AU2020101382A4

AU2020101382A4 - Method and system for real-time tilt monitoring of transmission tower

Info

Publication number: AU2020101382A4
Application number: AU2020101382A
Authority: AU
Inventors: Zhouzheng GAO; Jie Lv; Junhuan PENG
Original assignee: China University of Geosciences Beijing
Current assignee: China University of Geosciences Beijing
Priority date: 2019-12-06
Filing date: 2020-07-16
Publication date: 2020-09-03
Anticipated expiration: 2028-07-16
Also published as: CN110986879A; CN110986879B

Abstract

The present invention discloses a method and system for real-time tilt monitoring of a transmission tower. The method includes: obtaining IMU data collected by an inertial sensor and GNSS data provided by a dual-antenna GNSS system, where both the inertial sensor and the dual-antenna GNSS system are installed on a transmission tower; synchronizing the IMU data and the GNSS data; transmitting the synchronized IMU data and GNSS data to a control system end in real time; calculating, by the control system end, a first parameter based on the IMU data, where the first parameter includes a position, a velocity, and a heading angle of a first antenna; calculating, by the control system end, a second parameter based on the GNSS data, where the second parameter includes the position and the velocity of the first antenna, and a heading angle of a baseline between dual antennas; performing, by using an extended Kalman filter algorithm, LCI calculation using the first parameter and the second parameter, to determine a position, a velocity, and a heading angle of the transmission tower; and determining a tilt of the transmission tower based on the heading angle of the transmission tower. The present invention can implement real-time and high-accuracy tilt monitoring for transmission towers.

