Method and system for positioning shooting terminal in strong electromagnetic environment by fusing RTK (Real-Time Kinematic) anti-interference and attitude calculation

Abstract

The invention provides a method and a system for positioning a shooting terminal in a strong electromagnetic environment by fusing RTK anti-interference and attitude calculation, and belongs to the field of RTK positioning. The problem that self-positioning of equipment is easily interfered by external electromagnetic interference in a strong electromagnetic environment is solved; comprising the following steps: constructing a strapdown inertial navigation system; an RTK multi-path cancellation-double-difference positioning model is constructed, the model integrates multi-path suppression and differential positioning technologies, a direct wave cancellation technology is utilized to eliminate a multi-path interference signal having a fixed delay and amplitude attenuation relationship with a direct wave signal, and real-time differential operation is performed in combination with RTK double-difference positioning. Detecting and correcting cycle slip deviation generated in a signal propagation process by combining a double-difference positioning mode with a height difference method cycle slip recovery strategy, and performing position calculation by using a double-difference observation value; introducing extended Kalman filtering, and fusing the RTK positioning data of the shooting terminal with the attitude sensing data to obtain real-time position information of the shooting terminal; the method is applied to positioning of the shooting terminal in the transformer substation.

Description

Technical Field

[0001] The present invention provides a method and system for positioning a shooting terminal in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, belonging to the technical field of RTK positioning. Background Art

[0002] High-precision positioning technology is currently widely used in various industries, such as automobiles, drones, substations, etc. Common positioning methods include GPS positioning, Beidou positioning, inertial navigation positioning, base station positioning, Bluetooth positioning, etc. In GPS positioning, RTK differential technology can improve positioning accuracy. However, RTK differential technology will also have various problems in actual use due to the diversity of application environments. In response to these problems, some scholars have proposed different methods, such as Chinese patent CN118294994A, which fully considers the deviation problem caused by environmental factors such as the atmosphere and ionosphere during the propagation of satellite signals, and discloses an RTK inertial deep combined carrier phase tracking control method. Drawing on the idea of ​​differential positioning, RTK differential information is introduced to eliminate errors such as ionospheric delay and tropospheric delay to reduce satellite observation errors, which can effectively alleviate the problems of integer ambiguity and cycle slips and improve RTK positioning accuracy; such as Chinese patent CN118311630A, which takes into account that the unmanned aerial vehicle loader has high requirements for positioning accuracy, but when the unmanned aerial vehicle is turning or moving on a rugged road, RTK is affected by atmospheric conditions and cannot quickly and accurately locate the vehicle's posture and speed information, and the attitude solution stability is poor. A high-precision positioning method for an unmanned aerial vehicle loader based on RTK and IMU is proposed, and the installation error angle between the IMU coordinate system and the carrier coordinate system is added to the state vector for filtering estimation to improve the positioning and attitude solution accuracy of the integrated navigation system. In order to solve the multipath effect problem caused by the reflection of signals by multiple buildings on the road in the actual driving environment, Chinese patent CN118348563A discloses a method and system for identifying RTK positioning accuracy, combining vehicle-road perception information and RTK positioning information to determine the positioning accuracy of RTK. In order to solve the multipath effect problem caused by the presence of a large number of obstructions in complex mountainous environments, Chinese patent CN118534497A discloses a multi-source adaptive positioning method and system, which processes GNSS data and base station data through the RTK positioning algorithm in a multi-source heterogeneous sensor fusion enhancement module to obtain more accurate differential positioning information.

[0003] However, the above patents only focus on the indirect interference caused by atmospheric propagation errors or multipath effects when receiving signals from RTK technology itself. However, in strong electromagnetic environments such as substations, high-voltage power equipment is densely distributed, which constitutes significant electromagnetic interference to RTK receivers and inertial sensors. This interference will not only reduce the signal quality of the RTK receiver, causing deviations in positioning data, but also greatly reduce the stability of attitude solution. In addition, buildings and high-voltage power equipment, as large physical obstacles, not only directly block the straight-line propagation path of RTK signals, but also have significant reflection and scattering effects on the signals due to their metal materials and complex structures, resulting in multiple paths for the signals to reach the RTK receiver. These signals overlap and interfere with each other, further reducing the accuracy of RTK positioning.

