Method for monitoring dike deformation through laser dotting of unmanned aerial vehicle

Abstract

The invention discloses a method for monitoring embankment deformation through unmanned aerial vehicle laser dotting, and the method comprises the following steps: 1, determining the number and positions of embankment deformation key monitoring points, and applying a deformation monitoring target which acts on the recognition of an unmanned aerial vehicle to each embankment deformation key monitoring point; secondly, measuring points in one-to-one correspondence with the dike deformation key monitoring points are determined; thirdly, planning a patrol route; 4, patrolling; 5, data analysis is carried out; measurement personnel can obtain a conclusion about whether deformation occurs or not and the deformation degree according to the position of the bright laser point on the deformation monitoring target in the photo image. The method has high monitoring efficiency and monitoring precision, reduces the monitoring cost and the technical complexity, has good popularization and application values, has important significance for maintaining the embankment function and ensuring the embankment safety, and is expected to become a mainstream technology for embankment deformation monitoring in the future.

Description

Technical Field

[0001] The present invention relates to the technical field of water conservancy projects, and particularly to the technology of levee deformation monitoring. Background Art

[0002] A levee is a water retaining structure built along the banks of rivers, lakes, etc., or at the edges of flood diversion areas and reclamation areas. The main structure of the levee is the embankment body, and the foundation of the embankment body is the levee foundation, which is in direct contact with the soil. There are slope protection structures (belonging to accessories) on both sides of the embankment body to protect the embankment body from scouring by water flow and invasion by wind and waves. There is a seepage prevention structure inside the embankment body. The levee has structures that pass through the levee (such as power, telecommunications pipelines, water conveyance pipelines, drainage pipelines, culverts, etc.) and structures that do not pass through the levee (such as management building facilities, protection facilities, some drainage structures, etc.); in the present invention, the structures that pass through the levee are uniformly referred to as levee-piercing objects, and the structures that do not pass through the levee are called accessories. There are deformation joints or expansion joints on the embankment body or accessories (such as between the slope protection sections of segmented slope protection); the embankment body and the levee foundation are uniformly referred to as the levee body.

[0003] The levee is exposed to the natural environment for a long time and is affected by factors such as water flow scouring, soil settlement, and weathering. It may undergo deformation during long-term use. The deformation of the levee may bring the following hazards: 1. Risk of levee breach; 2. Increased seepage; 3. Landslide or collapse phenomenon; 4. Appearance of fracture points on the levee; 5. Drainage failure; 6. Failure of the functions of the levee top (mainly traffic and inspection); 7. Economic losses and environmental damage.

[0004] To avoid the above hazards, it is necessary to monitor the deformation of the levee, so as to timely discover problems and carry out corresponding maintenance work, thereby ensuring the safety of the levee project, extending the service life of the levee, and avoiding huge losses caused by the above phenomena. At the same time, the monitoring data helps to understand the working state of the dam, provides feedback for engineering design and construction, improves methods, and enhances the quality and safety of future construction. In addition, the levee deformation monitoring can also provide a scientific basis for emergency management, help formulate effective response strategies, and reduce losses caused by disasters.

[0005] Introduction to existing levee deformation monitoring technologies: 1. GNSS monitoring.

[0006] Using the global navigation satellite system for high-precision real-time monitoring, the advantages are high precision and real-time monitoring, but the disadvantages are also obvious. It is necessary to deploy multiple reference stations in the monitoring area, resulting in high costs; it is highly dependent on the environment, and factors such as weather, trees, and buildings will affect the signal reception accuracy.

[0007] 2. InSAR technology. Through synthetic aperture radar interferometry, its advantages are large coverage and strong long-term monitoring ability. Its disadvantages are low accuracy, inability to monitor in real time, and sensitivity to vegetation and water bodies. Vegetation coverage and water body reflection can both cause monitoring errors.

[0008] 3. Total station monitoring. The cost is medium. Its advantages are high accuracy, simple to use, and suitable for short-term monitoring tasks. Its disadvantages are low monitoring efficiency and being greatly affected by weather.

