Research On Single Base Station CORS Enhancing Accuracy And Usability Of UAV Oblique Photogrammetry

In recent years,with the continuous development of UAV and flight control technology,and continuous improvement of oblique photogrammetry theory and processing software,UAV oblique photogrammetry technology has been widely used in land and resources management,urban planning,emergency command and geological prevention,etc.It has unparalleled technological advantages in many fields,especially in 3D reality modeling and rapid large-scale mapping,leading another technological revolution in the field of surveying and mapping.At the same time,it also provides a numerical basis for spatial information for the construction of major projects such as smart cities,"multiple discipline integration " and " integration of real estate " currently underway in China.With the continuous expansion of the breadth and depth of the application of this technology,users not only use it for the rapid acquisition of spatial information and modeling,but also have higher requirements such as on its accuracy,reliability and availability,as well as production costs,operating cycle and labor input and intensity.The use of satellite navigation and positioning technology represented by RTK / PPK to support and enhance the UAV oblique photogrammetry operation mode has attracted increasing attention and has also become a hotspot of recent research.However,the long-term application of RTK / PPK in this field mostly stays in the user's own base station operating mode,and there are many limitations in terms of accuracy,availability,and operating efficiency.Considering that China has established a large number of Continuously Operating Reference System(CORS),which can provide long-term stable base station data sources.Therefore,the research on the theory and method of single-base station CORS enhanced UAV oblique photogrammetry has important theoretical,application value and promotion significance for further improving the performance and usability of UAV oblique photogrammetry technology,as well as the promotion and expansion of the conventional service content of the CORS system,which are complementary to each other.This article starts with a single base station CORS system.Based on the study of GNSSsupported aerial triangulation theory and analysis of the characteristics of RTK / PPK technology,it focuses on the method of enhancing the accuracy and usability of UAV oblique photogrammetry with PPK technology based on single base station CORS.The main research contents are as follows:(1)Through in-depth understanding of the single base station CORS system,GNSSsupported aerial triangulation principle and analysis of the characteristics of RTK / PPK technology,it is proposed to use the PPK technology to enhance the UAV oblique photogrammetry based on the single base station CORS system to compensate for the problem of the signal interruption of RTK technology in complex environments and Self-supporting base station operation methods have heavy tasks and high technical requirements.(2)Focus on study of key technologies such as the PPK solution of the synchronous observation data of single base station CORS system and airborne GNSS receiver,postprocessing to obtain the three-dimensional coordinates of the camera photography center at the time of exposure,and the construction of three-dimensional real scene models.Based on existing software,hardware equipment and theory,the data processing flow based on single base station CORS system using PPK technology to enhance UAV oblique photogrammetry is elaborated in detail.(3)Through focusing on data processing methods such as sliding Lagrange polynomial interpolation,writing the data post-processing program based on MATLAB language,based on PPK calculation,to obtain high-precision image position information data at the exposure time for aerial triangulation and 3D reconstruction,with a small number of ground control points to improve the accuracy and efficiency of 3D reconstruction.(4)Based on the single base station CORS system,the PPK technology is used to enhance the UAV oblique photogrammetry technology to construct a three-dimensional reality model.The accurate analysis of the three-dimensional reality model constructed by different experimental schemes summarizes the accuracy and availability of the operation method.