천리안 해양관측위성의 궤도성 복사보정 운영 상황

Abstract

After the successful launch and in-orbit test of GOCI(Geostationary Ocean Color Imager), one of main payloads of COMS(Communication, Ocean and Meteorological Satellite), the new era of ocean color remote sensing has begun with the worlds first ocean color observation sensor in geostationary orbit, GOCI .In order to retrieve the radiance from the GOCI RAW data, in-orbit radiometric calibration with reference light source is required. In case of GOCI, Sun is the reference light source for the in-orbit radiometric calibration. Solar Diffuser(SD) and Diffuser Aging Monitoring Device(DAMD) as a second solar diffuser are implemented on GOCI for in-orbit solar calibration. SD and DAMD of GOCI are QVD(Quasi-Volumic Diffuser) type solar diffusers made of fused silica which are very well-known for the low solar UV sensitivity. Diffusers of GOCI are made of same material in the same fabrication conditions.Linear gain(G) and 3rd order non-linear gain(b), coefficients of GOCI radiometric model to calculate the radiance from DN, can be acquired from the calibration images observed with diffusers at local night time. The GOCI linear gain value is about 0.49 for Band 1(412nm) and non-linear gain value is about -1.38E-9 for Band 1(412nm) from the pre-launch GOCI ground test results, and there is no significant variation between the results of ground test and on-orbit nominal operation. We prelds first ocean color observation sensor in geostationary orbit, GOCI .In order to retrieve the radiance from the GOCI RAW data, in-orbit radiometric calibration with reference light source is required. In case of GOCI, Sun is the reference light source for the in-orbit radiometric calibration. Solar Diffuser(SD) and Diffuser Aging Monitoring Device(DAMD) as a second solar diffuser are implemented on GOCI for in-orbit solar calibration. SD and DAMD of GOCI are QVD(Quasi-Volumic Diffuser) type solar diffusers made of fused silica which are ve