[0009] 4. Fiber optic sensor technology. Its advantages are high sensitivity, suitable for fine monitoring, and suitable for continuous monitoring of long linear areas of levees. Its disadvantages are high installation cost, easy to be damaged during long-term use, not suitable for large-scale installation, and thus not suitable for large-area monitoring.

[0010] 5. UAV monitoring. Using the camera or LiDAR system of the UAV to conduct a comprehensive 3D modeling of the levee, establishing the original 3D model and the current 3D model of the levee, and monitoring the deformation of the levee by comparing the current 3D model with the original 3D model. Its advantages are strong flexibility, able to quickly cover levee areas that are difficult to reach by other monitoring methods, high monitoring resolution, and better visualization effect and analysis ability for large-scale or continuous deformations. Its disadvantages are that it requires a comprehensive 3D modeling of the levee, large workload, long flight time, high overall cost, and low monitoring efficiency.

[0011] The present invention is the development of UAV monitoring technology. Summary of the Invention

[0012] The purpose of the present invention is to provide a method for monitoring the deformation of a levee by UAV laser dotting, using a point-to-point distance monitoring method to replace the existing levee deformation monitoring method, reducing costs and improving efficiency.

[0013] To achieve the above purpose, the present invention provides a method for monitoring the deformation of a levee by UAV laser dotting. The levee includes a levee body provided on a levee foundation. The UAV is equipped with a flight controller, a camera installed on a camera gimbal, a laser emitter, and a GNSS module and / or RTK module for determining the three-dimensional positioning information of the UAV; The levee body and the levee foundation are collectively referred to as the levee main body; the structures at the levee main body are divided into levee-crossing structures and accessory structures according to whether they cross the levee. The structures that cross the levee are levee-crossing structures, and the structures that do not cross the levee are accessory structures. There are slope protection structures on both sides of the levee body, and the slope protection structures belong to accessory structures; there is a levee top at the top of the levee body, and the levee top is a part of the levee body; The present invention is carried out in the following steps in sequence: The first step is that the surveyor determines the number and positions of the key deformation monitoring points of the levee according to the specific situation of the levee structure, and applies deformation monitoring targets that can be recognized by the UAV at each key deformation monitoring point of the levee; The deformation monitoring target has an annular structure, including a solid circular center and three concentric rings with different diameters. The radius of the solid circular center is r1, the width of the ring of the ring is r2, and the distances from the three concentric rings to the solid circular center from the inside to the outside are d1, d2, and d3 respectively; The concentric ring with the relatively smallest diameter is called the first ring, the concentric ring with the relatively largest diameter is called the third ring, and the concentric ring with the medium diameter is called the second ring; The second step is to determine the measurement points corresponding one by one to the key deformation monitoring points of each dike; when determining the measurement points, the operator manipulates the unmanned aerial vehicle (UAV) equipped with a fixed-angle laser emitter to emit laser at each deformation monitoring target on the dike one by one; For a specific deformation monitoring target, a bright laser spot is formed on the irradiated surface of the deformation monitoring target by the laser; adjust the spatial position of the UAV so that the laser spot coincides with the center of the deformation monitoring target; adjust the camera gimbal angle of the UAV so that the deformation monitoring target is completely photographed by the camera of the UAV; record the three-dimensional spatial position and the camera gimbal angle of the UAV at this time, and store them as the waypoint information of the UAV. This three-dimensional spatial position is called the measurement point; the second step obtains the measurement points corresponding to all monitoring points; The third step is to plan the inspection flight route; the survey personnel smoothly connect all the UAV measurement points in series as the navigation passing points of the UAV flight route to obtain the inspection flight route for the UAV to inspect the dike; store the inspection flight route in the UAV; the inspection flight route has a starting point and an ending point, and the three-dimensional positioning information of the starting point and the ending point is stored in the flight controller; The fourth step is inspection; The survey personnel determine the inspection frequency according to needs; during daily inspections, the UAV arrives at each measurement point one by one along the inspection flight route; when arriving at any measurement point, the UAV hovers, adjusts the body orientation and the camera gimbal angle according to the waypoint information corresponding to this measurement point, emits laser at the same spatial angle, and the three-dimensional spatial position of this laser coincides with the laser emitted by the UAV when determining the measurement point in the second step, and a bright laser spot is formed on the irradiated surface. At this time, the camera carried by the UAV takes a picture of the deformation monitoring target, and after the shooting is completed, it flies to the next measurement point; after completing the shooting tasks of all measurement points, the UAV returns; The fifth step is data analysis; The survey personnel export the images of the deformation monitoring targets taken by the UAV for viewing; If the bright laser spot in the photo coincides with the center of the deformation monitoring target, it indicates that no deformation has occurred at the corresponding key deformation monitoring point of the dike; If the bright laser spot in the photo does not coincide with the center of the deformation monitoring target, it indicates that deformation has occurred at the corresponding key deformation monitoring point of the dike.

