In the time series frequency analysis, LANDSAT showed a sharp decline during periods 3-4, and KOMPSAT, MODIS, and GEOKOMPSAT showed a sustained increase over periods 1-4 (Figure 8(b)).
 EESA Earth Online (KOMPSAT), https://earth.esa.int/web/ guest/missions/3rd-party-missions/current-missions/kompsat-2.
The mission objectives of KOMPSAT-3 are to provide continuous earth observation after KOMPSAT 2 and to meet the nation's need for high resolution optical images required for the Geographic Information System (GIS) and other land, environmental, agricultural, and oceanographic monitoring applications.
Here we analyzed the orthoimage accuracy of the KOMPSAT optical images.
A variety of data was used to perform the KOMPSAT image correction experiments for a wide range of study areas.
The GCPs for orthorectification of the KOMPSAT images were extracted and used from aerial orthophotos that had a spatial resolution of 0.25 m and a horizontal accuracy of less than 1m (RMSE).
For this study, orthorectification of KOMPSAT optical images was performed through the process shown in Figure 4.
The second experiment used various control point sources, and DEM was performed to investigate the effect of ground reference data for orthorectifying submeter high resolution KOMPSAT images.
In the case of KOMPSAT, many studies have been carried out to improve the position accuracy using the bias-compensation method [11,19, 20].
Image fusion based on the High-Pass Filter Additive (HPFA) technique was applied in order to generate high resolution multispectral KOMPSAT images.