High-precision marine observation beacon based on double-inertia motion sensor calibration

Abstract

The application discloses a high-precision marine observation beacon based on double-inertia motion sensor calibration. The system comprises a measurement subsystem responsible for initial data acquisition, a data processing and communication subsystem for post-processing analysis and real-time transmission of processed data, and a supporting subsystem. The measurement subsystem comprises a beacon body, inertia motion sensors and positioning equipment arranged in an array about the center of gravity, a tidal current measurement module, a meteorological measurement module, and a wave measurement module. During the measurement process, the six-degree-of-freedom motion response of the buoy is analyzed through the measurement results of the two sets of inertia motion sensors, and the motion characteristics of the devices carrying the sensors are calibrated to correct the collected data with high precision, thereby realizing high-precision observation of hydrodynamic conditions such as near-shore tidal current and wave. The data processing and communication subsystem analyzes the motion state of the beacon, calculates the motion state characteristics of other measurement devices carried thereon, and corrects the results, and finally analyzes and transmits the measured hydrodynamic elements in the region.

Description

Technical Field

[0001] This invention belongs to the field of nearshore surveying, specifically relating to a high-precision marine observation beacon calibrated based on dual inertial motion sensors. Background Technology

[0002] Coastal ports and nearshore engineering are important supports for economic development. Tide levels and wave conditions are crucial basic data for port and nearshore engineering. However, due to the fixed locations, high prices, inconvenience of use, and difficulty in providing real-time data of existing hydrodynamic measurement methods, real-time observation data is rarely obtained in engineering applications. This restricts the development of smart ports, coastal engineering safety early warning, disaster forecasting, and emergency decision-making, and also seriously affects the safety of coastal economic property and port terminal operations.

[0003] Traditional wave measurement methods include the following types: large-scale long-term wave stations use navigation marks or bottom-mounted self-recording long-term wave observation equipment, powered by shore for continuous long-term observation and data transmission. However, these instruments are expensive, installation conditions are limited, and they can only meet the needs of locations not far from the shore. Large-scale offshore navigation mark stations can be self-powered and can perform multi-element observations, but they are also expensive and pose certain risks to navigation when used near ports. Nearshore short-term wave observation instruments, such as "Wave Dragon," "Wave Knight," and "ADCP," can be used for nearshore engineering surveys. However, these devices generally cannot transmit data in real time and rely on manual timed data extraction. Furthermore, since their measurement principle generally uses ultrasonic measurement, a signal transmitter is required, resulting in relatively high energy consumption. Therefore, the observation time step and the amount of observation data are easily limited by battery capacity. In addition, the cost of using this type of equipment is high, thus placing a significant cost burden on wave observation in routine projects. Summary of the Invention

[0004] This invention addresses the technical bottlenecks of existing nearshore tidal and wave dynamics observation systems, such as low measurement accuracy, poor real-time performance, and high maintenance costs, by providing a high-precision marine observation beacon based on calibration using dual inertial motion sensors.

[0005] The present invention provides a high-precision marine observation beacon based on dual inertial motion sensor calibration, comprising a measurement subsystem, a data processing and communication subsystem, and an auxiliary power supply system;

[0006] The measurement subsystem includes the buoy body and two sets of inertial motion sensors, positioning equipment, tidal current measurement module, meteorological measurement module and wave measurement module mounted on the buoy body. The two sets of inertial motion sensors are identical and are arranged symmetrically about the center of gravity of the buoy.

[0007] The data processing and communication subsystem includes a beacon motion solver, an ocean dynamic element analyzer, and a communication module. The beacon motion solver, working in conjunction with two sets of inertial motion sensors and a positioning device, performs real-time analysis of the six-degree-of-freedom motion state of the beacon and corrects and compensates the inertial motion sensors. The ocean dynamic element analyzer uses the six-degree-of-freedom motion state characteristics of the beacon to correct the raw data from the tidal current measurement module, meteorological measurement module, and wave measurement module, thereby obtaining corrected high-precision tidal current, wave, and meteorological observation data. The communication module is used to upload the high-precision tidal current, wave, and meteorological observation data to a ground base station in real time.

[0008] The auxiliary power supply system is used to provide the electrical energy required for navigational beacon operations.

