A method for three-dimensional measurement of a water turbine rotor based on an accuracy transmission chain

Abstract

The application discloses a kind of water turbine rotor three-dimensional measurement methods based on precision transmission chain, this method first establishes by tracking instrument measurement target ball, photographic survey target ball and local scanning target point is composed of multilevel measurement control network, forms complete precision transmission system.Second, using the measurement mechanism of two-way real-time verification, through the combination of forward precision transmission and reverse precision verification, and the precision transmission verification of adjacent area, ensure the reliability of measurement process.Finally, for the precision anomaly that appears in the measurement process, construct the hierarchical repair strategy based on precision transmission chain, including abnormality determination, hierarchical repair and integrity verification.The method can ensure the high-precision measurement of large-size water turbine rotor geometric features while establishing a complete precision guarantee system, solve the problems of uncontrollable precision transmission and imperfect verification mechanism in traditional measurement methods, and significantly improve the efficiency and reliability of water turbine rotor measurement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic turbine detection, and in particular to a three-dimensional measurement method for a hydraulic turbine rotor based on an accuracy transfer chain. BACKGROUND

[0002] The hydraulic turbine rotor is one of the key components of a hydroelectric generator set, and its geometric size accuracy directly affects the operation efficiency and service life of the generator set. With the development of large-scale and high-efficiency hydroelectric generator sets, the machining accuracy and measurement accuracy of the rotor are increasingly required. Currently, the measurement of the hydraulic turbine rotor mainly faces the following technical problems:

[0003] Firstly, the hydraulic turbine rotor is large in size and has a large curvature change, and the traditional single measurement method cannot achieve comprehensive coverage. For example, although the laser tracker has high measurement accuracy, it is limited by the field of view angle and cannot complete the measurement of all areas of the rotor; the laser scanner can obtain dense surface data, but the measurement accuracy in the independent mode is difficult to guarantee.

[0004] Secondly, the existing geometric size measurement method for the rotor lacks a complete accuracy transfer mechanism. In actual measurement process, multiple measurement means often need to work together, but the accuracy transfer between the measurement systems lacks effective control and verification mechanism, which makes it difficult to guarantee the reliability of the final measurement result. Especially in the partition measurement of large-size rotor, the splicing accuracy problem of adjacent areas is particularly prominent.

[0005] In addition, the accuracy anomaly in the measurement process is difficult to find and repair in time. Due to the lack of systematic accuracy monitoring and verification mechanism, the accuracy problem in the measurement process is often found in the later data processing, which not only increases the rework cost, but also affects the measurement efficiency. Even if the problem is found, the existing technology lacks a targeted repair scheme, and often needs to perform full measurement again.

[0006] In order to solve the above problems, it is urgent to develop a hydraulic turbine rotor surface measurement method which can guarantee the reliable transfer of measurement accuracy, has a complete verification mechanism, and can timely find and repair accuracy problems. SUMMARY

[0007] To solve the current technical problems, the main purpose of the present application is to provide a three-dimensional measurement method for a hydraulic turbine rotor based on an accuracy transfer chain, which realizes the reliable accuracy transfer from high-precision reference to end measurement through the construction of a multi-level measurement control network, and solves the accuracy guarantee problem of large hydraulic turbine rotor geometric size measurement.

[0008] To solve the above technical problems, the technical scheme adopted by the present application is: a three-dimensional measurement method for a hydraulic turbine rotor based on an accuracy transfer chain, comprising the following steps:

[0009] S1, arranging different types of measurement reference on the surface of the water turbine rotor to establish a multi-level measurement control network; wherein the different types of measurement reference include: arranging a tracker measurement target ball, a photogrammetry target ball and a scanning target point on the surface of the water turbine rotor, and the multi-level measurement control network includes a high-precision reference network, a secondary control network and a local measurement network;

[0010] S2, during measurement, a bidirectional real-time verification measurement mechanism is used to ensure the reliability of the measurement data through a combination of forward precision transfer and reverse precision verification, and precision transfer verification of adjacent areas;

[0011] S3, based on the abnormal situation of each level of the precision transfer chain, repair measures are taken, and the repair effect is ensured through verification.

