Monitoring Method and System for Offshore Oil Platforms Based on Beidou High-Precision Positioning Technology

Abstract

The present invention discloses a monitoring method for an offshore oil platform based on Beidou high-precision positioning technology, which relates to the field of ocean engineering. The method includes arranging a Beidou enhanced anti-interference receiving unit to collect Beidou B1C signal data of the column; performing differential solution on the B1C signal data, and cooperating with a circular antenna array to suppress sea surface scattering interference, and outputting the spatial coordinate values of three measuring points of the column; based on the spatial coordinate values of the three measuring points of the column, using piecewise curve fitting to calculate the bending deformation curve of the column, and extracting the maximum lateral displacement of the column; when the maximum lateral displacement of the column continuously exceeds a preset length within 10 minutes and the included angle between the displacement direction and the wind direction is less than a first preset angle, generating an alarm message for excessive deformation of the column. The present invention can effectively solve the problems of large signal interference, insufficient positioning accuracy and difficulty in realizing real-time global deformation monitoring in the prior art in a complex marine environment, thereby significantly improving the reliability and accuracy of the structural safety monitoring of offshore oil platforms.

Description

Technical Field

[0001] The present invention relates to the field of ocean engineering, and particularly to a monitoring method and system for offshore oil platforms based on Beidou high-precision positioning technology. Background Art

[0002] With the continuous deepening of ocean resource development, offshore oil platforms, as the core facilities for offshore oil and gas resource exploration and exploitation, play an important role in the field of ocean engineering in terms of their stability and safety. The structure of an offshore oil platform usually needs to withstand complex environmental conditions, including various external forces such as sea waves, wind loads, tides, and geological movements. This makes the monitoring and maintenance of the platform structure one of the key technical fields to ensure the safe operation of the oil platform. In recent years, with the development of high-precision positioning technology, especially the wide application of the Beidou satellite navigation system, it provides technical support with high precision, real-time performance, and strong anti-interference ability for the structural monitoring of offshore oil platforms. The Beidou high-precision positioning technology uses high-precision satellite-based differential and network RTK (Real-Time Kinematic) and has been widely used in centimeter-level or even higher-precision spatial positioning. At the same time, by combining means such as antenna arrays and signal processing algorithms, it can effectively suppress multipath interference and positioning errors in complex environments, providing a technical basis for realizing platform structural deformation monitoring.

[0003] However, there are still many deficiencies in the current structural monitoring technologies for offshore oil platforms. Traditional monitoring methods mostly rely on manual periodic inspections or the installation of fixed sensors to obtain physical parameters such as the deformation and inclination of the platform structure. These methods are limited by the complexity of instrument layout, insufficient real-time performance of monitoring data, and the influence of environmental interference, and cannot provide reliable monitoring results in harsh ocean environments. At the same time, the existing monitoring schemes based on satellite navigation systems also face challenges in practical applications. Offshore oil platforms are usually located in far-sea areas, and satellite signals are affected by factors such as multi-path reflection on the sea surface and wireless signal interference, making it difficult to achieve high-precision positioning. In addition, traditional positioning monitoring schemes usually focus on a single measurement point or multiple independent measurement points, lacking a global analysis of the overall structural deformation of the platform, and it is difficult to timely and accurately evaluate the stress state and safety condition of the platform in complex environments. Therefore, there is an urgent need for an innovative monitoring method that can combine high-precision positioning technology and intelligent algorithms to adapt to the complex and changeable operating environment of offshore oil platforms. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention is proposed.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a monitoring method for an offshore oil platform based on Beidou high-precision positioning technology, which includes,

[0007] Beidou enhanced anti-interference receiving units are respectively arranged at the bottom, middle and top of the columns of the offshore oil platform to collect Beidou B1C signal data of the columns;

[0008] The multi-base station network RTK technology is used to perform differential resolution on the B1C signal data, and the loop antenna array is used to suppress the sea surface scattering interference, and the spatial coordinate values of the three measurement points of the column are output;

[0009] Based on the spatial coordinate values of the three measurement points of the column, a segmented curve fitting is used to calculate the bending deformation curve of the column, and the maximum lateral displacement of the column is extracted;

[0010] When the maximum lateral displacement of the column continuously exceeds a preset length within 10 minutes and the included angle between the displacement direction and the wind direction is less than the first preset angle, an alarm message for excessive deformation of the column is generated.

[0011] As a preferred scheme of the method for monitoring an offshore oil platform based on Beidou high-precision positioning technology of the present invention, wherein: the differential resolution includes cycle slip detection, ambiguity fixing and tropospheric delay correction;

[0012] The cycle slip detection includes:

[0013] When the B1C signal data enters the cycle slip detection module, a Doppler frequency shift prediction value is constructed;

[0014] The Doppler frequency shift prediction value is compared with the measured carrier phase observation value of the current epoch. If the difference between the two exceeds a preset threshold, it is marked as a suspected cycle slip point; for the suspected cycle slip point, the ionospheric residual third-order difference method is used for secondary inspection;

[0015] If a cycle slip point is found, the repair module is called to repair the cycle slip. After the cycle slip repair is completed, the residual inspection is performed on the repair result, and the cycle slip detection is completed by using multiple consecutive carrier phase observation values in each sampling interval.

