Method for surveying and mapping desert abdominal terrain through unmanned aerial vehicle

Abstract

The invention belongs to the technical field of topographic surveying and mapping, and particularly discloses a method for surveying and mapping desert abdominal terrain by an unmanned aerial vehicle, which comprises the following steps of: firstly, arranging image control points in a surveying area according to control points; then controlling the unmanned aerial vehicle to fly along the flight route, and shooting the image control point at the same time; carrying out live-action three-dimensional modeling by using ContextCapture software by a worker; coordinate information in the three-dimensional model is extracted through Qinghua three-dimensional EPS software; converting the coordinate information into coordinate data by using CASS software, and finally drawing a cross section graph of the roadbed by using Autocad2016 software. In order to solve the problem that the task load of manual measurement work is large at present, a measurement area is shot through an unmanned aerial vehicle, and data fusion is carried out through software such as ContextCapture modeling software and Qinghua three-dimensional EPS software, so that original field dotting of a total station is converted into indoor three-dimensional mapping, and the problem that when measurement work is carried out in a desert area, the measurement efficiency is high is solved. And the working efficiency is low due to potential safety hazards of personnel, large measurement task load and high labor intensity.

Description

Technical Field

[0001] The invention relates to the technical field of terrain surveying and mapping, and in particular to a method for surveying and mapping desert hinterland terrain using an unmanned aerial vehicle. Background Art

[0002] The original ground resurvey is an important process in highway construction. Its resurvey accuracy, density and work efficiency play a vital role in the subsequent construction and engineering measurement of the project. Usually, the original ground resurvey work mainly adopts the total station and RTK mode. This method has problems such as high labor intensity of field workers, complex procedures, time-consuming and high costs, which is particularly obvious for mountainous areas with narrow and long lines and complex terrains, as well as desert areas with harsh environments.

[0003] The traditional measurement method of total station and RTK mode is used for original ground re-survey, which has low work efficiency, small measurement point density and great difficulty in precision control. In order to improve the efficiency of original ground re-survey and reduce the labor intensity of field workers, it is necessary to design a method for UAV mapping of desert hinterland terrain to solve the problem of safety hazards for workers and low work efficiency caused by large manual measurement tasks and high labor intensity when conducting survey work in harsh environments such as deserts. Summary of the invention

[0004] The purpose of the present invention is to provide a method for mapping the hinterland terrain of the desert by using an unmanned aerial vehicle, so as to solve the problems of potential safety hazards for workers when performing surveying work in harsh environments such as deserts, large manual surveying tasks, high labor intensity and low work efficiency.

[0005] To achieve the above object, the present invention provides a basic solution: a method for mapping the desert hinterland terrain using an unmanned aerial vehicle, comprising the following steps:

[0006] S1: When starting the original ground resurvey, the field staff will first prepare the UAV route data and plan the route: determine the UAV control point in the survey area in the heart of the desert, enter the control point coordinates in the flight control platform, set the survey width, and select the appropriate flight altitude according to the ground resolution to complete the UAV route planning;

[0007] S2: Field workers set up image control points and checkpoints in the survey area in the heart of the desert, and input the coordinates of the image control points into the flight control platform. At the same time, the vertical coverage overlap rate of the drone images is set to 70%, and the horizontal coverage overlap rate is set to 60%. The field workers control the drone to fly along the planned flight route and take pictures of the image control points at the same time.

[0008] S3: In-house staff use ContextCapture 3D modeling software combined with POS system and image control points to perform real-scene 3D modeling.

[0009] S4: The office staff imports the real-scene 3D modeling into Tsinghua 3D EPS software to extract the 3D coordinate information in the real-scene 3D model;

[0010] S5: The office staff uses Southern CASS software to convert the three-dimensional coordinate information into coordinate data. Finally, the office staff can draw the roadbed cross-section diagram based on the coordinate data using Autocad2016 drawing software.

[0011] The beneficial effects of the present invention are as follows: (1) The present invention uses a drone to quickly measure the construction area, thereby reducing the labor intensity of surveyors and ensuring the safety of surveyors, thereby improving work efficiency; (2) Using ContextCapture for three-dimensional real-scene modeling can truly and accurately reflect the geographical environment of the construction site, making it easier for workers to guide construction; (3) The three-dimensional coordinate information extracted by Tsinghua 3D EPS software is convenient for later drawing of roadbed cross-section diagrams, performing engineering quantity calculations, and other tasks, thereby assisting on-site construction.

