Development and testing of a generic sensor model for pushbroom satellite imagery

A new generic pushbroom sensor model for high-resolution satellite images in which the orbit and attitudes are modelled by splines is presented. Direct observations for the satellite orbits and attitudes provided in imagery metadata files are used to determine the parameters of these splines. As such observations are contaminated by systematic errors, the new sensor model also incorporates error correction for the orbit and attitude angles. Camera model parameter definitions and file formats generally differ between satellite pushbroom scanners, and the system image- to object-space transformation models are not always compatible with a sensor model based on the familiar perspective model applied in photogrammetry. In order to make the new sensor model applicable to a large number of satellite imaging systems, these vendor-specific definitions are first mapped to the definitions of the new sensor model during data import. This is illustrated for QuickBird, SPOT 5 and ALOS PRISM imagery. The model has been extensively tested using imagery from these same three satellites, over test sites in Melbourne and Bhutan. The tests have shown that the new sensor model can produce georeferencing accuracy of 1 pixel and better when biases in orbit and attitude data are compensated.