In-pipe detector positioning method, system and storage medium

Abstract

The present invention belongs to the technical field of pipeline leakage positioning, and discloses a method, system and storage medium for positioning an in-pipe detector, including: solving the navigation information of the in-pipe detector at each moment; identifying the motion state of the in-pipe detector at each moment and the corresponding duration; for a section of track between any two adjacent ground markers, setting different speed variables for the motion states of the in-pipe detector contained in the current track, and calculating the end point coordinates of the current track based on the accurate starting point coordinates obtained by the ground marker, the duration of each motion state in the current track and the corresponding speed, and minimizing the difference between the end point coordinates and the accurate end point coordinates as the objective function, using a global optimization algorithm to obtain the optimal estimated speed corresponding to each motion state under the current track, and performing multi-source data fusion with the solved navigation information to obtain corrected navigation information, wherein the position information is the position of the in-pipe detector. The present invention can improve the positioning accuracy of the in-pipe detector.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipeline leakage positioning, and more specifically, relates to a method, system and storage medium for positioning an in-pipe detector. Background Art

[0002] Urban water supply pipelines are critical infrastructure for safeguarding residents' lives and industrial activities. Long-term use of underground pipelines can lead to leakage, so regular pipeline leak detection is necessary. Common pipeline leak detection methods include external detection and internal detection. Compared with external detection, internal detection methods equipped with hydrophones traverse the pipeline under the action of water pressure, allowing them to approach the leak point and collect weak leakage acoustic wave signals, resulting in higher detection accuracy. Due to the limited working space within the pipeline and its isolation from the outside world, internal detectors cannot be equipped with large and precise navigation systems for positioning. Instead, positioning is generally performed using small and lightweight inertial navigation modules, such as MEMS-IMUs.

[0003] However, when the inertial navigation module is operating, errors in the process will accumulate over time, causing the navigation error to gradually increase or even diverge. To improve accuracy, a combined navigation method is generally used to suppress the inertial navigation error by introducing auxiliary correction information. The current classic combined navigation method is to use an inertial navigation module plus an odometer. That is, based on the angular velocity and acceleration obtained by the inertial navigation module, an inertial navigation algorithm is used to calculate the navigation information such as the speed, attitude, and position of the internal detector. The speed information of the internal detector is then calculated using the odometer. The speed information calculated by the odometer is then integrated with the calculated navigation information to obtain more accurate navigation information. However, the internal detector using the odometer is in close contact with the pipe wall like a piston, which can easily cause blockage or deformation of the pipe. In addition, slippage and wear of the odometer tire can also cause large positioning errors. Summary of the Invention

[0004] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a method, system and storage medium for positioning an in-pipe detector, the purpose of which is to improve the positioning accuracy of the in-pipe detector.

[0005] To achieve the above object, according to a first aspect of the present invention, a method for positioning an in-pipe detector is provided, wherein the in-pipe detector includes an inertial navigation module, including:

[0006] S1. Calculating navigation information of the inner detector at each moment based on the angular velocity and acceleration obtained by the inertial navigation module;

[0007] S2. Based on the acceleration, identifying the motion state of the inner detector at each moment along the pipeline's forward direction and the corresponding duration; wherein the motion state includes a linear motion state and a turning state;

[0008] S3. For a segment of the trajectory between any two adjacent ground markers, set different speed variables for each detector motion state included in the current trajectory, where the two adjacent ground markers are used to obtain the accurate start and end coordinates of the current trajectory; calculate the end coordinates of the current trajectory based on the accurate start coordinates, the duration of each motion state in the current trajectory, and the corresponding speed;

[0009] S4. Taking the minimization of the difference between the calculated endpoint coordinates and the accurate endpoint coordinates as the objective function, a global optimization algorithm is used to obtain the optimal estimated value of the speed corresponding to each motion state under the current trajectory, and the optimal estimated value of the speed is fused with the navigation information through multi-source data to obtain the corrected navigation information; wherein the position information in the corrected navigation information is the position information of the internal detector.

