In May 2002, SPOT-5 was set to join its three sister satellites SPOT-1, SPOT-2 and SPOT-4, all operating on the same orbit. This new satellite is designed to ensure SPOT-5 data users continuity of service, enhanced image quality and improved services. Moreover, it offers significantly improved resolution (2.5 meters in black and white and 10 meters in color) and operational capabilities, chiefly through a new High-Resolution Stereoscopic instrument (HRS).
This research points toward investigating the possible positioning accuracy of single high-resolution SPOT imagery. The test image, which is a panchromatic SPOT-5 image with a 2.5 m resolution, covers an urban area in the region of Kofra, Libya . A set of eighteen points, representing well–identified natural features is selected on the image. Their coordinates in a 3-D object coordinate system are obtained by using precise terrestrial surveying methods. A 2-D transformation has been carried out from the image coordinate system to the object coordinate system utilizing well-distributed sets of the selected points. Similarity, affine and projective transformation models are applied in the transformation process and their results are compared through a check-point analysis. According to the achieve results using different configuration of transformation points, the planimetric positioning accuracy figures resulted from the three models are almost similar and reach the image ground sample distance of the image.
|