[0009] The system largely adopts the existing navigation beacon structure. It comprises three main subsystems: a measurement subsystem, a data processing and communication subsystem, and an auxiliary power supply subsystem. These subsystems are symmetrically arranged above and below the beacon's center of gravity using two sets of high-precision inertial motion and acceleration sensors. These sensors are combined with various other measurement sensors, including tidal current measurement, meteorological measurement, and wave measurement modules. The data processing and communication subsystem, working in conjunction with the dual inertial motion sensors and positioning equipment, enables real-time analysis of the beacon's six-degree-of-freedom motion state. It automatically corrects and compensates for the inertial motion sensors and uses the beacon's own motion characteristics to correct the raw data from the current velocity sensor and wave altimeter, thereby obtaining high-precision tidal current, wave, and meteorological observation data. Based on the aforementioned corrected multi-source measurement information, the data processing and communication subsystem uses a beacon motion solver and a marine dynamic element analyzer to fuse and analyze displacement, tilt angle, acceleration, and raw hydrodynamic signals. It extracts continuous surface wave curves and current velocity and direction distributions, and removes random noise using phase averaging and spatiotemporal filtering algorithms. This achieves high-precision time-series measurements of wave height at the centimeter level, period at the 0.1s level, wave direction and current direction at the 1° level, and current velocity at the 0.01m / s level. Simultaneously, the data processing and communication subsystem uploads the results in real-time to the backend platform (ground base station) via 5G or submarine fiber optic cables, providing reliable data support for intelligent marine early warning and numerical simulation. The auxiliary power supply system utilizes a combination of solar panels and high-capacity batteries, along with an efficient power management unit, ensuring that frequent battery replacements or manual maintenance are unnecessary after initial deployment.

[0010] This invention employs differential calculations using two sets of inertial motion sensors to eliminate inertial motion sensor correction errors online, ensuring long-term stability of observation accuracy. It utilizes the six-degree-of-freedom motion characteristics of the navigation beacon itself to actively correct current velocity and wave height measurement errors, achieving real-time online calibration of all elements. The invention has a compact structure, can directly upgrade existing navigation beacon infrastructure, and boasts low deployment costs and simple maintenance. It can sustainably provide high-resolution, low-latency nearshore hydrodynamic data, offering a reliable, economical, and efficient technical solution for applications such as coastal engineering safety early warning, tidal energy development, and marine environmental monitoring. Compared to existing observation methods that rely solely on a single sensor or floating platform, this invention has significant technical advantages in multi-sensor fusion, self-calibration, and real-time data transmission. Attached Figure Description

[0011] Figure 1 This is a system schematic diagram of the present invention;

[0012] Figure 2 This is a structural design diagram of the ground base station and navigation beacon system of the present invention;

[0013] Figure 3 This is a schematic diagram of the structure of the high-precision marine observation beacon of the present invention.

[0014] The components are shown in the attached diagram. Detailed Implementation

[0015] To further understand the invention's content, features, and effects, the following embodiments are provided, along with detailed descriptions in conjunction with the accompanying drawings:

[0016] like Figure 3 The diagram shows the structure of a high-precision marine observation beacon provided in an embodiment of the present invention. This high-precision marine observation beacon includes a measurement subsystem, a data processing and communication subsystem, and an auxiliary power supply system. The measurement subsystem is responsible for initial data acquisition and includes the beacon itself and two sets of inertial motion sensors, a positioning device, a tidal current measurement module, a meteorological measurement module, and a wave measurement module mounted on the beacon itself. The data processing and communication subsystem performs post-processing analysis and real-time transmission of the processed data and includes a beacon motion solver, a marine dynamic element analyzer, and a communication module. The auxiliary power supply system provides the electrical energy required for the beacon's operation and includes solar panels and batteries.

[0017] In this embodiment, the wave measurement module includes a capacitive wave height meter array installed around the buoy; the tidal current measurement module includes a current velocity sensor, which is a Doppler current profiler; the meteorological measurement module includes an anemometer, which is installed on top of the buoy. The capacitive wave height meter array, the Doppler current profiler, and the anemometer are all commonly used measurement sensors or devices in the art, and their working principles and installation requirements are well known in the art; therefore, this invention will not elaborate on them.

[0018] Each sensor is fixed at different heights on the top and lower central pipeline of the navigation beacon using corrosion-resistant stainless steel brackets or high-strength composite material supports. Dual inertial measurement units are positioned symmetrically above and below the beacon's center of gravity to ensure that the lengths of the lines connecting the two sets of sensors to the center of gravity are equal. A flow velocity sensor is fixed to the outside of the lower pipe gallery of the navigation beacon and can be rotated to keep its measurement port aligned with the main flow direction. Meteorological component detectors, such as anemometers and wind vanes, are installed at the top. All sensors are introduced into the central pipeline via sealed cables, converging on a data processing and communication subsystem mounted in the middle of the pipeline. This subsystem incorporates a multi-channel analog-to-digital converter and an anti-interference filter, and includes a reserved interface for a miniature thermal printhead for on-site calibration and verification.

