A method for measuring building tilt based on total station DR mode

Abstract

This invention discloses a method for measuring building tilt based on total station DR mode, comprising the following steps: 1. Establishing a distance measurement error compensation model using distance measurement experiments of characteristic points on the building; 2. Establishing a high-precision three-dimensional control network based on the site conditions of the building; 3. Selecting characteristic points for building tilt measurement and estimating the height of these characteristic points above the ground; 4. Estimating the station location based on the height of these characteristic points above the ground, and precisely adjusting the station location using observations from the total station DR mode; 5. Analyzing and compensating for the distance observations based on the DR mode distance measurement error compensation model; 6. Calculating the coordinates of the characteristic points for building tilt measurement and obtaining the building tilt amount. This invention, based on total station DR mode distance measurement error correction and the establishment of a high-precision three-dimensional control network, offers high accuracy and reliability, allowing tilt measurement work to be carried out without contact with the building, making it suitable for use in sudden, extremely dangerous site environments.

Description

Technical Field

[0001] This invention belongs to the field of building tilt measurement technology, specifically relating to a building tilt measurement method based on total station DR mode. Background Technology

[0002] During construction and before final acceptance, tilt monitoring of the building's superstructure, walls, columns, etc., is recommended. During the building's operational phase, when tilting occurs, timely tilt monitoring should be conducted. The results provide relevant reference data for design and construction departments, enabling timely intervention to achieve safe construction and eliminate potential hazards. Building tilt monitoring measures the verticality of the building itself to understand the stability of the foundation piles at different stages of construction. The tilt measurement of the main building should determine the tilt degree, direction, and rate of tilt of the observation point at the top relative to the bottom or upper floor relative to the lower floor. Commonly used methods for building tilt monitoring include theodolite projection, forward intersection, laser collimation, plumb line method, suspended plumb bob method, and differential settlement method.

[0003] The theodolite projection method involves placing a horizontal reading ruler or other measuring equipment at the observation point at the bottom of the building. The horizontal displacement components between each pair of upper and lower observation points are measured using the direct and inverted mirror method. The horizontal displacement value (tilt) and direction (tilt direction) are then calculated using the vector addition method. This method requires auxiliary measuring tools such as reading rulers, and its accuracy is significantly affected by these tools, making it difficult to implement. The forward convergence method determines the coordinates of unknown observation points by observing them from a number of known points. This method requires good visibility and is easily affected by the environment, leading to either inability to conduct observations or poor-quality results. The laser collimation method involves placing a receiving target at an appropriate location on the top of the building, and then placing a laser plumb line or laser theodolite on the ground or floor below it. The horizontal displacement and direction at the top are directly read or measured from the receiving target. This method requires good on-site observation conditions and requires station setup during the building's operation phase. The following methods present certain challenges: The plumb line method involves installing a plumb line with protective devices and auxiliary facilities to provide tension within the building. Displacement is measured using coordinate instruments, optical plumb lines, or inductive plumb lines mounted on observation piers. This method is labor-intensive, difficult to organize and implement, and inefficient. The plumb bob method involves directly suspending or extending a point to suspend a plumb bob of appropriate weight at the observation point on the top of the building or at the desired height. A reading device (such as a millimeter grid reading board) is fixed at the bottom of the plumb line to directly read or measure the horizontal displacement and direction of the upper observation point relative to the lower observation point. This method is greatly affected by the observation environment and cannot be used under conditions of high wind speed or tall buildings. The differential settlement method indirectly determines the building's tilt by measuring the relative settlement of the building using leveling instruments or other measuring equipment. This method requires a certain observation period and reflects the building's tilt within that period, making it unsuitable for determining the building's current total tilt. All of these methods are easily constrained by the site environment during organization and implementation, are relatively cumbersome, and have poor adaptability to special observation conditions. Traditional methods for observing the tilt of buildings during operation face challenges such as the lack of equipment deployment conditions or high operational difficulty.

