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Toshiaki Hashimoto 
  
GEOMETRIC CORRECTION OF ADEOS-II/GLI 
Toshiaki HASHIMOTO 
Center for Environmental Remote Sensing (CEReS), Chiba University, Japan 
hashi @ceres.cr.chiba-u.ac.jp 
Working Group 1/5 
KEY WORDS: Algorithms, Mapping, Sensors, Orientation 
ABSTRACT 
The GLI (Global Imager) on board the ADEOS-II is an optical mechanical scanner with 36 channels and the spatial 
resolution of 1 km and 250m at nadir. It is the successor of the ADEOS/OCTS (Ocean Color and Temperature 
Scanner) and observed the Earth surface only in daytime. The author is one of the Pls (principal investigators) and in 
the charge of precise geometric correction of the GLI. This paper describes the main characteristics of the GLI, the 
methodology of geometric correction and some products. 
1 INTRODUCTION 
The ADEOS-II (Advanced Earth Observing Satellite-IT) has being developed and will be launched in 2001 by National 
Space Development Agency of Japan (NASDA). The main mission of ADEOS-II is summarized in three points: to 
monitor regularly the water and energy cycle in the global climate system, to estimate quantitatively the biomass and 
fundamental productivity in the carbon cycle, to detect the signal of long term climate changes. To realize the mission 
objective, it is equipped with five sensors: the Global Imager (GLI), the Advanced Microwave Scanning Radiometer 
(AMSR), the Improved Limb Atmospheric Sounder-II (ILAS-II), the SeaWinds and the Polarization and Directionality 
of the Earth’s Reflectance (POLDER). 
The GLI is an optical mechanical scanner with 36 channels. It is the successor of the OCTS on board the ADEDOS and 
very similar to EOS-Terra/MODIS. It is designed for four kinds of application fields like atmosphere, ocean, land and 
cryosphere. In the field of land application, the geometric accuracy is very important because of multi-temporal 
analysis, image composite. 
The initial checks of ADEOS data indicated that the geometric accuracy of the OCTS imagery was about 10 pixels. 
NASDA and some organization examined the factors for such terrible errors and found out three factors; 1) the bug of 
the software for determining satellite position, 2) the insufficiency of the algorithm for getting satellite attitude, 3) the 
miss-alignments of the sensors. Among them, the first factor was easy to fix. With respect to the second one, a new 
algorithm adopted to the ADEOS-II satellite has been examined. The third one was corrected using a number of ground 
control points (GCP) from many OCTS images. The modification of processing system at the ground station lead to the 
geometric accuracy of the OCTS imagery within a few pixels. 
Some factors of the ADEOS-II concerning geometric accuracy will be improved rather than those of the ADEOS. For 
example, a differential GPS system and a star sensor will be equipped in order to achieve accurate satellite position, to 
monitor satellite attitude, respectively. It will be probable that the geometric accuracy of the GLI will be not sufficient 
in spite of such improvements. 
If the satellite position and attitude are sufficiently accurate and the sensor alignments do not change after the launch, 
Systematic geometric correction would achieve the sufficient accuracy. However, the experiences of the 
ADEOS/OCTS will indicate that the satellite attitude will not be so precise and the sensor alignments may change after 
the launch. NASDA is preparing the precise geometric correction system utilizing GCPs in case of insufficient 
geometric accuracy. In the system, such uncertain parameters as the satellite attitude and the miss sensor alignment are 
corrected on the basis of collinearly condition of photogrammetry. 
The sensor alignments will be corrected during initial check out period. The geometric correction system in the normal 
Operation is as follows. The GCPs are extracted automatically by image matching of coastal lines. The precise satellite 
position and attitude are determined using the GCPs. A rectified image is generated using the newly determined 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part Bl. Amsterdam 2000. 141