Method for improving three-dimensional positioning precision of laser ranging instrument based on orientation point model

Abstract

The invention relates to the field of precision measurement, in particular to a method for improving the three-dimensional positioning precision of a laser ranging instrument based on an orientation point model, which comprises the following steps: designing and processing the orientation point model, installing reflection assemblies on the processed orientation point model, measuring the three-dimensional coordinates of each reflection assembly by using metering-level space pose measurement equipment, and calculating the three-dimensional positioning precision of the laser ranging instrument. Measuring the distance between each laser distance measuring instrument and each reflection assembly by using each laser distance measuring instrument; the measurement result of the metering-level space pose measurement equipment and the measurement result of each laser distance measurement instrument are used for calculation through a space resection method, and the three-dimensional coordinate of each laser distance measurement instrument is obtained; and measuring the distance between each laser distance measuring instrument and the target point by using each laser distance measuring instrument, combining with the three-dimensional coordinate of each laser distance measuring instrument, and performing calculation through a space forward intersection method to obtain the three-dimensional coordinate of the target point. According to the invention, the measurement precision of the laser ranging instrument can be improved, and micron-sized high-precision pose measurement is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of precision measurement, and in particular relates to a method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model. Background Art

[0002] High-precision positioning is crucial in many precision measurement fields. With the advancement of science and technology, the requirements for precise positioning and adjustment accuracy of systems in aerospace, machinery manufacturing and installation, optical system adjustment, precision engineering and industrial measurement are constantly increasing. Laser trackers, as a common high-precision three-dimensional positioning tool, are widely used in these fields, especially in the process of auxiliary adjustment and positioning. The single-unit accuracy of existing laser trackers, such as the full-range coordinate accuracy of Leica AT960 Tracker, is 15μm+6μm / m. As the measurement distance increases, the error gradually increases, which cannot meet the growing demand for positioning accuracy.

[0003] The measurement system of the laser tracker is essentially a spherical coordinate measurement system. It calculates the three-dimensional spatial coordinates of the target point by measuring the distance to the target point and the deflection angles in the horizontal and vertical directions. Therefore, the positioning accuracy of the target point is mainly affected by the ranging accuracy and the angular measurement accuracy. The laser tracker measures distance based on the principle of laser interference and can accurately measure spatial distances. For example, the existing laser tracker Leica AT960 IFM has a ranging accuracy of up to 0.5μm / m, but the angular measurement error of the laser tracker is still the main limiting factor of angular measurement accuracy. If you can focus on high-precision ranging, you can significantly improve the positioning accuracy of the target point.

[0004] At present, the edge measurement network adjustment method is usually used to improve the positioning accuracy of the target point. The edge measurement network adjustment method uses four or more laser trackers to jointly measure, takes the coordinates measured by a single laser tracker as the initial value, and uses the high-precision distance data of the pure distance measurement mode for adjustment calculation, thereby improving the positioning accuracy of the target point. The edge measurement network adjustment method eliminates the angle measurement error of the laser tracker and makes full use of the high-precision advantage of laser interferometry to significantly improve the positioning accuracy of the target point. However, due to the low accuracy and insufficient stability of the coordinates measured by a single laser tracker, the measurement results are restricted by the accuracy of the initial value.

[0005] The Chinese invention patent with publication number CN117724041A and publication date March 19, 2024, proposes a laser multi-lateration measurement method and system based on spatial multi-distance constraints, aiming to improve measurement accuracy. However, this measurement method can only obtain relative distances and only provides distance constraints in the horizontal plane, resulting in a complicated layout process and a final accuracy of only about 10μm, which is difficult to meet higher positioning accuracy requirements. Summary of the invention

[0006] In view of this, the present invention aims to provide a method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model, so as to solve the technical problem of low positioning accuracy of existing laser ranging instruments.

