Research On Key Technology Of Airborne Li Dar Accuracy Evaluation Based On RANSAC-TLKS

In recent years,the airborne Li DAR measurement technology in urban modeling,transportation planning,forestry monitoring has been widely used,its data acquisition precision can meet the application requirements is the focus problem,so to establish a reliable assessment model precision,optimization precision evaluation method,to improve the accuracy of airborne Li DAR evaluation is necessary.In this regard,many scholars have proposed various non-control and non-inspection field methods to assess the accuracy of airborne radar.However,most of these methods remain in the theoretical stage and require a lot of post-processing work,which is difficult to achieve.In actual production application,by setting the control target calibration flight evaluation is still the most direct way,because the lidar point cloud has irregular discrete,when using standard target cloud to assess so will still be affected by the discrete coarse almost,thus unable to target point cloud through accurate fitting of the target coordinates.Based on this,this paper adopts a variety of optimization algorithms to optimize the calculation process of accuracy evaluation on the basis of the field control target.The main research contents of this paper are as follows:1?first of all,the study of airborne Li DAR precision evaluation present situation has carried on the induction and summary,analyzes its deficiencies,and presents in this paper,the optimization of airborne Li DAR precision evaluation method and technical route,respectively on the basis of the airborne Li DAR ground positioning principle and error sources of a system,to provide the precision of the follow-up evaluation research foundation.Then,the influence of each error source is analyzed through the simulation experiment parameter data.On this basis,the simulation precision is calculated according to the error parameters of the airborne Li DAR system.2?RANSAC(Random Sampling consistency)algorithm combined with TLS(Total least squares)fitting method was proposed to fit the target cloud plane.Through setting threshold RANSAC algorithm for iterative calculation,excluding outside points of small fit(outliers)to reduce the effects of coarse almost,considering the TLS algorithm combining with laser foot point X,Y,Z three directions the influence of the error,to meet the requirements of the accuracy of the station point to simulate plane(inliers),then using the graphic information obtained from the fitting of minimum edge point circle fitting method is applied to the fitting for the target center point coordinate is calculated,so as to realize the optimization of accuracy evaluation process,to achieve the purpose of improve the evaluation precision accuracy.3?Field inspection and calibration flight experiment was designed and carried out.By selecting 4 target cloud data within the calibration field for fitting calculation,three algorithms of RANSAC,TLS and minimum edge point circle fitting were successively adopted to optimize the accuracy evaluation process,and the accuracy evaluation of domestic airborne Li DAR system was realized.The evaluation results show that the error between the evaluation results and the simulation accuracy and the calibration design accuracy is in centimeters,and the evaluation method in this paper is simple and feasible.