GNSS field observation system based on PLC and observation method thereof

Abstract

The invention discloses a GNSS (Global Navigation Satellite System) field observation system based on a PLC (Programmable Logic Controller) and an observation method thereof. The GNSS field observation system based on the PLC comprises a control box, a mounting shell, a mounting platform, a north-seeking mechanism and a horizontal adjusting mechanism. According to the GNSS field observation system based on the PLC, GNSS data unmanned acquisition is realized by using the GNSS positioning module and the GNSS antenna; the horizontal adjusting mechanism is used for adjusting the mounting platform under the control of the PLC control unit, so that the mounting platform is in a horizontal state, and working conditions are provided for the GNSS positioning module and the GNSS antenna; the north-seeking mechanism is used for driving the pipe shaft to rotate, so that a north-seeking mark of the GNSS antenna directly faces the north, and the accuracy of acquired GNSS data is ensured; the distance measuring sensor is used for detecting the distance between the GNSS antenna and the inner bottom surface of the mounting shell, and data is uploaded to a remote control center, so that the accuracy of GNSS data is ensured.

Description

Technical Field

[0001] The present invention relates to a field observation system, in particular to a PLC-based GNSS field observation system and an observation method thereof. Background Art

[0002] The degree of standardization of GNSS field observation process directly affects the quality of observation data. In addition to the observation environment, the quality of GNSS data observation is directly affected by the antenna horizontality, north pointing and antenna height measurement. At present, GNSS field observations are carried out according to the requirements of the land state network, using a special base for manual zeroing, a handheld compass to find the north and a handheld ruler to measure the antenna height. Manual operation will inevitably introduce certain errors and the operation is relatively cumbersome. Under this premise, a GNSS field observation system based on PLC is designed. Summary of the invention

[0003] Purpose of the invention: To provide a PLC-based GNSS field observation system and an observation method thereof, so as to reduce the error introduced by manual operation and improve the automation level of GNSS field observation.

[0004] Technical solution: The PLC-based GNSS field observation system provided by the present invention includes a control box, an installation shell, an installation platform, a north-seeking mechanism and a horizontal adjustment mechanism; a PLC control unit and a battery for power supply are installed in the installation shell; a wireless communication module and a memory electrically connected to the PLC control unit are installed in the control box; the horizontal adjustment mechanism is installed in the installation shell; the installation platform is installed on the horizontal adjustment mechanism, and the horizontality of the installation platform is adjusted by the horizontal adjustment mechanism; an observation hole is provided on the installation platform; a positioning tube is docked on the observation hole; a pipe shaft penetrating the top of the installation shell is rotatably installed on the positioning tube; a GNSS antenna electrically connected to the PLC control unit through a GNSS positioning module is installed in the pipe shaft; the north-seeking mechanism is installed in the installation shell, and is used to drive the pipe shaft to rotate so that the north-pointing mark of the GNSS antenna faces north; a distance measuring sensor electrically connected to the PLC control unit is installed in the installation shell, and is used to detect the distance between the GNSS antenna and the bottom surface of the installation shell; the north-seeking mechanism and the horizontal adjustment mechanism are both driven and controlled by the PLC control unit.

[0005] Furthermore, the mounting shell includes a protective cover and a base plate; a positioning ring installed at the lower opening of the protective cover is fixed on the base plate; an extension hole for the pipe axis to pass through is provided on the top of the protective cover; and a handle is installed on the top of the protective cover.

[0006] Furthermore, a retaining ring is connected to the upper opening of the extension hole; and a flexible shielding bucket for covering the retaining ring is arranged on the bottom of the GNSS antenna.

[0007] Furthermore, a mounting plate is arranged on the positioning ring; the control box is mounted on the mounting plate; and an avoidance notch for avoiding the control box is arranged on the lower edge of the protective cover.

[0008] Furthermore, a key panel and a display screen electrically connected to the PLC control unit are installed on the control box.

[0009] Furthermore, the north-seeking mechanism includes a north-seeking gyroscope and a rotation drive motor; the rotation drive motor is installed on the positioning tube, drives the tube shaft to rotate through a worm gear transmission pair, and is electrically connected to the PLC control unit through a rotation drive circuit; the north-seeking gyroscope is installed on the inner bottom surface of the mounting shell, and is electrically connected to the PLC control unit.