[0007] To achieve the above object, the technical solution created by the present invention is implemented as follows: A method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model comprises the following steps: S1: Design a geometrically stable directional point model based on the uniform distribution principle and polygon stability principle; S2: Process the designed orientation point model, and reasonably arrange the orientation points on the processed orientation point model to ensure that each laser ranging instrument can observe all orientation points; S3: Install a reflective component at each orientation point, measure the three-dimensional coordinates of each reflective component using a metrology-grade spatial posture measurement device, and arrange at least three measuring stations, place a laser rangefinder at each measuring station, and use each laser rangefinder to measure the distance between each and each reflective component; S4: using the three-dimensional coordinates of each reflective component and the distance between each laser ranging instrument and each reflective component, a spatial resection method based on the least squares method is used to calculate and obtain the three-dimensional coordinates of each measuring station; S5: Install the reflective component on the target point, use each laser ranging instrument to measure the distance between each and the target point, and combine it with the three-dimensional coordinates of each measuring station, and calculate it through the spatial forward intersection method based on the least squares method to obtain the three-dimensional coordinates of the target point.

[0008] Further, in step S4, the three-dimensional coordinates of the first reflection component are set to , the three-dimensional coordinates of the remaining reflection components are , the three-dimensional coordinates of a station point are , then the distance between the first reflector and the laser distance measuring instrument corresponding to the station point is for:

[0009] The distance between the remaining reflective components and the laser distance measuring instrument corresponding to the measuring station for:

[0010] Decomposing equation (1) and equation (2) yields:

[0011]

[0012] Combining equation (3) and equation (4) we get:

[0013] After rearranging formula (5), we can get:

[0014] Assume that the number of reflection components is six, and the three-dimensional coordinates of the first reflection component are , the three-dimensional coordinates of the remaining reflection components are ~ , formula (6) is transformed into an overdetermined system of equations:

[0015] The three-dimensional coordinates of the measuring station are obtained by the least squares method Solve and obtain the three-dimensional coordinates of the measuring station.

[0016] Further, in step S5, the three-dimensional coordinates of the first measuring station are set to , the three-dimensional coordinates of the reflection components of the other station points are , the three-dimensional coordinates of the target point are , then the distance between the first measuring station and the target point for:

[0017] The distance between the remaining measuring stations and the laser distance measuring instrument corresponding to the target point for:

[0018] Decomposing equation (8) and equation (9) we can get:

[0019]

[0020] Combining equation (10) and equation (11), we get:

[0021] By rearranging formula (12), we can obtain: ; Assume that there are four measuring stations and the three-dimensional coordinates of the first measuring station are The three-dimensional coordinates of the other measuring stations are ~ , formula (13) is transformed into a system of equations:

[0022] The three-dimensional coordinates of the target point Solve and obtain the three-dimensional coordinates of the target point.

[0023] Further, the orientation point model is a cube frame, including eleven cross bars and four vertical bars. The first cross bar, the second cross bar, the third cross bar, and the fourth cross bar constitute the bottom surface of the cube frame, the fifth cross bar, the sixth cross bar, the seventh cross bar, and the eighth cross bar constitute the top surface of the cube frame, the first cross bar, the fifth cross bar, the first vertical bar and the second vertical bar, the second cross bar, the sixth cross bar, the second vertical bar and the third vertical bar, the third cross bar, the seventh cross bar, the third vertical bar and the fourth vertical bar, the fourth cross bar, the eighth cross bar, the first vertical bar and the fourth vertical bar respectively constitute the four side surfaces of the cube frame, the ninth cross bar is connected between the midpoint of the fifth cross bar and the midpoint of the seventh cross bar, the tenth cross bar is connected between the midpoint of the third vertical bar and the midpoint of the fourth vertical bar, and the eleventh cross bar is connected between the midpoint of the fourth vertical bar and the midpoint of the first vertical bar.

[0024] Furthermore, the material of the directional point model is silicon carbide composite material, titanium alloy material, Invar alloy material or carbon fiber 3D printing material.

