BIM-based automatic lofting system for site surveying

Abstract

The present application relates to the field of building surveying technology, in particular to a field surveying and mapping automatic lofting system based on BIM. The present application selects effective sight points of candidate station sites based on the space occlusion of BIM model and the geometric constraints of laser observation; selects reflection-qualified station sites based on the coverage scale of effective sight points; determines the positioning accuracy degradation based on the positioning accuracy attenuation amplitude of reflection-qualified station sites in the single-point missing state of any field reference point missing in the simulated lofting area relative to the positioning accuracy in the full set state; selects anti-occlusion station sites among the reflection-qualified station sites; determines the preferred index based on the horizontal rotation span of the anti-occlusion station sites covering the effective sight points and the positioning accuracy degradation; and performs surveying and mapping lofting. The present application integrates BIM space analysis and single-point missing simulation, quantifies reflection quality and configuration degradation, selects high-redundancy anti-occlusion station sites, and improves the reliability of surveying and mapping lofting.

Description

Technical Field

[0001] This invention relates to the field of architectural surveying technology, and more specifically to a BIM-based automatic on-site surveying and layout system. Background Technology

[0002] With the widespread adoption of Building Information Modeling (BIM) technology, total station automatic layout systems have become a key tool for improving surveying efficiency on construction sites. These systems typically calculate station coordinates automatically based on BIM design data and drive servo motors to aim at the site prism for layout.

[0003] Existing technology, patent document CN116465374A, discloses a BIM-based building surveying and layout method. Specifically, it uses a total station to automatically extract known control points for station setup and orientation, and a steering device to automatically track a manually held prism, thereby achieving layout and improving the continuity of spatial scanning within the layout area. However, in complex actual construction sites, control points used for re-intersection positioning are often randomly obstructed by factors such as personnel movement, equipment movement, and material stacking. Since the accuracy of re-intersection positioning is highly dependent on the spatial geometry of the control points, if the station location has excessive geometric dependence on a specific control point, once that point is temporarily obstructed, the geometry of the remaining control points will deteriorate sharply, leading to amplified positioning errors and reducing the reliability of automatic on-site surveying and layout. Summary of the Invention

[0004] To address the technical problem of poor positioning accuracy caused by the over-reliance on specific control points when total stations encounter random obstruction at construction sites, this invention aims to provide a BIM-based automatic on-site surveying and layout system. The specific technical solution adopted is as follows: This invention proposes a BIM-based automatic on-site surveying and layout system, the system comprising: The data acquisition module is used to acquire several points to be laid out in the area to be laid out and several candidate site locations in the BIM model of the area. The reflection quality assessment module is used to screen effective line-of-sight points for each candidate site from the points to be laid out based on the spatial occlusion of the BIM model and the geometric constraints of laser observation; and to select qualified reflection sites based on the coverage scale of the effective line-of-sight points. The anti-occlusion stability assessment module is used to determine the positioning accuracy degradation of each qualified reflection site based on the single-point missing state of the simulated area to be laid out, relative to the full set state of all simulated field reference points, and to select the anti-occlusion sites among the qualified reflection sites. The layout optimization module is used to determine the optimal index of each anti-obstruction site based on the horizontal rotation span of each anti-obstruction site covering its effective line of sight and the degree of positioning accuracy degradation, and to perform surveying and layout.

[0005] Furthermore, the step of selecting effective viewpoints for each candidate site from the points to be staked out includes: Obtain the normal vector of the reflection surface at each point to be laid out; The instrument viewpoint for each candidate instrument site is generated based on the preset instrument installation height. For each candidate site, a valid line of sight to the candidate site is selected from all the points to be laid out; the line segment connecting the valid line of sight to the instrument viewpoint of the candidate site does not intersect with the building components in the BIM model, the length of the line segment is less than the preset maximum measurement distance, and the angle between the vector of the valid line of sight pointing to the instrument viewpoint of the candidate site and the normal vector of the reflecting surface is less than the preset limit observation tilt angle.

[0006] Further, determining the positioning accuracy degradation degree of each qualified reflection station includes: Obtain several field reference points for the area to be laid out; for each qualified reflection station, determine the initial set of visible reference points based on the positional distribution of the qualified reflection station and the field reference points; A design matrix for qualified reflection equipment sites is constructed based on an initial set of visible reference points. The elements in each row of the design matrix are the ratios of the difference in the horizontal coordinates and the difference in the vertical coordinates between the qualified reflection equipment site and the corresponding field reference point to the horizontal projection distance between the two points. The inverse matrix of the Gram matrix of the design matrix is ​​calculated using the least squares method, and the square root of the sum of the main diagonal elements of the inverse matrix is ​​used as the reference level accuracy of the qualified reflection design site. The field reference points are removed sequentially from the initial set of visible reference points for iterative updates to obtain the set of visible reference points for each iteration, and the design matrix for that iteration is constructed. The square root of the sum of the main diagonal elements of the inverse of the Gram matrix of the design matrix for each iteration is taken as the degradation level precision for that iteration. The maximum value among all iterations of the deterioration level accuracy is selected and recorded as the deterioration limit level accuracy of the reflective qualified equipment station; the ratio of the difference between the deterioration limit level accuracy and the reference level accuracy to the reference level accuracy is taken as the positioning accuracy deterioration degree of the reflective qualified equipment station.