[0019] like Figure 3 As shown, the measurement subsystem contains two identical sets of inertial motion sensors, arranged symmetrically about the center of gravity of the beacon. The position vectors of the two inertial motion sensors relative to the center of mass G are r1 and r2. Each inertial motion sensor includes a triaxial accelerometer and a gyroscope. The triaxial accelerometers of the two inertial motion sensors measure accelerations a1 and a2, respectively, and the gyroscopes measure angular velocities ω1 and ω2, respectively. At the sensor measurement points:

[0020] a1=a G +α×r1+ω×(ω×r1)

[0021] a2=a G +α×r²+ω×(ω×r²)

[0022] In the formula, a G Let α be the acceleration of the center of mass, ω be the angular acceleration, and ω be the angular velocity. Assuming the beacon is a rigid body, then ω1 = ω2 = ω.

[0023] refer to Figure 1 and Figure 2The data processing and communication subsystem includes a navigation beacon motion solver, an ocean dynamic element analyzer, and a communication module. The navigation beacon motion solver, in conjunction with two sets of inertial motion sensors and a positioning device, performs real-time analysis of the six-degree-of-freedom motion state of the navigation beacon and corrects and compensates the inertial motion sensors. The ocean dynamic element analyzer uses the six-degree-of-freedom motion state characteristics of the navigation beacon to correct the raw data from the tidal current measurement module, meteorological measurement module, and wave measurement module, thereby obtaining corrected high-precision tidal current, wave, and meteorological observation data. The communication module is used to upload the high-precision tidal current, wave, and meteorological observation data to the ground base station in real time.

[0024] It should be noted that after the sensors of the measurement subsystem acquire multi-source raw data and send it to the data processing and communication subsystem, the data processing and communication subsystem performs real-time preprocessing on the analog signals of various types of sensors. After filtering to remove high-frequency and DC drift interference, the analog signals are synchronously sampled by a multi-channel ADC to obtain digital waveforms.

[0025] The beacon motion solver adds and subtracts the measurement results from the two inertial motion sensors to obtain:

[0026] a1 + a2 = 2a G +ω×(ω×r1)+ω×(ω×r2)

[0027] a1-a2=α×(r1-r2)+ω×(ω×(r i -r2))

[0028] Since the two sets of inertial motion sensors are symmetrically positioned, let Δr = r1 - r2, and the above equation can be rewritten as:

[0029]

[0030] The acceleration a of the center of mass of the beacon is obtained. G The motion state of the buoy and the motion parameters of other sensors at any fixed position on the buoy are obtained by integrating the angular acceleration α and then integrating the angular acceleration α. ​​The motion of the other sensors is then corrected.

[0031] The beacon motion solver further corrects and compensates for the inertial motion sensor:

[0032] The zero drift and noise of the acceleration measured by the two inertial motion sensors are denoted as b, respectively. a,i and n a,i The zero drift of angular velocity and noise are denoted as b, respectively. g,i and n g,i Where the subscript i represents the serial number of the inertial motion sensor, and the relative deviation Δω(k) is calculated for each sample k:

[0033] Δω(k)=ω1(k)-ω2(k)=Δb g +Δn g

[0034] In the formula, Δb g =b g,1 -b g,2 ,Δn g =n g,1 -n g,2 Estimation using a sliding window or multi-sample averaging:

[0035]

[0036] Where N is the number of samples. For angular velocity, there is relative zero drift; similarly, for acceleration:

[0037]

[0038] In the formula, Δa(k)=Δb a +Δn a , Δb a =b a,1 -b a,2 ,Δn a =n a,1 -n a,2 ; This is to determine the relative zero drift of acceleration; thus, mutual correction is performed between the two inertial sensors:

[0039] and These are the corrected acceleration and angular velocity.

[0040] The marine dynamic element analyzer in this invention calls upon the six-DOF motion state time series of the navigation beacon, mapping the displacement and tilt changes of the tidal current measurement module, meteorological measurement module, and wave measurement module relative to the center of gravity back to the original measurement points. The observed values ​​are corrected using a rotation matrix and displacement vector, thereby eliminating measurement errors introduced by the navigation beacon's motion. For navigation beacons using Doppler current profilers, the corrected tidal current data is combined with the displacement information output by the positioning equipment (GNSS / RTK), and a spatiotemporally coherent flow field distribution is generated using a three-dimensional interpolation algorithm. After phase averaging, a steady-state tidal current profile is extracted.