Description

I

METHOD AND SYSTEM FOR REAL-TIME TILT MONITORING OF TRANSMISSION TOWER TECHNICAL FIELD The present invention relates to the technical field of electric power equipment, and in particular, to a method and system for real-time tilt monitoring of a transmission tower. BACKGROUND Real-time tilt monitoring of high-voltage transmission towers is the core technical support for maintaining power transmission safety. Currently, tilt monitoring of high-voltage power towers is mainly based on regular or irregular inspections. This cannot implement continuous, real-time, and high-accuracy tilt monitoring for transmission towers, or ensure the power transmission safety. SUMMARY The present invention is intended to provide a method and system for real-time tilt monitoring of a transmission tower, and to implement real-time and high-accuracy tilt monitoring for transmission towers. To achieve the above purpose, the present invention provides the following technical solutions. A method for real-time tilt monitoring of a transmission tower includes: obtaining Inertial Measurement Unit (IMU) data collected by an inertial sensor and Global Navigation Satellite System (GNSS) data provided by a dual-antenna GNSS system, where both the inertial sensor and the dual-antenna GNSS system are installed on a transmission tower; synchronizing the IMU data and the GNSS data; transmitting the synchronized IMU data and GNSS data to a control system end in real time; calculating, by the control system end, a first parameter based on the IMU data, where the first parameter includes a position, a velocity, and a heading angle of a first antenna; calculating, by the control system end, a second parameter based on the GNSS data, where the second parameter includes the position and the velocity of the first antenna, and a heading angle of a baseline between dual antennas; performing, by using an extended Kalman filter algorithm, Loose Coupled Integration (LCI) calculation using the first parameter calculated from the IMU data and the second parameter calculated from the GNSS data, to determine a position, a velocity, and a heading angle of the transmission tower; and determining a tilt of the transmission tower based on the heading angle of the transmission tower. Optionally, the synchronizing the IMU data and the GNSS data specifically includes: connecting a GNSS signal and an IMU signal simultaneously to an FPGA board; decoding GPS, BDS, GLONASS, and Galileo from the GNSS signal to obtain time information; to the FPGA board; calculating time information of the IMU signal, denoted as IMU signal initial time, based on the decoded time information of GPS, BDS, GLONASS, and Galileo and the time difference; and determining, based on the IMU signal initial time and an IMU sampling rate, time information of IMU data to be subsequently input to the FPGA board. Optionally, the transmitting the synchronized IMU data and GNSS data to a control system end specifically includes: transmitting the synchronized IMU data and GNSS data to the control system end in real time through 4G/5G. Optionally, before the calculating a second parameter based on the GNSS data, the method further includes: obtaining GNSS system parameters solved by International GNSS Service center (IGS), where the parameters include a precise orbit, a real-time precision clock offset, an ionospheric parameter, a satellite's differential code bias, and an uncalibrated phase delay of a satellite. Optionally, the calculating a second parameter based on the GNSS data specifically includes: performing Real-Time Precise Point Positioning (RT-PPP) position and velocity calculation on the first antenna based on GNSS data of the first antenna and the parameters of the GNSS system solved by the IGS, to obtain an absolute position and velocity of the first antenna under an earth centered earth fixed frame; using the first antenna as a reference station and a second antenna as a rover station to perform ultra-short baseline Real-Time Kinematic (RTK) calculation based on the GNSS data of the first antenna and GNSS data of the second antenna, to obtain a baseline vector between the first antenna and the second antenna; and converting the baseline vector to a navigation frame and determining a heading angle of the baseline vector in the navigation frame. The present invention further provides a system for real-time tilt monitoring of a transmission tower, including: a control system end, an inertial sensor and a dual-antenna GNSS system installed on a transmission tower, an FPGA board, and a data transmission module, where the FPGA board includes a data obtaining module and a data synchronization module; the control system end includes an IMU data calculation module, a GNSS data calculation module, an LCI calculation module, and a tilt determining module; the data obtaining module is configured to obtain IMU data collected by the inertial sensor and GNSS data provided by the dual-antenna GNSS system; the data synchronization module is configured to synchronize the IMU data and the GNSS data; the data transmission module is configured to transmit the synchronized IMU data and GNSS data to the control system end in real time; data, where the first parameter includes a position, a velocity, and a heading angle of a first antenna; the GNSS data calculation module is configured to calculate a second parameter based on the GNSS data, where the second parameter includes the position and the velocity of the first antenna, and a heading angle of a baseline between dual antennas; the LCI calculation module is configured to perform LCI calculation using the first parameter and the second parameter by using an extended Kalman filter algorithm, to determine a position, a velocity, and a heading angle of the transmission tower; and the tilt determining module is configured to determine a tilt of the transmission tower based on the heading angle of the transmission tower. Optionally, the data synchronization module specifically includes: a signal access unit, configured to connect a GNSS signal and an IMU signal simultaneously to the FPGA board; a decoding unit, configured to decode GPS, BDS, GLONASS, and Galileo from the GNSS signal to obtain time information; a time difference determining unit, configured to determine a time difference between the GNSS signal and the IMU signal that are transmitted to the FPGA board; an IMU signal initial time information synchronization unit, configured to calculate time information of the IMU signal, denoted as IMU signal initial time, based on the decoded time information of GPS, BDS, GLONASS, and Galileo and the time difference; and an IMU signal time information synchronization unit, configured to determine, based on the IMU signal initial time and an IMU sampling rate, time information of IMU data to be subsequently input to the FPGA board. Optionally, the data transmission module specifically includes: a data transmission unit, configured to transmit the synchronized IMU data and GNSS data to the control system end in real time through 4G/5G. Optionally, the system further includes: a GNSS system parameter obtaining unit, configured to obtain GNSS system parameters solved by International GNSS Service center (IGS), where the parameters include a precise orbit, a real-time precision clock offset, an ionospheric parameter, a satellite's differential code bias, and an uncalibrated phase delay of a satellite. Optionally, the GNSS data calculation module specifically includes: a position and velocity calculation unit, configured to perform RT-PPP position and velocity calculation on the first antenna based on GNSS data of the first antenna and the parameters of the GNSS system solved by the IGS, to obtain an absolute position and velocity of the first antenna under an earth centered earth fixed frame; a baseline vector determining unit, configured to use the first antenna as a reference station and

