Modeling Pushbroom Scanning Systems

The present study aims at modeling push broom imaging systems on board a spacecraft with a full force rigorous orbital photogrammetric mode as a digital solution. During the modeling stage, we adopt a hybrid time domain model wherein keplerian orbital parameters are modeled in continuous time domain, while attitude parameters are, modeled as polynomials in discreet time domain. The output of the model is subsequently used to realize an ortho-rectified image by single stage resampling. The image rectification procedure adopted is based on back projection by indirect method but is redesigned to eliminate several unnecessary computations that are made on a pixel by pixel basis and is illustrated with a Spot data set. The study illustrates the excellent and very promising potential of adopting Singular Value Decomposition SVD in the bundled adjustment process. The study brings out that this two stage approach results in a significant reduction in computational time while retaining the product location accuracy. Geometric rectification is made by a single stage resampling, which significantly enhances the radiometric fidelity of the processed data when compared with conventional techniques used in operational environments.