[0012] In S1, the method for establishing a high-precision reference network includes:

[0013] The tracker measurement target ball is fixed on the outer circumferential surface of the water turbine rotor using a magnetic base, each measurement area can observe more than three tracker measurement target balls, the tracker measurement target ball is measured by a laser tracker to obtain accurate spatial coordinates, and a high-precision reference network is established.

[0014] In S1, the method for establishing a secondary control network includes:

[0015] The photogrammetry target ball is fixed on the outer circumferential surface of the water turbine rotor using a magnetic base, the photogrammetry target balls maintain an overlap of 30%-50%, images are collected by a global photogrammetry system, the spatial position of the photogrammetry target ball is calculated in combination with the high-precision reference network, and a reliable measurement control network is formed.

[0016] In S1, the method for establishing a local measurement network includes:

[0017] The entire water turbine rotor is divided into several local measurement areas, at least three scanning target points are arranged in each local measurement area, the scanning target points form effective observation overlap with the surrounding photogrammetry target balls, a handheld laser scanner is used, scanning positioning is realized by recognizing the scanning target points, and dense surface data of the local area of the outer circumferential surface of the rotor is collected.

[0018] In S2, the forward precision transfer process is from high precision to low precision;

[0019] Wherein, the laser tracker first measures the tracker measurement target ball to obtain the highest precision reference, then uses these known high-precision coordinates to calibrate the global photogrammetry system, and then calculates the spatial position of the photogrammetry target ball, and finally the handheld scanner obtains the spatial position of the surface data by recognizing the photogrammetry target ball and the scanning target points on the surface of the rotor.

[0020] In S2, the reverse accuracy verification is from low accuracy back to high accuracy;

[0021] In which, by comparing the deviation of the scanning target point coordinates obtained by the handheld scanner and the photogrammetry target ball coordinates given by the photogrammetry, the scanning accuracy is verified, and then the deviation of the coordinates of the photogrammetry target ball and the tracking instrument measurement target ball coordinates given by the laser tracker is compared to verify the photogrammetry accuracy.

[0022] In S2, the accuracy transfer verification method of adjacent areas includes:

[0023] The overlapping part of the two areas contains a complete accuracy transfer chain node, that is, there are tracking instrument measurement target balls, photogrammetry target balls and scanning target points, and by comparing the consistency of the coordinates of these nodes in the two areas, it is ensured that the accuracy will not be attenuated in the area expansion process.

[0024] In S3, the abnormal situation judgment method based on each level of the accuracy transfer chain includes:

[0025] When the deviation of the laser tracker repeatedly measuring the tracking instrument measurement target ball exceeds the limit, it indicates that the high-precision reference network has a problem;

[0026] When the deviation of the photogrammetry target ball coordinates calculated by photogrammetry and the coordinates given by the laser tracker exceeds the limit, it indicates that the secondary control network link has a problem;

[0027] When the deviation of the scanning target point coordinates obtained by scanning and the coordinates given by the photogrammetry is too large, it indicates that the local measurement network has a problem.

[0028] In S3, the repair measures include:

[0029] Corresponding repair measures are taken for different links of the accuracy transfer chain;

[0030] In which, for the problem of high-precision reference network, the tracking instrument measurement target ball is re-arranged and measured, and the data of the entire transfer chain is updated;

[0031] For the problem of the secondary control network, the photogrammetry target ball is encrypted, the measurement angle is optimized, and the calculation accuracy is improved;

[0032] For the problem of the local measurement network, the scanning parameters are adjusted, the partition range is reduced, and the overlap degree is increased.

[0033] In S3, the verification method after repair includes:

[0034] Including three aspects of reference verification, transfer verification and connection verification;

[0035] In the benchmark verification link, all tracking instrument measurement target balls need to be re-measured to verify whether the deviation from the original coordinates is within ±0.02mm, and to confirm the stability of the network structure;

[0036] In the transmission verification link, the secondary control network is recalculated using the repaired benchmark to verify whether the photogrammetry target ball coordinate solution accuracy meets the requirement of ±0.05mm, and to check the reliability of the network connection;

[0037] In the connection verification link, the edge data of the repaired area and the non-repaired area need to be compared to ensure the smoothness of the transition area, and the surface data splicing accuracy is controlled within ±0.08mm.

[0038] The present application has the following beneficial effects:

[0039] 1. A complete precision transmission system is established. Through the construction of multi-level measurement control network, reliable precision transmission from high-precision benchmark to end measurement is realized, and the precision guarantee problem of large-scale water turbine rotor geometric size measurement is solved.