GNSS data of the first antenna and GNSS data of the second antenna, to obtain a baseline vector between the first antenna and the second antenna; and a heading angle solution unit, configured to convert the baseline vector to a navigation frame and determine a heading angle of the baseline vector in the navigation frame. According to specific examples provided by the present invention, the present invention discloses the following technical effects: According to a method and system for real-time tilt monitoring of a transmission tower provided by the present invention, IMU data and GNSS data collected by an inertial sensor and a dual-antenna GNSS system that are installed on a transmission tower are transmitted to a control system end in real time through 4G/5G; and the control system end performs RT-PPP calculation on GNSS data of a primary antenna to obtain accurate coordinates of the antenna; performs RTK calculation based on GNSS data of dual antennas to obtain a high-accuracy baseline result and calculate a heading angle and an attitude angle determined by the dual antennas; and performs GNSS/INS loosely coupled integration based on the position of the primary antenna, the heading angle and the attitude angle determined by the dual antennas, and the IMU data, to calculate a position, a velocity, and an attitude of the transmission tower. This can implement fast and effective real-time high-accuracy monitoring of an absolute position and tilt of the high-voltage transmission tower. According to another aspect of the invention there is provided a method for real-time tilt monitoring of a transmission tower, comprising: obtaining Inertial Measurement Unit (IMU) data collected by an inertial sensor and Global Navigation Satellite System (GNSS) data provided by a dual-antenna GNSS system, wherein both the inertial sensor and the dual-antenna GNSS system are installed on a transmission tower; synchronizing the IMU data and the GNSS data; transmitting the synchronized IMU data and GNSS data to a control system end in real time; calculating, by the control system end, a first parameter based on the IMU data, wherein the first parameter comprises a position, a velocity, and a heading angle of a first antenna; calculating, by the control system end, a second parameter based on the GNSS data, wherein the second parameter comprises the position and the velocity of the first antenna, and a heading angle of a baseline between dual antennas; performing, by using an extended Kalman filter algorithm, Loose Coupled Integration (LCI) calculation using the first parameter calculated from the IMU data and the second parameter calculated from the GNSS data, to determine a position, a velocity, and a heading angle of the transmission tower; and determining a tilt of the transmission tower based on the heading angle of the transmission tower. According to another aspect of the invention there is provided a system for real-time tilt dual-antenna GNSS system installed on a transmission tower, an FPGA board, and a data transmission module, wherein the FPGA board comprises a data obtaining module and a data synchronization module; the control system end comprises an IMU data calculation module, a GNSS data calculation module, an LCI calculation module, and a tilt determining module; the data obtaining module is configured to obtain IMU data collected by the inertial sensor and GNSS data provided by the dual-antenna GNSS system; the data synchronization module is configured to synchronize the IMU data and the GNSS data; the data transmission module is configured to transmit the synchronized IMU data and GNSS data to the control system end in real time; the IMU data calculation module is configured to calculate a first parameter based on the IMU data, wherein the first parameter comprises a position, a velocity, and a heading angle of a first antenna; the GNSS data calculation module is configured to calculate a second parameter based on the GNSS data, wherein the second parameter comprises the position and the velocity of the first antenna, and a heading angle of a baseline between dual antennas; the LCI calculation module is configured to perform LCI calculation using the first parameter and the second parameter by using an extended Kalman filter algorithm, to determine a position, a velocity, and a heading angle of the transmission tower; and the tilt determining module is configured to determine a tilt of the transmission tower based on the heading angle of the transmission tower. Any one of the terms: including or which includes or that includes as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising. It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country BRIEF DESCRIPTION OF DRAWINGS To describe the technical solutions in the examples of the present invention or in the prior art more clearly, the following briefly introduces the accompanying drawings required for describing the examples. Apparently, the accompanying drawings in the following description show merely some examples of the present invention, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts. FIG. 1 is a schematic diagram of a connection relationship between some components in a system for real-time tilt monitoring of a transmission tower according to an example of the present invention. FIG. 2 is a flowchart of a system for real-time tilt monitoring of a transmission tower according