[0010] Furthermore, the horizontal adjustment mechanism includes a transverse adjustment unit and a longitudinal adjustment unit; the transverse adjustment unit is installed in the installation shell, and the installation platform is installed on the transverse adjustment unit, and the transverse adjustment unit adjusts the height difference between the left and right sides of the installation platform; the longitudinal adjustment unit is installed on the transverse adjustment unit, and is used to adjust the height difference between the front and rear sides of the installation platform; the transverse adjustment unit and the longitudinal adjustment unit are both driven and controlled by the PLC control unit; a dual-axis inclination sensor electrically connected to the PLC control unit is installed on the upper side of the installation platform.

[0011] Further, the lateral adjustment unit includes a lateral adjustment drive tube, a lateral internal threaded tube, a lateral adjustment drive lead screw and a lateral adjustment drive motor;

[0012] Adjustment plates are rotatably installed on the left and right side edges of the installation platform; a transverse adjustment support rod with an upper end hinged on an adjustment plate is fixed in the installation shell; the transverse adjustment drive tube is vertically fixed in the installation shell; the transverse internal threaded tube is vertically slidably installed on the transverse adjustment drive tube, and the upper end is laterally movably installed on another adjustment plate; the transverse adjustment drive screw is rotatably installed in the transverse adjustment drive tube, and is used to drive the transverse internal threaded tube to move vertically; the transverse adjustment drive motor drives the transverse internal threaded tube to rotate through a bevel gear pair, and is electrically connected to the PLC control unit through a transverse adjustment drive circuit.

[0013] Furthermore, the longitudinal adjustment unit includes a U-shaped seat and an electric telescopic rod; the U-shaped seat is fixed on two adjustment plates; the electric telescopic rod is installed on the U-shaped seat and is electrically connected to the PLC control unit through the telescopic rod drive circuit; the output end of the electric telescopic rod is longitudinally movably installed on the mounting platform.

[0014] Furthermore, the present invention also provides an observation method of a GNSS field observation system based on PLC, comprising the following steps:

[0015] Step 1: After the PLC-based GNSS field observation system is fixedly installed at the field observation point, the PLC-based GNSS field observation system is started;

[0016] Step 2: The PLC control unit controls the horizontal adjustment mechanism to operate so that the installation platform is in a horizontal state;

[0017] Step 3: The PLC control unit controls the north-seeking mechanism to operate so that the north-pointing mark of the GNSS antenna faces north;

[0018] Step 4: The PLC control unit controls the GNSS positioning module and the GNSS antenna to collect GNSS data and store them in the memory, and uploads the GNSS data to the remote control center regularly through the wireless communication module.

[0019] Compared with the prior art, the present invention has the following beneficial effects: GNSS data collection is realized by utilizing the GNSS positioning module and the GNSS antenna and stored in a memory, and the PLC control unit periodically uploads the data in the memory to a remote control center through a wireless communication module, thereby realizing unmanned data collection; a horizontal adjustment mechanism is utilized to adjust the installation platform under the control of the PLC control unit, so that the installation platform is in a horizontal state, thereby providing working conditions for the GNSS positioning module and the GNSS antenna; a north-seeking mechanism is utilized to drive the tube shaft to rotate, so that the north-pointing mark of the GNSS antenna faces north, thereby ensuring the accuracy of the collected GNSS data; a distance measuring sensor is utilized to detect the distance between the GNSS antenna and the inner bottom surface of the installation shell, and the data is uploaded to the remote control center, thereby ensuring the accuracy of the GNSS data. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a cross-sectional view of the present invention;

[0021] Figure 2 It is a front view of the present invention;

[0022] Figure 3 A bottom view of the mounting platform of the present invention;

[0023] Figure 4 is a cross-sectional view of the horizontal adjustment driving pipe of the present invention;

[0024] Figure 5 This is a schematic diagram of the installation of the control box of the present invention;

[0025] Figure 6 It is a schematic diagram of the circuit structure of the present invention;

