Ocean buoy observation carrier attitude correction method and system based on multi-antenna Beidou

Abstract

The invention belongs to the technical field of ocean measurement, and discloses an ocean buoy observation carrier attitude correction method and system based on a multi-antenna Beidou. The method comprises the following steps: acquiring Beidou observation data of four Beidou receiver antennas on a buoy; after data preprocessing, gross error elimination and detection cycle slip are carried out, high-precision dynamic baseline vector calculation is carried out by adopting a dynamic-dynamic differential mode, and baseline vector values among four Beidou receiver antennas are obtained; detecting and weakening gross error results in baseline vectors through baseline length priori constraint and dynamic unconstrained network adjustment solution, and obtaining independent baseline vector results of the four Beidou receiver antennas; obtaining a current real-time attitude result by using the baseline vector calculated in real time; and after buoy attitude correction is carried out based on the buoy physical parameters, a precise buoy geodetic elevation observation result is obtained. According to the invention, the applicability and accuracy of the ocean buoy under severe sea conditions are improved.

Description

Technical Field

[0001] The present invention belongs to the field of ocean measurement technology, and in particular relates to an attitude correction method and system for an ocean buoy observation carrier based on a multi-antenna Beidou. Background Art

[0002] With the rapid development of marine scientific research and maritime transportation, ocean buoys, as an important tool for marine environment monitoring, are widely used in meteorological, oceanographic, environmental and other data collection tasks.

[0003] The attitude of the buoy (including heading, pitch and roll) has an important influence on the accuracy of the buoy's positioning, direction and motion trajectory. However, due to the complexity of the buoy's working environment, including sea surface fluctuations, strong currents, and the dynamic drift of the buoy itself, the buoy's attitude is usually easily disturbed, resulting in a decrease in its attitude accuracy, which in turn affects the reliability of the measurement results.

[0004] At present, the traditional ocean buoy attitude monitoring method mainly relies on a single inertial measurement unit (IMU), gyroscope, accelerometer and other sensors to calculate the attitude. However, these sensors often have problems such as low accuracy, large drift, and sensitivity to environmental noise. In some extreme marine environments, the error accumulation of these sensors will lead to serious deviations in attitude, affecting the normal operation of the buoy.

[0005] In recent years, the application of Beidou satellite navigation system in ocean measurement has gradually gained attention. Beidou has high-precision positioning function and can provide more accurate positioning data for ocean buoys. However, since ocean buoys often change their attitude in a dynamic environment, a single Beidou receiver antenna cannot directly provide real-time attitude information of the buoy. Therefore, how to use Beidou receivers with multiple antennas to obtain the carrier attitude and perform real-time attitude correction has become a key issue in the current accurate monitoring of ocean buoy attitude. Summary of the invention

[0006] In order to overcome the problems existing in the related technologies, the disclosed embodiments of the present invention provide a method and system for correcting the attitude of an ocean buoy observation carrier based on a multi-antenna Beidou, aiming to provide a low-cost, highly reliable and high-precision ocean carrier attitude solution and correction system, and utilize low-cost multi-antenna Beidou equipment to achieve real-time and high-precision absolute attitude measurement of marine carriers, greatly improve the operating efficiency and accuracy of marine carriers, reduce the cost of manpower regular maintenance, and improve the level of intelligence in marine operations.

[0007] To achieve the above purpose, the technical solution is as follows: A method for correcting the attitude of an ocean buoy observation carrier based on a multi-antenna BeiDou comprises the following steps: S101, using the Beidou receiver in the Beidou receiver data acquisition system, obtain Beidou observation data of four Beidou receiver antennas on the buoy; and receive data from the Beidou reference station on shore, perform differential positioning between the Beidou main antenna on the buoy and the Beidou reference station on shore, and obtain a differential positioning result of the buoy main antenna relative to the reference station; S102, the real-time Beidou observation data of the buoy is preprocessed to remove gross errors and detection cycle slips, and then a high-precision dynamic baseline vector solution is performed using a dynamic difference mode to obtain the initial value of the baseline vector between the four Beidou receiver antennas; S103, based on the baseline network data of four Beidou receiver antennas acquired in real time, using baseline length priori constraints and dynamic unconstrained network adjustment solution, detect and weaken gross errors and closure errors in the initial value results of baseline vector solution; S104, using the real-time baseline vector results between the four antennas calculated, through coordinate conversion, to obtain the real-time attitude angles of the current carrier in the heading, roll and pitch directions; S105, after buoy attitude correction based on the physical parameters of the buoy, obtain precise buoy geodetic height observation results; based on the real-time three-dimensional attitude angle information of the GNSS system, provide real-time attitude correction values ​​for the ocean buoy observation carrier, ensure the vertical measurement of the ocean surface height by the equipment on the buoy carrier, correct the height error caused by the tilt of the buoy body due to the influence of wave surges, and eliminate the systematic offset error caused by the attitude angle correction based on inertial equipment measurement.

[0008] In step S101, the Beidou receiver data acquisition system includes: a buoy, a Beidou receiver, a Beidou receiver antenna, a data acquisition module and a power module; Four BeiDou receivers are deployed on the buoy in a symmetrical cross arrangement. The four BeiDou receivers are connected to four external BeiDou receiver antennas. The data acquisition module performs data storage and data transmission; The power module uses a combination of solar panels and batteries as the power supply system.

[0009] In step S102, the initial value of the baseline vector between the four Beidou receiver antennas is obtained, including: S1021, for the collected Beidou observation data, the gross errors are processed a posteriori by means of detection, identification and adjustment; S1022: for the Beidou observation data that has been removed from the rough inspection, the dual-frequency code phase combination method and the ionospheric residual method are used to detect cycle slips; S1023, using the dynamic differential mode to perform high-precision dynamic baseline vector solution to obtain the baseline vector value between the four Beidou receiver antennas; S1024, using the integer ambiguity reduction correlation integer least squares estimation LAMBDA algorithm to resolve the ambiguity and obtain an integer solution.

[0010] In step S1021, the gross errors are processed a posteriori by means of detection, identification, and adjustment, including: In the detection phase, the data is tested through statistics, the redundant number of observations and the variance matrix are calculated, and the chi-square test is used to determine whether there are abnormal data; if the test is significant, the identification step is entered; if not significant, the detection is stopped; In the identification stage, the test statistic is constructed by standardizing the residual. The test value exceeding the significance level indicates that a certain observation value is abnormal data. After removing the value, re-adjustment is performed and the overall test is performed. If there is still an abnormality, continue to identify until the global test passes. The adjustment phase uses the remaining observations to perform least squares estimation, and finally obtains the result and outputs it.

[0011] In step S1023, the dynamic differential mode includes: using two Beidou receiver antennas installed on the moving carrier to perform differential processing, the coordinates of the Beidou receiver antenna as the reference station are not set to fixed values, and the results of real-time dynamic positioning are used; the Beidou receiver as the mobile station performs differential processing with the reference station to solve and obtain the baseline vector of the mobile station relative to the reference station; The dynamic differential mode is used to perform high-precision dynamic baseline vector solution to obtain the baseline vector between the four Beidou receiver antennas; in the double-difference observation model, at the same time, the two receivers perform differential observations of the same satellite to eliminate the common errors between the receivers; the same receiver performs differential observations of two different satellites at two different times to eliminate the common errors between the satellites; the constructed satellite station double-difference model is: ; ; In the formula, is the double-difference pseudo-range observation value of the satellite station at time 𝑡, in meters, is the double-difference geometric distance of the star stations at time 𝑡, is the double-difference ionospheric error of the satellite station at time 𝑡, is the double-difference tropospheric error of the satellite station at time 𝑡, is the other error term of the double difference of the satellite station at time 𝑡, in meters, is the double-difference carrier phase observation value of the satellite station at time 𝑡, in weeks, is the station double difference of the weekly ambiguity determined at the initial epoch t_0, in weeks, The rover and non-reference satellite numbers are are the reference station and reference satellite numbers, respectively. is the original pseudorange observation from the satellite to the receiver, in meters; is the spatial geometric distance from the satellite to the receiver, in meters; are the ionospheric and tropospheric errors, respectively. For other errors, is the integer ambiguity value in the carrier phase observation value, in weeks; is the wavelength of the frequency.

