Radiometric calibration and total uncertainty budget determination of Göktürk-2 satellite

Monitoring radiometric calibration parameters of optical remote sensing data is a necessary requirement that provides a further quantitative examination of the data, continuity and reliability. Organizations producing satellite data should provide the end-user with the calibration coefficient of each sensor band along with the measurement uncertainty percentage. In radiometric calibration studies, test sites with high spatial homogeneity and stable atmospheric conditions are needed. Salt Lake, the second largest lake in Turkey, is one of the eight calibration fields in the world for calibration studies. However, to complete the site studies in Salt Lake, which is a 1st Degree Natural Protected Area, in the shortest time and with optimum resource use, measurements should be carried out with an appropriate methodology. In this study, considering the constraints mentioned above, radiometric calibration and uncertainty analysis of Turkey's first high-resolution satellite Göktürk-2 was carried out using terrestrial and atmospheric data collected from Salt Lake in 2017 and 2018. Calibration coefficients of each band were calculated and uncertainty analysis was performed for each band by determining the parameters that cause uncertainty in estimating of the calibration coefficient. Both for absolute and cross-radiometric calibration methods, the effects of uncertainty sources on the total uncertainty budget are discussed. As a result of the studies, the calibration coefficients' measurement uncertainty calculated with the absolute radiometric calibration method is below 4%. The measurement uncertainty in obtaining the calibration coefficients with cross-radiometric calibration method is around 2%. In this study, for the first time, the measurement uncertainty in estimating the calibration coefficients of Göktürk-2 was calculated.