[0007] Furthermore, the reference level accuracy of the anti-occlusion site is less than or equal to a preset accuracy tolerance threshold and the degradation limit level accuracy is less than or equal to a preset accuracy exemption threshold.

[0008] Furthermore, determining the preferred index for each anti-shading site includes: The minimum operating sector angle is determined based on the horizontal rotation span of each anti-obstruction site covering its effective line-of-sight point. The maximum value of the degradation level accuracy corresponding to all iterations of the anti-occlusion site and the minimum working sector angle are normalized and negatively correlated. The two processing results are then weighted and summed to obtain the optimization index of the anti-occlusion site.

[0009] Furthermore, determining the minimum operating sector angle includes: For each anti-shading site, the direction from which the anti-shading site points to all its effective line-of-sight points is recorded as the observation line direction; Arrange the angles between all observation line directions and the preset reference direction in ascending order of numerical value to obtain the observation angle sequence; obtain the first-order difference sequence of the observation angle sequence; Calculate the difference between the last element and the first element in the observation angle sequence, and subtract the difference from the total circumference angle to obtain the cross-boundary angle difference; The maximum value among all elements in the first-order difference sequence and the cross-boundary angle difference is selected, and the difference between the total circumferential angle and the maximum value is taken as the minimum operating sector angle of the anti-shading site.

[0010] Further, the selection of qualified site locations based on the coverage scale of the effective line-of-sight points includes: The percentage of the number of effective line-of-sight points of the candidate site in the sampling points is taken as the effective coverage rate; Candidate sites with an effective coverage rate greater than or equal to a preset minimum coverage threshold are designated as qualified reflection sites.

[0011] Furthermore, determining the initial set of visible reference points based on the location distribution of the reflection-qualified site and the field reference points includes: The initial set of visual reference points is formed by the line segment between the instrument viewpoint and the qualified reflection site that does not intersect with the building components in the BIM model.

[0012] Furthermore, the preset accuracy exemption threshold is less than the preset accuracy tolerance threshold.

[0013] Furthermore, the number of rows in the design matrix of the qualified reflection site is equal to the total number of field reference points in the initial set of visible reference points.

[0014] The present invention has the following beneficial effects: In this embodiment of the invention, by comprehensively considering the spatial occlusion of the BIM model and the geometric constraints of laser observation, effective line-of-sight points with high signal-to-noise ratio echoes are screened out, and qualified reflection stations are selected, thereby effectively avoiding the "pseudo-line-of-sight" ranging failure problem caused by building component occlusion or excessive observation tilt angle; by quantifying the positioning accuracy attenuation of qualified reflection stations in the single-point missing state under any missing field reference point, relative to the full set state of all simulated field reference points, the positioning accuracy degradation degree of the quantitative station positioning configuration to a specific reference point is obtained; based on the positioning accuracy degradation degree... By selecting stable, occlusion-resistant locations, the problem of total station positioning accuracy deteriorating drastically under random occlusion conditions due to excessive reliance on a few key control points in its geometric configuration is fundamentally addressed. The horizontal rotation span of the occlusion-resistant site covering its effective line-of-sight can quantify the mechanical energy efficiency of the total station's servo motor. The deterioration in positioning accuracy characterizes the system's anti-interference capability when encountering spatial occlusion interference. By integrating the above two indicators to construct an optimal index for surveying and setting out, both high-precision positioning requirements and strong configuration redundancy are met, achieving high precision and high stability in surveying and setting out under dynamic occlusion environments in complex construction sites. Attached Figure Description

[0015] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a system structure diagram of an automatic on-site surveying and layout system based on BIM, provided in one embodiment of the present invention. Figure 2 This is a system structure diagram of a positioning accuracy degradation method provided in one embodiment of the present invention; Figure 3 This is a schematic diagram of a computer device for an automated on-site surveying and layout device based on BIM, provided as an embodiment of the present invention. Detailed Implementation

[0017] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a BIM-based automatic on-site surveying and layout system proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] The following description, in conjunction with the accompanying drawings, details a specific solution for an automatic on-site surveying and layout system based on BIM provided by this invention.

[0020] Example 1: Please see Figure 1 The diagram illustrates a system block diagram of an automatic on-site surveying and layout system based on BIM according to an embodiment of the present invention. The system includes: a data acquisition module 110, a reflection quality assessment module 120, an anti-occlusion stability assessment module 130, and a layout optimization module 140.