[0010] Furthermore, S3 also includes:

[0011] The method further includes setting corresponding yaw angle variables for each linear motion state included in the current trajectory; and calculating the end point coordinates of the current trajectory based on the yaw angles corresponding to each linear motion state;

[0012] In S4, when the global optimization algorithm is used to solve the objective function, it also includes obtaining the optimal estimated value of the yaw angle corresponding to each linear motion state under the current trajectory, and performing multi-source data fusion on the optimal estimated value of the yaw angle and the navigation information to obtain corrected navigation information.

[0013] Furthermore, the inner detector motion states contained in the current trajectory are set as follows: linear motion state 1, turning state 1, linear motion state 2, turning state 2, ..., linear motion state n-1, turning state n-1, linear motion state n; the velocity variables corresponding to each state are v1, v1′, v2, v2′, ..., v n-1 , v′ n-1 , v n , the corresponding durations are t1, t1′, t2, t2′, …, t n-1 , t′ n-1 , t n ; and the yaw angles corresponding to each linear motion state are: The exact starting coordinates of the current segment trajectory obtained by two adjacent ground markers are (X start , Y start ), the exact end point coordinate is (X end , Y end ), the coordinates of the end point of the current trajectory are calculated as follows:

[0014]

[0015] in, The coordinates of the end point to be calculated.

[0016] Furthermore, the objective function is:

[0017]

[0018] Wherein, fun is the objective function.

[0019] Furthermore, S3 also includes:

[0020] The method further includes setting corresponding yaw angle variables and pitch angle variables for each linear motion state included in the current trajectory; and calculating the end point coordinates of the current trajectory based on the yaw angles and pitch angles corresponding to each linear motion state;

[0021] In S4, when the global optimization algorithm is used to solve the objective function, it also includes obtaining the optimal estimated value of the yaw angle and the optimal estimated value of the pitch angle corresponding to each linear motion state under the current trajectory, and performing multi-source data fusion of the optimal estimated value of the yaw angle, the optimal estimated value of the pitch angle and the navigation information to obtain corrected navigation information.

[0022] Furthermore, the inner detector motion states contained in the current trajectory are set as follows: linear motion state 1, turning state 1, linear motion state 2, turning state 2, ..., linear motion state n-1, turning state n-1, linear motion state n; the velocity variables corresponding to each state are v1, v1′, v2, v2′, ..., v n-1 , v′ n-1 , v n , the corresponding durations are t1, t1′, t2, t2′, …, t n-1 , t′ n-1 , t n ; and the yaw angles corresponding to each linear motion state are: The pitch angles are: α1, α2, ..., α n-1 , α n ; The accurate starting coordinates of the current segment trajectory obtained by two adjacent ground markers are (X start , Y start , Z start ), the exact end point coordinate is (X end , Y end , Z end ), the coordinates of the end point of the current trajectory are calculated as follows:

[0023]

[0024] in, is the calculated end point coordinate.

[0025] Furthermore, in S2, based on the acceleration, a support vector machine algorithm is used to identify the motion state of the inner detector at each moment along the pipeline forward direction and the corresponding duration;

[0026] In S1, based on the angular velocity and acceleration obtained by the inertial navigation module, an inertial navigation algorithm is used to calculate the navigation information of the inner detector at each moment.

[0027] Furthermore, in S4, an error state Kalman filter algorithm is used to perform the multi-source data fusion to obtain corrected navigation information.

[0028] According to a second aspect of the present invention, there is provided an in-pipe detector positioning system comprising a computer-readable storage medium and a processor;

[0029] The computer-readable storage medium is used to store executable instructions;

[0030] The processor is used to read the executable instructions stored in the computer-readable storage medium to execute the in-pipe detector positioning method described in any one of the first aspects.

[0031] According to a second aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored. When the program is executed by a processor, the method for positioning an in-pipe detector as described in any one of the first aspects is implemented.

