sound speed profile changes.

[0044] By integrating the spatial gradient of sound velocity, which reflects the local rate of change, obtained from the previous steps, into a trend description that can fully describe the acoustic characteristics of the entire preset sound propagation path, a structured environmental feature input that can be directly used for searching or decision-making is provided for the next step. This allows the target localization acoustic signal generation stage to select the optimal target signal modulation method and target channel center frequency based on this quantized trend feature.

[0045] Step S13: Match the target signal modulation scheme and the target channel center frequency based on the trend of sound speed profile changes.

[0046] The quantized sound velocity profile change trend is compared and searched in a preset signal parameter library. This preset signal parameter library stores the optimal signal modulation method corresponding to different sound velocity profile change modes. For example, under the path trend of large sound velocity gradient and significant multipath effect, a modulation method with strong anti-multipath capability, such as orthogonal frequency division multiplexing or spread spectrum modulation, is matched, as well as the most suitable channel center frequency, such as the center frequency is matched in a specific low frequency band of the environmental noise spectrum or a frequency band with small sound propagation loss.

[0047] Through this matching based on characteristic parameters, the system automatically outputs the signal modulation method and channel center frequency that best match the current preset sound propagation path, enabling the generated target positioning acoustic signal to actively suppress adverse effects such as multipath interference and frequency-selective fading caused by uneven sound speed.

[0048] Step S14: Based on the target signal modulation method and the target channel center frequency, generate the target positioning acoustic signal.

[0049] Based on the determined target signal modulation method and target channel center frequency, the raw source data of the underwater acoustic beacon is modulated, frequency-converted, and waveform-shaped to ultimately generate a target positioning acoustic signal with a specific modulation structure and carrying frequency. Its function is to ensure that the target positioning acoustic signal to be transmitted is strictly consistent with the optimal anti-interference scheme for the current sound velocity profile change trend in terms of modulation format and spectral position. This makes the generated target positioning acoustic signal a physical entity for positioning that has been environmentally adaptively optimized. From the beginning of transmission, it has the ability to resist predicted multipath interference and adapt to frequency-selective fading of specific channels. Thus, in the complex real-time marine acoustic channel, it can maintain high signal integrity and detectability, laying a solid foundation for subsequent high-precision signal arrival time measurement and positioning calculation at the surface monitoring end.

[0050] Furthermore, step S14 may include steps S141 to S143: Step S141: Based on the target signal modulation method, the source data on the underwater acoustic beacon is modulated to generate a baseband modulation signal.

[0051] The source data (such as identification codes, synchronization headers, or sensor data packets) pre-stored or generated in real time within the underwater acoustic beacon is used as the raw digital sequence to be transmitted. According to the specific rules defined by the determined target signal modulation scheme, this raw digital sequence undergoes symbol mapping and waveform shaping. Specifically, based on the constellation diagram defined by the target signal modulation scheme (such as binary phase-shift keying), each bit group of a preset length in the raw digital sequence is uniquely mapped to a complex symbol with a specific amplitude and phase. This complex symbol sequence is then discretely sampled at symbol period intervals to generate a discrete-time symbol sequence. This discrete-time symbol sequence is then passed through a pulse shaping filter (such as a raised cosine filter) with a specific roll-off coefficient and bandwidth. The pulse shaping filter smooths the waveform and limits the bandwidth of each discrete-time symbol, eliminating interference between discrete-time symbols and ensuring that the signal energy is concentrated within the baseband frequency band. The final output is a baseband modulated signal that varies continuously in the time domain, with its spectrum centered at zero frequency, and satisfies the preset bandwidth constraints.

[0052] By converting the source information into a baseband modulated signal with a specific modulation structure suitable for transmission in a physical channel, the core capability of the subsequently generated target positioning acoustic signal to resist multipath interference, noise, and frequency-selective fading is directly determined. This provides the underlying signal foundation for subsequent upconversion to the target channel center frequency and the final formation of a transmittable target positioning acoustic signal.