[0016] As a preferred scheme of the method for monitoring an offshore oil platform based on Beidou high-precision positioning technology of the present invention, wherein: after the cycle slip detection is completed, the ambiguity fixing is performed on the processed carrier phase observation value, including:

[0017] A double-difference observation equation of the Beidou B1C signal is established, and the reference station with the best signal quality is selected as the main reference station;

[0018] When the satellite elevation angle is lower than the second preset angle, the observation value of this satellite is excluded from the double-difference observation equation;

[0019] Tropospheric delay correction is performed on the double-difference observation equation;

[0020] The sequential least squares method is used to construct a floating-point solution estimation model. When the variance-covariance factor of the floating-point solution estimation is less than the first preset value and the redundancy of the observation equation is greater than the second preset value, the ambiguity search is started to obtain a candidate integer solution set;

[0021] The ratio test method is used to evaluate the reliability of the candidate integer solution set, and this set of ambiguity fixing results is accepted through judgment.

[0022] As a preferred solution of the offshore oil platform monitoring method based on the Beidou high-precision positioning technology of the present invention, wherein: extracting the maximum lateral displacement of the column includes:

[0023] Converting the obtained spatial coordinate values to the local coordinate system of the column;

[0024] Checking the converted coordinate values. When the coordinate value of a certain measuring point deviates abnormally, re-RTK calculation is performed on this measuring point;

[0025] Perform two-dimensional curve fitting in the XOZ plane and the YOZ plane respectively to establish a piecewise cubic polynomial equation system;

[0026] Solve the established piecewise cubic polynomial equation system by the chasing method, obtain the polynomial coefficients of each section of the curve and calculate the fitting residuals at the measuring points. If the fitting residuals do not meet the conditions, adjust the node positions or increase the number of nodes and then refit;

[0027] Based on the polynomial coefficients, determine the maximum value of the combined displacement, which is the maximum lateral displacement of the column.

[0028] As a preferred solution of the offshore oil platform monitoring method based on the Beidou high-precision positioning technology of the present invention, wherein: the logic of obtaining the polynomial coefficients of each section of the curve is as follows:

[0029] Convert the linear equation system into a tridiagonal matrix equation in the standard form of the chasing method, and use the chasing method to solve it to obtain the second derivative values at each node;

[0030] Calculate the four coefficients of each section of the curve from the second derivative values at each node;

[0031] Perform sampling verification on each section of the curve to check whether the continuity conditions at the nodes are met. If not, re-solve by the chasing method. If satisfied, output the polynomial coefficients of each section of the curve;

[0032] The solution using the chasing method includes forward elimination. Starting from the first equation, the lower diagonal elements are gradually eliminated while recording the elimination multipliers. After forward elimination is completed, back substitution is performed, starting from the last equation to solve each unknown in turn. If the solution of an unknown shows an outlier, the coefficients of the equation system are rechecked.

[0033] As a preferred embodiment of the offshore oil platform monitoring method based on Beidou high-precision positioning technology according to the present invention, the calculation of the fitting residual is shown as follows:

[0034] ;

[0035] where the weight function :

[0036] ;

[0037] where is the optimized fitting residual value, is the total number of measurement points, is the measured value of the i-th measurement point, is the spline function fitting value, is the weight function, is the distance from the i-th measurement point to the adjacent node, is the value of the elevation change influence coefficient, is the value of the distance attenuation coefficient, is the elevation difference between adjacent measurement points, is the horizontal distance between adjacent measurement points.

[0038] As a preferred embodiment of the offshore oil platform monitoring method based on Beidou high-precision positioning technology according to the present invention, the float solution estimation model can be expressed by the following formula:

[0039] ;

[0040] where the weight function :

[0041] ;

[0042] where the variance adjustment function :

[0043] ;

[0044] where is the float solution estimation value of the current epoch, is the number of effective satellites, is the observation value weight coefficient of the i-th satellite, is the elevation angle of the i-th satellite, is the signal-to-noise ratio of the i-th satellite, is the variance cofactor of the current epoch, is the observation value of the i-th satellite.

[0045] In a second aspect, an embodiment of the present invention provides an offshore oil platform monitoring system based on Beidou high-precision positioning technology, which includes:

[0046] An acquisition module, configured to respectively deploy Beidou enhanced anti-interference receiving units at the bottom, middle, and top of the columns of the offshore oil platform, and acquire Beidou B1C signal data of the columns;

[0047] A spatial coordinate calculation module, configured to perform differential solution on the B1C signal data by using multi-base station network RTK technology, cooperate with a circular antenna array to suppress sea surface scattering interference, and output the spatial coordinate values of three measurement points of the column;

[0048] A maximum transverse displacement extraction module, configured to calculate the bending deformation curve of the column by using piecewise curve fitting based on the spatial coordinate values of three measurement points of the column, and extract the maximum transverse displacement of the column;

[0049] An alarm module, configured to generate an alarm message for excessive deformation of the column when the maximum transverse displacement of the column continuously exceeds a preset length within 10 minutes and the included angle between the displacement direction and the wind direction is less than a first preset angle.

