Research On GPS/IMU Supported Aerial Triangulation Method With Exposure Delay

GPS/IMU integrated navigation system for aerial surveycan directly obtain the position and attitude information of the captured image in the exposure time and can significantly reduce the number of ground control points,which makes the system important in UAV aerial photogrammetry and changes the working mode of the traditional aerial survey.With the continuousdevelopment of GPS/IMU Technology,the accuracy of data acquisition is getting higher and higher,and the technology has become an indispensable equipment in aerial photogrammetry.However,due to the general light small unmanned aerial vehicle small volume and light weight,only equipped with navigation GPS/IMU combination system,the lack of exposure synchronization device limits the application of unmanned aerial photogrammetry in the field of high precision measurement.In this paper,through the analysis on principle of GPS/IMU integrated system,summed up the research methods of Aerial triangulation with GPS/IMU and principle are deduced in detail.The exterior orientation elements GPS/IMU combination system(position and attitude parameters)to coordinate the actual conversion application in photogrammetry system,and based on the analysis of problems the existing three GPS/IMU auxiliary empty technology,so as to establish a GPS/IMU method for camera exposure auxiliary aerial triangulation.The feasibility of the proposed method is demonstrated by selecting the data from two experimental areas.The experimental results show that the GPS/IMU aerial triangulation,which takes into account the camera exposure delay,effective and feasible.The main contents of this paper are as follows:(1)This paper illustrates the important role of GPS/IMU system in aerial photogrammetry,which based on the method,principle and technology ofAerial triangulation with GPS/IMU integrated system.(2)This paper analyzes the transformation relation of the coordinate elements obtained from the external orientation elements obtained by the GPS/IMU system and the application of photogrammetry.The meaning of eccentric angle and eccentric component are discussed.According to the requirements of the relevant regulations,on the design of the ground base station and control field and the corresponding solutions in the aerial flight.(3)Aiming at the existing problems in the UAV aerial triangulation GPS/IMU auxiliary technology,analysis of the UAV aerial drones,GPS/IMU auxiliary aerialtriangulation,established to take into account the camera exposure GPS/IMU auxiliary aerial triangulation system error model.(4)By selecting two sets of data obtained from UAV equipped with GPS/IMU system,with conventional aerial triangulation and GPS/IMU direct orientation method,GPS/IMU aerial triangulation method and adjustment of the GPS/IMU auxiliary aerial triangulation method for camera exposure delay.Experimental results show: GPS/IMU auxiliary aerial triangulation can greatly reduce the number of image control point layout,and the number of control points are required only 50% of the conventional aerial triangulation,but it can achieve the same accuracy;by comparing the results of the GPS/IMU assisted aerial triangulation with the existing GPS/IMU aided aerial triangulation adjustment,the GPS/IMU aided aerial triangulation adjustment method which takes into account the camera exposure delay can reduce the number of control points on the basis of the original accuracy by about 1/3.