[0032] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0033] (1) The in-pipe detector positioning method provided by the present invention identifies the motion state of the in-pipe detector at each moment and the corresponding duration. For a section of track between any two adjacent ground markers, based on the accurate starting coordinates and end coordinates of the section of track obtained by the ground marker, the accurate starting coordinates are used as the starting point of the section of track. Based on the accurate starting coordinates, the duration of different motion states in the section of track and the corresponding speed, the end coordinates corresponding to the section of track can be obtained. The objective function is to minimize the difference between the calculated end coordinates and the accurate end coordinate positions. By using a global optimization algorithm, the optimal estimated value of the speed corresponding to each motion state under the current track can be obtained; that is, the method of calculating the pseudo-measurement value of the speed of the in-pipe detector of the present invention does not need to rely on other sensors, and does not need to calculate the speed information of the in-pipe detector by setting an odometer, thereby avoiding the defects of the in-pipe detector using an odometer. By fusing the optimal speed estimate with the navigation information solved by the inertial navigation module, the accumulated error of the inertial navigation can be corrected, and the positioning accuracy of the in-pipe detector can be improved. Experiments have also proved that the method of the present invention has high positioning accuracy.

[0034] Furthermore, the method of the present invention has no requirements on the pipeline environment, can be applied to a variety of scenarios, and has strong versatility.

[0035] (2) Furthermore, by adding the estimation of the yaw angle in the attitude information, the accuracy of the calculation of the internal detector position information can be further improved.

[0036] (3) Furthermore, the method of the present invention is also applicable to solving three-dimensional positioning problems, that is, based on the accurate three-dimensional starting point coordinates and end point coordinates of the current segment trajectory obtained by two adjacent ground markers, and the motion state of the internal detector contained in the current trajectory, the yaw angle and pitch angle in the speed and attitude information at each moment are simultaneously optimally estimated. By fusing the estimated guidance information with the initially solved guidance information, the accumulated inertial navigation error can be corrected and the positioning accuracy of the internal detector can be improved.

[0037] (4) As a preference, the error state Kalman filter algorithm is used to fuse the optimal estimate with the navigation information initially solved, which can reduce the linearization error, improve the accuracy of the corrected navigation information, and further improve the positioning accuracy of the internal detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a flow chart of a method for positioning an in-pipe detector in an embodiment of the present invention.

[0039] Figure 2 Schematic diagram of a method for positioning an in-pipe detector in an embodiment of the present invention.

[0040] Figure 3 Schematic diagram of the inertial positioning system for in-pipeline detection.

[0041] Figure 4 Schematic diagram of a current running trajectory of the internal detector in an embodiment of the present invention.

[0042] Figure 5 This is an experimental roadmap in an embodiment of the present invention.

[0043] Figure 6 This is the raw data collected by the inertial navigation module in the embodiment of the present invention.

[0044] Figure 7 1 is a positioning trajectory diagram obtained under different experimental conditions in the embodiment of the present invention.

[0045] Figure 8(a) shows the trajectory error when there is no velocity measurement information; Figure 8(b) shows the trajectory error when there is velocity measurement information. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0047] In the present invention, the terms "first", "second", etc. in the present invention and the accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0048] Example 1

[0049] like Figure 1-Figure 3 As shown, the working process of the existing internal detection method equipped with a hydrophone is as follows: the internal detector drifts with the water in the pipeline, wherein the internal detector includes a hydrophone, an inertial navigation module, a high-speed SD card and a power supply, etc.; the hydrophone collects the acoustic wave signal and the ground marker signal along the way, which can assist in positioning while detecting the leak, wherein the ground marker is set at intervals along the pipeline to provide accurate position information of the reference point; the inertial navigation module (generally using MEMS-IMU) is used to obtain the angular velocity and acceleration data (i.e., raw data) of the internal detector at each moment, and the navigation information of the internal detector (including the speed, attitude information and position at each moment) is calculated by the inertial navigation algorithm. In an embodiment of the present invention, a ground marker equipped with an RTK module is set every 2 kilometers. When the RTK module is working, it simultaneously obtains the positioning information of the navigation satellite and the signal base station, and realizes centimeter-level positioning through differential decomposition. After the detection is completed, the internal detector is recovered for offline analysis, and the host computer reads the data in the SD card of the internal detector, analyzes the pipeline leakage condition offline and locates the leakage point.

