ANALYSIS OF GEOMETRIC AND ORTHOGONAL CORRECTION ACCURACY FOR CAS-500 SATELLITE IMAGES

Abstract. This paper reports on geolocation accuracy of image products generated from Precision Image Processing (PIP) system developed for CAS-500 Satellite images. CAS-500, launched on 22 March, 2021, will be used mainly for land monitoring and 1:5000 scale mapping over the Korean Peninsula. For this purpose, ground control points (GCPs) and a Digital Terrain Model (DTM) have been collected over the Peninsula and integrated into the PIP for the generation of precision image product in an automated manner. The goal of this paper is to analyze the geolocation accuracy of image products generated from the PIP. Target geolocation accuracy of the PIP was set as 2 pixel RMSE using the internal GCP DB and DTM. Since CAS-500 images were not distributed yet, the analysis was performed using 13 KOMPSAT-3A satellite images, having similar specifications to CAS-500. The result showed that the accuracy of precise sensor models were about 1.797 pixels in South Korea and 1.907 pixels in North Korea. The accuracy of orthoimages were about 1.24 meters in South Korea and 1.59 meters in North Korea. Overall, the geolocation over North Korea was not as good as that over South Korea. It was judged that the quality of GCPs and DTM over North Korea affected the geolocation accuracy and, however, the accuracy gap was not too severe. The PIP system should produce image products within the targeted geolocation accuracy when CAS-500 delivers high resolution images over the Korean Peninsula.