[0050] In a third aspect, an embodiment of the present invention provides a computer device, including a memory and a processor, where the memory stores a computer program, and: when the processor executes the computer program, any step of the above-mentioned offshore oil platform monitoring method based on Beidou high-precision positioning technology is implemented.

[0051] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, and: when the computer program is executed by a processor, any step of the above-mentioned offshore oil platform monitoring method based on Beidou high-precision positioning technology is implemented.

[0052] The beneficial effects of the present invention are as follows: By combining the Beidou high-precision positioning technology with the multi-base station network RTK technology, Beidou enhanced anti-interference receiving units are innovatively arranged at the bottom, middle, and top of the columns of the offshore oil platform to collect and process Beidou B1C signal data in real time, and the loop antenna array is used to effectively suppress the sea surface scattering interference to ensure the acquisition of high-precision spatial coordinates. Further, the bending deformation curve and the maximum lateral displacement of the column are accurately calculated by the piecewise curve fitting method, and combined with the wind direction data, a real-time warning of excessive deformation of the platform structure is realized. This solution has significant improvements in key technologies such as multipath interference suppression, cycle slip detection and repair, ambiguity fixing, and the accuracy and robustness of the fitting algorithm, and can effectively solve the problems of large signal interference, insufficient positioning accuracy, and difficulty in realizing real-time global deformation monitoring in the existing technology in complex marine environments, thus significantly improving the reliability and accuracy of the structural safety monitoring of offshore oil platforms and providing an important technical guarantee for the efficient operation and safety management of the platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings according to these drawings without creative efforts. Among them:

[0054] Figure 1 It is a flowchart of a monitoring method for an offshore oil platform based on Beidou high-precision positioning technology. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the drawings of the specification. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0056] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0057] Second, the so-called "one embodiment" or "embodiment" herein refers to specific features, structures or characteristics that may be included in at least one implementation manner of the present invention. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or alternative embodiments that are mutually exclusive of other embodiments.

[0058] The present invention will be described in detail with reference to schematic diagrams. When describing the embodiments of the present invention in detail, for the convenience of explanation, the cross-sectional views showing the device structure will be enlarged locally in a non-general proportion, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention herein. In addition, in actual production, three-dimensional spatial dimensions of length, width and depth should be included.

[0059] Meanwhile, in the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper, lower, inner and outer" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0060] Unless otherwise clearly defined and limited in the present invention, the terms "mounted, connected, connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, and can also be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0061] Embodiment 1:

[0062] Referring to Figure 1 , which is the first embodiment of the present invention. This embodiment provides a method for monitoring an offshore oil platform based on Beidou high-precision positioning technology, including:

[0063] S1. Respectively deploy Beidou enhanced anti-interference receiving units at the bottom, middle and top of the columns of the offshore oil platform, and collect the Beidou B1C signal data of the columns. The sampling frequency of the B1C signal data is 2 Hz;

[0064] At 1.5 meters above sea level at the bottom of each column of the offshore oil platform, 35 meters above sea level in the middle, and 70 meters above sea level at the top, BeiDou enhanced anti-interference receiving units are fixedly installed respectively. Among them, the anti-interference receiving unit adopts a built-in microstrip antenna array structure. The microstrip antenna array is composed of 8 ceramic substrate antenna oscillators evenly distributed in a ring. The center frequency of the ceramic substrate antenna oscillator is 1575.42 MHz, and the bandwidth is 40 MHz. The shell of the anti-interference receiving unit is made of 316L stainless steel, and the surface is treated with a Teflon coating, with an IP67 protection level, and can work stably in the temperature range of -40°C to 85°C. The anti-interference receiving unit internally integrates a 72-channel RF front-end circuit. The RF front-end circuit includes a low-noise amplifier, a band-pass filter, and an analog-to-digital converter. Among them, the noise figure of the low-noise amplifier is less than 1.5 dB, and the gain is 35 dB. The anti-interference receiving unit is connected to the signal processing host through a military-grade waterproof aviation plug. The aviation plug adopts a full-metal sealed structure, and the sealing ring is made of fluororubber. The signal processing host uses a TMS320C6678 processor with a main frequency of 1.25 GHz, and internally integrates a self-developed space-time adaptive interference detection and suppression algorithm. The algorithm adopts the minimum variance distortionless response criterion. The anti-interference receiving unit collects BeiDou-3 B1C signal data. The B1C signal data includes a pilot component and a data component. Among them, the pilot component adopts the BOC(1,1) modulation method, and the code rate is 1.023 Mbps. The data component adopts the QPSK modulation method, and the code rate is 1.023 Mbps. The sampling frequency of the B1C signal data is set to 2 Hz, that is, a complete phase observation value and pseudorange observation value are collected every 0.5 seconds. Among them, the accuracy of the phase observation value is better than 0.1 cycle, and the accuracy of the pseudorange observation value is better than 0.1 meter.