[0021] The data acquisition module 110 is used to acquire several points to be laid out in the area to be laid out and several candidate sites of the BIM model of the area.

[0022] The area to be laid out refers to the specific physical section where surveying and calibration work is scheduled to be performed in the current construction progress. The BIM model of the area to be laid out refers to the design document containing the precise three-dimensional geometric information and topological relationships of all building components within the area. To ensure that BIM model instructions are accurately executed on site, a project spatial coordinate system is established. This coordinate system adopts a three-dimensional right-handed rectangular coordinate system: the positive X-axis is defined as due east on the horizontal plane, representing lateral displacement within the horizontal plane; the positive Y-axis is defined as due north on the horizontal plane, representing longitudinal displacement within the horizontal plane; the Z-axis is defined as the vertically upward direction perpendicular to the XY plane, usually with the elevation line of the area to be laid out as the zero point, representing the three-dimensional elevation displacement in space. The core of establishing the project spatial coordinate system lies in analyzing the design origin of the BIM model and the measurement benchmark points on the construction site, and using a spatial projection transformation algorithm to ensure that the virtual model and the physical site share a unique three-dimensional rectangular coordinate benchmark.

[0023] By analyzing the BIM model of the area to be laid out, the two-dimensional plane coordinates of key points of building components that need to be physically located on the construction site are extracted on the XY plane of the project space coordinate system as the points to be laid out. Building components refer to building objects in the BIM model that possess physical geometric attributes and objectively exist in actual construction, such as walls, columns, and their supporting components. Candidate site locations refer to potential two-dimensional plane coordinate points within the area to be laid out that can be used for total station setup. The specific method for obtaining these points is as follows: First, the horizontal projection boundaries of building components in the BIM model are analyzed and a safety buffer distance is extended outwards to obtain the restricted area; then, the walkable area is obtained by subtracting the restricted area from the two-dimensional base map of the model; subsequently, two-dimensional plane discretization sampling is performed within the walkable area according to a preset step size, thereby generating two-dimensional coordinate points that fully cover the work area and meet the safety setup conditions, which are recorded as candidate coordinates.

[0024] In this embodiment of the invention, the safety buffer distance is set based on the unfolding radius of the total station tripod and the working space required by the on-site operators; in this embodiment, it is set to 0.5 meters. The preset step size is set according to the overall size of the area to be staked out and the required optimization accuracy; in this embodiment, it is set to 0.5 meters. It should be noted that the preset step size should not exceed twice the safety buffer distance to ensure that at least one candidate station coordinate can still be effectively generated in limited passage spaces such as narrow corridors.

[0025] The reflection quality assessment module 120 is used to screen the effective line-of-sight points of each candidate site from the points to be laid out based on the spatial occlusion situation of the BIM model and the geometric constraints of laser observation; and to select qualified reflection sites based on the coverage scale of the effective line-of-sight points.

[0026] Traditional automated station planning typically involves simple line-of-sight analysis using BIM models, neglecting the physical attenuation characteristics of total station laser ranging. This leads to a "pseudo-line-of-sight" phenomenon on construction sites, where ranging fails due to excessive observation distances or large-angle sweeping reflections. By comprehensively considering spatial obstruction and laser observation geometric constraints, effective line-of-sight points with high signal-to-noise ratio echoes are selected from the physical optical path source. Since the core indicator of total station on-site layout is operational efficiency, the coverage scale of effective line-of-sight points for candidate stations is evaluated to select qualified reflection-based layout stations with high single-station operational efficiency. This mechanism effectively eliminates inefficient points with extremely low radiation workloads and requiring frequent station relocations, thereby significantly improving the spatial coverage and temporal continuity of layout operations on the construction site.

[0027] The anti-occlusion stability assessment module 130 is used to determine the positioning accuracy degradation degree of each qualified reflection site based on the single-point missing state of the simulated field reference point in the area to be laid out, relative to the full set state of all simulated field reference points; and to select the anti-occlusion sites among the qualified reflection sites.

[0028] Current automated station accuracy assessments often only calculate the ideal positioning accuracy when control points are unobstructed. However, in busy construction sites, the field control points used as the starting point for positioning calculations are easily obstructed by personnel or machinery. If the geometry of a station relies excessively on a specific reference point, the positioning calculation will collapse instantly or experience a precipitous drop in accuracy once that point is obstructed. This step determines the degree of positioning accuracy degradation of a qualified reflection station by forcibly simulating the harsh condition of missing any field reference point in the area to be surveyed, relative to the positioning accuracy attenuation under the full set of all field reference points. This reveals the vulnerability of the station's configuration to random obstruction. Furthermore, it selects anti-obstruction stations that are more balanced in terms of spatial perspective and configuration backup capabilities. This not only fundamentally avoids the hidden danger of station deployment being limited by a single key point, giving the system strong geometric redundancy and error correction and recovery capabilities, but also ensures that precision measurement tasks can be reliably executed in construction sites with frequent dynamic interference.