[0040] 2. A systematic verification mechanism is provided. The two-way real-time verification mechanism not only ensures the reliability of the measurement process, but also discovers precision abnormalities in time, avoiding the defects that problems can only be found in the later stage in traditional methods.

[0041] 3. Precision problems are repaired in time. Based on the hierarchical repair strategy of the precision transmission chain, corresponding repair measures can be taken for precision problems in different links, significantly improving the measurement efficiency.

[0042] 4. The reliability of the measurement data is improved. The complete precision transmission, verification and repair mechanism ensures that the final rotor measurement data has traceable precision guarantee, meeting the measurement needs of the large-scale development of hydroelectric generating sets. BRIEF DESCRIPTION OF DRAWINGS

[0043] The present application will be further described below in conjunction with the drawings and examples.

[0044] Figure 1 The flowchart for implementing the present application.

[0045] Figure 2 The tracking instrument measurement target ball layout schematic diagram.

[0046] Figure 3 The photogrammetry target ball layout schematic diagram.

[0047] Figure 4 The layout schematic diagram of the tracking instrument measurement target ball, the photogrammetry target ball and the scanning target point in adjacent measurement areas. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0049] Referring to Figure 1 A three-dimensional measurement method of a water turbine rotor based on an accuracy transfer chain is shown, which comprises the following steps:

[0050] S1, different types of measurement references are arranged on the surface of the water turbine rotor, a multi-level measurement control network is established, and a complete accuracy transfer network system is formed. Among them, different types of measurement references include: arranging a tracking instrument measurement target ball, a photogrammetry target ball and a scanning target point on the surface of the water turbine rotor, and the multi-level measurement control network includes a high-precision reference network, a secondary control network and a local measurement network. In specific implementation, it is necessary to start from the high-precision reference network, and gradually establish the secondary control network and the local measurement network.

[0051] The method for establishing the high-precision reference network comprises:

[0052] The tracking instrument measurement target ball is fixed on the outer circumferential surface of the water turbine rotor using a magnetic base, more than 3 tracking instrument measurement target balls can be observed in each measurement area at the same time, the tracking instrument measurement target ball is measured by a laser tracker, accurate spatial coordinates are obtained, and a high-precision reference network is established.

[0053] Specifically, referring to Figure 2 , suitable measurement positions are selected on the outer circumferential surface of the rotor, and the tracking instrument measurement target ball is fixed using a magnetic base. According to the size of the rotor, 6-12 target balls are arranged at key positions such as the top and bottom of the circumference to ensure that more than 3 target balls can be observed in each local measurement area at the same time. A laser tracker with a measurement accuracy better than ±0.015 mm is used to complete multi-station measurement of these target balls at 5-8 measurement stations, high-precision spatial coordinate values of the target balls are obtained through least squares adjustment, and the highest precision reference of measurement is established.

[0054] The method for establishing the secondary control network comprises:

[0055] The photogrammetry target ball is fixed on the outer circumferential surface of the water turbine rotor using a magnetic base, the photogrammetry target balls maintain an overlap degree of 30%-50%, images are collected by a global photogrammetry system, the spatial positions of the photogrammetry target balls are calculated in combination with the high-precision reference network, and a reliable measurement control network is formed.

[0056] Specifically, referring to Figure 3The coded photogrammetry target balls are arranged on the outer circumferential surface of the rotor and are also fixed by the magnetic base. The distance between the target balls is controlled to be 200-400 mm, and the observation degree of 30%-50% is ensured between the adjacent target balls. The high-definition industrial camera is used to collect image data of 8-12 stations at different angles. The spatial coordinates of all the photogrammetry target balls are obtained by the bundle adjustment based on the known coordinates of the tracker measurement target balls.

[0057] The method for establishing the local measurement network comprises:

[0058] The whole water turbine rotor is divided into a plurality of local measurement regions, and at least three scanning target points are arranged in each local measurement region. The scanning target points and the surrounding photogrammetry target balls form effective observation overlap. A handheld laser scanner is used to realize scanning positioning by recognizing the scanning target points, and is used to collect dense surface data of the local region of the outer circumferential surface of the rotor.