DETAILED DESCRIPTION The following clearly and completely describes the technical solutions in the examples of the present invention with reference to accompanying drawings in the examples of the present invention. Apparently, the described examples are merely a part rather than all of the examples of the present invention. All other examples obtained by a person of ordinary skill in the art based on the examples of the present invention without creative efforts shall fall within the protection scope of the present invention. The present invention is intended to provide a method and system for real-time tilt monitoring of a transmission tower, to implement real-time and high-accuracy tilt monitoring for transmission towers. In order to make the above objectives, features, and advantages of the present invention more understandable, the present invention will be described in further detail below with reference to the accompanying drawings and detailed examples. The following explains some terms used in the present invention: 4G/5G: The 4 / 5th Generation Mobile Communication Technology GPS: Global Positioning System GLONASS: Global Navigation Satellite System BDS3: 3 rd BeiDou Satellite Navigation System Galileo: Galileo Satellite Navigation System GNSS: Global Navigation Satellite Systems IGS: International GNSS Service Center IMU: Inertial Measurement Unit INS: Inertial Navigation System FPGA: Field Programmable Gate Array RT-PPP: Real-Time Precise Point Positioning RTK: Real-time Kinematic LCI: Loosely Coupled Integration According to the present invention, a 4G/5G communication module, a low-cost inertial sensor, a dual-antenna multi-system GNSS (including BDS, GPS, GLONASS, and Galileo) receiver constitute a user-end data collection and broadcast system. Based on GNSS system time, the system calculates a time difference between a GNSS input signal and an IMU input signal on an FPGA board, determines time of IMU data, and complete time synchronization between GNSS and IMU data. The 4G/5G communication module sends pseudo-range, carrier-phase, and Doppler information of the dual-antenna multi-system GNSS and specific force and angular velocity information collected by an IMU after time synchronization to a control system end. The control system end determines absolute positions and attitudes of GNSS dual antennas by using RT-PPP -- A DTI7 -- ~A TO i_-+_- 1~~ +I,-~ A-1 _+A A-+- tin_ dual-antenna GNSS RTK position data, and INS data to implement fast and effective real-time high-accuracy monitoring of absolute positions and tilt of high-voltage transmission towers. As shown in FIG. 1, centering on a low-cost inertial sensor 2, a forward-right-down body frame (b frame) is established, and an antenna r1 and an antenna r2 of a dual-antenna multi-system GNSS receiver 1 are installed on a forward/x axis, where the antenna r1 is close to an IMU, and a distance from the antenna r to a lever arm of the IMU is (r,0,z . The two antennas are connected to the dual-antenna multi-system GNSS receiver 1, and the GNSS receiver 1 and the low-cost inertial sensor 2 are connected to an FPGA board 3, to implement time synchronization between GNSS data and IMU data on the FPGA board 3. The synchronized dual-antenna GNSS data and INS data are transmitted back to a control system end through a 4G/5G communication module 4, and real-time position, velocity, and attitude information of each transmission tower is accurately calculated by using GNSS/INS LCI algorithm. In an example, as shown in FIG. 2, a method for real-time tilt monitoring of a transmission tower according to the present invention includes the following steps: Step 201: Obtain IMU data collected by an inertial sensor and GNSS data provided by a dual-antenna GNSS system, where both the inertial sensor and the dual-antenna GNSS system are installed on a transmission tower. Step 202: Synchronize the IMU data and the GNSS data. Step 203: Transmit the synchronized IMU data and GNSS data to a control system end in real time. Step 204: The control system end calculates a first parameter based on the IMU data, where the first parameter includes a position, a velocity, and a heading angle of a first antenna. Step 205: The control system end calculates a second parameter based on the GNSS data, where the second parameter includes the position and the velocity of the first antenna, and a heading angle of a baseline between dual antennas. Step 206: Perform, by using an extended Kalman filter algorithm, LCI calculation using the first parameter calculated from the IMU data and the second parameter calculated from the GNSS data, to determine a position, a velocity and a heading angle of the transmission tower. Step 207: Determine a tilt of the transmission tower based on the heading angle of the transmission tower. In the example, step 202 may be implemented in the following manner: Based on the electronic signal transmission theory, connect a dual-antenna multi-system GNSS signal and an IMU signal simultaneously to an FPGA board, and calculate time of the IMU signal based on a time difference of the two signals transmitted to the FPGA board and Time information of GPS, BDS, GLONASS, and Galileo decoded from the GNSS signal. Perform time synchronization for subsequently input IMU data based on a stable PPS signal of an IMU, the

In the example, step 203 may be implemented in the following manner: Based on the 4G/5G communication technology theory and digital encoding/decoding technology, transmit back the observed dual-antenna multi-system GNSS data and the synchronized IMU data to the control system end in real time, and decode the data according to a GNSS data format and an IMU data format. In the example, before step 205, the method further includes: based on the network data transmission technology and multi-system GNSS real-time precise orbit determining theory, transmitting multi-system GNSS real-time satellite products (including a precise orbit, a real-time precision clock offset, an ionospheric parameter, a satellite's differential code bias, and an uncalibrated phase delay of a satellite) solved by IGS to the control system in real time. In the example, step 205 may be implemented in the following manner: Based on the RT-PPP theory, perform RT-PPP position and velocity calculation by using the input real-time multi-system GNSS data (pseudo-range, carrier-phase, and Doppler) of the first antenna r1 and real-time precise satellite products, to obtain a real-time and high-accuracy absolute position (Prl) and velocity (Vrl) of the high-voltage transmission tower under an Earth Centered Earth Fixed frame (e frame); based on the double-difference GNSS baseline solution theory, use the antenna rI as a reference station and a second antenna r2 of the GNSS system as a rover station to perform ultra-short baseline RTK solution and obtain a position (Pr2) of the antenna r2 and a baseline vector AL between the antennas r1 and r2, whereAL"= p, - Pr2