[0029] The layout optimization module 140 is used to determine the optimal index of each anti-obstruction site based on the horizontal rotation span and positioning accuracy degradation degree of each anti-obstruction site covering its effective line of sight, and to perform surveying and layout.

[0030] The horizontal rotation span of the anti-occlusion site covering its effective line-of-sight can quantify the mechanical efficiency of the total station's servo motor, while the degradation of positioning accuracy characterizes the system's anti-interference capability when encountering spatial occlusion interference. By integrating these two indicators, a selection index that combines mechanical efficiency and data robustness is constructed. This collaborative optimization mechanism shortens the execution sector of the total station's layout scan at the physical level, significantly reducing the probability of moving obstacles cutting off the observation optical path in the spatiotemporal dimension. This allows surveying and layout based on the selection index to break free from dependence on a single control point and effectively suppresses objective factors that trigger occlusion failures at the execution stage, ultimately achieving reliable precision positioning in complex construction site environments.

[0031] Preferably, in some possible implementations of the embodiments of the present invention, the method for obtaining effective viewpoints includes: obtaining the normal vector of the reflective surface of each point to be laid out; generating the instrument viewpoint of each candidate site based on a preset instrument setup height; for each candidate site, selecting the effective viewpoint of the candidate site from all points to be laid out; the line segment connecting the effective viewpoint and the instrument viewpoint of the candidate site does not intersect with the building components in the BIM model, the length of the line segment is less than the preset maximum measurement distance, and the angle between the vector of the effective viewpoint pointing to the instrument viewpoint of the candidate site and the normal vector of the reflective surface is less than the preset limit observation tilt angle.

[0032] It should be noted that by querying the geometric and topological properties of the surface of the building component to which each point to be laid out belongs, the unit outward normal vector of that surface in the model space is extracted and used as the reflection surface normal vector of that point. If the point to be laid out is located at the edge of a building component or at the intersection of multiple surfaces, the average vector of the unit outward normal vectors of the multiple surfaces adjacent to that point is used as the reflection surface normal vector. Based on the XY plane coordinates of the candidate site in the project space coordinate system, the preset instrument setup height is superimposed. As a vertical height component, it generates a three-dimensional instrument viewpoint for candidate sites, representing the actual spatial position of the optical center of the total station lens.

[0033] The line connecting the effective line of sight to the instrument's viewpoint at the candidate site does not intersect with the building components in the BIM model, thus meeting the requirement of unobstructed physical line of sight; the length of this line segment is less than the preset maximum measurement distance, which can ensure the echo signal-to-noise ratio of laser ranging; the angle between the vector of the effective line of sight pointing to the instrument's viewpoint at the candidate site and the normal vector of the reflecting surface is less than the preset limit observation tilt angle, which can avoid the inability to measure distance due to the attenuation of diffuse reflection echo energy caused by large-angle grazing.

[0034] In this embodiment of the invention, the preset instrument setup height refers to the operating height of the total station tripod, which is set to 1.5 meters in this embodiment; the preset maximum measurement distance is set based on the building scale of the construction site and the nominal performance of the total station's distance measuring sensor, which is set to 150 meters in this embodiment; the preset limit observation tilt angle is set according to the diffuse reflection characteristics of the material on the surface of the building entity component where the point to be laid out is located, which is set to 70 degrees in this embodiment.

[0035] Preferably, in some possible implementations of the embodiments of the present invention, the method for obtaining qualified reflection sites includes: taking the proportion of effective viewpoints of candidate sites in the stakeout points as the effective coverage rate; and identifying candidate sites with an effective coverage rate greater than or equal to a preset minimum coverage threshold as qualified reflection sites. It should be noted that the effective coverage rate quantifies the service capability of candidate sites for the stakeout task. Candidate sites with an effective coverage rate greater than or equal to the preset minimum coverage threshold possess strong global service capabilities; conversely, it indicates that the candidate site's viewing angle is severely limited, requiring frequent relocation after setup to complete surrounding tasks.

[0036] In this embodiment of the invention, the preset minimum coverage threshold depends on the spatial complexity of the construction site and the project's requirements for the efficiency of single-station operations. In this embodiment, it is set to 0.8, but implementers can set it according to their specific circumstances.

[0037] Please see Figure 2The diagram illustrates a system structure diagram of positioning accuracy degradation according to an embodiment of the present invention. The system structure diagram includes: a visual reference analysis unit 131, a design matrix design unit 132, a reference accuracy analysis unit 133, a degradation accuracy analysis unit 134, and a positioning accuracy analysis unit 135.

[0038] The visual reference analysis unit 131 is used to acquire several field reference points in the area to be laid out; for each qualified reflection station, the initial set of visual reference points is determined based on the positional distribution of the qualified reflection station and the field reference points.

