Real-time dam deformation monitoring method and system based on GNSS

Abstract

The present invention discloses a real-time dam deformation monitoring method based on GNSS satellites. The method mainly comprises: receiving real-time satellite data uploaded by GNSS reference stations and GNSS monitoring stations, parsing to obtain satellite observation data of each monitoring station; processing the satellite observation data using a static baseline solution mode, and obtaining the static three-dimensional coordinates of each monitoring station through adjustment calculation; calculating the real-time three-dimensional coordinates of each monitoring station using an RTK real-time algorithm, and then subtracting them from the static three-dimensional coordinates to obtain the real-time deformation of each monitoring station; establishing a station-centered coordinate system, and then converting the real-time deformation into a three-dimensional deformation in the station-centered coordinate system; constructing a dam coordinate system, calculating the rotation angle between the dam coordinate system and the station-centered coordinate system; and converting the three-dimensional deformation of each monitoring station in the station-centered coordinate system into a three-dimensional deformation in the dam body coordinate system. The method can intuitively display the deformation magnitude of the dam body in each direction in the dam body coordinate system.

Description

Technical Field

[0001] The present invention belongs to the technical field of building monitoring based on satellite positioning and navigation technology, and in particular relates to a real-time dam deformation monitoring method and system based on GNSS. Background Art

[0002] GNSS (Global Navigation Satellite System) has the advantages of all-weather operation, high positioning accuracy, and no accumulation of errors over time, making it widely used in deformation monitoring. With the known coordinates of the base station, RTK technology can be used to obtain the three-dimensional coordinates of each monitoring station in real time. By subtracting the real-time three-dimensional coordinates from the initial three-dimensional coordinates of the monitoring station, the three-dimensional coordinate deformation results of the monitoring station can be obtained in real time. The dam coordinate system is based on the phase center of each monitoring station antenna as the origin. The X-axis is positive along the downstream direction of the water flow, the Y-axis is perpendicular to the X-axis and forms a right-handed coordinate system with the X-axis, and the Z-axis is perpendicular to the plane formed by the X and Y axes and is positive pointing to the sky. Through the dam coordinate system, administrators can obtain the deformation results of the dam along the dam direction and perpendicular to the dam direction, which can more intuitively judge the health status of the dam and provide early warning. However, in the existing technology, a station center coordinate system is usually established for each monitoring station with each monitoring station as the center. The deformation results of the monitoring station in the station center coordinate system can be obtained in real time, but the deformation results in the station center coordinate system cannot be intuitively displayed in the dam body coordinate system. The deformation size in each direction is not conducive to the dam management personnel's analysis of the health status of the dam body. Summary of the Invention

[0003] To solve the above problems, the present invention discloses a real-time dam deformation monitoring method and system based on GNSS, which can convert the calculated three-dimensional coordinate deformation results into deformation results in the dam body coordinate system, thereby intuitively displaying the deformation size of the dam body in each direction in the dam body coordinate system.

[0004] To achieve the above-mentioned purpose, the present invention discloses a real-time dam deformation monitoring method based on GNSS satellites, which mainly includes the following steps:

[0005] Step 1: Receive real-time satellite data uploaded by the GNSS reference station and the GNSS monitoring station, and parse the real-time satellite data to obtain satellite observation data of each monitoring station;

[0006] Step 2: Process the satellite observation data using a static baseline solution mode and calculate the static three-dimensional coordinates of each monitoring station through adjustment.

[0007] Step 3: Calculate the real-time 3D coordinates (X, Y, Z) of each monitoring station using the RTK real-time algorithm, and then subtract the real-time 3D coordinates from the static 3D coordinates to obtain the real-time deformation (ΔX, ΔY, ΔZ) of each monitoring station.