[0004] At this point, the total station's non-contact measurement, or DR (Direct Reflection) mode, can directly measure targets that meet the distance measurement conditions without the aid of cooperative targets, prisms, reflectors, etc. This is particularly suitable for special measurement scenarios where cooperative targets cannot be set up, such as building corners where prisms or reflectors cannot be placed. The total station's DR mode calculates the equivalent distance based on the entire reflection area illuminated by the collected laser spot. This is affected not only by factors such as the color and roughness of the target surface and the area of ​​the measurement point, but also, in practical applications, often by weak reflection signals from the target or the simultaneous reception of reflection signals from multiple targets, leading to unreliable measurement results. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for measuring building tilt based on the total station's DR mode. By analyzing and correcting the distance measurement error of the total station's DR mode, the accuracy and stability of its three-dimensional point coordinate measurement can be improved to a certain extent. This method enables rapid and accurate tilt measurement of buildings, timely and effective feedback of tilt measurement information, and provides basic data support and information guidance for building safety status analysis and decision-making, making it easy to promote and use.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for measuring building tilt based on total station DR mode, characterized in that the method includes the following steps:

[0007] Step 1: Calculate the sequence of changes in spot size with laser propagation distance based on the laser beam divergence of the total station, and establish a distance measurement error compensation model using distance measurement experiments of building feature points;

[0008] Step 2: Establish a high-precision three-dimensional control network based on the site conditions of the building to provide a global coordinate reference benchmark for the building tilt measurement;

[0009] Step 3: Select building tilt measurement feature points from the building feature points and estimate the height of the building tilt measurement feature points above the ground;

[0010] Step 4: Estimate the station location based on the height of the building tilt measurement feature points above the ground, and accurately adjust the station location using the observation values ​​in DR mode of a total station;

[0011] Step 5: Use the total station's DR mode to collect data on the building's tilt measurement feature points, and analyze and compensate for the distance observations based on the DR mode's distance measurement error compensation model;

[0012] Step 6: Calculate the coordinates of the building tilt measurement feature points using the compensated distance adjustment values, and calculate the building tilt amount based on the coordinates of the building tilt measurement feature points.

[0013] The above-mentioned method for measuring building tilt based on total station DR mode is characterized in that: in step one, the building feature points include building internal corner feature points, building external corner feature points, and building special external corner feature points. The building internal corner feature points include right trihedral angle feature points and right dihedral angle feature points. The building external corner feature points are right dihedral angle supplementary angle feature points. The building special external corner is a special external corner composed of three mutually perpendicular faces.

[0014] The above-mentioned method for measuring building tilt based on total station DR mode is characterized in that: in step two, firstly, multiple prisms are set up around the building site as global control points for orientation of each station; secondly, the number of stations is planned according to the number of building feature points, and adjustment calculations are performed with any station as the benchmark to establish a high-precision three-dimensional control network.

[0015] The above-mentioned method for measuring building tilt based on total station DR mode is characterized in that: in step three, firstly, the building tilt measurement feature points are selected in groups of two, and the two building tilt measurement feature points in each group are recorded as low feature point and high feature point respectively according to their height above the ground from low to high; secondly, the height above the ground of each group of building tilt measurement feature points is estimated to provide reference data for total station setup.

[0016] The above-mentioned method for measuring building tilt based on total station DR mode is characterized in that: in step four, the direction of the total station is determined by using the bisector of the horizontal projection angle of the location of each group of building tilt measurement feature points as a reference; the design height difference between the high and low feature points is used as the reference distance from the center of the total station to the straight line where each group of building tilt measurement feature points is located to determine the station location; the height of the low feature point above the ground in each group of building tilt measurement feature points is used as the reference height for station location; the height of the high and low feature points above the ground is initially observed, and the station location is precisely adjusted based on this reference.

[0017] The above-mentioned method for measuring building tilt based on total station DR mode is characterized in that: in step five, the angle and distance observation values ​​of the building tilt measurement feature points are obtained using the total station DR mode; and the distance observation values ​​are analyzed and compensated based on the distance observation values ​​of the total station DR mode.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. This invention is almost unrestricted by site conditions, has strong environmental adaptability, and is especially suitable for tilt measurement of buildings in operation, making it easy to promote and use.

[0020] 2. This invention is based on the distance measurement error correction of total station DR mode and the establishment of a high-precision three-dimensional control network. Its accuracy and reliability are guaranteed, and it is reliable, stable and effective.

[0021] 3. The method of the present invention has simple steps and is a non-contact measurement method. It can carry out tilt measurement work without contacting the building. It is easy to operate and suitable for use in sudden and extremely dangerous on-site environments. It ensures the safety of the observers to a certain extent and is easy to promote and use.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a flowchart of the method of the present invention.

[0024] Figure 2 This is a schematic diagram simulating the concave angle (right trihedral angle) of a building according to the present invention.

[0025] Figure 3 This is a schematic diagram simulating the concave angle (right dihedral angle) of a building according to the present invention.