[0012] In step S1024, the integer ambiguity reduction correlation integer least squares estimation LAMBDA algorithm is used to resolve the ambiguity and obtain an integer solution, including: converting the variance covariance matrix of the floating-point solution ambiguity value to achieve integer reduction correlation, weakening the correlation between the floating-point solution ambiguities, reducing the ambiguity search space, and achieving rapid ambiguity fixation; the specific steps are: (a) Without external constraints, the parameter solution is obtained by using the least squares method to solve the Beidou double-difference observations obtained from multiple baselines through double-difference observation data. and and the cofactor matrix , the Beidou double difference observation equation obtained from multiple baselines is: ; ; In the formula, is the observation equation, is the unknown double difference parameter of the baseline, , for The double difference parameters of the baseline are unknown; is the unknown parameter of the baseline length, , For the The unknown baseline length parameter of the baseline; for The unknown double difference parameter matrix of the baseline, for Contains The matrix of baselines, is the covariance of the observation vector, is the covariance matrix of the observations; , for Code and phase linearized observation vectors of the baseline; for The ambiguity coefficient matrix, for The mapping matrix, is the cofactor matrix between baselines, is the cofactor matrix of pseudorange and phase, for product; (b) Construct the optimal problem for fuzzy search, expressed as: ; ; In the formula, is the optimal integer ambiguity solution, is the dimension of the search space, is the vectorized operation of the matrix, is the floating point solution for the ambiguity, is the weighted Euclidean norm, which measures and The weighted distance between is a constraint set, representing the set of all possible ambiguity solutions, is a given constant used to define the size of the search space; By search criteria Under the constraint of The nearest blur vector; (c) The LAMBDA algorithm converts the initial and ambiguity float solution Perform Gaussian orthogonal transformation to reduce the internal correlation of the floating-point solution ambiguity, perform correlation reduction processing on the floating-point solution, and finally obtain an integer solution; ; ; In the formula, is the integer ambiguity vector obtained by transformation, is the orthogonal transformation matrix The transpose of is the orthogonal transformation matrix The transpose of is the integer ambiguity vector The covariance matrix of is an orthogonal integer transformation matrix with a modulus of 1, and after the transformation The off-diagonal elements of are less than or equal to 0.5; (d) Test and back-substitution of the integer ambiguity, using the significance ratio test and setting the threshold Value, test the ratio of the second smallest value to the smallest value , if the test value If it is greater than the threshold, the fuzzy search is correct; ; In the formula, is the second minimum value of the objective function, is the minimum value of the objective function, the optimal integer ambiguity solution The objective function value of It is a pre-set threshold, and its value range is generally 2 to 3; It is believed that The corresponding integer ambiguity value is the correct ambiguity combination.

[0013] In step S103, based on the four Beidou receiver antenna baseline network data acquired in real time, the baseline length priori constraint and the dynamic unconstrained network adjustment solution are used to detect and weaken the gross errors and closure errors in the initial value results of the baseline vector solution, and obtain the four Beidou receiver antenna independent baseline vector results with high precision and high reliability; specifically, it includes: S1031, dynamic baseline solution based on baseline length constraint; Added pseudo-measurement equation measurement value , measurement equation , observation matrix , the covariance of the measurement noise They are: ; ; ; ; In the formula, is the baseline length, is the position of the rover, is the signal receiving time, is the location of the base station, is the error in the baseline length, To represent transpose; S1032, dynamic baseline solution based on dynamic unconstrained network adjustment solution; According to the error equation, the reference equation and the equation-covariance matrix, the adjustment is performed according to the least squares principle to obtain the adjusted result: ; In the formula, is the parameter correction number after adjustment, is the coefficient matrix, For transposition, is the covariance matrix of the observations The inverse matrix of is the coefficient matrix of the benchmark equation, is the error vector of the observed value; Coordinates of each point after adjustment It is expressed as: ; In the formula, is the initial coordinate value before adjustment; The unit weighted mean error after adjustment is: ; In the formula, is the number of baselines that make up the Beidou network. is the total number of measuring stations involved in the adjustment, is the unit weight error, is the correction vector.

[0014] In step S104, the real-time baseline vector results between antennas obtained by solving the four antennas are used to obtain the real-time attitude angles of the current carrier in the heading, roll and pitch directions through coordinate conversion; including: S1041, relationship between the baseline vector in the carrier coordinate system and the navigation coordinate system; ; In the formula, are the baseline vectors in the navigation coordinate system and the carrier coordinate system respectively, is the attitude transfer matrix from the carrier coordinate system to the navigation coordinate system; S1042, direct method to solve the approximate values ​​of heading angle, pitch angle and roll angle , , ; S1043, using the relationship of rotation transformation, the least square method is used to perform posture calculation to obtain the posture information of the carrier.

[0015] In step S105, after the buoy attitude is corrected based on the buoy physical parameters, a precise buoy geodetic height observation result is obtained, including: S1051, based on the data of the BeiDou reference station on the shore, dynamically solves the baseline formed by the multi-antenna of the offshore buoy to obtain the instantaneous geodetic elevation of the phase center of the BeiDou main antenna of the buoy ; S1052: Perform attitude calculation based on the dynamic baseline vector between Beidou receiver antennas to obtain the tilt angle of the buoy , the roll angle on the buoy carrier is known and pitch angle , there are unit vectors in the directions of roll angle, pitch angle and heading angle, then the coordinate vectors of the unit vectors in the directions of roll angle and pitch angle in the carrier coordinate system are: ; ; In order to estimate the inclination angle of the buoy carrier, determine the angle between the normal line of the plane where the unit vectors of the roll angle and the pitch angle are located and the plumb line, then the direction vector With normal vector The relationship satisfies: ; The vector defining the direction of the plumb line is , then add a condition here, let the normal vector of The axis direction is positive and the value is 1; get the normal vector , the normal vector and The angle is the inclination angle of the buoy carrier , the expression is: ; In the formula, is the vector in the direction of the plumb line; S1053, based on the measurement results, multi-antenna Beidou sea level height The calibration formula of sea level height is expressed as: ; In the formula, is the instantaneous geodetic elevation of the phase center of the Beidou main antenna of the buoy, is the height from the phase center of the Beidou receiver antenna to the water surface.

[0016] Another object of the present invention is to provide an ocean buoy observation carrier attitude correction system based on multi-antenna Beidou, the system implements the ocean buoy observation carrier attitude correction method based on multi-antenna Beidou, the system comprises: Beidou receiver data acquisition system is used to deploy Beidou receiver equipment and collect observation data to obtain observation data; it also receives data from the Beidou reference station on shore, performs differential positioning between the Beidou main antenna on the buoy and the Beidou reference station on shore, and obtains the differential positioning result of the buoy main antenna relative to the reference station; The Beidou dynamic baseline precision processing module uses the dynamic differential mode to solve the baseline vectors of the four Beidou receiver antennas. Based on the baseline network data of the four Beidou receiver antennas acquired in real time, it detects and weakens the gross error results in the baseline vector through baseline length prior constraints and dynamic unconstrained network adjustment, and obtains high-precision and high-reliability independent baseline vector results of the four Beidou receiver antennas. The module for accurate buoy attitude estimation and correction obtains the current real-time attitude result by using the baseline vector calculated in real time. The buoy attitude result determined by the baseline vector is corrected by the initial attitude to eliminate the relative initial attitude error caused by the placement between the baseline network and the observation carrier platform. The module uses the accurate buoy attitude result obtained by the baseline network to correct the elevation error caused by the buoy attitude and obtains the accurate ocean buoy observation result after attitude correction. Combining all the above-mentioned technical solutions, the beneficial effects of the present invention are as follows: the present invention proposes a system and method for precise correction of the attitude of an ocean buoy based on a multi-antenna Beidou, which performs buoy attitude correction, obtains precise buoy geodetic elevation observation results, reduces the impact of complex sea conditions on the buoy height measurement results, and improves the applicability and accuracy of ocean buoys in severe sea conditions.

