Optical Multi-Satellite data Calibration for Image Integration and Harmonization

Radiometric calibration of satellite imaging is important for image accuracy in environmental monitoring and applications. In this study, we performed vicarious radiometric calibrations relying on in situ data using Spectroradiometer for absolute surface reflectance and Sun photometer for atmospheric information at the satellite observation day. The field measurements have been used as input to MODTRAN6 for TOA radiance estimation and further conversion to TOA reflectance. Images from constellation satellites of GRUS (GRUS-1A) and PlanetScope (PS2 and PSB.SD instruments) captured on 5 August 2021 were used in the study. The TOA reflectance estimated by MODTRAN6 and acquired by satellite instruments has been correlated to derive an equation for satellite data calibration. The calibration results have shown an improvement in harmonization of the different sensors data for multi-temporal application.