Orthorectification Using Rational Polynomials
You can orthorectify certain types of satellite images that are supplied with a mathematical model of the image geometry in the form of a set of rational polynomial coefficients. This procedure also requires a digital elevation model. You can often improve the fit of the rational polynomial model to a particular image by regeoreferencing the image using accurate 3 D ground control points.
About Rational Polynomial Models
Acquiring a DEM
Elevation Units and Reference Surfaces
Obtaining the Geoid Height
Regeoreferencing the Image
Georeference with RPC Model
Control Points from GPS Survey
Evaluating Control Points