On-orbit Spectral Calibration Method For Imaging Spectrometer Using Atmospheric O_2 Absorption Peak and Pr-Nd Glass Characteristic Spectra

摘要

Space-borne imaging spectrometer can be used for ocean color remote sensing and coastal zones monitoring. To meet the demand of quantitative remote sensing inversion, the imaging spectrometer needs precisely spectral calibrated before launching. However, due to the changes of space environment and degradation of the instrument performance, maybe the central wavelength or spectral width of each channel in the spectrometer varies after launching. Thus, on-orbit spectral characteristics check even recalibration for the instrument is necessary. The imaging spectrometer is capable of channel programmable and the spectral width of every pixel line of the array CCD is 2.5nm. In the field imaging experiments, the instrument showed an atmospheric O_2 absorption peak near 765 nm. This characteristic peak coordinating with Pr-Nd glass, which belongs to the on-board calibration mechanism, can be used for on-orbit spectral calibration. Also, it can be used independently to calibrate the central wavelength of each channel during the earth observation. Empirical research shows that this method is not only simple and applicable but also can achieve precision of 1.25 nm and meet the practical requirements.