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• At present the geometric correction prototype has been developed to a working state. It has been tested on the Barrax test site, with Mode 1 images. But further development still is required; especially the use of a DEM for line of sight interception, which has been left for the final implementation stage in order to simplify the model while being developed. Also, a refined GCP input system needs to be included. It needs extensive testing on other sites apart of Barrax, but the corresponding telemetry needs to be provided by ESA as such data is not publicly available yet. It is also necessary to test other operation modes apart of Mode 1, especially the peculiar Mode 5.

• The inputs needed by the algorithm are: telemetry with the satellite position, velocity and image timing, target centre coordinate, local DEM (in the final version). The outputs of this algorithm consist on the coordinates map in IGM files, or the rectified images if the desired output is the rectified images, then they should be also provided. As side product, observation angles maps can be produced for each of the images.

• It must be noted that this method requires ESA to provide the corresponding telemetry for each acquisition. It is possible to use orbit propagation models in order to substitute the telemetry in case it is missing, but it has not been implemented yet.

The use of IGMs might be advantageous for reducing storage space as well as for those processing algorithms that might be computationally intensive but do not required rectified images, as the number of pixels to be processed is greatly reduced. They provide geographic location of each pixel; therefore algorithms based on coordinates can still be applied (if they accept the geographical information in this form).
Spatial correlation is a possible approach to automatically set GCPs to reduce the burden on the user but it still needs supervision on each of the points detected as it is typical to get false matches.

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