[0026] In the figure: 1. Protective cover; 2. Control box; 3. Display screen; 4. Key panel; 5. Battery; 6. PLC control unit; 7. North-seeking gyroscope; 8. Bottom plate; 9. Positioning ring; 10. Locking bolt; 11. Support foot; 12. Support plate; 13. Handle; 14. GNSS antenna; 15. Flexible shielding bucket; 16. Pipe shaft; 17. Retaining ring; 18. Extension hole; 19. Rotary drive motor; 20. Rotary drive worm; 21. Rotary drive worm wheel; 22. Mounting platform; 23. Dual-axis tilt sensor; 24. Adjustment plate; 2 5. Horizontal adjustment support rod; 26. Adjustment shaft; 27. Horizontal movement seat; 28. Horizontal movement slot; 29. ​​Observation hole; 30. Horizontal movement block; 31. Horizontal movement internal threaded tube; 32. Lifting guide slot; 34. Horizontal adjustment drive screw; 35. Driven bevel gear; 36. Active bevel gear; 37. Horizontal adjustment drive tube; 38. Horizontal adjustment drive motor; 39. Avoidance slot; 40. Mounting plate; 41. Positioning tube; 42. Distance measuring sensor; 43. U-shaped seat; 44. Longitudinal movement seat; 45. Longitudinal movement slot; 46. Longitudinal movement block; 47. Electric telescopic rod. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0028] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In the description of the present invention, it should be understood that the terms "left", "right", "front", "back", "up", "down", "top", "bottom", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only simplified descriptions for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0030] Embodiment 1:

[0031] like Figure 1-6 As shown, a PLC-based GNSS field observation system provided by the present invention includes: a control box 2, a mounting shell, a mounting platform 22, a north-seeking mechanism and a horizontal adjustment mechanism;

[0032] The control box 2 is mounted on the mounting housing; a PLC control unit 6 and a battery 5 for power supply are mounted in the mounting housing; a wireless communication module and a memory electrically connected to the PLC control unit 6 are mounted in the control box 2; the PLC control unit 6 is electrically connected to the battery 5 via a voltage detection circuit;

[0033] A horizontal adjustment mechanism is installed in the installation shell; the installation platform 22 is installed on the horizontal adjustment mechanism, and the horizontal adjustment mechanism adjusts the horizontality of the installation platform 22; an observation hole 29 is arranged at the center of the installation platform 22; a positioning tube 41 connected to the observation hole 29 is fixed on the upper side of the installation platform 22; a pipe shaft 16 that passes through the top of the installation shell is coaxially rotatably installed on the upper end of the positioning tube 41; a GNSS antenna 14 that is electrically connected to the PLC control unit 6 through a GNSS positioning module is installed in the pipe shaft 16; a north-seeking mechanism is installed in the installation shell, and is used to drive the pipe shaft 16 to rotate so that the north pointer of the GNSS antenna 14 faces the north; a distance measuring sensor 42 that is electrically connected to the PLC control unit 6 is installed in the installation shell, and is used to detect the distance between the GNSS antenna 14 and the bottom surface of the installation shell; the north-seeking mechanism and the horizontal adjustment mechanism are both driven and controlled by the PLC control unit 6.

[0034] GNSS data collection is realized by using the GNSS positioning module and the GNSS antenna 14. The PLC control unit 6 stores the GNSS data in the memory. The PLC control unit 6 regularly uploads the data in the memory to the remote control center through the wireless communication module, so as to realize unmanned data collection and reduce the error introduced by manual operation. The installation platform 22 is adjusted by the horizontal adjustment mechanism under the control of the PLC control unit 6 so that the installation platform 22 is in a horizontal state, providing working conditions for the GNSS positioning module and the GNSS antenna 14. The north-seeking mechanism is used to drive the pipe shaft 16 to rotate so that the north mark of the GNSS antenna 14 is in the right position. For the north, the accuracy of the collected GNSS data is ensured; the distance between the GNSS antenna 14 and the inner bottom surface of the installation shell is detected by using the distance measuring sensor 42, and the data is uploaded to the remote control center, so that the remote control center can calculate the height of the GNSS antenna 14 based on the length of the GNSS antenna 14 and the distance between the inner bottom surface and the outer bottom surface of the installation shell to ensure the accuracy of the GNSS data; the cooperation between the north-seeking mechanism and the horizontal adjustment mechanism can improve the automation level of GNSS field observation; the voltage detection circuit is used to monitor the power of the battery 5, and when the power is lower than the threshold, a low power alarm is sent to the remote control center.

