Design, Performance and In-Orbit Evaluation Results of Tiangong-2 Wide-Band Imaging Spectrometer

Abstract

The system design, performance and in-orbit evaluations of a push-broom wide-band imaging spectrometer (WIS) on Tiangong-2 space laboratory is introduced. The WIS has 100 m spatial resolution in ocean color bands (FOV is around 42°), which is the highest compared to other in-orbit ocean color sensors (GOCI, MODIS, VIIRS, and OLCI). Besides, WIS includes visible and near infrared (VNIR), shortwave infrared (SWIR) and thermal infrared (TIR) channels and has excellent performance in ocean color monitoring, and SNR in 0.4–0.8 μm is more than 400 at typical oceanic radiance. Average SNR at SWIR is more than 550 at typical atmosphere radiance. Moreover, the instrument’s average NE⊿T at TIR is lower than 20 mK, which is one of the best. The in-orbit tests reveal that the ocean color components retrieved by WIS are highly consistent with the results from the typical ocean color satellite sensors (MODIS, VIIRS and GOCI), but have finer structures due to higher spatial resolution.