[0008] Step 4: Establish a station center coordinate system with each monitoring station as the origin, and then convert the real-time deformation variables (ΔX, ΔY, ΔZ) into three-dimensional deformation variables (ΔE, ΔN, ΔU) in the station center coordinate system;

[0009] Step 5: Construct the dam coordinate system corresponding to each monitoring station and calculate the rotation angle γ between the dam coordinate system and the station center coordinate system;

[0010] Step 6: Based on the rotation angle γ, the three-dimensional deformation variables (ΔE, ΔN, ΔU) of each monitoring station in the station center coordinate system are converted into three-dimensional deformation variables (ΔE′, ΔN′, ΔU′) in the dam body coordinate system.

[0011] Furthermore, the present invention also discloses a real-time dam deformation monitoring system based on GNSS satellites corresponding to the above method, which mainly includes a GNSS base station, a GNSS monitoring station and a data processing center; the GNSS base station and the GNSS monitoring station respectively upload the received real-time satellite data to the data processing center; the data processing center is constructed to: use any one of the real-time dam deformation monitoring methods described above to perform real-time monitoring of dam deformation.

[0012] The present invention can convert the deformation results of the station center coordinate system of each monitoring station into the dam body coordinate system, which is convenient for dam management personnel to analyze the health status of the dam and has important reference significance for industries such as dam deformation monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a flow chart of the coordinate conversion algorithm for real-time dam deformation monitoring based on GNSS according to the present invention;

[0014] Figure 2 The rotation angle γ between the station center coordinate system and the dam coordinate system is determined by the two monitoring stations;

[0015] Figure 3 It is the rotation relationship between the station center coordinate system and the dam coordinate system. DETAILED DESCRIPTION

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0017] like Figure 1 As shown, the embodiment discloses a real-time dam deformation monitoring method based on GNSS, which mainly includes the following steps:

[0018] Step 1: The GNSS base station and each GNSS monitoring station upload real-time satellite data received in accordance with a specified data protocol (e.g., RTCM protocol) to a data processing center via a 4G / 5G wireless network or a wired network. The data processing center parses the real-time satellite data received from the GNSS base station and monitoring station according to the protocol (e.g., RTCM protocol) to obtain satellite observation data such as pseudorange, carrier phase, and signal-to-noise ratio.

[0019] Step 2: The data processing center uses the static baseline solution mode to process the received observation data of the base station and monitoring station, and obtains the static three-dimensional coordinates of each monitoring station through adjustment calculation. The specific process is as follows:

[0020] A baseline can be formed between each monitoring station and a reference station. When there are more than two monitoring stations, at least three baselines are formed between the reference stations and the monitoring stations, thus forming a baseline network. Specifically, the data processing center processes the satellite observations of the reference station and multiple monitoring stations obtained in step 1 according to the static baseline solution mode to obtain the baseline vector ΔdX of each baseline. ij and its covariance matrix D ij The inverse matrix of

[0021]

[0022]

[0023] in,

[0024] Where i and j are the station numbers, which can be monitoring stations or reference stations. are the approximate coordinates of site i, is the approximate coordinate of site j, “approximate coordinate” is also called “rough coordinate”; P ij is the weight matrix of the baseline vector (the weight matrix is ​​the inverse matrix of the covariance matrix); ΔX ij , ΔY ij , ΔZ ij are the differences in X, Y, and Z coordinates between the two sites, respectively; ΔX ij , ΔY ij , ΔZ ij variance; ΔX ij , ΔY ij , ΔX ij The covariance between each pair; n is the total number of reference stations and monitoring stations.

[0025] It should be noted that the present invention adopts a static baseline solution mode to obtain millimeter-level precision coordinate results, which can further ensure the accuracy of the calculation.

[0026] Calculate the three-dimensional coordinate difference of the baseline vector, that is, the adjustment value of the baseline vector observation value. The calculation formula is:

[0027]

[0028] Where, is the baseline vector observation value ΔX ij , ΔY ij , ΔZ ij 3D adjustment value of ; ΔX ij , ΔY ij , ΔZ ij The residuals of the observations.