[0035] Furthermore, the mounting shell includes a protective cover 1 and a base plate 8; a positioning ring 9 with a vertical axis is fixed at the edge of the upper side of the base plate 8; the positioning ring 9 is used to be fitted into the lower opening of the protective cover 1 and is fixed to the protective cover 1 by a locking bolt 10; a plurality of legs 11 are fixed on the lower side of the base plate 8; a support plate 12 is provided on the lower side of each leg 11; an extension hole 18 for the pipe axis 16 to pass through is provided on the top of the protective cover 1; a handle 13 is installed on the top of the protective cover 1; a horizontal adjustment mechanism, a PLC control unit 6, a battery 5 and a distance sensor 42 are all installed on the base plate 8.

[0036] By utilizing the cooperation between the protective cover 1, the positioning ring 9 and the locking bolt, the installation housing can be opened to facilitate maintenance of the components in the installation housing; the support feet 11 are used to lift the base plate 8 off the ground to reduce the possibility of water entering the installation housing; the handle 13 is used to facilitate lifting and moving the observation system when not in use.

[0037] Furthermore, a retaining ring 17 is butted against the upper opening of the extension hole 18 ; and a flexible shielding bucket 15 for covering the retaining ring 17 is fixed to the bottom of the GNSS antenna 14 .

[0038] The flexible shielding bucket 15 is used to cover the upper opening of the blocking ring 17 to prevent rainwater from entering the installation housing and to play a certain dust-proof role.

[0039] Furthermore, a mounting plate 40 is provided on the positioning ring 9 ; the control box 2 is mounted on the mounting plate 40 ; and an avoidance notch 39 for avoiding the control box 2 is provided on the lower edge of the protective cover 1 .

[0040] The mounting plate 40 and the avoidance notch 39 are used to facilitate installation of the control box 2 , and when the protective cover 1 is disassembled and assembled, the relative position of the control box 2 and the PLC control unit 6 is ensured to remain unchanged, thereby preventing the cable from being pulled.

[0041] Furthermore, a key panel 4 and a display screen 3 electrically connected to a PLC control unit 6 are mounted on the control box 2. The display screen 3 is used to display the level of the installation platform 22, the power level of the battery 5, or the position of the north-finding mechanism, etc., under the control of the controller according to the needs.

[0042] Furthermore, the north-seeking mechanism includes a north-seeking gyroscope 7, a rotation drive motor 19 and a worm gear pair; the worm gear pair includes a rotation drive worm 20 and a rotation drive worm wheel 21; the rotation drive motor 19 is installed on the positioning tube 41, and is electrically connected to the PLC control unit 6 through the rotation drive circuit; the rotation drive worm 20 is docked on the output shaft of the rotation drive motor 19; the rotation drive worm wheel 21 is installed on the tube shaft 16, and is meshed with the rotation drive worm 20; the north-seeking gyroscope 7 is installed on the base plate 8, and is electrically connected to the PLC control unit 6.

[0043] The rotary drive motor 19 is used to drive the rotary drive worm 20 to rotate under the control of the PLC control unit 6, and the rotary drive worm wheel 21 drives the tube shaft 16 to rotate, thereby rotating the GNSS antenna 14; the north-seeking gyroscope 7 is used to help the PLC control unit 6 determine the direction, and the PLC control unit 6 controls the rotary drive motor 19 according to the signal provided by the north-seeking gyroscope, so that the north pointer of the GNSS antenna 14 faces the north.

[0044] Furthermore, the horizontal adjustment mechanism includes a transverse adjustment unit and a longitudinal adjustment unit; the transverse adjustment unit is installed on the base plate 8, and the mounting platform 22 is installed on the transverse adjustment unit, and the transverse adjustment unit adjusts the height difference between the left and right sides of the mounting platform 22; the longitudinal adjustment unit is installed on the transverse adjustment unit, and is used to adjust the height difference between the front and rear sides of the mounting platform 22; the transverse adjustment unit and the longitudinal adjustment unit are both driven and controlled by the PLC control unit 6; a dual-axis inclination sensor 23 electrically connected to the PLC control unit 6 is installed on the upper side of the mounting platform 22.

[0045] A dual-axis inclination sensor 23 is used to monitor the horizontality of the installation platform 22 and transmit the horizontality data to the PLC control unit 6. The PLC control unit 6 adjusts the installation platform 22 through the lateral adjustment unit and the longitudinal adjustment unit. The lateral adjustment unit drives the installation platform 22 to swing left and right, and the longitudinal adjustment unit drives the installation platform 22 to swing back and forth until the installation platform 22 is in a horizontal state, thereby achieving leveling and ensuring the accuracy of GNSS data collection.

