A test result on positional accuracy of KOMPSAT-2 pan imagery

KOMPSAT-2 (KOrea Multi-Purpose SATellite-2) was launched in July 28 2006 with specification of one-meter resolution panchromatic and four-meters resolution multi spectral sensors in 15km swath width. To help understand KOMPSAT-2 positional accuracy, this paper reports a test result on accuracy of three KOMPSAT-2 images covering the same area. For the purpose, a number of ground points were acquired from the bundle adjusted stereo aerial images over the entire target area. First, accuracy of the provided RPC and ephemeris data was tested and analyzed. Second, indirect georegistration was attempted to improve the accuracy by modeling geometric errors based on RPC correction and physical sensor modeling. For RPC correction, shift-only, affine, and second order polynomial models were tested. The physical sensor modeling was carried out by estimating constant bias or linear drift in the attitude angles. In the last, ground restitution accuracy was analyzed even though the across track image pairs do not have optimal convergence angle for restitution.