Area measuring device for geographic information planning

Abstract

The invention discloses an area measuring device for geographic information planning, and relates to the technical field of laser surveying and mapping instruments, the area measuring device comprises a base mounted on a tripod and a machine body, a cavity is formed in the machine body, a mounting ball is mounted in the cavity, a mounting cavity is formed in the mounting ball, a laser transmitter is fixedly mounted in the mounting cavity, and the laser transmitter is connected with the base. And a symmetrical optical bridge assembly matched with the laser transmitter is mounted in the mounting cavity. The device has the advantages that laser can be divided into a measuring light beam and a reference light beam, a real-time differential reference system is formed, environmental interference is effectively counteracted, the measuring precision is remarkably improved, the coverage range of the measuring light beam can be accurately adjusted, frequent movement of a machine body does not need to be avoided, the working efficiency is greatly improved, in addition, the mounting ball can be automatically kept in a vertical state, and the working efficiency is improved. The problems of low manual leveling speed and large residual error are solved, and the accuracy is further ensured while the measurement convenience is improved.

Description

Technical Field

[0001] This invention relates to the field of laser mapping instrument technology, and in particular to an area measurement device for geographic information planning. Background Technology

[0002] Geographic information planning area measurement devices refer to professional instruments that use optical principles to quantitatively measure surface areas. They acquire spatial coordinate data of boundary points and use geometric algorithms to calculate the projected area. They have wide application needs in fields such as land surveying, farmland management, engineering planning and municipal construction. With the development of optoelectronic technology, measuring instruments based on laser ranging technology have gradually become the market mainstream due to their non-contact and high-precision characteristics.

[0003] The current mainstream technical solutions mainly include two types: handheld laser rangefinders and stationary total stations. Handheld devices measure the slant distance between the operator and multiple boundary points, combine the data from the built-in tilt sensor to calculate the horizontal distance, and then use the polygon area formula to complete the calculation. Stationary devices establish a station coordinate system, use a visible laser pointer to assist aiming, collect the three-dimensional coordinate data of boundary feature points point by point, and finally calculate the projected area using the triangulation method.

[0004] However, both of the above measuring devices have the following problems: Measurement using a single laser beam lacks a real-time reference benchmark. Under complex lighting conditions, the beam shape is easily affected by atmospheric disturbances, causing dispersion and drift in the center of the laser spot. Furthermore, when encountering vegetation cover or semi-transparent obstacles, some laser beams penetrate the gaps and reach non-target surfaces, resulting in jumps in ranging data and affecting the accuracy of the measurement results. Furthermore, the leveling of existing measuring devices relies entirely on the operator's experience, often requiring repeated adjustments in sloping environments. Additionally, the rigid connection of the laser emitter lacks attitude sensing and automatic adjustment capabilities, making leveling difficult and resulting in poor horizontal maintenance.

[0005] Therefore, it is necessary to design an area measurement device for geographic information planning. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an area measurement device for geographic information planning, which solves the problems mentioned in the background section.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A geographic information planning area measurement device includes a base mounted on a tripod and a main body. The main body has a cavity, and a mounting ball is installed within the cavity. The mounting ball has a mounting chamber, and a laser emitter is fixedly installed within the mounting chamber. A symmetrical optical bridge assembly, which cooperates with the laser emitter, is installed within the mounting chamber. The symmetrical optical bridge assembly is used to split the laser emitted by the laser emitter into two beams of equal intensity. The symmetrical optical bridge assembly includes a semi-transparent mirror and a reflector. A deflection assembly, which cooperates with the reflector, is installed within the mounting ball. The deflection assembly is used to adjust the angle of the beam reflected by the reflector. The machine body is equipped with a flexible support component that cooperates with the mounting ball. The flexible support component is used to keep the mounting ball in a horizontal state within the machine body.

[0008] Furthermore, the mounting ball has a through groove communicating with the mounting cavity, and the body has a through groove communicating with the cavity, with the through groove and the through groove being positioned corresponding to each other. A partition is fixedly installed in the through groove, and the partition is used to separate the light beam passing through the semi-transparent and semi-reflective mirror from the light beam reflected by the reflector.