[0004] In the practice of measuring the spatial attitude of equipment, inertial sensors (IMU) are a commonly used technical means. However, the angular velocity obtained by its gyroscope will have cumulative errors in time, and in a strong electromagnetic environment, the magnetometer is easily disturbed, resulting in inaccurate measurement data and poor stability of attitude solution. Summary of the invention

[0005] In order to solve the problem that the self-positioning of equipment in a strong electromagnetic environment is easily affected by external electromagnetic interference, the present invention proposes a method and system for positioning a shooting terminal in a strong electromagnetic environment that integrates RTK anti-interference and attitude solution, which can enhance the shooting terminal's ability to accurately capture position and attitude data in a strong electromagnetic environment, and improve the accuracy of target positioning in images taken by the shooting terminal in a strong electromagnetic environment.

[0006] The technical solution adopted by the present invention is: a method for positioning a shooting terminal in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, comprising the following steps:

[0007] S1: Build a strapdown inertial navigation system and use it to calculate the attitude data of the shooting terminal in a strong electromagnetic environment;

[0008] S2: Construct an RTK multipath cancellation-double difference positioning model, which integrates multipath suppression and differential positioning technologies. The direct wave cancellation technology is used to eliminate multipath interference signals that have a fixed delay and amplitude attenuation relationship with the direct wave signal. At the same time, the RTK double difference positioning is combined to perform real-time differential operations. The double difference positioning method is combined with the high-difference method cycle slip recovery strategy to detect and correct the cycle slip deviation generated during the signal propagation process. The double difference observation value is used for position solution to obtain the precise position information of the shooting terminal.

[0009] S3: Introduce the extended Kalman filter to fuse the RTK positioning data of the shooting terminal with the attitude perception data to obtain the final real-time position information of the shooting terminal.

[0010] The strapdown inertial navigation system includes a 3-axis gyroscope, a 3-axis angular velocity meter, a 3-axis magnetometer, a barometer and a digital motion processor, and simultaneously measures the data of the attitude, angular velocity, geomagnetic field and air pressure of the shooting terminal.

[0011] The digital motion processor constructs state equations and observation equations to solve and obtain raw data of posture as a state quantity.

[0012] The specific implementation process of using the direct wave cancellation technology in step S2 to eliminate the multipath interference signal that has a fixed delay and amplitude attenuation relationship with the direct wave signal is as follows:

[0013] A multipath canceller is set in the reference channel, and an adaptive algorithm is used to estimate and eliminate the multipath signal, thereby obtaining a purified reference direct wave signal;

[0014] Then, the reference direct wave signal obtained in the previous step is subjected to LMS adaptive filtering in the target channel to suppress direct wave interference.

[0015] The specific implementation process of detecting and correcting the cycle slip deviation generated during signal propagation by combining the double difference positioning method with the high difference method cycle slip recovery strategy in step S2 is as follows:

[0016] Firstly, a discontinuous epoch cycle slip detection method is introduced based on the high-order difference method to pre-process the signal after the direct wave cancellation processing;

[0017] Then, the initial coordinate value of the shooting terminal relative to the satellite is calculated;

[0018] Finally, the observation data of multiple satellites are combined and the current three-dimensional coordinates of the shooting terminal are solved by the weighted least squares method.

[0019] The process of preprocessing the signal after direct wave cancellation processing by introducing the discontinuous epoch cycle slip detection method based on the high-order difference method is as follows:

[0020] The interruption count is performed at the epoch of data loss, assuming that the epoch is t 1 , the recaptured epoch is t 2 , then the unlocking time is Δt = t 2 -t 1 ; Set the sampling interval of the high-order difference method to the calculated unlocking time Δt to ensure equal-interval sampling; interpolate the signal after direct wave cancellation processing, interpolate the carrier observation value with a sampling interval of Δt to a sampling interval of 1s, construct high-sampling rate data, and use the high-order difference method for multiple difference detections.

[0021] The pseudo-range single-point positioning method is used to calculate the initial coordinates of the shooting terminal relative to the satellite.

[0022] The process of data acquisition and processing by the strapdown inertial navigation system is as follows:

[0023] Initialize the system first, then collect the raw data of the gyroscope, angular velocity meter, magnetometer and barometer, perform error compensation on the raw data, and solve the preliminary attitude information through the set proportional error. When the set proportional error is less than 1, solve the initial attitude angle through the angular velocity meter and magnetometer, and then calculate the initial quaternion according to the initial attitude angle; when the set proportional error k≥1, use the angular velocity data of the gyroscope to solve the quaternion differential equation, and use the angular velocity meter and magnetometer to solve the attitude angle as the measurement value; then calculate the process error covariance and the measurement error covariance to obtain the attitude angle of the shooting terminal.

[0024] A shooting terminal positioning system in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, comprising a shooting terminal equipped with a strapdown inertial navigation system and an RTK system, wherein a computer program for a shooting terminal positioning method in a strong electromagnetic environment integrating RTK anti-interference and attitude solution is written into a processor of the shooting terminal.