[0017] The present invention is used for accurate calibration of ocean buoy attitude, and mainly comprises a Beidou receiver data acquisition system, a Beidou dynamic baseline precision processing module, and a carrier attitude accurate estimation and correction module. The observation data of the four Beidou receiver antennas on the carrier are obtained by using an all-weather, real-time and high-precision Beidou receiver. The Beidou receiver antennas are symmetrically cross-distributed to obtain the maximum baseline length on the narrow observation platform as much as possible. After the Beidou observation data is preprocessed to eliminate gross errors and detection cycle slips, the dynamic baseline vector is solved with high precision using the dynamic difference mode to obtain the baseline vector value between the four Beidou receiver antennas. According to the baseline network data of the four Beidou receiver antennas obtained in real time, the gross error results in the Beidou baseline vector are detected and weakened through baseline length prior constraints and dynamic unconstrained network adjustment solution, and the independent baseline vector results of the four Beidou receiver antennas with high precision and high reliability are obtained. The baseline vector calculated in real time is used to obtain the current real-time attitude result. The attitude correction is performed based on the design parameters of the buoy observation carrier to obtain the precise ocean buoy observation results after attitude correction, reduce the influence of complex sea conditions on the results of the buoy carrier observation platform, and improve the applicability of ocean buoys in severe sea conditions.

[0018] The present invention adopts low-cost Beidou receivers and improved algorithms, which greatly reduce equipment costs and maintenance costs while ensuring accuracy, effectively extend the service life of the equipment, and effectively reduce the maintenance costs of marine equipment. It greatly promotes the application of low-cost buoys in marine observation and promotes the development of marine economic activities. Compared with traditional inertial equipment, it obtains absolute attitude information, provides a high-precision and high-reliability attitude observation system for domestic marine equipment, obtains precise marine buoy observation results after attitude correction, reduces the impact of complex sea conditions on the results of the buoy carrier observation platform, and improves the applicability of marine buoys in severe sea conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings herein are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the description, serve to explain the principles of the present disclosure; Figure 1 It is a flow chart of a method for correcting the attitude of an ocean buoy observation carrier based on multi-antenna Beidou provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of an attitude correction system for an ocean buoy observation carrier based on a multi-antenna BeiDou provided in an embodiment of the present invention; Figure 3 It is a schematic diagram of a method for correcting the attitude of an ocean buoy observation carrier based on multi-antenna Beidou provided in an embodiment of the present invention; Figure 4 It is a schematic diagram of four receivers provided by an embodiment of the present invention being installed on a buoy in a symmetrical cross shape; Figure 5 is a schematic diagram of a carrier coordinate system provided by an embodiment of the present invention; In the figure: 1. Beidou receiver data acquisition system; 2. Beidou dynamic baseline precision processing module; 3. Buoy attitude precision estimation and correction module. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0021] The innovation of the present invention is: (1) The present invention is used for accurate calibration of the attitude of ocean buoys, and mainly includes a Beidou receiver data acquisition system, a Beidou dynamic baseline precision processing module, and a carrier attitude precision estimation and correction module. The all-weather, real-time, high-precision Beidou receiver is used to obtain the observation data of the four Beidou receiver antennas on the carrier, and the dynamic differential mode is used to obtain a high-precision dynamic baseline vector; (2) Based on the baseline network data of the four Beidou receiver antennas obtained in real time, the baseline length prior constraints and dynamic unconstrained network adjustment are used to improve the accuracy of baseline vector solution and detect and eliminate gross errors, providing high-precision and high-reliability baseline vector observation values ​​for attitude measurement, and obtaining high-precision three-dimensional attitude values ​​of the carrier in real time; (3) Using the current real-time attitude results, based on the design parameters of the buoy observation carrier, the buoy attitude correction is performed to obtain precise ocean buoy observation results after attitude correction, thereby reducing the impact of complex sea conditions on the buoy carrier observation platform results and improving the applicability of ocean buoys in severe sea conditions.

[0022] Embodiment 1, as Figure 1 As shown, the method for correcting the attitude of an ocean buoy observation carrier based on a multi-antenna BeiDou system provided in an embodiment of the present invention includes: S101, using the Beidou receiver in the Beidou receiver data acquisition system, obtain Beidou observation data of four Beidou receiver antennas on the buoy; and receive data from the Beidou reference station on shore, perform differential positioning between the Beidou main antenna on the buoy and the Beidou reference station on shore, and obtain a differential positioning result of the buoy main antenna relative to the reference station; The Beidou receiver in the all-weather, real-time, high-precision Beidou receiver data acquisition system is used to obtain Beidou observation data from four Beidou receiver antennas on the buoy; the Beidou receiver data acquisition system includes a buoy, a Beidou receiver, a Beidou receiver antenna, a data acquisition module and a power module; Four BeiDou receivers are arranged on the buoy in a symmetrical cross pattern and fixed. The four BeiDou receivers are connected to four external BeiDou receiver antennas; The data acquisition module performs data storage and data transmission; The power module uses a combination of solar panels and batteries as the power supply system.

[0023] S102, after the real-time observation data of the Beidou buoy is preprocessed and the gross errors and detection cycle slips are eliminated, the dynamic baseline vector is solved with high precision using the dynamic difference mode to obtain the initial value of the baseline vector between the four Beidou receiver antennas; specifically, it includes: S1021, the collected Beidou observation data is subjected to a posteriori processing of gross errors through the method of “detection-identification-adjustment”; S1022: A more rigorous cycle slip detection is performed on Beidou observation data after gross errors are eliminated using the dual-frequency code phase combination method and the ionospheric residual method; S1023, using the dynamic differential mode to perform high-precision dynamic baseline vector solution to obtain the baseline vector value between the four Beidou receiver antennas; S1024 uses the integer ambiguity reduction correlation integer least squares estimation LAMBDA algorithm to effectively resolve the ambiguity and obtain an integer solution, which can greatly improve the accuracy of the baseline vector.

[0024] S103, based on the baseline network data of four Beidou receiver antennas acquired in real time, using baseline length priori constraints and dynamic unconstrained network adjustment solution, detect and weaken gross errors and closure errors in the initial value results of baseline vector solution; The four-antenna design has more redundant observations, which can ensure that low-cost Beidou receiver equipment provides stable and reliable GNSS positioning results, and adopts network adjustment to further improve the accuracy and reliability of the solution, and obtain high-precision baseline vector values ​​between Beidou antennas relative to the main antenna. Specifically include: S1031, dynamic baseline solution based on baseline length constraint; S1032, dynamic baseline solution based on dynamic unconstrained network adjustment solution.