[0014] In the fifth step, when deformation occurs at the key monitoring points of the dike, the surveyors classify the degree of deformation into slight deformation, moderate deformation, and severe deformation according to the following principles: When the bright laser spot in the photo is between the bull's-eye and the first ring of the deformation monitoring target or on the first ring, the degree of deformation of the corresponding key monitoring point of the dike deformation is classified as slight deformation; When the bright laser spot in the photo is between the first ring and the second ring of the deformation monitoring target or on the second ring, the degree of deformation of the corresponding key monitoring point of the dike deformation is classified as moderate deformation; When the bright laser spot in the photo is between the second ring and the third ring of the deformation monitoring target or on the third ring, the degree of deformation of the corresponding key monitoring point of the dike deformation is classified as severe deformation.

[0015] Specifically, the first step is that the surveyors respectively select several key monitoring points of dike deformation at the following monitoring positions: ① The joint between the structure passing through the dike and the dike body not covered by the accessory; ② The joint between the structure passing through the dike and the accessory covering the dike body; ③ The joint between the accessory and the dike body; ④ The joint between accessories; ⑤ The deformation joint of the dike body or the slope protection structure; ⑥ The dike crest; ⑦ The middle section of the dike body; ⑧ The places where structural problems have occurred historically or the known geologically weak areas; ⑨ The connection between the dike body and the bank.

[0016] The present invention has the following advantages: The present invention has the following advantages: Low cost. Using the unmanned aerial vehicle to move to complete the monitoring work of all key monitoring points of dike deformation, there is no need to set up multiple monitoring stations; and only key points need to be monitored, not comprehensive monitoring; only photography is required, not three-dimensional scanning and modeling, and there is no need for comprehensive comparison between three-dimensional models, saving workload and computing volume. In terms of hardware, there is no need to build observation stations or radar stations, and the cost is greatly reduced compared with building stations, and the cost is also greatly reduced compared with burying optical fiber sensors along the whole dike.

[0017] Strong flexibility and easy to use. The unmanned aerial vehicle can conveniently and quickly cover the dike areas that are difficult to monitor by other monitoring methods. The monitoring frequency can be adjusted according to the situation, and inspection work can also be carried out at any time when needed.

[0018] The accuracy is relatively high. By using GNSS and RTK technologies, the positioning accuracy of the UAV itself can reach the centimeter level, and the accuracy of laser measurement itself can reach the micron level, with very accurate ranging. For levee deformation, accuracies at the millimeter level and below are not necessary, and centimeter-level accuracy is sufficient for levee warning purposes.

[0019] Basically, there is no need to design new algorithms. The data analysis step can be confirmed by the surveyors observing the photo images to determine whether deformation has occurred and the degree of deformation.

[0020] Generally speaking, the present invention has high monitoring efficiency and monitoring accuracy, reduces the monitoring cost and technical complexity, has good popularization and application value, and is of great significance for maintaining the levee function and ensuring the levee safety.