based on the spatial coordinate system conversion principle, with the position of the antenna rI as the center, convert the baseline vector (AL) between the antennas rI and r2 to a North-East-Down (N-E-D, denoted as navigation frame or n frame), to obtain a baseline vector AL" = (ANrlr2 AErir2 ADrir2 ) under the n frame; and

based on the definition of a spatial heading angle, use the baseline vector AL under the n frame to calculate a heading angle rl-r2 =a tan 2(AErl-r2,ANrl-r2) corresponding to a baseline determined by the antennas rI and r2, where a tan 2 is a function used to calculate an azimuth in the C/C++ language, and a returned value is - 7 ~ + 7. In the example, step 205 may be implemented in the following manner: Based on the multi-source data fusion theory and extended Kalman filter theory, perform LCI solution by using the GNSS position, the heading angle determined by the antennas r1 and r2, and the IMU data. In the extended Kalman filter theory, an LCI observation equation and a state equation may be expressed as: ZLCI,k= HLCI,kXLCI,k+7LCI,k'ILCI,k~ N(0, RCI.,

XLCI,k = LCI,kk-1 LCIk-1 LCI,k-l' LCI,k-1 - N(0 IQ ) (2)

An adjustment solution and a variance corresponding to equations (1) and (2) may be expressed as: XLCIk =LCI,k/k-lXLCIk-I+KLCI,k(ZLCI,k HLCI,k LCIk/k-1KLCI,k-1)

LCI,k =(I KLCI,kHLC,k)LCI,k/k-1(I KLCI,kHLCI,kY +KLCI,kRLCIkKI1

where P P ~T LCI,klk-i LCI,klk-i LCI,k LCI,klk-i + LCI,k-1 (5)

KLCILk=LCICk/k1H k(HLCI,kPLC,kk-1HLC,k-1 +PLCI,k (6) ZLC X H k

In the formulas, LCI LCI, LCI, k,k-1 represent an LCI observation innovation vector, a state parameter vector, a design coefficient matrix, and a state transition matrix for predicting a state parameter vector at a moment k from a state parameter vector at a moment k-1; KLCI,k represents a Kalman filter gain matrix at the moment k; 'iLCI and k-1 represent LCI

observation vector noise and state noise, and their priori variances are RLCI and Qk ; N represents Gaussian normal distribution; and XLCI represents a state vector.

XLCI P,5",'P,M B,B,,,S,,Sa) (7)

In the formula, &P represents an attitude correction number vector (including a roll angle correction number, a pitch angle correction number, and a heading angle correction number); dBa

and "B9 represent bias correction number vectors of an accelerometer and a gyroscope; anddSa 6S and g represent scale factor correction number vectors of the accelerometer and the gyroscope. The observation innovation vector ( ZLCI) consists of three parts: a heading constraint equation, a position equation, and a velocity equation:

T-rl-r2 VT,k VT,k '(0,R,)

ZLCI,k Pr1 Pr,INS + Vp,k pk N (0,R) rV rl,INS ,J vk ,k K(,R,) (, ) (8) In the formula, 'P represents a heading angle calculated through INS mechanization; Pri and rl,INS represent a position of the antenna r solved through GNSS PPP (converted from PH) and a position of the antenna r calculated by the INS under the n frame, and are expressed e e

as geographical coordinates; V i and VrI, INS represent a velocity of the antenna rI solved through GNSS PPP (converted from Vr1) and a velocity of the antenna rI calculated by the INS; V, V VT~ and §),, , andVTF* represent observation noises of the position, the velocity, and the heading attitude, the expectation is zero, and priori variances are R, R', and RT. Because the center of the GNSS receiver does not coincide with the center of the IMU, the position and velocity solved by the GNSS and those calculated by the INS have the following relationship:

Pr1,k - Pr1,insk + D-IC, (9)

rlk rlins,k + in X)Cb,k rl b,k rl 1 b (10)

In the formulas, Cun represents an angular velocity, of the n frame relative to an inertial frame (i frame), projected to the n frame, "ib represents angular increment information measured by the IMU in the b frame (an angular velocity of the b frame relative to the i frame), and x represents a matrix cross-multiplication operation; C represents an attitude transition matrix from the n frame to the b frame; and D-1 represents a rotation matrix that converts an arm under the n frame to a geographic coordinate system.