[0050] Considering that the errors of the inertial navigation module accumulate rapidly over time, it is necessary to introduce external measurement information to correct the navigation information to achieve the target accuracy. However, using an odometer to obtain external measurement information also brings the risk of jamming, positioning errors, and application limitations. The embodiment of the present invention provides a new in-pipe detector positioning method, which mainly includes:

[0051] S1. Based on the angular velocity and acceleration data obtained by the inertial navigation module, an inertial navigation algorithm is used to calculate the navigation information of the inner detector at each moment, wherein the navigation information includes speed, attitude information and position information.

[0052] S2. Based on the acceleration data output by the inertial navigation module, identify the motion state of the inner detector at each moment and the corresponding duration. The motion state includes a stationary state, a linear motion state, and a turning state. The stationary state corresponds to the inner detector at the starting position and the end position of the pipeline. In this embodiment of the present invention, a support vector machine algorithm is used to identify the motion state of the inner detector at each moment based on the acceleration data output by the inertial navigation module. In other embodiments, other machine learning algorithms may also be used.

[0053] S3. For a segment of track between any two adjacent ground markers, set different velocity variables for the motion states of the internal detectors contained in the track, and use the velocity variables as unknown quantities; wherein the two adjacent ground markers are used to obtain the accurate starting and ending coordinates of the segment of track respectively; based on the accurate starting coordinates, the duration of different motion states within the segment of track, and the corresponding speeds, calculate the corresponding ending coordinates of the segment of track;

[0054] S4. Taking the minimum difference between the calculated endpoint coordinates and the accurate endpoint coordinate position as the objective function, a global optimization algorithm is used to obtain the optimal estimated value of the speed corresponding to each motion state under the current trajectory; the optimal estimated value is integrated with the navigation information in S1 to obtain the corrected navigation information; wherein, the position information in the corrected navigation information is the position information of the internal detector, thereby realizing the precise positioning of the pipeline leakage point.

[0055] As a further design of the present invention, S3 also includes setting a corresponding yaw angle for each linear motion state contained in the trajectory, treating the corresponding yaw angle as an unknown quantity, and calculating the corresponding end point coordinates of the trajectory based on the accurate starting point coordinates and the corresponding speed and yaw angle of the duration of different motion states within the trajectory. Correspondingly, in S4, with the objective function of minimizing the difference between the calculated end point coordinates and the accurate end point coordinate position, a global optimization algorithm is used to simultaneously obtain the optimal estimated speed and yaw angle corresponding to each motion state in the current trajectory; the optimal estimated speed and yaw angle are fused with the navigation information in S1 to obtain corrected navigation information; wherein the position information in the corrected navigation information is the position information of the internal detector.

[0056] Assume that for a section of track between any two adjacent ground markers, along the pipeline forward direction, the motion states of the internal detector contained in the track are: stationary state, linear motion state 1, turning state 1, linear motion state 2, turning state 2, ..., linear motion state n-1, turning state n-1, linear motion state n, stationary state; the speed variables corresponding to each state are 0, v1, v1′, v2, v2′, ..., v n-1 , v′n-1 , v n , 0, the corresponding durations are t0, t1, t1′, t2, t2′, …, t n-1 , t′ n-1 , t n , t0′; and the yaw angle corresponding to each linear motion state is: The exact starting coordinates of the current segment trajectory obtained by two adjacent ground markers are (X start , Y start ) and the end point coordinates (X end , Y end ). When calculating the coordinates of the end point corresponding to the current segment of the trajectory, in the embodiment of the present invention, considering that the displacement of each turning state is much smaller than the displacement of the two adjacent linear motion states, the displacement of each turning state is evenly distributed to the straight line segments corresponding to the two adjacent linear motion states. In this way, the coordinates of the end point corresponding to the current segment of the trajectory are The calculation formula is:

[0057]

[0058] Correspondingly, in S4, the objective function fun constructed by the embodiment of the present invention is:

[0059]

[0060] by Figure 4 The trajectory shown is used as the current trajectory. The motion states of the internal detector contained in the trajectory are: static state, linear motion state 1, turning state 1, linear motion state 2, turning state 2, linear motion state 3, static state; the velocity variables corresponding to each state are 0, v1, v′1, v2, v′2, v3, 0, and the corresponding durations are t0, t1, t′1, t2, t′2, t3, t′0; and the yaw angles corresponding to each linear motion state are: The end point coordinates corresponding to the current segment trajectory are The calculation formula is:

[0061]

[0062] It should be noted that if the estimation of the yaw angle is not included, the calculation formula of the end point coordinates corresponding to the current segment trajectory uses the yaw angle in the attitude information calculated in S1 for calculation.