[0025] The shooting terminal is placed in the substation.

[0026] Compared with the prior art, the present invention has the following beneficial effects: the traditional RTK anti-interference is affected by the cycle slip data, resulting in large positioning errors. RTK has insufficient perception of the device's attitude, only obtains the target's coordinate information, and ignores the spatial attitude information. In comparison, the advantages of the present invention are mainly reflected in the following three aspects:

[0027] (1) Strong anti-interference capability. The RTK multipath cancellation-double difference positioning model proposed in the present invention effectively solves the multipath effect problem of substations by suppressing direct wave signals and alleviating cycle slip detection problems.

[0028] (2) Strong attitude perception capability. The strapdown inertial navigation system in the present invention combines extended Kalman and RTK assisted calibration to simultaneously obtain the position information and attitude information of the target, thereby achieving multi-information acquisition.

[0029] (3) Strong robustness. The positioning and anti-interference method of the substation shooting terminal integrating RTK and spatial attitude solution proposed in the present invention solves the problem of high-precision positioning of RTK equipment in a complex electromagnetic interference environment and is applicable to positioning tasks in any complex environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below in conjunction with the accompanying drawings:

[0031] Figure 1 is an overall flow chart of the method of the present invention;

[0032] Figure 2A schematic diagram of the RTK multipath cancellation-double difference positioning model constructed by the present invention;

[0033] Figure 3 The present invention is a flowchart of strapdown inertial navigation system data processing. DETAILED DESCRIPTION

[0034] like Figures 1 to 3 As shown in FIG, the present invention studies the interference problem of RTK positioning and attitude solution technology in a strong electromagnetic environment. Based on RTK positioning technology and extended Kalman filtering, RTK is combined with an inertial navigation system to propose a terminal positioning method in a strong electromagnetic environment that integrates RTK anti-interference and attitude solution. The method improves the position and posture (coordinate information and attitude information) accuracy of the device by suppressing electromagnetic interference and multipath effects of buildings and equipment in a strong electromagnetic field. The specific implementation process is as follows: Figure 1 As shown, including:

[0035] S1, builds a Strapdown Inertial Navigation System (SINS), using sensors such as a 3-axis gyroscope, 3-axis angular velocity meter, 3-axis magnetometer, and barometer to calculate the device's attitude data.

[0036] S2, build an RTK multipath cancellation-double difference positioning model, which integrates multipath suppression and differential positioning technology, uses direct wave cancellation technology to eliminate the impact of multipath effect, and combines double difference positioning method to further eliminate other error sources and eliminate the multipath effect caused by complex building structures and equipment in the substation.

[0037] S3 introduces the extended Kalman filter to fuse the RTK positioning data with the attitude perception data, and uses a combined inertial navigation method of the strapdown inertial navigation system and RTK assisted calibration to improve the stability and accuracy of attitude solution.

[0038] The strapdown inertial navigation system, RTK antenna and other hardware are installed in the shooting terminal that needs to be positioned, and the computer program of the method is written into the shooting terminal.

[0039] like Figure 2 The figure shows the RTK multipath cancellation-double difference positioning model proposed by the present invention, which is used to eliminate the electromagnetic interference of building reflection and shooting terminal. The model is internally provided with a reference channel, an FIR filter, and a target echo channel, and a multipath canceller is provided in the reference channel.

[0040] The specific implementation steps of this model are as follows:

[0041] S2.1: Construct a direct wave interference suppression algorithm for multipath cancellation. By setting a multipath canceller in the reference channel, an adaptive algorithm is used to estimate and eliminate the multipath signal, thereby obtaining a purified reference direct wave signal. Then, the reference direct wave signal is subjected to minimum mean square error LMS adaptive filtering in the target echo channel to suppress direct wave interference. The specific implementation process is as follows:

[0042] Assuming that the output signal of the reference channel is y(t), and N is the number of multipath signals, then:

[0043]

[0044] Where: s(t) represents the reference direct wave signal, n(t-τ i ) represents different delays τ i and the attenuated multipath leakage signal, α i Indicates the signal amplitude on the corresponding path, n(tt i ') represents the cancellation signal, by adjusting its delay t i ' and amplitude α i To match and eliminate the leakage signal.

[0045] Based on the above results, the minimum mean square error LMS algorithm is used for suppression. In the target echo channel, the calculated reference direct wave signal s(t) is used as the reference signal to perform adaptive filtering on the target echo signal. By iteratively updating the coefficients of the FIR filter, the error between the output signal of the FIR filter and the expected signal is minimized to suppress the direct wave interference.