'l1. 0/(R, + h) D-1 =1.0 /(RN +h)cos(Latigute) -1.0

In the formula, RN and RM represent the radius of curvature in the meridian and the radius of curvature in the prime vertical, h represents the elevation corresponding to the current IMU, and latitude represents the latitude corresponding to a position of the IMIJ. According to the error perturbation theory, perform error perturbation &ZLCI,k /XLCI on equation (8), to obtain a design coefficient matrix HLCI*. The state transition matrix is determined by the dynamics equation of the state parameter. In this solution, a PSI angular error model is used to describe the change law of the position, velocity, and attitude in time domain, and the first-order Gaussian Markov process is used to describe a bias error and a scale factor error of the inertial sensor. Continuous functions of the PSI angular error model may be expressed as:

p= co"e xdp,1 +v" (12) rl + Cngof x 5T ,5V"n = Cn"f X bb b- (C",in + Co ie Vnr(13) ,"X +,g

ofT in - C bn &co = -Co," x (5T ib(14) In the formulas, f ,g , and cie represent specific force information output by the accelerometer in the b frame, a projection of the gravitational acceleration in the n frame, and an angular velocity, of the e frame relative to the i frame, projected to the n frame. The continuous first-order Gaussian Markov process may be expressed as:

dx dx=--+e T (15)

