THREE-DIMENSIONAL EARTH MODELLING PERFORMANCE ANALYSIS OF GÖKTÜRK-2 SATELLITE

Following RASAT, Gokturk-2, placed into its orbit as Turkey’s second domestic production of earth observation, has three times higher spatial resolution (2.5 m) than RASAT and has much more advanced stereo vision capability. However, like all-optical imaging satellites, Gokturk-2 has problems in data quality due to reasons such as sensor geometry, contrast, dense forest cover in the field of view and topographic slope. In this study, it is aimed to evaluate the horizontal and vertical geolocation accuracy performance of three-dimensional Digital Surface Models (DSM) derived from Gokturk-2 stereo images in comparison with a reference DSM obtained by traditional photogrammetry method in Derik district of Mardin province with high slope and variable topographic conditions. The results demonstrated that the three dimensional topographic representation capability of Gokturk-2 is quite successful despite offering a medium spatial  resolution. The Gokturk-2 DSM has an absolute horizontal geolocation accuracy of ≤0.1 pixels (25 cm) both for X and Y directions. On the height, it provides accuracy as standard deviation of 7.3 m and normalized median absolute deviation of about 5.7 m.