[0009] Furthermore, the deflection assembly consists of a rotating shaft, a servo motor, and a differential mechanism. The rotating shaft is fixedly mounted on the reflector and is rotatably connected to the mounting ball. The servo motor is fixedly mounted inside the mounting ball, and the differential mechanism is installed between the output end of the servo motor and the rotating shaft.

[0010] Furthermore, the differential mechanism consists of a pinion, a round shaft, a large gear, and a differential chain drive structure. The pinion is fixedly mounted on the output end of the servo motor. The round shaft is rotatably mounted inside the mounting ball. The large gear is fixedly mounted on the round shaft and meshes with the pinion. The differential chain drive structure is installed between the round shaft and the rotating shaft. The diameter and number of teeth of the large gear are both larger than those of the pinion.

[0011] Furthermore, the differential chain drive structure consists of a sprocket one, a chain one, and a sprocket two. The sprocket one is fixedly mounted on a round shaft, the sprocket two is fixedly mounted on a rotating shaft, and the chain one is installed between the sprocket one and the sprocket two, with the diameter of the sprocket one being smaller than the diameter of the sprocket two.

[0012] Furthermore, a connecting shaft is fixedly installed on the top of the rotating shaft, a fixed shaft is rotatably installed inside the mounting ball, a fixed block is fixedly installed at one end of the fixed shaft located in the through groove, and a focusing sleeve that cooperates with the reflector is fixedly installed at the bottom of the fixed block. A constant speed chain drive structure is installed between the fixed shaft and the connecting shaft.

[0013] Furthermore, the flexible support assembly consists of a fixed ring, a mounting ring, and two arc-shaped plates. The fixed ring is rotatably mounted in the cavity along the horizontal plane, and the two arc-shaped plates are fixedly mounted on the inner wall of the fixed ring. The mounting ring is mounted between the two arc-shaped plates and can slide between the two arc-shaped plates along the vertical plane.

[0014] Furthermore, two arc-shaped grooves are formed on the side wall of the cavity, two sliders that slide in cooperation with the corresponding arc-shaped grooves are fixedly installed on the side wall of the fixing ring, a T-shaped block is fixedly installed on the side wall of the mounting ring, and a T-shaped groove that slides in cooperation with the T-shaped block is formed on the arc plate.

[0015] Furthermore, a weighted ball is fixedly installed at the bottom of the mounting ball, a groove is provided on the side wall of the cavity to cooperate with the weighted ball, a light-shielding sleeve is fixedly installed on the body and the light-shielding sleeve corresponds to the position of the through groove, and a connecting block adapted to the base is fixedly installed at the bottom of the body.

[0016] Compared with existing technologies, the advantages of this invention are: 1: By using a semi-transparent and semi-reflective mirror to precisely split a laser beam into a measurement beam and a reference beam of equal intensity, a real-time reference system can be provided. This effectively identifies and cancels common interference components, significantly reducing the error rate and uncertainty of the measurement results, and effectively improving the accuracy of area measurement.

[0017] 2: Through the design of the deflection component, the angle of the reflector can be adjusted with high precision, so that the beam emitted by it can measure the specified position. When measuring irregular plots or areas with multiple obstacles, there is no need to move the machine body and perform leveling multiple times, which effectively improves work efficiency and avoids measurement errors introduced by moving the machine body.

[0018] 3: Through the design of the flexible support components, when the machine body tilts due to uneven ground, the weighted ball at the bottom of the mounting ball generates a strong restoring torque under the action of gravity, which enables the mounting ball to automatically find and stabilize in the vertical direction. This effectively solves the problems of slow speed, large residual error, and high requirements for operator experience that traditional equipment relies on manual leveling, and further improves the accuracy of measurement work.

[0019] In summary, this invention can divide the laser into a measurement beam and a reference beam to form a real-time differential reference system, effectively counteracting environmental interference and significantly improving measurement accuracy. Furthermore, it allows for precise adjustment of the coverage area of ​​the measurement beam without frequent machine movement, greatly improving work efficiency. In addition, it enables the mounting ball to automatically maintain a vertical state, solving the problems of slow manual leveling and large residuals. While improving the convenience of measurement, it further ensures accuracy. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of an area measurement device for geographic information planning proposed in this invention; Figure 2 for Figure 1 A structural diagram from another perspective; Figure 3 for Figure 2 Enlarged schematic diagram of the structure in the middle body; Figure 4 for Figure 3 The right view; Figure 5 for Figure 4 Schematic diagram of the structure of surface AA; Figure 6 for Figure 4 Schematic diagram of the structure of the middle BB surface; Figure 7 for Figure 6 Enlarged structural diagram of section C; Figure 8 for Figure 3 A schematic diagram of the structure after the body has been removed; Figure 9 for Figure 8 A schematic diagram of the mounting ball and its external structure; Figure 10 for Figure 8 Schematic diagram of the internal structure of the sphere in the middle; Figure 11 for Figure 10 A structural diagram from another perspective; Figure 12 for Figure 11 Enlarged structural diagram of section D.