[0065] S2. Use the multi-base station network RTK technology to perform differential resolution on the B1C signal data, and cooperate with the circular antenna array to suppress the sea surface scattering interference, and output the spatial coordinate values of the three measuring points of the column.

[0066] Use the multi-base station network RTK technology composed of 6 reference stations to perform differential resolution on the B1C signal data. Among them, the reference stations are distributed in a regular hexagon centered on the platform to be monitored. The distance between adjacent reference stations is 15 kilometers. Each reference station is equipped with a BeiDou-3 full-frequency receiver and a cesium atomic clock. The frequency stability of the cesium atomic clock is better than 5×10^-13. The reference stations are interconnected through submarine optical cables. The optical cable adopts a steel wire armored and strengthened structure, and the transmission delay is less than 0.5 milliseconds.

[0067] The differential resolution process is divided into three sequentially executed stages:

[0068] In the first stage, cycle slip detection is performed. When the B1C signal data enters the cycle slip detection module, first, a predicted Doppler frequency shift value is constructed, which is calculated based on the carrier phase observations of the previous three epochs. Then, the predicted Doppler frequency shift value is compared with the measured carrier phase observation of the current epoch. If the difference between the two exceeds 0.5 cycles, it is marked as a suspected cycle slip point. For the suspected cycle slip point, the ionospheric residual third-order difference method is used for secondary verification. The ionospheric residual third-order difference method combines the carrier phase observations and pseudorange observations of four consecutive epochs to form ionospheric combined observables. When the epoch-to-epoch difference of the ionospheric combined observables exceeds the threshold of 0.3 cycles, it is confirmed as a cycle slip point. If a cycle slip point is detected, the adaptive Kalman filter repair module is called. The adaptive Kalman filter repair module calculates the size of the cycle slip based on the carrier phase observations of the previous and current epochs. After the cycle slip is repaired, a residual test is performed on the repair result. The residual test uses the Chi-square test method. When the residual exceeds the 95% confidence interval, the repair result is marked as invalid, and the data of this epoch is excluded in subsequent calculations. The sampling interval for cycle slip detection is 0.5 seconds, corresponding to a data sampling frequency of 2 Hz. At least 4 consecutive carrier phase observations are required in each sampling interval to complete cycle slip detection. The data output by the cycle slip detection module includes three parameters: cycle slip flag, repair flag, and quality index. The quality index reflects the reliability of cycle slip detection, and its value range is 0 - 100.

[0069] In the second stage, ambiguity fixing is performed. After cycle slip detection and repair are completed, ambiguity fixing is performed on the processed carrier phase observations. First, a double-difference observation equation for the Beidou B1C signal is established, and the reference station with the best signal quality is selected as the main reference station. When the satellite elevation angle is lower than 15 degrees, the observations of this satellite are automatically excluded from the double-difference observation equation.

[0070] Then, the Saastamoinen model is used to correct the tropospheric delay for the double-difference observation equation. Next, the sequential least squares method is used to construct a floating-point solution estimation model. The weight coefficient of the observed value in the floating-point solution estimation model is calculated based on the satellite elevation angle and signal-to-noise ratio. When the variance-covariance factor of the floating-point solution estimation is less than 0.003 and the redundancy of the observation equation is greater than 4, the ambiguity search is started. The ambiguity search first performs a Z-transform decoration on the floating-point solution covariance matrix, and the Lovász reduction algorithm is used to make the condition number of the decorated covariance matrix less than 100. Then, in the decorated search space, the shrinkage factor method is used to determine the candidate solution region. The shrinkage factor is adaptively adjusted according to the epoch-to-epoch correlation, and its value range is 0.5 - 0.9. When the candidate integer solution set is obtained, the ratio test method is used to evaluate the reliability of the ambiguity fixation. The ratio of the sum of the squared residuals of the optimal solution and the sub-optimal solution is calculated. If this ratio is greater than 3 and the posterior standard error of unit weight of the optimal solution is less than 0.8, then this set of ambiguity fixation results is accepted. For the ambiguities that are reliably fixed, the partial fixation strategy is adopted. When the standard deviation of a single ambiguity is greater than 0.15 cycles, it is maintained in the floating-point solution state. The time window for ambiguity fixation is 5 seconds. If a reliable fixed solution cannot be obtained within one time window, the floating-point solution state is maintained and data for the next time window is awaited. Finally, the ambiguity fixation results are output, including the fixed solution status flag, the ambiguity integer value, and the fixed reliability index.