[0053] Step S142: After converting the baseband modulation signal to the center frequency of the target channel and generating the carrier modulation signal, a guard interval is inserted into the carrier modulation signal according to the target signal modulation method to generate the initial acoustic signal.

[0054] The generated baseband modulation signal is multiplied by a complex carrier (i.e., a complex exponential function) with a frequency equal to the center frequency of the target channel by complex multiplication, thereby achieving spectrum shifting. Then, the real part of the product is taken to obtain a real bandpass signal with a center frequency at the center frequency of the target channel. This real bandpass signal is the carrier modulation signal.

[0055] Subsequently, based on the frame structure or protocol specification corresponding to the target signal modulation method, a blank period without information or a cyclic prefix at the end of the copied signal is inserted into each symbol of the carrier modulation signal as a guard interval to generate the initial acoustic signal.

[0056] By placing the modulated baseband signal onto the target channel center frequency selected through environmental matching and transmitting it, and by inserting a guard interval to effectively resist inter-symbol interference caused by multipath effects in the underwater acoustic channel, an initial acoustic signal with correct spectral position and time-domain protection structure is generated.

[0057] Step S143: Based on the preset propagation delay deviation on the preset sound propagation path, the transmission phase of the initial acoustic signal is compensated and adjusted to generate the target positioning acoustic signal.

[0058] It should be noted that the preset propagation delay deviation refers to the additional time difference that occurs when the sound wave propagates from the underwater acoustic beacon along a preset, actually curved sound propagation path to the hydrophone, based on the prediction of the trend of sound speed profile changes, compared to the time difference caused by propagation along an ideal straight path.

[0059] During compensation adjustment, firstly, based on the preset propagation delay deviation and the target channel center frequency, a corresponding phase compensation amount is calculated. This phase compensation amount is equal to the product of the preset propagation delay deviation and the angular frequency corresponding to the target channel center frequency. Then, each signal amplitude value of the initial acoustic signal is uniformly multiplied by the complex rotation factor of the phase compensation amount in the complex domain, which is equivalent to performing a linear translation on the entire phase spectrum of the initial acoustic signal, thereby generating a target positioning acoustic signal whose carrier phase has been pre-adjusted at the transmission time.

[0060] By applying a pre-distortion opposite to the preset propagation delay deviation to the target positioning acoustic signal before its transmission, most of the expected phase distortion that will occur when the sound wave propagates in complex time-varying water bodies is actively canceled. This makes the phase state of the target positioning acoustic signal reaching the hydrophone after actual propagation closer to the ideal state without distortion. This greatly facilitates the accurate measurement of the arrival time of the target positioning acoustic signal at the water surface monitoring end, and fundamentally improves the accuracy of subsequent time delay estimation and positioning calculation.

[0061] In one feasible implementation, refer to Figure 3 As shown, step S30 may specifically include steps S31 to S37: Step S31: Based on temperature, salinity, and depth, calculate the real-time sound velocity of the water layer where the underwater acoustic beacon is located.

[0062] The specific calculation process of step S31 is the same as that of step S11, so it will not be repeated here.

[0063] Step S32: Calculate the propagation time deviation between the underwater acoustic beacon and the surface monitoring terminal based on the real-time sound speed.

[0064] By using the deployment coordinates of the underwater acoustic beacon and the real-time coordinates of the hydrophone, the geometric straight-line path length between them is calculated. A pre-defined average seawater speed representing the typical acoustic conditions of the sea area is obtained. The geometric straight-line path length is then divided by the average seawater speed to obtain the theoretical propagation delay. Simultaneously, based on the real-time speed calculated in the above steps, and combined with the trend of the speed profile along the preset sound propagation path, the predicted total sound path length of the sound wave propagating along the actual curved path is calculated. This total sound path length is then divided by the corresponding average sound speed along the path to obtain the predicted actual propagation delay. Finally, the difference between the calculated predicted actual propagation delay and the theoretical propagation delay is calculated; the difference is the propagation delay deviation.

