A robust method to calculate exterior orientation elements of image

How to acquire elements of exterior orientation has been the problem to be solved in photogrammetry.Spatial resection used GCPs(Ground Control Points) to calculate the parameters of exterior orientation,but in many cases the data for calculation contains outliers.Outliers may account for 1% ~ 10% in all.A robust method of detecting the outliers and calculating the image parameters were presented in this paper.It treats the GCPs as the unknown parameters and linearizes the equation,achieves good results and deletes the outliers finally.This method improves the reliability of calculation and can get the precision of GCPs and pixel points coordinates.