In the formula, X = (B, Ba, S,, S), r represents time related to the first-order Gaussian Markov process, and E represents the first-order Gaussian Markov process noise. Based on equations (12) to (15), obtain a state transition coefficient matrix. Calculate precise three-dimensional position, velocity, and attitude information of the high-voltage transmission tower according to equation (3). Because the tilt of the transmission tower can be directly reflected by the calculated attitude angle, the dual-antenna multi-system GNSS PPP-RTK and INS real-time data processing algorithms can be used for real-time positioning, monitoring, and warning of the transmission tower subject to tilting, with the support of 4G/5G. The present invention further provides a system for real-time tilt monitoring of a transmission tower. The system includes: a control system end, an inertial sensor and a dual-antenna GNSS system installed on a transmission tower, an FPGA board, and a data transmission module. The FPGA board includes a data obtaining module and a data synchronization module. The control system end includes an IMU data calculation module, a GNSS data calculation module, an LCI calculation module, and a tilt determining module. The data obtaining module is configured to obtain IMU data collected by the inertial sensor and GNSS data provided by the dual-antenna GNSS system. The data synchronization module is configured to synchronize the IMU data and the GNSS data. The data transmission module is configured to transmit the synchronized IMU data and GNSS data to the control system end in real time. The IMU data calculation module is configured to calculate a first parameter based on the IMU data, where the first parameter includes a position, a velocity, and a heading angle of a first antenna. The GNSS data calculation module is configured to calculate a second parameter based on the GNSS data, where the second parameter includes the position and the velocity of the first antenna, and a heading angle of a baseline between dual antennas. The LCI calculation module is configured to perform LCI calculation using the first parameter and the second parameter by using an extended Kalman filter algorithm, to determine a position, a velocity, and a heading angle of the transmission tower. The tilt determining module is configured to determine a tilt of the transmission tower based on the heading angle of the transmission tower. In the example, the data synchronization module specifically includes: a signal access unit, configured to connect a GNSS signal and an IMU signal simultaneously to the FPGA board; a decoding unit, configured to decode GPS, BDS, GLONASS, and Galileo from the GNSS signal to obtain time information; a time difference determining unit, configured to determine a time difference between the GNSS signal and the IMU signal that are transmitted to the FPGA board; an IMU signal initial time information synchronization unit, configured to calculate time information of the IMU signal, denoted as IMU signal initial time, based on the decoded time information of GPS, BDS, GLONASS, and Galileo and the time difference; and an IMU signal time information synchronization unit, configured to determine, based on the input to the FPGA board. In the example, the data transmission module specifically includes: a data transmission unit, configured to transmit the synchronized IMU data and GNSS data to the control system end in real time through 4G/5G. In the example, the system further includes: a GNSS system parameter obtaining unit, configured to obtain GNSS system parameters solved by IGS, where the parameters include a precise orbit, a real-time precision clock offset, an ionospheric parameter, a satellite's differential code bias, and an uncalibrated phase delay of a satellite. In the example, the GNSS data calculation module specifically includes: a position and velocity calculation unit, configured to perform RT-PPP position and velocity calculation on the first antenna based on GNSS data of the first antenna and the parameters of the GNSS system solved by the IGS, to obtain an absolute position and velocity of the first antenna under the e frame; a baseline vector determining unit, configured to use the first antenna as a reference station and a second antenna as a rover station to perform ultra-short baseline RTK calculation based on the GNSS data of the first antenna and GNSS data of the second antenna, to obtain a baseline vector between the first antenna and the second antenna; and a heading angle solution unit, configured to convert the baseline vector to a navigation frame and determine a heading angle of the baseline vector in the navigation frame. The method and system for real-time tilt monitoring of a transmission tower provided by the present invention have the following advantages: (1) Positions of the transmission towers can be accurately determined. Thanks to GNSS real-time precise orbit products and PPP technologies, the multi-system GNSS RT-PPP in the present invention can provide real-time centimeter-level positioning, and realize continuous positioning and monitoring, to accurately locate a transmission tower subject to tilting. (2) Attitude of the transmission towers can be accurately determined. The present invention first uses the ultra-short baseline RTK technology to achieve high-accuracy baseline resolution and obtain a precise heading angle of the baseline determined by the two antennas; performs data fusion based on the heading angle and a position and a velocity that are provided by RT-PPP; and uses the LCI technology to overcome the low-cost INS attitude divergence problem and reduce the computation amount. With the real-time dual-antenna heading, PPP, and INS LCI technologies, high-accuracy attitude determining results of hundreds of hertz can be provided, to realize accurate tilt monitoring for the transmission towers. Each example of the present specification is described in a progressive manner, each example focuses on the difference from other examples, and the same and similar parts between the the method disclosed in the examples, the description is relatively simple, and reference can be made to the method description. In this paper, several examples are used for illustration of the principles and implementations of the present invention. The description of the foregoing examples is used to help illustrate the method of the present invention and the core principles thereof. In addition, those of ordinary skill in the art can make various modifications in terms of specific implementations and scope of application in accordance with the teachings of the present invention. In conclusion, the content of the specification shall not be construed as a limitation to the present invention.

