In-orbit Stray light Performance Simulation for Geostationary Ocean Color Imagers

We report stray light modeling and analysis results for the current and proposed next generation ocean color imagers with Sun and the target area around Korean penninsular as viewed from geostationary orbit. The imagers used in this study are GOCI of 140mm in diameter and a proposed next generation GOCI (GOCI-II) of about 300mm in diameter. First, we built complete GOCI and GOCI-II 3D optical system models with the realistic surface characteristics. These optical models were incorporated into the in-house built Intergrated Ray Tracing (IRT) algorithm, connecting the Sun, the measurement target area and the instruments via single ray tracing computation for radiative transfer and scattering. The stray light level was then estimated for possible orbital configurations for science measurement and in-orbit calibration operation. The simulation details, results and their implications are presented.