[0071] The general expression of the floating-point solution estimation model can be represented by the following formula:

[0072] ;

[0073] Among them, the weight function:

[0074] ;

[0075] Among them, the variance adjustment function:

[0076] ;

[0077] Among them, is the floating-point solution estimated value of the current epoch, is the number of effective satellites, is the weight coefficient of the observation value of the i-th satellite, is the elevation angle (in radians) of the i-th satellite, is the signal-to-noise ratio (dB-Hz) of the i-th satellite, is the variance-covariance factor of the current epoch, is the observation value of the i-th satellite.

[0078] It should be noted that although the above description outlines the general process of ambiguity fixation, various complex situations may be encountered in practical engineering applications that require special handling. For example, when the monitoring platform is located at sea, the sea surface multipath effect will significantly affect the quality of the observed values. In this case, a multipath correction term needs to be introduced into the double-difference observation equation. Specifically, if the observed value of a certain satellite is significantly affected by the multipath effect (usually manifested as a rapid fluctuation in the signal-to-noise ratio), the system will automatically reduce the weight of this observed value and even exclude it if necessary.

[0079] During the floating-point solution estimation stage, the processing strategies under different environmental conditions will also vary. For example, during periods of intense ionospheric activity (such as during magnetic storms), the system will automatically shorten the time window length from the standard 5 seconds to 2 - 3 seconds to reduce the impact of ionospheric residuals. If a situation with poor satellite distribution geometry is encountered (such as a PDOP value greater than 6), the system will automatically extend the observation time until the geometric strength improves before calculating the fixed solution.

[0080] The specific implementation during the ambiguity search process also varies depending on the actual conditions. For example, in a situation with good signals (such as an open field), the system can obtain a reliable fixed solution within 1 - 2 epochs; while in a complex environment (such as with obstacles or electromagnetic interference), it may require data from multiple epochs to complete the ambiguity fixation.

[0081] In the third stage, calculate the spatial coordinate values. After obtaining the fixed solution, use the weighted least squares adjustment algorithm to calculate the spatial coordinate values of the three measuring points of the column.

[0082] More specifically, after obtaining a reliable ambiguity fixed solution, when using the weighted least squares adjustment algorithm to calculate the spatial coordinate values of the three measuring points of the column, first establish an observation error equation. The error equation includes the fixed carrier phase observation value and the pseudorange observation value. The weight coefficient of the carrier phase observation value is set to 1, and the weight coefficient of the pseudorange observation value is set to 0.01; when the residual of the observed value of a certain satellite exceeds 3 times the mean error, reduce the weight coefficient of this observed value to 50% of the original; then construct a coefficient matrix. The elements of the coefficient matrix are calculated from the satellite position and the approximate position of the receiver. The satellite position is calculated using precise ephemeris, and the time delay of the precise ephemeris does not exceed 30 seconds.

[0083] Then, an iterative method is adopted to solve the weighted least squares adjustment equation. The iteration stops when the difference between the solutions of two adjacent iterations is less than 1 mm or the number of iterations reaches 10 times. Variance component estimation is performed on the adjustment results, and the accuracy indexes of the positioning results are calculated, including the standard deviations in the eastward, northward, and elevation directions. When the horizontal standard deviation is greater than 2 cm or the elevation standard deviation is greater than 3 cm, the observed values are re-screened. After excluding the abnormal observed value with the largest contribution value, the adjustment calculation is carried out again. The adjustment calculation uses the 2000 National Geodetic Coordinate System. First, the coordinate values in the geodetic coordinate system are obtained, and then they are converted into three components: longitude, latitude, and geodetic height. Considering the fixed relative positions of the three measuring points on the column, distance constraints between the measuring points are introduced during the adjustment process. The weight coefficient of the distance constraint is set to 100, and an abnormal warning is issued when the change in the distance between points after adjustment exceeds 5 mm. Finally, the coordinate values of the measuring points and their accuracy indexes are output. The accuracy indexes include the standard deviations of the coordinate components and the parameters of the position error ellipse.

[0084] It should be noted that although the above description outlines the general process of differential solution using the multi-base station network RTK technology, the specific implementation details may vary according to different monitoring environments and hardware configurations. For example, in typhoon weather, strong winds may cause slight antenna vibrations. At this time, the system will automatically increase the sampling rate of the carrier phase observed values from the standard 2 Hz to 5 Hz or higher to better capture the slight movements of the platform. In case of heavy rainfall weather, the system will increase the weight of the tropospheric delay correction and may enable the multipath effect monitoring module to cope with the influence of raindrops on signal propagation. Particularly worth mentioning is the application of the circular antenna array, which greatly improves the anti-interference ability of the system. For example, when the sea surface is rough, the intensity and direction of the reflected signal will change violently. At this time, the antenna array can adjust the beam direction in real time to maintain effective suppression of the interference signal. In actual engineering, there are already cases showing that this technology can reduce the positioning error caused by sea surface reflection from the centimeter level to the millimeter level.