[0029] Among them, the error equation of the baseline vector is:

[0030]

[0031] Where, are the coordinate correction values ​​of site j respectively; are the coordinate correction values ​​of site i respectively; are the approximate coordinates of site j; are the approximate coordinates of site i; is the difference between the approximate coordinates of monitoring stations i and j.

[0032] Assumptions:

[0033]

[0034] Then the baseline vector error equation numbered K is:

[0035]

[0036] In the formula, K represents the baseline number, 3*1 represents 3 rows and 1 column, It is expressed as follows:

[0037]

[0038] When there are m monitoring stations and n baseline vectors in the baseline network, the error equation of the n baseline vectors is:

[0039]

[0040] Among them, matrix B is the construction matrix of the baseline network, and the design matrix of the baseline vector labeled K is:

[0041]

[0042] I is the 3*3 order identity matrix; -I is located in the matrix The position of the jth monitoring station in the matrix; I is located at the position of the i-th monitoring station in the matrix. Therefore, the construction matrix B of n baseline vectors is:

[0043]

[0044] Where B i The structure of (i=1,2,…n) is similar to that of equation (8), except that it depends on the positions of the two monitoring station numbers on the baseline vector.

[0045] The approximate coordinates of each monitoring station after adjustment are:

[0046]

[0047] Where, is the approximate coordinates of each monitoring station after adjustment, that is, the static three-dimensional coordinates of the monitoring station obtained by static mode solution; (X 0 , Y 0 , Z 0 ) are the approximate coordinates of each monitoring station; It is the coordinate correction value of each monitoring station after adjustment.

[0048] Step 3. After the static three-dimensional coordinates of the monitoring station are calculated, the data processing center uses the GNSS base station and the real-time monitoring data stream to calculate the real-time three-dimensional coordinates (X, Y, Z) of each monitoring station using the RTK real-time algorithm. The real-time three-dimensional coordinates are then subtracted from the static three-dimensional coordinates obtained in step 2 to obtain the real-time deformation (ΔX, ΔY, ΔZ) of each monitoring station.

[0049] It should be noted that because the monitoring stations do not have precise coordinates, in step 2, the data processing center receives real-time data from the base and monitoring stations and uses a static solution mode to obtain the static three-dimensional coordinates of each monitoring station. In step 3, the data processing center uses a dynamic data processing method to obtain the real-time three-dimensional coordinates of each monitoring station. The main purpose is to obtain a coordinate sequence for each monitoring station. Both steps 3 and 2 process the real-time data stream received by the data processing center. Compared to step 2, step 3 can calculate the real-time deformation of the monitoring station every second, meaning the processing frequency can be set to seconds.

[0050] The method of using the RTK real-time algorithm to obtain the real-time three-dimensional coordinates (X, Y, Z) of each monitoring station specifically includes:

[0051] First, the pseudorange and carrier phase observation values ​​are inter-station and inter-satellite differenced to form a double difference observation equation:

[0052]

[0053] Where, P i is the pseudorange observation equation of satellite frequency i; is the carrier phase observation value; N i is the double-difference integer ambiguity; ρ is the geometric distance between the satellite and the reference station or monitoring station; λ i is the wavelength of satellite frequency i; Trop is the tropospheric error; are the observation noises of pseudorange and carrier phase respectively; is the double difference operator.

[0054] Then, the Kalman filter is used to solve the estimated parameter X(t). The estimated parameter X(t) is also the floating-point solution of the double-difference ambiguity parameter, which consists of the three-dimensional coordinate correction of each monitoring station and the double-difference integer ambiguity:

[0055]

[0056] Where dX is the three-dimensional coordinate correction of each monitoring station, is the double-difference integer ambiguity. The superscripts G, C, R, and E represent GPS satellites, BDS satellites, GLONASS satellites, and Galileo satellites, respectively.

[0057] The floating-point solution X(t) of the double-difference ambiguity parameters and its variance-covariance matrix Q, obtained by Kalman filtering, are then fed into the Least Squares Ambiguity Reduction and Correlation Adjustment (LAMBDA) algorithm to obtain a fixed solution (i.e., an integer solution) for the double-difference integer ambiguity parameters. Once the ambiguities are fixed, the real-time 3D coordinates of the monitoring station are obtained. The LAMBDA algorithm is currently the most efficient method for ambiguity fixing and is widely used in the industry.