[0021] The key monitoring points of levee deformation cover the relatively unstable parts of the levee structure, so it can well replace the levee deformation monitoring technology of three-dimensional modeling and comparing three-dimensional models. Although the levee top is not a relatively unstable part of the structure, its height is very representative of levee deformation, so key monitoring points of levee deformation are also set on the levee top.

[0022] The R & D motivation of the present invention is: taking advantage of the high flexibility characteristics of UAV monitoring to reduce the cost of UAV monitoring, including the hardware cost brought by comprehensive three-dimensional modeling, and the time cost required for flight and modeling.

[0023] The technical idea of the present invention is: cancel comprehensive three-dimensional modeling and replace it with distance monitoring of key monitoring points of levee deformation.

[0024] By carrying a GNSS module and / or an RTK module, the UAV platform can accurately position its own spatial position, enabling the UAV to be converted from a mobile platform to a platform with a fixed position.

[0025] The present invention proposes the concept of key monitoring points of levee deformation. Through research, for the levee deformation problem, there are some key points on the levee-related structures. If there is no obvious deformation at these key points, then there will be no major deformation risks for the levee-related structures, and problems such as levee breach, increased leakage, landslide or collapse can be avoided. If there is significant deformation at these key points, then greater deformation may occur subsequently, and various problems such as levee breach, increased leakage, landslide or collapse, levee fracture, drainage failure, and dam top failure may also follow. Therefore, the present invention proposes a technical idea that does not require comprehensive monitoring of the dam three-dimensional model, but only needs to monitor the key points of deformation.

[0026] The dike facility is an integral structure, and its various parts are interconnected and interact with each other. When a deformation occurs in a certain part of the dike facility, it will cause effects such as stress concentration or deformation transfer to adjacent parts, thereby leading to the instability of the entire structure. The key monitoring points for dike deformation are mainly the relatively more unstable parts of the dike-related structures, mainly the key points where the structure is stressed. The present invention makes a creative summary of this. The dike-related structures are divided into three categories: the dike body, the structures passing through the dike, and the appendages. The joints between any two of these three types of structures (specifically including the joints between the structures passing through the dike and the dike body or appendages, the joints between the appendages and the dike body, and the joints between the appendages) are the most unstable parts of the dike-related structures. If there are deformation joints (not necessarily) in the dike body or the slope protection structure, the deformation joints are also the key monitoring points for dike deformation. By selecting key monitoring points for dike deformation at the above positions for monitoring, the deformation of the dike-related structures can be effectively monitored and disasters can be prevented.

[0027] The present invention enriches the understanding of those skilled in the art. ① It first proposes the concept of the key monitoring points for dike deformation and uses it to monitor dike deformation. ② It first proposes the technical idea of using the shooting monitoring of the key monitoring points for dike deformation to replace the monitoring of the overall dike deformation. ③ In the prior art, the unmanned aerial vehicle is a mobile platform. The present invention first uses the unmanned aerial vehicle as a platform with a fixed position in the monitoring technology (measuring the distance between the fixed measuring point position and the key monitoring points for dike deformation). Each of the above contents has obvious originality. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of the deformation monitoring target.

[0029] Figure 2 It is a schematic diagram of the principle of monitoring dike deformation by laser dotting. Detailed Embodiments

[0030] As Figure 1 and Figure 2 shown, the present invention provides a method for monitoring dike deformation by laser dotting with an unmanned aerial vehicle. The dike includes a dike body provided on a dike foundation. The unmanned aerial vehicle is equipped with a flight controller, a camera installed on a camera gimbal, a laser emitter, and a GNSS module and / or an RTK module for determining the three-dimensional positioning information of the unmanned aerial vehicle. These two modules can control the spatial positioning error of the unmanned aerial vehicle within the centimeter level, with relatively high accuracy.