[0046] Furthermore, the horizontal adjustment unit includes a horizontal adjustment drive tube 37, a horizontal internal threaded tube 31, a horizontal adjustment drive screw 34, a horizontal adjustment drive motor 38 and a bevel gear pair; the bevel gear pair includes a driving bevel gear 36 and a driven bevel gear 35;

[0047] An adjustment plate 24 is rotatably mounted on both the left and right edges of the mounting platform 22 through an adjustment shaft 26; a transverse adjustment support rod 25 is fixed on the bottom plate 8, and the upper end of the transverse adjustment support rod 25 is hinged on the left adjustment plate 24; a transverse movable seat 27 is fixed on the right adjustment plate 24; a transverse movable groove 28 is horizontally arranged on the lower side of the transverse movable seat 27; a transverse block 30 is horizontally slidably mounted on the transverse movable groove 28; the lower end of the transverse adjustment drive pipe 37 is fixed on the bottom plate 8; the lower end of the transverse internal threaded pipe 31 is vertically slidably mounted on the upper end of the transverse adjustment drive pipe 37, and the upper end is hinged on the transverse block 3 0; a lifting guide groove 32 is vertically arranged on the circumferential side wall of the transverse internal threaded tube 31; a lifting guide slider slidably matched with the lifting guide groove 32 is arranged on the upper side of the inner wall of the transverse adjustment drive tube 37; the transverse adjustment drive screw 34 is rotationally coaxially installed in the transverse adjustment drive tube 37, and the thread is screwed on the transverse internal threaded tube 31; the driven bevel gear 35 is installed on the transverse adjustment drive screw 34; the transverse adjustment drive motor 38 is installed on the base plate 8, and is electrically connected to the PLC control unit 6 through the transverse adjustment drive circuit; the active bevel gear 36 is installed on the output shaft of the transverse adjustment drive motor 38, and is meshed with the driven bevel gear 35.

[0048] The lateral adjustment driving motor 38 drives the active bevel gear 36 to rotate under the control of the PLC control unit 6, and the driven bevel gear 35 drives the lateral adjustment driving screw 34 to rotate, so that the lateral internal threaded tube 31 is lifted and lowered, and the lateral block 30 slides in the lateral movable groove 28 following the lateral internal threaded tube 31, and under the hinged installation condition of the lateral adjustment support rod 25, the two adjustment plates 24 drive the installation platform 22 to swing left and right; the cooperation between the lifting guide groove 32 and the lifting guide slider is utilized to ensure the vertical movement of the lateral internal threaded tube 31 on the lateral adjustment driving tube 37, and prevent the lateral adjustment driving tube 37 from rotating following the lateral adjustment driving screw 34.

[0049] Furthermore, the longitudinal adjustment unit includes a U-shaped seat 43 and an electric telescopic rod 47; a longitudinal movable seat 44 is longitudinally installed on the rear side of the mounting platform 22; a longitudinal movable groove 45 is longitudinally arranged on the lower side of the longitudinal movable seat 44; a longitudinal block 46 is longitudinally slidably installed on the longitudinal movable groove 45; the two ends of the U-shaped seat 43 are respectively fixed on the two adjustment plates 24; the electric telescopic rod 47 is installed on the U-shaped seat 43, and is electrically connected to the PLC control unit 6 through the telescopic rod drive circuit, and the output end of the electric telescopic rod 47 is hinged on the longitudinal block 46.

[0050] By utilizing the rotational connection between the mounting platform 22 and the two adjustment plates 24, the mounting platform 22 can swing back and forth, the electric telescopic rod 47 is extended and retracted under the control of the PLC control unit 6, and the longitudinal movement block 46 follows the end of the electric telescopic rod 47 to slide longitudinally in the longitudinal movement active groove 45, thereby realizing the adjustment of the mounting platform 22.