[0026] Figure 4 This is a schematic diagram simulating the external corner (supplementary dihedral angle) of a building according to the present invention.

[0027] Figure 5 This is a schematic diagram simulating a special external angle of a building according to the present invention. Detailed Implementation

[0028] like Figures 1 to 5 As shown, the present invention provides a method for measuring building tilt based on total station DR mode, comprising the following steps:

[0029] Step 1: Calculate the sequence of changes in spot size with laser propagation distance based on the laser beam divergence of the total station, and establish a distance measurement error compensation model using distance measurement experiments of building feature points;

[0030] Step 2: Establish a high-precision three-dimensional control network based on the site conditions of the building to provide a global coordinate reference benchmark for the building tilt measurement;

[0031] Step 3: Select building tilt measurement feature points from the building feature points and estimate the height of the building tilt measurement feature points above the ground;

[0032] Step 4: Estimate the station location based on the height of the building tilt measurement feature points above the ground, and accurately adjust the station location using the observation values ​​in DR mode of a total station;

[0033] Step 5: Use the total station's DR mode to collect data on the building's tilt measurement feature points, and analyze and compensate for the distance observations based on the DR mode's distance measurement error compensation model;

[0034] Step 6: Calculate the coordinates of the building tilt measurement feature points using the compensated distance adjustment values, and calculate the building tilt amount based on the coordinates of the building tilt measurement feature points.

[0035] In this embodiment, in step one, the building feature points include building internal corner feature points, building external corner feature points, and building special external corner feature points. The building internal corner feature points include right trihedral feature points and right dihedral feature points. The building external corner feature points are right dihedral supplementary corner feature points. The building special external corner is a special external corner composed of three mutually perpendicular faces.

[0036] In this embodiment, in step two, firstly, multiple prisms are set up around the building site as global control points for orientation of each station; secondly, the number of stations is planned according to the number of building feature points, and adjustment calculations are performed using any station as a reference to establish a high-precision three-dimensional control network.

[0037] In this embodiment, in step three, firstly, the building tilt measurement feature points are selected in groups of two, and the two building tilt measurement feature points in each group are recorded as low feature point and high feature point respectively according to their height above the ground from low to high; secondly, the height above the ground of each group of building tilt measurement feature points is estimated to provide reference data for the total station setting.

[0038] In this embodiment, in step four, the direction of the total station is determined by using the bisector of the horizontal projection angle of the location of each group of building tilt measurement feature points as a reference; the design elevation difference between the high and low feature points is used as the reference distance from the center of the total station to the straight line where each group of building tilt measurement feature points is located to determine the station location; the height of the low feature point above the ground in each group of building tilt measurement feature points is used as the reference height for station location; the height of the high and low feature points above the ground is initially observed, and the station location is precisely adjusted based on this reference.

[0039] In this embodiment, in step five, the angle and distance observation values ​​of the building tilt measurement feature points are obtained using the total station's DR mode; the distance observation values ​​are then analyzed and compensated based on the distance observation values ​​from the total station's DR mode.

[0040] It should be noted that the prism measurement mode of a total station and the DR mode have comparable angular measurement accuracy, but the former has an advantage in distance measurement accuracy. Therefore, the former offers higher point measurement accuracy than the latter. In practical applications, situations often arise where it is impossible to set up a prism or other cooperative target, necessitating the use of the total station's DR mode for measurement work. For operating buildings with complex exterior facade structures, where cooperative targets are unavailable, the DR mode of the total station must be used for tilt measurements.

[0041] Taking the Trimble S8 total station as an example, this instrument includes both visible and invisible laser sources. In DR mode, the laser diode for distance measurement and laser aiming functions operates at 660nm (visible light), with a beam divergence of 0.4×0.4mrad and an output power of <1mW (when the emitted beam is coaxial with the telescope). In prism mode, the laser diode for distance measurement functions operates at 660nm (visible light), with a beam divergence of 0.4×0.4mrad and an output power of <0.017mW (when the emitted beam is coaxial with the telescope). In auto-lock mode, the laser diode operates at 785nm (non-visible infrared light), with a beam divergence of 38.5mrad and an output power of <0.35mW (when the emitted beam is coaxial with the telescope).

[0042] The change sequence of spot size with distance is calculated based on the laser beam divergence in DR mode, and the formula for calculating the divergence angle of monochromatic laser is used. Where D is the diameter of the beam and L is the distance.