[0031] The embankment body and the embankment foundation are collectively referred to as the embankment main body; the structures at the embankment main body are divided into embankment-piercing structures (such as structures like power pipelines, telecommunication pipelines, water conveyance pipelines, drainage pipelines, and culverts) and accessory structures according to whether they pass through the embankment. The structures passing through the embankment are embankment-piercing structures, and the structures not passing through the embankment are accessory structures. Slope protection structures are provided on both sides of the embankment body, and the slope protection structures belong to accessory structures; a dike crest is provided at the top of the embankment body, and the dike crest is a part of the embankment body. The present invention is carried out in the following steps in sequence: The first step is that the surveyors determine the number and positions of the key deformation monitoring points of the embankment according to the specific situation of the embankment structure, and apply deformation monitoring targets recognized by the unmanned aerial vehicle (UAV) at each key deformation monitoring point of the embankment. The deformation monitoring target is similar to the target surface of target shooting, and is a circular structure, including a solid circle center and three concentric circles with different diameters. The radius of the solid circle center is r1, the ring width of the ring is r2, and the distances from the three concentric circles to the solid circle center from the inside to the outside are d1, d2, and d3 respectively. The values of r1, r2, d1, d2, and d3 are determined by the designers according to the specific situation of the embankment and the UAV; for example, d1 = 3 cm, d2 = 6 cm, d3 = 9 cm; the structure of the deformation monitoring target is as Figure 1 shown; The concentric circle with the relatively smallest diameter is called the first ring, the concentric circle with the relatively largest diameter is called the third ring, and the concentric circle with the medium diameter is called the second ring. The second step is to determine the measurement points corresponding to each key deformation monitoring point of the embankment; when determining the measurement points, the operator manipulates the UAV equipped with a fixed-angle laser emitter to emit laser at each deformation monitoring target on the embankment one by one. For a specific deformation monitoring target, a bright laser spot is formed on the irradiated surface of the deformation monitoring target by the laser; adjust the spatial position of the UAV so that the laser spot coincides with the center of the deformation monitoring target; adjust the camera gimbal angle of the UAV so that the deformation monitoring target is completely photographed by the camera of the UAV; record the three-dimensional spatial position (from the GNSS module and / or RTK module) and the camera gimbal angle of the UAV at this time, and store them as the waypoint information of the UAV. This three-dimensional spatial position is called the measurement point; the second step obtains the measurement points corresponding to all monitoring points. The third step is to plan the inspection flight route; the surveyors smoothly connect all the UAV measurement points as the navigation passing points of the UAV flight route to obtain the inspection flight route for the UAV to inspect the embankment; store the inspection flight route in the UAV; the inspection flight route has a starting point and an ending point, and the three-dimensional positioning information of the starting point and the ending point is stored in the flight controller. The fourth step is inspection; The surveyor determines the inspection frequency according to needs; during daily inspections, the drone reaches each measurement point one by one along the inspection flight route; when reaching any measurement point, the drone hovers, adjusts the body orientation and the camera gimbal angle according to the waypoint information corresponding to the measurement point, emits laser light at the same spatial angle, and the three-dimensional spatial position of this laser light coincides with the laser light emitted by the drone when determining the measurement point in the second step, and a bright laser spot is formed on the irradiated surface. At this time, the camera carried by the drone takes a picture of the deformation monitoring target. After the shooting is completed, it flies to the next measurement point; after completing the shooting tasks of all measurement points, the drone returns. The fifth step is data analysis. The surveyor exports the images of the deformation monitoring target taken by the drone for viewing. If the bright laser spot in the photo coincides with the center of the deformation monitoring target, it indicates that no deformation has occurred at the corresponding key dike deformation monitoring point. If the bright laser spot in the photo does not coincide with the center of the deformation monitoring target, it indicates that deformation has occurred at the corresponding key dike deformation monitoring point.

[0032] In the fifth step, when deformation has occurred at the key dike deformation monitoring point, the surveyor divides the degree of deformation into slight deformation, moderate deformation, and severe deformation according to the following principles: When the bright laser spot in the photo is between the center of the deformation monitoring target and the first ring or on the first ring, the degree of deformation of the corresponding key dike deformation monitoring point is divided into slight deformation. When the bright laser spot in the photo is between the first ring and the second ring of the deformation monitoring target or on the second ring, the degree of deformation of the corresponding key dike deformation monitoring point is divided into moderate deformation. When the bright laser spot in the photo is between the second ring and the third ring of the deformation monitoring target or on the third ring, the degree of deformation of the corresponding key dike deformation monitoring point is divided into severe deformation.