[0085] S3. Based on the spatial coordinate values of the three measuring points on the column, a segmented curve fitting is used to calculate the bending deformation curve of the column, and the maximum lateral displacement of the column is extracted.

[0086] The coordinate values of the three measuring points obtained by RTK solution are converted from the 2000 National Geodetic Coordinate System to the local coordinate system of the column. The local coordinate system takes the center of the bottom of the column as the origin, the vertical upward direction as the Z-axis, the direction pointing due east as the X-axis, and the direction pointing due north as the Y-axis.

[0087] Check the converted coordinate values. When the coordinate value of a certain measuring point deviates abnormally (the relative position change with the adjacent measuring point exceeds 5 mm), re-perform RTK calculation for this measuring point; check the distance between measuring points. When the distance between adjacent measuring points is greater than 10 m, add a node between the two measuring points according to the equal-distance principle.

[0088] Furthermore, perform two-dimensional curve fitting in the XOZ plane and the YOZ plane respectively, using piecewise cubic spline functions, with the requirements:

[0089] The function values of adjacent segments are continuous at the nodes;

[0090] The first-order derivatives of adjacent segments are continuous at the nodes;

[0091] The second-order derivatives of adjacent segments are continuous at the nodes;

[0092] The included angle between the tangent direction at the bottom of the column and the vertical direction is less than 0.1 degree;

[0093] Solve the established piecewise cubic polynomial equations by the chasing method to obtain the polynomial coefficients of each segment of the curve; calculate the fitting residuals at the measuring points. When the root mean square value of the residuals is greater than 3 mm, it is necessary to adjust the node positions or increase the number of nodes and then re-perform fitting.

[0094] Calculate the displacement values at intervals of 0.1 m on the fitted curve, and obtain respectively:

[0095] The maximum displacement in the X direction and its occurrence position;

[0096] The maximum displacement in the Y direction and its occurrence position;

[0097] Synthesize the displacement amounts in the X and Y directions to obtain the resultant displacement amount in the horizontal plane;

[0098] Determine the maximum value of the resultant displacement amount, which is the maximum lateral displacement amount of the column.

[0099] More specifically, the logic for obtaining the polynomial coefficients of each segment of the curve is as follows:

[0100] First, establish a cubic polynomial expression for each segment of the curve. Each segment of the curve contains four undetermined coefficients. Adjacent curve segments establish equations through the continuity conditions at the nodes; when there are n nodes, n - 1 segments of curves will be generated, and a total of 4(n - 1) coefficients need to be determined; then, according to the continuity conditions at the nodes, including continuous function values, continuous first-order derivatives, and continuous second-order derivatives, establish 3(n - 2) equations; apply fixed-end constraint conditions at the bottom of the column to provide 2 equations; apply free-end constraint conditions at the top to provide 2 equations; thus, a complete linear equation system is obtained.

[0101] Next, transform the system of linear equations into a tridiagonal matrix equation in the standard form of the chasing method, and then use the chasing method to solve it. First, perform forward elimination. Starting from the first equation, gradually eliminate the lower diagonal elements while recording the elimination multipliers. After the forward elimination is completed, perform back substitution. Starting from the last equation, solve each unknown in turn. If the solution of an unknown appears as an outlier (more than 100 times the expected range), then recheck the coefficients of the system of equations.

[0102] After obtaining the second derivative values at each node, substitute them into the piecewise cubic polynomial expression to calculate the four coefficients of each curve segment. Sample and verify each curve segment to check whether the continuity conditions at the nodes are satisfied. When the deviation of the continuity conditions exceeds 10^-6, the chasing method needs to be re-solved. Finally, output the polynomial coefficients of each curve segment. The deformation state of the column at any height can be completely expressed by the coefficients of the piecewise cubic polynomial, and the displacement value can be obtained through the polynomial coefficients.

[0103] For example, for the height Z, first determine the curve segment it is in. Assume it is in the i-th segment, and the polynomial coefficients of this segment are a i 、b i 、c i 、d i .

[0104] Substitute Z into the polynomial equation of this segment:

[0105] Displacement in the X direction = a i (Z - Z i )³ + b i (Z - Z i )² + c i (Z - Z i ) + d i ;

[0106] The displacement in the Y direction is calculated by the same method, only using the polynomial coefficients in the Y direction;

[0107] Starting from the bottom of the column (Z = 0), calculate the displacement values in the X and Y directions at a position every 0.1 meter:

[0108] Z = 0, 0.1, 0.2,..., H meters (H is the total height of the column);

[0109] A series of discrete displacement values can be obtained.

[0110] For each calculated position, synthesize the displacements in the X and Y directions:

[0111] Synthesized displacement = √(X displacement² + Y displacement²);

[0112] By comparing the composite displacements at all calculated positions, the maximum value and its corresponding height position are found. In this way, the complete deformation information of the column along the height direction can be accurately obtained.