[0063] Furthermore, it also includes optimally estimating the pitch angle in the S1 attitude information, fusing the optimal estimated values ​​of the speed, yaw angle and pitch angle with the navigation information in S1 to obtain corrected navigation information.

[0064] Specifically, the velocity, yaw angle, and pitch angle are optimally estimated simultaneously, including:

[0065] The pitch angles corresponding to the linear motion states of the current trajectory are set as follows: α1, α2, ..., α n-1 , α n ; The accurate starting coordinates of the current segment trajectory obtained by two adjacent ground markers are (X start , Y start , Z start ) and the end point coordinates (X end , Y end , Z end ), then the end point coordinates of the current trajectory are The corresponding calculation formula is:

[0066]

[0067]

[0068] Correspondingly, in S4, the constructed objective function fun is:

[0069]

[0070] By solving the objective function using a global optimization algorithm, the optimal estimated values ​​of the velocity, yaw angle, and pitch angle can be obtained.

[0071] In an embodiment of the present invention, the Globalsearch algorithm in the global optimization algorithm is used to solve the objective function to obtain the globally optimal speed estimate, yaw angle or pitch angle estimate. When using this algorithm for solving, it is necessary to input the initial value of the unknown variable, the upper and lower limits, and the objective function. Considering that most underground pipelines are straight lines, the speed of the internal detector does not change much during steady-state operation. Therefore, the average speed of long-distance straight pipelines can be used as the initial value of each unknown speed in the algorithm. The method of the present invention is also applicable to the correction of the positioning of the internal detector equipped with an odometer. For example, the average speed in each section of the motion state is calculated by the odometer and used as the initial value of the corresponding unknown speed. The upper and lower limits can be reasonably set near the initial value.

[0072] In other embodiments, other global optimization algorithms may also be selected for solving.

[0073] The estimated optimal value and the navigation information of the inner detector at each moment calculated in S1 are fused using an error state Kalman filter algorithm to obtain corrected navigation information, namely, corrected velocity, attitude, and position information. The corrected position information is the position information of the inner detector. In other embodiments, other relevant multi-source data fusion algorithms such as extended Kalman filtering may also be used.

[0074] In order to verify the effect of the positioning correction method proposed in the embodiment of the present invention, a vehicle-mounted simulation experiment was designed. Vehicle road positioning is very similar to pipeline positioning. The main difference is that the former is on the ground and the latter is underground. Road vehicle positioning data can effectively simulate pipeline positioning scenarios, and it is convenient to use common surveying and mapping methods to accurately measure the coordinates and shape of the experimental route to evaluate its error level. During the experiment, the internal detector is fixed in the vehicle and the RTK device is fixed outside the vehicle. The experimental route is 700 meters long and includes 3 straight segments and 2 turns. The experimental route is as follows: Figure 5 shown.

[0075] The parameters of the inertial navigation chip used in the internal detector are shown in Table 1.

[0076] Table 1 Inertial navigation chip parameters

[0077]

[0078] In Table 1, hr represents hour, and ug represents one thousandth of gravity acceleration (microgravity acceleration).

[0079] The real-time dynamic measurement accuracy of RTK equipment is ±(8mm+1×10 -6 D), where D represents the measured distance, and the sampling result of the device is used as the true reference value of the trajectory.

[0080] During the experiment, the MEMS-IMU sampling frequency was 50Hz, and the RTK device sampling frequency was 1Hz. After the system was started, it was kept still for 30 seconds to complete the system warm-up. After reaching the end point, it was kept still for another 15 seconds. The raw data sampled by the accelerometer and gyroscope are as follows: Figure 6 The output of a high-precision RTK device is used as the reference true value in data analysis, and its positioning accuracy is at the centimeter level. The difference between the solution result of the positioning method proposed in the embodiment of the present invention and the reference position can be used as a criterion to evaluate the effectiveness of the positioning method.

