Offshore oil platform monitoring method and system based on Beidou high-precision positioning technology

Abstract

The invention discloses an offshore oil platform monitoring method based on a Beidou high-precision positioning technology, and relates to the field of ocean engineering, and the method comprises the steps: arranging a Beidou enhanced anti-interference receiving unit, and collecting Beidou B1C signal data of a stand column; carrying out differential calculation on the B1C signal data, inhibiting sea surface scattering interference in cooperation with an annular antenna array, and outputting space coordinate values of three measuring points of the stand column; based on the space coordinate values of the three measuring points of the stand column, a bending deformation curve of the stand column is calculated through segmented curve fitting, and the maximum transverse displacement of the stand column is extracted; when the maximum transverse displacement of the stand column is continuously larger than the preset length within 10 minutes and the included angle between the displacement direction and the wind direction is smaller than a first preset angle, stand column excessive deformation alarm information is generated. According to the invention, the problems of large signal interference, insufficient positioning precision and difficulty in realizing real-time global deformation monitoring in a complex marine environment in the prior art can be effectively solved, so that the reliability and the precision of safety monitoring of an offshore oil platform structure are remarkably improved.

Description

Technical Field

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

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

[0003] However, the current structural monitoring technology for offshore oil platforms still has many shortcomings. Traditional monitoring methods mostly rely on manual regular detection or installation of fixed sensors to obtain physical parameters such as deformation and tilt of the platform structure. These methods are limited by the complexity of instrument layout, the lack of real-time monitoring data, and the influence of environmental interference, and cannot provide reliable monitoring results in harsh marine 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 remote areas, and satellite signals are affected by factors such as multipath 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 measuring point or multiple independent measuring points, lack a global analysis of the overall structural deformation of the platform, and are difficult to timely and accurately assess the stress state and safety status of the platform in a complex environment. 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] In order to solve the above technical problems, the present invention provides the following technical solutions: In a first aspect, an embodiment of the present invention provides a method for monitoring an offshore oil platform based on Beidou high-precision positioning technology, which comprises: 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.

[0006] As a preferred solution of the offshore oil platform monitoring method based on Beidou high-precision positioning technology described in the present invention, wherein: 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.

[0007] As a preferred solution of the offshore oil platform monitoring method based on Beidou high-precision positioning technology described in the present invention, after completing the cycle slip detection, the ambiguity of the processed carrier phase observation value is fixed, 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. The reliability of the candidate integer solution set is evaluated by using a ratio test method, and if it passes the judgment, the set of ambiguity fixing results is accepted.

[0008] As a preferred solution of the offshore oil platform monitoring method based on Beidou high-precision positioning technology of the present invention, 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.

[0009] As a preferred solution of the offshore oil platform monitoring method based on Beidou high-precision positioning technology described in the present invention, 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 segment; Sampling and verifying 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.

[0010] As a preferred solution of the offshore oil platform monitoring method based on Beidou high-precision positioning technology of the present invention, 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.

[0011] As a preferred solution of the offshore oil platform monitoring method based on Beidou high-precision positioning technology described in the present invention, the floating point solution estimation model can be expressed by the following formula: ; 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.

[0012] 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: The acquisition module is used to respectively 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.

[0013] In a third aspect, an embodiment of the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the processor executes the computer program, it implements any step of the above-mentioned marine oil platform monitoring method based on Beidou high-precision positioning technology.

[0014] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium on which a computer program is stored, wherein: when the computer program is executed by a processor, any step of the above-mentioned marine oil platform monitoring method based on Beidou high-precision positioning technology is implemented.