[0059] Specifically, referring to Figure 4 The whole water turbine rotor is divided into a plurality of local measurement regions. 20-30 reflective sticker target points, i.e. scanning target points, are arranged in each region, and the scanning target points and the surrounding photogrammetry target balls form effective observation overlap. A handheld laser scanner with scanning accuracy better than ±0.03 mm is used to realize scanning positioning by recognizing the scanning target points, and is used to collect dense surface data of the local region of the outer circumferential surface of the rotor.

[0060] S2, during measurement, a bidirectional real-time verification measurement mechanism is adopted, which includes forward accuracy transfer, reverse accuracy verification and accuracy transfer verification of adjacent regions, constitutes a complete accuracy guarantee system and ensures the reliability of the measurement data.

[0061] The forward accuracy transfer process is from high accuracy to low accuracy;

[0062] The laser tracker first measures the tracker measurement target ball to obtain the highest accuracy reference; then, the known high-accuracy coordinates are used to calibrate the global photogrammetry system, and the spatial position of the photogrammetry target ball is solved; finally, the handheld scanner obtains the spatial position of the surface data by recognizing the photogrammetry target ball and the scanning target points on the rotor surface.

[0063] The reverse accuracy verification is from low accuracy back to high accuracy;

[0064] By comparing the deviation of the scanning target point coordinates obtained by the handheld scanner and the photogrammetry target ball coordinates given by the photogrammetry, the scanning accuracy is verified, and by comparing the deviation of the coordinates of the photogrammetry target ball and the coordinates of the tracker measurement target ball given by the laser tracker, the photogrammetry accuracy is verified.

[0065] Specifically, in the end verification link, the target point coordinates obtained by scanning need to be compared with the theoretical target point coordinates given by optical measurement, and the deviation should not exceed ±0.08mm. In the middle verification link, after completing a group of photogrammetric measurement, the tracking instrument measurement target ball coordinates calculated and the coordinates directly measured by the laser tracker are compared, and the deviation should be controlled within ±0.05mm. In the reference verification link, the tracking instrument measurement target ball needs to be measured regularly to ensure that the coordinate stability is within ±0.02mm.

[0066] The accuracy transfer verification method of adjacent areas includes:

[0067] The overlapping part of the two areas should contain a complete accuracy transfer chain node, that is, there should be a tracking instrument measurement target ball, a photogrammetric measurement target ball and a scanning target point, and by comparing the coordinate consistency of these nodes in the two areas, it is ensured that the accuracy will not decay in the area expansion process.

[0068] Specifically, the adjacent measurement areas need to maintain an overlap of 200-300mm, and the overlapping area should contain at least 2 tracking instrument measurement target balls, 4 photogrammetric measurement target balls and 8 scanning target points. The coordinate deviation of the same points in the overlapping area should not exceed ±0.08mm, and the average deviation of the surface data should be controlled within ±0.05mm.

[0069] S3, based on the abnormal situation of each level of the accuracy transfer chain, taking repair measures and ensuring the repair effect through verification, thereby providing a system judgment standard and repair scheme.

[0070] The abnormal situation judgment method based on each level of the accuracy transfer chain includes:

[0071] When the deviation of the laser tracker repeatedly measuring the tracking instrument measurement target ball exceeds the limit, it indicates that the high-precision reference network has a problem.

[0072] Specifically, the laser tracker itself has a coordinate system, and when the deviation of the laser tracker repeatedly measuring the tracking instrument measurement target ball exceeds the limit, it indicates that the high-precision reference network has a problem.

[0073] When the deviation of the photogrammetric measurement target ball coordinates calculated by photogrammetric measurement and the coordinates given by the laser tracker exceeds the limit, it indicates that the secondary control network link has a problem.

[0074] Specifically, since the magnetic bases of the photogrammetric measurement target ball and the tracking instrument measurement target ball are shared, the photogrammetric measurement target ball and the tracking instrument measurement target ball are placed in the same position, therefore, by using the photogrammetric system to scan the photogrammetric measurement target ball and calculating the relative position between the target balls, the result can be compared with the result calculated by the laser tracker.

[0075] When the deviation between the scanning target point coordinates obtained by scanning and the coordinates given by photogrammetry is too large, it indicates that the local measurement network has a problem.

[0076] Specifically, the photogrammetry target ball has mark points on its surface, which can also be measured by the handheld scanner. Therefore, the handheld scanner can also calculate the relative positions of these points. If the deviation from the photogrammetry calculation is too large, there is a problem.