[0021] In the diagram: 1. Tripod, 2. Base, 3. Body, 4. Light-shielding sleeve, 5. Connecting block, 6. Cavity, 7. Mounting ball, 8. Mounting cavity, 9. Laser emitter, 10. Semi-transparent mirror, 11. Reflector, 12. Through slot, 13. Through groove, 14. Partition, 15. Rotating shaft, 16. Servo motor, 17. Pinion, 18. Large gear, 19. Differential chain drive structure, 20. Connecting shaft, 21. Fixed shaft, 22. Fixed block, 23. Focusing sleeve, 24. Constant speed chain drive structure, 25. Fixed ring, 26. Slider, 27. Arc groove, 28. Arc plate, 29. T-slot, 30. T-block, 31. Mounting ring, 32. Weighted ball. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Reference Figures 1-12 A geographic information planning area measurement device includes a base 2 mounted on a tripod 1 and a body 3. A connecting block 5 adapted to the base 2 is fixedly installed at the bottom of the body 3. The tripod 1 is an existing support component with a leveling function, which can be used to level the base 2, thereby improving the horizontality and stability of the body 3 mounted on it. The specific structure is not described here.

[0025] A cavity 6 is provided inside the body 3, and a mounting ball 7 is installed inside the cavity 6. A mounting cavity 8 is provided inside the mounting ball 7, and a laser emitter 9 is fixedly installed inside the mounting cavity 8. The laser emitter 9 is preferably a semiconductor laser with an output wavelength in the visible light or near-infrared band, such as 635nm or 1550nm. It has the characteristics of stable power, small size and long life. The laser beam emitted by it is the original reference for all subsequent measurements. The specific structure and working principle of the laser emitter 9 will not be described here. The cooperation between the mounting ball 7 and the cavity 6 allows the laser emitter 9 located inside the mounting ball 7 to have a larger angle adjustment space, which makes it easier to keep the laser emitter 9 in a horizontal state.

[0026] The mounting cavity 8 houses a symmetrical optical bridge assembly that works in conjunction with the laser emitter 9. This assembly splits the laser emitted by the laser emitter into two beams of equal intensity. The symmetrical optical bridge assembly includes a semi-transparent mirror 10 and a reflector 11. The semi-transparent mirror 10 is made of K9 optical glass and coated with a beam-splitting film. This film uses dielectric films with different refractive indices (such as silicon dioxide and titanium dioxide). The laser emitted by the laser emitter 9 is incident on the semi-transparent mirror 10 at a 45° angle, with part of the light source projected and part reflected. The reflector 11 is coated with a high-reflectivity dielectric film. The light reflected from the semi-transparent mirror 10 is incident on the reflector 11 and then reflected out, thus forming two beams of equal intensity. Initially, the reflector 11 is horizontal to the semi-transparent mirror 10. At this point, the two beams are horizontal to each other. During area measurement, the two beams can serve as a real-time reference, preventing beam dispersion caused by atmospheric disturbances. This also improves the detection effect of the beam on the target surface and increases the accuracy of the measurement results.

[0027] The mounting ball 7 has a through groove 12 that communicates with the mounting cavity 8. The body 3 has a through groove 13 that communicates with the cavity 6, and the through groove 13 corresponds to the position of the through groove 12. A light-shielding sleeve 4 is fixedly installed on the body 3, and the light-shielding sleeve 4 corresponds to the position of the through groove 13. A partition 14 is fixedly installed inside the through groove 13. The partition 14 is used to separate the light beam passing through the semi-transparent and semi-reflective mirror 10 and the light beam reflected by the reflector 11, forming two independent optical channels and avoiding cross-contamination at the outlet.