[0039] It should be noted that on-site reference points refer to measurement control points pre-established on the construction site and possessing clear three-dimensional coordinates within the project's spatial coordinate system. These points can serve as absolute position references for total station rendezvous calculations. In this embodiment of the invention, on-site reference points whose line segments between the instrument's viewpoint and the qualified reflection station do not intersect with building components in the BIM model satisfy the requirement of unobstructed physical lines of sight. These on-site reference points constitute the initial visible reference points, reflecting the known three-dimensional control references that the total station can effectively observe under ideal conditions at the qualified reflection station. This provides fundamental data for evaluating the positioning reliability of the station when facing random occlusion.

[0040] Design matrix design unit 132 is used to construct a design matrix for a qualified reflection site based on an initial set of visible reference points. The elements in each row of the design matrix are the ratios of the difference in the horizontal coordinates and the difference in the vertical coordinates between the qualified reflection site and the corresponding field reference point to the horizontal projection distance between the two points.

[0041] It should be noted that this scheme focuses on horizontal positioning accuracy, therefore the design matrix is ​​constructed based on two-dimensional planar data. The design matrix has 2 columns and the number of rows is the total number of field reference points within the initial set of visible reference points; each row of the matrix corresponds to the partial derivatives of the horizontal and vertical coordinates of a field reference point. The design matrix characterizes the spatial distribution characteristics of each field reference point relative to the reflective qualified positioning station on the horizontal plane. By quantifying the azimuth characteristics of each reference point, the theoretical positioning accuracy of the positioning station under the current point layout is determined. In a specific implementation of this invention, the design matrix... Expressed as a formula: In the formula, x is the abscissa of the qualified reflection equipment station; y is the ordinate of the qualified reflection equipment station. The x-coordinate of the first field reference point in the initial set of visible reference points for each qualified reflection site; The ordinate of the first field reference point in the initial set of visible reference points for a site that meets the requirements for reflection qualification; To ensure the reflection is qualified, the horizontal projection distance between the station and the first field reference point in its initial set of visible reference points is determined. The x-coordinate of the m-th field reference point in the initial set of visible reference points for a site with acceptable reflection. The ordinate of the m-th field reference point in the initial set of visible reference points for a site that meets the reflection qualification requirements; The horizontal projection distance between the qualified reflection site and the m-th field reference point in its initial set of visible reference points; m is the total number of field reference points in the initial set of visible reference points for the qualified reflection site.

[0042] The benchmark accuracy analysis unit 133 is used to calculate the inverse matrix of the Gram matrix of the design matrix based on the least squares method, and to take the square root of the sum of the main diagonal elements of the inverse matrix as the benchmark level accuracy of the qualified reflection design site.

[0043] It should be noted that the inverse of the Gram matrix of the design matrix corresponds to the error covariance matrix of the plane coordinates to be determined for the qualified reflection station; the reference level accuracy characterizes the uniformity of the azimuth distribution and geometric configuration quality of the visible reference point set relative to the qualified reflection station. The smaller the reference level accuracy, the more robust the spatial configuration of the visible reference point set, which can effectively suppress the amplification effect of random errors in the distance and angle measurement process on the solution results, thereby ensuring a high-precision initial positioning reference for the total station under ideal unobstructed conditions.

[0044] The degradation accuracy analysis unit 134 is used to sequentially remove field reference points from the initial set of visible reference points for iterative updates, obtain the set of visible reference points for each iteration, and construct the design matrix for that iteration; the square root of the sum of the main diagonal elements of the inverse matrix of the Gram matrix of the design matrix for each iteration is used as the degradation level accuracy for that iteration.

[0045] It should be noted that this scheme employs a leave-one-out strategy, iteratively removing one field reference point from the initial set of visible reference points to obtain the set of visible reference points for each iteration, and then reconstructing the design matrix for that iteration. The degradation level accuracy characterizes the robustness of the remaining geometric configuration of a qualified reflection site after a single-point random occlusion (i.e., loss of a field reference point); a larger value indicates a higher dependence of the qualified reflection site on the feature reference point and a weaker overall geometric configuration's resistance to interference.

[0046] It is important to note that the method for constructing the design matrix for each iteration based on the set of visible reference points is the same as the method for constructing the design matrix for qualified reflection stations based on the initial set of visible reference points. During any iteration, if the determinant of the Gram matrix of the design matrix for that iteration is less than a preset anti-singularity threshold, it indicates that the configuration of the remaining field reference points after simulating the removal of a specific reference point is poor, causing matrix singularity in the total station under this missing condition. The qualified reflection stations do not possess basic anti-occlusion redundancy, and subsequent iterations updating the set of visible reference points for the qualified reflection stations are stopped, as the qualified reflection stations cannot be anti-occlusion stations. In this embodiment, the preset anti-singularity threshold is set to... .