[0077] In this embodiment, in the high-precision reference network link, when the tracking instrument measurement target ball repeated measurement deviation exceeds 0.02 mm, it is determined to be abnormal;

[0078] In this embodiment, in the secondary control network link, when the deviation between the target ball coordinates calculated by photogrammetry and the coordinates given by the tracking instrument exceeds 0.05 mm, it is determined to be abnormal;

[0079] In this embodiment, in the local measurement network link, when the deviation between the scanning target point coordinates obtained by scanning and the coordinates given by photogrammetry exceeds 0.08 mm, it is determined to be abnormal.

[0080] The repair measures include:

[0081] Corresponding repair measures are taken for different links of the precision transfer chain;

[0082] Among them, for the problem of high-precision reference network, the tracking instrument measurement target ball is re-arranged and measured, and the data of the entire transfer chain is updated;

[0083] For the problem of secondary control network, the photogrammetry target ball is encrypted, the measurement angle is optimized, and the calculation accuracy is improved;

[0084] For the problem of local measurement network, the scanning parameters are adjusted, the partition range is reduced, and the overlap degree is increased.

[0085] Specifically, for the problem of high-precision reference network link, the fixing of the magnetic base needs to be checked and adjusted, and the number of tracking instrument measurement target ball stations needs to be increased, for example, 2-3 stations are added based on the original, and if necessary, the tracking instrument measurement target ball is re-arranged and measured. For the problem of secondary control network link, 2-3 photogrammetry target balls need to be added in the precision abnormal area, 2-4 new station images need to be supplemented, the photogrammetry network structure needs to be optimized, and the overall adjustment calculation needs to be performed again. For the problem of the end local measurement network link, the scanning parameters need to be adjusted, for example, the point cloud density is encrypted from the original 0.5 mm to 0.3 mm, the single scanning area is reduced, for example, from 0.5 m x 0.5 m to 0.3 m x 0.3 m, and the area overlap degree is increased, for example, from 30% to 50%.

[0086] The verification method after repair includes:

[0087] The three aspects include benchmark verification, transmission verification and connection verification.

[0088] In the benchmark verification, all the tracking instruments need to measure the target ball again to verify whether the deviation from the original coordinate is within ±0.02mm, and to confirm the stability of the network structure.

[0089] In the transmission verification, the secondary control network is recalculated using the repaired benchmark to verify whether the coordinate calculation accuracy of the photogrammetry target ball meets the requirement of ±0.05mm, and to check the reliability of the network connection.

[0090] In the connection verification, the edge data of the repaired area and the unrepaired area are compared to ensure the smoothness of the transition area, i.e. the curvature is continuous, and the surface data splicing accuracy is controlled within ±0.08mm.

[0091] Through the above steps, the high-precision measurement of the water turbine rotor is realized, and a complete precision transmission system is established. Through the construction of multi-level measurement control network, reliable precision transmission from high-precision benchmark to end measurement is realized, and the precision guarantee problem of large water turbine rotor geometric size measurement is solved. Through the bidirectional real-time verification mechanism, not only the reliability of the measurement process is ensured, but also the precision abnormality can be found in time, avoiding the defect that the problem can only be found in the later stage in the traditional method. The hierarchical repair strategy based on the precision transmission chain can take corresponding repair measures for the precision problems of different links, which significantly improves the measurement efficiency. The complete precision transmission, verification and repair mechanism ensures that the final obtained water turbine rotor data has traceable precision guarantee. This measurement method is especially suitable for surface detection of large water turbine parts, which can efficiently and accurately complete the surface measurement task and significantly improve the measurement efficiency and data reliability.

