Publications

Takaku, J; Murakami, H (2024). GCOM-C/SGLI In-Orbit Geometric Analysis and Calibration. IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, 62, 5409114.

Abstract
The second-generation global imager (SGLI) was launched in December 2017 onboard the global change observation mission-climate (GCOM-C) and has been observing daily global data in 23 different channels using three sensor units: the visible and near-infrared radiometer with nonpolarization (VNR-NP), one with polarization (VNR-PL), and the infrared scanning radiometer (IRS). The VNR-NP uses a push-broom scanner to observe 11 spectral bands with 250-m and 1-km spatial resolutions. The VNR-PL collects the polarization data for three angles in two spectral bands with a spatial resolution of 1 km by a push-broom scanner. The IRS observes six spectral bands with spatial resolutions of 250 m, 500 m, and 1 km by a whiskbroom scanner. Their geometric processing was one of the technical challenges, where the 23-channel data acquired by the three independent sensors have different geometric characteristics. For their calibration, the imageries of the Advanced Visible and Near-Infrared Radiometer Type-2 (AVNIR-2) were used as the ground control points (GCPs). Their finer resolution, geolocation accuracies, and global distribution made the calibration more detailed. A systematic strategy was conducted in the calibration, which combines the absolute errors from GCPs and the relative errors among different channels. The errors were measured by the image-matching technique between different spectral bands based on their image correlations. As a result, the geolocation accuracies have satisfied the specification of 0.5 pixels (rms) for over six years since launch. This article describes the geolocation approach and the geometric calibration of the SGLI.

DOI:
10.1109/TGRS.2024.3472078

ISSN:
0196-2892