Claims

What is claimed is: 1. A method for real-time tilt monitoring of a transmission tower, comprising: obtaining Inertial Measurement Unit (IMU) data collected by an inertial sensor and Global Navigation Satellite System (GNSS) data provided by a dual-antenna GNSS system, wherein both the inertial sensor and the dual-antenna GNSS system are installed on a transmission tower; synchronizing the IMU data and the GNSS data; transmitting the synchronized IMU data and GNSS data to a control system end in real time; calculating, by the control system end, a first parameter based on the IMU data, wherein the first parameter comprises a position, a velocity, and a heading angle of a first antenna; calculating, by the control system end, a second parameter based on the GNSS data, wherein the second parameter comprises the position and the velocity of the first antenna, and a heading angle of a baseline between dual antennas; performing, by using an extended Kalman filter algorithm, Loose Coupled Integration (LCI) calculation using the first parameter calculated from the IMU data and the second parameter calculated from the GNSS data, to determine a position, a velocity, and a heading angle of the transmission tower; and determining a tilt of the transmission tower based on the heading angle of the transmission tower.
2. The method for real-time tilt monitoring of a transmission tower according to claim 1, wherein the synchronizing the IMU data and the GNSS data specifically comprises: connecting a GNSS signal and an IMU signal simultaneously to an FPGA board; decoding GPS, BDS, GLONASS, and Galileo from the GNSS signal to obtain time information; determining a time difference between the GNSS signal and the IMU signal that are transmitted to the FPGA board; calculating time information of the IMU signal, denoted as IMU signal initial time, based on the decoded time information of GPS, BDS, GLONASS, and Galileo and the time difference; and determining, based on the IMU signal initial time and an IMU sampling rate, time information of IMU data to be subsequently input to the FPGA board; wherein the transmitting the synchronized IMU data and GNSS data to a control system end in real time specifically comprises: transmitting the synchronized IMU data and GNSS data to the control system end in real time through 4G/5G; wherein before the calculating a second parameter based on the GNSS data, the method further comprises: obtaining GNSS system parameters solved by International GNSS Service center (IGS), parameter, a satellite's differential code bias, and an uncalibrated phase delay of a satellite, further wherein the calculating a second parameter based on the GNSS data specifically comprises: performing Real-Time Precise Point Positioning (RT-PPP) position and velocity calculation on the first antenna based on GNSS data of the first antenna and the parameters of the GNSS system solved by the IGS, to obtain an absolute position and velocity of the first antenna under an earth centered earth fixed frame; using the first antenna as a reference station and a second antenna as a rover station to perform ultra-short baseline Real-Time Kinematic (RTK) calculation based on the GNSS data of the first antenna and GNSS data of the second antenna, to obtain a baseline vector between the first antenna and the second antenna; and converting the baseline vector to a navigation frame and determining a heading angle of the baseline vector in the navigation frame.
3. A system for real-time tilt monitoring of a transmission tower, comprising: a control system end, an inertial sensor and a dual-antenna GNSS system installed on a transmission tower, an FPGA board, and a data transmission module, wherein the FPGA board comprises a data obtaining module and a data synchronization module; the control system end comprises an IMU data calculation module, a GNSS data calculation module, an LCI calculation module, and a tilt determining module; the data obtaining module is configured to obtain IMU data collected by the inertial sensor and GNSS data provided by the dual-antenna GNSS system; the data synchronization module is configured to synchronize the IMU data and the GNSS data; the data transmission module is configured to transmit the synchronized IMU data and GNSS data to the control system end in real time; the IMU data calculation module is configured to calculate a first parameter based on the IMU data, wherein the first parameter comprises a position, a velocity, and a heading angle of a first antenna; the GNSS data calculation module is configured to calculate a second parameter based on the GNSS data, wherein the second parameter comprises the position and the velocity of the first antenna, and a heading angle of a baseline between dual antennas; the LCI calculation module is configured to perform LCI calculation using the first parameter and the second parameter by using an extended Kalman filter algorithm, to determine a position, a velocity, and a heading angle of the transmission tower; and the tilt determining module is configured to determine a tilt of the transmission tower based on the heading angle of the transmission tower.
4. The system for real-time tilt monitoring of a transmission tower according to claim 3, wherein the data synchronization module specifically comprises: the FPGA board; a decoding unit, configured to decode GPS, BDS, GLONASS, and Galileo from the GNSS signal to obtain time information; a time difference determining unit, configured to determine a time difference between the GNSS signal and the IMU signal that are transmitted to the FPGA board; an IMU signal initial time information synchronization unit, configured to calculate time information of the IMU signal, denoted as IMU signal initial time, based on the decoded time information of GPS, BDS, GLONASS, and Galileo and the time difference; and an IMU signal time information synchronization unit, configured to determine, based on the IMU signal initial time and an IMU sampling rate, time information of IMU data to be subsequently input to the FPGA board; wherein the data transmission module specifically comprises: a data transmission unit, configured to transmit the synchronized IMU data and GNSS data to the control system end in real time through 4G/5G.
5. The system for real-time tilt monitoring of a transmission tower according to claim 3, wherein the system further comprises: a GNSS system parameter obtaining unit, configured to obtain GNSS system parameters solved by IGS, wherein the parameters comprise a precise orbit, a real-time precision clock offset, an ionospheric parameter, a satellite's differential code bias, and an uncalibrated phase delay of a satellite, further wherein the GNSS data calculation module specifically comprises: a position and velocity calculation unit, configured to perform RT-PPP position and velocity calculation on the first antenna based on GNSS data of the first antenna and the parameters of the GNSS system solved by the IGS, to obtain an absolute position and velocity of the first antenna under an earth centered earth fixed frame; a baseline vector determining unit, configured to use the first antenna as a reference station and a second antenna as a rover station to perform ultra-short baseline RTK calculation based on the GNSS data of the first antenna and GNSS data of the second antenna, to obtain a baseline vector between the first antenna and the second antenna; and a heading angle solution unit, configured to convert the baseline vector to a navigation frame and determine a heading angle of the baseline vector in the navigation frame.