Claims

1. A three-dimensional measurement method for a turbine rotor based on a precision transmission chain, characterized in that: The following steps are involved: S1. Arrange different types of measurement benchmarks on the surface of the turbine rotor and establish a multi-level measurement control network; wherein the different types of measurement benchmarks include: tracker measurement target spheres, photogrammetry target spheres, and scanning target points arranged on the surface of the turbine rotor; the multi-level measurement control network includes a high-precision benchmark network, a secondary control network, and a local measurement network; S2. During measurement, a two-way real-time verification mechanism is used to ensure the reliability of measurement data by combining forward accuracy transfer and reverse accuracy verification, as well as accuracy transfer verification in adjacent areas; S3. Take corrective measures based on abnormal conditions at each level of the precision delivery chain and ensure the effectiveness of the repairs through verification; In S1, a method for establishing a high-precision reference network includes: fixing a tracker measurement target sphere on the outer circumference of a turbine rotor using a magnetic base, wherein each measurement area can simultaneously observe more than three tracker measurement target spheres, measuring the tracker measurement target spheres using a laser tracker to obtain accurate spatial coordinates, and establishing a high-precision reference network; In S1, the method for establishing a secondary control network includes: using a magnetic base to fix the photogrammetric target spheres on the outer circumference of the turbine rotor, maintaining a 30%-50% overlap between the photogrammetric target spheres, collecting images through a global photogrammetric system, and combining them with a high-precision reference network to calculate the spatial position of the photogrammetric target spheres to form a reliable measurement control network; In S1, the method for establishing a local measurement network includes: dividing the entire turbine rotor into a number of local measurement areas, arranging at least three scanning target points in each local measurement area, forming effective observation overlap between the scanning target points and the surrounding photogrammetry target spheres, using a handheld laser scanner to achieve scanning positioning by identifying the scanning target points, and collecting dense surface data of the local area of ​​the rotor outer circumference; In S2, the forward precision transfer process is from high precision to low precision. The laser tracker first measures the tracker measurement target sphere to obtain the highest precision benchmark. These known high-precision coordinates are then used to calibrate the global photogrammetry system, and the spatial position of the photogrammetry target sphere is calculated. Finally, the handheld scanner obtains the spatial position of the profile data by identifying the photogrammetry target sphere and the scanning target points on the rotor surface. In S2, reverse accuracy verification is to trace back from low accuracy to high accuracy; among them, the scanning accuracy is verified by comparing the deviation between the scanning target point coordinates obtained by the handheld scanner and the photogrammetry target sphere coordinates given by photogrammetry, and then the photogrammetry accuracy is verified by comparing the coordinates of the photogrammetry target sphere with the tracker measurement target sphere coordinate deviation given by the laser tracker.

2. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1, characterized in that: In S2, the accuracy transfer verification method of adjacent areas includes: The overlapping part of the two areas must include the complete precision transfer chain nodes, that is, there must be tracker measurement target sphere, photogrammetry target sphere and scanning target point. By comparing the coordinate consistency of these nodes in the two areas, it is ensured that the accuracy will not be attenuated during the area expansion process.

3. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1, characterized in that: In S3, the abnormal situation determination methods based on each level of the precision delivery chain include: When the deviation of the target sphere measured by the laser tracker when it is repeated exceeds the limit, it indicates that there is a problem with the high-precision reference network; When the deviation between the coordinates of the photogrammetric target sphere solved by photogrammetry and the coordinates given by the laser tracker exceeds the limit, it indicates that there is a problem in the secondary control network link; When the coordinates of the scanned target points obtained by scanning deviate too much from the coordinates given by photogrammetry, it indicates that there is a problem with the local measurement network.

4. The method for three-dimensional measurement of a turbine rotor based on a precision transfer chain according to claim 1, characterized in that: In S3, the fixes include: Take corresponding repair measures for different links in the precision transfer chain; For high-precision benchmark network issues, the target sphere is measured by rearranging and measuring trackers, and the data of the entire transmission chain is updated; For the secondary control network problem, the photogrammetry target sphere is encrypted to optimize the measurement angle and improve the solution accuracy; For local measurement network problems, adjust the scanning parameters, reduce the partition range, and increase the overlap.

5. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1, characterized in that: In S3, the fixed verification methods include: It includes three aspects: benchmark verification, transfer verification and connection verification; During the benchmark verification phase, all tracker target spheres need to be re-measured to verify whether the deviation from the original coordinates is within ±0.02mm, confirming the stability of the network structure. In the transfer verification phase, the repaired benchmark is used to recalculate the secondary control network, verify whether the accuracy of the photogrammetry target sphere coordinate solution meets the requirement of ±0.05mm, and check the reliability of the network connection; During the connection verification phase, it is necessary to compare the edge data of the repaired area and the unrepaired area to ensure the smoothness of the transition area and the accuracy of the surface data splicing is controlled within ±0.08mm.

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