[0065] By converting real-time sound velocity into a quantized time error that can be directly used to guide the timing of acoustic signal transmission for target positioning, a precise input is provided for the next step. This enables the dual-mode positioning system to actively compensate for propagation delays caused by environmental changes through pre-adjusted transmission timing, achieving a key link in high-precision synchronization and positioning.

[0066] Step S33: Based on the propagation delay deviation, determine the timing adjustment amount of the transmission time of the target positioning acoustic signal, adjust the transmission time according to the timing adjustment amount, and generate the corrected target positioning acoustic signal.

[0067] The propagation delay deviation calculated in the above steps is directly negative, and the negative value is defined as the timing adjustment amount. Mathematically, this operation means that in order to compensate for the additional delay that the signal will experience on the propagation path, the signal transmission time needs to be advanced accordingly.

[0068] Next, based on the timing adjustment amount, the planned launch time of the target positioning acoustic signal is modified, that is, the adjustment amount is subtracted from the original launch time, thereby determining an advanced actual launch time.

[0069] Finally, the drive signal transmitting device sends out the target positioning acoustic signal at the new actual transmission time. The signal transmitted at this time is the corrected target positioning acoustic signal.

[0070] By actively canceling the propagation delay caused by changes in sound velocity profile and sound ray bending before the target positioning acoustic signal is transmitted, the time when the target positioning acoustic signal arrives at the hydrophone after propagating through the actual underwater acoustic channel is closer to the theoretical arrival time under the assumption of uniform medium and straight-line propagation. This greatly reduces the systematic error introduced by environmental time-varying factors when the water surface monitoring end measures the arrival time of the target positioning acoustic signal.

[0071] Step S34: After determining the geographical coordinates of the surface radio module based on the location information, the relative position vector of the underwater acoustic beacon relative to the surface radio module is calculated based on the corrected target positioning acoustic signal.

[0072] The system directly reads and parses the location information obtained in real time via satellite positioning from the BeiDou or GPS module integrated in the underwater radio module. This location information typically includes latitude, longitude, and elevation. The extracted latitude, longitude, and elevation are then substituted into the geographic coordinate transformation formula shown below: in, Represents the three-dimensional coordinates in the target coordinate system; This indicates the latitude, longitude, and elevation of the location information obtained by satellite positioning in the original coordinate system. This represents the offset required to translate from the original coordinate system to the target coordinate system; K represents the scale parameter (or scaling factor), usually expressed in ppm (parts per million), used to compensate for scale differences between the two coordinate systems; , and These are rotation parameters, representing the rotation angles around the X, Y, and Z axes, respectively; , and For rotation matrices corresponding to rotations about the X, Y, and Z axes respectively, they are usually simplified to the following under small-angle approximations: After directly determining the geographic coordinates of the surface radio module in the current sea area through the coordinate system transformation based on the location information, the surface monitoring terminal uses its hydrophone array to measure the time difference or phase difference of the signal arriving at different array elements based on the corrected target positioning acoustic signal. Combining the known geometry of the hydrophone array and the real-time sound speed, the direction and straight-line distance of the underwater acoustic beacon relative to the hydrophone array are determined. The direction and straight-line distance are then combined into a spatial vector pointing from the hydrophone array reference point to the underwater acoustic beacon. This spatial vector represents the relative position vector of the underwater acoustic beacon relative to the surface radio module.

[0073] By bridging and fusing the geographic coordinates provided by satellites with the location of the underwater acoustic beacon relative to the direction and straight-line distance of the hydrophone array, an offset with clear physical meaning and geographic reference is provided for the next step, thus realizing the core of the conversion from relative positioning to high-precision absolute geolocation.

[0074] Step S35: Combine the relative position vector and geographic coordinates to obtain the geographic location of the underwater radio module.

[0075] Using geographic coordinates as the absolute reference point in three-dimensional space, and the relative position vector of the underwater acoustic beacon relative to this absolute reference point calculated in the same step as the spatial offset, the three components of the relative position vector (i.e., the offset in the longitude, latitude and depth directions) are added to the three-dimensional geographic coordinates of the absolute reference point through three-dimensional vector addition to obtain the geographical location of the underwater radio module.