[0043] Given that the beam divergence of the Trimble S8 total station is 0.4 × 0.4 mrad, based on the above formula, the variation of the laser spot diameter with distance as the beam propagates in DR mode can be calculated as shown in Table 1.

[0044] Table 1

[0045]

[0046] Theoretically, the distance acquired by a total station in DR mode is the equivalent signal of all reflected signals after the laser beam is naturally reflected from the target. The equivalent distance generated by this equivalent signal is: In the formula, e is the reflected signal number, E is the total number of reflected signals, and q e P is the distance from the e-th reflected signal to the center of the instrument. e It is the weight of the e-th reflected signal.

[0047] Distance measurement experiments were conducted using simulated building internal angles (right trihedral angles), and the results are shown in Table 2.

[0048] Table 2

[0049]

[0050] Table 2 shows that in the scene of the building's inner corner (right trihedral angle), the difference between the prism mode and the DR mode is related to the spot diameter. The following model is established: Where K1 is the difference coefficient, s1 is the distance difference between prism mode and DR mode, d is the spot diameter, and L is the distance measurement result in DR mode.

[0051] The distance measurement error compensation value V1 in the scenario of the building's internal angle (right trihedral angle) can be calculated using the above formula.

[0052] Distance measurement experiments were conducted in DR mode using simulated building planes, internal angles (right dihedral angles), and external angles (supplementary angles of right dihedral angles). The distance measurement results are shown in Table 3.

[0053] Table 3

[0054]

[0055] Furthermore, as shown in the table above, the difference in DR mode is related to the spot diameter in scenarios involving building plan, concave corner (right dihedral angle), and convex corner (supplementary angle of right dihedral angle). The following model is established: Where K2 is the level difference coefficient, K3 is the level difference coefficient, s2 is the level difference in DR mode, s3 is the level difference in DR mode, d is the spot diameter, and L is the ranging result in DR mode.

[0056] The above formula can be used to calculate the ranging error compensation value V2 in the case of a concave angle (right dihedral angle) and the ranging error compensation value V3 in the case of a convex angle (supplementary angle of a right dihedral angle).

[0057] An error compensation model can be derived for special external angles of buildings (special external angles formed by three mutually perpendicular surfaces, whose reflection effect is approximately equivalent to the combination of an internal angle of a regular trihedral face and a right dihedral angle supplementary angle):

[0058] The distance measurement error compensation value V4 for special external angles of buildings can be calculated using the above formula. At this point, the distance measurement error compensation model for common feature points of buildings has been established.

[0059] n control points are set up around the building. m measuring stations are set up around the building using an S8 total station. The angle and distance of each control point are observed at each measuring station using the S8 total station, thus forming a spatial three-dimensional edge-angle network.

[0060] Let the angle and distance observed from the i-th station to the j-th control point be (Hz). ij V ij ,S ijTherefore, the coordinates of the j-th control point at the i-th station are calculated as (X... ij ,Y ij Z ij Let the rotation parameter from the coordinate system of the i-th station of the S8 total station to the global coordinate system be... Translation parameters are The coordinates of the j-th control point in the global coordinate system are (X... j ,Y j Z j According to the principle of coordinate system transformation: Where, n i1 ,n i2 ,n i3 ,o i1 ,o i2 ,o i3 ,a i1 ,a i2 ,a i3 Rotation parameters for the i-th station The function, if rotated in the order of the X-axis, Y-axis, and Z-axis, then has:

[0061] The S8 total station is strictly leveled at each station. At this point, the rotation parameter from the coordinate system of the i-th station to the global coordinate system becomes... The above formula can be transformed into the following under the leveled state:

[0062] Furthermore, the angle and distance observation values ​​of the i-th station to the j-th control point are (Hz). ij V ij ,S ij The coordinate system O of the j-th control point at the i-th station. i -X i Y i Z i The coordinates in (X) are ij ,Y ij Z ij From the coordinates of the control points, the horizontal angle observation and the zenith distance observation can be calculated as follows:

[0063] In the above formula, the coordinates of the control points are in the station coordinate system. Using the coordinate transformation formula above, they can be converted to the survey coordinate system, resulting in:

[0064] In the measurement coordinate system, the functional relationship between the point coordinates and the distance observation is as follows:

[0065] Linearizing the formulas for the above observations and expanding them using Taylor series while retaining the first-order terms, we can construct the error equation as: V = A·δX⁻¹, where, δX is the residual vector of all observations, A is the coefficient matrix, δX is the residual vector of each parameter, and l is the vector of constant terms.

