Analysis of The Application of Unmanned Aerial Vehicle Surveying Technology in Construction Engineering Measurement

The current society has entered the information age, and science and technology have become the core force driving the improvement of social productivity. Various advanced equipment and technical solutions are continuously being implemented in the production and operation processes of various industries. Drones are high-tech products of the new era. With their flexible and mobile characteristics and convenient operation, they have been widely used in many industries. By integrating drone equipment with traditional engineering surveying technology, drone surveying technology is formed, achieving the innovation and upgrading of engineering surveying methods.

Building project surveying is a very crucial part of the entire process of building project construction. The data obtained through measurement directly affects the quality of work in various aspects such as engineering planning, construction, and completion acceptance. In recent years, the scale of domestic building projects has been continuously expanding, and many engineering projects have complex terrain conditions. The traditional manual surveying mode has a long operation cycle, and personnel cannot reach some dangerous areas. Surveying operations are prone to human errors and have limited overall efficiency. Facing the continuously improving surveying requirements of the industry, the emergence of drone surveying technology effectively compensates for the shortcomings of traditional measurement methods.

To fully exert the practical effectiveness of drone surveying technology, it is necessary to combine the real working scenarios of building project surveying, clarify the core advantages of this technology, sort out the practical operation points in various businesses, solve various practical problems encountered in surveying operations, and thereby provide strong technical support for building project surveying work, promoting the high-quality development of the construction industry.

1. Advantages of using drone surveying technology in building project surveying

1.1 Fast collection of building-related information data

The drone surveying system is equipped with specialized data collection modules and information transmission modules, which can quickly complete data collection in the surveyed area and complete data transmission in real time, significantly improving the overall efficiency of surveying. Technicians can quickly obtain the original survey data to carry out subsequent analysis work. In building projects, there are many construction areas with complex hydrogeological conditions, and it is difficult for personnel to conduct on-site surveys. Using traditional surveying equipment is difficult to carry out operations in such scenarios. In this case, operators can control the drone to complete the exploration of complex areas and efficiently collect various basic information such as hydrology and geology within the area.

Drones not only can complete the data collection work, but also can conduct preliminary preprocessing on the collected original data and then directly send the processed information to the technical staff at the rear through the transmission module, achieving rapid collection and immediate transmission of construction area information, greatly reducing the time spent on surveying operations. Surveyors can use the imaging and mapping functions of the drone to conduct scans of the construction area from above, completing the surveying operation. During the operation, it is necessary to minimize the interference of external environmental factors on the surveying results to ensure the accuracy of the data obtained by the drone surveying. Compared with the traditional manual on-site surveying mode, drone surveying eliminates the need for personnel to frequently return to the site and make on-site marks and records, especially in large-scale construction sites, the advantage of data collection speed will be further highlighted.

1.2 Large-scale observation of survey objects

When the overall scale of a building project is large, traditional surveying methods are prone to measurement errors and the reliability of surveying results is difficult to guarantee. Drone surveying technology can effectively solve the practical problems of large-scale engineering surveying. When conducting high-altitude remote sensing monitoring by drones, relying on real-time image transmission, remote control, and automatic focusing functions, operators do not need to frequently change the working position, but can complete the exploration of the entire construction area.

By leveraging the characteristics of remote operation of drones, it can effectively avoid many surveying difficulties in the construction site. Many construction sites have steep slopes, deep pits, dangerous slopes and other locations that are difficult for people to approach. Manual measurement not only has high operational difficulty but also brings certain safety risks. Drones can directly fly over the above dangerous areas to complete the observation, which not only ensures the safety of the staff but also effectively improves the overall surveying efficiency. When facing large clusters of buildings or large construction sites, drones can cover a wide range of surveying areas at once and continuously obtain the overall situation of the site, avoiding the data stitching deviation caused by traditional segmented surveying, and being more suitable for the surveying operation requirements of large-scale construction projects.

1.3 Security of Data

Drones surveying belongs to a rapidly developing advanced surveying method in recent years. It can complete difficult surveying tasks in restricted spaces and the entire system has a complete data security guarantee capability. The drone surveying system integrates data security encryption technology, data encoding storage module and firewall-related functions, comprehensively strengthening the security protection level of surveying data. Even when conducting long-distance surveying operations, the data collected through the information transmission module during the return process is not easily affected by external interference, reducing the risks of data loss and data tampering.