[0046] S2.2: RTK double difference positioning. Based on multipath cancellation technology, RTK double difference positioning is adopted to suppress the positioning deviation generated during signal propagation through cycle slip detection and repair, thereby improving positioning accuracy. The specific implementation process is as follows:

[0047] (1) First, a discontinuous epoch cycle slip detection method is introduced based on the high-order difference method: interruption counting is performed at the epoch where the data is lost, assuming that the epoch is t 1 , the recaptured epoch is t 2 , then the unlocking time is Δt = t 2 -t 1 ; Set the sampling interval of the high-order difference method to the calculated unlocking time Δt to ensure equal-interval sampling; interpolate the original data, interpolate the carrier observation value with a sampling interval of Δt to a sampling interval of 1s, construct high-sampling rate data, and ensure observation accuracy; use the high-order difference method for 4-difference detection.

[0048] (2) Pseudo-range single-point positioning provides a relatively accurate initial coordinate value for relative positioning, mainly based on the transmission time of the satellite signal and the speed of light to calculate the distance between the shooting terminal (receiver) and the satellite.

[0049] (3) Combining the observation data of multiple satellites, the current three-dimensional coordinates of the shooting terminal are solved by the weighted least squares method.

[0050] Based on the above process, the multipath effect caused by the complex building structure in the substation can be eliminated, the positioning deviation caused by external interference such as clock error and delay in satellite positioning can be suppressed, and the RTK positioning accuracy can be further improved.

[0051] The present invention uses direct wave cancellation technology to eliminate the influence of multipath effects. The multipath canceller identifies and eliminates multipath interference signals that have a fixed delay and amplitude attenuation relationship with the direct wave signal. At the same time, combined with RTK double-difference positioning, real-time differential calculation is performed. For the cycle slip deviation generated during the propagation process, the double-difference positioning method is combined with the high-difference method cycle slip recovery strategy to detect and correct it, and the double-difference observation value is used for position solution to obtain the precise position information of the shooting terminal.

[0052] like Figure 3 As shown in the figure, a strapdown inertial navigation system is formed by a 3-axis gyroscope, a 3-axis angular velocity meter, a 3-axis magnetometer and a barometer. The attitude, angular velocity, geomagnetic field and air pressure data of the shooting terminal are measured at the same time, and the state equation (calculation of attitude angle and velocity) and the observation equation (RTK data and state quantity) are constructed. The sensor data is solved by the digital motion processor (DMP) to obtain the original data of the attitude, such as pitch angle, roll angle and heading angle, as the state quantity; at the same time, the position information provided by the RTK system is received, including longitude and latitude data. The position change is calculated through the RTK data to estimate the attitude as the observation quantity; finally, the real-time attitude of the shooting terminal is estimated through the iterative process of the extended Kalman filter algorithm.

[0053] The process of data acquisition and processing of strapdown inertial navigation system is as follows Figure 3 As shown, the system is initialized first, and then the original data of the gyroscope, angular velocity meter, magnetometer and barometer are collected, and the error compensation is performed on the original data. The preliminary attitude information is solved by the set proportional error. In this embodiment, the proportional error k is set to 1. When k is less than 1, the initial attitude angle is solved by the angular velocity meter and the magnetometer, and then the initial quaternion is calculated according to the initial attitude angle; when k≥1, the quaternion differential equation is solved by the angular velocity data of the gyroscope, and the attitude angle is solved by the angular velocity meter and the magnetometer as the measurement value; then the process error covariance and the measurement error covariance are calculated, and finally the optimal attitude angle is estimated by the Kalman filter attitude fusion.

[0054] The present invention combines RTK positioning technology and extended Kalman filter attitude perception technology. By constructing an RTK multipath cancellation-double difference positioning model, the multipath effect caused by the complex building structure in the substation is effectively suppressed. At the same time, the extended Kalman filter is used to deeply integrate and optimize the positioning and attitude perception data, and the spatial attitude information of the shooting terminal in the substation is further effectively obtained, providing reliable technical support for the precise positioning of substation equipment.