[0025] S104, using the real-time baseline vector results between the four antennas calculated, through coordinate conversion, to obtain the real-time attitude angles of the current carrier in the heading, roll and pitch directions; The Beidou four-antenna method can quickly and accurately obtain the absolute attitude angle, avoiding the problem of large offsets of traditional inertial attitude equipment during long-term operation and the need for regular positioning, maintenance and correction, and effectively solving the maintenance problems of marine observation equipment. Specifically, it includes: S1041, relationship between baseline vector in carrier coordinate system and navigation coordinate system; ; In the formula, are the baseline vectors in the navigation coordinate system and the carrier coordinate system respectively, is the attitude transfer matrix from the carrier coordinate system to the navigation coordinate system; S1042, direct method to solve the approximate values ​​of attitude angles (heading angle, pitch angle and roll angle) , , ; S1043, performing attitude calculation using the least square method based on the relationship of the rotation transformation to obtain attitude information of the carrier; S105, after buoy attitude correction is performed based on the physical parameters of the buoy, a precise buoy geodetic height observation result is obtained; based on the real-time three-dimensional attitude angle information of the GNSS system, a real-time attitude correction value is provided for the ocean buoy observation carrier to ensure the vertical measurement of the ocean surface height by the equipment on the buoy carrier, correct the height error caused by the tilt of the buoy body due to the influence of wave surge, and eliminate the systematic offset error caused by the attitude angle correction based on the inertial device measurement; specifically including: S1051, based on the data of the BeiDou reference station on the shore, dynamically solves the baseline formed by the multi-antenna of the offshore buoy to obtain the instantaneous geodetic elevation of the phase center of the BeiDou main antenna of the buoy ; S1052: Perform attitude calculation based on the dynamic baseline vector between Beidou receiver antennas to obtain the tilt angle of the buoy , the roll angle on the buoy carrier is known and pitch angle , assuming there are unit vectors in the directions of roll angle, pitch angle and heading angle, the coordinate vectors of the unit vectors in the directions of roll angle and pitch angle in the carrier coordinate system are: ; ; In order to estimate the inclination angle of the buoy carrier, it is necessary to determine the angle between the normal line of the plane where the unit vectors of the roll angle and the pitch angle lie and the plumb line. With normal vector The relationship satisfies: ; The vector defining the direction of the plumb line is , then add a condition here, let the normal vector of The axis direction is positive and the value is 1; get the normal vector , the normal vector and The angle is the inclination angle of the buoy carrier , the expression is: ; In the formula, is the vector in the direction of the plumb line; S1053, based on the measurement results, multi-antenna Beidou sea level height The calibration formula of sea level height is expressed as: ; In the formula, is the instantaneous geodetic elevation of the phase center of the Beidou main antenna of the buoy, is the height from the phase center of the Beidou receiver antenna to the water surface.

[0026] It can be seen from the above embodiments that the present invention aims to obtain precise buoy geodetic elevation observation results after buoy attitude correction based on buoy physical parameters, reduce the impact of complex sea conditions on buoy height measurement results, and improve the applicability of ocean buoys in severe sea conditions.

[0027] Embodiment 2, as Figure 2 As shown, the ocean buoy observation carrier attitude correction system based on multi-antenna Beidou provided by the embodiment of the present invention includes: a Beidou receiver data acquisition system 1, a Beidou dynamic baseline precision processing module 2, and a buoy attitude precision estimation and correction module 3.

[0028] The Beidou receiver data acquisition system 1 is used to deploy Beidou receiver equipment and collect observation data to obtain high-quality observation data (Beidou observation data) as much as possible; The Beidou dynamic baseline precision processing module 2 adopts a dynamic differential mode to perform baseline vector solution of four Beidou receiver antennas; according to the baseline network data of the four Beidou receiver antennas acquired in real time, through baseline length prior constraints and dynamic unconstrained network adjustment solution, the gross error results in the baseline vector (Beidou baseline vector) are detected and weakened, and high-precision and high-reliability independent baseline vector results of the four Beidou receiver antennas are obtained; The buoy attitude precise estimation and correction module 3 obtains the current real-time attitude result by using the baseline vector calculated in real time; the buoy attitude result determined by the baseline vector is corrected by the initial attitude to eliminate the relative initial attitude error caused by the placement between the baseline network and the observation carrier platform. The precise buoy attitude result obtained by the baseline network is used to correct the elevation error caused by the attitude of the buoy, and obtain the precise ocean buoy observation result after attitude correction, which reduces the influence of complex sea conditions on the results of the buoy carrier observation platform and improves the applicability of the ocean buoy in severe sea conditions; Exemplarily, the Beidou receiver data acquisition system includes a buoy, a Beidou receiver, a Beidou receiver antenna, a data acquisition module and a power module; The bottom of the buoy is designed with an anchor chain attachment, and the buoy is placed in a designated sea area for observation through the anchor chain to ensure that the buoy does not drift over a large range.

[0029] The Beidou receiver is placed and fixed on the platform in the buoy working cabin, and connected to the four external Beidou receiver antennas through connecting wires. The four Beidou receiver antennas are arranged on the outer edge of the top platform of the buoy mast, showing a symmetrical cross distribution, and are fixed by metal connecting rods to ensure that the top is in an open and unobstructed environment.

[0030] The data acquisition module records the Beidou data observed by the four Beidou receiver antennas and sends the Beidou data to the processor for processing.

[0031] The power module adopts a combination of solar panels and batteries as a power supply system, and the battery power ensures that the equipment can work continuously for 2 weeks without solar energy.

[0032] The Beidou dynamic baseline precision processing module 2 includes using a dynamic differential mode to solve the baseline vectors of four Beidou receiver antennas; based on the baseline network data of the four Beidou receiver antennas acquired in real time, through baseline length prior constraints and dynamic unconstrained network adjustment solution, the gross error results in the baseline vector are detected and weakened, and high-precision and high-reliability independent baseline vector results of the four Beidou receiver antennas are obtained.

[0033] The collected observation data are processed for gross errors through the method of “detection-identification-adjustment”.

[0034] The dual-frequency code combination method and ionospheric residual method are added to the observation data that have been free of gross errors to perform more rigorous cycle slip detection.

[0035] The dynamic differential mode is used to perform high-precision dynamic baseline vector solution to obtain the baseline vector value between the four Beidou receiver antennas. The dynamic differential mode includes: using two Beidou receiver antennas installed on a moving carrier for differential processing, in which the coordinates of the Beidou receiver antenna as a reference station are no longer set to a fixed value, but the result of real-time dynamic positioning is used. The Beidou receiver as a mobile station performs differential processing with the reference station to solve the baseline vector of the mobile station relative to the reference station.

[0036] Specifically, in the double-difference observation model, at the same time, two receivers perform differential observations of the same satellite to eliminate the common errors between the receivers. The same receiver performs differential observations of two different satellites at two different times to eliminate the common errors between the satellites. The constructed satellite station double-difference model is: ; ; In the formula, is the double-difference pseudo-range observation value of the satellite station at time 𝑡, in meters, is the double-difference geometric distance of the star station at time 𝑡, in meters, is the double-difference ionospheric error of the satellite station at time 𝑡, is the double-difference tropospheric error of the satellite station at time 𝑡, is the other error term of the double difference of the satellite station at time 𝑡, in meters, is the double-difference carrier phase observation value of the satellite station at time 𝑡, in weeks, Initial epoch The station double difference of the weekly ambiguity determined at time, in weeks, The rover and non-reference satellite numbers are are the reference station and reference satellite numbers, respectively. is the original pseudorange observation from the satellite to the receiver, in meters; is the spatial geometric distance from the satellite to the receiver, in meters; are the ionospheric and tropospheric errors, respectively. For other errors, is the integer ambiguity value in the carrier phase observation value, in weeks; is the wavelength of the frequency.

[0037] Exemplarily, carrier phase observations are used to resolve ambiguities, and a LAMBDA algorithm is used to reduce the correlation of integers by converting the variance-covariance matrix of floating-point ambiguity solutions to achieve integer reduction in correlation, weaken the correlation between floating-point ambiguity solutions, reduce the ambiguity search space, and achieve rapid ambiguity fixation.

[0038] Exemplarily, the method of detecting and weakening gross error results in the Beidou baseline vector by using baseline length prior constraints and dynamic unconstrained network adjustment solution based on the baseline network data of the four Beidou receiver antennas acquired in real time, and obtaining high-precision and high-reliability independent baseline vector results of the four Beidou receiver antennas includes: (1) Dynamic baseline solution based on baseline length constraint.

[0039] Added pseudo-measurement equation measurement value , measurement equation , observation matrix , the covariance of the measurement noise They are: ; ; ; ; In the formula, is the baseline length, is the position of the rover, is the signal receiving time, is the location of the base station, is the error in the baseline length, represents transpose; (2) Dynamic baseline solution based on dynamic unconstrained network adjustment.