[0081] The positioning trajectory is calculated as Figure 7As shown, the red track is the reference true value, and the green track is the control group of the traditional method of inertial navigation plus odometer combined navigation. In the embodiment of the present invention, two groups of vehicle verification experiments are set up. The first group of experiments applies the improved positioning algorithm of the present invention in the absence of external speed measurement information to simulate the situation without odometer. The results are shown in Figure 2. Figure 7 The second set of experiments used the speed displayed on the vehicle dashboard as external measurement information and applied the improved positioning algorithm of the present invention to simulate the situation where there is an odometer. The results are shown in the figure below. Figure 7 Shown in purple.

[0082] In the absence of external speed measurement information, the absolute trajectory error of the positioning method proposed by the present invention is 9.1 meters, and the positioning accuracy is 1.3%, as shown in Figure 8(a). The odometer output is simulated using the vehicle dashboard speed data, and the positioning method proposed by the present invention is used on this basis. The trajectory error obtained is shown in Figure 8(b). The absolute trajectory error before correction was 30.4 meters, and after correction it was 8 meters, and the positioning effect was improved by 73.73%. The experimental results show that the method of the present invention can obtain a speed estimate whose error does not accumulate over time without an odometer, thereby achieving higher-precision positioning. At the same time, for an internal detector equipped with an odometer, the method of the present invention can also effectively correct its trajectory error.

[0083] The in-pipe detector positioning method provided by the present invention identifies the motion state and corresponding duration of the in-pipe detector at each moment. For a section of track between any two adjacent ground markers, based on the accurate starting point coordinates and end point coordinates of the section of track obtained by the ground marker, the accurate starting point coordinates are used as the starting point of the section of track. Based on the accurate starting point coordinates, the durations of different motion states in the section of track and the corresponding speeds, the end point coordinates corresponding to the section of track can be obtained. The objective function is to minimize the difference between the calculated end point coordinates and the accurate end point coordinate positions. A global optimization algorithm is used to obtain the optimal estimate of the speed corresponding to each motion state under the current track. That is, the method of calculating the pseudo-measurement value of the speed of the in-pipe detector according to the present invention does not need to rely on other sensors, and does not need to calculate the speed information of the in-pipe detector by setting an odometer, thereby avoiding the defects of the in-pipe detector using an odometer. By fusing the optimal speed estimate with the navigation information calculated by the inertial navigation module, the inertial navigation accumulated error can be corrected, and the positioning accuracy of the inertial detector can be improved. Experiments have also proved that the method of the present invention has high positioning accuracy.

[0084] Furthermore, the method of the present invention has no requirements on the pipeline environment, can be applied to a variety of scenarios, and has strong versatility.

[0085] Example 2

[0086] An embodiment of the present invention provides an in-pipe detector positioning system, characterized by comprising a computer-readable storage medium and a processor;

[0087] The computer-readable storage medium is used to store executable instructions;

[0088] The processor is configured to read the executable instructions stored in the computer-readable storage medium to execute the in-pipe detector positioning method in Example 1.

[0089] The relevant technical solutions are described in Example 1 and will not be repeated here.

[0090] Example 3

[0091] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the in-pipe detector positioning method as in Example 1. For related technical solutions, see the description in Example 1 and will not be repeated here.

[0092] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for positioning an in-pipe detector, wherein the in-pipe detector includes an inertial navigation module, characterized in that: include: S1. Calculating navigation information of the inner detector at each moment based on the angular velocity and acceleration obtained by the inertial navigation module; S2. Based on the acceleration, identifying the motion state of the inner detector at each moment along the pipeline's forward direction and the corresponding duration; wherein the motion state includes a linear motion state and a turning state; S3. For a segment of the trajectory between any two adjacent ground markers, set different speed variables for each detector motion state included in the current trajectory, where the two adjacent ground markers are used to obtain the accurate start and end coordinates of the current trajectory; calculate the end coordinates of the current trajectory based on the accurate start coordinates, the duration of each motion state in the current trajectory, and the corresponding speed; S4. Taking the minimization of the difference between the calculated endpoint coordinates and the accurate endpoint coordinates as the objective function, a global optimization algorithm is used to obtain the optimal estimated value of the speed corresponding to each motion state under the current trajectory, and the optimal estimated value of the speed is fused with the navigation information through multi-source data to obtain the corrected navigation information; wherein the position information in the corrected navigation information is the position information of the internal detector.