[0055] The invention is installed on a certain intelligent image acquisition terminal, and the terminal is placed in a complex natural environment with strong electromagnetic field and multiple buildings in a substation for application, so that the latitude and longitude information, pitch angle and yaw angle of the terminal itself can be obtained in real time. The horizontal error of the positioning information obtained in real time is measured to be 0.035m, and the vertical error is 0.096m.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for positioning a shooting terminal in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, characterized in that: The following steps are involved: S1: Build a strapdown inertial navigation system and use it to calculate the attitude data of the shooting terminal in a strong electromagnetic environment; S2: Construct an RTK multipath cancellation-double difference positioning model, which integrates multipath suppression and differential positioning technologies. The direct wave cancellation technology is used to eliminate multipath interference signals that have a fixed delay and amplitude attenuation relationship with the direct wave signal. At the same time, the RTK double difference positioning is combined to perform real-time differential operations. The double difference positioning method is combined with the high-difference method cycle slip recovery strategy to detect and correct the cycle slip deviation generated during the signal propagation process. The double difference observation value is used for position solution to obtain the precise position information of the shooting terminal. S3: Introduce the extended Kalman filter to fuse the RTK positioning data of the shooting terminal with the attitude perception data to obtain the final real-time position information of the shooting terminal.

2. According to claim 1, a method for positioning a shooting terminal in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, characterized in that: The strapdown inertial navigation system includes a 3-axis gyroscope, a 3-axis angular velocity meter, a 3-axis magnetometer, a barometer and a digital motion processor, and simultaneously measures the data of the attitude, angular velocity, geomagnetic field and air pressure of the shooting terminal.

3. According to claim 2, a method for positioning a shooting terminal in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, characterized in that: The digital motion processor constructs state equations and observation equations to solve and obtain raw data of posture as a state quantity.

4. According to claim 1, a method for positioning a shooting terminal in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, characterized in that: The specific implementation process of using the direct wave cancellation technology in step S2 to eliminate the multipath interference signal that has a fixed delay and amplitude attenuation relationship with the direct wave signal is as follows: A multipath canceller is set in the reference channel, and an adaptive algorithm is used to estimate and eliminate the multipath signal, thereby obtaining a purified reference direct wave signal; Then, the reference direct wave signal obtained in the previous step is subjected to LMS adaptive filtering in the target channel to suppress direct wave interference.

5. According to claim 4, a method for positioning a shooting terminal in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, characterized in that: The specific implementation process of detecting and correcting the cycle slip deviation generated during signal propagation by using the double difference positioning method combined with the high difference method cycle slip recovery strategy in step S2 is as follows: Firstly, a discontinuous epoch cycle slip detection method is introduced based on the high-order difference method to pre-process the signal after the direct wave cancellation processing; Then, the initial coordinate value of the shooting terminal relative to the satellite is calculated; Finally, the observation data of multiple satellites are combined and the current three-dimensional coordinates of the shooting terminal are solved by the weighted least squares method.

6. According to claim 5, a method for positioning a shooting terminal in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, characterized in that: The process of preprocessing the signal after direct wave cancellation processing by introducing the discontinuous epoch cycle slip detection method based on the high-order difference method is as follows: The interruption count is performed at the epoch of data loss, assuming that the epoch is t 1, the recaptured epoch is t 2, then the unlocking time is Δ t = t 2- t 1; Set the sampling interval of the high-order difference method to the calculated unlocking time Δ t , to ensure equal-interval sampling; interpolate the signal after direct wave cancellation processing, and t The carrier observation values ​​are interpolated to a sampling interval of 1 s to construct high sampling rate data, and multiple difference detections are performed using the high-order difference method.

7. According to claim 5, a method for positioning a shooting terminal in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, characterized in that: The pseudo-range single-point positioning method is used to calculate the initial coordinates of the shooting terminal relative to the satellite.

8. According to claim 2, a method for positioning a shooting terminal in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, characterized in that: The process of data acquisition and processing by the strapdown inertial navigation system is as follows: Initialize the system first, then collect the raw data of the gyroscope, angular velocity meter, magnetometer and barometer, perform error compensation on the raw data, and solve the preliminary attitude information through the set proportional error. When the set proportional error is less than 1, solve the initial attitude angle through the angular velocity meter and magnetometer, and then calculate the initial quaternion according to the initial attitude angle; when the set proportional error k≥1, use the angular velocity data of the gyroscope to solve the quaternion differential equation, and use the angular velocity meter and magnetometer to solve the attitude angle as the measurement value; then calculate the process error covariance and the measurement error covariance to obtain the attitude angle of the shooting terminal.

9. A shooting terminal positioning system in a strong electromagnetic environment integrating RTK anti-interference and attitude solution, characterized in that: It comprises a shooting terminal equipped with a strapdown inertial navigation system and an RTK system, wherein a computer program for a shooting terminal positioning method in a strong electromagnetic environment integrating RTK anti-interference and attitude solution as described in any one of claims 1 to 8 is written into the processor of the shooting terminal.

10. The shooting terminal positioning system in a strong electromagnetic environment integrating RTK anti-interference and attitude solution according to claim 9, characterized in that: The shooting terminal is placed in the substation.

Images