[0025] Furthermore, the number of orientation points is six, which are respectively arranged at the two ends of the first crossbar, the midpoints of the ninth crossbar, the tenth crossbar, the eleventh crossbar, and the intersection of the seventh crossbar and the eighth crossbar.

[0026] Furthermore, the metrology-grade spatial posture measurement equipment is a three-coordinate measuring machine.

[0027] Furthermore, the laser ranging instrument is a laser tracker, a laser interferometer or a laser tracking interferometer. When the laser ranging instrument is a laser tracker, the reflection component adopts a target ball specially used for the laser tracker; when the laser ranging instrument is a laser tracking interferometer, the reflection component adopts a cat's eye retro-reflector specially used for the laser tracking interferometer; when the laser ranging instrument is a laser interferometer, the reflection component adopts a plane reflector, a corner cube prism, a right-angle prism or a cat's eye retro-reflector specially used for the laser interferometer.

[0028] Compared with the prior art, the invention can achieve the following beneficial effects: The present invention utilizes the spatial multi-distance constrained directional point model and the high-precision distance measurement technology of the laser distance measuring instrument to obtain high-precision station coordinates, laying a high-precision station foundation for subsequent network adjustment, thereby improving the measurement accuracy of the laser distance measuring instrument, and realizing micron-level high-precision posture measurement, meeting the requirements for system precise positioning and adjustment accuracy in the fields of aerospace, mechanical manufacturing and installation, optical system adjustment, precision engineering and industrial measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 It is a flow chart of a method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model according to an embodiment of the invention.

[0030] Figure 2 It is a structural schematic diagram of the directional point model described in the embodiment of the invention.

[0031] Figure 3 It is a schematic diagram of a spatial resection formed by a reflective assembly and a laser rangefinder according to an embodiment of the present invention.

[0032] Figure 4 It is a schematic diagram of intersection measurement of a laser ranging instrument according to an embodiment of the invention.

[0033] Figure 5 It is a schematic diagram of a spatial forward intersection formed by a target point and a laser rangefinder according to an embodiment of the present invention.

[0034] Explanation of the accompanying drawings: orientation point model 1, first reflection component 11, second reflection component 12, third reflection component 13, fourth reflection component 14, fifth reflection component 15, sixth reflection component 16, first cross bar 101, second cross bar 102, third cross bar 103, fourth cross bar 104, fifth cross bar 105, sixth cross bar 106, seventh cross bar 107, eighth cross bar 108, ninth cross bar 109, tenth cross bar 110, eleventh cross bar 111, first vertical bar 112, second vertical bar 113, third vertical bar 114, fourth vertical bar 115, laser ranging instrument 21, target 3, target point 31. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0036] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0038] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0039] The following will refer to Figure 1-Figure 5 The invention is described in detail with reference to the embodiments.

[0040] like Figure 1 As shown, the method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model provided by an embodiment of the present invention includes the following steps: S1: Design a geometrically stable directional point model based on the uniform distribution principle and polygon stability principle.

[0041] S2: Process the designed orientation point model, and reasonably arrange the orientation points on the processed orientation point model to ensure that each laser ranging instrument can observe all the orientation points.