[0058] Finally, the static three-dimensional coordinates of each monitoring station obtained in step 2 are used By subtracting the real-time three-dimensional coordinates (X, Y, Z) of each monitoring station obtained by the RTK dynamic algorithm in step 3, the real-time deformation (ΔX, ΔY, ΔZ) of each monitoring station can be obtained, that is:

[0059]

[0060] Step 4: Establish a station-centered coordinate system (ENU coordinate system) with each monitoring station as the origin, and then convert the real-time three-dimensional deformation variables (ΔX, ΔY, ΔZ) into three-dimensional deformation variables (ΔE, ΔN, ΔU) in the station-centered coordinate system.

[0061] Specifically, a station-centered coordinate system (ENU coordinate system) is established with the monitoring station as the origin. The origin can be the phase center of the antenna of each monitoring station. The coordinate axis E (abbreviated as "E axis") points eastward as positive, the N axis is perpendicular to the E axis and points northward as positive, and the U axis is perpendicular to the plane formed by the E and N axes and points upward as positive. The real-time three-dimensional deformation variables (ΔX, ΔY, ΔZ) are then converted into real-time three-dimensional deformation variables (ΔE, ΔN, ΔU) in the station-centered coordinate system:

[0062]

[0063] Where (B, L, H) is the geodetic coordinate, B is the latitude, L is the longitude, and H is the geodetic height.

[0064] The geodetic coordinates (B, L, H) can be obtained through the spatial rectangular coordinates (X, Y, Z), that is:

[0065]

[0066] in,

[0067]

[0068] Where N is the radius of the circle; e is the first eccentricity of the reference ellipsoid (specifically, the reference ellipsoid in the CGCS2000 or WGS84 coordinate system standard can be used); f is the flattening of the reference ellipsoid, a is the semi-major axis of the reference ellipsoid; b is the semi-minor axis of the reference ellipsoid.

[0069] Step 5: Construct the dam coordinate system corresponding to each monitoring station, and then calculate the rotation angle γ between the dam coordinate system and the station center coordinate system.

[0070] Combine Figure 2 and Figure 3 As shown in Figure 1, the origin of the dam coordinate system (E′N′U′ coordinate system) can specifically be the phase center of each monitoring station's antenna. The E′ axis is positive along the downstream direction of the water flow, the N′ axis is perpendicular to the E′ axis and forms a right-handed coordinate system with the E′ axis, and the U′ axis is perpendicular to the plane formed by the E′ and N′ axes and is positive when pointing toward the sky. Therefore, the station-centered coordinate system (ENU coordinate system) centered on the monitoring station and the dam coordinate system (E′N′U′ coordinate system) share a common origin and have coincident Z axes. The dam coordinate system can be obtained by rotating the station-centered coordinate system around the Z axis.

[0071] Usually, when the monitoring stations are arranged, they are parallel to the dam. Therefore, the azimuth angle calculated by projecting the two monitoring stations on the station center coordinate system is the rotation angle γ. The specific steps include:

[0072] First, we randomly select two monitoring stations along the positive direction of the N′ axis. The rear monitoring station is the master station (assuming it is monitoring station M1), and the front monitoring station is the slave station (assuming it is monitoring station M2). Since the static three-dimensional coordinates of the monitoring stations have been calculated in step 2, the three-dimensional coordinate deviation can be obtained by subtracting the static three-dimensional coordinates of the two monitoring stations (ΔX 21 ,ΔY 21 ,ΔZ 21 ).

[0073] Then, with monitoring station M1 as the origin of the station center coordinate system and monitoring station M2 as the observation point, the coordinates of observation point M2 are converted to the station center coordinate system as follows:

[0074]

[0075] Where, (ΔE 21 ,ΔN 21 ,ΔU 21 ) is the station center coordinate of observation point M2 in the station center coordinate system of M1; (B1, L1, H1) is the geodetic coordinate of monitoring station M1.

