A Case Study Of UAV Low Altitude Photogrammetry

With the development of geographic information mapping technology, UAV technology has been applied to all aspects of the surveying and mapping industry. For example, the digital orthophoto which is produced by using low altitude UAV photography measurement technology, compared with the traditional ground surveying and remote sensing technology,has the advantages of fast and efficient, more detailed information and higher accuracy, and provides a more accurate and reliable data source for the land survey and geographical condition monitoring.In this thesis, based on the example of low altitude photogrammetry of UAV, the composition of UAV low altitude photogrammetry system, the advantages and disadvantages of UAV photography and the factors affecting the accuracy of the image are analyzed. It focuses on analyzing the production process of the orthophoto of the low-altitude UAV photogrammetry, and making a detailed study on the key technologies of the UAV image acquisition and processing. The method of generating digital orthophoto map by using Pix-4DMapper software was studied, and the accuracy of DOM mapping with different image control points was analyzed. Taking a county of Gansu Province as an example, this paper discussed the UAV industry large scale mapping, the technical problems of the image control point network setting and the image processing in the process of image producing and produced 1:2000 digital orthophoto map of the research area. The accuracy analysis was carried out by using ArcGIS software to generate orthophoto, and a relatively reasonable image control point selection scheme was obtained.The results of this study to improve the digital orthophoto mapping efficiency and accuracy by using the UAV low altitude photogrammetry technology have a reference value.