The data generated by construction project surveying includes a large amount of core engineering data such as site topography, building layout and project planning. If the data is leaked or the transmission process is damaged, it will directly affect the progress of the entire project. In the traditional surveying mode, a large number of paper records and manual copying circulation are prone to data loss. After the data is collected by drone surveying, it is encrypted and transmitted directly stored in the system, reducing the security risks brought by human replication and circulation, and ensuring the complete and safe delivery of the surveying results to the technicians.

2 Application of Drone Surveying Technology in Urban Construction Project Surveying

2.1 Application of Construction Project Surveying Technology in Low-altitude Measurement Operations

Different construction projects are located in different geographical locations, and the terrain and landform of the construction site and the working conditions vary greatly. Some projects have large terrain undulations and many obstacles, and ordinary high-altitude aerial photography methods are difficult to play a role. The accuracy of the surveying results cannot be guaranteed. Drone surveying technology can carry out low-altitude surveying operations, with less external environmental constraints. Even if the terrain conditions are complex, the surveying task can still be completed smoothly, and data collection can be carried out quickly and preliminary data processing can be carried out. When encountering complex terrain construction projects, choosing the low-altitude measurement scheme of drones is a very reasonable choice.

The low-altitude measurement system has a high imaging resolution and can clearly restore the real situation of the surveying area, meeting the requirements of large-scale mapping-related work. At the same time, the low-altitude measurement system also has outstanding capabilities in data detection and verification. Relying on digital cameras and matching verification software as well as photo overlap relationship functions, it can effectively correct the measurement errors caused by the drone flight trajectory and reduce the problem of measurement accuracy decline due to the deviation of camera posture angle. The low-altitude measurement system can also reduce the image overlap problem in urban surveying operations and create conditions for the stable flight of drones. At the same time, the drone surveying system is equipped with map-at/es software, further improving the automation operation level of the entire equipment and promoting the continuous maturity of low-altitude drone surveying technology.

In the actual operation of low-altitude surveying, the influence of the environment should also be fully considered. Trees, high-rise buildings, power lines and other obstacles will interfere with the flight of drones. Before the operation, it is necessary to conduct on-site reconnaissance of the surveying area, plan a reasonable flight route, avoid various obstacles, and prevent the aircraft from colliding and damaging, to ensure the smooth progress of the surveying work.

2.2 Comprehensive Collection of Urban Construction Project Information

Data collection is the basis of surveying work, and the quality of the collected data directly determines whether the subsequent data analysis work is accurate. During the process of drone surveying and mapping, it is necessary to conduct scientific screening on the collected raw data, eliminating invalid data that deviates from the actual situation, to ensure the authenticity and reliability of the surveying results. It is not enough to conduct analysis based solely on the data collected by a single flight of the drone. Multiple surveying operations need to be carried out, and the site information needs to be repeatedly collected.

Multiple flight surveying can make up for the data gaps caused by the drone's flight route. Any surveying technology inevitably has certain errors. Only through multiple surveys can the multiple sets of surveying results be compared and verified to further improve the accuracy of the data. After the data collection is completed, it is necessary to enter the data processing stage. Before the widespread use of drone surveying, the processing of surveying data mainly relied on manual work. Although the manual processing mode has certain practicality, it is inefficient when dealing with high-volume surveying data from modern construction projects, and the processing accuracy is difficult to meet the demands of the times. Simply increasing the number of staff to improve processing speed will directly increase the cost of project surveying.

Drone surveying technology effectively solves the practical contradiction of large-scale data processing. Not only is the data processing speed fast, but the processing results also have high credibility. The equipment can automatically complete the sorting, screening, and stitching of large amounts of images and point data, significantly reducing the workload of manual work, shortening the entire surveying process cycle, and reducing the labor cost of the project. However, after the automatic processing, technicians still need to review the results, identify errors generated in the automatic processing stage, and ensure the quality of the final surveying results.

2.3 Application in Oblique Photogrammetry

Oblique photogrammetry technology of drones is often used in the data collection work during the project completion stage. It can play a prominent role in the completion surveying scenarios. Oblique photogrammetry can stereoscopically restore the actual construction effect of the project and the true appearance of the building, allowing workers to intuitively experience the overall design effect of the project and obtain measurement data with high accuracy. It can retain the real texture information of the building and lay a solid foundation for the subsequent three-dimensional modeling work.

During the urban construction stage, oblique photogrammetry can also be used for engineering measurement, which can complete terrain information collection in a short time and overcome the shortcomings of traditional surveying technologies such as long cycle, slow operation speed, and insufficient measurement accuracy. On the one hand, it can ensure on-site construction efficiency, and on the other hand, it can present the surveying results in a visual form, laying a foundation for the project completion acceptance work. Compared with traditional orthophotos, oblique photogrammetry can simultaneously obtain image information of the building's top and sides, fully restoring the details of the building's facade, and is very suitable for surveying work in densely built-up urban areas.