[0051] Furthermore, the present invention also provides an observation method of a GNSS field observation system based on PLC, comprising the following steps:

[0052] Step 1: After the PLC-based GNSS field observation system is fixedly installed at the field observation point, the PLC-based GNSS field observation system is started; the start button on the key panel 4 is pressed to enable the battery 5 to supply power, and each component is powered;

[0053] Step 2: The PLC control unit 6 controls the horizontal adjustment mechanism to operate so that the installation platform 22 is in a horizontal state;

[0054] The dual-axis inclination sensor 23 monitors the horizontality data of the installation platform 22, and the PLC control unit 6 controls the extension and retraction of the electric telescopic rod 47 and the operation of the horizontal adjustment drive motor 38 according to the horizontality data; the horizontal adjustment drive motor 38 drives the driven bevel gear 35 to rotate through the active bevel gear 36, and the horizontal adjustment drive screw 34 drives the horizontal internal threaded tube 31 to rise and fall until the installation platform 22 is in a horizontal state;

[0055] Step 3: The PLC control unit 6 controls the north-finding mechanism to operate so that the north-pointing mark of the GNSS antenna 14 faces north;

[0056] The north-seeking gyroscope 7 is used to help the PLC control unit 6 determine the direction. The PLC control unit 6 controls the rotation drive motor 19 to operate according to the signal provided by the north-seeking gyroscope, and the rotation drive worm 20 drives the rotation drive worm wheel 21 to rotate, and the tube shaft 16 drives the GNSS antenna 14 to rotate, so that the north-pointing mark of the GNSS antenna 14 faces the north.

[0057] Step 4: The PLC control unit 6 controls the GNSS positioning module and the GNSS antenna 14 to collect GNSS data, and uploads the GNSS data to the remote control center in real time through the wireless communication module.

[0058] In the PLC-based GNSS field observation system provided by the present invention, the PLC control unit 6 adopts the existing PLC control module; the wireless communication module adopts the existing wireless communication module; the memory adopts the existing memory; the display screen 3 adopts the existing display screen; the distance sensor 42 adopts the existing infrared distance sensor; the dual-axis tilt sensor 23 adopts the existing dual-axis tilt sensor; the battery 5 adopts the existing battery; the voltage detection circuit adopts the existing voltage detection circuit module; the north-seeking gyroscope 7 adopts the existing gyro north-seeking instrument; the rotation drive motor 19 and the lateral adjustment drive motor 38 both adopt the existing stepping motor, and the rotation drive circuit and the lateral adjustment drive circuit adopt the corresponding stepping motor drive circuit; the electric telescopic rod 47 adopts the existing electric telescopic rod, and the telescopic rod drive circuit adopts the corresponding electric telescopic rod drive circuit; the GNSS antenna 14 adopts the existing GNSS antenna, and the GNSS positioning module adopts the existing GNSS positioning module.

[0059] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A PLC-based GNSS field observation system, characterized by: The invention comprises a control box (2), a mounting shell, a mounting platform (22), a north-seeking mechanism and a horizontal adjustment mechanism; a PLC control unit (6) and a storage battery (5) for power supply are installed in the mounting shell; a wireless communication module and a memory electrically connected to the PLC control unit (6) are installed in the control box (2); the horizontal adjustment mechanism is installed in the mounting shell; the mounting platform (22) is installed on the horizontal adjustment mechanism, and the horizontality of the mounting platform (22) is adjusted by the horizontal adjustment mechanism; an observation hole (29) is provided on the mounting platform (22); a positioning tube (41) is connected to the observation hole (29); and a positioning tube (41) is connected to the positioning tube (41). ) is rotatably mounted on a tube shaft (16) that passes through the top of the mounting shell; a GNSS antenna (14) that is electrically connected to the PLC control unit (6) through a GNSS positioning module is mounted on the top of the tube shaft (16); a north-finding mechanism is mounted in the mounting shell and is used to drive the tube shaft (16) to rotate so that the north-pointing mark of the GNSS antenna (14) faces north; a distance-measuring sensor (42) that is electrically connected to the PLC control unit (6) is mounted in the mounting shell and is used to detect the distance between the GNSS antenna (14) and the bottom surface of the mounting shell; the north-finding mechanism and the horizontal adjustment mechanism are both driven and controlled by the PLC control unit (6).

2. The PLC-based GNSS field observation system according to claim 1, characterized in that: The mounting shell comprises a protective cover (1) and a bottom plate (8); a positioning ring (9) mounted at an opening on the lower side of the protective cover (1) is fixed on the bottom plate (8); a protruding hole (18) for a pipe shaft (16) to pass through is provided on the top of the protective cover (1); and a handle (13) is installed on the top of the protective cover (1).