[0012] Option 2 is the preferred basic option. In S2, field workers evenly arrange image control points at intervals of 100 m within the measurement range, and the image control points are arranged in an "S" shape. Arranging the image control points in an "S" shape can ensure that the spacing between the image control points is moderate and evenly covers the entire measurement area, making the final measurement result more accurate.

[0013] Option 3 is the preferred basic option. In S2, when the drone takes pictures, it will shoot all the image control points twice, with each shooting lasting no less than 30 seconds and the shooting interval being 1 second. The two shooting results will be compared, and the error will be carried out with an accuracy of no more than 5 cm in plane error and no more than 5 cm in geodetic elevation error. If it does not meet the requirements, an additional measurement will be conducted.

[0014] Option 4 is the preferred basic option. In S2, after the UAV completes its flight mission, field staff will check whether all image control points exist in the image data taken by the UAV. If any are missing, the missing parts will be retaken to prevent the omission of image control points, which will affect the final measurement accuracy.

[0015] Solution 5: This is the preferred basic solution. In S3, the steps to build a real-scene 3D model using ContextCapture software are as follows:

[0016] A: First, create a new project in ContextCapture software, and name the project directory in English;

[0017] B: After creating the project, click Add Image to upload the image data of all image control points;

[0018] C: After adding the image, if the sensor size is not read, manually modify the sensor size to 13.2mm;

[0019] D: Select the spatial reference system according to the actual location of the flight area;

[0020] E: Input the measured GCP coordinate elevation data into ContextCapture. After importing the GCP coordinates, click Summary and then Submit Spatial Triangulation.

[0021] Using ContextCapture software for 3D real-scene modeling can truly, accurately and intuitively reflect the geographical environment of the construction site, making it easier for staff to guide construction in the later stages.

[0022] Solution 6: This is the preferred basic solution. In S3, after the ContextCapture software completes the spatial triangulation, it performs image control point puncturing. The operation steps are as follows:

[0023] Step 1: Click Measure in the ContextCapture software, select the imported image control point, move the mouse to the image control point position and click;

[0024] Step 2: After all the image control points are punctured, select Use image control point adjustment and submit the spatial triangulation again;

[0025] Step 3: After the spatial triangulation is completed, click New Reconstruction Project, then click Spatial Architecture, select the coordinate system, submit the production after the settings are completed, and select the 3D grid as the destination;

[0026] Step 4: Select osgb as the format and submit it. After production is completed, you can get the real-life 3D model of the survey area.

[0027] Puncturing points after successfully completing free-net spatial triangulation can greatly reduce the workload of point selection. The real-scene 3D model generated again after puncturing the image control points can correct the previous real-scene 3D model based on the punctured image control points, thereby improving the imaging accuracy of the model.

[0028] Solution 7 is the preferred basic solution. In S2, field workers check whether the image data taken by the drone is clear. If not, they need to adjust the flight altitude and re-shoot the image control points, thereby ensuring the shooting quality.

[0029] Option eight is the preferred basic option. In S3, the internal staff conducts a texture accuracy analysis on the 3D real-scene model. If the 3D model is clear and detailed, without large-scale voids, distortions, structural loopholes, and relatively complete road signs, and the height, shape, position, and relationship of buildings, transportation facilities, and vegetation are correct, and there is no obvious streaking, and the model’s lighting effect and overall color tone are good, it is judged to be qualified, ensuring the imaging accuracy of the real-scene 3D model.

[0030] Option nine is the preferred basic option. In S3, if the three-dimensional error does not exceed 5 cm, it is qualified. If it is unqualified, it is necessary to adjust the image control points and the flight altitude and re-photograph the image control points; this can reduce the error and thus improve the accuracy of the three-dimensional model.

[0031] Plan 10 is the preferred basic plan. In S5, the internal staff uses the Road Surveying and Design Master software to convert the three-dimensional coordinate information into coordinate data, and compare it with the data converted by the Southern CASS software; the coordinate data converted by the Southern CASS software and the Road Surveying and Mapping Master software are compared. If the comparison results are inconsistent, the image control points need to be re-photographed to ultimately reduce the error of the coordinate information and facilitate the drawing of the roadbed cross-section diagram. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the layout of image control points in a method for unmanned aerial vehicle surveying and mapping the desert hinterland terrain of the present invention;

[0033] Figure 2 It is a scene map of painting image control point marks in a method for unmanned aerial vehicle surveying and mapping desert hinterland terrain of the present invention;