The three-dimensional model obtained from oblique photogrammetry can also serve various aspects of engineering work. During the construction stage, it can be compared with the design drawings to check if there are any deviations in the actual construction; during the operation stage, it can be used to conduct building appearance inspections to check if the exterior walls and ancillary facilities are damaged, expanding the usage scenarios of the surveying results.

2.4 Acquisition of Image Data

The drone surveying system integrates multiple functional modules such as the aircraft and GPS positioning. The multiple modules work collaboratively, and within a short period of time, a large amount of raw data and image data of the surveying area can be obtained, laying a foundation for subsequent design, construction, and acceptance work. To obtain high-quality image data, it is necessary to combine the surveying accuracy requirements and the on-site working environment, reasonably match various functional modules, and the selection of the flight module will directly affect the quality of the captured images. Special attention should be paid.

In addition to the reasonable selection of hardware modules, it is also necessary to standardize the shooting operation process to ensure the quality of image collection. The aerial triangulation method can effectively improve the surveying effect and ensure the authenticity and reliability of the collected data. Properly setting the exposure delay time can reduce the interference caused by the drone's turning movement to the captured image, thereby further improving the accuracy of image acquisition. During actual operations, key parameters such as flight altitude, flight speed, and image overlap degree should be controlled. If the flight altitude is too high, the image resolution will be insufficient and detailed information will be lost; if the flight altitude is too low, it is prone to be interfered by obstacles. Inappropriate settings for the heading overlap and lateral overlap will lead to flaws in the later image stitching, affecting the overall mapping results. After the image collection is completed, it is necessary to classify and archive the image data to facilitate subsequent retrieval and use.

2.5 Air Triangulation Surveying

Air triangulation surveying is a very important technical means in urban construction engineering surveying. It calculates the relevant parameters of the surveying area through the image measurement and analysis method, and is an indispensable key step in the engineering surveying process. In the traditional mode, conducting air triangulation surveying is quite difficult and the operation process will generate a large amount of data, greatly increasing the workload of the surveying personnel. Combining drones and air triangulation surveying can effectively alleviate the work pressure of the staff.

However, the flight stability of the drone is limited. During the surveying operation, inevitable measurement errors will occur, resulting in poor matching effect of the image data. At the same time, the external wind direction will interfere with the flight attitude of the drone, causing the image rotation angle to be larger. In such cases, the operator needs to intervene manually, adjust the shooting angle, and improve the matching degree between the image and the actual geographical location. The data calculation process relies on professional software to complete the automatic processing of images, and the staff only needs to set the relevant image parameters in advance to obtain high-precision surveying data.

During the operation of drone air triangulation surveying, it is necessary to ensure that the connection points in the measurement area are scientifically and reasonably arranged, with the connection points evenly distributed throughout the surveying area. When adding connection points, try to place the point positions in the middle of the image to reduce the adverse effects of image edge deformation. Technicians need to pay attention to various error sources, check and verify the final results, and promptly correct the problems to ensure that the air triangulation surveying results meet the usage standards of the construction project.

Conclusion

Currently, all industries are actively promoting technological innovation, and the surveying and mapping industry is constantly introducing various new technologies, resulting in the emergence of multiple modern surveying methods. Among them, unmanned aerial vehicle (UAV) surveying technology is one that has achieved remarkable comprehensive application effects. From the advantages of technological application, it can be seen that the application scope of UAV surveying technology in the field of construction engineering measurement will continue to expand.

UAV surveying technology has multiple advantages such as fast data collection speed, support for large-scale observation, and high data security. It can be adapted to low-altitude measurement operations, building information collection, tilt photography modeling, image data acquisition, and aerial triangulation measurement, among other construction engineering measurement tasks. Compared with traditional surveying methods, UAV surveying can adapt to complex terrain conditions, reduce the labor cost of surveying operations, avoid some on-site operation safety risks, and improve the overall efficiency of surveying work.

However, we must also objectively recognize that UAV surveying technology is still affected by factors such as wind, obstacles, and the stability of the aircraft itself. During the operation, various errors will still occur, and it cannot be completely separated from manual intervention and result verification. In actual engineering projects, the results of UAV surveying cannot be directly relied upon. It is necessary to combine the actual project situation, reasonably plan the flight plan, and conduct preliminary on-site surveys to complete the automation process.