[0040] According to the error equation, the reference equation and the equation-covariance matrix, the adjustment is performed according to the least squares principle to obtain the adjusted result: ; In the formula, is the parameter correction number after adjustment, is the coefficient matrix, For transposition, is the covariance matrix of the observations The inverse matrix of is the coefficient matrix of the benchmark equation, is the error vector of the observed value; Coordinates of each point after adjustment It is expressed as: ; In the formula, is the initial coordinate value before adjustment; The unit weighted mean error after adjustment is: ; In the formula, is the number of baselines that make up the Beidou network. is the total number of measuring stations involved in the adjustment, is the unit weight error, is the correction vector.

[0041] Exemplarily, in the buoy attitude precise estimation and correction module 3, the current real-time attitude result is obtained by using the baseline vector calculated in real time; the buoy attitude result determined by the baseline vector is corrected by the initial attitude to eliminate the relative initial attitude error caused by the placement between the baseline network and the observation carrier platform. The precise buoy attitude obtained by the baseline network is used to correct the elevation error caused by the buoy attitude, and the precise ocean buoy observation result after attitude correction is obtained, which specifically includes: (1) Based on the data from the onshore Beidou reference station, the baseline is dynamically calculated with the multi-antenna of the offshore buoy to obtain the instantaneous geodetic elevation of the phase center of the Beidou main antenna of the buoy. ; (2) Perform attitude calculation based on the dynamic baseline vector between Beidou receiver antennas to estimate the inclination angle of the buoy , the roll angle on the buoy carrier is known and pitch angle , assuming there are unit vectors in the directions of roll angle, pitch angle and heading angle, the coordinate vectors of the unit vectors in the directions of roll angle and pitch angle in the carrier coordinate system are: ; ; In order to estimate the inclination angle of the buoy carrier, it is necessary to determine the angle between the normal line of the plane where the unit vectors of the roll angle and the pitch angle lie and the plumb line. With normal vector The relationship satisfies: ; The vector defining the direction of the plumb line is , then add a condition here, let the normal vector of The axis direction is positive and the value is 1; get the normal vector , the normal vector and The angle is the inclination angle of the buoy carrier , the expression is: ; (3) Based on the measurement results, multi-antenna Beidou sea surface height The calibration formula of sea level height is expressed as: ; In the formula, is the instantaneous geodetic elevation of the phase center of the Beidou main antenna of the buoy, is the height from the phase center of the Beidou receiver antenna to the water surface.

[0042] Example 3, exemplary, as another embodiment of the present invention, as Figure 3 As shown, the attitude correction method of the ocean buoy observation carrier based on multi-antenna Beidou includes: S1 uses an all-weather, real-time, high-precision BeiDou receiver to obtain observation data from four BeiDou receiver antennas on the buoy. The BeiDou receiver antennas are symmetrically cross-distributed to obtain the maximum baseline length on the narrow buoy platform as much as possible.

[0043] In step S1, a BeiDou receiver data acquisition system is assembled, including a buoy, a BeiDou receiver, four BeiDou receiver antennas, a data acquisition module and a power module, to complete the assembly of the entire system.

[0044] S11, assemble the Beidou receiver data acquisition system: An anchor chain attachment is designed at the bottom of the buoy body, and the anchor chain is used to place the buoy in the designated sea area for observation to ensure that the buoy does not drift over a large area. The Beidou receiver is placed and fixed on the platform inside the buoy working cabin, and is connected to the four external Beidou receiver antennas through connecting wires. The four Beidou receiver antennas are arranged on the outer edge of the top platform of the buoy mast in a symmetrical cross distribution and are fixed by metal connecting rods to ensure that the top is in an open and unobstructed environment. The Beidou receiver antenna uses a choke antenna, and the equipment data is connected to the data acquisition module. Figure 4 The schematic diagram shows four receiver antennas installed on a buoy in a symmetrical cross shape; S12, the data acquisition module includes: a data storage solution and a data transmission solution.

[0045] Data storage solution: TF card is used as the storage medium. TF card has the advantages of low power consumption, small size, easy replacement, and the writing speed fully meets the storage needs.

[0046] Data transmission solution: It adopts wireless transmission based on 4G module, and reserves RJ45 network port and USART serial port. The network port provided can be connected to wired network, wireless router and other devices, and the USART serial port can be used for data debugging and external high-power radio and other equipment.

[0047] Use Beidou receivers to collect original observation data of Beidou satellites such as pseudorange, carrier phase observation values, Doppler frequency shift and other basic observation quantities, store the collected observation data, and complete data collection.

[0048] S13, power module: provides stable and continuous power supply. The power supply module adopts 9-36V wide voltage design and adopts solar panel and battery combination power supply mode to provide a single working voltage for the data acquisition system. The solar panel is installed on the side of the buoy platform. The side of the buoy is equipped with a sealed battery compartment, which is equipped with maintenance-free batteries. The battery power ensures that the equipment can work continuously for 2 weeks without solar energy.

[0049] S2, after data preprocessing and elimination of gross errors and detection cycle slips, the Beidou observation data is subjected to high-precision dynamic baseline vector solution using the dynamic differential mode to obtain the baseline vector values ​​between the four Beidou receiver antennas.

[0050] S21, under complex ocean conditions, Beidou observations usually inevitably contain gross errors. The data detection method is used to perform a posteriori processing on the gross errors, which is specifically divided into the following three steps: S211, detection: detect the data through statistics, calculate the redundant number of observations and their variance matrix. Use chi-square test to test the hypothesis and set the significance level. If the test result is significant, it means that there are abnormal data in the observations, the alternative hypothesis is established, and further identification steps are entered; on the contrary, if the test result is not significant, it means that there is no abnormality in the data, the original hypothesis is established, and the detection process is terminated.

[0051] S212, identification: construct a test statistic by standardizing the residual, and calculate based on the residual and covariance matrix of the observed data. The test quantity follows the standard normal distribution. If the test result exceeds the critical value of the significance level, it means that the abnormal data is most likely to appear on a certain observation. At this time, after removing the observation, re-adjustment is performed, and the statistics of the overall test are used to determine whether there are still abnormal data. If an abnormality is found, continue the identification step until the global test is passed.

[0052] S213 Adjustment: Finally, the least squares estimation is re-performed using the remaining observations to obtain a reliable result, and the result is output; S22, the satellite signal is blocked by some obstacles and cannot reach the receiver, or the satellite signal is temporarily unlocked due to external interference or the bad dynamic conditions of the receiver, which will cause cycle slip problems. The present invention adopts dual-frequency code combination method and ionospheric residual method to perform more rigorous cycle slip detection.

[0053] S23, uses the dynamic differential mode to perform high-precision dynamic baseline vector solution to obtain the baseline vector value between the four Beidou receiver antennas. Dynamic differential mode: Use two antennas installed on a moving carrier for differential processing, and the coordinates of the base station are no longer set to a fixed value. The mobile station continuously receives satellite signals and receives real-time satellite observation data from the mobile base station. The baseline vector from the mobile station to the mobile base station is obtained through solution; including: S231, Beidou dynamic differential positioning adopts a double difference observation model. At the same time, two receivers perform differential observations of the same satellite to eliminate the common errors between the receivers. The same receiver performs differential observations of two different satellites at two different times to eliminate the common errors between the satellites.

[0054] S232, constructing the double-difference model of the star station; S24 uses the least squares ambiguity reduction and association adjustment (LAMBDA) algorithm to achieve fast ambiguity fixation.

[0055] S241, without external constraints, directly used the least squares method to solve the Beidou double difference observations obtained from multiple baselines to obtain the parameter solution and And the cofactor matrix , the Beidou double difference observation equation obtained from multiple baselines is: ; ; In the formula, is the observation equation, is the unknown double difference parameter of the baseline, , for The double difference parameters of the baseline are unknown; is the unknown parameter of the baseline length, , For the The unknown baseline length parameter of the baseline; for The unknown double difference parameter matrix of the baseline, for Contains The matrix of baselines, is the covariance of the observation vector, is the covariance matrix of the observations; , for Code and phase linearized observation vectors of the baseline; for The ambiguity coefficient matrix, for The mapping matrix, is the cofactor matrix between baselines, is the cofactor matrix of pseudorange and phase, for product; S242, construct the optimal problem for fuzzy search: ; ; In the formula, is the optimal integer ambiguity solution, is the dimension of the search space, is the vectorized operation of the matrix, is the floating point solution for the ambiguity, is the weighted Euclidean norm, which measures and The weighted distance between is a constraint set, representing the set of all possible ambiguity solutions, is a given constant used to define the size of the search space; By search criteria Under the constraint of The nearest ambiguity vector; since the search ellipsoid at this time It tends to be long and strip-shaped, with a larger search radius and more prepared ambiguity value data, which reduces the efficiency of ambiguity search.