[0076] Finally, the rotation angle γ can be calculated through the relationship between the E-axis coordinate and the N-axis coordinate. The γ angle calculation formula is:

[0077]

[0078] Step 6. After calculating the rotation angle γ, the three-dimensional deformation variables (ΔE, ΔN, ΔU) of each monitoring station in the station center coordinate system can be rotated to obtain the three-dimensional deformation variables (ΔE′, ΔN′, ΔU′) in the dam coordinate system, that is:

[0079]

[0080] in, Figure 2 The rotation angle γ is determined by projecting from the monitoring station to the main monitoring station in the station center coordinate system and using the E and N coordinate relationship. Figure 3 It is the rotation relationship between the station center coordinate system and the dam coordinate system. The dam coordinate system can convert the deformation variable in the station center coordinate system into the deformation variable in the dam coordinate system through the rotation angle γ.

[0081] Another embodiment of the present invention discloses a real-time dam deformation monitoring system based on GNSS satellites, which mainly includes a GNSS reference station, a GNSS monitoring station, and a data processing center. The GNSS reference station and the GNSS monitoring station respectively upload received real-time satellite data to the data processing center. The data processing center is constructed as follows:

[0082] Obtain real-time satellite data uploaded by GNSS base stations and monitoring stations, and perform data analysis on the real-time satellite data to obtain satellite observation data of each monitoring station;

[0083] Use static data processing to obtain the static three-dimensional coordinates of each monitoring station

[0084] The real-time three-dimensional coordinates (X, Y, Z) of each monitoring station are calculated using the RTK real-time algorithm, and then the real-time three-dimensional coordinates are subtracted from the static three-dimensional coordinates to obtain the real-time deformation (ΔX, ΔY, ΔZ) of each monitoring station;

[0085] Establish a station center coordinate system with each monitoring station as the origin, and then convert the real-time deformation variables (ΔX, ΔY, ΔZ) into three-dimensional deformation variables (ΔE, ΔN, ΔU) in the station center coordinate system;

[0086] Construct the dam coordinate system corresponding to each monitoring station respectively, and calculate the rotation angle γ between the dam coordinate system and the station center coordinate system;

[0087] Based on the rotation angle γ, the three-dimensional deformation variables (ΔE, ΔN, ΔU) of each monitoring station in the station center coordinate system are converted into three-dimensional deformation variables (ΔE′, ΔN′, ΔU′) in the dam body coordinate system.

[0088] It can be understood that the specific manner in which the data processing center completes the above process can refer to the method involved in the aforementioned embodiment, which will not be repeated here.

[0089] Finally, it should be noted that the above content merely illustrates the technical idea of ​​the present invention and cannot be used to limit the scope of protection of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications all fall within the scope of protection of the claims of the present invention.