[0034] Figure 3 The present invention is a flow chart of a method for using an unmanned aerial vehicle to survey and map the terrain of a desert hinterland. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below through specific embodiments:

[0036] Example

[0037] A method for mapping the desert hinterland terrain using an unmanned aerial vehicle, such as Figures 1 to 3 The following steps are shown:

[0038] S1: When starting the original ground resurvey, the field staff will first prepare the UAV route data and plan the route: determine the UAV control point in the survey area in the heart of the desert, enter the control point coordinates in the flight control platform, set the aerial survey width, and select the appropriate flight altitude based on the ground resolution. The UAV route data preparation and route planning work can be completed. The field staff refers to the staff who collect field data.

[0039] S2: Field staff will set up image control points and check points in the survey area in the heart of the desert. The image control points are evenly arranged at intervals of 100m within the survey range, and the image control points are arranged in an "S" shape. Then the coordinates of the image control points are input into the flight control platform. At the same time, the longitudinal coverage overlap rate of the drone images is set to 70%, and the lateral coverage overlap rate is set to 60%. The field staff will control the drone to fly along the planned flight route and shoot the image control points at the same time. All image control points will be shot twice, with each shooting time of no less than 30 seconds and an interval of 1 second. The two shooting results will then be compared, and the error will be carried out according to the accuracy of no more than 5cm in plane error and no more than 5cm in geodetic elevation error. If it does not meet the requirements, an additional measurement will be made. After the drone completes the flight mission, the field staff will check whether all image control points exist in the image data taken by the drone. If any are missing, the missing parts will be supplemented.

[0040] S3: In-house staff use ContextCapture software (ContextCapture is a 3D real-scene modeling software that can quickly generate 3D models based on captured footage) to combine the POS system and image control point measurement data for real-scene 3D modeling. First, create a new project in ContextCapture software. The project directory name is in English. After the project is created, click Add Image to upload the image data of all image control points. After adding the image, if the sensor size is not read, manually modify the sensor size to 13.2mm, select the spatial reference system according to the actual location of the flight area, and then enter the measured image control point coordinate elevation data into the ContextCapture software. In , after importing the coordinates of the image control points, click Overview and then submit spatial triangulation. After completing spatial triangulation, puncture the image control points. First, click Measure in the ContextCapture software, select the imported image control points, move the mouse to the image control point position and click; then after all the image control points are punctured, select Use image control point adjustment and submit spatial triangulation again. After the spatial triangulation is completed, click New Reconstruction Project, then click Spatial Architecture, select the coordinate system, submit production after the settings are completed, select 3D grid for the purpose, and finally select osgb for the format, then submit. After the production is completed, you can get the real-life 3D model of the survey area; internal staff refers to the staff who perform data processing and graphics generation.

[0041] S4: The office staff imports the real-life 3D modeling into Tsinghua 3D EPS software (Tsinghua 3D EPS is a 3D mapping software that can be used for land surveying, engineering design and other tasks) to extract the 3D coordinate information in the real-life 3D model.

[0042] S5: The three-dimensional coordinate information extracted by the office staff through Tsinghua 3D EPS software is converted into coordinate data using Southern CASS software (Southern CASS is a digital surveying and mapping data acquisition software) and Road Surveying and Design Master software (Road Surveying and Design Master is a digital surveying and mapping data acquisition software, including full-line road surveying and design, cross-section and engineering quantity, tunnel section analysis, office data, local curve surveying and design, common measurement and calculation tools and other systems) and compared. If the comparison results are consistent, the office staff can finally use Autocad2016 software (a drawing software for drawing two-dimensional and three-dimensional graphics) to draw the roadbed cross-section diagram based on the coordinate data. If the comparison results are inconsistent, the image control points need to be re-photographed.

[0043] Finally, the construction workers can calculate the project quantity based on the drawn roadbed cross-section diagram.

[0044] In summary, the use of UAV oblique photography technology for terrain surveying and mapping in desert areas through the above method not only ensures the safety of personnel when conducting surveying work in harsh environments such as deserts, but also saves manpower and reduces labor intensity; through the ContextCapture modeling software, Tsinghua 3D EPS software, Southern CASS software and Autocad2016 drawing software, the data is integrated to realize the transformation of mapping work from field marking with total station to indoor stereo mapping; finally, a macro-micro integrated three-dimensional space scene of "terrain + image + model + vector" is constructed, which is convenient for construction units to carry out on-site planning, construction management and engineering quantity calculation.

