A Comparative Study Of 3D Modeling Accuracy Of Oblique Photography Based On Consumer Single Lens Unmanned Aerial Vehicle

With the rapid development of China's Smart City construction,three-dimension real scene model as the most significant part of urban spatio-temporal information,has been increasingly important.Especially the "14th Five-Year" basic surveying and mapping plan launched in 2020,while "China three-dimensionalreal scene Construction" is listed as part of content.At the same time,projects such as "multiple regulations in one" and "integration of land and house",which are currently underway,have also raised the demand for real-world 3D models to an unprecedented height.Therefore,how to achieve efficient and high-quality construction of real-world 3D models at different spatial scales has become a hotspot recently.Unmanned Aerial Vehicle(UAV)oblique photogrammetry,equipped with various types of cameras through different types of flight platforms,provides an effective solution for quickly constructing a real-world 3D model.Particularly,the consumer-grade unmanned aerial vehicles that have appeared in recent years are equipped with a single-lens oblique photography operation mode.Due to their low cost,easy handling,and flexible implementation,they have unparalleled advantages in 3D modeling in a small area.However,its accuracy,reliability and efficiency will be affected by various factors such as flight platform,camera parameters,aerial photography parameters,ground image control point layout strategy and flight control platform POS information in actual work.In order to further promote the application of this model,it is necessary to carry out analysis,research and corresponding accuracy evaluation on theseinfluencing factors,and then propose an optimized solution.This article focuses on the three-dimensional modeling with consumer-level single-lens oblique photogrammetry.Based on the analysis of various influencing factors of UAV oblique photogrammetry,starting from the perspective of air-ground collaboration,it focuses on the impact of ground image control point layout and its optimization strategy.In particular,it proposes corresponding solutions for uneven accuracy in dense areas of urban buildings.At the same time,under different application conditions,using the current mainstream satellite navigation and positioning technology,represented by real-time kinematics(RTK)and post-processing kinematics(PPK),to assist the ground to lay out image control points.Exploring the balance between cost and accuracy through different combined positioning methods and related experiments.The main research contents are as follows:(1)Discussing the technical route of UAV oblique photogrammetry,and comprehensively analyzing the characteristics of the flight platform,camera parameters,aerial parameters,image control point layout,POS information and other influencing factors for the key steps of the technical route implementation,especially the principle of using RTK and PPK to obtain position information in POS system.(2)Analyzing the geometric and collinear equations using photogrammetry to study the inherent relationship between the location accuracy of encryption points and the number and spatial distribution of image control points,and propose an air-ground joint layout and image control point optimization scheme to solve the drone oblique photography technology facing the city In dense building areas,there is a problem of uneven 3D modeling elevation accuracy,and consumer-grade drone oblique photography is used for field data collection and modeling verification.(3)In view of the large workload of image control layout and the difficulty of special survey area layout,the GNSS differential technology is introduced to select the survey area of school experiment building and dormitory building to simulate different urban geomorphic environment.Considering the concentration of image control points and GNSS difference methods such as RTK and PPK,a variety of orientation schemes were designed and the accuracy of 3d model was compared to investigate the implementation effect of single orientation.Moreover,this study verifies the accuracy and feasibility of combining GNSS orientation ofimage control points,which provides a reference for the 3d modeling work of oblique photogrammetry.