[0042] Based on the principle of uniform distribution and polygon stability, ensure that the orientation points are evenly distributed on the XY, XZ, and YZ planes, and cover the angle areas between the planes as much as possible, so that these angle surfaces have geometric constraints. In the design, the geometric constraints of the orientation points should not be too concentrated on a certain point or a certain area, but should be evenly distributed on all orientation points to ensure the overall geometric stability and measurement accuracy of the orientation point model. Under the premise of ensuring that each laser ranging instrument can see all orientation points, a geometrically stable orientation point model is designed by reasonably arranging the orientation points, so as to achieve the best balance between accuracy and stability. For example, the orientation point model is a cube frame structure, such as Figure 2 As shown, the orientation point model of the cube frame structure includes a first crossbar 101, a second crossbar 102, a third crossbar 103, a fourth crossbar 104, a fifth crossbar 105, a sixth crossbar 106, a seventh crossbar 107, an eighth crossbar 108, a ninth crossbar 109, a tenth crossbar 110, an eleventh crossbar 111, a first vertical bar 112, a second vertical bar 113, a third vertical bar 114 and a fourth vertical bar 115. The first crossbar 101, the second crossbar 102, the third crossbar 103 and the fourth crossbar 104 constitute the bottom surface of the cube frame, the fifth crossbar 105, the sixth crossbar 106, the seventh crossbar 107 and the eighth crossbar 108 constitute the top surface of the cube frame, and the first crossbar 101, the fifth crossbar 105, the sixth crossbar 106, the seventh crossbar 107 and the eighth crossbar 108 constitute the top surface of the cube frame. 05, the first vertical rod 112 and the second vertical rod 113 and the second cross bar 102, the sixth cross bar 106, the second vertical rod 113 and the third vertical rod 114 and the third cross bar 103, the seventh cross bar 107, the third vertical rod 114 and the fourth vertical rod 115 and the fourth cross bar 104, the eighth cross bar 108, the first vertical rod 112 and the fourth vertical rod 115 respectively constitute the four side faces of the cube frame, the ninth cross bar 109 is connected between the midpoint of the fifth cross bar 105 and the midpoint of the seventh cross bar 107, the tenth cross bar 110 is connected between the midpoint of the third vertical rod 114 and the midpoint of the fourth vertical rod 115, and the eleventh cross bar 111 is connected between the midpoint of the fourth vertical rod 115 and the midpoint of the first vertical rod 112.

[0043] The orientation point model of the present invention is not limited to the above-mentioned cube frame structure, and other regular polyhedron frame structures can also be used as long as the geometric stability requirements are met.

[0044] The material of the directional point model can be silicon carbide composite materials, titanium alloy materials, Invar alloy materials or carbon fiber 3D printing materials.

[0045] Invar (Fe-Ni alloy) material: extremely low thermal expansion coefficient (~1×10⁻ 6 / °C), suitable for precision optics and metrological instrument structures. Because its material is relatively soft, the processing deformation is large, and it is easy to generate processing stress during cutting, which affects the accuracy. Therefore, the directional point model can be processed by welding or precision casting, but the directional point model with more complex shapes still needs subsequent fine processing.

[0046] Titanium alloy (Ti-6Al-4V) material: lighter than steel, more rigid, corrosion-resistant, suitable for high-precision instrument frames. Due to its high material strength, it can be used for integrated processing of directional point models using diamond tools or laser cutting.

[0047] Carbon fiber 3D printing materials (metal laser melting L-PBF, electron beam melting EBM): integrated manufacturing of directional point models is achieved through 3D printing.

[0048] Silicon carbide composite material (C / SiC): It is more resistant to high temperatures and has better dimensional stability than pure carbon fiber. It can be processed in one piece using diamond tools or laser cutting for directional point models.

[0049] The selection of orientation points should avoid being concentrated on a certain face or area of ​​the regular polyhedron framework structure, and should cover the angle areas between various planes as much as possible, so that these angle faces have geometric constraints and provide more dimensions.

[0050] S3: Install a reflective component at each orientation point, measure the three-dimensional coordinates of each reflective component using a metrology-grade spatial posture measurement device, and set up at least three measuring stations. Place a laser rangefinder at each measuring station, and use each laser rangefinder to measure the distance between each reflective component.