Claims

1. A real-time dam deformation monitoring method based on GNSS satellites, characterized in that: include: Step 1: Receive real-time satellite data uploaded by the GNSS reference station and the GNSS monitoring station, and parse the real-time satellite data to obtain satellite observation data of each monitoring station; Step 2: Process the satellite observation data using a static baseline solution mode and calculate the static three-dimensional coordinates of each monitoring station through adjustment. Step 3: Calculate the real-time 3D coordinates (X, Y, Z) of each monitoring station using the RTK real-time algorithm, and then subtract the real-time 3D coordinates from the static 3D coordinates to obtain the real-time deformation (ΔX, ΔY, ΔZ) of each monitoring station. Step 4: Establish a station center coordinate system with each monitoring station as the origin, and then convert the real-time deformation variables (ΔX, ΔY, ΔZ) into three-dimensional deformation variables (ΔE, ΔN, ΔU) in the station center coordinate system; Step 5: Construct the dam coordinate system corresponding to each monitoring station and calculate the rotation angle γ between the dam coordinate system and the station center coordinate system; Step 6: Based on the rotation angle γ, the three-dimensional deformation variables (ΔE, ΔN, ΔU) of each monitoring station in the station center coordinate system are converted into three-dimensional deformation variables (ΔE′, ΔN′, ΔU′) in the dam body coordinate system; In step 4, the origin of the station center coordinate system is the phase center of the antenna of each monitoring station, the coordinate axis E is positive when it points to the east, the N axis is perpendicular to the E axis and is positive when it points to the north, and the U axis is perpendicular to the plane formed by the E and N axes and is positive when it points to the sky; Convert the real-time three-dimensional deformation variables (ΔX, ΔY, ΔZ) of each monitoring station into real-time three-dimensional deformation variables (ΔE, ΔN, ΔU) in the station center coordinate system: Where (B, L, H) is the geodetic coordinate, B is the latitude, L is the longitude, and H is the geodetic height; In step 5, the origin of the dam coordinate system is the phase center of the antenna of each monitoring station, wherein the E' axis is positive along the downstream direction of the water flow, the N' axis is perpendicular to the E' axis and forms a right-handed coordinate system with the E' axis, and the U' axis is perpendicular to the plane formed by the E' axis and the N' axis and is positive when pointing to the sky; the station center coordinate system ENU and the dam coordinate system E'N'U' have a common coordinate origin and the Z axes coincide, and the dam coordinate system is obtained by rotating the station center coordinate system around the Z axis; The method for obtaining the rotation angle γ is as follows: First, take any two monitoring stations along the positive direction of the N′ axis. The rear monitoring station M1 is the master station, and the front monitoring station M2 is the slave station. By taking the difference between the static three-dimensional coordinates of the two monitoring stations, the three-dimensional coordinate deviation is (ΔX 21 ,ΔY 21 ,ΔZ 21 ); Then, with monitoring station M1 as the origin of the station center coordinate system and monitoring station M2 as the observation point, the coordinates of observation point M2 are converted to the station center coordinate system as follows: Where, (ΔE 21 ,ΔN 21 ,ΔU 21 ) is the station center coordinate of the observation point M2 in the station center coordinate system of M1; (B1, L1, H1) is the geodetic coordinate of the monitoring station M1; Finally, the rotation angle γ can be calculated through the relationship between the E-axis coordinate and the N-axis coordinate. The γ angle calculation formula is:

2. The real-time dam deformation monitoring method according to claim 1, characterized in that: In step 1, the satellite observation data at least includes carrier phase observation values ​​and pseudorange observation values.

3. The real-time dam deformation monitoring method according to claim 1, characterized in that: In step 1, the real-time satellite data complies with RTCM protocol requirements, and the real-time satellite data is parsed based on the RTCM protocol.

4. The real-time dam deformation monitoring method according to claim 1, characterized in that: The step 2 specifically includes: The satellite observation data of the reference station and the monitoring station are processed according to the static baseline solution mode to obtain the baseline vector ΔdX of each baseline. ij and its weight matrix P ij as follows: in, Where i, j are the station numbers, i, j = 1, 2, ... n; are the approximate coordinates of site i, is the approximate coordinate of site j; P ij is the weight matrix of the baseline vector, which is also the covariance matrix D ij The inverse matrix of ΔX ij , ΔY ij , ΔZ ij are the differences in X, Y, and Z coordinates between the two sites, respectively; ΔX ij , ΔY ij , ΔZ ij variance; ΔX ij , ΔY ij , ΔX ij The covariance between the two; n is the total number of reference stations and monitoring stations; Calculate the three-dimensional coordinate difference of the baseline vector, that is, the adjustment value of the baseline vector observation value: Where, is the baseline vector observation value ΔX ij , ΔY ij , ΔZ ij 3D adjustment value of ; ΔX ij , ΔY ij , ΔZ ij The residual of the observation value; Among them, the error equation of the baseline vector is: Where, are the coordinate correction values ​​of site j respectively; are the coordinate correction values ​​of site i respectively; are the approximate coordinates of site j; are the approximate coordinates of site i; is the difference between the approximate coordinates of monitoring stations i and j; Assumptions: Then the baseline vector error equation numbered K is: In the formula, K represents the baseline number, 3*1 represents 3 rows and 1 column, It is expressed as follows: When there are m monitoring stations and n baseline vectors in the baseline network, the error equation of the n baseline vectors is: Among them, matrix B is the construction matrix of the baseline network, and the design matrix of the baseline vector labeled K is: I is the 3*3 order identity matrix; -I is located in the matrix The jth monitoring station in the matrix; I is located at the i-th monitoring station in the matrix; the construction matrix B of n baseline vectors is: The approximate coordinates of each monitoring station after adjustment are: Where, is the approximate coordinates of each monitoring station after adjustment, that is, the static three-dimensional coordinates of the monitoring station obtained by static mode solution; (X 0 , Y 0 , Z 0 ) are the approximate coordinates of each monitoring station; It is the coordinate correction value of each monitoring station after adjustment.