[0047] The positioning accuracy analysis unit 135 is used to select the maximum value among all iterations of the deterioration level accuracy and record it as the deterioration limit level accuracy of the reflective qualified equipment station; the ratio of the difference between the deterioration limit level accuracy and the reference level accuracy to the reference level accuracy is used as the positioning accuracy deterioration degree of the reflective qualified equipment station.

[0048] It should be noted that, given the uncontrollable nature of random occlusion at the construction site, a safety redundancy assessment must be conducted based on the geometric configuration under the most unfavorable occlusion condition to ensure that the total station's positioning accuracy remains within a controllable range even after the loss of any critical reference point. Therefore, the maximum value among all iterations of degradation is selected as the degradation limit level accuracy. The positioning accuracy degradation metric is the proportional increase in the planar position error of a qualified reflective station relative to the ideal state under the extreme condition of single-point loss; the smaller this value, the less sensitive the station is to the physical loss of any single reference point, and the higher its geometric distribution's anti-interference redundancy.

[0049] In this embodiment of the invention, the reference horizontal accuracy of the anti-occlusion site is less than or equal to a preset accuracy tolerance threshold, and the degradation limit horizontal accuracy is less than or equal to a preset accuracy exemption threshold. It should be noted that an anti-occlusion site refers to a site that, while meeting static positioning accuracy requirements, can maintain high-precision positioning calculations even under extreme conditions such as single-point occlusion at the construction site.

[0050] In this embodiment of the invention, the preset accuracy tolerance threshold reflects the minimum static accuracy requirement for total station positioning during construction, aiming to ensure that the total station can meet the basic accuracy baseline of engineering specifications under ideal unobstructed conditions. In this embodiment, it is set to 3. The preset accuracy exemption threshold aims to provide anti-obstruction exemption for high-precision stations, and its value should be stricter than the accuracy tolerance threshold. Therefore, the preset accuracy exemption threshold should be less than the preset accuracy tolerance threshold. If the degradation limit level accuracy of a qualified reflection station is not greater than the preset accuracy exemption threshold, it indicates that under the most unfavorable single-point obstruction condition, its deteriorated absolute positioning accuracy still far exceeds the engineering surveying requirements. In this embodiment, it is set to 2.

[0051] Preferably, in some possible implementations of the embodiments of the present invention, the method for obtaining the preferred index includes: determining the minimum working sector angle based on the horizontal rotation span of each anti-occlusion site covering its effective line of sight; normalizing and negatively correlated with the maximum value and minimum working sector angle in the degradation level accuracy corresponding to all iterations of the anti-occlusion site, and weighted summing the two processing results to obtain the preferred index of the anti-occlusion site.

[0052] In this embodiment of the invention, the method for obtaining the minimum operating sector angle is as follows: For each anti-obstruction site, the direction pointing from the anti-obstruction site to all its effective line-of-sight points is recorded as the observation line of sight direction; the angles between all observation line of sight directions and a preset reference direction are arranged in ascending order of numerical value to obtain an observation angle sequence; the first-order difference sequence of the observation angle sequence is obtained; the difference between the last element and the first element in the observation angle sequence is calculated, and the total circumferential angle is subtracted from the difference to obtain the cross-boundary angle difference; the maximum value among all elements in the first-order difference sequence and the cross-boundary angle difference is selected, and the difference between the total circumferential angle and this maximum value is taken as the minimum operating sector angle of the anti-obstruction site. Wherein, the total circumferential angle is 360 degrees.

[0053] It should be noted that the observation line of sight represents the specific spatial orientation that the total station lens needs to aim at during operation; the angle between the observation line of sight and the preset reference direction is the horizontal azimuth angle obtained by unifying the observation line of sight to the same zero-degree baseline, reflecting the horizontal sector distribution characteristics of the stakeout task point relative to the anti-obstruction setting station. The maximum value among all elements in the first-order difference sequence of the observation angle sequence and the cross-boundary angle difference refers to the maximum blank blind zone that the total station does not need to scan; the minimum working sector angle quantifies the minimum horizontal arc required for the total station to cover all effective line-of-sight points. The smaller this value, the more concentrated the target distribution and the shorter the motor idle time. If the maximum value of the degraded horizontal accuracy is smaller, it means that the positioning accuracy of the anti-obstruction setting station is more stable and the configuration is more robust, and this setting station should be selected as the ideal setting station for the total station. The minimum working sector angle reflects the horizontal rotation span of the anti-obstruction setting station to cover its effective line-of-sight points; the smaller this value, the shorter the mechanical travel of the total station to complete the task, the higher the operation efficiency, and this setting station should be selected as the ideal setting station for the total station.

[0054] In this embodiment of the invention, the preset reference direction is the positive X-axis direction of the project space coordinate system.