[0051] The distance between the reflective component and the measuring station is measured by a laser distance measuring instrument. The laser distance measuring instrument adopts a laser tracker, a laser interferometer or a laser tracking interferometer. When the laser distance measuring instrument adopts a laser tracker, the angle weight of the laser tracker is turned off, and the distance between it and each reflective component is measured by the precise distance measurement function of the laser tracker. At this time, the reflective component adopts a target ball (SMR, Spherically Mounted Retroreflector) dedicated to the laser tracker system; when the laser distance measuring instrument adopts a laser tracking interferometer, the reflective component adopts a cat's eye retroreflector (CER, Cat's Eye Retroreflector) dedicated to the laser tracking interferometer system. When the laser distance measuring instrument adopts a laser interferometer, the reflective component adopts a plane reflector, a corner cube prism, a right-angle prism or a cat's eye retroreflector dedicated to the laser interferometer.

[0052] The accuracy of laser interferometers can usually reach nanometer or submicron levels, which are suitable for high-precision distance measurement. However, the measurement range of laser interferometers is usually small, usually within a few meters (such as 1 meter to 5 meters), so it is not suitable for large-scale spatial positioning measurement, but only for small-scale spatial positioning measurement. The present invention uses a laser tracker or a laser tracking interferometer when performing large-scale spatial positioning measurement, and uses a laser interferometer when performing small-scale spatial positioning measurement.

[0053] Take six orientation points as an example, Figure 2 As shown, each orientation point corresponds to a reflection component, and the six reflection components are the first reflection component 11, the second reflection component 12, the third reflection component 13, the fourth reflection component 14, the fifth reflection component 15, and the sixth reflection component 16. The first reflection component 11 is arranged at the intersection of the seventh crossbar 107 and the eighth crossbar 108, the second reflection component 12 is arranged at the midpoint of the eleventh crossbar 111, the third reflection component 13 is arranged at the midpoint of the tenth crossbar 110, the fourth reflection component 14 is arranged at the midpoint of the ninth crossbar 109, and the fifth reflection component 15 and the sixth reflection component 16 are arranged at both ends of the first crossbar 101. That is, the six orientation points are distributed on a cube frame.

[0054] If the sixth reflection component 16 is arranged near the top surface of the cube, the plane formed by the first reflection component 11, the second reflection component 12, and the sixth reflection component 16 is redundant with the plane formed by the first reflection component 11, the second reflection component 12, and the third reflection component 13. Therefore, the sixth reflection component 16 is arranged near the bottom surface of the cube to expand more dimensions.

[0055] The first reflective component 11, the second reflective component 12, the third reflective component 13, the fourth reflective component 14, the fifth reflective component 15, and the sixth reflective component 16 are respectively installed on the cube frame through reflective component seats. The reflective component seats can be integrally processed with the cube frame, or the reflective component seats can be fixed on the cube frame after the cube frame is processed.

[0056] The metrology-grade spatial posture measurement device uses a three-dimensional coordinate measuring machine to measure the three-dimensional coordinates of the first reflection component 11, the second reflection component 12, the third reflection component 13, the fourth reflection component 14, the fifth reflection component 15, and the sixth reflection component 16. Since the three-dimensional coordinate measuring machine has extremely high measurement accuracy, it is possible to obtain high-precision three-dimensional coordinates of the reflection component.

[0057] S4: Using the three-dimensional coordinates of each reflective component and the distance between each laser ranging instrument and each reflective component, the three-dimensional coordinates of each measuring station are calculated by a spatial resection method based on the least squares method.

[0058] The 3D coordinates of each station are calculated in the same way. Figure 3 The laser ranging instrument 21) is used as an example for explanation.

[0059] Let the three-dimensional coordinates of the first reflection component be , the three-dimensional coordinates of the remaining reflection components are , the three-dimensional coordinates of a station point are , then the distance between the first reflector and the laser distance measuring instrument corresponding to the station point is for:

[0060] The distance between the remaining reflective components and the laser distance measuring instrument corresponding to the measuring station for:

[0061] Decomposing equation (1) and equation (2) yields:

[0062]

[0063] Combining equation (3) and equation (4) we get:

[0064] By rearranging formula (5), we can obtain:

[0065] Formula (6) is transformed into an overdetermined system of equations:

[0066] 3D coordinates of the station point The unknown number is solved by using the spatial intersection method to obtain the three-dimensional coordinates of the measuring station. The spatial intersection formed by the reflection component and the laser ranging instrument is as follows: Figure 3 As shown in the figure, since the solution process of the resection method involves multiple known orientation points and their measurement data, the use of the least squares method helps to effectively reduce the error in the measurement and ensure that the three-dimensional coordinates of the station point finally obtained have high accuracy.