[0076] Specifically, this operation involves directly superimposing the geometric spatial relationship represented by the relative position vector onto the known geographic coordinates within a unified coordinate system framework. This achieves seamless integration of the relative geometric relationship obtained by underwater acoustic measurement technology with the absolute geographic coordinates provided by satellite positioning technology, thereby outputting the latitude, longitude, and depth coordinates of the underwater acoustic beacon in the sea area. This completes the crucial transformation from relative position to a geographic location that can be directly plotted on a map, enabling the underwater portion of the marine electronic anchor to achieve high-precision geospatial positioning.

[0077] Step S36: Based on the battery voltage and internal temperature parameters in the status information, the operating status level of the underwater radio module is obtained.

[0078] The system receives and parses status information from underwater acoustic beacons, extracts battery voltage and internal temperature parameters, and compares these two values ​​with a preset threshold table that defines the corresponding value ranges for different levels such as "normal," "warning," and "abnormal." By determining which threshold range each value falls into, a preliminary level is determined for the battery voltage and internal temperature parameters. Then, based on a set of preset decision rules, for example, if both are normal, the "normal" level is output; if either reaches the warning level, the "caution" level is output; and if either reaches the abnormal level, the "abnormal" level is output. In this way, the two preliminary levels are comprehensively judged, mapped, and a unified working status level is output.

[0079] By transforming state information into an intuitive and standardized health indicator, an objective and quantitative decision input is provided for the next step. This enables the dual-mode positioning system to correlate state information with the quality of positioning information and the reliability of the final result, thereby achieving an intrinsic assessment of the reliability of the positioning system output.

[0080] Step S37: Based on the working level, determine the transmission stability of the corrected target positioning acoustic signal, and based on the transmission stability, determine the reliability level of the geographical location, and output the verification result including transmission stability and reliability level.

[0081] The operating status level is taken as input, and a preset mapping rule is used to directly determine and correct the transmission stability level of the target positioning acoustic signal. For example, the normal level is directly mapped to high transmission stability, the attention level is mapped to medium transmission stability, and the abnormal level is mapped to low transmission stability.

[0082] Next, the newly obtained transmission stability level is used as a new input, and a preset mapping rule is applied again, such as mapping high transmission stability to high reliability level, medium transmission stability to medium reliability level, and low transmission stability to low reliability level, to determine the reliability level of the geographical location.

[0083] Finally, a data structure or standardized message containing two specific fields—transmission stability and geographic location reliability level—and their judgment results is output as the verification result. This establishes a complete evaluation chain from device hardware status to signal quality and then to the reliability of positioning results. This evaluation is quantified into intuitive level information, enabling dual-mode positioning systems or operators to make quick and objective judgments on the inherent reliability of the current positioning results without relying on external testing. This provides crucial reliability basis for critical decisions on whether to adopt the positioning information in complex underwater operations.

[0084] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A dual-mode positioning method for marine electronic anchors using acoustic beacons and surface radio, characterized in that, The dual-mode positioning method of the marine electronic anchor, combining acoustic beacons and surface radio, is applied to underwater acoustic beacons, surface radio modules, and surface monitoring terminals. Communication connections are established between the underwater acoustic beacons, the surface radio modules, and the surface monitoring terminals, including: The underwater acoustic beacon collects real-time acoustic environmental parameters of the surrounding water body, generates a target positioning acoustic signal based on the real-time acoustic environmental parameters, and then sends the target positioning acoustic signal to the water surface monitoring terminal. After sending the status information of the underwater acoustic beacon and the real-time acoustic environment parameters to the surface radio module, the surface radio module then sends the status information, the real-time acoustic environment parameters, and the location information of the surface radio module to the surface monitoring terminal. By correcting the target positioning acoustic signal based on the real-time acoustic environment parameters in the water surface monitoring terminal, and calculating the geographical location of the underwater acoustic beacon based on the location information, the credibility of the corrected target positioning acoustic signal and the geographical location is verified according to the status information, and the positioning information is output according to the verification result.

