Empirical Study On The Mapping Precision Based On UAV Low-altitude Photogrammetry

With some advantages of high-efficient, high resolution, low-cost, low risk, repeatable,etc, UAV (Unmanned Aerial Vehicles) technology has been widely used in geodetic surveying,disaster monitoring, weather monitoring, military applications, resource surveying, etc.Compared with some traditional measure methods, the manned aircraft airborne remotesensing and satellite remote sensing, UAV low-altitude photogrammetry technology canrapidly acquire high resolution remote-sensing images in large areas, conventional aerialdifficult areas and natural disaster areas which improves the efficiency of producing digitalproducts, such as DLG(Digital Line Graphic), DEM(Digital Elevation Model), DOM(DigitalOrtho Map), etc. It has become one of the important technical means of acquiring geographicinformation space data.This paper used different flying height images for study and analyzed the theoreticalknowledges of making DLG and DOM based on UAV low-altitude photogrammetrytechnology around the characteristics of UAV low-altitude photogrammetry technology, filedcontrol surveying method of photogrammetry, the key technology of indoor processing UAVimages and so on. Then, taking three test areas as example，the paper empirical studied andanalyzed the precision of DLG and DOM which layed the foundation for the theory andpractice for practical applications. Mainly includes:(1) The paper introduced the process and key technology of producing digital productswith UAV images which mainly includes image distortion correction, extracting image featurepoints, image matching, aero-triangulation and producing digital products, etc.(2) The paper empirical studied the schemes of laying picture control points and factorsof influencing the mapping precision based on UAV low-altitude photogrammetry using threesurvey areas: China University of Mining&Technology, Qian Ying coalmine and Qi Dongcoalmine and analyzed the precision of DLG and DOM.(3) In order to improve the elevation precision of survey area, the paper used themathematical model to simulate the elevation correction value and established the quadraticpolynomial fitting model of elevation points of topographic map map,which applied in thesurvey areas and compared the topographic map elevation precision before and after elevationfitted.