Geostationary Ocean Colour Imager (GOCI) is the first Ocean Colour Imager to operate from a Geostationary Orbit. It was developed by Astrium SAS under KARI contract in about 3 years between mid 2005 and October 2008 and integrated on-board COMS satellite end 2008 aside the COMS Meteo Imager (MI). COMS satellite was launched in June 2010 and the in-orbit commissioning tests were completed in beginning of 2011.
The mission is designed to significantly improve ocean observation in complement with low orbit service by providing high frequency coverage. The GOCI is designed to provide multi-spectral data to detect, monitor, quantify, and predict short-term changes of coastal ocean environment for marine science research and application purpose. Target area for the GOCI observation in the COMS satellite covers a large 2500 x 2500 km2 sea area around the Korean Peninsula, with an average Ground sampling distance (GSD) of 500m, corresponding to a NADIR GSD of 360m.
The presentation will shortly recall the mission objectives and major instrument requirements, and then present the results of inorbit testing and validations. All functions and in particular the CMOS detector matrix operate nominally. Performances evaluated in orbit (SNR, MTF, etc.) show results above the requirements. Finally, in-orbit calibrations using the sun diffuser provide very satisfactory consistency with the ground characterisation. GOCI is now delivering operational products and proving the interest of Geo observation in the Ocean Colour applications
The Geostationary Ocean Color Imager II (GOCI-II) is the next generation of GOCI, which is one of the main payloads of the Korean COMS satellite. GOCI was the first ocean color sensor in the world operating on the geostationary orbit.
Geostationary Ocean Color Imager (GOCI) is under development to provide a monitoring of ocean-color around the Korean Peninsula from geostationary platforms. It is planned to be loaded on Communication, Ocean, and Meteorological Satellite (COMS) of Korea. In this paper main mission of GOCI and corresponding major technical requirements are introduced. Also characteristic of the GOCI radiometric model for calibration is introduced. The GOCI is modeled as a nonlinear system in order to reflect a nonlinear characteristic of detector. Radiometric calibration concept is explained through radiometric parameter estimation method and offset correction method. For the GOCI, the offset signal depends on each spectral channel because dark current offset signal is a function of integration time which is different from channel to channel. The offset parameter estimation method using offset signal measurements for two integration time setting is described. Also error propagation for radiance estimation is examined in this paper. The error propagation for nonlinear GOCI instrument will be slightly larger than a linear instrument. The increase of error propagation induced by the nonlinear parameter depends on the integration time and the input radiance.