[0067] like Figure 4 As shown, when four or more laser distance measuring instruments are used, all laser distance measuring instruments are combined with all reflection components to form a side measurement network adjustment, which can further improve the three-dimensional coordinate accuracy of the measuring station.

[0068] S5: Install the reflective component on the target point, use each laser ranging instrument to measure the distance between each and the target point, and combine it with the three-dimensional coordinates of each measuring station, and calculate it through the spatial forward intersection method based on the least squares method to obtain the three-dimensional coordinates of the target point.

[0069] like Figure 5 As shown in the figure, the camera adjustment device is taken as the target 3, and the three vertices of the adjustment device are taken as the target point 31. The three-dimensional coordinates of the target point 31 are calculated respectively. Since the calculation method is the same, only the three-dimensional coordinates of the target point 31 are calculated. Figure 5 The target point 31 shown is used as an example for detailed description.

[0070] Assume the three-dimensional coordinates of the first station point are , the three-dimensional coordinates of the reflection components of the other station points are , the three-dimensional coordinates of the target point are , then the distance between the first measuring station and the target point for:

[0071] The distance between the remaining measuring stations and the laser distance measuring instrument corresponding to the target point for:

[0072] Decomposing equation (8) and equation (9) we can get:

[0073]

[0074] Combining equation (10) and equation (11), we get:

[0075] By rearranging formula (12), we can obtain: ; Assume that there are four measuring stations and the three-dimensional coordinates of the first measuring station are The three-dimensional coordinates of the other measuring stations are ~ , formula (13) is transformed into a system of equations:

[0076] Due to the three equations and three unknowns, the three-dimensional coordinates of the target point can be directly calculated. Solve and obtain the three-dimensional coordinates of the target point.

[0077] When the number of measuring stations is four or more, Equation (13) becomes an overdetermined system of equations and is solved by the least squares method.

[0078] The measurement method provided by the present invention utilizes the directional point model of spatial multi-distance constraints and the high-precision distance measurement technology of the laser distance measuring instrument to achieve high-precision three-dimensional positioning measurement, simplify the process, improve the measurement efficiency, and reduce the operation complexity. The measurement method is simple and efficient to operate, and is suitable for application scenarios with high-precision positioning requirements such as aerospace, precision manufacturing, and optical system adjustment, and has a strong value for promotion and application.

[0079] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0080] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model, characterized in that: The steps include: S1: Design a geometrically stable directional point model based on the uniform distribution principle and polygon stability principle; S2: Process the designed orientation point model, and reasonably arrange the orientation points on the processed orientation point model to ensure that each laser ranging instrument can observe all orientation points; S3: Install a reflective component at each orientation point, measure the three-dimensional coordinates of each reflective component using a metrology-grade spatial posture measurement device, and arrange at least three measuring stations, place a laser rangefinder at each measuring station, and use each laser rangefinder to measure the distance between each and each reflective component; S4: using the three-dimensional coordinates of each reflective component and the distance between each laser ranging instrument and each reflective component, a spatial resection method based on the least squares method is used to calculate and obtain the three-dimensional coordinates of each measuring station; S5: Install the reflective component on the target point, use each laser ranging instrument to measure the distance between each and the target point, and combine it with the three-dimensional coordinates of each measuring station, and calculate it through the spatial forward intersection method based on the least squares method to obtain the three-dimensional coordinates of the target point.