[0113] It should be noted that the general formula for the fitting residuals at the calculated measurement points can be expressed by the following formula:

[0114] ;

[0115] Among them, the weight function:

[0116] ;

[0117] Among them, is the optimized fitting residual value, is the total number of measurement points, is the measured value of the i-th measurement point, is the spline function fitting value, is the weight function, is the distance from the i-th measurement point to the adjacent node, The elevation change influence coefficient takes a value of 0.1, The distance attenuation coefficient takes a value of 0.05, is the elevation difference between adjacent measurement points, is the horizontal distance between adjacent measurement points. The size of the residual directly reflects the degree of coincidence between the fitting curve and the measured points. By judging the fitting residual value, it can be determined whether the fitted curve meets the requirements and whether the maximum lateral displacement obtained is accurate. If the fitting residual value does not meet the requirements, the curve needs to be refitted.

[0118] When the maximum lateral displacement of the column continuously exceeds 15 cm within 10 minutes and the included angle between the displacement direction and the wind direction is less than 30 degrees, an alarm message for excessive deformation of the column is generated.

[0119] Furthermore, this embodiment also provides an offshore oil platform monitoring system based on Beidou high-precision positioning technology, including:

[0120] A collection module for respectively arranging Beidou enhanced anti-interference receiving units at the bottom, middle, and top of the columns of the offshore oil platform to collect Beidou B1C signal data of the columns;

[0121] A spatial coordinate calculation module for performing differential resolution on the B1C signal data by using multi-base station network RTK technology, suppressing sea surface scattering interference with a circular antenna array, and outputting the spatial coordinate values of the three measurement points of the column;

[0122] The maximum lateral displacement extraction module is used to calculate the bending deformation curve of the column by piecewise curve fitting based on the spatial coordinate values of the three measuring points of the column, and extract the maximum lateral displacement of the column.

[0123] The alarm module is used to generate an alarm message for excessive deformation of the column when the maximum lateral displacement of the column continuously exceeds a preset length within 10 minutes and the included angle between the displacement direction and the wind direction is less than the first preset angle.

[0124] This embodiment also provides a computer device, which is applicable to the situation of the monitoring method of an offshore oil platform based on Beidou high-precision positioning technology, including a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the monitoring method of the offshore oil platform based on Beidou high-precision positioning technology as proposed in the above embodiment.

[0125] This computer device can be a terminal, and this computer device includes a processor, a memory, a communication interface, a display screen, and an input device connected through a system bus. Among them, the processor of this computer device is used to provide computing and control capabilities. The memory of this computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of this computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a carrier network, NFC (Near Field Communication), or other technologies. The display screen of this computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of this computer device can be a touch layer covered on the display screen, or a button, a trackball, or a touchpad set on the housing of the computer device, or an external keyboard, touchpad, or mouse, etc.

[0126] This embodiment also provides a storage medium, on which a computer program is stored, and when this program is executed by a processor, it implements the monitoring method of an offshore oil platform based on Beidou high-precision positioning technology as proposed in the above embodiment.

[0127] The storage medium proposed in this embodiment and the data storage method proposed in the above embodiment belong to the same inventive concept. The technical details not described in detail in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0128] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A method for monitoring an offshore oil platform based on Beidou high-precision positioning technology, characterized in that: include, Beidou enhanced anti-interference receiving units are respectively arranged at the bottom, middle and top of the columns of the offshore oil platform to collect Beidou B1C signal data of the columns; The multi-base station network RTK technology is used to perform differential analysis on the B1C signal data, and the circular antenna array is used to suppress the interference of sea surface scattering, and the spatial coordinate values ​​of the three measuring points of the column are output; Based on the spatial coordinate values ​​of the three measuring points of the column, the bending deformation curve of the column is calculated by piecewise curve fitting to extract the maximum lateral displacement of the column; When the maximum lateral displacement of the column is continuously greater than the preset length within 10 minutes, and the angle between the displacement direction and the wind direction is less than the first preset angle, an alarm message of excessive deformation of the column is generated; Extracting the maximum lateral displacement of the column includes: The obtained spatial coordinate values ​​are converted to the local coordinate system of the column; Check the converted coordinate values. If the coordinate value of a certain measuring point deviates abnormally, re-RTK solve the measuring point. Two-dimensional curve fitting was performed in the XOZ plane and the YOZ plane respectively to establish a set of piecewise cubic polynomial equations; The established piecewise cubic polynomial equation group is solved by the chasing method to obtain the polynomial coefficients of each segment of the curve and calculate the fitting residual at the measuring point. If the fitting residual does not meet the conditions, the node position is adjusted or the number of nodes is increased and the fitting is performed again; The maximum value of the combined displacement is determined based on the polynomial coefficients, that is, the maximum lateral displacement of the column.