5. The real-time dam deformation monitoring method according to claim 1, characterized in that: The step 3 specifically includes: First, the pseudorange observation values ​​and carrier observation values ​​in the satellite observation data are inter-station and inter-satellite differenced to form a double difference observation equation: Where, P i is the pseudorange observation equation of satellite frequency i; is the carrier phase observation value; N i is the double-difference integer ambiguity; ρ is the geometric distance between the satellite and the reference station or monitoring station; λ i is the wavelength of satellite frequency i; Trop is the tropospheric error; are the observation noises of pseudorange and carrier phase respectively; Δ▽ is the double difference operator; Then, the Kalman filter is used to solve the estimated parameter X(t). The estimated parameter X(t) is also the floating-point solution of the double-difference ambiguity parameter, which consists of the three-dimensional coordinate correction of each monitoring station and the double-difference integer ambiguity: X(t)=[dX,Δ▽N G ,Δ▽N C ,Δ▽N R ,Δ▽N E ] (12) Where dX is the three-dimensional coordinate correction of each monitoring station, Δ▽N is the double-difference integer ambiguity, and the superscripts G, C, R, and E represent GPS satellites, BDS satellites, GLONASS satellites, and Galileo satellites, respectively. Then, the floating-point solution X(t) of the double-difference ambiguity parameters and its variance-covariance Q are introduced into the least squares ambiguity reduction and correlation adjustment algorithm to obtain the fixed solution of the double-difference integer ambiguity parameters. After the ambiguity is fixed, the real-time three-dimensional coordinates of the monitoring station are obtained. Finally, the static three-dimensional coordinates of each monitoring station Subtract the real-time three-dimensional coordinates (X, Y, Z) to obtain the real-time deformation (ΔX, ΔY, ΔZ) of each monitoring station, that is:

6. The real-time dam deformation monitoring method according to claim 1, characterized in that: The geodetic coordinates (B, L, H) are obtained through the spatial rectangular coordinates (X, Y, Z), that is: in, Where N is the radius of the ellipse; e is the first eccentricity of the reference ellipsoid; f is the flattening of the reference ellipsoid, a is the semi-major axis of the reference ellipsoid; b is the semi-minor axis of the reference ellipsoid.

7. The real-time dam deformation monitoring method according to claim 1, characterized in that: In step 6, the formula for converting the three-dimensional deformation variables (ΔE, ΔN, ΔU) of each monitoring station in the station center coordinate system into the three-dimensional deformation variables (ΔE′, ΔN′, ΔU′) in the dam body coordinate system is as follows:

8. A real-time dam deformation monitoring system based on GNSS satellites, characterized in that: The system comprises a GNSS base station, a GNSS monitoring station and a data processing center; the GNSS base station and the GNSS monitoring station respectively upload received real-time satellite data to the data processing center; the data processing center is constructed to: use the real-time dam deformation monitoring method according to any one of claims 1 to 7 to monitor dam deformation in real time.

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