[0028] The mounting ball 7 contains a deflection assembly that works in conjunction with the reflector 11. The deflection assembly is used to adjust the angle of the beam reflected by the reflector 11. When the angle of the reflector 11 changes, the angle of its emitted beam also changes. Therefore, when the body 3 remains stationary, the change in the angle of the reflector 11 will change the position of its emitted beam. This change can then be used to measure reference objects at different positions, thereby reducing the movement frequency of the body 3 and eliminating the need for readjustment. This effectively improves work efficiency and avoids the problem of errors in the detection results caused by frequent movement of the body 3.

[0029] The deflection assembly consists of a rotating shaft 15, a servo motor 16, and a differential mechanism. The rotating shaft 15 is fixedly mounted on the reflector 11 and is rotatably connected to the mounting ball 7. The servo motor 16 is fixedly mounted inside the mounting ball 7. The differential mechanism is installed between the output end of the servo motor 16 and the rotating shaft 15. The servo motor 16 is a miniature servo motor of model MGX1MB01A010AS, which can rotate in two different directions during operation. The specific structure and working principle are not described here.

[0030] The differential mechanism consists of a pinion 17, a round shaft, a large gear 18, and a differential chain drive structure 19. The pinion 17 is fixedly mounted on the output end of the servo motor 16. The round shaft is rotatably mounted inside the mounting ball 7. The large gear 18 is fixedly mounted on the round shaft and meshes with the pinion 17. The differential chain drive structure 19 is installed between the round shaft and the rotating shaft 15. When the servo motor 16 is working, it drives the pinion 17 to rotate. The meshing effect of the pinion 17 and the large gear 18 causes the round shaft to rotate simultaneously. Consequently, under the action of the differential chain drive structure 19, the rotating shaft 15 rotates simultaneously, driving the reflector 11. An angular deflection occurs within the mounting cavity 7, adjusting the angle of the beam emitted from it. When the beam emitted from the reflector 11 is horizontal with the beam transmitted through the semi-transparent mirror 10, the measurement results of the two beams can be used for mutual reference. When the angle of the beam emitted from the reflector 11 changes, it can be used in conjunction with the beam transmitted through the semi-transparent mirror 10 to simultaneously measure two different points, which can improve measurement efficiency and eliminate the need for frequent movement of the machine body 3. In addition, the inherent small tension of the chain drive can effectively eliminate the backlash that may exist in the gear pair, ensuring the absolute accuracy and repeatability of the angle positioning of the reflector 11.

[0031] The diameter and number of teeth of the large gear 18 are both larger than those of the small gear 17. The differential chain drive structure 19 consists of a sprocket one, a chain one, and a sprocket two. Sprocket one is fixedly mounted on a round shaft, and sprocket two is fixedly mounted on a rotating shaft 15. Chain one is installed between sprocket one and sprocket two, and the diameter of sprocket one is smaller than that of sprocket two. Through the design of the diameter and number of teeth of the large gear 18 and the small gear 17, the round shaft rotates at a lower speed when the servo motor 16 is working. The design of the differential chain drive structure 19 further reduces the transmission ratio of the round shaft to the rotating shaft 15, thereby making the deflection speed of the reflector 11 slower, which facilitates fine angle adjustment and avoids the problem that the beam emitted from the reflector 11 is difficult to align with the required measurement point due to excessively fast deflection speed. The overall control difficulty is relatively small.

[0032] A connecting shaft 20 is fixedly mounted on the top of the rotating shaft 15. A fixed shaft 21 is rotatably mounted inside the mounting ball 7. A fixing block 22 is fixedly mounted on one end of the fixed shaft 21 located in the through groove 12. A focusing sleeve 23 that cooperates with the reflector 11 is fixedly mounted on the bottom of the fixing block 22. The inner wall of the focusing sleeve 23 is smooth and coated with an enhanced reflection film, which can collect and constrain the laser beam reflected from the reflector 11, effectively suppress beam divergence, cut off sidelobe energy, and make the emitted light spot more concentrated and the energy density higher, so as to maintain a good signal-to-noise ratio even when measuring at a distance. A constant velocity chain is installed between the fixed shaft 21 and the connecting shaft 20. The moving structure, the constant velocity chain drive structure, consists of chain two and two sprockets three. The two sprockets three are fixedly installed on the connecting shaft 20 and the fixed shaft 21, respectively. Chain two is installed between the two sprockets three. Through the design of the constant velocity chain drive structure, when the connecting shaft 20 rotates, it can drive the fixed shaft 21 to rotate at the same time. At this time, the focusing sleeve 23, which is fixedly installed at the bottom of the fixed shaft 21 by the fixing block 22, will also deflect at the same angle. This ensures that the focusing sleeve 23 always keeps the beam emitted from the reflector 11 horizontal, which can accurately guide the beam and play the role of constraining the beam and reducing divergence and stray light.