2. The offshore oil platform monitoring method based on Beidou high-precision positioning technology as claimed in claim 1, characterized in that: The differential analysis includes cycle slip detection, ambiguity fixation and tropospheric delay correction; The cycle slip detection comprises: When the B1C signal data enters the cycle slip detection module, a Doppler frequency shift prediction value is constructed; The Doppler frequency shift prediction value is compared with the actual carrier phase observation value of the current epoch. If the difference between the two exceeds a preset threshold, it is marked as a suspected cycle slip point. For the suspected cycle slip point, a secondary test is performed using the ionospheric residual third-order difference method; If a cycle slip point is found, the repair module is called to repair the cycle slip. After the cycle slip repair is completed, a residual check is performed on the repair result, and the cycle slip detection is completed using multiple continuous carrier phase observation values ​​in each sampling interval.

3. The offshore oil platform monitoring method based on Beidou high-precision positioning technology as claimed in claim 2, characterized in that: After completing the cycle slip detection, the processed carrier phase observation value is subjected to ambiguity fixing, including: Establish the double-difference observation equation of BeiDou B1C signal and select the reference station with the best signal quality as the main reference station; When the satellite elevation angle is lower than a second preset angle, the observation value of the satellite is eliminated from the double difference observation equation; Performing tropospheric delay correction on the double-difference observation equation; A floating-point solution estimation model is constructed by using a sequential least squares method. When the variance cofactor of the floating-point solution estimation is less than a first preset value and the redundancy of the observation equation is greater than a second preset value, an ambiguity search is initiated to obtain a candidate integer solution set. A ratio test method is used to evaluate the reliability of the candidate integer solution set, and if it passes the judgment, the ambiguity fixing result associated with the carrier phase observation value is accepted.

4. The offshore oil platform monitoring method based on Beidou high-precision positioning technology as claimed in claim 3 is characterized in that: The logic of obtaining the polynomial coefficients of each segment of the curve is as follows: The linear equations are transformed into a tridiagonal matrix equation in the standard form of the pursuit method, and the pursuit method is used to solve them to obtain the second-order derivative values ​​at each node; The second-order derivative values ​​at each node are used to calculate the four coefficients of each curve; Sampling verification is performed on each curve segment to check whether the continuity conditions at the nodes are met. If not, the chasing method is used again to solve the problem. If satisfied, the polynomial coefficients of each curve segment are output. The catch-up method for solving the problem includes forward elimination, starting from the first equation, gradually eliminating the lower diagonal elements, and recording the elimination multipliers; after the forward elimination is completed, back substitution is performed, starting from the last equation, and each unknown number is solved in turn; if an abnormal value appears in the solution of an unknown number, the coefficients of the equation group are rechecked.

5. The offshore oil platform monitoring method based on Beidou high-precision positioning technology as claimed in claim 4, characterized in that: The calculation of the fitting residual is shown in the following formula: ； Among them, the weight function : ； in, is the optimized fitting residual value, is the total number of measurement points, is the measured value of the ith measuring point, is the spline function fitting value, is the weight function, is the distance from the ith measuring point to the adjacent node, is the value of the elevation change influence coefficient, is the distance attenuation coefficient value, is the elevation difference between adjacent measuring points, is the horizontal distance between adjacent measuring points.

6. The offshore oil platform monitoring method based on Beidou high-precision positioning technology as claimed in claim 5, characterized in that: The floating point solution estimation model is expressed as follows: ； Among them, the weight function : ； Among them, the variance adjustment function : ； in, is the floating-point solution estimate for the current epoch, is the number of effective satellites, is the observation weight coefficient of the i-th satellite, is the elevation angle of the ith satellite, is the signal-to-noise ratio of the ith satellite, is the variance cofactor of the current epoch, is the observation value of the i-th satellite.

7. A marine oil platform monitoring system based on Beidou high-precision positioning technology, based on the marine oil platform monitoring method based on Beidou high-precision positioning technology according to any one of claims 1 to 6, characterized in that: include, A collection module is used to arrange Beidou enhanced anti-interference receiving units at the bottom, middle and top of the columns of the offshore oil platform to collect Beidou B1C signal data of the columns; A spatial coordinate calculation module, which is used to perform differential analysis on the B1C signal data using a multi-base station network RTK technology, cooperate with a circular antenna array to suppress sea surface scattering interference, and output spatial coordinate values ​​of the three measuring points of the column; A maximum lateral displacement extraction module is used to calculate the bending deformation curve of the column by piecewise curve fitting based on the spatial coordinate values ​​of the three measuring points of the column, and to extract the maximum lateral displacement of the column; The alarm module is used to generate an alarm message of excessive deformation of the column when the maximum lateral displacement of the column is continuously greater than a preset length within 10 minutes and the angle between the displacement direction and the wind direction is less than a first preset angle.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the offshore oil platform monitoring method based on Beidou high-precision positioning technology described in any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the offshore oil platform monitoring method based on Beidou high-precision positioning technology described in any one of claims 1 to 6 are implemented.

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