[0055] In one specific implementation of this invention, the preferred index is expressed by the formula: In the formula, The optimal index for each anti-shading site; Minimum operating sector angle for each anti-shading site; For each anti-occlusion site, set the maximum value of the degradation level accuracy across all iterations; is the preset weighting coefficient; Norm is the normalization function. In this embodiment, based on the maximum and minimum values ​​of the minimum working sector angles of all anti-shading sites and the minimum and minimum values ​​of the maximum values ​​of the degradation level accuracy of all iterations, the minimum-maximum normalization method is used to normalize the minimum working sector angles of each anti-shading site and the maximum values ​​of the degradation level accuracy of all iterations in turn.

[0056] In this embodiment of the invention, a preset weighting coefficient is used. The numerical setting mainly depends on the emphasis placed on the two indicators of layout operation efficiency and positioning accuracy at the construction site. When the workload of the project layout is extremely large and the time requirements for single-station operation are stringent, the focus will be on the efficiency of mechanical operation, and the setting will be adjusted accordingly. Between 0.6 and 0.8, the minimum operating sector angle dominates the overall score; however, when the operating environment is extremely complex and there is a serious risk of dynamic occlusion, the focus is on the anti-interference robustness of the positioning configuration, and the setting is... Between 0.6 and 0.8. In this preferred embodiment, , This ensures that while prioritizing efficient mechanical operation, the positioning redundancy and stability of the total station in complex environments are also taken into account.

[0057] To provide intuitive on-site operational guidance, a two-dimensional planar base map is generated based on the BIM model. The optimization index of each anti-shading site is mapped to a corresponding color gradient. The higher the optimization index, the more visually significant the rendering color of the anti-shading site (e.g., tending towards warmer tones or brighter displays). This is then overlaid and rendered on the two-dimensional planar base map to generate a distribution map of the optimized site areas. Furthermore, the anti-shading site with the highest optimization index is marked on the distribution map, and the direction of the angle bisector of the minimum working sector angle corresponding to this site is used as the suggested orientation for setting up the total station. Through the guidance of this visualized distribution map, on-site operators can intuitively and accurately select the coordinates of the highest optimization index for surveying and layout, thereby ensuring that the total station maximizes the efficiency of automated layout at a single station while maintaining extremely high anti-shading reliability.

[0058] This invention is now complete.

[0059] Example 2: Figure 3 This is a schematic diagram of a computer device for an automated on-site surveying and layout device based on BIM, provided as an embodiment of the present invention. For example, as shown... Figure 3As shown, the computer device includes: a memory 201, a processor 202, and a computer program 203 stored in the memory 201 and running on the processor 202, wherein when the processor 202 executes the computer program 203, the computer device can execute any of the aforementioned BIM-based automatic on-site surveying and layout systems.

[0060] Furthermore, this application also protects an apparatus that may include a memory and a processor, wherein the memory stores executable program code, and the processor is used to call and execute the executable program code to execute the BIM-based automatic on-site surveying and layout system provided in this application.

[0061] This embodiment can divide the device into functional modules based on the above method example. For example, each module can correspond to a separate function, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0062] It should be understood that the device provided in this embodiment is used to execute the above-described BIM-based automatic on-site surveying and layout system, and therefore can achieve the same effect as the above-described implementation method.

[0063] When using integrated units, the device may include a processing module and a storage module. When applied to a workpiece, the processing module can be used to control and manage the workpiece's operations. The storage module can be used to support the execution of relevant program code by the workpiece.

[0064] The processing module may be a processor or a controller, which can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The processor may also be a combination of functions that implement computing capabilities, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and microprocessors, etc., and the storage module may be a memory.

[0065] Example 3: This embodiment also provides a computer-readable storage medium storing computer program code. When the computer program code is run on a computer, the computer executes the above-described related method steps to implement the BIM-based automatic on-site surveying and layout system provided in the above embodiment.

[0066] In this embodiment, the device and computer-readable storage medium are used to execute the corresponding system provided above. Therefore, the beneficial effects that can be achieved can be referred to the beneficial effects of the corresponding system provided above, and will not be repeated here.

[0067] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0068] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A BIM-based automatic on-site surveying and layout system, characterized in that, The system includes: The data acquisition module is used to acquire several points to be laid out in the area to be laid out and several candidate site locations in the BIM model of the area. The reflection quality assessment module is used to screen effective line-of-sight points for each candidate site from the points to be laid out based on the spatial occlusion of the BIM model and the geometric constraints of laser observation; and to select qualified reflection sites based on the coverage scale of the effective line-of-sight points. The anti-occlusion stability assessment module is used to determine the positioning accuracy degradation of each qualified reflection site based on the single-point missing state of the simulated area to be laid out, relative to the full set state of all simulated field reference points, and to select the anti-occlusion sites among the qualified reflection sites. The layout optimization module is used to determine the optimal index of each anti-obstruction site based on the horizontal rotation span of each anti-obstruction site covering its effective line of sight and the degree of positioning accuracy degradation, and to perform surveying and layout.