[0015] The beneficial effect of the present invention is to combine Beidou high-precision positioning technology with multi-base station network RTK technology, innovatively deploy Beidou enhanced anti-interference receiving units at the bottom, middle and top of the offshore oil platform columns, collect and process Beidou B1C signal data in real time, and use the circular antenna array to effectively suppress sea surface scattering interference to ensure the acquisition of high-precision spatial coordinates. Further, the bending deformation curve and maximum lateral displacement of the column are accurately calculated by the segmented curve fitting method, and the real-time early warning of excessive deformation of the platform structure is realized in combination with wind direction data. The scheme has significant improvements in key technologies such as multipath interference suppression, cycle slip detection and repair, ambiguity fixation and accuracy and robustness of fitting algorithms, which 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 under complex marine environments, thereby significantly improving the reliability and accuracy of offshore oil platform structural safety monitoring, and providing important technical guarantees for the efficient operation and safety management of the platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them: Figure 1 This is a flow chart of the offshore oil platform monitoring method based on Beidou high-precision positioning technology. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0018] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0019] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0020] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0021] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are 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 direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" 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, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] Embodiment 1: Reference Figure 1 , which is the first embodiment of the present invention, provides a method for monitoring an offshore oil platform based on Beidou high-precision positioning technology, comprising: S1. Beidou enhanced anti-interference receiving units are 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 sampling frequency of the B1C signal data is 2Hz; A Beidou enhanced anti-interference receiving unit is fixedly installed at the bottom of each column of the offshore oil platform at 1.5 meters from the sea level, at the middle at 35 meters from the sea level, and at the top at 70 meters from the sea level. The anti-interference receiving unit adopts a built-in microstrip antenna array structure, and the microstrip antenna array is composed of 8 ceramic substrate antenna elements evenly distributed in a ring. The center frequency of the ceramic substrate antenna element is 1575.42MHz and the bandwidth is 40MHz; the shell of the anti-interference receiving unit is made of 316L stainless steel, the surface is treated with Teflon coating, has an IP67 protection level, and can work stably in the temperature range of -40℃ to 85℃; the anti-interference receiving unit integrates a 72-channel RF front-end circuit, and the RF front-end circuit includes a low-noise amplifier, a bandpass filter and an analog-to-digital converter, wherein the noise coefficient of the low-noise amplifier is less than 1.5dB and the gain is 35dB; the anti-interference receiving unit It is connected to the signal processing host through a military-grade waterproof aviation plug. The aviation plug adopts an all-metal sealing structure and the sealing ring is made of fluororubber. The signal processing host adopts a TMS320C6678 processor with a main frequency of 1.25GHz and a built-in independently developed space-time adaptive interference detection and suppression algorithm. The algorithm adopts the minimum variance distortion-free response criterion. The anti-interference receiving unit collects Beidou III B1C signal data. The B1C signal data includes a pilot component and a data component, wherein the pilot component adopts BOC (1,1) modulation with a code rate of 1.023Mbps, and the data component adopts QPSK modulation with a code rate of 1.023Mbps. The sampling frequency of the B1C signal data is set to 2Hz, that is, a complete phase observation value and pseudo-range observation value are collected every 0.5 seconds, wherein the accuracy of the phase observation value is better than 0.1 cycle, and the accuracy of the pseudo-range observation value is better than 0.1 meter.

[0024] S2. Using multi-base station network RTK technology to perform differential decomposition on the B1C signal data, with the ring antenna array to suppress sea surface scattering interference, output the spatial coordinate values ​​of the three measuring points of the column; The B1C signal data is differentially analyzed using a multi-base station network RTK technology consisting of 6 reference stations, wherein the reference stations are distributed in a regular hexagon with the platform to be monitored as the center, and the distance between adjacent reference stations is 15 kilometers. Each of the reference stations is equipped with a BeiDou-III full-frequency receiver and a cesium atomic clock, and the frequency stability of the cesium atomic clock is better than 5×10^-13; the reference stations are interconnected through submarine optical cables, and the optical cables adopt a steel wire armored reinforced structure with a transmission delay of less than 0.5 milliseconds.

[0025] The differential decomposition process is divided into three stages that are executed sequentially: In the first stage, cycle slip detection is performed. When the B1C signal data enters the cycle slip detection module, the Doppler shift prediction value is first constructed, and the Doppler shift prediction value is calculated based on the carrier phase observation values ​​of the previous three epochs; then the Doppler shift prediction value is compared with the actual carrier phase observation value 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 inspection. The ionospheric residual third-order difference method combines the carrier phase observations and pseudorange observations of four consecutive epochs to form an ionospheric combined observation. When the inter-epoch difference of the ionospheric combined observation exceeds a threshold of 0.3 cycles, it is confirmed as a cycle slip point. If the cycle slip point is found, the adaptive Kalman filter repair module is called, and the adaptive Kalman filter repair module calculates the cycle slip size according to the carrier phase observations of the previous and next epochs. After the cycle slip repair is completed, the repair result is subjected to a residual test, and the residual test adopts the Chi-square test method. When the residual exceeds the 95% confidence interval, the repair result is marked as invalid, and the epoch data is eliminated in the subsequent solution. The sampling interval of the 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 the cycle slip detection. The data output by the cycle slip detection module includes three parameters: a cycle slip mark, a repair mark, and a quality index. The quality index reflects the reliability of the cycle slip detection, and the value range is 0-100.

