Investigations on the radiometric and geometric quality of rasat pan imagery

Abstract

RASAT is the second Turkish Earth Observation satellite which was launched in 2011. It operates with pushbroom principle and acquires panchromatic and MS images with 7.5 m and 15 m ground resolutions, respectively. The swath width of the sensor is 30 km. Within this study, radiometric and geometric qualities of RASAT panchromatic channel images and its products are analyzed. RASAT stereo pair acquired over Kesan city in Edirne province of Turkey has been used for the investigations. The raw RASAT data (L0) are processed by the Turkish Space Agency (TUBITAK-UZAY) to produce higher level image products. The image products include radiometrically processed (L1), georeferenced (L2) and orthorectified (L3) data, as well as pansharpened images. The image quality assessments include visual inspections, noise, MTF and histogram analyzes of L1 images. The geometric accuracy assessments include exterior orientation modeling using polynomial functions with L1 stereo images and dense point matching with L2 orthorectified images. In this paper, the georeferencing accuracy results of the latter approach are presented together with the radiometric accuracy investigation results.