[0033] The body 3 is equipped with a flexible support component that cooperates with the mounting ball 7. The flexible support component is used to keep the mounting ball 7 in a horizontal state within the body 3. A weighted ball 32 is fixedly installed at the bottom of the mounting ball 7. The weighted ball 32 is made of high-density material. The side wall of the cavity 6 is provided with a groove that cooperates with the weighted ball 32. Under the action of gravity, the weighted ball 32 always tends to move downward, thereby applying a force to keep the mounting ball 7 in a horizontal position.

[0034] The flexible support assembly consists of a fixed ring 25, a mounting ring 31, and two arc-shaped plates 28. The fixed ring 25 is rotatably mounted in the cavity 6 along the horizontal plane. The two arc-shaped plates 28 are fixedly mounted on the inner wall of the fixed ring 25. The mounting ring 31 is mounted between the two arc-shaped plates 28 and can slide between the two arc-shaped plates 28 along the vertical plane. When the machine body 3 is not placed evenly or vibrates due to external vibration, the centering force applied by the weighted ball 32 to the mounting ball 7 will cause the mounting ball 7 to automatically move in the horizontal or vertical plane within the cavity 6, thereby maintaining centering and ensuring the horizontal placement of the laser emitter 9 inside, thus improving the accuracy of the detection results.

[0035] Two arc-shaped grooves 27 are formed on the side wall of the cavity 6. Two sliders 26 are fixedly installed on the side wall of the fixing ring 25, which slide in accordance with the corresponding arc-shaped grooves 27. The cooperation between the sliders 26 and the arc-shaped grooves 27 allows the fixing ring 25 to rotate horizontally within the body 3. A T-shaped block 30 is fixedly installed on the side wall of the mounting ring 31. A T-shaped groove 27 is formed on the arc plate 28, which slides in accordance with the T-shaped block 30. The cooperation between the T-shaped block 30 and the T-shaped groove 27 allows the mounting ring 31 to rotate vertically on the fixing ring 25. At the same time, when the fixing ring 25 rotates horizontally, the limiting effect of the T-shaped block 30 and the T-shaped groove 27 in the horizontal direction will drive the mounting ring 31 to rotate simultaneously, so that the mounting ball 7 can rotate in both the horizontal and vertical planes.

[0036] When the terrain is uneven or the body 3 is tilted due to external disturbance, the weighted ball 32 always tends to move downward under the action of gravity. This tendency is transmitted to the mounting ring 31 through the mounting ball 7, forcing the mounting ring 31 to slide in the T-groove 29 of the arc plate 28 through its T-block 30. At the same time, the entire fixed ring 25 can also rotate in the arc groove 27 through the slider 26. The combined motion of these two degrees of freedom (one rotational degree of freedom about the vertical axis and one rotational degree of freedom about the horizontal axis) enables the mounting ball 7 to quickly return to the stable state with the lowest center of gravity, i.e., the vertical state, in the dynamic balance of inertial force and gravitational torque.

[0037] To further clarify, the aforementioned fixed connection should be interpreted broadly unless otherwise explicitly specified and limited. For example, it may be welding, gluing, or integral molding, or other conventional methods well known to those skilled in the art.

[0038] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. An area measurement device for geographic information planning, comprising a base (2) mounted on a tripod (1) and a body (3), characterized in that: The body (3) has a cavity (6) inside, and a mounting ball (7) is installed inside the cavity (6). The mounting ball (7) has a mounting cavity (8) inside, and a laser emitter (9) is fixedly installed inside the mounting cavity (8). A symmetrical optical bridge assembly that cooperates with the laser emitter (9) is installed inside the mounting cavity (8). The symmetrical optical bridge assembly is used to split the laser emitted by the laser emitter into two beams of equal intensity. The symmetrical optical bridge assembly includes a semi-transparent and semi-reflective mirror (10) and a reflector (11). A deflection assembly that cooperates with the reflector (11) is installed inside the mounting ball (7). The deflection assembly is used to adjust the angle of the beam reflected by the reflector (11). The body (3) is equipped with a flexible support component that cooperates with the mounting ball (7). The flexible support component is used to keep the mounting ball (7) in a horizontal state within the body (3).