[0026] In the second stage, ambiguity fixation is performed. After the cycle slip detection and repair are completed, the ambiguity of the processed carrier phase observation value is fixed. First, the 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. When the satellite elevation angle is lower than 15 degrees, the observation value of the satellite is automatically removed from the double difference observation equation.

[0027] Then, the Saastamoinen model is used to correct the tropospheric delay of the double-difference observation equation; then, the sequential least squares method is used to construct a floating-point solution estimation model, in which the weight coefficient of the observation value is calculated according to the satellite elevation angle and the signal-to-noise ratio. When the variance cofactor 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 Z-transform decoration on the floating-point solution covariance matrix, and the condition number of the decorated covariance matrix is ​​made less than 100 by the Lovász reduction algorithm; then, the shrinkage factor method is used in the decorated search space to determine the candidate solution region, and the shrinkage factor is adaptively adjusted according to the correlation between epochs, and the value range is 0.5-0.9; after obtaining the set of candidate integer solutions, the reliability of ambiguity fixation is evaluated by the ratio test method, and the ratio of the residual sum of squares of the optimal solution and the suboptimal solution is calculated. If the ratio is greater than 3 and the posterior unit weighted mean error of the optimal solution is less than 0.8, the set of ambiguity fixation results is accepted; for the reliably fixed ambiguity, a partial fixation strategy is adopted. When the standard deviation of a single ambiguity is greater than 0.15 cycles, it is maintained in a floating-point solution state; the time window for ambiguity fixation is 5 seconds. If a reliable fixed solution cannot be obtained within a time window, the floating-point solution state is maintained and the data of the next time window is waited; finally, the ambiguity fixation result is output, including a fixed solution state identifier, an ambiguity integer value and a fixed reliability index.

[0028] The general expression of the floating point solution estimation model can be expressed as follows: ; Among them, the weight function is: ; Among them, the variance adjustment function is: ; 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 (radians), is the signal-to-noise ratio of the ith satellite (dB-Hz), is the variance cofactor of the current epoch, is the observation value of the i-th satellite.

[0029] It is worth noting that although the above description outlines the general process of ambiguity fixation, in actual engineering applications, there may be a variety of complex situations that require special processing. For example, when the monitoring platform is located at sea, the sea surface multipath effect will significantly affect the quality of the observation value. At this time, it is necessary to introduce a multipath correction term in the double difference observation equation. Specifically, if the observation 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 the observation value, and even eliminate it if necessary.

[0030] During the floating point solution estimation phase, the processing strategies will be different under different environmental conditions. 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 the satellite distribution geometry is poor (such as PDOP value greater than 6), the system will automatically extend the observation time until the geometric strength improves before calculating the fixed solution.

[0031] The specific implementation of the ambiguity search process also varies depending on the actual conditions. For example, in a good signal condition (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 obstructions or electromagnetic interference), it may take multiple epochs of data to complete the ambiguity fixation.

[0032] The third stage is to calculate the spatial coordinate values. After obtaining the fixed solution, the weighted least square adjustment algorithm is used to calculate the spatial coordinate values ​​of the three measuring points of the column.

[0033] In more detail, after obtaining a reliable ambiguity fixation solution, when the weighted least squares adjustment algorithm is used to calculate the spatial coordinate values ​​of the three measuring points of the column, an observation error equation is first established, the error equation includes the fixed carrier phase observation value and the pseudorange observation value, wherein 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 observation residual of a certain satellite exceeds 3 times the mean error, the weight coefficient of the observation value is reduced to 50% of the original; then a coefficient matrix is ​​constructed, the elements of the coefficient matrix are calculated by the satellite position and the approximate position of the receiver, wherein the satellite position is calculated using precise ephemeris, and the time delay of the precise ephemeris does not exceed 30 seconds.

