INSAT-3DS Imager

INSAT-3DS Imager is the mission's six-channel geostationary meteorological imager, distinct from the INSAT-3DS Sounder ^[1][2]. It covers visible, shortwave-infrared, mid-wave infrared, water-vapour, and split-window thermal-infrared bands for full-disc imaging, cloud motion winds, outgoing longwave radiation, snow and cloud discrimination, and sea-surface-temperature retrieval over the Indian region ^[1]. The band set follows the INSAT imager class: VIS 0.52-0.72 um, SWIR 1.55-1.70 um, MWIR 3.80-4.00 um, water vapour 6.50-7.00 um, TIR-1 10.2-11.2 um, and TIR-2 11.5-12.5 um ^[1][3]. Ground sampling is 1 km for VIS/SWIR, 4 km for MWIR and thermal-window bands, and 8 km for the water-vapour band, with 10-bit imaging ^[1]. The 3DS meteorological payload session on 2024-03-07 returned nominal payload parameters, and the 3DS generation adds updates in radiometric accuracy, black-body calibration, thermal management, and imaging throughput while retaining the six-channel imager role ^[2][1].