2. The dual-mode positioning method for acoustic beacons and surface radio communication of a marine electronic anchor according to claim 1, characterized in that, The real-time acoustic environment parameters include temperature, salinity, and depth. The step of generating a target localization acoustic signal based on the real-time acoustic environment parameters includes: Based on the temperature, salinity, and depth, the real-time sound velocity of the water layer where the underwater acoustic beacon is located is calculated. Based on the real-time and historical sound speed profile data, the trend of sound speed profile change from the underwater acoustic beacon to the preset sound propagation path is predicted; The target signal modulation scheme and the target channel center frequency are obtained by matching the change trend of the sound speed profile. Based on the target signal modulation scheme and the target channel center frequency, the target positioning acoustic signal is generated.

3. The dual-mode positioning method for acoustic beacons and surface radio communication of a marine electronic anchor according to claim 2, characterized in that, The step of predicting the trend of sound speed profile change along the preset sound propagation path from the underwater acoustic beacon based on the real-time and historical sound speed profile data includes: The starting speed of the preset sound propagation path is determined based on the geometric path of the preset sound propagation path and the real-time sound speed. By combining the historical sound velocity profile data and the starting sound velocity, the predicted sound velocity of each spatial point on the preset sound propagation path in the future time period is calculated. Based on the predicted sound speed, the spatial gradient of the sound speed along the preset sound propagation path is calculated; Based on the spatial gradient of sound speed, the trend of sound speed profile variation with distance and depth along the preset sound propagation path is obtained by quantization.

4. The dual-mode positioning method for acoustic beacons and surface radio communication of a marine electronic anchor according to claim 2, characterized in that, The step of generating the target positioning acoustic signal based on the target signal modulation scheme and the target channel center frequency includes: Based on the target signal modulation method, the signal source data on the underwater acoustic beacon is modulated to generate a baseband modulated signal; After converting the baseband modulation signal to the center frequency of the target channel to generate a carrier modulation signal, a guard interval is inserted into the carrier modulation signal according to the target signal modulation method to generate an initial acoustic signal. The transmission phase of the initial acoustic signal is compensated and adjusted according to the preset propagation delay deviation on the preset sound propagation path to generate the target positioning acoustic signal.

5. The dual-mode positioning method for acoustic beacons and surface radio communication of a marine electronic anchor according to claim 2, characterized in that, The step of correcting the target positioning acoustic signal based on the real-time acoustic environment parameters includes: Based on the temperature, salinity, and depth, the real-time sound velocity of the water layer where the underwater acoustic beacon is located is calculated. Based on the real-time sound velocity, the propagation delay deviation between the underwater acoustic beacon and the surface monitoring terminal is calculated; Based on the propagation delay deviation, after determining the timing adjustment amount of the transmission time of the target positioning acoustic signal, the transmission time is adjusted according to the timing adjustment amount to generate the corrected target positioning acoustic signal.

6. The dual-mode positioning method for acoustic beacons and surface radio communication of a marine electronic anchor according to claim 5, characterized in that, The step of calculating the geographical location of the underwater acoustic beacon based on the location information includes: After determining the geographical coordinates of the surface radio module based on the location information, the relative position vector of the underwater acoustic beacon relative to the surface radio module is calculated based on the corrected target positioning acoustic signal. The relative position vector and the geographic coordinates are combined to obtain the geographic location of the underwater radio module.

7. The dual-mode positioning method for acoustic beacons and surface radio communication of a marine electronic anchor according to claim 6, characterized in that, The step of verifying the credibility of the corrected target positioning acoustic signal and the geographical location based on the state information includes: Based on the battery voltage and internal temperature parameters in the status information, the operating status level of the underwater radio module is determined. Based on the working level, the transmission stability of the corrected target positioning acoustic signal is determined, and based on the transmission stability, the reliability level of the geographical location is determined, and the verification result including the transmission stability and the reliability level is output.

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