[0034] Then, the weighted least square adjustment equation is solved by an iterative method, and the iteration is stopped when the difference between two adjacent iterative solutions is less than 1 mm or the number of iterations reaches 10; the variance component of the adjustment result is estimated, and the accuracy index of the positioning result is calculated, including the standard deviation in the three directions of east, north and elevation; when the horizontal standard deviation is greater than 2 cm or the elevation standard deviation is greater than 3 cm, the observation value is re-screened, and the abnormal observation value with the largest contribution value is eliminated and the adjustment calculation is re-performed; the adjustment calculation adopts the 2000 National Geodetic Coordinate System, firstly obtains the coordinate value under the geodetic coordinate system, and then converts it into three components of longitude, latitude and geodetic height; considering the fixed relative position characteristics of the three measuring points of the column, the distance constraint between the measuring points is introduced in the adjustment process, and the weight coefficient of the distance constraint is set to 100, and an abnormal warning is issued when the distance between the points after adjustment exceeds 5 mm; finally, the coordinate value of the measuring point and its accuracy index are output, and the accuracy index includes the standard deviation of the coordinate component and the point error ellipse parameter.

[0035] It is worth noting that although the above description outlines the general process of differential analysis of multi-base station network RTK technology, the specific implementation details may vary depending on different monitoring environments and hardware configurations. For example, in typhoon weather, strong winds may cause the antenna to shake slightly. At this time, the system will automatically increase the sampling rate of the carrier phase observation value from the standard 2Hz to 5Hz or higher to better capture the platform's small movements. If there is heavy rainfall, the system will increase the weight of tropospheric delay correction and may enable the multipath effect monitoring module to cope with the impact of raindrops on signal propagation. It is particularly worth mentioning that the application of ring antenna arrays greatly improves the system's anti-interference ability. For example, when the sea surface is windy and rough, the intensity and direction of the reflected signal will change dramatically. At this time, the antenna array can adjust the beam direction in real time to maintain effective suppression of interference signals. In actual engineering, there have been cases that show that this technology can reduce the positioning error caused by sea surface reflection from centimeters to millimeters.

[0036] S3. 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; The coordinate values ​​of the three measuring points solved by RTK 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 as the Z axis, the eastward as the X axis, and the northward as the Y axis.

[0037] 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-RTK solve the measuring point; check the distance between the measuring points. When the distance between adjacent measuring points is greater than 10 meters, add a node between the two measuring points using the equidistant principle.

[0038] Furthermore, two-dimensional curve fitting is performed in the XOZ plane and the YOZ plane respectively, using piecewise cubic spline function, requiring: The function values ​​of adjacent segments are continuous at the nodes; The first-order derivatives of adjacent segments are continuous at the nodes; The second-order derivatives of adjacent segments are continuous at the nodes; The angle between the tangent direction at the bottom of the column and the vertical direction is less than 0.1 degrees; The established piecewise cubic polynomial equation group is solved by the chasing method to obtain the polynomial coefficients of each curve segment; the fitting residual at the measuring point is calculated. When the residual root mean square value is greater than 3 mm, it is necessary to adjust the node position or increase the number of nodes and then re-fit.

[0039] The displacement values ​​are calculated at intervals of 0.1 meters on the fitted curve, and the following are obtained: The maximum displacement in the X direction and its location; The maximum displacement in the Y direction and its location; The displacements in the X and Y directions are synthesized to obtain the combined displacement in the horizontal plane; Determine the maximum value of the combined displacement, which is the maximum lateral displacement of the column.

[0040] In more detail, the logic of obtaining the polynomial coefficients of each segment of the curve is as follows: First, a cubic polynomial expression is established for each curve segment. Each curve segment contains four undetermined coefficients, and equations are established for adjacent curve segments through continuity conditions at the nodes. When there are n nodes, n-1 curve segments 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 function value continuity, first-order derivative continuity, and second-order derivative continuity, 3 (n-2) equations are established. Fixed end constraints are imposed at the bottom of the column to provide 2 equations. Free end constraints are imposed at the top to provide 2 equations. Thus, a complete set of linear equations is obtained.