[0041] This invention measures the motion state of a navigation beacon, including displacement, tilt angle, and acceleration signals, and analyzes the motion response relationship of the beacon under different wave processes. It then analyzes the wave process of the measured water surface and, combined with water level and flow velocity (direction) sensors, obtains the hydrodynamic elements of the measured area. The wave height measurement accuracy can reach the centimeter level, the period measurement accuracy can reach 0.1s, the wave direction and flow direction measurement accuracy can reach 1°, and the flow velocity measurement accuracy can reach 0.01m / s.

[0042] The power supply system uses a parallel connection of solar panels and lithium battery packs. The batteries and power management module are installed together in a waterproof compartment at the bottom of the pipeline. The module can intelligently switch charging and discharging modes according to sunlight and load conditions, and provides real-time feedback on voltage, current, and temperature status through a built-in monitoring chip. To ensure long-term unattended operation, the entire installation structure also includes protective devices such as anti-corrosion coatings and vibration damping pads to reduce environmental erosion.

[0043] After equipment installation, the buoy is slowly lowered using a marine crane, and the lead anchor is secured to the ground. During the on-site commissioning phase, the data processing and communication subsystem is accessed via radio or satellite link for clock synchronization, sampling frequency setting, and initial calibration corrections until the output of each channel is stable and the buoy's attitude parameters are within tolerance. Afterward, the buoy system can enter continuous observation mode, providing a reliable raw data source for subsequent data processing and transmission.

[0044] The marine dynamics analyzer starts with corrected wave height and pressure data. First, it extracts the dominant frequency band signal through time-domain detrending and second-order Butterworth bandpass filtering. Then, it performs Fast Fourier Transform (FFT) segmentation using a Hanning window to obtain the energy spectrum and wave energy distribution. It calculates key indicators such as significant wave height and average period using spectral methods, and performs wave direction spectrum inversion based on a multi-channel wave sensor array to obtain the direction and energy characteristics of wind waves, swells, and mixed wave fields. The obtained hydrodynamic elements and meteorological data are further integrated in the spatiotemporal domain: time-series cross-correlation analysis is used to dissect the wind-wave-current coupling mechanism, and an adaptive filter is used to remove occasional interference, achieving data consistency and integrity verification.

[0045] The processed results are packaged according to time scale, geographic coordinates, and data type, and transmitted to the shore server in frames via 5G or satellite links after data compression and encryption. Upon receiving the data, the backend platform performs secondary quality control, including signal anomaly detection, data missing interpolation, and redundancy verification, and stores the data in both time-series and relational database formats. The backend platform can also generate hydrodynamic element curves, flow field vector maps, and spectrum diagrams in real time based on user needs using its visualization module, and provides API interfaces for numerical models or early warning systems to use. Furthermore, the backend platform can periodically perform statistical analysis and trend prediction on historical datasets, providing long-term decision support for marine engineering design and marine environmental management.

[0046] Although preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other modifications under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these modifications are within the protection scope of the present invention.