[0056] S243, LAMBDA algorithm will be the initial and ambiguity float solution Gaussian orthogonal transformation is performed to reduce the internal correlation of the floating-point solution ambiguity, and a series of correlation reduction processes are performed on the floating-point solution to finally obtain an integer solution.

[0057] ; ; In the formula, is the integer ambiguity vector obtained by transformation, is the orthogonal transformation matrix The transpose of is the orthogonal transformation matrix The transpose of is the integer ambiguity vector The covariance matrix of is an orthogonal integer transformation matrix with a modulus of 1, and after the transformation The off-diagonal elements of are less than or equal to 0.5; S244, test and back substitution of integer ambiguity: adopt the significant ratio test, that is, set a threshold value, called Value, test the ratio of the second smallest value to the smallest value , if the test value If it is greater than a certain threshold, it means that the fuzzy search is correct.

[0058] ; In the formula, is the second minimum value of the objective function, is the minimum value of the objective function, the optimal integer ambiguity solution The objective function value of It is a pre-set threshold, and its value range is generally 2 to 3; It is believed that The corresponding integer ambiguity value is the correct ambiguity combination.

[0059] S25, baseline solution is completed, and the baseline solution result outputs an independent baseline vector and its complete variance-covariance matrix.

[0060] Specifically, it can be expressed as: ; In the formula, , , They represent the variance of the baseline vector in the three-axis directions, and the remaining elements represent the covariance.

[0061] S3, based on the baseline network data of the four Beidou receiver antennas acquired in real time, detects and weakens the gross error results in the Beidou baseline vector through baseline length prior constraints and dynamic unconstrained network adjustment, and obtains high-precision and high-reliability independent baseline vector results of the four Beidou receiver antennas. Specifically including: S31, dynamic baseline solution based on baseline length constraint.

[0062] When constructing Beidou's observation equations, the baseline length constraint is added as a pseudo-measurement equation to improve the accuracy of the floating-point solution when the observation environment is poor.

[0063] Added pseudo-measurement equation measurement value , measurement equation , observation matrix , the covariance of the measurement noise They are: ; ; ; ; In the formula, represents the baseline length, Indicates the location of the base station, represents the location of the rover, Indicates the signal receiving time, Indicates the error in the baseline length.

[0064] S32, dynamic baseline solution based on dynamic unconstrained network adjustment solution.

[0065] S321, error equation of Beidou network adjustment.

[0066] The observation values ​​used in the Beidou network 3D unconstrained adjustment are all baseline vectors, that is, the coordinate difference from the start point to the end point of the baseline. Therefore, for each baseline vector, the following error equation can be listed: ; In the formula, and Respectively , The coordinates of the point, The baseline solution is obtained , The baseline vector formed by the points, It represents the difference between the baseline vector obtained by the difference of point coordinates and the baseline vector obtained by baseline solution. , Indicates the correction value.

[0067] S322, the present invention adopts the rank-deficient free network benchmark method to construct the Beidou network benchmark equation.

[0068] The rank-deficient free network datum is based on the centroid of the entire network, and the coordinates of all stations are corrected according to the adjustment to obtain the corresponding correction values. Then the datum equation can be written as: ; Where: ; S323, observation value weight matrix of Beidou network adjustment.

[0069] In the three-dimensional unconstrained adjustment of Beidou Network, the baseline vector observation value weight matrix is ​​usually determined by the variance-covariance matrix of each baseline vector obtained during baseline solution. The variance-covariance matrix can be obtained during baseline solution and can be specifically expressed as: ; In the formula, , , Respectively represent the variance of the baseline vector in the three-axis direction, and the remaining elements represent the covariance. After inverting the variance covariance matrix, the weight matrix of the observation value can be obtained ,Right now: ; Using the covariance matrix and weight matrix for network adjustment can effectively integrate the observations of all stations, improve measurement accuracy and reduce errors, while also improving the efficiency and automation of data processing.

[0070] S324, Beidou network least squares adjustment.

[0071] According to the above error equation, benchmark equation and variance-covariance matrix, the adjustment is performed according to the least squares principle to obtain the adjusted result: ; At this time, the coordinates of each point after adjustment It can be expressed as: ; Unit weighted mean error after adjustment: ; In the above formula, is the number of baselines that make up the Beidou network. is the total number of measuring stations involved in the adjustment.

[0072] At this point, the detection and reduction of gross errors in the Beidou baseline vector have been completed through baseline length prior constraints and dynamic unconstrained network adjustment solutions, and high-precision and high-reliability independent baseline vector results for the four Beidou receiver antennas have been obtained.

[0073] S4, using the baseline vector calculated in real time to obtain the current real-time posture result; S41, the relationship between the position vector of the same baseline in the carrier coordinate system and the position vector in the navigation coordinate system reflects the relationship of the rotation transformation between the carrier coordinate system and the navigation coordinate system. Through the relationship of the rotation transformation, the attitude is solved using the least squares method to obtain the attitude information of the carrier.

[0074] The heading angle, pitch angle and roll angle are respectively , , It is represented by the angle of rotation around the Z axis, X axis and Y axis. The rotation is positive if it satisfies the right-hand rule, and negative if it does not. The three rotations are represented by the attitude matrix The method can be expressed as: ; Then the attitude angle can be expressed as: , , ; S42, establishment of coordinate system.

[0075] According to the principle of geometry, three non-collinear points can determine a plane. There are four Beidou receiver antennas , , , , the four antennas are distributed in a symmetrical cross. point to Denoted as vector , point to Denoted as vector , in the carrier coordinate system, the baseline vector coincides with the Y axis of the carrier coordinate system, It is located in the plane formed by the X-axis and the Y-axis. The Z-axis is perpendicular to the plane formed by the XY axis and points to the zenith direction. The XYZ axes form a right-handed coordinate system.

[0076] S43, approximate values ​​of attitude angles (heading, pitch and roll) based on direct method , , ; Through baseline solution, two baseline vectors are obtained respectively and Values ​​in the Earth-centered Earth-fixed coordinate system (ECEF) , ,by Establish the station center coordinate system (ENU) as the origin (coincides with the local navigation coordinate system) and calculate , The coordinates in the station center coordinate system (ENU) are recorded as , .

[0077] The baseline vector in the ECEF coordinate system obtained by the baseline length prior constraint and dynamic unconstrained network adjustment in S3 To convert to the local coordinate system, the following formula can be used: ; In the formula, is the baseline vector in the station center coordinate system, is the latitude of the station center, It is the longitude of the center of the station.

[0078] Get the baseline vector in the station center coordinate system (ENU) and , available Calculate the heading angle and pitch angle, where the heading angle and pitch angle Respectively expressed as: ; ; For the baseline vector , the relationship between the carrier coordinate system and the station center coordinate system can be expressed as: ; Use the above formula to find the heading angle and pitch angle After finishing, we can get: ; In the formula, , , is an abbreviation for the baseline vector after two rotations. .

[0079] After finishing, we can get: ; Expanding the formula, we can get the roll angle: ; The approximate value of the attitude angle solved is marked as , , .

[0080] S44, least square method based on multiple antennas to solve attitude angles (heading angle, pitch angle and roll angle) The relationship between any baseline vector in the carrier coordinate system and the navigation coordinate system can be expressed as: ; The baseline vector in the carrier coordinate system is known during installation. The baseline vector in the navigation coordinate system is obtained by solving the baseline vector. Solving the attitude is to solve the transformation matrix. The three unknowns contained in , , .