[0066] Let the observation weight matrix be P. By the least squares principle, the residual value of the unknown parameter is δX = (A T PA) -1 ·A T Pl.

[0067] Let the initial value of the parameter be X0. The adjusted value of the parameter can be obtained by adding the initial value X0 to the residual value δX.

[0068] In actual building tilt measurement, L1 station is used as the starting station for the entire network adjustment. The data of the other stations are converted to the L1 station coordinate system. That is, after the adjustment, the parameters of each station and the coordinates of the control points are all data in the L1 station coordinate system.

[0069] Based on the building design drawings and the site conditions, select points with representative shape characteristics on the outer surface of the building as the measurement points for tilt measurement features, such as the above-mentioned building's internal corners (right trihedral angles), internal corners (right dihedral angles), external corners (supplementary angles of right dihedral angles), special external corners, etc., and estimate the height of the feature points above the ground based on the building design drawings.

[0070] The station location is roughly calculated based on the estimated height of the feature points above the ground. The direction of the station is determined by using the bisector of the horizontal projection angle of the positive or negative angle where each set of feature points is located as a reference. The design elevation difference between the high and low feature points is used as the reference distance from the instrument center to the straight line where each set of feature points is located to determine the station location. The height of the low feature point above the ground is used as the reference height for the station.

[0071] The initial observations of the height above the ground of high and low feature points were used as a reference to precisely adjust the position of the measuring station.

[0072] Based on the established high-precision three-dimensional control network, feature point data are acquired using a total station in DR mode. The distance observations are then analyzed and compensated according to the aforementioned DR mode distance measurement error compensation model. The coordinates of the building's feature points are calculated using the compensated distance adjustment values, and the building's tilt is calculated based on these coordinates.

[0073] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A building tilt measurement method based on a total station DR mode, characterized in that, The method includes the following steps: Step 1: Calculate the sequence of changes in spot size with laser propagation distance based on the laser beam divergence of the total station, and establish a DR mode ranging error compensation model using ranging experiments of building feature points; Step 2: Establish a high-precision three-dimensional control network based on the site conditions of the building to provide a global coordinate reference benchmark for the building tilt measurement; Step 3: Select building tilt measurement feature points from the building feature points and estimate the height of the building tilt measurement feature points above the ground; Step 4: Estimate the station location based on the height of the building tilt measurement feature points above the ground, and accurately adjust the station location using the distance observation values ​​in total station DR mode; Step 5: Use the total station's DR mode to collect data on the building's tilt measurement feature points, and analyze and compensate for the distance observations based on the DR mode's distance measurement error compensation model; Step 6: Calculate the coordinates of the building tilt measurement feature points using the compensated distance adjustment values, and calculate the building tilt based on the coordinates of the building tilt measurement feature points; In step three, firstly, the building tilt measurement feature points are selected in groups of two. The two building tilt measurement feature points in each group are recorded as the low feature point and the high feature point respectively, according to their height above the ground from low to high. Secondly, the height above the ground of each group of building tilt measurement feature points is estimated to provide reference data for the total station setup. In step four, the direction of the total station is determined by using the bisector of the horizontal projection angle of the location of each group of building tilt measurement feature points as a reference; the design elevation difference between the high and low feature points is used as the reference distance from the center of the total station to the straight line where each group of building tilt measurement feature points is located to determine the station location; the height of the low feature point above the ground in each group of building tilt measurement feature points is used as the reference height for station location; the height of the high and low feature points above the ground is initially observed, and the station location is precisely adjusted based on this reference. In step five, the angle and distance observation values ​​of the building tilt measurement feature points are obtained using the total station's DR mode; the distance observation values ​​are then analyzed and compensated based on the total station's DR mode distance observation values.

2. The building inclination measurement method based on the total station DR mode according to claim 1, characterized in that: In step one, the building feature points include the building's internal corner feature points, the building's external corner feature points, and the building's special external corner feature points. The building's internal corner feature points include the right trihedral corner feature points and the right dihedral corner feature points. The building's external corner feature points are the right dihedral supplementary corner feature points. The building's special external corner is a special external corner formed by three mutually perpendicular faces.

3. The building inclination measurement method based on the total station DR mode according to claim 1, characterized in that: In step two, firstly, multiple prisms are set up around the building site as global control points for orientation at each station; Secondly, the number of monitoring stations is planned based on the number of building feature points, and adjustment calculations are performed using any one monitoring station as a benchmark to establish a high-precision three-dimensional control network.

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