[0033] The specific values of the deformation monitoring target need to be set in combination with the allowable value of the dike deformation design. If the deformation amount is less than 20% of the allowable value of the design, it can be considered that no deformation has occurred, and at this time the laser spot coincides with the center of the deformation monitoring target; if the deformation amount is between 20% and 50% of the allowable value of the design, it belongs to slight deformation, and at this time the laser spot falls between the center of the target and the first ring, and regular monitoring needs to be maintained to ensure the safety of the dike; if the deformation amount is between 50% and 80% of the allowable value of the design, it belongs to moderate deformation, and at this time the laser spot falls between the first ring and the second ring, and the monitoring frequency needs to be increased to closely monitor the change trend; if the deformation amount reaches or exceeds 80% of the allowable value of the design, it belongs to severe deformation, and at this time the laser spot falls between the second ring and the third ring, and emergency measures need to be taken immediately, and detailed inspections and evaluations need to be carried out. When designing the deformation monitoring target, the designer determines the specific dimensions of the deformation monitoring target (including the diameter of the center of the target, the diameters and widths of the three concentric rings) according to the above principles.

[0034] The first step is specifically as follows: The surveyors respectively select a number of key monitoring points for dike deformation at the following monitoring locations: ① The joint between the structure passing through the dike and the dike body not covered by the accessory; ② The joint between the structure passing through the dike and the accessory covering the dike body; ③ The joint between the accessory and the dike body; ④ The joint between accessories; ⑤ The deformation joint of the dike body or the slope protection structure; ⑥ The dike top; Monitoring the settlement of the dike top is very important for understanding the overall stability of the dike.

[0035] ⑦ The middle section of the dike body; Settlement or displacement may occur in the middle section due to insufficient support; ⑧ The places where structural problems have occurred historically or the known geologically weak areas; These are the known areas prone to problems; ⑨ The connection between the dike body and the bank; Collapse or landslide may occur in these areas due to the scouring action of the water flow; A number of key monitoring points for dike deformation are evenly distributed at each monitoring location, and the distance between adjacent key monitoring points for dike deformation at each location is less than or equal to 10 meters.

[0036] Analysis of the application cost of the present invention: The inspection of dikes can be divided into regular inspections, periodic inspections, special inspections and irregular inspections.

[0037] Regular inspections: mainly refer to visual inspections. The management personnel should inspect the dike sections under their management once every 1 - 3 days; The grass-roots management organizations (shifts, groups, stations, sections) of dike projects should inspect once every about 10 days; The management units of dike projects should organize inspections once every 1 - 2 months. The specific inspection frequency should be determined according to factors such as the importance of the dike, its location and its operating status, and the inspection frequency should be increased according to the flood situation during the flood season.

[0038] Periodic inspections: Periodic inspections can be divided into pre-flood inspections, post-flood inspections and inspections before and after spring tides, tropical storms and typhoons, etc. One inspection should be carried out before and after floods, after floods and before and after spring tides, tropical storms and typhoons, and the inspection frequency should be increased in case of special circumstances.

[0039] Special inspections: When major floods, heavy rains, typhoons, felt earthquakes occur, as well as during extraordinary operation conditions of projects such as river closure and river opening and when major accidents occur, inspections should be carried out in a timely manner, and continuous monitoring should be carried out on the parts where danger may occur.

[0040] Irregular inspections: The dike body, dike foundation and toe protection of dangerous dike works, dangerous sections and important sections should be detected and inspected irregularly.