[0081] set up The antenna is the main antenna, which is the origin of the carrier coordinate system. The baseline vector from the main antenna to other antennas in the carrier coordinate system is ,Right now: .

[0082] Will , , And bring in After rearrangement, the error equation can be expressed as: ; Linearize the above equation and further simplify it to get: ; ; In the formula, is the observed value The covariance matrix of is, and the other symbols are represented as follows: ; ; ; ; ; Then the estimated attitude angle is: ; The covariance matrix is: ; Through multiple iterations of the least squares method, until the correction value The iteration is completed when the value of is less than the threshold. , Pitch angle and roll angle ).

[0083] S45, mast tilt angle of determination.

[0084] Buoy attitude (heading angle , Pitch angle and roll angle ) changes, the vertical height of the buoy mast will also change. It is related to the horizontal position or orientation of an object, but it does not directly affect the vertical height. and roll angle It will affect the height of the mast. The two angles are projected by vectors to get the mast inclination angle. .

[0085] S5, after buoy attitude correction based on buoy physical parameters, obtains precise buoy geodetic height observation results, reduces the impact of complex sea conditions on buoy height measurement results, and improves the applicability of ocean buoys in severe sea conditions.

[0086] S51, based on the data of the Beidou reference station on the shore, dynamically solves the baseline formed by the multi-antenna of the offshore buoy to obtain the instantaneous geodetic elevation of the phase center of the Beidou main antenna of the buoy ; S52, multi-antenna Beidou buoy attitude solution, estimate the mast tilt angle of the buoy .

[0087] In the above step S45, the roll angle on the buoy carrier is known. and pitch angle , assuming there are unit vectors in the directions of roll angle, pitch angle and heading angle, the coordinate vectors of the unit vectors in the directions of roll angle and pitch angle in the carrier coordinate system are ; ; The carrier coordinate system is as follows: Figure 5 shown.

[0088] In order to estimate the inclination angle of the buoy carrier, it is necessary to determine the angle between the normal line of the plane where the unit vectors of the roll angle and the pitch angle lie and the plumb line. With normal vector The relationship satisfies: ; The vector defining the direction of the plumb line is , then add the condition here, let The Z-axis direction is positive and its value is 1. Therefore, the normal vector is obtained .

[0089] Then the normal vector and The angle is the inclination angle of the buoy carrier ,Right now ; S53, based on the above measurement results, the multi-antenna buoy sea surface height The calibration formula of sea level height is expressed as: ; In the formula, is the height from the phase center of the Beidou receiver antenna to the water surface.

[0090] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for correcting the attitude of an ocean buoy observation carrier based on a multi-antenna Beidou, characterized in that: The method comprises the following steps: S101, using the Beidou receiver in the Beidou receiver data acquisition system, obtain Beidou observation data of four Beidou receiver antennas on the buoy; and receive data from the Beidou reference station on shore, perform differential positioning between the Beidou main antenna on the buoy and the Beidou reference station on shore, and obtain a differential positioning result of the buoy main antenna relative to the reference station; S102, the real-time Beidou observation data of the buoy is preprocessed to remove gross errors and detection cycle slips, and then a high-precision dynamic baseline vector solution is performed using a dynamic difference mode to obtain the initial value of the baseline vector between the four Beidou receiver antennas; S103, based on the baseline network data of four Beidou receiver antennas acquired in real time, using baseline length priori constraints and dynamic unconstrained network adjustment solution, detect and weaken gross errors and closure errors in the initial value results of baseline vector solution; S104, using the real-time baseline vector results between the four antennas calculated, through coordinate conversion, to obtain the real-time attitude angles of the current carrier in the heading, roll and pitch directions; S105, after buoy attitude correction based on the physical parameters of the buoy, obtain precise buoy geodetic height observation results; based on the real-time three-dimensional attitude angle information of the GNSS system, provide real-time attitude correction values ​​for the ocean buoy observation carrier, ensure the vertical measurement of the ocean surface height by the equipment on the buoy carrier, correct the height error caused by the tilt of the buoy body due to the influence of wave surges, and eliminate the systematic offset error caused by the attitude angle correction based on inertial equipment measurement.

2. The method for correcting the attitude of an ocean buoy observation carrier based on multi-antenna Beidou according to claim 1 is characterized in that: In step S101, the Beidou receiver data acquisition system includes: a buoy, a Beidou receiver, a Beidou receiver antenna, a data acquisition module and a power module; Four BeiDou receivers are deployed on the buoy in a symmetrical cross arrangement. The four BeiDou receivers are connected to four external BeiDou receiver antennas. The data acquisition module performs data storage and data transmission; The power module uses a combination of solar panels and batteries as the power supply system.

3. The method for correcting the attitude of an ocean buoy observation carrier based on multi-antenna Beidou according to claim 1 is characterized in that: In step S102, the initial value of the baseline vector between the four Beidou receiver antennas is obtained, including: S1021, for the collected Beidou observation data, the gross errors are processed a posteriori by means of detection, identification and adjustment; S1022: for the Beidou observation data that has been removed from the rough inspection, the dual-frequency code phase combination method and the ionospheric residual method are used to detect cycle slips; S1023, using the dynamic differential mode to perform high-precision dynamic baseline vector solution to obtain the baseline vector value between the four Beidou receiver antennas; S1024, using the integer ambiguity reduction correlation integer least squares estimation LAMBDA algorithm to resolve the ambiguity and obtain an integer solution.

4. The method for correcting the attitude of an ocean buoy observation carrier based on multi-antenna Beidou according to claim 3 is characterized in that: In step S1021, the gross errors are processed a posteriori by means of detection, identification, and adjustment, including: In the detection phase, the data is tested through statistics, the redundant number of observations and the variance matrix are calculated, and the chi-square test is used to determine whether there are abnormal data; if the test is significant, the identification step is entered; if not significant, the detection is stopped; In the identification stage, the test statistic is constructed by standardizing the residual. The test value exceeding the significance level indicates that a certain observation value is abnormal data. After removing the value, re-adjustment is performed and the overall test is performed. If there is still an abnormality, continue to identify until the global test passes. The adjustment phase uses the remaining observations to perform least squares estimation, and finally obtains the result and outputs it.

5. The method for correcting the attitude of an ocean buoy observation carrier based on multi-antenna Beidou according to claim 3 is characterized in that: In step S1023, the dynamic differential mode includes: using two Beidou receiver antennas installed on the moving carrier to perform differential processing, the coordinates of the Beidou receiver antenna as the reference station are not set to fixed values, and the results of real-time dynamic positioning are used; the Beidou receiver as the mobile station performs differential processing with the reference station to solve and obtain the baseline vector of the mobile station relative to the reference station; The dynamic differential mode is used to perform high-precision dynamic baseline vector solution to obtain the baseline vector between the four Beidou receiver antennas; in the double-difference observation model, at the same time, the two receivers perform differential observations of the same satellite to eliminate the common errors between the receivers; the same receiver performs differential observations of two different satellites at two different times to eliminate the common errors between the satellites; the constructed satellite station double-difference model is: ； ； In the formula, is the double-difference pseudo-range observation value of the satellite station at time 𝑡, in meters, is the double-difference geometric distance of the star station at time 𝑡, in meters, is the double-difference ionospheric error of the satellite station at time 𝑡, is the double-difference tropospheric error of the satellite station at time 𝑡, is the other error term of the double difference of the satellite station at time 𝑡, in meters, is the double-difference carrier phase observation value of the satellite station at time 𝑡, in weeks, Initial epoch The station double difference of the weekly ambiguity determined at time, in weeks, The rover and non-reference satellite numbers are are the reference station and reference satellite numbers, respectively. is the original pseudorange observation from the satellite to the receiver, in meters; is the spatial geometric distance from the satellite to the receiver, in meters; are the ionospheric and tropospheric errors, respectively. For other errors, is the integer ambiguity value in the carrier phase observation value, in weeks; is the wavelength of the frequency.