[0041] Next, the linear equations are transformed into a tridiagonal matrix equation in the standard form of the pursuit method, and then solved using the pursuit method. First, forward elimination is performed, starting from the first equation, and the lower diagonal elements are gradually eliminated, while the elimination multipliers are recorded. When the forward elimination is completed, back substitution is performed, starting from the last equation, and each unknown is solved in turn. If an abnormal value (more than 100 times the expected range) appears in the solution of an unknown, the coefficients of the equation group are rechecked.

[0042] After obtaining the second-order derivative value at each node, substitute it into the piecewise cubic polynomial expression to calculate the four coefficients of each curve segment; perform sampling verification on each curve segment to check whether the continuity condition at the node is met. When the deviation of the continuity condition exceeds 10^-6, the catch-up method needs to be re-solved; finally, the polynomial coefficients of each curve segment are output. The coefficients of the piecewise cubic polynomial can fully express the deformation state of the column at any height, and the displacement value can be obtained through the polynomial coefficients.

[0043] For example, for height Z, first determine the curve segment it is on. Assume that in segment i, the polynomial coefficient of the segment is a i 、b i 、c i ,d i .

[0044] Substituting Z into the polynomial equation for the segment: X-direction displacement = a i (ZZ i )³ + b i (ZZ i )² + c i (ZZ i ) + d i ; The Y-direction displacement is calculated in the same way, but using the polynomial coefficients in the Y direction; Starting from the bottom of the column (Z=0), calculate the X and Y displacement values ​​of a position every 0.1 meters: Z = 0, 0.1, 0.2, ..., H meters (H is the total height of the column); A series of discrete displacement values ​​can be obtained.

[0045] For each calculated position, the displacements in the X and Y directions are synthesized: Resultant displacement = √(X displacement² + Y displacement²); By comparing the composite displacements of all calculated positions, the maximum value and its corresponding height position are found, so that the complete deformation information of the column along the height direction can be accurately obtained.

[0046] It should be noted that the general formula for calculating the fitting residual at the measuring point can be expressed as follows: ; Among them, the weight function is: ; 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, The value of the elevation change influence coefficient is 0.1. The distance attenuation coefficient is set to 0.05. is the elevation difference between adjacent measuring points, is the horizontal distance between adjacent measuring points. The residual value directly reflects the degree of fit between the fitting curve and the measured points. The fitting residual value is used to judge whether the fitted curve meets the requirements and whether the obtained maximum lateral displacement is accurate. If the fitting residual value does not meet the requirements, the curve needs to be refitted.

[0047] When the maximum lateral displacement of the column is continuously greater than 15 cm within 10 minutes, and the angle between the displacement direction and the wind direction is less than 30 degrees, an alarm message of excessive deformation of the column is generated.

[0048] Furthermore, this embodiment also provides an offshore oil platform monitoring system based on Beidou high-precision positioning technology, including: The acquisition module is used to respectively 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.

[0049] This embodiment also provides a computer device, which is suitable for the offshore oil platform monitoring method 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 computer-executable instructions to implement the offshore oil platform monitoring method based on Beidou high-precision positioning technology as proposed in the above embodiment.

[0050] The computer device may be a terminal, and the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the 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 the 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, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covering the display screen, or a key, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0051] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method for monitoring an offshore oil platform based on Beidou high-precision positioning technology as proposed in the above embodiment is implemented.

[0052] 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 fully described in this embodiment can be found in the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0053] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in 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.

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. The reliability of the candidate integer solution set is evaluated by using a ratio test method, and if it passes the judgment, the set of ambiguity fixing results 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: 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.

5. The offshore oil platform monitoring method based on Beidou high-precision positioning technology as claimed in claim 4, 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 segment; Sampling and verifying 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.

6. 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.

7. The offshore oil platform monitoring method based on Beidou high-precision positioning technology as claimed in claim 6, characterized in that: The floating point solution estimation model can be 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.

8. An offshore oil platform monitoring system based on Beidou high-precision positioning technology, based on the offshore oil platform monitoring method based on Beidou high-precision positioning technology according to any one of claims 1 to 7, characterized in that: include, The acquisition module is used to respectively 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.

9. 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 7 are implemented.

10. 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 7 are implemented.

Images