2. The method for positioning an in-pipe detector according to claim 1, wherein: S3 also includes: The method further includes setting corresponding yaw angle variables for each linear motion state included in the current trajectory; and calculating the end point coordinates of the current trajectory based on the yaw angles corresponding to each linear motion state; In S4, when the global optimization algorithm is used to solve the objective function, it also includes obtaining the optimal estimated value of the yaw angle corresponding to each linear motion state under the current trajectory, and performing multi-source data fusion on the optimal estimated value of the yaw angle and the navigation information to obtain corrected navigation information.

3. The method for positioning an in-pipe detector according to claim 2, wherein: The inner detector motion states contained in the current trajectory are set as follows: linear motion state 1, turning state 1, linear motion state 2, turning state 2, ..., linear motion state n-1, turning state n-1, linear motion state n; the velocity variables corresponding to each state are v1, v′1, v2, v′2, ..., v n-1 , v′ n-1 , v n , the corresponding durations are t1, t′1, t2, t′2, …, t n-1 , t′ n-1 , t n ; and the yaw angles corresponding to each linear motion state are: The exact starting coordinates of the current segment trajectory obtained by two adjacent ground markers are (X start , Y start ), the exact end point coordinate is (X end , Y end ), the coordinates of the end point of the current trajectory are calculated as follows: in, is the calculated end point coordinate.

4. The method for positioning an in-pipe detector according to claim 3, wherein: The objective function is: Wherein, fun is the objective function.

5. The method for positioning an in-pipe detector according to claim 1, wherein: S3 also includes: The method further includes setting corresponding yaw angle variables and pitch angle variables for each linear motion state included in the current trajectory; and calculating the end point coordinates of the current trajectory based on the yaw angles and pitch angles corresponding to each linear motion state; In S4, when the global optimization algorithm is used to solve the objective function, it also includes obtaining the optimal estimated value of the yaw angle and the optimal estimated value of the pitch angle corresponding to each linear motion state under the current trajectory, and performing multi-source data fusion of the optimal estimated value of the yaw angle, the optimal estimated value of the pitch angle and the navigation information to obtain corrected navigation information.

6. The method for positioning an in-pipe detector according to claim 5, wherein: The inner detector motion states contained in the current trajectory are set as follows: linear motion state 1, turning state 1, linear motion state 2, turning state 2, ..., linear motion state n-1, turning state n-1, linear motion state n; the speed variables corresponding to each state are v1, v1 ′ ,v2,v2 ′ ,…,v n-1 , v ′ n-1 , v n , the corresponding durations are t1, t1 ′ , t2, t2 ′ ,…,t n-1 , t ′ n-1 , t n ; and the yaw angles corresponding to each linear motion state are: The pitch angles are: α1, α2, ..., α n-1 , α n ; The accurate starting coordinates of the current segment trajectory obtained by two adjacent ground markers are (X start , Y start , Z start ), the exact end point coordinate is (X end , Y end , Z end ), the coordinates of the end point of the current trajectory are calculated as follows: in, is the calculated end point coordinate.

7. The method for positioning an in-pipe detector according to any one of claims 1 to 6, characterized in that: In S2, based on the acceleration, a support vector machine algorithm is used to identify the motion state of the inner detector at each moment along the pipeline forward direction and the corresponding duration; In S1, based on the angular velocity and acceleration obtained by the inertial navigation module, an inertial navigation algorithm is used to calculate the navigation information of the inner detector at each moment.

8. The method for positioning an in-pipe detector according to any one of claims 1 to 6, characterized in that: In S4, an error state Kalman filter algorithm is used to fuse the multi-source data to obtain corrected navigation information.

9. An in-pipe detector positioning system, characterized in that: comprising a computer-readable storage medium and a processor; The computer-readable storage medium is used to store executable instructions; The processor is configured to read the executable instructions stored in the computer-readable storage medium to execute the in-pipe detector positioning method according to any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method for positioning an in-pipe detector according to any one of claims 1 to 8 is implemented.

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