[0045] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for mapping desert hinterland terrain using an unmanned aerial vehicle, characterized in that: The following steps are involved: S1: When starting the original ground resurvey, the field staff will first prepare the UAV route data and plan the route: determine the UAV control point in the survey area in the heart of the desert, enter the control point coordinates in the flight control platform, set the survey width, and select the appropriate flight altitude according to the ground resolution to complete the UAV route planning; S2: Field workers set up image control points and checkpoints in the survey area in the heart of the desert, and input the coordinates of the image control points into the flight control platform. At the same time, the vertical coverage overlap rate of the drone images is set to 70%, and the horizontal coverage overlap rate is set to 60%. The field workers control the drone to fly along the planned flight route and take pictures of the image control points at the same time. S3: In-house staff use ContextCapture 3D modeling software combined with POS system and image control points to perform real-scene 3D modeling. S4: The office staff imports the real-scene 3D modeling into Tsinghua 3D EPS software to extract the 3D coordinate information in the real-scene 3D model; S5: The office staff uses Southern CASS software to convert the three-dimensional coordinate information into coordinate data. Finally, the office staff can draw the roadbed cross-section diagram based on the coordinate data using Autocad2016 drawing software.

2. The method for mapping the desert hinterland terrain using an unmanned aerial vehicle according to claim 1, characterized in that: In S2, field workers evenly arrange image control points at intervals of 100 m within the measurement range, and the image control points are arranged in an "S" shape.

3. The method for mapping the desert hinterland terrain using an unmanned aerial vehicle according to claim 1, characterized in that: In S2, when the drone takes pictures, it takes pictures of all image control points twice, each time for no less than 30 seconds, and the shooting interval is 1 second.

4. The method for mapping the desert hinterland terrain using an unmanned aerial vehicle according to claim 1, characterized in that: In S2, after the UAV completes its flight mission, field staff will check whether all image control points in the image data taken by the UAV exist. If any are missing, the missing parts will be retaken.

5. The method for mapping the desert hinterland terrain using an unmanned aerial vehicle according to claim 1, characterized in that: In S3, the steps to build a real-world 3D model using ContextCapture software are as follows: A: First, create a new project in ContextCapture software, and name the project directory in English; B: After creating the project, click Add Image to upload the image data of all image control points; C: After adding the image, if the sensor size is not read, manually modify the sensor size to 13.2mm; D: Select the spatial reference system according to the actual location of the flight area; E: Input the measured GCP coordinate elevation data into ContextCapture. After importing the GCP coordinates, click Summary and then Submit Spatial Triangulation.

6. The method for mapping the desert hinterland terrain using an unmanned aerial vehicle according to claim 1, characterized in that: In S3, after the ContextCapture software completes the spatial triangulation, it performs image control point puncturing. The operation steps are as follows: Step 1: Click Measure in the ContextCapture software, select the imported image control point, move the mouse to the image control point position and click; Step 2: After all the image control points are punctured, select Use image control point adjustment and submit the spatial triangulation again; Step 3: After the spatial triangulation is completed, click New Reconstruction Project, then click Spatial Architecture, select the coordinate system, submit the production after the settings are completed, and select the 3D grid as the destination; Step 4: Select osgb as the format and submit it. After production is completed, you can get the real-life 3D model of the survey area.

7. The method for mapping the desert hinterland terrain using an unmanned aerial vehicle according to claim 1, characterized in that: In S2, field staff check whether the image data taken by the drone is clear. If not, the flight altitude needs to be adjusted and the image control points need to be re-photographed.

8. The method for mapping the desert hinterland terrain using an unmanned aerial vehicle according to claim 1, characterized in that: In S3, office staff conducts model texture accuracy analysis on 3D real-scene models.

9. The method for mapping the desert hinterland terrain using an unmanned aerial vehicle according to claim 1, characterized in that: In S3, if the three-dimensional error does not exceed 5cm, it is qualified. If it fails, it is necessary to adjust the image control points and flight altitude and re-shoot the image control points.

10. The method for mapping the desert hinterland terrain using an unmanned aerial vehicle according to claim 1, characterized in that: In S5, the office staff uses the Road Surveying and Design Master software to convert the three-dimensional coordinate information into coordinate data, and compare it with the coordinate data converted by the Southern CASS software. If the comparison results are inconsistent, the image control points are re-photographed.

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