2. The method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model according to claim 1 is characterized in that: In step S4, the three-dimensional coordinates of the first reflection component are set to , the three-dimensional coordinates of the remaining reflection components are , the three-dimensional coordinates of a station point are , then the distance between the first reflector and the laser distance measuring instrument corresponding to the station point is for: The distance between the remaining reflective components and the laser distance measuring instrument corresponding to the measuring station for: Decomposing equation (1) and equation (2) yields: Combining equation (3) and equation (4) we get: After rearranging formula (5), we can get: Assume that the number of reflection components is six, and the three-dimensional coordinates of the first reflection component are , the three-dimensional coordinates of the remaining reflection components are ~ , formula (6) is transformed into an overdetermined system of equations: The three-dimensional coordinates of the measuring station are obtained by the least squares method Solve and obtain the three-dimensional coordinates of the measuring station.

3. The method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model according to claim 1 is characterized in that: In step S5, the three-dimensional coordinates of the first measuring station are set to , the three-dimensional coordinates of the reflection components of the other station points are , the three-dimensional coordinates of the target point are , then the distance between the first measuring station and the target point for: The distance between the remaining measuring stations and the laser distance measuring instrument corresponding to the target point for: Decomposing equation (8) and equation (9) we can get: Combining equation (10) and equation (11), we get: By rearranging formula (12), we can obtain: ； Assume that there are four measuring stations and the three-dimensional coordinates of the first measuring station are The three-dimensional coordinates of the other measuring stations are ~ , formula (13) is transformed into a system of equations: The three-dimensional coordinates of the target point Solve and obtain the three-dimensional coordinates of the target point.

4. The method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model according to claim 1 is characterized in that: The orientation point model is a cube frame, including eleven crossbars and four vertical bars. The first crossbar, the second crossbar, the third crossbar, and the fourth crossbar constitute the bottom surface of the cube frame, the fifth crossbar, the sixth crossbar, the seventh crossbar, and the eighth crossbar constitute the top surface of the cube frame, the first crossbar, the fifth crossbar, the first vertical bar and the second vertical bar, the second crossbar, the sixth crossbar, the second vertical bar and the third vertical bar, the third crossbar, the seventh crossbar, the third vertical bar and the fourth vertical bar, the fourth crossbar, the eighth crossbar, the first vertical bar and the fourth vertical bar respectively constitute the four side surfaces of the cube frame, the ninth crossbar is connected between the midpoint of the fifth crossbar and the midpoint of the seventh crossbar, the tenth crossbar is connected between the midpoint of the third vertical bar and the midpoint of the fourth vertical bar, and the eleventh crossbar is connected between the midpoint of the fourth vertical bar and the midpoint of the first vertical bar.

5. The method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model according to claim 4 is characterized in that: The material of the directional point model is silicon carbide composite material, titanium alloy material, Invar alloy material or carbon fiber 3D printing material.

6. The method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model according to claim 4 is characterized in that: There are six orientation points, which are respectively arranged at two ends of the first crossbar, the middle points of the ninth crossbar, the tenth crossbar, the eleventh crossbar, and the intersection of the seventh crossbar and the eighth crossbar.

7. The method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model according to claim 1, characterized in that: The metrology-grade spatial posture measurement equipment is a three-coordinate measuring machine.

8. The method for improving the three-dimensional positioning accuracy of a laser ranging instrument based on a directional point model according to claim 1, characterized in that: The laser distance measuring instrument is a laser tracker, a laser interferometer or a laser tracking interferometer. When the laser distance measuring instrument is a laser tracker, the reflection component adopts a target ball specially used for the laser tracker; when the laser distance measuring instrument is a laser tracking interferometer, the reflection component adopts a cat's eye retro-reflector specially used for the laser tracking interferometer; when the laser distance measuring instrument is a laser interferometer, the reflection component adopts a plane reflector, a corner cube prism, a right-angle prism or a cat's eye retro-reflector specially used for the laser interferometer.

Images