[0041] According to the current levee inspection process, the monitoring of levee deformation requires expensive equipment investment, labor expenditure and training costs, resulting in the monitoring of levee deformation becoming a complex process with high costs and long cycles. However, the method of using an unmanned aerial vehicle (UAV) with a laser dotting system to monitor levee deformation proposed in the present invention can well reduce the costs of this activity.

[0042] 1. In terms of equipment costs, the present invention has significant advantages. It mainly relies on relatively low-cost light UAVs and laser emitters for operation, without relying on third-party equipment such as expensive laser rangefinders, radar rangefinders or synthetic aperture radars. This simplified equipment requirement greatly reduces the investment cost of the entire monitoring system. In addition, the present invention determines the degree of levee deformation by comparing the positions of laser dots on the deformation monitoring target in the captured pictures, without the need to construct a complex three-dimensional model of the levee, thereby further saving the cost of high-performance computing equipment.

[0043] 2. In terms of labor costs, the present invention also shows high efficiency. Through intelligent UAVs for large-scale and long-distance levee inspections, the staff only needs to plan the flight path of the UAV in advance. When the inspection task is issued, this flight path can be quickly imported into the UAV system, and multiple UAVs can automatically execute the inspection task simultaneously and transmit the captured photos back to the local area in real time for unified deformation analysis. This automated and intelligent operation mode significantly reduces the dependence on human resources, not only saving a large amount of labor costs, but also, due to the simple operation method and extremely low learning cost, greatly reducing the personnel training costs.

[0044] Summary: The advantages of the present invention are obvious. First, the mobility and rapid deployment ability of the UAV enable it to cover a large area of the levee region in a short time. Second, the high-precision positioning system and laser emitter carried by the UAV can provide more accurate measurement data than traditional sensors. In addition, the use of a high-definition camera provides intuitive visual evidence for deformation monitoring, making the monitoring results more reliable.

[0045] However, this method also faces some challenges. For example, the flight of the UAV is restricted by weather conditions, and bad weather may affect the execution of the monitoring task. At the same time, the fields of view of the laser emitter and the camera may be blocked by the vegetation on the levee surface, which requires considering the influence of vegetation when selecting measurement points. In addition, image processing and data analysis require professional technical support, which places higher requirements on the technical level of the operators.

[0046] To overcome these challenges, the following measures can be taken. First, select a suitable weather window for monitoring to avoid the impact of adverse weather on UAV flight and data collection. Second, by setting up multiple measurement points on the levee and combining the multi-angle shooting ability of the UAV, the impact caused by vegetation occlusion can be reduced. Finally, strengthen the training of operators, improve their technical level, and ensure that they can proficiently use image processing and data analysis software.

[0047] Generally speaking, the levee deformation monitoring method based on the UAV platform has advantages that cannot be compared with traditional methods. It not only improves the accuracy and efficiency of monitoring, but also reduces the cost and complexity of monitoring. Through continuous technological innovation and practical exploration, this method is expected to become the mainstream technology for levee deformation monitoring in the future.

[0048] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be modified or equivalently replaced, and any modification or partial replacement without departing from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims

1. The method of monitoring levee deformation by laser spotting with drones. The levee includes a levee body set on the levee foundation. The drone carries a flight controller, a camera mounted on a camera gimbal, a laser transmitter, and a GNSS module and / or RTK module for determining the three-dimensional positioning information of the drone. The embankment body and embankment foundation are collectively referred to as the embankment body; the structures at the embankment body are divided into through-embankment structures and appendages according to whether they cross the embankment. The structures that cross the embankment are through-embankment structures, and the structures that do not cross the embankment are appendages. Slope protection structures are set up on both sides of the embankment body, and the slope protection structures belong to appendages; there is a embankment crest on the top of the embankment body, and the embankment crest is part of the embankment body; Features Follow these steps in order: The first step is for the survey personnel to determine the number and location of the key monitoring points of the embankment deformation according to the specific conditions of the embankment structure, and to apply deformation monitoring targets for drone identification at each key monitoring point of the embankment deformation; The deformation monitoring target is an annular structure, including a solid circle center and three concentric rings with different diameters. The radius of the solid circle center is r1, the ring width is r2, and the distances from the inside to the outside of the three concentric rings to the solid circle center are d1, d2 and d3 respectively. The concentric ring with the smallest diameter is called the first ring, the concentric ring with the largest diameter is called the third ring, and the concentric ring with a medium diameter is called the second ring; The second step is to determine the measurement points that correspond to the key monitoring points of each levee deformation. When determining the measurement points, the operator controls the drone equipped with a fixed-angle laser transmitter to emit lasers to each deformation monitoring target on the levee one by one. For a specific deformation monitoring target, the laser forms a bright laser spot on the irradiated surface of the deformation monitoring target; the spatial position of the UAV is adjusted so that the laser spot coincides with the center of the deformation monitoring target; the camera gimbal angle of the UAV is adjusted so that the deformation monitoring target is completely photographed by the camera of the UAV; the three-dimensional spatial position of the UAV and the camera gimbal angle at this time are recorded and stored as the waypoint information of the UAV, and the three-dimensional spatial position is called the measuring point; the second step is to obtain the measuring points corresponding to all monitoring points; The third step is to plan the inspection flight route; the survey personnel smoothly connect all the drone survey points as the navigation waypoints of the drone flight route to obtain the inspection flight route of the drone for inspecting the embankment; the inspection flight route is stored in the drone; the inspection flight route has a starting point and an end point, and the flight controller stores the three-dimensional positioning information of the starting point and the end point; The fourth step is inspection; The survey personnel determine the inspection frequency according to the needs; during daily inspections, the drone arrives at each survey point one by one along the inspection flight route; when arriving at any survey point, the drone hovers, adjusts the fuselage orientation and camera gimbal angle according to the waypoint information corresponding to the survey point, and emits laser at the same spatial angle. The laser coincides with the three-dimensional spatial position of the laser emitted by the drone when the survey point is determined in the second step, and forms a bright laser spot on the illuminated surface. At this time, the camera carried by the drone shoots the deformation monitoring target, and after the shooting is completed, it flies to the next survey point; after completing the shooting task of all survey points, the drone returns; The fifth step is data analysis; The surveyor exports the deformation monitoring target image taken by the drone for review; If the bright laser spot in the photo coincides with the center of the deformation monitoring target, it means that no deformation has occurred at the corresponding key monitoring point of the embankment deformation; If the bright laser spot in the photo does not coincide with the center of the deformation monitoring target, it means that deformation has occurred at the corresponding key monitoring point of the embankment deformation.

2. The method for monitoring embankment deformation by using laser spotting by unmanned aerial vehicle according to claim 1 is characterized by: In the fifth step, when deformation has occurred at the key monitoring points of the embankment, the surveyors will classify the deformation degree into mild deformation, moderate deformation and severe deformation according to the following principles: When the bright laser spot in the photo is located between the center of the deformation monitoring target and a ring or on a ring, the deformation degree of the corresponding key monitoring point of the embankment deformation is classified as slight deformation; When the bright laser spot in the photo is located between the first and second rings of the deformation monitoring target or on the second ring, the deformation degree of the corresponding key monitoring point of the embankment deformation is classified as moderate deformation; When the bright laser spot in the photo is located between the second and third rings of the deformation monitoring target or on the third ring, the deformation degree of the corresponding key monitoring point of the embankment deformation is classified as severe deformation.

3. The method for monitoring levee deformation by using unmanned aerial vehicle laser marking according to claim 1 is characterized by: The first step is: the survey personnel select several key monitoring points of embankment deformation at the following monitoring locations: ① The junction between the embankment and the embankment body not covered by the appendages; ② The junction between the embankment penetrating objects and the appendages covering the embankment body; ③The junction between the appendage and the main body of the embankment; ④The junction between appendages; ⑤The deformation joints of the embankment body or slope protection structure; ⑥ Top of the dike; 7. The middle section of the embankment; ⑧ Areas with historical structural problems or known geological weaknesses; ⑨The connection between the embankment body and the embankment.

Images