1. The airborne lidar system is abbreviated as LIDAR in English. It can measure a larger range of ground objects and has a high resolution. It can quickly and accurately detect geographic data information in various areas. At the same time, the airborne lidar system can also combine cloud data processing technology to establish ground models and digital surface models to provide relevant personnel with more professional data results. Based on the author's actual work experience, this article will carry out a simple analysis of the application of airborne lidar systems in the field of surveying and mapping.
2 Application status of the airborne lidar system
Airborne lidar measurement technology first appeared in the aerospace field in the United States and was used to measure the distance between objects. It has a history of more than 20 years. With the continuous improvement of the level of science and technology, the technical application level of the airborne lidar system has also been significantly improved, and it has been applied to the construction and development of other fields. At present, airborne lidar systems have occupied a certain market share in the global market in various fields, and the most representative countries include the United States, Germany and Canada [1]. Although it is relatively late to introduce airborne lidar systems in my country, the research progress in related aspects is relatively rapid, and it has been successfully applied to engineering construction in various fields such as topographic surveying, forest resource investigation and urban modeling. In addition, in the field of transportation, Chinese researchers are also widely applying related products such as vehicle-mounted laser scanning systems and three-dimensional laser scanning systems.
3 Overview of airborne lidar measurement technology
3. 1 Main features and performance
In the application process of airborne lidar measurement technology, it has the characteristics of high precision, high density, high efficiency, high coverage and high resolution. Specifically, the elevation accuracy of this technology can be controlled within 15cm during application. The point cloud data obtained in the application process can accurately reflect the topographic and landform characteristics of the survey area, and can assist surveyors to complete the actual elevation measurement operations, and obtain very accurate data [2].
In addition, the airborne lidar measurement technology mainly uses active measurement to measure the actual conditions of the measurement area. It can penetrate thin clouds and mist, and it is generally not restricted by weather and natural environment during use. , The degree of dependence on the external environment is low, and the relevant work can be carried out at night without being affected by time. At the same time, when the technology is applied to vegetation-rich areas, the measurement results will not be affected by vegetation, have strong penetrating power, and can directly measure the area under the vegetation.
3.2 Point cloud data processing of airborne lidar
Point cloud data processing mainly refers to the laser point cloud data, image data and ground base station data obtained through aerial shooting. The original data is converted, analyzed, and inspected by certain methods such as track calculation so that the final data obtained meets its use parameters and related requirements. Under normal circumstances, technicians will use the airborne lidar system to process most of the pulse point data, and obtain the three-dimensional data information of the measurement area, and build a three-dimensional data model on this basis.
4 Application of airborne lidar measurement in the field of surveying and mapping
4. 1 Application in traditional surveying and mapping engineering
In the process of applying airborne lidar measurement technology to traditional surveying and mapping fields, technicians use airborne lidar devices to quickly obtain accurate surface data and establish digital surface models. In fact, in the application process of traditional digital photogrammetry technology, some areas covered by vegetation are difficult to measure, and it is difficult to obtain accurate data information of related areas; while the process of using airborne lidar measurement technology In this way, it is not affected by vegetation cover, and you can get clear digital images by using related supporting equipment.
4. 2 Application in the field of traffic surveying and mapping
In the transportation field, the application of airborne lidar measurement technology is mainly to use LIDAR technology to obtain engineering models in the design process of railway and highway engineering, so as to provide correct calculation schemes and data for line designers and construction personnel. Be able to design more reasonable traffic routes, and be able to comprehensively estimate and understand earthwork related data. At the same time, in the construction of communication networks and pipelines in the transportation field, the airborne lidar system also has a high application value, which can provide good data information for it to ensure the effectiveness and rationality of the construction.
4. 3 Application in the field of electric power engineering surveying and mapping
In the field of power engineering, airborne lidar systems also have certain application value. In the construction of power transmission projects and power pipeline projects, a large number of LIDAR technology has been applied, and good results have been achieved. In the process of applying lidar technology, the staff can use the data and information measured by the technology to design the pipeline lines of the entire power system and improve the construction plan of the power engineering project. In addition, LIDAR technology also has certain application value in the process of grid deployment and maintenance management. In fact, in the process of designing power system lines, the LIDAR technology can be used to obtain topographic and landform information in the entire line layout area and to detect large-scale features that affect the wire design, providing a certain guarantee for the design work. In the area where the route passes, you may encounter densely forested areas. At this time, using LIDAR technology, you can calculate the area of felled trees and the total amount of wood produced. In addition, in the process of using LIDAR technology, the relevant data of elevation measurement points can also be analyzed and calculated through point extraction, filtering and denoising techniques, which lays the foundation for emergency repair and maintenance.
4. 4 Application in the field of marine surveying and mapping
In ocean surveying and mapping, it is mainly used for nearshore water depth measurement. The appearance of airborne laser sounding system is also different from traditional water depth measurement technology. It can quickly obtain the geospatial information and water depth topography of islands and reefs. The principle of airborne laser sounding is similar to the principle of dual-frequency echo sounding. Two kinds of laser beams are emitted from the aircraft to the sea surface. One is an infrared laser whose beam is directly reflected by the sea surface. The other is a blue-green laser beam. The sea surface is directly transmitted to the seabed and then reflected. The sea depth can be calculated by the time difference between the two different wavelengths of lasers being received. Today, when ocean development is increasingly valued, this dual-band laser sounding technology has broad application prospects.
4. 5 Applications in other surveying and mapping fields
In addition to the above-mentioned fields, airborne lidar measurement technology also has very important applications in many fields such as homeland security, urban planning, emergency systems, public utilities and environmental monitoring. Technical personnel in various fields use the airborne lidar system to effectively obtain accurate topographic and landform data, and on this basis, ensure the construction quality of related projects. For example, when the Wenchuan earthquake occurred in my country in 2008, relevant staff used airborne lidar measurement technology to measure the complex space where the earthquake occurred, and obtain the geographic data information of the post-disaster area
5 Development trend of airborne lidar
In the development of today’s society, airborne lidar actually belongs to a new type of sensor device, which uses a laser to detect the distance between objects in the application process, and combines with related software to establish a high-precision digital representation model, So that the staff can understand the geographic location information of the object and other related data. As the technology is widely used in various fields, it will also be effectively combined with advanced technologies such as CCD and POS to increase its own application value. In addition, airborne lidar can also be effectively combined with various advanced technologies in the field of remote sensing, laying a good foundation for enhancing data processing capabilities.www.isurestar.net