6. The method for correcting the attitude of an ocean buoy observation carrier based on multi-antenna Beidou according to claim 3 is characterized in that: In step S1024, the integer ambiguity reduction correlation integer least squares estimation LAMBDA algorithm is used to resolve the ambiguity and obtain an integer solution, including: converting the variance covariance matrix of the floating-point solution ambiguity value to achieve integer reduction correlation, weakening the correlation between the floating-point solution ambiguities, reducing the ambiguity search space, and achieving rapid ambiguity fixation; the specific steps are: (a) Without external constraints, the parameter solution is obtained by using the least squares method to solve the Beidou double-difference observations obtained from multiple baselines through double-difference observation data. and and the cofactor matrix , the Beidou double difference observation equation obtained from multiple baselines is: ； ； In the formula, is the observation equation, is the unknown double difference parameter of the baseline, , for The double difference parameters of the baseline are unknown; is the unknown parameter of the baseline length, , For the The unknown baseline length parameter of the baseline; for The unknown double difference parameter matrix of the baseline, for Contains The matrix of baselines, is the covariance of the observation vector, is the covariance matrix of the observations; , for Code and phase linearized observation vectors of the baseline; for The ambiguity coefficient matrix, for The mapping matrix, is the cofactor matrix between baselines, is the cofactor matrix of pseudorange and phase, for product; (b) Construct the optimal problem for fuzzy search, expressed as: ； ； In the formula, is the optimal integer ambiguity solution, is the dimension of the search space, is the vectorized operation of the matrix, is the floating point solution for the ambiguity, is the weighted Euclidean norm, which measures and The weighted distance between is a constraint set, representing the set of all possible ambiguity solutions, is a given constant used to define the size of the search space; By search criteria Under the constraint of The nearest blur vector; (c) The LAMBDA algorithm converts the initial and ambiguity float solution Perform Gaussian orthogonal transformation to reduce the internal correlation of the floating-point solution ambiguity, perform correlation reduction processing on the floating-point solution, and finally obtain an integer solution; ; ; In the formula, is the integer ambiguity vector obtained by transformation, is the orthogonal transformation matrix The transpose of is the orthogonal transformation matrix The transpose of is the integer ambiguity vector The covariance matrix of is an orthogonal integer transformation matrix with a modulus of 1, and after the transformation The off-diagonal elements of are less than or equal to 0.5; (d) Test and back-substitution of the integer ambiguity, using the significance ratio test and setting the threshold Value, test the ratio of the second smallest value to the smallest value , if the test value If it is greater than the threshold, the fuzzy search is correct; ； In the formula, is the second minimum value of the objective function, is the minimum value of the objective function, the optimal integer ambiguity solution The objective function value of It is a pre-set threshold, and its value range is generally 2 to 3; It is believed that The corresponding integer ambiguity value is the correct ambiguity combination.

7. The method for correcting the attitude of an ocean buoy observation carrier based on multi-antenna Beidou according to claim 1 is characterized in that: In step S103, based on the four Beidou receiver antenna baseline network data acquired in real time, the baseline length priori constraint and the dynamic unconstrained network adjustment solution are used to detect and weaken the gross errors and closure errors in the initial value results of the baseline vector solution, and obtain the four Beidou receiver antenna independent baseline vector results with high precision and high reliability; specifically, it includes: S1031, dynamic baseline solution based on baseline length constraint; Added pseudo-measurement equation measurement value , measurement equation , observation matrix , the covariance of the measurement noise They are: ； ； ； ； In the formula, is the baseline length, is the position of the rover, is the signal receiving time, is the location of the base station, is the error in the baseline length, represents transpose; S1032, dynamic baseline solution based on dynamic unconstrained network adjustment solution; According to the error equation, the reference equation and the equation-covariance matrix, the adjustment is performed according to the least squares principle to obtain the adjusted result: ； In the formula, is the parameter correction number after adjustment, is the coefficient matrix, For transposition, is the covariance matrix of the observations The inverse matrix of is the coefficient matrix of the benchmark equation, is the error vector of the observed value; Coordinates of each point after adjustment It is expressed as: ； In the formula, is the initial coordinate value before adjustment; The unit weighted mean error after adjustment is: ； In the formula, is the number of baselines that make up the Beidou network. is the total number of measuring stations involved in the adjustment, is the unit weight error, is the correction vector.

8. The method for correcting the attitude of an ocean buoy observation carrier based on multi-antenna Beidou according to claim 1, characterized in that: In step S104, the real-time baseline vector results between antennas obtained by solving the four antennas are used to obtain the real-time attitude angles of the current carrier in the heading, roll and pitch directions through coordinate conversion; including: S1041, relationship between baseline vector in carrier coordinate system and navigation coordinate system; ； In the formula, are the baseline vectors in the navigation coordinate system and the carrier coordinate system respectively, is the attitude transfer matrix from the carrier coordinate system to the navigation coordinate system; S1042, direct method to solve the approximate values ​​of heading angle, pitch angle and roll angle , , ; S1043, using the relationship of rotation transformation, the least square method is used to perform posture calculation to obtain the posture information of the carrier.

9. The method for correcting the attitude of an ocean buoy observation carrier based on multi-antenna Beidou according to claim 1, characterized in that: In step S105, after the buoy attitude is corrected based on the buoy physical parameters, a precise buoy geodetic height observation result is obtained, including: S1051, based on the data of the BeiDou reference station on the shore, dynamically solves the baseline formed by the multi-antenna of the offshore buoy to obtain the instantaneous geodetic elevation of the phase center of the BeiDou main antenna of the buoy ; S1052: Perform attitude calculation based on the dynamic baseline vector between Beidou receiver antennas to obtain the tilt angle of the buoy , the roll angle on the buoy carrier is known and pitch angle , there are unit vectors in the directions of roll angle, pitch angle and heading angle, then the coordinate vectors of the unit vectors in the directions of roll angle and pitch angle in the carrier coordinate system are: ； ； In order to estimate the inclination angle of the buoy carrier, determine the angle between the normal line of the plane where the unit vectors of the roll angle and the pitch angle are located and the plumb line, then the direction vector With normal vector The relationship satisfies: ； The vector defining the direction of the plumb line is , then add a condition here, let the normal vector of The axis direction is positive and the value is 1; get the normal vector , the normal vector and The angle is the inclination angle of the buoy carrier , the expression is: ； In the formula, is the vector in the direction of the plumb line; S1053, based on the measurement results, multi-antenna Beidou sea level height The calibration formula of sea level height is expressed as: ； In the formula, is the instantaneous geodetic elevation of the phase center of the Beidou main antenna of the buoy, is the height from the phase center of the Beidou receiver antenna to the water surface.

10. A multi-antenna Beidou-based ocean buoy observation carrier attitude correction system, characterized in that: The system implements the method for correcting the attitude of an ocean buoy observation carrier based on multi-antenna Beidou as described in any one of claims 1 to 9, and the system comprises: The Beidou receiver data acquisition system (1) is used to deploy Beidou receiver equipment and collect observation data to obtain observation data; and receive data from a Beidou reference station on shore, perform differential positioning between the Beidou main antenna on the buoy and the Beidou reference station on shore, and obtain a differential positioning result of the buoy main antenna relative to the reference station; The Beidou dynamic baseline precision processing module (2) uses a dynamic differential mode to solve the baseline vectors of the four Beidou receiver antennas; based on the baseline network data of the four Beidou receiver antennas acquired in real time, the module detects and weakens the gross error results in the baseline vectors through baseline length prior constraints and dynamic unconstrained network adjustment and solves, thereby obtaining high-precision and high-reliability independent baseline vector results of the four Beidou receiver antennas; The buoy attitude precise estimation and correction module (3) obtains the current real-time attitude result by using the baseline vector calculated in real time; the buoy attitude result determined by the baseline vector is corrected by the initial attitude to eliminate the relative initial attitude error caused by the placement between the baseline network and the observation carrier platform; the precise buoy attitude result obtained by the baseline network is used to correct the elevation error caused by the buoy attitude, and obtain the precise ocean buoy observation result after attitude correction.

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