2. The BIM-based automatic on-site surveying and layout system according to claim 1, characterized in that, The process of selecting effective line-of-sight points for each candidate site from the points to be staked out includes: Obtain the normal vector of the reflection surface at each point to be laid out; The instrument viewpoint for each candidate instrument site is generated based on the preset instrument installation height. For each candidate site, a valid line of sight to the candidate site is selected from all the points to be laid out; the line segment connecting the valid line of sight to the instrument viewpoint of the candidate site does not intersect with the building components in the BIM model, the length of the line segment is less than the preset maximum measurement distance, and the angle between the vector of the valid line of sight pointing to the instrument viewpoint of the candidate site and the normal vector of the reflecting surface is less than the preset limit observation tilt angle.

3. The BIM-based automatic on-site surveying and layout system according to claim 2, characterized in that, The determination of the positioning accuracy degradation degree of each qualified reflection station includes: Obtain several field reference points for the area to be laid out; for each qualified reflection station, determine the initial set of visible reference points based on the positional distribution of the qualified reflection station and the field reference points; A design matrix for qualified reflection equipment sites is constructed based on an initial set of visible reference points. The elements in each row of the design matrix are the ratios of the difference in the horizontal coordinates and the difference in the vertical coordinates between the qualified reflection equipment site and the corresponding field reference point to the horizontal projection distance between the two points. The inverse matrix of the Gram matrix of the design matrix is ​​calculated using the least squares method, and the square root of the sum of the main diagonal elements of the inverse matrix is ​​used as the reference level accuracy of the qualified reflection design site. The field reference points are removed sequentially from the initial set of visible reference points for iterative updates to obtain the set of visible reference points for each iteration, and the design matrix for that iteration is constructed. The square root of the sum of the main diagonal elements of the inverse of the Gram matrix of the design matrix for each iteration is taken as the degradation level precision for that iteration. The maximum value among all iterations of the deterioration level accuracy is selected and recorded as the deterioration limit level accuracy of the reflective qualified equipment station; the ratio of the difference between the deterioration limit level accuracy and the reference level accuracy to the reference level accuracy is taken as the positioning accuracy deterioration degree of the reflective qualified equipment station.

4. The BIM-based automatic on-site surveying and layout system according to claim 3, characterized in that, The baseline level accuracy of the anti-shading site is less than or equal to a preset accuracy tolerance threshold, and the degradation limit level accuracy is less than or equal to a preset accuracy exemption threshold.

5. The BIM-based automatic on-site surveying and layout system according to claim 3, characterized in that, The determination of the preferred index for each anti-shading site includes: The minimum operating sector angle is determined based on the horizontal rotation span of each anti-obstruction site covering its effective line-of-sight point. The maximum value of the degradation level accuracy corresponding to all iterations of the anti-occlusion site and the minimum working sector angle are normalized and negatively correlated. The two processing results are then weighted and summed to obtain the optimization index of the anti-occlusion site.

6. The BIM-based automatic on-site surveying and layout system according to claim 5, characterized in that, Determining the minimum operating sector angle includes: For each anti-shading site, the direction from which the anti-shading site points to all its effective line-of-sight points is recorded as the observation line direction; Arrange the angles between all observation line directions and the preset reference direction in ascending order of numerical value to obtain the observation angle sequence; obtain the first-order difference sequence of the observation angle sequence; Calculate the difference between the last element and the first element in the observation angle sequence, and subtract the difference from the total circumference angle to obtain the cross-boundary angle difference; The maximum value among all elements in the first-order difference sequence and the cross-boundary angle difference is selected, and the difference between the total circumferential angle and the maximum value is taken as the minimum operating sector angle of the anti-shading site.

7. The BIM-based automatic on-site surveying and layout system according to claim 1, characterized in that, The selection of qualified site locations based on the coverage scale of the effective line-of-sight points includes: The percentage of the number of effective line-of-sight points of the candidate site in the sampling points is taken as the effective coverage rate; Candidate sites with an effective coverage rate greater than or equal to a preset minimum coverage threshold are designated as qualified reflection sites.

8. The BIM-based automatic on-site surveying and layout system according to claim 3, characterized in that, The determination of the initial set of visible reference points based on the location distribution of the reflection-qualified site and the field reference points includes: The initial set of visual reference points is formed by the line segment between the instrument viewpoint and the qualified reflection site that does not intersect with the building components in the BIM model.

9. The BIM-based automatic on-site surveying and layout system according to claim 4, characterized in that, The preset accuracy exemption threshold is less than the preset accuracy tolerance threshold.

10. The BIM-based automatic on-site surveying and layout system according to claim 1, characterized in that, The number of rows in the design matrix of the qualified reflection site is equal to the total number of field reference points in the initial set of visible reference points.

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