Research on method for sub-pixel location of star image

The common methods for sub-pixel location is introduced,i.e.centroid algorithm,Gaussian fitness algorithm,paraboloid fitness algorithm.The Gaussian fitness algorithm has the highest precision in theory,however when experiment is undertaken on real star image shot in our project the result is far from ideal and the error goes beyond the permitted range.Thus centroid algorithm is taken to calculate the coordinates of stars in the image.This time experiment proved that the method's precision completely meet the need of sub-pixel level and the application for later moment.