sensor model and the data pre-processing procedure of the ADS40 three-line sensor are briefly addressed firstly.Then a comprehensive study is concentrated on the mathematic sensor model of the ADS40 images
in which an efficient iterative searching algorithm was developed to determinate the corresponding scan line given an object point.After that the paper describes an efficient ortho images generation procedure that can be applied directly to the ADS40 Level 0 products.Test results show that the proposed ortho-rectification procedure works well and effectively and also
the accuracy fulfills the requirements of the ortho image generation with corresponding map scale.