3. The PLC-based GNSS field observation system according to claim 2, characterized in that: A retaining ring (17) is butted against the upper opening of the extension hole (18); and a flexible shielding bucket (15) for covering the retaining ring (17) is arranged on the bottom of the GNSS antenna (14).

4. The PLC-based GNSS field observation system according to claim 2, characterized in that: A mounting plate (40) is arranged on the positioning ring (9); the control box (2) is mounted on the mounting plate (40); and an avoidance notch (39) for avoiding the control box (2) is arranged on the lower edge of the protective cover (1).

5. The PLC-based GNSS field observation system according to claim 1, characterized in that: A key panel (4) and a display screen (3) electrically connected to a PLC control unit (6) are mounted on the control box (2).

6. The PLC-based GNSS field observation system according to claim 1, characterized in that: The north-seeking mechanism comprises a north-seeking gyroscope (7) and a rotation drive motor (19); the rotation drive motor (19) is mounted on a positioning tube (41), drives a tube shaft (16) to rotate via a worm gear transmission pair, and is electrically connected to a PLC control unit (6) via a rotation drive circuit; the north-seeking gyroscope (7) is mounted on the inner bottom surface of a mounting shell, and is electrically connected to the PLC control unit (6).

7. The PLC-based GNSS field observation system according to claim 1, characterized in that: The horizontal adjustment mechanism comprises a horizontal adjustment unit and a vertical adjustment unit; the horizontal adjustment unit is installed in a mounting shell, the mounting platform (22) is installed on the horizontal adjustment unit, and the horizontal adjustment unit adjusts the height difference between the left and right sides of the mounting platform (22); the vertical adjustment unit is installed on the horizontal adjustment unit and is used to adjust the height difference between the front and rear sides of the mounting platform (22); the horizontal adjustment unit and the vertical adjustment unit are both driven and controlled by a PLC control unit (6); a dual-axis inclination sensor (23) electrically connected to the PLC control unit (6) is installed on the upper side of the mounting platform (22).

8. The PLC-based GNSS field observation system according to claim 7, characterized in that: The horizontal adjustment unit comprises a horizontal adjustment drive tube (37), a horizontal displacement internal thread tube (31), a horizontal adjustment drive screw rod (34) and a horizontal adjustment drive motor (38); An adjustment plate (24) is rotatably mounted on both left and right side edges of the mounting platform (22); a horizontal adjustment support rod (25) whose upper end is hinged on an adjustment plate (24) is fixed in the mounting shell; a horizontal adjustment drive tube (37) is vertically fixed in the mounting shell; a horizontal displacement internal threaded tube (31) is vertically slidably mounted on the horizontal displacement drive tube (37), and its upper end is laterally movably mounted on another adjustment plate (24); a horizontal displacement drive screw rod (34) is rotatably mounted in the horizontal displacement drive tube (37) for driving the horizontal displacement internal threaded tube (31) to move vertically; a horizontal displacement drive motor (38) drives the horizontal displacement internal threaded tube (31) to rotate via a bevel gear pair, and is electrically connected to a PLC control unit (6) via a horizontal displacement drive circuit.

9. The PLC-based GNSS field observation system according to claim 8, characterized in that: The longitudinal adjustment unit comprises a U-shaped seat (43) and an electric telescopic rod (47); the U-shaped seat (43) is fixed on two adjustment plates (24); the electric telescopic rod (47) is installed on the U-shaped seat (43) and is electrically connected to a PLC control unit (6) via a telescopic rod driving circuit; and the output end of the electric telescopic rod (47) is longitudinally movably installed on a mounting platform (22).

10. The observation method of the PLC-based GNSS field observation system according to claim 1, characterized in that: The steps include: Step 1: After the PLC-based GNSS field observation system is fixedly installed at the field observation point, the PLC-based GNSS field observation system is started; Step 2: The PLC control unit (6) controls the horizontal adjustment mechanism to operate so that the installation platform (22) is in a horizontal state; Step 3: The PLC control unit (6) controls the north-finding mechanism to operate so that the north-pointing mark of the GNSS antenna (14) faces north; Step 4: The PLC control unit (6) controls the GNSS positioning module and the GNSS antenna (14) to collect GNSS data and store them in a memory, and uploads the GNSS data to the remote control center regularly through the wireless communication module.

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