Claims

1. A high-precision marine observation beacon calibrated based on dual inertial motion sensors, characterized in that, It includes a measurement subsystem, a data processing and communication subsystem, and an auxiliary power supply system; The measurement subsystem includes the buoy body and two sets of inertial motion sensors, positioning equipment, tidal current measurement module, meteorological measurement module and wave measurement module mounted on the buoy body. The two sets of inertial motion sensors are identical and are arranged symmetrically about the center of gravity of the buoy. The position vectors of the two inertial motion sensors relative to the center of mass G are r1 and r2. Each inertial motion sensor includes a triaxial accelerometer and a gyroscope. The triaxial accelerometers of the two inertial motion sensors measure accelerations a1 and a2, respectively, and the gyroscopes measure angular velocities. and At the sensor measurement point: ； ； In the formula, For the acceleration of the center of mass, Angular acceleration, Let ω be the angular velocity, and assume the beacon is a rigid body. Adding and subtracting the two equations, we get: ； ； Because the two sets of inertial motion sensors are symmetrically positioned, record Rewrite the above formula as: ； ； Obtain the acceleration of the center of mass of the navigation beacon and angular acceleration Then, the six-degree-of-freedom motion state of the navigation beacon and the motion parameters of other sensors at any fixed position on the navigation beacon are solved by integration, and the motion correction of other sensors is performed; The data processing and communication subsystem includes a beacon motion solver, an ocean dynamic element analyzer, and a communication module. The beacon motion solver, working in conjunction with two sets of inertial motion sensors and a positioning device, performs real-time analysis of the six-degree-of-freedom motion state of the beacon and corrects and compensates the inertial motion sensors. The ocean dynamic element analyzer uses the six-degree-of-freedom motion state characteristics of the beacon to correct the raw data from the tidal current measurement module, meteorological measurement module, and wave measurement module, thereby obtaining corrected high-precision tidal current, wave, and meteorological observation data. The communication module is used to upload the high-precision tidal current, wave, and meteorological observation data to a ground base station in real time. The correction of the inertial motion sensor includes: The zero drift and noise of the acceleration measured by the two inertial motion sensors are denoted as b, respectively. a,i and n a,i The zero drift of angular velocity and noise are denoted as b, respectively. g,i and n g,i Where the subscript i represents the serial number of the inertial motion sensor, and the relative deviation is calculated for each sample k. : ； In the formula, , Estimation using a sliding window or multi-sample averaging: ； Where N is the number of samples. For angular velocity, there is relative zero drift; similarly, for acceleration: ； In the formula, , , ; This is to determine the relative zero drift of acceleration; thus, mutual correction is performed between the two inertial sensors: ； ； and These are the corrected acceleration and angular velocity; The auxiliary power supply system is used to provide the electrical energy required for navigational beacon operations.

2. The high-precision marine observation beacon calibrated based on dual inertial motion sensors according to claim 1, characterized in that, The positioning device is GPS, which is used to obtain the location of navigational aids.

3. The high-precision marine observation beacon calibrated based on dual inertial motion sensors according to claim 1, characterized in that, The wave measurement module includes an array of capacitive wave height meters installed around the buoy; the tidal current measurement module includes a current velocity sensor, which is a Doppler current profiler; the meteorological measurement module includes a wind speed and direction meter, which is installed on top of the buoy.

4. The high-precision marine observation beacon calibrated based on dual inertial motion sensors according to claim 1, characterized in that, After the sensors of the measurement subsystem acquire multi-source raw data, the data processing and communication subsystem performs real-time preprocessing on the analog signals of various types of sensors. After filtering to remove high-frequency and DC drift interference, the analog signals are synchronously sampled by a multi-channel ADC to obtain digital waveforms.

5. The high-precision marine observation beacon calibrated based on dual inertial motion sensors according to claim 1, characterized in that, The marine dynamics analyzer calls the time series of the six-degree-of-freedom motion attitude of the navigation beacon, maps the displacement and tilt changes of the tidal current measurement module, meteorological measurement module, and wave measurement module relative to the center of gravity back to the original measurement point, and corrects the observation values ​​through rotation matrix and displacement vector to obtain corrected current velocity, wave and meteorological data, thereby eliminating the measurement error introduced by the motion of the navigation beacon.

6. The high-precision marine observation beacon calibrated based on dual inertial motion sensors according to claim 5, characterized in that, For navigation marks using Doppler current profilers, the corrected tidal flow data is combined with the displacement information output by the positioning device, and a spatiotemporally coherent flow field distribution is generated using a three-dimensional interpolation algorithm; after phase averaging, the steady-state tidal flow profile is extracted.

7. The high-precision marine observation beacon calibrated based on dual inertial motion sensors according to claim 4, characterized in that, The marine dynamic element analyzer starts from the corrected wave and meteorological data, extracts the main frequency band signal through time-domain detrending and second-order Butterworth bandpass filtering, and then performs fast Fourier transform segmented by Hanning window to obtain the energy spectrum and wave energy distribution; it calculates significant wave height and average period using the spectral method, and performs wave direction spectrum inversion based on the capacitive wave height meter array in the wave measurement module, thereby obtaining the direction and energy characteristics of wind waves, swells and mixed wave fields; The obtained hydrodynamic elements and meteorological data are further integrated in the spatiotemporal domain, and occasional interference is removed by an adaptive filter to achieve data consistency and integrity verification.

8. The high-precision marine observation beacon calibrated based on dual inertial motion sensors according to claim 1, characterized in that, The auxiliary power supply system includes solar panels and batteries; the communication module transmits high-precision tidal current, wave and meteorological observation data to the ground base station via 5G or satellite link in frames.

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