Study On The Precision Of Large Scale Topographic Map Of Unmanned Aerial Vehicle

With the continuous updating of terrain data,the accuracy of large scale topographic maps in different terrain is also increasing.Although the traditional aerial survey has many advantages,it is influenced by the factors such as different terrain,high angle of image,different air height,and the distribution of control point,so that the key technologies of aerial triangulation,image preprocessing,image matching and beam method adjustment can not play a full role in aerial survey.The accuracy of the shape diagram,especially the elevation precision.With the continuous development of photogrammetry technology,the low altitude photogrammetry of UAV has more advantages than the previous aerial photogrammetry,and plays a more and more important role in the land aerial survey.With the development of UAV and POS(Position and Orientation System)technology,even adding a small number of control points can meet the precision requirements of 1:500,but the improvement of precision is not obvious.In special terrain,it is difficult to satisfy the large scale accuracy by using the aerial triangulation method and the special layout method.In large water areas,the baseline method can not satisfy its accuracy.This paper,based on the project of the confirmation of the right of contracted management of rural land in Mengaiti County,Kashi,Xinjiang,deals with the data obtained by the unmanned aerial vehicle(UAV)image,and studies the large scale mapping of 1:500 in the water area and the layout of other special terrain 1:1000 large scale mapping to improve the large proportion of 1:500 and so on.The elevation accuracy of the ruler topographic map.The main research work has three aspects as follows:(1)Taking the UAV system as the research object,the key technologies such as control point layout,control point measurement,lens distortion correction,difference GPS and image matching are discussed on the basis of analyzing the classification of UAV,the composition and characteristics of UAV system,the acquisition of image and the requirements of aerial photography accuracy.It is a study of large scale such as 1:500.The accuracy of topographic map provides guidance.(2)Taking the engineering practice as an example,four kinds of test schemes are designed according to the difference of the baseline number,and the best scheme is obtained by analyzing the middle error of each index of the control point,and the best scheme is compared with the scheme designed in the vertical construction route method in this paper.It is found that the vertical configuration route method not only sets less control points,but also improves the elevation precision of 0.030513 m,and is more advantageous to the large scale topographic map of 1:500 in water area.(3)The work of Surveying and mapping in the aerial triangulation is carried out.Through the special distribution of the different terrain in the measured area,the influence of the special cloth point method on the elevation accuracy is obtained,thus the amplitude of the precision is determined,the elevation accuracy obtained by this special distribution method and the Gao Chengjing obtained by the two polynomial fitting method of this article are obtained.Compared with the results,the results show that the two order polynomial fitting method is higher than this special distribution method,and the amplitude is higher,which provides a reference for the study of the accuracy of the 1:1000 large scale topographic map.