2. The area measurement device for geographic information planning according to claim 1, characterized in that, The mounting ball (7) has a through groove (12) that communicates with the mounting cavity (8), and the body (3) has a through groove (13) that communicates with the cavity (6). The through groove (13) and the through groove (12) are positioned opposite each other. A partition (14) is fixedly installed in the through groove (13). The partition (14) is used to separate the light beam passing through the semi-transparent mirror (10) and the light beam reflected by the mirror (11).

3. The area measurement device for geographic information planning according to claim 1, characterized in that, The deflection assembly consists of a rotating shaft (15), a servo motor (16), and a differential mechanism. The rotating shaft (15) is fixedly mounted on the reflector (11) and is rotatably connected to the mounting ball (7). The servo motor (16) is fixedly mounted inside the mounting ball (7). The differential mechanism is installed between the output end of the servo motor (16) and the rotating shaft (15).

4. The area measurement device for geographic information planning according to claim 3, characterized in that, The differential mechanism consists of a small gear (17), a round shaft, a large gear (18), and a differential chain drive structure (19). The small gear (17) is fixedly installed on the output end of the servo motor (16). The round shaft is rotatably installed in the mounting ball (7). The large gear (18) is fixedly installed on the round shaft and meshes with the small gear (17). The differential chain drive structure (19) is installed between the round shaft and the rotating shaft (15). The diameter and number of teeth of the large gear (18) are both greater than those of the small gear (17).

5. The area measurement device for geographic information planning according to claim 4, characterized in that, The differential chain drive structure (19) consists of a sprocket one, a chain one and a sprocket two. The sprocket one is fixedly installed on a round shaft, the sprocket two is fixedly installed on a rotating shaft (15), the chain one is installed between the sprocket one and the sprocket two, and the diameter of the sprocket one is smaller than the diameter of the sprocket two.

6. The area measurement device for geographic information planning according to claim 3, characterized in that, A connecting shaft (20) is fixedly installed on the top of the rotating shaft (15), and a fixed shaft (21) is rotatably installed inside the mounting ball (7). A fixed block (22) is fixedly installed at one end of the fixed shaft (21) located in the through groove (12), and a focusing sleeve (23) that cooperates with the reflector (11) is fixedly installed at the bottom of the fixed block (22). A constant speed chain drive structure is installed between the fixed shaft (21) and the connecting shaft (20).

7. The area measurement device for geographic information planning according to claim 1, characterized in that, The flexible support assembly consists of a fixed ring (25), a mounting ring (31), and two arc-shaped plates (28). The fixed ring (25) is rotatably mounted in the cavity (6) along the horizontal plane. The two arc-shaped plates (28) are fixedly mounted on the inner wall of the fixed ring (25). The mounting ring (31) is mounted between the two arc-shaped plates (28) and can slide between the two arc-shaped plates (28) along the vertical plane.

8. The area measurement device for geographic information planning according to claim 7, characterized in that, Two arc-shaped grooves (27) are provided on the side wall of the cavity (6). Two sliders (26) that slide in cooperation with the corresponding arc-shaped grooves (27) are fixedly installed on the side wall of the fixing ring (25). A T-shaped block (30) is fixedly installed on the side wall of the mounting ring (31). A T-shaped groove (27) that slides in cooperation with the T-shaped block (30) is provided on the arc plate (28).

9. The area measurement device for geographic information planning according to claim 2, characterized in that, The bottom of the mounting ball (7) is fixedly mounted with a weighted ball (32), and the side wall of the cavity (6) is provided with a groove that matches the weighted ball (32). The body (3) is fixedly mounted with a light-shielding sleeve (4), and the light-shielding sleeve (4) corresponds to the position of the through groove (13). The bottom of the body (3) is fixedly mounted with a connecting block (5) that matches the base (2).

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