This article presents a method to generate ortho-images with digital elevation model and a few ground control points. The method has been integrated to take into account the geometric distortions of the full geometry of viewing (sensor-platform-Earth), and unified to process images from different sensors (VIR and SAR) on various platforms (airborne and spaceborne). Results from eight types of images show an absolute accuracy of 1/3 of a pixel for VIR satellite images and one to two pixels for the other images (SAR and airborne), and a relative accuracy of one pixel between the image. Mosaicing of these ortho-images with the road network overlaid confirms the relative and absolute accuracies.
"Rigorous geometric processing of airborne and spaceborne data", Proc. SPIE 2315, Image and Signal Processing for Remote Sensing, (30 December 1994); doi: 10.1117/12.196780; https://doi.org/10.1117/12.196780